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Sample records for barn reactor

  1. Mor-barn samspillet

    DEFF Research Database (Denmark)

    Røhder, Katrine; Davidsen, Kirstine Agnete; Trier, Christopher Høier;

    2015-01-01

    Denne artikel beskæftiger sig med, hvordan risiko og modstandsdygtighed overføres fra forældre til barn, når mor lider af en alvorlig psykisk lidelse. Vi vil argumentere for, at det er helt centralt at undersøge forældre-barn relationen og det tidlige samspil, hvis man vil forstå spædbarnets...

  2. Klar til barn : Kundskabsoversigt

    DEFF Research Database (Denmark)

    Ertmann, Bo; Guldager, Else; Nørgaard-Nielsen, Sofie

    forældrene er i fare for at reagere voldeligt over for deres børn. Et af de aspekter, der adskiller Klar til barn fra andre lignende projekter i Danmark, er, at forældrekursernes udformning og indhold er baseret på en grundig research af internationale erfaringer med forældreuddannelsestilbud. Konceptet blev...

  3. Det postmoderne barn

    DEFF Research Database (Denmark)

    Hansen, Ole Henrik

    2010-01-01

    Den nye psykologi fokuserer på dynamik og intersubjektivitet, mens den gamle var optaget af faser og udviklingstrin. Den postmoderne forståelse af det lille barn opfatter ikke faserne som aflåste, historiske sandheder, men som levende narrativer. Og så får det nye børnesyn indflydelse på Frode og...

  4. Barn med Asperger syndrom

    OpenAIRE

    Ahlström, Hanna

    2003-01-01

    Det här examensarbetet handlar om barn med Asperger syndrom. Syftet med arbetet var att ta reda på vad Asperger syndrom är och hur man som lärare kan hjälpa dessa elever på bästa sätt. Jag är intresserad av elever som har det svårt och antar att jag någon gång under min tid som lärare kommer att stöta på dessa elever. Arbetet inleds med en teorigenomgång där jag främst går igenom de utmärkande dragen hos barn med Asperger syndrom. Där går jag också bl a igenom orsaker till Asperger och diagn...

  5. Reactors

    CERN Document Server

    International Electrotechnical Commission. Geneva

    1988-01-01

    This standard applies to the following types of reactors: shunt reactors, current-limiting reactors including neutral-earthing reactors, damping reactors, tuning (filter) reactors, earthing transformers (neutral couplers), arc-suppression reactors, smoothing reactors, with the exception of the following reactors: small reactors with a rating generally less than 2 kvar single-phase and 10 kvar three-phase, reactors for special purposes such as high-frequency line traps or reactors mounted on rolling stock.

  6. Rodenticides in British barn owls.

    Science.gov (United States)

    Newton, I; Wyllie, I; Freestone, P

    1990-01-01

    Out of 145 Barn Owls found dead through accidents (66%), starvation (32%), shooting (2%) and poisoning (Owls for successive periods of 1, 3 and 6 days. All six owls fed on difenacoum-dosed mice survived all three treatments, in which up to an estimated 101.7 microg of difenacoum was consumed, and the coagulation times of their blood returned to near normal in less than 5-23 days. Four of the six owls fed on brodifacoum-dosed mice died 6-17 days after the 1-day treatment, but the survivors also survived the 3-day and 6-day treatments. Those that died had each eaten 3 mice, with a combined weight of about 105g and a total brodifacoum content of about 46.07 microg, which was equivalent to a dose of 0.150-0.182 mg kg(-1) of owl body weight. After death these owls had 0.63-1.25 micro g(-1) of brodifacoum in their livers. Blood from the survivors would not coagulate at 9 days post-treatment, but did so at 16 days in one bird and between 38 and 78 days in the other. It is concluded that: (1) Barn Owls in Britain are now widely exposed to second-generation rodenticides; (2) not all owls exposed to these chemicals are likely to receive a lethal dose; (3) brodifacoum is more toxic to owls than difenacoum; and (4) while there is yet no evidence that rodenticides have had any appreciable effect on Barn Owl populations in Britain, further monitoring of residue levels and population trends in desirable.

  7. Til forsvar for barns spontane lek

    Directory of Open Access Journals (Sweden)

    Einar Sundsdal

    2015-04-01

    Full Text Available Barndommens far, Jean-Jacques Rousseau (1712-1778, og senere, barnehagens grunnlegger, Friedrich Frøbel (1782-1852, var begge opptatt av barndom og barns mulighet til å tape tid. Dette ble betegnet som negativ pedagogikk og innebar blant annet at barn skulle fordrive tiden med det som passet for barn: lek. Barna skulle få holde på for seg selv, voksne skulle ikke bedrive undervisning, men la barn oppdage verden selv. Disse tankene har vært sentrale for vår moderne forestilling om barndom, og de har vært premissgivende for Barnekonvensjonen som slår fast at alle barn har rett til å leke. Også i dag har leken en sentral posisjon når vi snakker om barndom, men nå knyttes den til en forestilling om å vinne tid. Barn blir nå skjøvet fremover slik at de ikke skal kaste bort tiden - tape tiden - men utnytte den mest mulig effektivt med tanke på et fremtidig resultat. Denne logikken har bidratt til at FN i 2013 gikk ut og advarte om at barns rett til lek er truet. I denne artikkelen vil vi forfølge FNs forsvar for barns spontane lek. Vi vil gjøre dette blant annet ved å vise at lekens egenverdi står stadig sterkere innen en rekke forskningstradisjoner.

  8. Behandlas barn olika? : Smärtskattning på barn efter skoliosoperation

    OpenAIRE

    Karlsson, Linda; Zetterlund, Martin

    2010-01-01

    Inledning: Postoperativ smärta hos barn är fortfarande ett problem trots förbättrade arbetsrutiner och smärtbehandling. Smärtskattning på barn och speciellt barn med kognitiva nedsättningar kräver att sjuksköterskorna har kunskap om tillgängliga smärtskattningsinstrument. På så vis ges alla barn möjlighet att smärtskattas. Syfte: Att undersöka hur ofta sjuksköterskor smärtskattar barn som opereras för skolios postoperativt. Design: En retrospektiv studie. Metod: Journalgranskningen genomförde...

  9. Reactor

    Science.gov (United States)

    Evans, Robert M.

    1976-10-05

    1. A neutronic reactor having a moderator, coolant tubes traversing the moderator from an inlet end to an outlet end, bodies of material fissionable by neutrons of thermal energy disposed within the coolant tubes, and means for circulating water through said coolant tubes characterized by the improved construction wherein the coolant tubes are constructed of aluminum having an outer diameter of 1.729 inches and a wall thickness of 0.059 inch, and the means for circulating a liquid coolant through the tubes includes a source of water at a pressure of approximately 350 pounds per square inch connected to the inlet end of the tubes, and said construction including a pressure reducing orifice disposed at the inlet ends of the tubes reducing the pressure of the water by approximately 150 pounds per square inch.

  10. A survey of Italian compost dairy barns

    Directory of Open Access Journals (Sweden)

    Lorenzo Leso

    2013-12-01

    Full Text Available Compost-bedded pack barns (CBPB, generally known as compost dairy barns, are alternative housing systems for dairy cows. In these barns, the whole surface of the resting area is covered with a deepbedded pack that is frequently stirred in order to incorporate fresh manure into the pack and to enhance the evaporation of water. Experiences with CBPB for dairy cows are reported in literature from the US, Israel, the Netherlands and Austria. Potential advantages of these housing systems regard animal welfare and manure management. Since 2006, this housing system has been widely applied in Italy. However, there is still little scientific knowledge available about Italian CBPB. This study aims to describe the housing system, assess producers’ satisfaction and measure performance of dairy cows housed in CBPB. Ten commercial dairy farms in northern Italy were involved in the study. All pens in each farm were surveyed to determine the total available surface area, bedded area and pack depth. A questionnaire was submitted to each farm manager in order to investigate management practices, labour requirement, amount of bedding materials used and producers’ satisfaction. The temperature of the bedded pack was measured in summer and in winter. Data from the Italian Dairy Association were collected for each herd over a period of one year (from September 2011 to September 2012. In the barns involved in the study, the average total available area was 10.9 m2/cow and the average pack area was 6.7 m2/cow. The bedded pack was aerated 1.4 times per day.The most commonly used bedding material in these farms was dry sawdust. The consumption of bedding materials was 8.1 m3/cow per year. A tendency towards inverse correlation was found between the space per cow and the amount of bedding needed per cow (R2=0.395; P=0.051. Operations related to pack management required 4.1 hours of labour per cow per year. A direct relationship was found between the bedded area space

  11. Barn og unge i det nye medielandskapet

    OpenAIRE

    Basmadjian, Elias

    2014-01-01

    Denne masteroppgaven tar for seg hvordan den digitale utviklingen fører til utfordringer i samfunnet. Gjennom å drøfte begrepet mediedanning tar den for seg hvordan denne utviklingen fører til at dagens barn og unge som blir født inn og vokser opp i et samfunn som er grunnleggende annerledes enn for bare noen år siden. Ettersom tilgangen på digitale nyvinninger og sosiale medier er «allestedsnærværende» stiller dette også krav til deres evne til å forstå og bruke denne teknologien på en bærek...

  12. Pulmonary effects of exposure to pig barn air

    Directory of Open Access Journals (Sweden)

    Singh Baljit

    2006-06-01

    Full Text Available Abstract Swine production has undergone rapid transformation from family owned operation to a large scale industrial enterprise. Since increasing number of pigs are reared on a large scale in confined buildings, some of the swine barn workers may be employed to work eight hours per day. Swine barn workers suffer from higher incidences of impaired air flow and lung inflammation, which is attributed to high intensity and interrupted exposures to pig barn air. The air in these barns contains gases, dust, microbes and endotoxin with endotoxin being the major suspect as the cause of lung dysfunction. This review attempts to describe the current state of knowledge of incidences and mechanisms of pulmonary dysfunction following exposure to the barn air.

  13. 22 Matt Barnes 再出发

    Institute of Scientific and Technical Information of China (English)

    Husky

    2008-01-01

    太阳队·前锋·201厘米·28岁上季成绩·6.7分·42.3%投篮·4.4篮板如果你是我们的忠实读者,就会发现巴恩斯(Matt Barnes)在过去13个月内已经第三度登上这个单元了。究竟,这位生涯单季平均得分从没超过10分的球员,有何值得我们一再报导的地方呢?

  14. Marknadsföring till barn : Etik och ansvar

    OpenAIRE

    Haire, Miranda

    2013-01-01

    Detta examensarbete handlar om marknadsföring till barn, samt etiken och ansvaret kring ämnet. Ansvaret ligger mestadels hos marknadsförarna och föräldrarna. Marknadsföring till barn bedöms strängare av juridiska bestämmelser än vanlig marknadsföring, eftersom att barn är mera mottagliga och inte har samma erfarenhet som vuxna. Syftet med detta examensarbete är att få fram allmänt om marknadsföring till barn, etiska frågeställningar, samhällsansvaret samt ansvaret hos marknadsförare, föräldra...

  15. Otoacoustic interrelationships of the barn owl

    Science.gov (United States)

    Bergevin, Christopher; Manley, Geoffrey A.; Köppl, Christine

    2015-12-01

    Significant debate still exists about the biophysical mechanisms at work in otoacoustic emission (OAE) generation and how such may differ between mammals and non-mammals given gross morphological differences (e.g., existence of basilar membrane traveling waves, degree of tectorial membrane coupling). To further elucidate general principles at work, we examined the barn owl for interrelationships between spontaneous emissions (SOAEs) and those evoked using a single tone (SFOAEs). First, most ears exhibited SOAEs as a stable periodic `rippling' whose peak-to-peak spacing was relatively constant (˜0.4 kHz). Some ears showed substantially larger narrowband peaks, although their statistical distributions were highly noisy. Second, significant interactions between a low-level tone and SOAE activity were observed via an interference pattern as the tone frequency was swept. Using a suppression paradigm to extract SFOAEs as the residual, the magnitude exhibited a stable pattern of peaks and valleys unique to each ear. Third, SFOAE phase exhibited significant accumulation as frequency was swept, with a phase-gradient delay of approximately 2 ms that was constant across frequency. The amount of SFOAE phase accumulation between adjacent SOAE peaks tended to cluster about an integral number of cycles, as previously observed for humans. Taken together, our data suggest that the principles underlying how active hair cells work together (e.g., entrainment, phase coherence) are shared between widely different inner ear morphologies, leading to the generation of OAEs with similar properties.

  16. Adaptation potential of naturally ventilated barns to high temperature extremes: The OptiBarn project

    Science.gov (United States)

    Menz, Christoph

    2016-04-01

    Climate change interferes with various aspects of the socio-economic system. One important aspect is its influence on animal husbandry, especially dairy faming. Dairy cows are usually kept in naturally ventilated barns (NVBs) which are particular vulnerable to extreme events due to their low adaptation capabilities. An effective adaptation to high outdoor temperatures for example, is only possible under certain wind and humidity conditions. High temperature extremes are expected to increase in number and strength under climate change. To assess the impact of this change on NVBs and dairy cows also the changes in wind and humidity needs to be considered. Hence we need to consider the multivariate structure of future temperature extremes. The OptiBarn project aims to develop sustainable adaptation strategies for dairy housings under climate change for Europe, by considering the multivariate structure of high temperature extremes. In a first step we identify various multivariate high temperature extremes for three core regions in Europe. With respect to dairy cows in NVBs we will focus on the wind and humidity field during high temperature events. In a second step we will use the CORDEX-EUR-11 ensemble to evaluate the capability of the RCMs to model such events and assess their future change potential. By transferring the outdoor conditions to indoor climate and animal wellbeing the results of this assessment can be used to develop technical, architectural and animal specific adaptation strategies for high temperature extremes.

  17. REDESIGN OF COMMONLY USED TOBACCO CURING BARNS IN ZIMBABWE FOR INCREASED ENERGY EFFICIENCY

    Directory of Open Access Journals (Sweden)

    SPECIAL MUSONI

    2013-03-01

    Full Text Available In Zimbabwe two types of barns are commonly used for tobacco curing, namely the traditional and Rocket barns. The traditional barn and the Rocket Barn loose 98.5% and 55.6% of the energy supplied respectively. The latter is 43.6% more thermally efficient than the traditional barn. There is, however, potential of increasing the energy efficiency of both barns. In this study, a design that incorporates structural changes to reduce heat loss as well as recovery of heat was developed. The design is a combination of commercially available components, and allows for ventilation heat re-use and increased heat transfer from furnace ducts to the drying chamber. The structure was found to be 54.7% more thermally efficient than the Rocket barn and 74.2% more efficient than the traditional barn. The new design needs to be field-tested so that it can be adopted by tobacco farmers.

  18. MBsums. A Mathematica package for the representation of Mellin-Barnes integrals by multiple sums

    Energy Technology Data Exchange (ETDEWEB)

    Ochman, Michal; Riemann, Tord

    2015-11-15

    Feynman integrals may be represented by the Mathematica package AMBRE and MB as multiple Mellin-Barnes integrals. With the Mathematica package MBsums we transform these Mellin-Barnes integrals into multiple sums.

  19. Barns psykosociala hälsa i skolmiljö

    OpenAIRE

    Nysand, Maria; Hannus, Martina; Jaakkola, Riina

    2010-01-01

    Vårt examensarbete ingår i ett delprojekt i KLUCK2 och syftar till att undersöka skolan som fysisk och psykosocial miljö. Ämnesområdet för examensarbetet är barns psyko-sociala hälsa i relation till mobbning, stress och trivsel i skolmiljö. Syftet med vår studie är att undersöka vad som uppmärksammas i ny forskning kring barns psykosociala hälsa och vilka faktorer som framkallar psykosocial ohälsa eller hälsa hos barn i skolan. Detta examensarbete genomförs som en litteraturstudie. Under...

  20. Design methodology for the robotic milking barn : modelling, simulation, validation and optimization

    NARCIS (Netherlands)

    Halachmi, I.

    1999-01-01

    The traditional barn design is a milking parlour oriented. To integrate a milking robot the barn should be redesigned according to the robotic milking concept. The entire system (barn design, feeding and cow-traffic routines, management practices) should encourage 'voluntary milking', i.e., it shoul

  1. Bedded pack barns for dairy cattle in the Netherlands

    NARCIS (Netherlands)

    Galama, P.J.; Boer, de H.C.; Dooren, van H.J.C.; Ouweltjes, W.; Poelarends, J.J.; Driehuis, F.

    2014-01-01

    The bedded pack barn offers good perspective on animal welfare, animal health and public perception, but has disadvantages in terms of mineral management (nitrogen losses and fertilising value) and the presence of TAS (Thermophilic Aerobic Spore formers). Bedded packs with compost have a too high am

  2. Spatial and Nonspatial Escape Strategies in the Barnes Maze

    Science.gov (United States)

    Harrison, Fiona E.; Reiserer, Randall S.; Tomarken, Andrew J.; McDonald, Michael P.

    2006-01-01

    The Barnes maze is a spatial memory task that requires subjects to learn the position of a hole that can be used to escape the brightly lit, open surface of the maze. Two experiments assessed the relative importance of spatial (extra-maze) versus proximal visible cues in solving the maze. In Experiment 1, four groups of mice were trained either…

  3. Barn music at St Donat's castle / Philip Gross

    Index Scriptorium Estoniae

    Gross, Philip, 1952-

    2011-01-01

    Muusikafestivalist "Vale of Glamorgan", mis oli 2010. a. pühendatud Arvo Pärdile. Eesti kammermuusikaansambli Resonabilis kavas oli ka festivali tellimusel valminud uelsi helilooja Gareth Peredur Churchilli "Vocable", mille teksti kirjutas Philip Gross. Festivalikontsertide muljeid leiab Grossi luuletsüklis "Barn music" (avaldatud samas ajakirjanumbris, lk. 42-43)

  4. Evaluating multiloop Feynman integrals by Mellin-Barnes representation

    CERN Document Server

    Smirnov, V A

    2004-01-01

    The status of analytical evaluation of double and triple box diagrams is characterized. The method of Mellin-Barnes representation as a tool to evaluate master integrals in these problems is advocated. New MB representations for massive on-shell double boxes with general powers of propagators are presented.

  5. Barnes maze testing strategies with small and large rodent models.

    Science.gov (United States)

    Rosenfeld, Cheryl S; Ferguson, Sherry A

    2014-02-26

    Spatial learning and memory of laboratory rodents is often assessed via navigational ability in mazes, most popular of which are the water and dry-land (Barnes) mazes. Improved performance over sessions or trials is thought to reflect learning and memory of the escape cage/platform location. Considered less stressful than water mazes, the Barnes maze is a relatively simple design of a circular platform top with several holes equally spaced around the perimeter edge. All but one of the holes are false-bottomed or blind-ending, while one leads to an escape cage. Mildly aversive stimuli (e.g. bright overhead lights) provide motivation to locate the escape cage. Latency to locate the escape cage can be measured during the session; however, additional endpoints typically require video recording. From those video recordings, use of automated tracking software can generate a variety of endpoints that are similar to those produced in water mazes (e.g. distance traveled, velocity/speed, time spent in the correct quadrant, time spent moving/resting, and confirmation of latency). Type of search strategy (i.e. random, serial, or direct) can be categorized as well. Barnes maze construction and testing methodologies can differ for small rodents, such as mice, and large rodents, such as rats. For example, while extra-maze cues are effective for rats, smaller wild rodents may require intra-maze cues with a visual barrier around the maze. Appropriate stimuli must be identified which motivate the rodent to locate the escape cage. Both Barnes and water mazes can be time consuming as 4-7 test trials are typically required to detect improved learning and memory performance (e.g. shorter latencies or path lengths to locate the escape platform or cage) and/or differences between experimental groups. Even so, the Barnes maze is a widely employed behavioral assessment measuring spatial navigational abilities and their potential disruption by genetic, neurobehavioral manipulations, or drug

  6. Drinking and Cleaning Water Use in a Dairy Cow Barn

    Directory of Open Access Journals (Sweden)

    Michael Krauß

    2016-07-01

    Full Text Available Water is used in dairy farming for producing feed, watering the animals, and cleaning and disinfecting barns and equipment. The objective of this study was to investigate the drinking and cleaning water use in a dairy cow barn. The water use was measured on a well-managed commercial dairy farm in North-East Germany. Thirty-eight water meters were installed in a barn with 176 cows and two milking systems (an automatic milking system and a herringbone parlour. Their counts were logged hourly over 806 days. On average, the cows in the automatic milking system used 91.1 (SD 14.3 L drinking water per cow per day, while those in the herringbone parlour used 54.4 (SD 5.3 L per cow per day. The cows drink most of the water during the hours of (natural and artificial light in the barn. Previously published regression functions of drinking water intake of the cows were reviewed and a new regression function based on the ambient temperature and the milk yield was developed (drinking water intake (L per cow per day = −27.937 + 0.49 × mean temperature + 3.15 × milk yield (R2 = 0.67. The cleaning water demand had a mean of 28.6 (SD 14.8 L per cow per day in the automatic milking system, and a mean of 33.8 (SD 14.1 L per cow per day in the herringbone parlour. These findings show that the total technical water use in the barn makes only a minor contribution to water use in dairy farming compared with the water use for feed production.

  7. John Dewey's Socially Instrumental Practice at the Barnes Foundation and the Role of "Transferred Values" in Aesthetic Experience

    Science.gov (United States)

    Johnson, Margaret Hess

    2012-01-01

    When Albert Barnes established an art education program at the Barnes Foundation in 1924, he asked John Dewey to become the first president and director of education. Barnes and Dewey enjoyed a sustained and fruitful relationship with regard to aesthetic experience and scientific theory as applied to education. Barnes and Dewey shared a serious…

  8. Nuclear Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hogerton, John

    1964-01-01

    This pamphlet describes how reactors work; discusses reactor design; describes research, teaching, and materials testing reactors; production reactors; reactors for electric power generation; reactors for supply heat; reactors for propulsion; reactors for space; reactor safety; and reactors of tomorrow. The appendix discusses characteristics of U.S. civilian power reactor concepts and lists some of the U.S. reactor power projects, with location, type, capacity, owner, and startup date.

  9. Mellin-Barnes Representation of the Topological String

    CERN Document Server

    Krefl, Daniel

    2015-01-01

    We invoke integrals of Mellin-Barnes type to analytically continue the Gopakumar-Vafa resummation of the topological string free energy in the string coupling constant, leading to additional non-perturbative terms. We also discuss in a similar manner the refined and Nekrasov-Shatashvili limit version thereof. The derivation is straight-forward and essentially boils down to taking residue. This allows us to confirm some related conjectures in the literature at tree-level.

  10. Det raske og det syge nyfødte barn

    DEFF Research Database (Denmark)

    Peitersen, Birgit; Pedersen, Pernille; Pryds, Ole

    NEONATOLOGI er en lære- og håndbog om det raske og det syge nyfødte barn. Den henvender sig især til sundhedspersonale, der arbejder med nyfødte børn – herunder sygeplejersker, jordemødre og medicinske kandidater. I de første kapitler gennemgås almene emner som fosterets udvikling, muligheder...

  11. Annual Report of Monitoring at Barnes, Kansas, in 2012

    Energy Technology Data Exchange (ETDEWEB)

    LaFreniere, Lorraine M. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2013-06-01

    Barnes, Kansas, is a small rural community (population approximately 150) located in Washington County, in north-central Kansas (Figure 1.1). Barnes is located in Section 9, Township 4 South, Range 5 East, at approximate latitude 39°43'0'' north and longitude 96°52'25'' west (USGS 1968). The city lies in a transition zone between the Flint Hills and the glaciated region. The area’s topography consists of gently sloping hills of Pleistocene loess (< 20 ft) overlying a shale unit and interbedded shale, limestone, and siltstone of the Permian Chase Group. Groundwater for the public water supply is obtained from wells PWS2 and PWS3 at reported depths of 155 ft and 160 ft, respectively, located in the northwestern portion of the city. The water is produced from the bedrock aquifer of the Chase Group. Section 2 summarizes the hydrogeologic conceptual site model. This report summarizes findings for groundwater inspection in Barnes.

  12. Temperature distribution of air source heat pump barn with different air flow

    Science.gov (United States)

    He, X.; Li, J. C.; Zhao, G. Q.

    2016-08-01

    There are two type of airflow form in tobacco barn, one is air rising, the other is air falling. They are different in the structure layout and working principle, which affect the tobacco barn in the distribution of temperature field and velocity distribution. In order to compare the temperature and air distribution of the two, thereby obtain a tobacco barn whose temperature field and velocity distribution are more uniform. Taking the air source heat pump tobacco barn as the investigated subject and establishing relevant mathematical model, the thermodynamics of the two type of curing barn was analysed and compared based on Fluent. Provide a reasonable evidence for chamber arrangement and selection of outlet for air source heat pump tobacco barn.

  13. Compost bedded pack dairy barn management, performance, and producer satisfaction.

    Science.gov (United States)

    Black, R A; Taraba, J L; Day, G B; Damasceno, F A; Bewley, J M

    2013-01-01

    The objective of the research was to characterize herd performance, producer satisfaction and recommendations, and management practices used by compost bedded pack (CBP) managers in Kentucky (42 farms and 47 CBP facilities). Farms were visited between October 2010 and March 2011. A random selection of cows housed solely in the CBP were scored for locomotion and hygiene. Changes in monthly Dairy Herd Improvement Association performance records, including milk production, SCC, reproductive performance, and daily bulk-tank somatic cell count after moving into the CBP were analyzed using the MIXED procedure of SAS (SAS 9.3; SAS Institute Inc., Cary, NC). The GLM procedure of SAS (SAS 9.3) was used to develop models to describe CBP moisture, CBP temperature at 20.3 cm, and mean herd hygiene. Producers provided 9.0 ± 2.2 m2 of pack space per cow (n = 44). Barns constructed with an attached feed alley cost $1,051 ± 407 per cow (n = 40). Barns constructed without an attached feed alley cost $493 ± 196 per cow (n = 13). Kiln-dried shavings required 0.05 ± 0.04 m3 of bedding per cow per day (n = 15). Green shavings required 0.07 ± 0.06 m3 of bedding per cow per day (n = 12). The most-frequently cited benefits of the CBP included cow comfort (n = 28), cow cleanliness (n = 14), and the low-maintenance nature of the system (n = 10). Increased stirring frequency, stirring depth, and ambient temperature increased pack temperature, measured at 20.3 cm below the CBP surface. Increased stirring depth, pasture-adjusted space per cow, and drying rate decreased CBP moisture. Mean herd locomotion and hygiene scores were 1.5 ± 0.3 (n = 34) and 2.2 ± 0.4 (n = 34), respectively. Increased 20.3-cm depth CBP temperature and ambient temperatures improved mean herd hygiene. Bulk-tank somatic cell count decreased from the year before to the year after moving into the CBP barn (323,692 ± 7,301 vs. 252,859 ± 7,112 cells/mL, respectively) for farms using the CBP barn as the primary

  14. EMDR-behandling  : Barns och ungdomars upplevelser en kvalitetssäkringsstudie 

    OpenAIRE

    Fredin, Ingela

    2005-01-01

    Föreliggande studie är dels ett led i att kvalitetssäkra EMDR (Eye Movement Desensitization and Reprocessing) som behandlingsmetod för barn och ungdomar och dels att utröna om behandlingen bidragit till ett förbättrat mående. EMDR som behandlingsmetod för barn och ungdomar har stöd i kontrollerade studier, men ytterligare forskning behövs. I den här studien deltog åtta barn och ungdomar med varierande diagnoser, vilka fått EMDR-behandling i barn- och ungdomspsykiatrisk öppenvård. Behandlingen...

  15. Designing the optimal robotic milking barn, Part 1: Quantifying facility usage

    NARCIS (Netherlands)

    Halachmi, I.; Metz, J.H.M.; Maltz, E.; Dijkhuizen, A.A.; Speelman, L.

    2000-01-01

    The aim of this paper is to explore the stochastic nature of the usage of facilities in a robotic milking barn, independent of the barn layout. It presents experimental data obtained by monitoring 10 dairy cows over a period of 18 days. To minimize restrictions to the access of cows to the facilitie

  16. Social interactions of dairy cows introduced postpartally to a separated barn section - pilot study

    DEFF Research Database (Denmark)

    Burow, Elke; Nielsen, Tine Rousing; Halekoh, Ulrich;

    2009-01-01

    The hypothesis of reduced social activity of early lactating dairy cows when transferred postpartally to a separated barn section (S, group size 9.3 SD 2.1) vs. to a barn section of the main lactating herd (H, group size 130.1 SD 57.9) was tested. Social interactions of 12 cows in S and 14 cows i...

  17. Designing the optimal robotic milking barn, part 2: behaviour-based simulation

    NARCIS (Netherlands)

    Halachmi, I.

    2000-01-01

    Robotic milking affects factors that determine the barn layout, such as cow behaviour, farm routine, feeding procedure and management practices. As there is hardly any experience with robotic barns, and each farmer has his own management attitude, depending on his personality and local conditions; t

  18. Unheralded Historian: Mary Sheldon Barnes and Primary Source Material in History Books

    Science.gov (United States)

    Chisholm, James A., Jr.

    2013-01-01

    In the latter part of the nineteenth century, Mary Sheldon Barnes emerged as a leading historical methods professor and history textbook author. Although men dominated the field, she wrote several articles and books alone or with her husband Earl Barnes about primary source materials and teaching. She lived during an era in United States history…

  19. Designing the optimal robotic milking barn by applying a queuing network approach

    NARCIS (Netherlands)

    Halachmi, I.; Adan, I.J.B.F.; Wald, van der J.; Beek, van P.; Heesterbeek, J.A.P.

    2003-01-01

    The design of various conventional dairy barns is based on centuries of experience, but there is hardly any experience with robotic milking barns (RMB). Furthermore, as each farmer has his own management practices, the optimal layout is `site dependent¿. A new universally applicable design methodolo

  20. Barnes Ice Cap South Dome Trilateration Net Survey Data 1970-1984

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Barnes Ice Cap data set contains survey measurements of a network of 43 stakes along a 10 km flow line on the northeast flank of the south dome of the Barnes Ice...

  1. Barns kommunikasjon med ulike typer kart - en progressiv tilnærming til kartlesing

    Directory of Open Access Journals (Sweden)

    Trine Bjerva

    2011-11-01

    Full Text Available Utgangspunktet for denne studien er en erkjennelse av hvor vanskelig det kan være for barn å samhandle med det symbolske kartet. Hovedmålet for prosjektet var å utvikle sikrere viten om hvordan barn kommuniserer med ulike typer kart. Det er utarbeidet en modell (Bjerva, Græsli, & Sigurjónsson, 2010 som viser hvordan vi kan utvikle ferdigheten kartlesing hos barn. Vi har undersøkt 106 barn i alderen 3 til 12 år om hvordan de mestrer direkte representasjoner (detaljfoto og perspektiv representasjoner (håndtegnet skråkart. Forskningsdesignet har en økologisk tilnærming hvor datainnsamlingen har foregått i terrenget. Resultatene indikerer at selv små barn mestrer antatt kompliserte oppgaver når de blir presentert for enkle hjelpemidler.

  2. New four-dimensional integrals by Mellin-Barnes transform

    CERN Document Server

    Allendes, Pedro; Kondrashuk, Igor; Cuello, Eduardo A Notte

    2009-01-01

    This paper is devoted to the calculation by Mellin-Barnes transform of a especial class of integrals. It contains double integrals in the position space in d = 4-2e dimensions, where e is parameter of dimensional regularization. These integrals contribute to the effective action of the N = 4 supersymmetric Yang-Mills theory. The integrand is a fraction in which the numerator is a logarithm of ratio of spacetime intervals, and the denominator is the product of powers of spacetime intervals. According to the method developed in the previous papers, in order to make use of the uniqueness technique for one of two integrations, we shift exponents in powers in the denominator of integrands by some multiples of e. As the next step, the second integration in the position space is done by Mellin-Barnes transform. For normalizing procedure, we reproduce first the known result obtained earlier by Gegenbauer polynomial technique. Then, we make another shift of exponents in powers in the denominator to create the logarith...

  3. Annual report of monitoring at Barnes, Kansas, in 2010.

    Energy Technology Data Exchange (ETDEWEB)

    LaFreniere, L. M. (Environmental Science Division)

    2011-05-25

    The Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) operated a grain storage facility at Barnes, Kansas, in 1949-1974. Carbon tetrachloride contamination was initially detected in 1986 in the town's public water supply wells. In 2006-2007, the CCC/USDA conducted a comprehensive targeted investigation at and near its former property in Barnes to characterize this contamination. Those results were reported previously (Argonne 2008a). The results of that investigation indicated that carbon tetrachloride contamination is present in groundwater at low to moderate levels in the vicinity of the former CCC/USDA grain storage facility. Information obtained during the 2006-2007 investigation also indicated that at least one other potential source might have contributed to the groundwater contaminant plume (Argonne 2008a). The former agriculture building owned by the local school district, located immediately east of well PWS3, is also a potential source of the contamination. In November 2007, the CCC/USDA began periodic groundwater monitoring at Barnes. The monitoring is being conducted on behalf of the CCC/USDA by Argonne National Laboratory, under the direction of the Kansas Department of Health and Environment (KDHE). The objective is to monitor the carbon tetrachloride contamination identified in the groundwater at Barnes. Through 2010, sampling was conducted in a network of 28 individual monitoring wells (at 19 distinct locations), 2 public water supply wells, and 1 private well (Figure 1.1). The results of the 2006-2007 targeted investigation and the subsequent monitoring events (Argonne 2008a-d, 2009a,b, 2010) demonstrated the presence of carbon tetrachloride contamination in groundwater at levels exceeding the KDHE Tier 2 risk-based screening level (RBSL) of 5.0 {micro}g/L for this compound. The contaminant plume appears to extend from the former CCC/USDA property northwestward, toward the Barnes public water supply wells. Long

  4. H Reactor

    Data.gov (United States)

    Federal Laboratory Consortium — The H Reactor was the first reactor to be built at Hanford after World War II.It became operational in October of 1949, and represented the fourth nuclear reactor on...

  5. Analysis of Temperature and Humidity Field in a New Bulk Tobacco Curing Barn Based on CFD

    Science.gov (United States)

    Bai, Zhipeng; Guo, Duoduo; Li, Shoucang; Hu, Yaohua

    2017-01-01

    A new structure bulk tobacco curing barn was presented. To study the temperature and humidity field in the new structure tobacco curing barn, a 3D transient computational fluid dynamics (CFD) model was developed using porous medium, species transport, κ-ε turbulence and discrete phase models. The CFD results demonstrated that (1) the temperature and relative humidity predictions were validated by the experimental results, and comparison of simulation results with experimental data showed a fairly close agreement; (2) the temperature of the bottom and inlet area was higher than the top and outlet area, and water vapor concentrated on the top and outlet area in the barn; (3) tobacco loading density and thickness of tobacco leaves had an explicit effect on the temperature distributions in the barn. PMID:28146128

  6. Chicken barn climate and hazardous volatile compounds control using simple linear regression and PID

    Science.gov (United States)

    Abdullah, A. H.; Bakar, M. A. A.; Shukor, S. A. A.; Saad, F. S. A.; Kamis, M. S.; Mustafa, M. H.; Khalid, N. S.

    2016-07-01

    The hazardous volatile compounds from chicken manure in chicken barn are potentially to be a health threat to the farm animals and workers. Ammonia (NH3) and hydrogen sulphide (H2S) produced in chicken barn are influenced by climate changes. The Electronic Nose (e-nose) is used for the barn's air, temperature and humidity data sampling. Simple Linear Regression is used to identify the correlation between temperature-humidity, humidity-ammonia and ammonia-hydrogen sulphide. MATLAB Simulink software was used for the sample data analysis using PID controller. Results shows that the performance of PID controller using the Ziegler-Nichols technique can improve the system controller to control climate in chicken barn.

  7. Improvement of directionality and sound-localization by internal ear coupling in barn owls

    DEFF Research Database (Denmark)

    Wagner, Hermann; Christensen-Dalsgaard, Jakob; Kettler, Lutz

    Mark Konishi was one of the first to quantify sound-localization capabilities in barn owls. He showed that frequencies between 3 and 10 kHz underlie precise sound localization in these birds, and that they derive spatial information from processing interaural time and interaural level differences....... However, despite intensive research during the last 40 years it is still unclear whether and how internal ear coupling contributes to sound localization in the barn owl. Here we investigated ear directionality in anesthetized birds with the help of laser vibrometry. Care was taken that anesthesia...... time difference in the low-frequency range, barn owls hesitate to approach prey or turn their heads when only low-frequency auditory information is present in a stimulus they receive. Thus, the barn-owl's sound localization system seems to be adapted to work best in frequency ranges where interaural...

  8. Evaluating two-loop massive operator matrix elements with Mellin-Barnes integrals

    Energy Technology Data Exchange (ETDEWEB)

    Bierenbaum, I.; Bluemlein, J.; Klein, S.

    2006-07-15

    We calculate massive 5-propagator 2-loop integrals for operator matrix elements in the light-cone expansion, using Mellin-Barnes techniques and representations through generalized hypergeometric functions. (Orig.)

  9. Reliable low-cost devices for monitoring ammonia concentrations and emissions in naturally ventilated dairy barns.

    Science.gov (United States)

    Wang, Xiang; Ndegwa, Pius M; Joo, HungSoo; Neerackal, George M; Harrison, Joseph H; Stöckle, Claudio O; Liu, Heping

    2016-01-01

    This research investigated the use of two relatively cost-effective devices for determining NH3 concentrations in naturally ventilated (NV) dairy barns including an Ogawa passive sampler (Ogawa) and a passive flux sampler (PFS). These samplers were deployed adjacent to sampling ports of a photoacoustic infrared multigas spectroscope (INNOVA), in a NV dairy barn. A 3-day deployment period was deemed suitable for both passive samplers. The correlations between concentrations determined with the passive samplers and the INNOVA were statistically significant (r = 0.93 for Ogawa and 0.88 for PFS). Compared with reference measurements, Ogawa overestimated NH3 concentrations in the barn by ∼ 14%, while PFS underestimated NH3 concentrations by ∼ 41%. Barn NH3 emission factors per animal unit (20.6-21.2 g d(-1) AU(-1)) based on the two passive samplers, after calibration, were similar to those obtained with the reference method and were within the range of values reported in literature.

  10. Rehabilitation of farmhouses and barns: limits of salt content

    Science.gov (United States)

    De Clercq, Hilde; Godts, Sebastiaan

    2016-09-01

    The rehabilitation of historic buildings is a practice that aims to turn a historic property into a state of contemporary comfort for private or commercial use, while preserving its historic, architectural and cultural value, respecting items of authenticity, compatibility and sustainability. What once was a modest use of locally fired brick and mortar has become the subject of ambitious rehabilitation campaigns conforming to the rules of comfort and hygiene of the twenty-first century. A pre-investigation concerning the diagnosis of damage phenomena and the risk assessment of interventions is a crucial aspect for the success of a restoration campaign. The question of "How to optimally preserve a monument within its current conditions" is replaced by "How can a monument optimally perform in the conditions suited to the assigned rehabilitation project". Today historic farms and their surroundings, after being abandoned for several decades, are the subject of different types of private or commercial rehabilitation projects. An example of such a project is the farm "Hof De Pleyne" in Loppem (West-Flanders, Belgium). The project intended to integrate a restaurant kitchen into the former animal barn. The limits of salt content with respect to the desired rehabilitation facilities while respecting safety regulations are presented.

  11. Reactor Physics

    Energy Technology Data Exchange (ETDEWEB)

    Ait Abderrahim, A

    2001-04-01

    The Reactor Physics and MYRRHA Department of SCK-CEN offers expertise in various areas of reactor physics, in particular in neutronics calculations, reactor dosimetry, reactor operation, reactor safety and control and non-destructive analysis of reactor fuel. This expertise is applied in the Department's own research projects in the VENUS critical facility, in the BR1 reactor and in the MYRRHA project (this project aims at designing a prototype Accelerator Driven System). Available expertise is also used in programmes external to the Department such as the reactor pressure steel vessel programme, the BR2 reactor dosimetry, and the preparation and interpretation of irradiation experiments by means of neutron and gamma calculations. The activities of the Fuzzy Logic and Intelligent Technologies in Nuclear Science programme cover several domains outside the department. Progress and achievements in these topical areas in 2000 are summarised.

  12. Reactor safeguards

    CERN Document Server

    Russell, Charles R

    1962-01-01

    Reactor Safeguards provides information for all who are interested in the subject of reactor safeguards. Much of the material is descriptive although some sections are written for the engineer or physicist directly concerned with hazards analysis or site selection problems. The book opens with an introductory chapter on radiation hazards, the construction of nuclear reactors, safety issues, and the operation of nuclear reactors. This is followed by separate chapters that discuss radioactive materials, reactor kinetics, control and safety systems, containment, safety features for water reactor

  13. Reactor operation

    CERN Document Server

    Shaw, J

    2013-01-01

    Reactor Operation covers the theoretical aspects and design information of nuclear reactors. This book is composed of nine chapters that also consider their control, calibration, and experimentation.The opening chapters present the general problems of reactor operation and the principles of reactor control and operation. The succeeding chapters deal with the instrumentation, start-up, pre-commissioning, and physical experiments of nuclear reactors. The remaining chapters are devoted to the control rod calibrations and temperature coefficient measurements in the reactor. These chapters also exp

  14. Characterization of Staphylococcus xylosus isolated from broiler chicken barn bioaerosol.

    Science.gov (United States)

    Vela, Javier; Hildebrandt, Kelsie; Metcalfe, Andrew; Rempel, Heidi; Bittman, Shabtai; Topp, Edward; Diarra, Moussa

    2012-12-01

    In this study we isolated and characterized Staphylococcus xylosus, a coagulase-negative staphylococcal species considered as commensal and one of the prevalent staphylococcal species found in poultry bioaerosol. Isolates were obtained using air samplers and selective phenylethyl alcohol agar for gram-positive bacteria during 35-d periods at different times of the day. A total of 200 colonies were recovered and after basic biochemical tests were performed, presumptive staphylococci were subsequently identified by API Staph strips. A total of 153 (76.5%) staphylococci were found, among which 84 were S. xylosus (46 and 38 isolated inside and outside, respectively). Biofilm formation was observed in 86.9% of S. xylosus isolates, whereas 79.8% of them showed hemolytic activity. There was a strong correlation (92.5%) between biofilm formation and hemolytic activity. All 84 S. xylosus isolates were susceptible to amikacin, ampicillin/sulbactam, chloramphenicol, ciprofloxacin, gentamycin, kanamycin, linezolid, trimethoprim/sulfamethoxazole, and vancomycin. Resistance to nalidixic acid (86.9%), novobiocin (85.7%), penicillin (70.2%), lincomycin (46.4%), oxacillin (42.9%), ampicillin (27.4%), tetracycline (21.4%), erythromycin (11.9%), bacitracin (10.7%), and streptomycin (2.4%) was observed among the isolates. Resistance to tetracycline, lincomycin, erythromycin, and β-lactam antibiotics was occasionally linked to the tetK, linA, ermB, and blaZ genes, respectively. Random amplification of polymorphic DNA results showed similarity of 15 to 99% between isolates collected outside and inside the barn, indicating genetic diversity of these isolates. Our study indicates that characterization of poultry bioaerosol coagulase-negative staphylococcal species such as S. xylosus is necessary for assessing their safety status for both poultry and humans.

  15. Memory Revisited in Julian Barnes's The Sense of an Ending

    Directory of Open Access Journals (Sweden)

    Maricel Oró Piqueras

    2014-02-01

    Full Text Available An accumulation of years brings with it an accumulation of experiences. The revision of such experiences usually becomes more recurrent after retirement, a transition time from one period of life to another and, as such, a time in which we, human beings, have a tendency to take stock of our lives. This is actually one of the main issues present in Julian Barnes's last novel The Sense of an Ending (2011. When the main protagonist, a retired man quite comfortable and contented with his present life, receives an unexpected inheritance from the mother of a girlfriend from his university years, he is forced to track down a part of his life that he had left at the back of his mind a long time ago. As he explains his story, the protagonist and narrator of the novel raises a number of questions related to the quality and function of memory as one gets into old age. He experiments the unreliability of memory and questions to what extent memory is constructed through the remembered emotions that invaded him over that episode of his life rather than through the events as they actually took place. On the other hand, the act of revisiting and revising that specific episode, brings with it feelings of guilt and remorse as the protagonist realises that his past acts were not as noble as he remembered them to be. However, these acts are part of the past and they cannot be changed; thus, another question that the novel raises is how to account for those actions of which one does not feel proud and, more importantly, how to manage those bad memories as one gets older

  16. Analysis of thermal characteristics of electrical wiring for load groups in cattle barns.

    Science.gov (United States)

    Kim, Doo Hyun; Yoo, Sang-Ok; Kim, Sung Chul; Hwang, Dong Kyu

    2015-01-01

    The purpose of the current study is to analyze the thermal characteristics of electrical wirings depending on the number of operating load by connecting four types of electrical wirings that are selected by surveying the conditions for the electric fans, automatic waterers and halogen warm lamps that were installed in cattle barns in different years. The conditions of 64 cattle barns were surveyed and an experimental test was conducted at a cattle barn. The condition-survey covered inappropriate design, construction and misuse of electrical facility, including electrical wiring mostly used, and the mode of load current was evaluated. The survey showed that the mode of load current increased as the installation year of the fans, waterers and halogen lamps became older. Accordingly, the cattle barn manager needed to increase the capacity of the circuit breaker, which promoted the degradation of insulation of the electrical wires' sheath and increased possibility for electrical fires in the long-run. The test showed that the saturation temperature of the wire insulated sheath increased depending on the installation year of the load groups, in case of VCTFK and VFF electric wires, therefore, requiring their careful usage in the cattle barns.

  17. Reactor Neutrinos

    OpenAIRE

    Soo-Bong Kim; Thierry Lasserre; Yifang Wang

    2013-01-01

    We review the status and the results of reactor neutrino experiments. Short-baseline experiments have provided the measurement of the reactor neutrino spectrum, and their interest has been recently revived by the discovery of the reactor antineutrino anomaly, a discrepancy between the reactor neutrino flux state of the art prediction and the measurements at baselines shorter than one kilometer. Middle and long-baseline oscillation experiments at Daya Bay, Double Chooz, and RENO provided very ...

  18. Performance and carcass characteristics of finishing beef cattle managed in a bedded hoop-barn system.

    Science.gov (United States)

    Honeyman, M S; Busby, W D; Lonergan, S M; Johnson, A K; Maxwell, D L; Harmon, J D; Shouse, S C

    2010-08-01

    The use of bedded hoop barns in finishing systems for beef cattle has not been widely researched. In this management system, beef cattle are confined to hoop barns throughout finishing, and bedding is used to absorb animal waste, which results in minimal effluent. The objective of this study was to compare the performance and carcass characteristics of finishing beef steers (n = 1,428) managed in a bedded hoop-barn management system vs. an open-feedlot system with shelter. Six feeding trials were conducted over a 3-yr period. Three trials were conducted during summer-fall and 3 trials were conducted during winter-spring. Crossbred steers were allotted to 3 pens in the hoop-barn system and to 3 pens in the open-lot system (approximately 40 steers per pen in both facility systems). Stocking densities for the steers were 4.65 m(2) per steer in the hoop-barn system and 14.7 m(2) per steer in the open-lot system. The steers were begun on trial weighing 410 and 411 kg (SD = 21), were fed for 102.3 and 103.0 d (SD = 3.8), and were weighed off test at 595 and 602 kg (SD = 21) for the hoop-barn and open-lot systems, respectively. Steer performance measures consisted of ADG, DMI, and G:F. Carcass characteristics were HCW, fat thickness, LM area, KPH percentage, marbling score, USDA yield grade, and USDA quality grade. No year, season, or pen (management system) main effects, or season x management system and year x management system interactions were observed for any of the items measured related to cattle performance or carcass characteristics (P > 0.05). Final mud scores (a subjective evaluation of the amount of soil and manure adhering to the hair coat of the animals) were greater for the steers from the open-lot system compared with those from the hoop-barn system (P < 0.02), suggesting steers in the hoop-barn system carried less mud than steers from the open-lot system. Average daily cornstalk bedding use in the hoop-barn system was 2.3 kg/steer during summer-fall and 2

  19. Low frequency eardrum directionality in the barn owl induced by sound transmission through the interaural canal

    DEFF Research Database (Denmark)

    Kettler, Lutz; Christensen-Dalsgaard, Jakob; Larsen, Ole Næsbye

    2016-01-01

    The middle ears of birds are typically connected by interaural cavities that form a cranial canal. Eardrums coupled in this manner may function as pressure difference receivers rather than pressure receivers. Hereby, the eardrum vibrations become inherently directional. The barn owl also has...... a large interaural canal, but its role in barn owl hearing and specifically in sound localization has been controversial so far. We discuss here existing data and the role of the interaural canal in this species and add a new dataset obtained by laser Doppler vibrometry in a free-field setting....... Significant sound transmission across the interaural canal occurred at low frequencies. The sound transmission induces considerable eardrum directionality in a narrow band from 1.5 to 3.5 kHz. This is below the frequency range used by the barn owl for locating prey, but may conceivably be used for locating...

  20. Low frequency eardrum directionality in the barn owl induced by sound transmission through the interaural canal.

    Science.gov (United States)

    Kettler, Lutz; Christensen-Dalsgaard, Jakob; Larsen, Ole Næsbye; Wagner, Hermann

    2016-10-01

    The middle ears of birds are typically connected by interaural cavities that form a cranial canal. Eardrums coupled in this manner may function as pressure difference receivers rather than pressure receivers. Hereby, the eardrum vibrations become inherently directional. The barn owl also has a large interaural canal, but its role in barn owl hearing and specifically in sound localization has been controversial so far. We discuss here existing data and the role of the interaural canal in this species and add a new dataset obtained by laser Doppler vibrometry in a free-field setting. Significant sound transmission across the interaural canal occurred at low frequencies. The sound transmission induces considerable eardrum directionality in a narrow band from 1.5 to 3.5 kHz. This is below the frequency range used by the barn owl for locating prey, but may conceivably be used for locating conspecific callers.

  1. The Strategy to Increase Women Farmer's Participation in the Program of Village Food Barn in East Java

    Science.gov (United States)

    Yuliatia, Yayuk; Iskaskar, Riyanti

    2016-01-01

    Food Barn Village Programme is one of the government's efforts in achieving household food security which includes four components. The purpose of this study was to develop a strategy to increase women's participation in the Food Barn Village Programme. This research was conducted in three villages in the district of Malang, namely: Village…

  2. Trace metals in primary feathers of the Barn Owl (Tyto alba guttatus) in The Netherlands.

    Science.gov (United States)

    Denneman, W D; Douben, P E

    1993-01-01

    The number of Barn Owls in The Netherlands has been reduced substantially over the last few decades. Death as a result of poisoning seems unlikely, but the pathology of all bird species found dead in The Netherlands between 1975 and 1988 (n = 15 422) shows that 21% of all the birds were contaminated. However, the most important factor responsible for the decline in Barn Owl numbers in The Netherlands has not yet been established. As a part of a new national protection plan for the Barn Owl, the role of heavy metals has been investigated. Concentrations of heavy metals in the primary feathers of the Barn Owl varied according to their position in the wing; especially As, Sb, Fe and Zn whose concentrations depended on the place of the primary feather in the wing and the part of the vane which is used for the monitoring. The HS7 feather vane appears to provide a good estimate, even though the metal concentrations of this feather are always slightly lower than the concentrations in mixed samples of all ten primaries. It is recommended that they are used as a standard. Many factors affect metal concentrations. Increasing levels with age are found, presumably because metals are stored during growth at the end of the feathers as a method of reducing possible harmful effects. No significant correlations were found between the metal concentrations in the organs and those in the feather. Kidney and liver concentrations are always lower than the generally accepted levels for pathological damage of these organs. Even though metal concentrations in Barn Owl feathers are high compared with those reported for other birds in the Netherlands, it is concluded that Barn Owls are not adversely affected by current levels of heavy metal contamination in The Netherlands.

  3. Prey composition modulates exposure risk to anticoagulant rodenticides in a sentinel predator, the barn owl.

    Science.gov (United States)

    Geduhn, Anke; Esther, Alexandra; Schenke, Detlef; Gabriel, Doreen; Jacob, Jens

    2016-02-15

    Worldwide, small rodents are main prey items for many mammalian and avian predators. Some rodent species have pest potential and are managed with anticoagulant rodenticides (ARs). ARs are consumed by target and non-target small mammals and can lead to secondary exposure of predators. The development of appropriate risk mitigation strategies is important and requires detailed knowledge of AR residue pathways. From July 2011 to October 2013 we collected 2397 regurgitated barn owl (Tyto alba) pellets to analyze diet composition of owls on livestock farms in western Germany. 256 of them were fresh pellets that were collected during brodifacoum baiting. Fresh pellets and 742 liver samples of small mammals that were trapped during baiting in the same area were analyzed for residues of ARs. We calculated exposure risk of barn owls to ARs by comparing seasonal diet composition of owls with AR residue patterns in prey species. Risk was highest in autumn, when barn owls increasingly preyed on Apodemus that regularly showed AR residues, sometimes at high concentrations. The major prey species (Microtus spp.) that was consumed most frequently in summer had less potential to contribute to secondary poisoning of owls. There was no effect of AR application on prey composition. We rarely detected ARs in pellets (2 of 256 samples) but 13% of 38 prey individuals in barn owl nests were AR positive and substantiated the expected pathway. AR residues were present in 55% of 11 barn owl carcasses. Fluctuation in non-target small mammal abundance and differences in AR residue exposure patterns in prey species drives exposure risk for barn owls and probably other predators of small mammals. Exposure risk could be minimized through spatial and temporal adaption of AR applications (avoiding long baiting and non-target hot spots at farms) and through selective bait access for target animals.

  4. Representation of spatial and spectro-temporal cues in the midbrain and forebrain of North American barn owls (Tyto furcata pratincola)

    OpenAIRE

    2015-01-01

    The barn owl is a crepuscular and nocturnal bird of prey that relies mainly on its acoustic system for the identification and localization of potential prey. The barn owl is able to localize even faint sounds in a natural environment precisely. Like mammals, barn owls use the interaural time difference (ITD) for the localization of the azimuthal sound source position. In the barn owl’s auditory system, ITD is processed in two separate pathways, the midbrain and forebrain pathways, which are b...

  5. Mellem behovsorientering og regulering - diskurser om det omsorg for det lille barn

    DEFF Research Database (Denmark)

    Pedersen, Oline

    2013-01-01

    En artikel der på baggrund af feltarbejde i den danske sundhedsplejen søger at indfange, hvor diskursen om omsorg for det lille barn befinder sig i spændingsfeltet mellem at regulere barnet eller at følge dets signaler og behov....

  6. Non-planar Feynman diagrams and Mellin-Barnes representations with AMBRE 3.0

    Energy Technology Data Exchange (ETDEWEB)

    Dubovyk, Ievgen [Institute of Electrophysics and Radiation Technologies, Kharkiv (Ukraine); Gluza, Janusz [Univ. of Silesia, Katowice (Poland). Inst. of Physics; Riemann, Tord

    2016-04-15

    We introduce the Mellin-Barnes representation of general Feynman integrals and discuss their evaluation. The Mathematica package AMBRE has been recently extended in order to cover consistently non-planar Feynman integrals with two loops. Prospects for the near future are outlined. This write-up is an introduction to new results which have also been presented elsewhere.

  7. The barn owl wing: an inspiration for silent flight in the aviation industry?

    Science.gov (United States)

    Bachmann, Thomas; Mühlenbruch, Georg; Wagner, Hermann

    2011-04-01

    Barn owls are specialists in prey detection using acoustic information. The flight apparatus of this bird of prey is most efficiently adapted to the hunting behavior by reducing flight noise. An understanding of the underlying mechanisms owls make use of could help minimize the noise disturbances in airport or wind power plant neighborhood. Here, we characterize wings of barn owls in terms of an airfoil as a role model for studying silent flight. This characterization includes surface and edge specialization (serrations, fringes) evolved by the owl. Furthermore, we point towards possible adaptations of either noise suppression or air flow control that might be an inspiration for the construction of modern aircraft. Three-dimensional imaging techniques such as surface digitizing, computed tomography and confocal laser scanning microscopy were used to investigate the wings and feathers in high spatial resolution. We show that wings of barn owls are huge in relation to their body mass resulting in a very low wing loading which in turn enables a slow flight and an increased maneuverability. Profiles of the wing are highly cambered and anteriorly thickened, especially at the proximal wing, leading to high lift production during flight. However, wind tunnel experiments showed that the air flow tends to separate at such wing configurations, especially at low-speed flight. Barn owls compensated this problem by evolving surface and edge modifications that stabilize the air flow. A quantitative three-dimensionally characterization of some of these structures is presented.

  8. Multifunctional reactors

    NARCIS (Netherlands)

    Westerterp, K.R.

    1992-01-01

    Multifunctional reactors are single pieces of equipment in which, besides the reaction, other functions are carried out simultaneously. The other functions can be a heat, mass or momentum transfer operation and even another reaction. Multifunctional reactors are not new, but they have received much

  9. Microsatellite markers characterized in the barn owl (Tyto alba) and of high utility in other owls (Strigiformes: AVES).

    Science.gov (United States)

    Klein, Akos; Horsburgh, Gavin J; Küpper, Clemens; Major, Agnes; Lee, Patricia L M; Hoffmann, Gyula; Mátics, Róbert; Dawson, Deborah A

    2009-11-01

    We have identified 15 polymorphic microsatellite loci for the barn owl (Tyto alba), five from testing published owl loci and 10 from testing non-owl loci, including loci known to be of high utility in passerines and shorebirds. All 15 loci were sequenced in barn owl, and new primer sets were designed for eight loci. The 15 polymorphic loci displayed two to 26 alleles in 56-58 barn owls. When tested in 10 other owl species (n = 1-6 individuals), between four and nine loci were polymorphic per species. These loci are suitable for studies of population structure and parentage in owls.

  10. On Barnes Beta Distributions and Applications to the Maximum Distribution of the 2D Gaussian Free Field

    Science.gov (United States)

    Ostrovsky, Dmitry

    2016-09-01

    A new family of Barnes beta distributions on (0, ∞) is introduced and its infinite divisibility, moment determinacy, scaling, and factorization properties are established. The Morris integral probability distribution is constructed from Barnes beta distributions of types (1, 0) and (2, 2), and its moment determinacy and involution invariance properties are established. For application, the maximum distributions of the 2D gaussian free field on the unit interval and circle with a non-random logarithmic potential are conjecturally related to the critical Selberg and Morris integral probability distributions, respectively, and expressed in terms of sums of Barnes beta distributions of types (1, 0) and (2, 2).

  11. Semi-annual monitoring report for Barnes, Kansas, for July-December 2009.

    Energy Technology Data Exchange (ETDEWEB)

    LaFreniere, L. M.; Environmental Science Division

    2010-04-27

    The Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) operated a grain storage facility at Barnes, Kansas, during most of the interval 1949-1974. Carbon tetrachloride contamination was initially detected in 1986 in the town's public water supply wells. In 2006-2007, the CCC/USDA conducted a comprehensive targeted investigation at and near its former property in Barnes to characterize this contamination. Those results were reported previously (Argonne 2008a). In November 2007, the CCC/USDA began quarterly groundwater monitoring at Barnes. The monitoring is being conducted on behalf of the CCC/USDA by Argonne National Laboratory, in accord with the recommendations made in the report for the 2006-2007 targeted investigation (Argonne 2008a). The objective is to monitor the carbon tetrachloride contamination identified in the groundwater at Barnes. The sampling is presently conducted in a network of 28 individual monitoring wells (at 19 distinct locations), 2 public water supply wells, and 1 private well (Figure 1.1). The results of the 2006-2007 targeted investigation and the subsequent monitoring events (Argonne 2008a-d, 2009a,b) demonstrated the presence of carbon tetrachloride contamination in groundwater at levels exceeding the Kansas Department of Health and Environment (KDHE) Tier 2 risk-based screening level (RBSL) of 5.0 {micro}g/L for this compound. The contaminant plume appears to extend from the former CCC/USDA property northwestward, toward the Barnes public water supply wells. Information obtained during the 2006-2007 investigation indicates that at least one other potential source might have contributed to the groundwater contaminant plume (Argonne 2008a). The former agriculture building owned by the local school district, located immediately east of well PWS3, is also a potential source of the contamination. This current report presents the results of the seventh quarterly monitoring event, conducted in September

  12. Reactor vessel

    OpenAIRE

    Makkee, M.; Kapteijn, F.; Moulijn, J.A

    1999-01-01

    A reactor vessel (1) comprises a reactor body (2) through which channels (3) are provided whose surface comprises longitudinal inwardly directed parts (4) and is provided with a catalyst (6), as well as buffer bodies (8, 12) connected to the channels (3) on both sides of the reactor body (2) and comprising connections for supplying (9, 10, 11) and discharging (13, 14, 15) via the channels (3) gases and/or liquids entering into a reaction with each other and substances formed upon this reactio...

  13. Remaining Sites Verification Package for the 141-C Large Animal Barn and Biology Laboratory (Hog Barn), Waste Site Reclassification Form 2006-027

    Energy Technology Data Exchange (ETDEWEB)

    R. A. Carlson

    2006-05-24

    The 141-C waste site is a former large animal barn and biology laboratory within the 100-F Area experimental animal farm. Strontium-90, arsenic, and multiple polycyclic aromatic hydrocarbons were detected within residual demolition debris at concentrations exceeding cleanup criteria. The site has been remediated by removing approximately 900 bank cubic meters of soil and debris within the former building footprint to the Environmental Restoration Disposal Facility. The results of verification sampling demonstrated that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also showed that residual contaminant concentrations are protective of groundwater and the Columbia River.

  14. Sex steroid hormones in barn swallow (Hirundo rustica) populations at a dioxin contaminated site in northeast Louisiana

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This study compares the gonadal sex steroid hormone levels (i.e., estradiol, total estrogen, and testosterone) in Louisiana barn swallows (Hirundo rustica) that were...

  15. NUCLEAR REACTOR

    Science.gov (United States)

    Miller, H.I.; Smith, R.C.

    1958-01-21

    This patent relates to nuclear reactors of the type which use a liquid fuel, such as a solution of uranyl sulfate in ordinary water which acts as the moderator. The reactor is comprised of a spherical vessel having a diameter of about 12 inches substantially surrounded by a reflector of beryllium oxide. Conventionnl control rods and safety rods are operated in slots in the reflector outside the vessel to control the operation of the reactor. An additional means for increasing the safety factor of the reactor by raising the ratio of delayed neutrons to prompt neutrons, is provided and consists of a soluble sulfate salt of beryllium dissolved in the liquid fuel in the proper proportion to obtain the result desired.

  16. Reactor Neutrinos

    Directory of Open Access Journals (Sweden)

    Soo-Bong Kim

    2013-01-01

    Full Text Available We review the status and the results of reactor neutrino experiments. Short-baseline experiments have provided the measurement of the reactor neutrino spectrum, and their interest has been recently revived by the discovery of the reactor antineutrino anomaly, a discrepancy between the reactor neutrino flux state of the art prediction and the measurements at baselines shorter than one kilometer. Middle and long-baseline oscillation experiments at Daya Bay, Double Chooz, and RENO provided very recently the most precise determination of the neutrino mixing angle θ13. This paper provides an overview of the upcoming experiments and of the projects under development, including the determination of the neutrino mass hierarchy and the possible use of neutrinos for society, for nonproliferation of nuclear materials, and geophysics.

  17. Chemical Reactors.

    Science.gov (United States)

    Kenney, C. N.

    1980-01-01

    Describes a course, including content, reading list, and presentation on chemical reactors at Cambridge University, England. A brief comparison of chemical engineering education between the United States and England is also given. (JN)

  18. Reactor Neutrinos

    OpenAIRE

    Lasserre, T.; Sobel, H.W.

    2005-01-01

    We review the status and the results of reactor neutrino experiments, that toe the cutting edge of neutrino research. Short baseline experiments have provided the measurement of the reactor neutrino spectrum, and are still searching for important phenomena such as the neutrino magnetic moment. They could open the door to the measurement of coherent neutrino scattering in a near future. Middle and long baseline oscillation experiments at Chooz and KamLAND have played a relevant role in neutrin...

  19. Avian pox virus infection in a common barn owl (Tyto alba in southern Brazil

    Directory of Open Access Journals (Sweden)

    Gilberto D. Vargas

    2011-07-01

    Full Text Available A young common barn owl (Tyto alba was referred to the Núcleo de Reabilitação da Fauna Silvestre (Nurfs, Federal University of Pelotas (UFPel, after been found in a barn of a brick factory in the urban area of Pelotas, Rio Grande do Sul, Brazil. The bird was apathic, weak and with crusty lesions in the featherless areas (eyes, beak, legs, and died soon after arrival at Nurfs. Necropsy and histopathological examination of the lesions were carried out. The hyperplasia and hypertrophy of the cutaneous lesions, several eosinophilic intracyto-plasmic inclusion bodies in epithelial cells (Bollinger bodies, as well as particles characteristic of poxvirus, observed by electronic microscopy, confirmed the infection by avian poxvirus, what highlights the importance of Tyto alba as carrier of the virus in the wild.

  20. Att stärka delaktigheten hos barn med autism på daghem : En litteraturstudie

    OpenAIRE

    Rikberg, Sofie

    2012-01-01

    Idag strävas det efter att barn med lindrigare former av autism så långt som möjligt skall integreras i daghem. På grund av de svårigheter som barnet med autism har löper det risk att bli utanför gemenskapen på daghemmet. Examensarbetet beskriver i form av en litteraturstudie beskriva hur de professionella kan stärka delaktigheten hos barn med autism på daghem och därmed främja möjligheterna till social inklusion. Frågeställningen är följande: Hur kan professionella forma verksamheten på dag...

  1. Multimodal signalling in the North American barn swallow: a phenotype network approach

    Science.gov (United States)

    Wilkins, Matthew R.; Shizuka, Daizaburo; Joseph, Maxwell B.; Hubbard, Joanna K.; Safran, Rebecca J.

    2015-01-01

    Complex signals, involving multiple components within and across modalities, are common in animal communication. However, decomposing complex signals into traits and their interactions remains a fundamental challenge for studies of phenotype evolution. We apply a novel phenotype network approach for studying complex signal evolution in the North American barn swallow (Hirundo rustica erythrogaster). We integrate model testing with correlation-based phenotype networks to infer the contributions of female mate choice and male–male competition to the evolution of barn swallow communication. Overall, the best predictors of mate choice were distinct from those for competition, while moderate functional overlap suggests males and females use some of the same traits to assess potential mates and rivals. We interpret model results in the context of a network of traits, and suggest this approach allows researchers a more nuanced view of trait clustering patterns that informs new hypotheses about the evolution of communication systems. PMID:26423842

  2. Multimodal signalling in the North American barn swallow: a phenotype network approach.

    Science.gov (United States)

    Wilkins, Matthew R; Shizuka, Daizaburo; Joseph, Maxwell B; Hubbard, Joanna K; Safran, Rebecca J

    2015-10-01

    Complex signals, involving multiple components within and across modalities, are common in animal communication. However, decomposing complex signals into traits and their interactions remains a fundamental challenge for studies of phenotype evolution. We apply a novel phenotype network approach for studying complex signal evolution in the North American barn swallow (Hirundo rustica erythrogaster). We integrate model testing with correlation-based phenotype networks to infer the contributions of female mate choice and male-male competition to the evolution of barn swallow communication. Overall, the best predictors of mate choice were distinct from those for competition, while moderate functional overlap suggests males and females use some of the same traits to assess potential mates and rivals. We interpret model results in the context of a network of traits, and suggest this approach allows researchers a more nuanced view of trait clustering patterns that informs new hypotheses about the evolution of communication systems.

  3. Geographic variation in sexual selection and implications for speciation in the Barn Swallow

    Institute of Scientific and Technical Information of China (English)

    Elizabeth SC Scordato; Rebecca J Safran

    2015-01-01

    Barn Swal ows (Hirundo rustica), a group of passerine birds comprised of six closely related subspecies, are well known throughout their nearly worldwide distribution, in part because of their close association with human settlements. A tractable species for both individual-based and population-level studies, Barn Swallows are a prominent model system in evolutionary, ecological, and behavioral research. Here we review work on sexual selection and population divergence in this species complex, focusing on comparative studies among populations and subspecies. We summarize variation in the targets of mate choice and in the information conveyed by sexually selected traits, and conclude that the benefits advertised by different traits may vary geographical y. Finally, we consider the role of sexual selection as a driver of population divergence in this widespread and phenotypically variable species complex.

  4. Geographic variation in sexual selection and implications for speciation in the Barn Swallow

    Institute of Scientific and Technical Information of China (English)

    Elizabeth; SC; Scordato; Rebecca; J; Safran

    2015-01-01

    Barn Swallows(Hirundo rustica), a group of passerine birds comprised of six closely related subspecies, are well known throughout their nearly worldwide distribution, in part because of their close association with human settlements.A tractable species for both individual-based and population-level studies, Barn Swallows are a prominent model system in evolutionary, ecological, and behavioral research. Here we review work on sexual selection and population divergence in this species complex, focusing on comparative studies among populations and subspecies.We summarize variation in the targets of mate choice and in the information conveyed by sexually selected traits, and conclude that the benefits advertised by different traits may vary geographically. Finally, we consider the role of sexual selection as a driver of population divergence in this widespread and phenotypically variable species complex.

  5. Mellin-Barnes representations of Feynman diagrams, linear systems of differential equations, and polynomial solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kalmykov, Mikhail Yu.; Kniehl, Bernd A. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2012-05-15

    We argue that the Mellin-Barnes representations of Feynman diagrams can be used for obtaining linear systems of homogeneous differential equations for the original Feynman diagrams with arbitrary powers of propagators without recourse to the integration-by-parts technique. These systems of differential equation can be used (i) for the differential reductions to sets of basic functions and (ii) for counting the numbers of master-integrals.

  6. Female plumage spottiness signals parasite resistance in the barn owl (Tyto alba)

    OpenAIRE

    Roulin, A.; Riols, C; Dijkstra, C; Ducrest, A. L.

    2001-01-01

    The hypothesis that extravagant ornaments signal parasite resistance has received support in several species for ornamented males but more rarely for ornamented females. However, recent theories have proposed that females should often be under sexual selection, and therefore females may signal the heritable capacity to resist parasites. We investigated this hypothesis in the socially monogamous barn owl, Tyto alba, in which females exhibit on average more and larger black spots on the plumage...

  7. Compounding effects on nest-site dispersal of Barn Owls Tyto alba

    DEFF Research Database (Denmark)

    Huffeldt, Nicholas Per; Aggerholm, Iben Næs; Brandtberg, Nathia Hass

    2012-01-01

    Capsule Recovery distances of Barn Owls ringed as pulli are conditional on ringing date but not on population density. Aims To test whether ring recovery distances (proxy for natal dispersal distances) were conditional on population density and reproductive timing. Methods We used ringing data...... from 0 to 100 days after ringing, being stable thereafter, and was also impacted by brood size. Owls ringed very early or late in the breeding season were more likely to be recovered

  8. Performance and Health of Group-Housed Calves Kept in Igloo Calf Hutches and Calf Barn

    Directory of Open Access Journals (Sweden)

    Jerzy Wójcik*, Renata Pilarczyk, Anna Bilska, Ottfried Weiher1 and Peter Sanftleben1

    2013-04-01

    Full Text Available Group-reared calves are usually housed in common buildings, such as calf barns of all sorts; however, there are concerns about this practice due to problems such as an increased incidence of diseases and poor performance of the calves. Group calf rearing using igloo hutches may be a solution combining the benefits of individual and group housing systems. The aim of this study was to evaluate group-reared calves housed in Igloo-type hutches compared with those housed in common calf barns. The experiment was carried out on a large private dairy farm located in Vorpommern, Germany. A total of 90 Deutsche-Holstein bull calves were assigned to 2 treatment groups: the calf-barn group, with calves grouped in pens in a building, and the Igloo-hutch group, with calves housed in outdoor enclosures with an access to group igloo-style hutches. Calves entering the 84-day experiment were at an average age of about three weeks, with the mean initial body weight of about 50 kg. The calves housed in the group Igloo hutches attained higher daily weight gains compared to those housed in the calf barn (973 vs 721 g/day, consumed more solid feeds (concentrate, corn grain and maize silage: (1.79 vs 1.59 kg/day, and less milk replacer (5.51 vs 6.19 kg/day, had also a lower incidence of respiratory diseases (1.24 vs 3.57% with a shorter persistence of the illness.

  9. The double Mellin-Barnes type integrals and their applications to convolution theory

    CERN Document Server

    Hai, Nguyen Thanh

    1992-01-01

    This book presents new results in the theory of the double Mellin-Barnes integrals popularly known as the general H-function of two variables.A general integral convolution is constructed by the authors and it contains Laplace convolution as a particular case and possesses a factorization property for one-dimensional H-transform. Many examples of convolutions for classical integral transforms are obtained and they can be applied for the evaluation of series and integrals.

  10. Archeological Testing at 32BA414, Lake Ashtabula, Barnes County, North Dakota.

    Science.gov (United States)

    1984-02-01

    and Block 1967:44). Thick glacial drift (as deep as 95 m) blankets Barnes County (Kelly and Block 1967:17). Glacial till is dense east of 32BA414 in the...many roots) North Wail Profile Sa1ndy LearN 10YR 312 SandY Loarn lOf 311 (fewrn oot*) Sandy Sit Lesrn lOY" 312 Toat Unit 6 Sand 16O1M 313 West Wall

  11. Evolutionary conservation of Kv3.1 in the barn owl Tyto alba.

    Science.gov (United States)

    Kullmann, Lars; Schlüter, Tina; Wagner, Hermann; Nothwang, Hans Gerd

    2013-01-01

    For prey capture in the dark, the barn owl Tyto alba has evolved into an auditory specialist with an exquisite capability of sound localization. Adaptations include asymmetrical ears, enlarged auditory processing centers, the utilization of minute interaural time differences, and phase locking along the entire hearing range up to 10 kHz. Adaptations on the molecular level have not yet been investigated. Here, we tested the hypothesis that divergence in the amino acid sequence of the voltage-gated K(+) channel Kv3.1 contributes to the accuracy and high firing rates of auditory neurons in the barn owl. We therefore cloned both splice variants of Kcnc1, the gene encoding Kv3.1. Both splice variants, Kcnc1a and Kcnc1b, encode amino acids identical to those of the chicken, an auditory generalist. Expression analyses confirmed neural-restricted expression of the channel. In summary, our data reveal strong evolutionary conservation of Kcnc1 in the barn owl and point to other genes involved in auditory specializations of this animal. The data also demonstrate the feasibility to address neuroethological questions in organisms with no reference genome by molecular approaches. This will open new avenues for neuroethologists working in these organisms.

  12. Practical Encoders and Decoders for Euclidean Codes from Barnes-Wall Lattices

    CERN Document Server

    Harshan, J; Belfiore, Jean-Claude

    2012-01-01

    It is well known that dense lattice packings can be obtained via Construction $A$ from \\emph{binary} linear codes. In this paper, we propose an extension of Construction $A$ called Construction $A^\\prime$ to obtain Barnes-Wall lattices from linear codes over finite rings. To obtain the Barnes-Wall lattice $BW_{2^{m}}$ in $\\mathbb{C}^{2^{m}}$ for any $m \\geq 1$, we identify a linear code $\\mathcal{C}_{2^m}$ over a polynomial ring and then embed the linear code to a lattice constellation $\\mathcal{L}_{2^{m}}$ such that $BW_{2^{m}}$ can be obtained as $BW_{2^{m}} = (1+i)^{m}\\mathbb{Z}[i]^{2^{m}} \\oplus \\mathcal{L}_{2^{m}}$ where $i = \\sqrt{-1}$. We also show that $\\mathcal{L}_{2^{m}}$ has the cubic shaping property when $m$ is even. We highlight that Construction $A^\\prime$ provides a convenient technique for bit-labelling Barnes-Wall lattice constellations. We also employ the lattice constellation $\\mathcal{L}_{2^{m}}$ as a coded modulation scheme for AWGN channels. To encode the code, we use Construction $A^{\\...

  13. Barn og fysisk aktivitet i barnehagen: Hvordan kan aktivitetsnivået dokumenteres?

    Directory of Open Access Journals (Sweden)

    Anne Stokke

    2014-12-01

    Full Text Available Abstract: We monitored the physical activity levels of 42 children during a regular day in kindergarten, using various instruments. This study will provide knowledge about children’s activity levels in kindergarten. It also discusses whether children’s activity levels can be adequately evaluated by the teachers or if there is a need for technical measurements. In addition, we compared the different instruments used to evaluate the children. The employees in the kindergarten were asked to answer a questionnaire about the children’s physical activity level during the day, and a student or a researcher observed and registered one child each. During the same day, activity levels were monitored using actigraphy (AC; Actigraf GT3X and continuous heart rate monitoring (HR; Team2 Polar ® in 14 children (six boys and eight girls, 38 and 47 months old, respectively. The researcher-observations defined the observed children as “moderately active”, and AC-data showed that all children had more than 60 minutes of moderate - or high - intensity activity. According to our comparisons, the use of HR to assess the activity in kindergartens is not recommended. On average, the questionnaires reported similar physical activity levels for the same child, although the evaluations varied between employees. When comparing one active and one inactive child, the different methods showed similar results. We conclude that professionals can see a child’s physical activity level when asked to reflect upon it.Sammendrag: Vi målte det fysiske aktivitetsnivået til 42 barn i løpet av en vanlig dag i barnehagen ved hjelp av ulike instrumenter. Denne studien vil gi kunnskap om barns fysiske aktivitet i barnehagen, og om barnas aktivitetsnivå kan bli tilstrekkelig evaluert av lærerne eller om det er behov for tekniske målinger. Videre har vi sammenlignet de ulike instrumentene brukt i observasjonen. De ansatte i barnehagen ble bedt om å svare på et sp

  14. Sonochemical Reactors.

    Science.gov (United States)

    Gogate, Parag R; Patil, Pankaj N

    2016-10-01

    Sonochemical reactors are based on the generation of cavitational events using ultrasound and offer immense potential for the intensification of physical and chemical processing applications. The present work presents a critical analysis of the underlying mechanisms for intensification, available reactor configurations and overview of the different applications exploited successfully, though mostly at laboratory scales. Guidelines have also been presented for optimum selection of the important operating parameters (frequency and intensity of irradiation, temperature and liquid physicochemical properties) as well as the geometric parameters (type of reactor configuration and the number/position of the transducers) so as to maximize the process intensification benefits. The key areas for future work so as to transform the successful technique at laboratory/pilot scale into commercial technology have also been discussed. Overall, it has been established that there is immense potential for sonochemical reactors for process intensification leading to greener processing and economic benefits. Combined efforts from a wide range of disciplines such as material science, physics, chemistry and chemical engineers are required to harness the benefits at commercial scale operation.

  15. Effect of scraping frequency in a freestall barn on volatile nitrogen loss from dairy manure.

    Science.gov (United States)

    Moreira, V R; Satter, L D

    2006-07-01

    The objective of this investigation was to evaluate the effect of scraping frequency (2x vs. 6x daily) on N volatilization from manure on the floor of a dairy free-stall barn. Three trials (crossover design) were conducted in the summers of 2001 and 2002, and in the winter of 2003. Nitrogen volatilization was estimated from the change in the N:P ratio in excreta at the time of excretion to the time when manure was scraped from the barn. Total N loss was considered a maximum estimate of NH3-N loss, because small amounts of nonammonia N may be volatilized. Nitrogen was determined after manure subsamples were lyophilized; P content was measured by direct current emission spectroscopy of ashed subsamples of manure. Lactating dairy cows were fed high-protein (18.5 to 19.3% crude protein), alfalfa-based diets. Average milk yield was 31.9 (SD = 7.4) kg/d. Scraping frequency had no effect on N loss in summer 2001. An average of 41% of excreted N, or 238 +/- 19.0 g of N/d per cow, was volatilized. For the trial in summer 2002, nitrogen volatilization was reduced from 50% of the excreted N with 2x to 46.7% with 6x, equivalent to 265 and 248 g of N lost/d per cow, respectively. Scraping had no effect on N volatilization during the winter trial. An average of 17.7% of excreted N was volatilized during the winter, equivalent to 109 +/- 11.0 g of N lost/d per cow. Scraping frequency of manure had little or no effect on N loss from manure in a freestall barn. Nitrogen loss during the winter was less than half of the loss during the summer.

  16. The Binaural Interaction Component in Barn Owl (Tyto alba) Presents few Differences to Mammalian Data.

    Science.gov (United States)

    Palanca-Castan, Nicolas; Laumen, Geneviève; Reed, Darrin; Köppl, Christine

    2016-12-01

    The auditory brainstem response (ABR) is an evoked potential that reflects the responses to sound by brainstem neural centers. The binaural interaction component (BIC) is obtained by subtracting the sum of the monaural ABR responses from the binaural response. Its latency and amplitude change in response to variations in binaural cues. The BIC is thus thought to reflect the activity of binaural nuclei and is used to non-invasively test binaural processing. However, any conclusions are limited by a lack of knowledge of the relevant processes at the level of individual neurons. The aim of this study was to characterize the ABR and BIC in the barn owl, an animal where the ITD-processing neural circuits are known in great detail. We recorded ABR responses to chirps and to 1 and 4 kHz tones from anesthetized barn owls. General characteristics of the barn owl ABR were similar to those observed in other bird species. The most prominent peak of the BIC was associated with nucleus laminaris and is thus likely to reflect the known processes of ITD computation in this nucleus. However, the properties of the BIC were very similar to previously published mammalian data and did not reveal any specific diagnostic features. For example, the polarity of the BIC was negative, which indicates a smaller response to binaural stimulation than predicted by the sum of monaural responses. This is contrary to previous predictions for an excitatory-excitatory system such as nucleus laminaris. Similarly, the change in BIC latency with varying ITD was not distinguishable from mammalian data. Contrary to previous predictions, this behavior appears unrelated to the known underlying neural delay-line circuitry. In conclusion, the generation of the BIC is currently inadequately understood and common assumptions about the BIC need to be reconsidered when interpreting such measurements.

  17. Problemer med å måle eksponering for passiv røyking blant barn

    Directory of Open Access Journals (Sweden)

    Per Nafstad m.fl.

    2009-10-01

    Full Text Available  SAMMENDRAGVanligvis måles eksponering for passiv røyking blant barn ved spørreskjemaopplysninger omforeldres røykevaner. Etter hvert som det blir mer oppmerksomhet om helseeffekter av passivrøyking, vil det kunne påvirke hvordan foreldre røyker og dermed også barns eksponering. Medhenvisning til innsamlede data om røykeeksponering i en kohort av Oslo-barn og fra en studie avbarn ved to helsestasjoner, diskuteres noen av de metodeproblemene en står overfor når en skal måleeksponering for passiv røyking i epidemiologiske studier. I disse studiene er barns eksponering forpassiv røyking målt ved spørreskjemaopplysninger og ved måling av hårnikotin og kotinin i urin.Det konkluderes med at det er usikkerhet om nøyaktigheten av eksisterende metoder for måling avpassiv røyking. Dette og manglende kunnskap om faktisk eksponeringsnivå kan føre til feilaktigestimering av helseeffekter av passiv røyking i en barnebefolkning.Nafstad P, Botten G, Magnus P. Problems in measuring environmental tobacco smoke exposurein children. Nor J Epidemiol 1995; 5 (2: 141-144.ENGLISH SUMMARYUsually environmental tobacco smoke exposure among children is measuered by questionnaires,recording parental smoking. As the adverse health effects of environmental tobacco smoke exposureare getting more known among the public, this is likely to influence the parents' way of smoking andby that their children's actual exposure. With references to findings in a cohort study of Oslochildren and a study of children attending two of Oslo’s health centers, some methodologicalproblems when measuring environmental tobacco smoke exposure in epidemiological studies arediscussed. The exposure in these studies is measured in questionnaires to the parents and aschildren's hair nicotine concentration and urine cotinine concentration. Furthermore, the paperdiscusses how the uncertainty in actual levels of exposure may lead to false estimates for the totalhealth impact of

  18. AMBRE - a mathematica package for the construction of Mellin-Barnes representations for Feynman integrals

    Energy Technology Data Exchange (ETDEWEB)

    Gluza, J.; Kajda, K. [Silesia Univ, Katowice (Poland). Dept. of Field Theory and Particle Physics, Inst. of Phsyics; Riemann, T. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2007-05-15

    The Mathematica toolkit AMBRE derives Mellin-Barnes (MB) representations for Feynman integrals in d=4-2{epsilon} dimensions. It may be applied for tadpoles as well as for multi-leg multi-loop scalar and tensor integrals. AMBRE uses a loop-by-loop approach and aims at lowest dimensions of the final MB representations. The present version of AMBRE works fine for planar Feynman diagrams. The output may be further processed by the package MB for the determination of its singularity structure in {epsilon}. The AMBRE package contains various sample applications for Feynman integrals with up to six external particles and up to four loops. (orig.)

  19. Mammal prey of the Barn Owl (Tyto alba) in Parque Luro Reserve, La Pampa, Argentina

    OpenAIRE

    1994-01-01

    Abstract The diet of the barn owl was studied through the analysis of pellets obtained in various sites within the Parque Luro reserve, located in an area of xerophyte Caldén forests. The study of 1241 prey items revealed a high dominance of the cricetid rodents Calomys sp., Akodon molinae and Eligmodontia typus, followed by other 8 species of rodents, one species of marsupial and undetermined birds a...

  20. Kortisonskepsis : En studie om holdninger til kortisonkrem blant foreldre av barn med atopisk eksem

    OpenAIRE

    Gustavsen, Hanne Engstrøm

    2010-01-01

    Bakgrunn: Kortisonkremer er en viktig del av behandlingen mot atopisk eksem. Mange foreldre er skeptiske til bruken av kortisonkremer, fordi de har lest eller hørt om bivirkninger. Pasienters og pårørendes holdninger til bruk av kortisonkrem kan påvirke gjennomføringen av behandlingen. Formål: Vi ønsket å undersøke holdninger til bruk av kortisonkrem blant foreldre og pårørende av barn med atopisk eksem. Vi ville også undersøke om det er en sammenheng mellom kunnskapsnivå om kortisonkreme...

  1. Infektioner hos barn i förskola- gör utevistelse skillnad?

    DEFF Research Database (Denmark)

    Blennow, Margareta; Söderström, Margareta

    2009-01-01

    Under åren i förskolan har barn många infektioner, framförallt luftvägsinfektioner. Det finns indikationer på att allt fler föräldrar efterfrågar förskolor där barnen är utomhus hela dagen. Gör det barnen friskare? Den vetenskapliga litteraturen på området är sparsam. Resultaten är inte entydiga ...

  2. ”Vissa barn älskar faktiskt sånna dära TV-reklamer” : - En övergripande studie om hur barn upplever och tolkar TV-reklam -

    OpenAIRE

    Norberg, Lotta

    2007-01-01

    ABSTRACT Titel: “Some kids really love those commercials” -A study of how children experience and construe commercials. (Vissa barn älskar faktiskt sånna dära TV-reklamer” – En övergripande studie om hur barn upplever och tolkar tv-reklam.) Number of pages: 40 Author: Lotta Norberg Tutor: Amelie Hössjer Course: Media and Communication Studies C Period: Autumn term 2007 University: Division of Media and Communication, Department of Information Science, Uppsala University Purpose/Aim: The aim o...

  3. Optimization of Apparatus Design and Behavioral Measures for the Assessment of Visuo-Spatial Learning and Memory of Mice on the Barnes Maze

    Science.gov (United States)

    O'Leary, Timothy P.; Brown, Richard E.

    2013-01-01

    We have previously shown that apparatus design can affect visual-spatial cue use and memory performance of mice on the Barnes maze. The present experiment extends these findings by determining the optimal behavioral measures and test procedure for analyzing visuo-spatial learning and memory in three different Barnes maze designs. Male and female…

  4. An additional field method to sex adult Barn Swallows during the non-breeding season in Zambia: white spot length in the outer tail feather

    NARCIS (Netherlands)

    Duijns, S.; Dijk, van J.G.B.; Kraus, R.H.S.; Kerlen-Matema, A.C.; Brink, van den B.; Hooft, van W.F.

    2011-01-01

    Adult Barn Swallows Hirundo rustica exhibit strong sexual size dimorphism in the length of the outermost tail feathers, which are longer in males compared with females. This trait is traditionally used to sex adult Barn Swallows in the field. However, due to the wear and breakage of the tips of the

  5. Visual pop-out in barn owls: Human-like behavior in the avian brain.

    Science.gov (United States)

    Orlowski, Julius; Beissel, Christian; Rohn, Friederike; Adato, Yair; Wagner, Hermann; Ben-Shahar, Ohad

    2015-01-01

    Visual pop-out is a phenomenon by which the latency to detect a target in a scene is independent of the number of other elements, the distractors. Pop-out is an effective visual-search guidance that occurs typically when the target is distinct in one feature from the distractors, thus facilitating fast detection of predators or prey. However, apart from studies on primates, pop-out has been examined in few species and demonstrated thus far in rats, archer fish, and pigeons only. To fill this gap, here we study pop-out in barn owls. These birds are a unique model system for such exploration because their lack of eye movements dictates visual behavior dominated by head movements. Head saccades and interspersed fixation periods can therefore be tracked and analyzed with a head-mounted wireless microcamera--the OwlCam. Using this methodology we confronted two owls with scenes containing search arrays of one target among varying numbers (15-63) of similar looking distractors. We tested targets distinct either by orientation (Experiment 1) or luminance contrast (Experiment 2). Search time and the number of saccades until the target was fixated remained largely independent of the number of distractors in both experiments. This suggests that barn owls can exhibit pop-out during visual search, thus expanding the group of species and brain structures that can cope with this fundamental visual behavior. The utility of our automatic analysis method is further discussed for other species and scientific questions.

  6. The maintenance of phenotypic divergence through sexual selection: An experimental study in barn swallows Hirundo rustica.

    Science.gov (United States)

    Safran, Rebecca J; Vortman, Yoni; Jenkins, Brittany R; Hubbard, Joanna K; Wilkins, Matthew R; Bradley, Rachel J; Lotem, Arnon

    2016-09-01

    Previous studies have shown that sexual signals can rapidly diverge among closely related species. However, we lack experimental studies to demonstrate that differences in trait-associated reproductive performance maintain sexual trait differences between closely related populations, in support for a role of sexual selection in speciation. Populations of Northern Hemisphere distributed barn swallows Hirundo rustica are closely related, yet differ in two plumage-based traits: ventral color and length of the outermost tail feathers (streamers). Here we provide experimental evidence that manipulations of these traits result in different reproductive consequences in two subspecies of barn swallow: (H. r. erythrogaster in North America and H. r. transitiva in the East Mediterranean). Experimental results in Colorado, USA, demonstrate that males with (1) darkened ventral coloration and (2) shortened streamers gained paternity between two successive reproductive bouts. In contrast, exaggeration of both traits improved reproductive performance within H. r. transitiva in Israel: males with a combination treatment of darkened ventral coloration and elongated streamers gained paternity between two successive reproductive bouts. Collectively, these experimental results fill an important gap in our understanding for how divergent sexual selection maintains phenotype differentiation in closely related populations, an important aspect of the speciation process.

  7. An automatic system for the detection of dairy cows lying behaviour in free-stall barns

    Directory of Open Access Journals (Sweden)

    Simona M.C. Porto

    2013-09-01

    Full Text Available In this paper, a method for the automatic detection of dairy cow lying behaviour in free-stall barns is proposed. A computer visionbased system (CVBS composed of a video-recording system and a cow lying behaviour detector based on the Viola Jones algorithm was developed. The CVBS performance was tested in a head-to-head free stall barn. Two classifiers were implemented in the software component of the CVBS to obtain the cow lying behaviour detector. The CVBS was validated by comparing its detection results with those generated from visual recognition. This comparison allowed the following accuracy indices to be calculated: the branching factor (BF, the miss factor (MF, the sensitivity, and the quality percentage (QP. The MF value of approximately 0.09 showed that the CVBS missed one cow every 11 well detected cows. Conversely, the BF value of approximately 0.08 indicated that one false positive was detected every 13 well detected cows. The high value of approximately 0.92 obtained for the sensitivity index and that obtained for QP of about 0.85 revealed the ability of the proposed system to detect cows lying in the stalls.

  8. Non-Perturbative Asymptotic Improvement of Perturbation Theory and Mellin-Barnes Representation

    Directory of Open Access Journals (Sweden)

    Samuel Friot

    2010-10-01

    Full Text Available Using a method mixing Mellin-Barnes representation and Borel resummation we show how to obtain hyperasymptotic expansions from the (divergent formal power series which follow from the perturbative evaluation of arbitrary ''N-point'' functions for the simple case of zero-dimensional φ4 field theory. This hyperasymptotic improvement appears from an iterative procedure, based on inverse factorial expansions, and gives birth to interwoven non-perturbative partial sums whose coefficients are related to the perturbative ones by an interesting resurgence phenomenon. It is a non-perturbative improvement in the sense that, for some optimal truncations of the partial sums, the remainder at a given hyperasymptotic level is exponentially suppressed compared to the remainder at the preceding hyperasymptotic level. The Mellin-Barnes representation allows our results to be automatically valid for a wide range of the phase of the complex coupling constant, including Stokes lines. A numerical analysis is performed to emphasize the improved accuracy that this method allows to reach compared to the usual perturbative approach, and the importance of hyperasymptotic optimal truncation schemes.

  9. The Jellyfish hunter--Jack Barnes: a pioneer medical toxinologist in Australia.

    Science.gov (United States)

    Pearn, John; Fenner, Peter

    2006-12-01

    Dr Jack Handyside Barnes (1922-1985) was one of the small and elite group of Pacific marine toxinologists whose work was characterised by an uncompromising rugged persona, a focussed resolve to solve challenging problems of human clinical envenomation, and who conducted curiosity-driven research under conditions of scientific isolation. He was a pioneering advocate for the preservation of marine heritage, particularly that of the Great Barrier Reef. A former military commando who later became a general medical practitioner with extensive surgical and obstetric skills, in 1947 he was appointed the Medical Superintendent of Thursday Island in the Torres Strait. Later (from January 1953), he worked indefatigably as a general medical practitioner in Cairns, in tropical North Australia. For four decades (1945-1985), Jack Barnes undertook detailed laboratory, clinical and field research into invertebrate envenomation, particularly medusan toxinology. In 1960 he discovered the species responsible for the Irukandji syndrome, a small carybdeid named Carukia barnesi in his honour. He invented the research technique for the extraction of venom from the world's most venomous creature, the Pacific box Jellyfish, Chironex fleckeri. By 1960, he had published taxonomic details of nematocyst structure and clinical envenomation details consequent upon stings by Physalia, Cyanea, Chironex, Chiropsalmus and Carukia. This paper is a précis of the chronology of his life, contributions and influence.

  10. Fitness loss and germline mutations in barn swallows breeding in Chernobyl

    Energy Technology Data Exchange (ETDEWEB)

    Ellegren, Hans; Lindgren, Gabriella; Primmer, C.R. [Swedish Univ. of Agricultural Sciences, Animal Breeding and Genetics Dept., Uppsala (Sweden); Moeller, A.P. [Universite Pierre et Marie Curie. Lab. d`Ecologie, Paris, 75 (France)

    1997-10-09

    The severe nuclear accident at Chernobyl in 1986 resulted in the worst reported accidental exposure of radioactive material to free-living organisms. Short-term effects on human populations inhabiting polluted areas include increased incidence of thyroid cancer, infant leukaemia, and congenital malformations in newborns. Two recent studies have reported, although with some controversy, that germline mutation rates were increased in humans and voles living close to Chernobyl, but little is known about the viability of the organisms affected. Here we report an increased frequency of partial albinism, a morphological aberration associated with a loss of fitness, among barn swallows, Hirundo rustica, breeding close to Chernobyl. Heretability estimates indicate that mutations causing albinism were at least partly of germline origin. Furthermore, evidence for an increased germline mutation rate was obtained from segregation analysis at two hypervariable microsatellite loci, indicating that mutation events in barn swallows from Chernobyl were two- to tenfold higher than in birds from control areas in Ukraine and Italy. (author).

  11. Testosterone, plumage colouration and extra-pair paternity in male North-American barn swallows.

    Directory of Open Access Journals (Sweden)

    Cas Eikenaar

    Full Text Available In most monogamous bird species, circulating testosterone concentration in males is elevated around the social female's fertile period. Variation in elevated testosterone concentrations among males may have a considerable impact on fitness. For example, testosterone implants enhance behaviours important for social and extra-pair mate choice. However, little is known about the relationship between natural male testosterone concentration and sexual selection. To investigate this relationship we measured testosterone concentration and sexual signals (ventral plumage colour and tail length, and determined within and extra-pair fertilization success in male North American barn swallows (Hirundo rustica erythrogaster. Dark rusty coloured males had higher testosterone concentrations than drab males. Extra-pair paternity was common (42% and 31% of young in 2009 and 2010, respectively, but neither within- nor extra-pair fertilization success was related to male testosterone concentration. Dark rusty males were less often cuckolded, but did not have higher extra-pair or total fertilization success than drab males. Tail length did not affect within- or extra-pair fertilization success. Our findings suggest that, in North American barn swallows, male testosterone concentration does not play a significant direct role in female mate choice and sexual selection. Possibly plumage colour co-varies with a male behavioural trait, such as aggressiveness, that reduces the chance of cuckoldry. This could also explain why dark males have higher testosterone concentrations than drab males.

  12. Better-surviving barn swallow mothers produce more and better-surviving sons.

    Science.gov (United States)

    Romano, Andrea; Costanzo, Alessandra; Caprioli, Manuela; Parolini, Marco; Ambrosini, Roberto; Rubolini, Diego; Saino, Nicola

    2016-05-01

    Sex allocation theory predicts that parents are selected to bias their progeny sex ratio (SR) toward the sex that will benefit the most from parental quality. Because parental quality may differentially affect survival of sons and daughters, a pivotal test of the adaptive value of SR adjustment is whether parents overproduce offspring of the sex that accrues larger fitness advantages from high parental quality. However, this crucial test of the long-term fitness consequences of sex allocation decisions has seldom been performed. In this study of the barn swallow (Hirundo rustica), we showed a positive correlation between the proportion of sons and maternal annual survival. We then experimentally demonstrated that this association did not depend on the differential costs of rearing offspring of either sex. Finally, we showed that maternal lifespan positively predicted lifespan of sons but not of daughters. Because in barn swallows lifespan is a strong determinant of lifetime reproductive success, the results suggest that mothers overproduce offspring of the sex that benefits the most from maternal quality. Hence, irrespective of mechanisms causing the SR bias and mother-son covariation in lifespan, we provide strong evidence that sex allocation decisions of mothers can highly impact on their lifetime fitness.

  13. Food Barn for The Village Community To Strengthen Community Empowerment Program

    Directory of Open Access Journals (Sweden)

    Maulidyah Indira Hasmarini

    2016-12-01

    Full Text Available This study aimed to assess the achievement level of community empowerment in realizing food security. The result was expected to reveal a model of community empowerment, particularly farmer community institution as an attempt to attain food security. Survey was employed as the research method that involved the farmers (farmer groups as the members of Food Barn for the Village Community (Lumbung Pangan Masyarakat Desa/LPMD. Technique of rapid rural appraisal was selected in the form of quantitative and qualitative analysis. Preliminary survey in study area was carried out to obtain the characteristic and status of food security; and to mapping the potential and role of Lumbung Pangan Masyarakat Desa in the process of community empowerment. Subsequently, study and analysis was done based on the survey. The results demonstrated the active role of stakeholders (A-B-G-C was significant in supporting the farmer institution (food barn. The economic and social aspects were also evidenced to have important role in enhancing the farmer community empowerment. This model is called social engine for rural community and local institution, particularly to attain the regional food security.

  14. Laboratory-scale investigation of UV treatment of ammonia for livestock and poultry barn exhaust applications.

    Science.gov (United States)

    Rockafellow, Erin M; Koziel, Jacek A; Jenks, William S

    2012-01-01

    The feasibility of using deep ultraviolet (UV) treatment for abatement of ammonia (NH(3)) in livestock and poultry barn exhaust air was examined in a series of laboratory-scale experiments. These experiments simulated moving exhaust air through an irradiation chamber with variables of UV wavelength and dose, NH(3) concentrations, humidity, and presence of hydrogen sulfide (H(2)S). Ammonia, initially at relevant barn exhaust concentrations in air, was substantially or completely reduced by irradiation with 185 nm light. Reactions were monitored using chemiluminescence detection, gas chromatography with mass spectrometry detection, and Fourier transform infrared spectrometry, of which the latter was found to be the most informative and flexible. Detected nitrogen-containing products included N(2)O, NH(4)NO(3), and HNO(3). It was presumed that atomic oxygen is the primary photochemical product that begins the oxidative cascade. The data show that removal of NH(3) is plausible, but they highlight concerns over pollution swapping due to formation of ozone and N(2)O.

  15. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T. (Inventor); Sahimi, Muhammad (Inventor); Fayyaz-Najafi, Babak (Inventor); Harale, Aadesh (Inventor); Park, Byoung-Gi (Inventor); Liu, Paul K. T. (Inventor)

    2011-01-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  16. D and DR Reactors

    Data.gov (United States)

    Federal Laboratory Consortium — The world's second full-scale nuclear reactor was the D Reactor at Hanford which was built in the early 1940's and went operational in December of 1944.D Reactor ran...

  17. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T.; Sahimi, Muhammad; Fayyaz-Najafi, Babak; Harale, Aadesh; Park, Byoung-Gi; Liu, Paul K. T.

    2011-03-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  18. The impact of uropygial gland secretions on mechanically induced wearing of barn owl and pigeon body feathers

    Science.gov (United States)

    Ott, Benjamin; Müsse, Annika; Wagner, Hermann

    2016-04-01

    Bird feathers are remarkable structures light but yet durable providing insulation and the ability of flight. Owls are highly specialized birds of prey, widely known for their ability to y silently which is enabled by (micro-) structural specializations of the feathers. The barn owl replaces feathers less frequently in comparison to other same sized birds like pigeons, indicating a much better resistance against material fatigue of these delicate microstructures. We used axisymmetric drop shape analysis (ADSA) of water drop contact angles as a non-destructive method of characterizing wearing processes in feathers. We hypothesized that feathers become more wettable when worn. We also investigated the impact of ethanol treatment in order to remove fatty residues of the uropygial gland secretions, barn owls and pigeons use for preening, on ageing processes. Ethanol treatment resulted in a slight, but significant increase of water repellency in barn owl but not in pigeon flight feathers. Our preliminary data also suggest that the uropygial gland secretions decelerate the wearing process of the feather keratin. We observed this effect in both species, however, it was more distinct for barn owl uropygial gland secretions. The results of this study, obtained by contact angle measurements used as a non-destructive evaluation method of material fatigue, yield insights into the material fatigue of feathers and the decelerating effect of uropygial gland secretions on wear on the other hand.

  19. Reverse correlation analysis of auditory-nerve fiber responses to broadband noise in a bird, the barn owl.

    Science.gov (United States)

    Fontaine, Bertrand; Köppl, Christine; Peña, Jose L

    2015-02-01

    While the barn owl has been extensively used as a model for sound localization and temporal coding, less is known about the mechanisms at its sensory organ, the basilar papilla (homologous to the mammalian cochlea). In this paper, we characterize, for the first time in the avian system, the auditory nerve fiber responses to broadband noise using reverse correlation. We use the derived impulse responses to study the processing of sounds in the cochlea of the barn owl. We characterize the frequency tuning, phase, instantaneous frequency, and relationship to input level of impulse responses. We show that, even features as complex as the phase dependence on input level, can still be consistent with simple linear filtering. Where possible, we compare our results with mammalian data. We identify salient differences between the barn owl and mammals, e.g., a much smaller frequency glide slope and a bimodal impulse response for the barn owl, and discuss what they might indicate about cochlear mechanics. While important for research on the avian auditory system, the results from this paper also allow us to examine hypotheses put forward for the mammalian cochlea.

  20. AMBRE—a Mathematica package for the construction of Mellin Barnes representations for Feynman integrals

    Science.gov (United States)

    Gluza, J.; Kajda, K.; Riemann, T.

    2007-12-01

    The Mathematica toolkit AMBRE derives Mellin-Barnes (MB) representations for Feynman integrals in d=4-2ɛ dimensions. It may be applied for tadpoles as well as for multi-leg multi-loop scalar and tensor integrals. The package uses a loop-by-loop approach and aims at lowest dimensions of the final MB representations. The present version works fine for planar Feynman diagrams. The output may be further processed by the package MB for the determination of its singularity structure in ɛ. The AMBRE package contains various sample applications for Feynman integrals with up to six external particles and up to four loops. Program summaryProgram title:AMBRE Catalogue identifier:ADZR_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADZR_v1_0.html Program obtainable from:CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions:standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.:21 387 No. of bytes in distributed program, including test data, etc.:100 004 Distribution format:tar.gz Programming language:MATHEMATICA v.5.0 and later versions Computer:all Operating system:all RAM:sufficient for a typical installation of MATHEMATICA Classification:5; 11.1 External routines:The examples in the package use: MB.m [M. Czakon, Comput. Phys. Commun. 175 (2006) 559 (CPC Cat. Id. ADYG)], for expansions in ɛ; CUBA [T. Hahn, Comput. Phys. Commun. 168 (2005) 78 (CPC Cat. Id. ADVH)], for numerical evaluation of multidimensional integrals; CERNlib [CERN Program Library, http://cernlib.web.cern.ch/cernlib/], for the implementation of Γ and Ψ functions in Fortran. Nature of problem:Derivation of a representation for a Feynman diagram with L loops and N internal lines in d dimensions by Mellin-Barnes integrals; the subsequent evaluation, after an analytical continuation in ɛ=(4-d)/2, has to be done with other packages. Solution method:Introduction of N Feynman parameters x

  1. El museo y la enciclopedia: Lecturas cruzadas de Borges y Barnes

    Directory of Open Access Journals (Sweden)

    Leticia Moneta

    2014-01-01

    Full Text Available Taking in consideration the intertextual and biographical influence of the works of Jorge Luis Borges on the works of Julian Barnes, this article seeks to focus on certain borgian traces that speak of the status of literature in the present time. Starting with the image of the “museum and the encyclopedia” we can read Borges from a barnesian point of view and viceversa, while insisting in the relativity of any kind of order and classification. We shall start with the essential distrust that both authors show towards language. No one can deny that in the literary and critic landscape of our time Borges is a difficult character to overcome or ignore which we will use as a reading and writing mechanism.

  2. Avian wing geometry and kinematics of a free-flying barn owl in flapping flight

    Science.gov (United States)

    Wolf, Thomas; Konrath, Robert

    2015-02-01

    This paper presents results of high-resolution three-dimensional wing shape measurements performed on free-flying barn owls in flapping flight. The applied measurement technique is introduced together with a moving camera set-up, allowing for an investigation of the free flapping flight of birds with high spatial and temporal resolution. Based on the three-dimensional surface data, a methodology for parameterizing the wing profile along with wing kinematics during flapping flight has been developed. This allowed a description of the spanwise varying kinematics and aerodynamic parameters (e.g. effective angles of attack, camber, thickness) of the wing in dependence on the flapping phase. The results are discussed in detail using the data of a single flight, whereas a comparison of some kinematic parameters obtained from different flights is given too.

  3. Independence of echo-threshold and echo-delay in the barn owl.

    Directory of Open Access Journals (Sweden)

    Brian S Nelson

    Full Text Available Despite their prevalence in nature, echoes are not perceived as events separate from the sounds arriving directly from an active source, until the echo's delay is long. We measured the head-saccades of barn owls and the responses of neurons in their auditory space-maps while presenting a long duration noise-burst and a simulated echo. Under this paradigm, there were two possible stimulus segments that could potentially signal the location of the echo. One was at the onset of the echo; the other, after the offset of the direct (leading sound, when only the echo was present. By lengthening the echo's duration, independently of its delay, spikes and saccades were evoked by the source of the echo even at delays that normally evoked saccades to only the direct source. An echo's location thus appears to be signaled by the neural response evoked after the offset of the direct sound.

  4. The GEMPAK Barnes interactive objective map analysis scheme. [General Meteorological Software Package

    Science.gov (United States)

    Koch, S. E.; Kocin, P. J.; Desjardins, M.

    1983-01-01

    The analysis scheme and meteorological applications of the GEMPAK data analysis and display software system developed by NASA are described. The program was devised to permit objective, versatile, and practical analysis of satellite meteorological data using a minicomputer and a display system with graphics capability. A data area can be selected within the data file for the globe, and data-sparse regions can be avoided. Distances between observations and the nearest observation points are calculated in order to avoid errors when determining synoptic weather conditions. The Barnes (1973) successive correction method is employed to restore the amplitude of small yet resolvable wavelengths suppressed in an initial filtering pass. The rms deviation is then calculated in relation to available measured data. Examples are provided of treatment of VISSR data from the GOES satellite and a study of the impact of incorrect cloud height data on synoptic weather field analysis.

  5. Cassia spectabilis (DC) Irwin et Barn: a promising traditional herb in health improvement.

    Science.gov (United States)

    Jothy, Subramanion L; Torey, Angeline; Darah, Ibrahim; Choong, Yee Siew; Saravanan, Dharmaraj; Chen, Yeng; Latha, Lachimanan Yoga; Deivanai, Subramanian; Sasidharan, Sreenivasan

    2012-08-29

    The genus Cassia, comprising about 600 species widely distributed worldwide is well known for its diverse biological and pharmacological properties. Cassia spectabilis (sin Senna spectabilis) (DC) Irwin et Barn (Fabaceae) is widely grown as an ornamental plant in tropical and subtropical areas. C. spectabilis has been commonly used in traditional medicine for many years. Information in the biomedical literature has indicated the presence of a variety of medicinally-important chemical constituents in C. spectabilis. Pharmacological studies by various groups of investigators have shown that C. spectabilis possesses significant biological activity, such as antibacterial, antibiofilm, antifungal and antioxidant properties. Beside this, toxicity studies of this plant have revealed no toxic effect on mice. In view of the immense medicinal importance of C. spectabilis, this review aimed at compiling all currently available information on C. spectabilis’s botany, phytochemistry, pharmacology, and mechanism of actions, toxicology and its ethnomedicinal uses.

  6. Reactor and method of operation

    Science.gov (United States)

    Wheeler, John A.

    1976-08-10

    A nuclear reactor having a flattened reactor activity curve across the reactor includes fuel extending over a lesser portion of the fuel channels in the central portion of the reactor than in the remainder of the reactor.

  7. Fan cooling of the resting area in a free stalls dairy barn.

    Science.gov (United States)

    Calegari, Ferdinando; Calamari, Luigi; Frazzi, Ermes

    2014-08-01

    This summer study evaluated the effect of providing additional fans (cooling) in the resting area within a free-stall dairy barn that had fans and sprinklers in the feeding area and paddock availability. Thirty cows were divided into two homogenous groups and kept in two pens: one had the resting area equipped with two fans (FAN) while no fans were added to the other resting area (CON). Microclimatic parameters, rectal temperature (RT), breathing rate (BR), milk yield, and milk pH traits were recorded. Time budgeting and the behaviour of the cows (time spent in the feeding area, standing and lying in other areas) were also recorded using digital video technology. Two slight-to-moderate heat waves were observed. During the hottest period the daily maximum temperature recorded was 33.5 °C and the daily maximum THI was 81.6. During this period, the BR and RT increased only slightly in both groups, with lower BR (n.s.) in FAN compared with CON. Milk yield was better maintained (n.s.) in FAN compared with CON during the hottest period. The FAN cows showed a greater (Pfree stalls (9.5 and 8.6 h/day in FAN and CON, respectively), whereas CON cows made greater (P<0.05) use of the paddock during evening and late evening hours. Consequently, the total daily lying time was 13.5 h/day in both groups. In conclusion, the results suggest that using fans in the resting area improves cow comfort, which increases use of the resting area. The lying time results also suggest that the benefits of providing ventilation in the resting area might be more evident in barns where there is no paddock.

  8. Morphometric characterisation of wing feathers of the barn owl Tyto alba pratincola and the pigeon Columba livia

    Directory of Open Access Journals (Sweden)

    Klaas Michael

    2007-11-01

    Full Text Available Abstract Background Owls are known for their silent flight. Even though there is some information available on the mechanisms that lead to a reduction of noise emission, neither the morphological basis, nor the biological mechanisms of the owl's silent flight are known. Therefore, we have initiated a systematic analysis of wing morphology in both a specialist, the barn owl, and a generalist, the pigeon. This report presents a comparison between the feathers of the barn owl and the pigeon and emphasise the specific characteristics of the owl's feathers on macroscopic and microscopic level. An understanding of the features and mechanisms underlying this silent flight might eventually be employed for aerodynamic purposes and lead to a new wing design in modern aircrafts. Results A variety of different feathers (six remiges and six coverts, taken from several specimen in either species, were investigated. Quantitative analysis of digital images and scanning electron microscopy were used for a morphometric characterisation. Although both species have comparable body weights, barn owl feathers were in general larger than pigeon feathers. For both species, the depth and the area of the outer vanes of the remiges were typically smaller than those of the inner vanes. This difference was more pronounced in the barn owl than in the pigeon. Owl feathers also had lesser radiates, longer pennula, and were more translucent than pigeon feathers. The two species achieved smooth edges and regular surfaces of the vanes by different construction principles: while the angles of attachment to the rachis and the length of the barbs was nearly constant for the barn owl, these parameters varied in the pigeon. We also present a quantitative description of several characteristic features of barn owl feathers, e.g., the serrations at the leading edge of the wing, the fringes at the edges of each feather, and the velvet-like dorsal surface. Conclusion The quantitative

  9. Starch gel and cellulose acetate electrophoretic analysis of allozyme frequencies in barn swallow (Hirundo rustica) populations at a dioxin contaminated site in northern Louisiana

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This study compared the genetic variability of Louisiana barn swallows at a dioxin-contaminated wetland to two reference populations. Allozyme frequencies,...

  10. A Stiff Man-Child Walking: Derrida’s Economy of Secrecy and Faulkner’s “Barn Burning”

    Directory of Open Access Journals (Sweden)

    Michael Wainwright

    2011-12-01

    Full Text Available Working from Jacques Derrida’s contentions about secrecy and authorial responsibility, and paying brief but specific attention to Charles Baudelaire’s “La fausse monnaie” (1869, as suggested by Derridean concerns over capitalist economics, this article studies the manner in which the inviolable and conditional secrets of William Faulkner’s “Barn Burning” (1938 reveal the poststructural tendencies avant la lettre of this leading American modernist.  While Faulkner scholars have focused on the ambivalent language and metaphors deployed in this short story, they have not formerly traced the manner in which “Barn Burning” incites a sense of deconstructive criticism, and have thereby failed to acknowledge Faulkner’s attendant authorial irresponsibility.  This article redresses this critical imbalance.

  11. Barn Owl pellets (Aves: Tyto furcata) reveal a higher mammalian richness in the Restinga de Jurubatiba National Park, Southeastern Brazil

    OpenAIRE

    2015-01-01

    The northern coast of the state of Rio de Janeiro harbors the largest coastal sandy plains (restingas) of southeastern Brazil, severely threatened due to recent human occupation. In this context, mammal inventories becomes urgent to support biodiversity conservation and management policies. This paper aims to update the knowledge on the mammalian species richness of Restinga de Jurubatiba National Park by analyzing pellets of the Barn owl Tyto furcata. The analyses of 4745 mammalian bone frag...

  12. Muscular Arrangement and Muscle Attachment Sites in the Cervical Region of the American Barn Owl (Tyto furcata pratincola)

    OpenAIRE

    2015-01-01

    Owls have the largest head rotation capability amongst vertebrates. Anatomical knowledge of the cervical region is needed to understand the mechanics of these extreme head movements. While data on the morphology of the cervical vertebrae of the barn owl have been provided, this study is aimed to provide an extensive description of the muscle arrangement and the attachment sites of the muscles on the owl's head-neck region. The major cervical muscles were identified by gross dissection of cada...

  13. Effects of triticale-based diets on finishing pig performance and pork quality in deep-bedded hoop barns.

    Science.gov (United States)

    Sullivan, Zebblin M; Honeyman, Mark S; Gibson, Lance R; Prusa, Ken J

    2007-07-01

    Effects of triticale diets on pig performance and pork quality were evaluated in summer and winter. Diets were: corn-soy, 40% triticale, or 80% triticale. Pigs (72kg) were fed 49d. Loins were evaluated for meat and fat quality and sensory evaluation. Average daily gain decreased as triticale inclusion increased (Ptriticale had least gain:feed ratio (Ptriticale diet had smallest loin muscle area (PTriticale fed to pigs in hoop barns slightly decreased growth without compromising pork quality.

  14. Evolutionary divergence in sexual signals: Insights from within and among barn swallow populations

    Science.gov (United States)

    Wilkins, Matthew Reed

    A wealth of studies across diverse animal groups indicate the importance of sexual selection in shaping phenotypes within and across breeding populations. In recent decades, much research has focused on how divergent sexual selection pressures among populations may lead to speciation. For my first dissertation chapter, I performed a literature review on the causes and consequences of evolutionary divergence in acoustic signals and developed the acoustic window conceptual framework for understanding the contributions of selection, genetic drift, and evolutionary constraint to signal divergence. Further, I found that sexual selection explains acoustic differences between recently diverged populations of the best-studied taxa. However, the relative contributions of ecological selection, sexual selection, and drift to acoustic divergence have not typically been considered within the same study systems. The remainder of my dissertation used the Northern Hemisphere-distributed barn swallow ( Hirundo rustica) species complex as a model system to study sender-receiver dynamics, intra- and intersexual selection pressures, and visual and acoustic signal interactions at the local scale, and signal divergence across populations at the global scale. From song recordings taken across 19 sampling sites, spanning five of six described subspecies, I demonstrated considerable conservation in song structure. However, temporal traits were highly divergent across subspecies, and in particular, the speed of the terminal trill of songs. In a detailed study of the multimodal communication system of the barn swallow (including visual and acoustic traits), I demonstrated that males and females use different types of signals to mediate competition and mate choice. One of the only exceptions to this rule was trill rate, which was also implicated in song divergence across populations. In order to test the function of trill rate in communication, I performed a two-year playback study within the

  15. Characterization of bioaerosols from dairy barns: reconstructing the puzzle of occupational respiratory diseases by using molecular approaches.

    Science.gov (United States)

    Blais Lecours, Pascale; Veillette, Marc; Marsolais, David; Duchaine, Caroline

    2012-05-01

    To understand the etiology of exposure-related diseases and to establish standards for reducing the risks associated with working in contaminated environments, the exact nature of the bioaerosol components must be defined. Molecular biology tools were used to evaluate airborne bacterial and, for the first time, archaeal content of dairy barns. Three air samplers were tested in each of the 13 barns sampled. Up to 10(6) archaeal and 10(8) bacterial 16S rRNA genes per m(3) of air were detected. Archaeal methanogens, mainly Methanobrevibacter species, were represented. Saccharopolyspora rectivirgula, the causative agent of farmer's lung, was quantified to up to 10(7) 16S rRNA genes per m(3) of air. In addition, a wide variety of bacterial agents were present in our air samples within the high airborne bioaerosol concentration range. Despite recommendations regarding hay preservation and baling conditions, farmers still develop an S. rectivirgula-specific humoral immune response, suggesting intense and continuous exposure. Our results demonstrate the complexity of bioaerosol components in dairy barns which could play a role in occupational respiratory diseases.

  16. Reactor Physics Programme

    Energy Technology Data Exchange (ETDEWEB)

    De Raedt, C

    2000-07-01

    The Reactor Physics and Department of SCK-CEN offers expertise in various areas of reactor physics, in particular in neutronics calculations, reactor dosimetry, reactor operation, reactor safety and control and non-destructive analysis on reactor fuel. This expertise is applied within the Reactor Physics and MYRRHA Research Department's own research projects in the VENUS critical facility, in the BR1 reactor and in the MYRRHA project (this project aims at designing a prototype Accelerator Driven System). Available expertise is also used in programmes external to the Department such as the reactor pressure steel vessel programme, the BR2 reactor dosimetry, and the preparation and interpretation of irradiation experiments. Progress and achievements in 1999 in the following areas are reported on: (1) investigations on the use of military plutonium in commercial power reactors; (2) neutron and gamma calculations performed for BR-2 and for other reactors; (3) the updating of neutron and gamma cross-section libraries; (4) the implementation of reactor codes; (6) the management of the UNIX workstations; and (6) fuel cycle studies.

  17. Two-fold Mellin-Barnes transforms of Usyukina-Davydychev functions

    Energy Technology Data Exchange (ETDEWEB)

    Kniehl, Bernd [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Kondrashuk, Igor [Univ. del Bio Bio, Chillan (Chile). Dept. de Ciencias Basicas; Bielefeld Univ. (Germany). Fakultaet fuer Physik; Notte-Cuello, Eduardo A. [Univ. de La Serena (Chile). Dept. de Matematicas; Parra-Ferrada, Ivan [Univ. del Bio Bio, Chillan (Chile). Facultad de Educacion y Humanidades; Rojas-Medar, Marko [Univ. del Bio Bio, Chillan (Chile). Dept. de Ciencias Basicas

    2013-04-15

    In our previous paper (Nucl.Phys.B 870 (2013) 243) we showed that multi-fold Mellin-Barnes (MB) transforms of the Usyukina-Davydychev (UD) functions may be reduced to two-fold MB transforms. The MB transforms were written there as polynomials of logarithms of ratios of squares of the external momenta with certain coefficients. We also showed that these coefficients have a combinatoric origin. In this paper we present an explicit formula for these coefficients. The procedure of recovering the coefficients is based on taking the double uni-form limit in certain series of smooth functions of two variables which is constructed according to a pre-determined iterative way. The result is obtained by using basic methods of mathematical analysis. We observe that the finiteness of the limit of this iterative chain of smooth functions should reflect itself in other mathematical constructions, too, since it is not related in any way to the explicit form of the MB transforms.

  18. Two-fold Mellin–Barnes transforms of Usyukina–Davydychev functions

    Energy Technology Data Exchange (ETDEWEB)

    Kniehl, Bernd A., E-mail: kniehl@desy.de [II. Institut für Theoretische Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); Kondrashuk, Igor [Grupo de Matemática Aplicada, Departamento de Ciencias Básicas, Universidad del Bío-Bío, Campus Fernando May, Casilla 447, Chillán (Chile); Fakultät für Physik, Universität Bielefeld, Universitätsstraße 25, 33615 Bielefeld (Germany); Notte-Cuello, Eduardo A. [Departamento de Matemáticas, Facultad de Ciencias, Universidad de La Serena, Av. Cisternas 1200, La Serena (Chile); Parra-Ferrada, Ivan [Carrera de Pedagogia en Matemática, Facultad de Educación y Humanidades, Universidad del Bío-Bío, Campus Castilla, Casilla 447, Chillán (Chile); Rojas-Medar, Marko [Grupo de Matemática Aplicada, Departamento de Ciencias Básicas, Universidad del Bío-Bío, Campus Fernando May, Casilla 447, Chillán (Chile)

    2013-11-01

    In our previous paper (Allendes et al., 2013 [10]), we showed that multi-fold Mellin–Barnes (MB) transforms of Usyukina–Davydychev (UD) functions may be reduced to two-fold MB transforms. The MB transforms were written there as polynomials of logarithms of ratios of squares of the external momenta with certain coefficients. We also showed that these coefficients have a combinatoric origin. In this paper, we present an explicit formula for these coefficients. The procedure of recovering the coefficients is based on taking the double-uniform limit in certain series of smooth functions of two variables which is constructed according to a pre-determined iterative way. The result is obtained by using basic methods of mathematical analysis. We observe that the finiteness of the limit of this iterative chain of smooth functions should reflect itself in other mathematical constructions, too, since it is not related in any way to the explicit form of the MB transforms. This finite double-uniform limit is represented in terms of a differential operator with respect to an auxiliary parameter which acts on the integrand of a certain two-fold MB integral. To demonstrate that our result is compatible with original representations of UD functions, we reproduce the integrands of these original integral representations by applying this differential operator to the integrand of the simple integral representation of the scalar triangle four-dimensional integral J(1,1,1−ε)

  19. The differential hippocampal phosphoproteome of Apodemus sylvaticus paralleling spatial memory retrieval in the Barnes maze.

    Science.gov (United States)

    Li, Lin; Csaszar, Edina; Szodorai, Edit; Patil, Sudarshan; Pollak, Arnold; Lubec, Gert

    2014-05-01

    Protein phosphorylation is a well-known and well-documented mechanism in memory processes. Although a large series of protein kinases involved in memory processes have been reported, information on phosphoproteins is limited. It was therefore the aim of the study to determine a partial and differential phosphoproteome along with the corresponding network in hippocampus of a wild caught mouse strain with excellent performance in several paradigms of spatial memory. Apodemus sylvaticus mice were trained in the Barnes maze, a non-invasive test system for spatial memory and untrained mice served as controls. Animals were sacrificed 6h following memory retrieval, hippocampi were taken, proteins extracted and in-solution digestion was carried out with subsequent iTRAQ double labelling. Phosphopeptides were enriched by a TiO2-based method and semi-quantified using two fragmentation principles on the LTQ-orbitrap Velos. In hippocampi of trained animals phosphopeptide levels representing signalling, neuronal, synaptosomal, cytoskeletal and metabolism proteins were at least twofold reduced or increased. Furthermore, a network revealing a link to pathways of ubiquitination, the androgen receptor, small GTPase Rab5 and MAPK signaling as well as synucleins was constructed. This work is relevant for interpretation of previous work and the design of future studies on protein phosphorylation in spatial memory.

  20. Solution to Bethe-Salpeter equation via Mellin-Barnes transform

    Energy Technology Data Exchange (ETDEWEB)

    Allendes, Pedro [Concepcion Univ. (Chile). Dept. de Fisica; Kniehl, Bernd [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Kondrashuk, Igor; Rojas Medar, Marko [Univ. del Bio-Bio, Chillan (Chile). Dept. de Ciencias Basicas; Notte Cuello, Eduardo A. [Univ. de La Serena (Chile). Facultad de Ciencias

    2012-06-15

    We consider Mellin-Barnes transform of triangle ladder-like scalar diagram in d=4 dimensions. It is shown how multi-fold MB transform of the momentum integral corresponding to any number of rungs is reduced to two-fold MB transform. For this purpose we use Belokurov-Usyukina reduction method for four-dimensional scalar integrals in the position space. The result is represented in terms of Euler {psi}-function and its derivatives. We derive new formulas for MB two-fold integration in the complex planes of two complex variables. We demonstrate that these formulas solve Bethe-Salpeter equation. We comment on further applications of solution to Bethe-Salpeter equation for vertices in N=4 supersymmetric Yang-Mills theory. We show that the recursive property of MB transforms observed in the present work for that kind of diagrams has nothing to do with quantum field theory, theory of integral transforms, or with theory of polylogarithms in general, but has an origin in a simple recursive property for smooth functions which can be shown by using basic methods of mathematical analysis.

  1. Solution to Bethe-Salpeter equation via Mellin-Barnes transform

    CERN Document Server

    Allendes, Pedro; Kondrashuk, Igor; Cuello, Eduardo A Notte; Medar, Marko Rojas

    2012-01-01

    We consider Mellin-Barnes transform of triangle ladder-like scalar diagram in d=4 dimensions. It is shown how multi-fold MB transform of the momentum integral corresponding to any number of rungs is reduced to two-fold MB transform. For this purpose we use Belokurov-Usyukina reduction method for four-dimensional scalar integrals in the position space. The result is represented in terms of Euler psi-function and its derivatives. We derive new formulas for MB two-fold integration in the complex planes of two complex variables. We demonstrate that these formulas solve Bethe-Salpeter equation. We comment on further applications of solution to Bethe-Salpeter equation for vertices in N=4 supersymmetric Yang-Mills theory. We show that the recursive property of MB transforms observed in the present work for that kind of diagrams has nothing to do with quantum field theory, theory of integral transforms, or with theory of polylogarithms in general, but has an origin in a simple recursive property for smooth functions ...

  2. A GPU accelerated Barnes-Hut tree code for FLASH4

    Science.gov (United States)

    Lukat, Gunther; Banerjee, Robi

    2016-05-01

    We present a GPU accelerated CUDA-C implementation of the Barnes Hut (BH) tree code for calculating the gravitational potential on octree adaptive meshes. The tree code algorithm is implemented within the FLASH4 adaptive mesh refinement (AMR) code framework and therefore fully MPI parallel. We describe the algorithm and present test results that demonstrate its accuracy and performance in comparison to the algorithms available in the current FLASH4 version. We use a MacLaurin spheroid to test the accuracy of our new implementation and use spherical, collapsing cloud cores with effective AMR to carry out performance tests also in comparison with previous gravity solvers. Depending on the setup and the GPU/CPU ratio, we find a speedup for the gravity unit of at least a factor of 3 and up to 60 in comparison to the gravity solvers implemented in the FLASH4 code. We find an overall speedup factor for full simulations of at least factor 1.6 up to a factor of 10.

  3. A GPU accelerated Barnes-Hut Tree Code for FLASH4

    CERN Document Server

    Lukat, Gunther

    2016-01-01

    We present a GPU accelerated CUDA-C implementation of the Barnes Hut (BH) tree code for calculating the gravita- tional potential on octree adaptive meshes. The tree code algorithm is implemented within the FLASH4 adaptive mesh refinement (AMR) code framework and therefore fully MPI parallel. We describe the algorithm and present test results that demonstrate its accuracy and performance in comparison to the algorithms available in the current FLASH4 version. We use a MacLaurin spheroid to test the accuracy of our new implementation and use spherical, collapsing cloud cores with effective AMR to carry out performance tests also in comparison with previous gravity solvers. Depending on the setup and the GPU/CPU ratio, we find a speedup for the gravity unit of at least a factor of 3 and up to 60 in comparison to the gravity solvers implemented in the FLASH4 code. We find an overall speedup factor for full simulations of at least factor 1.6 up to a factor of 10

  4. Quantitative genetics of migration syndromes: a study of two barn swallow populations.

    Science.gov (United States)

    Teplitsky, C; Mouawad, N G; Balbontin, J; De Lope, F; Møller, A P

    2011-09-01

    Migration is a complex trait although little is known about genetic correlations between traits involved in such migration syndromes. To assess the migratory responses to climate change, we need information on genetic constraints on evolutionary potential of arrival dates in migratory birds. Using two long-term data sets on barn swallows Hirundo rustica (from Spain and Denmark), we show for the first time in wild populations that spring arrival dates are phenotypically and genetically correlated with morphological and life history traits. In the Danish population, length of outermost tail feathers and wing length were negatively genetically correlated with arrival date. In the Spanish population, we found a negative genetic correlation between arrival date and time elapsed between arrival date and laying date, constraining response to selection that favours both early arrival and shorter delays. This results in a decreased rate of adaptation, not because of constraints on arrival date, but constraints on delay before breeding, that is, a trait that can be equally important in the context of climate change.

  5. A link between eumelanism and calcium physiology in the barn owl

    Science.gov (United States)

    Roulin, Alexandre; Dauwe, Tom; Blust, Ronny; Eens, Marcel; Beaud, Michel

    2006-09-01

    In many animals, melanin-based coloration is strongly heritable and is largely insensitive to the environment and body condition. According to the handicap principle, such a trait may not reveal individual quality because the production of different melanin-based colorations often entails similar costs. However, a recent study showed that the production of eumelanin pigments requires relatively large amounts of calcium, potentially implying that melanin-based coloration is associated with physiological processes requiring calcium. If this is the case, eumelanism may be traded-off against other metabolic processes that require the same elements. We used a correlative approach to examine, for the first time, this proposition in the barn owl, a species in which individuals vary in the amount, size, and blackness of eumelanic spots. For this purpose, we measured calcium concentration in the left humerus of 85 dead owls. Results showed that the humeri of heavily spotted individuals had a higher concentration of calcium. This suggests either that plumage spottiness signals the ability to absorb calcium from the diet for both eumelanin production and storage in bones, or that lightly spotted individuals use more calcium for metabolic processes at the expense of calcium storage in bones. Our study supports the idea that eumelanin-based coloration is associated with a number of physiological processes requiring calcium.

  6. In vivo Recordings from Low-Frequency Nucleus Laminaris in the Barn Owl.

    Science.gov (United States)

    Palanca-Castan, Nicolas; Köppl, Christine

    2015-01-01

    Localization of sound sources relies on 2 main binaural cues: interaural time differences (ITD) and interaural level differences. ITD computing is first carried out in tonotopically organized areas of the brainstem nucleus laminaris (NL) in birds and the medial superior olive (MSO) in mammals. The specific way in which ITD are derived was long assumed to conform to a delay line model in which arrays of systematically arranged cells create a representation of auditory space, with different cells responding maximally to specific ITD. This model conforms in many details to the particular case of the high-frequency regions (above 3 kHz) in the barn owl NL. However, data from recent studies in mammals are not consistent with a delay line model. A new model has been suggested in which neurons are not topographically arranged with respect to ITD and coding occurs through assessment of the overall response of 2 large neuron populations – 1 in each brainstem hemisphere. Currently available data comprise mainly low-frequency (owl and compare it to data from other avian and mammalian studies. Our data are consistent with a delay line model, so differences between ITD processing systems are more likely to have originated through divergent evolution of different vertebrate groups.

  7. “And all the windows, great and small”. Finestre in Nightwood di Djuna Barnes

    Directory of Open Access Journals (Sweden)

    Francesca Chiappini

    2015-01-01

    Full Text Available As a recurring subject and powerful symbol, the window dominates the female literary and artistic imagery of the twentieth century. It has been developed into mirror, photograph or painting, according to the writer’s needs, yet the basic shape of the frame is always retraceable. Among late modernist and postmodernist women writers, Djuna Barnes explores in detail the structural resources of this literary device. Although she already understands the potential of the frame in her early career as a journalist, she mostly challenges its extents of versatility in Nightwood (1936. Its crucial moments – either flashing epiphanies or missed catharsis – involve the physical presence of a window, which embodies a powerful narrative agent; more than mere symbol, it is active at several levels. Thematically, doors and windows, pictures and mirrors, play an important cohesive role. At a deeper stage of analysis, the structure of the novel itself is shored up by doors and windows, since the setting is essentially organized into indoors and outdoors scenes; windows and doors allow the characters to move between these two dimensions. On the metaphorical level, windows and doors represent a communicative channel; a room-door opening suggests the access to one’s inner life, whereas a shut window denies any chance of dialogue. However, all the characters seem to be too absorbed by their obsessions to realize such communicative potential, and rather meander uselessly in their mental frames.

  8. Misting and fan cooling of the rest area in a dairy barn

    Science.gov (United States)

    Calegari, Ferdinando; Calamari, Luigi; Frazzi, Ermes

    2012-03-01

    This summer study aimed to evaluate the effect on dairy cows, kept in a free stall barn equipped with fans and sprinklers in the feeding area, of the delivery rate of misters in a cooling system in rest areas with different bedding materials. Thirty cows were divided into two homogenous groups according to milk yield and kept in two pens: one had beds with sand (SAMM) while the other had straw (STLM). Each pen was equipped with 2 fans (Ø 70 cm, 0.50 kW) and 2 misters (delivery rate of 11.2 and 22.5 L/h in STLM and SAMM, respectively) in the rest area. Microclimatic parameters, rectal temperature (RT), breathing rate (BR), milk yield, and some milk traits were recorded. Behavioural routines of the cows (standing and lying) were also continuously recorded during the hotter days. During the trial, two mild-moderate heat waves were observed. During these hotter periods, the daily maximum temperature recorded in the rest areas was 28.9 in SAMM and 31.2 in STLM, and the daily maximum THI was 78.2 in SAMM and 81.5 in STLM. In these periods, the cows in SAMM compared with those in STLM showed lower BR ( P fans plus misters with mild wetting in rest areas with sand as bedding materials reduces heat stress and improves cow comfort.

  9. Efficient Implementation of the Barnes-Hut Octree Algorithm for Monte Carlo Simulations of Charged Systems

    CERN Document Server

    Gan, Zecheng

    2013-01-01

    Computer simulation with Monte Carlo is an important tool to investigate the function and equilibrium properties of many systems with biological and soft matter materials solvable in solvents. The appropriate treatment of long-range electrostatic interaction is essential for these charged systems, but remains a challenging problem for large-scale simulations. We have developed an efficient Barnes-Hut treecode algorithm for electrostatic evaluation in Monte Carlo simulations of Coulomb many-body systems. The algorithm is based on a divide-and-conquer strategy and fast update of the octree data structure in each trial move through a local adjustment procedure. We test the accuracy of the tree algorithm, and use it to computer simulations of electric double layer near a spherical interface. It has been shown that the computational cost of the Monte Carlo method with treecode acceleration scales as $\\log N$ in each move. For a typical system with ten thousand particles, by using the new algorithm, the speed has b...

  10. LMFBR type reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami, Hiroto

    1995-02-07

    A reactor container of the present invention has a structure that the reactor container is entirely at the same temperature as that at the inlet of the reactor and, a hot pool is incorporated therein, and the reactor container has is entirely at the same temperature and has substantially uniform temperature follow-up property transiently. Namely, if the temperature at the inlet of the reactor core changes, the temperature of the entire reactor container changes following this change, but no great temperature gradient is caused in the axial direction and no great heat stresses due to axial temperature distribution is caused. Occurrence of thermal stresses caused by the axial temperature distribution can be suppressed to improve the reliability of the reactor container. In addition, since the laying of the reactor inlet pipelines over the inside of the reactor is eliminated, the reactor container is made compact and the heat shielding structures above the reactor and a protection structure of container walls are simplified. Further, secondary coolants are filled to the outside of the reactor container to simplify the shieldings. The combined effects described above can improve economical property and reliability. (N.H.).

  11. Light water reactor safety

    CERN Document Server

    Pershagen, B

    2013-01-01

    This book describes the principles and practices of reactor safety as applied to the design, regulation and operation of light water reactors, combining a historical approach with an up-to-date account of the safety, technology and operating experience of both pressurized water reactors and boiling water reactors. The introductory chapters set out the basic facts upon which the safety of light water reactors depend. The central section is devoted to the methods and results of safety analysis. The accidents at Three Mile Island and Chernobyl are reviewed and their implications for light wate

  12. Nuclear reactor physics

    CERN Document Server

    Stacey, Weston M

    2010-01-01

    Nuclear reactor physics is the core discipline of nuclear engineering. Nuclear reactors now account for a significant portion of the electrical power generated worldwide, and new power reactors with improved fuel cycles are being developed. At the same time, the past few decades have seen an ever-increasing number of industrial, medical, military, and research applications for nuclear reactors. The second edition of this successful comprehensive textbook and reference on basic and advanced nuclear reactor physics has been completely updated, revised and enlarged to include the latest developme

  13. Spinning fluids reactor

    Science.gov (United States)

    Miller, Jan D; Hupka, Jan; Aranowski, Robert

    2012-11-20

    A spinning fluids reactor, includes a reactor body (24) having a circular cross-section and a fluid contactor screen (26) within the reactor body (24). The fluid contactor screen (26) having a plurality of apertures and a circular cross-section concentric with the reactor body (24) for a length thus forming an inner volume (28) bound by the fluid contactor screen (26) and an outer volume (30) bound by the reactor body (24) and the fluid contactor screen (26). A primary inlet (20) can be operatively connected to the reactor body (24) and can be configured to produce flow-through first spinning flow of a first fluid within the inner volume (28). A secondary inlet (22) can similarly be operatively connected to the reactor body (24) and can be configured to produce a second flow of a second fluid within the outer volume (30) which is optionally spinning.

  14. Biobanken i Den norske mor og barn undersøkelsen

    Directory of Open Access Journals (Sweden)

    Kjersti S. Rønningen

    2009-10-01

    Full Text Available  Biobanker for langtidslagring av biologisk materiale blir en viktigere og viktigere del av epidemiologiske studier. I planleggingen av en biobank er det en rekke avgjørelser som må tas for å sikre best mulig oppslutning både med hensyn til å få inn så mange prøver som mulig og å oppnå best mulig prøvekvalitet både på kort og lang sikt. Den norske mor og barn undersøkelsen (MoBa skal inkludere 100 000 svangerskap og følge mor, far og barn i lang tid fremover. Innsamlingen av data startet i ett fylke i 1999, og omfatter i dag hele landet. Siden det tas blodprøver to ganger fra hver kvinne, blodprøve fra far og navlesnorsblod frabarna, betydde dette at Biobanken for MoBa måtte planlegges for å kunne motta og langtidslagre over 380 000 prøvesett. Ved Biobanken ved Nasjonalt folkehelseinstitutt lagres fullblod, plasma, urin, DNA og spesialrør til senere RNA isolering. Rekruttering til MoBa foregår ved 52 av landets sykehus. Prøvene sendes per post til Biobanken ved Folkehelseinstituttet for prosessering. Per januar 2006 er over 200 000 prøvesett lagret ved Biobanken. Denne artikkelen gir en kortfattet oversikt over oppbyggingen av Biobanken og logistikken knyttet til innsamlingen av biologisk materiale, fra blodet tappes til det er sikkert lagret og klart til å tas ut på et senere tidspunkt, kanskje mange år inn i fremtiden.The biobank in The Norwegian Mother and Child Cohort Study.Long term storage of biological material is becoming a critical component of many epidemiological studies. In designing specimen repositories, efforts need to be made to balance future needs for samples with logistical constraints necessary to process and store samples in a timely fashion. The Norwegian Mother and Child Cohort Study was started in 1999 and aims at including 100,000 pregnancies, and will follow mother, father and child for many years to come. The Biobank was faced with the challenge to receive and store over 380,000 biological

  15. Cooling systems of the resting area in free stall dairy barn

    Science.gov (United States)

    Calegari, F.; Calamari, L.; Frazzi, E.

    2016-04-01

    A study during the summer season evaluated the effect of different cooling systems on behavioral and productive responses of Italian Friesian dairy cows kept in an experimental-free stall barn located in the Po Valley in Italy. The study involved 30 lactating dairy cows subdivided into two groups kept in two pens with external hard court paddock in each free stall. The same cooling system was applied in the feeding area in both pens. A different cooling system in the resting area was applied to the two pens: in the pen SW, the resting area was equipped with fans and misters; in the other, there was simple ventilation (SV). Breathing rate, rectal temperature, milk yield, and milk characteristics (fat, protein, and somatic cell count) were measured. Behavioral activities (standing and lying cows in the different areas, as well as the animals in the feed bunk) were recorded. Mild to moderate heat waves during the trial were observed. On average, the breathing rate was numerically greater in SV compared with SW cows (60.2 and 55.8 breath/min, respectively), and mean rectal temperature remained below 39 °C in both groups during the trial (on average 38.7 and 38.8 °C in SV and SW, respectively. During the hotter periods of the trial, the time spent lying indoor in the free stall was greater in SW (11.8 h/day) than SV (10.7 h/day). Conversely, the time spent standing indoor without feeding was greater in SV (4.3 h/day) than SW (3.8 h/day). Milk yield was slightly better maintained during hotter period in SW compared with SV and somatic cell count was also slightly greater in the former. In conclusion, the adoption of the cooling system by means of evaporative cooling also in the resting area reduces the alteration of time budget caused by heat stress.

  16. Sexual dimorphism in melanin pigmentation, feather coloration and its heritability in the barn swallow (Hirundo rustica).

    Science.gov (United States)

    Saino, Nicola; Romano, Maria; Rubolini, Diego; Teplitsky, Celine; Ambrosini, Roberto; Caprioli, Manuela; Canova, Luca; Wakamatsu, Kazumasa

    2013-01-01

    Melanin is the main pigment in animal coloration and considerable variation in the concentrations of the two melanin forms (pheo- and eumlanin) in pigmented tissues exists among populations and individuals. Melanin-based coloration is receiving increasing attention particularly in socio-sexual communication contexts because the melanocortin system has been hypothesized to provide a mechanistic basis for covariation between coloration and fitness traits. However, with few notable exceptions, little detailed information is available on inter-individual and inter-population variation in melanin pigmentation and on its environmental, genetic and ontogenetic components. Here, we investigate melanin-based coloration in an Italian population of a passerine bird, the barn swallow (Hirundo rustica rustica), its sex- and age-related variation, and heritability. The concentrations of eu- and pheomelanin in the throat (brown) and belly (white-to-brownish) feathers differed between sexes but not according to age. The relative concentration of either melanin (Pheo:Eu) differed between sexes in throat but not in belly feathers, and the concentrations in males compared to females were larger in belly than in throat feathers. There were weak correlations between the concentrations of melanins within as well as among plumage regions. Coloration of belly feathers was predicted by the concentration of both melanins whereas coloration of throat feathers was only predicted by pheomelanin in females. In addition, Pheo:Eu predicted coloration of throat feathers in females and that of belly feathers in males. Finally, we found high heritability of color of throat feathers. Melanization was found to differ from that recorded in Hirundo rustica rustica from Scotland or from H. r. erythrogaster from North America. Hence, present results show that pigmentation strategies vary in a complex manner according to sex and plumage region, and also among geographical populations, potentially

  17. Barn owl feathers as biomonitors of mercury: sources of variation in sampling procedures.

    Science.gov (United States)

    Roque, Inês; Lourenço, Rui; Marques, Ana; Coelho, João Pedro; Coelho, Cláudia; Pereira, Eduarda; Rabaça, João E; Roulin, Alexandre

    2016-04-01

    Given their central role in mercury (Hg) excretion and suitability as reservoirs, bird feathers are useful Hg biomonitors. Nevertheless, the interpretation of Hg concentrations is still questioned as a result of a poor knowledge of feather physiology and mechanisms affecting Hg deposition. Given the constraints of feather availability to ecotoxicological studies, we tested the effect of intra-individual differences in Hg concentrations according to feather type (body vs. flight feathers), position in the wing and size (mass and length) in order to understand how these factors could affect Hg estimates. We measured Hg concentration of 154 feathers from 28 un-moulted barn owls (Tyto alba), collected dead on roadsides. Median Hg concentration was 0.45 (0.076-4.5) mg kg(-1) in body feathers, 0.44 (0.040-4.9) mg kg(-1) in primary and 0.60 (0.042-4.7) mg kg(-1) in secondary feathers, and we found a poor effect of feather type on intra-individual Hg levels. We also found a negative effect of wing feather mass on Hg concentration but not of feather length and of its position in the wing. We hypothesize that differences in feather growth rate may be the main driver of between-feather differences in Hg concentrations, which can have implications in the interpretation of Hg concentrations in feathers. Finally, we recommend that, whenever possible, several feathers from the same individual should be analysed. The five innermost primaries have lowest mean deviations to both between-feather and intra-individual mean Hg concentration and thus should be selected under restrictive sampling scenarios.

  18. Klatring i trær og hyttebygging: - om barns lek og lekesteder ute

    Directory of Open Access Journals (Sweden)

    Merete Lund Fasting

    2015-07-01

    Full Text Available Abstract: This article describes 10 year old children`s play in nature during school hours. However, my result does equally reflect on children in kindergarden as well. Observation and conversation was used as methods as well as pictures. The children’s play in the trees and building huts was conducted in groups, and their communication was nonverbal with each other and with the nature. However; the girls reveal that they enjoy their conversations while being in the tree. The children often play at the same place over and over. This is significant to the evolution of the play and the children’s communication with their places in nature.Sammendrag: Denne artikkelen omhandler 10 år gamle barns lek på natursteder i skoletida. Selv om studien omhandler 10 åringer så kan kunnskapen den frembringer også være viktig for å forstå barnehagebarns lek og tilknytning til sine lekesteder i barnehagen. Metodene som ble brukt for å undersøke barnas lek var observasjoner og samtaler med barna, i tillegg til fotografier. Barnas lek i trærne og i hyttebyggingen karakteriseres ved at de er flere sammen, og barna har en kroppslig dialog med hverandre og omgivelsene i leken. Barna snakker i liten grad sammen om leken og hvordan de skal leke; deres kommunikasjon er hovedsakelig nonverbal. Men når jentene sitter i treet forteller de meg at de liker å sitte og snakke. Barna leker på steder hvor de har vært mye før, og dette har en betydning for barnas lek og barnas kommunikasjon med deres steder.

  19. A trade-off between reproduction and feather growth in the barn swallow (Hirundo rustica.

    Directory of Open Access Journals (Sweden)

    Nicola Saino

    Full Text Available Physiological trade-offs mediated by limiting energy, resources or time constrain the simultaneous expression of major functions and can lead to the evolution of temporal separation between demanding activities. In birds, plumage renewal is a demanding activity, which accomplishes fundamental functions, such as allowing thermal insulation, aerodynamics and socio-sexual signaling. Feather renewal is a very expensive and disabling process, and molt is often partitioned from breeding and migration. However, trade-offs between feather renewal and breeding have been only sparsely studied. In barn swallows (Hirundo rustica breeding in Italy and undergoing molt during wintering in sub-Saharan Africa, we studied this trade-off by removing a tail feather from a large sample of individuals and analyzing growth bar width, reflecting feather growth rate, and length of the growing replacement feather in relation to the stage in the breeding cycle at removal and clutch size. Growth bar width of females and length of the growing replacement feather of both sexes were smaller when the original feather had been removed after clutch initiation. Importantly, in females both growth bar width and replacement feather length were negatively predicted by clutch size, and more strongly so for large clutches and when feather removal occurred immediately after clutch completion. Hence, we found strong, coherent evidence for a trade-off between reproduction, and laying effort in particular, and the ability to generate new feathers. These results support the hypothesis that the derived condition of molting during wintering in long-distance migrants is maintained by the costs of overlapping breeding and molt.

  20. Cooling systems of the resting area in free stall dairy barn.

    Science.gov (United States)

    Calegari, F; Calamari, L; Frazzi, E

    2016-04-01

    A study during the summer season evaluated the effect of different cooling systems on behavioral and productive responses of Italian Friesian dairy cows kept in an experimental-free stall barn located in the Po Valley in Italy. The study involved 30 lactating dairy cows subdivided into two groups kept in two pens with external hard court paddock in each free stall. The same cooling system was applied in the feeding area in both pens. A different cooling system in the resting area was applied to the two pens: in the pen SW, the resting area was equipped with fans and misters; in the other, there was simple ventilation (SV). Breathing rate, rectal temperature, milk yield, and milk characteristics (fat, protein, and somatic cell count) were measured. Behavioral activities (standing and lying cows in the different areas, as well as the animals in the feed bunk) were recorded. Mild to moderate heat waves during the trial were observed. On average, the breathing rate was numerically greater in SV compared with SW cows (60.2 and 55.8 breath/min, respectively), and mean rectal temperature remained below 39 °C in both groups during the trial (on average 38.7 and 38.8 °C in SV and SW, respectively. During the hotter periods of the trial, the time spent lying indoor in the free stall was greater in SW (11.8 h/day) than SV (10.7 h/day). Conversely, the time spent standing indoor without feeding was greater in SV (4.3 h/day) than SW (3.8 h/day). Milk yield was slightly better maintained during hotter period in SW compared with SV and somatic cell count was also slightly greater in the former. In conclusion, the adoption of the cooling system by means of evaporative cooling also in the resting area reduces the alteration of time budget caused by heat stress.

  1. Effect of summer grazing on welfare of dairy cows reared in mountain tie-stall barns

    Directory of Open Access Journals (Sweden)

    Simonetta Dovier

    2010-09-01

    Full Text Available Traditional mountain farms have an important economic, social and environmental role. The Alps management system for dairy cows consists of animals kept indoors from autumn to spring, mostly in tie-stalls, and moved to mountain pasture in summer. The aim of our study was to assess the effect of mountain summer grazing on the welfare of dairy cows housed in tie-stall barns. Twenty-four farms were considered. In twelve of them, animals were reared in tie-stalls and moved to mountain pasture for three months in summer; they were visited three times: (i four weeks before grazing during the indoor period in the stall; (ii about three weeks after the start of grazing; and (iii in the stall, in autumn, at least three weeks after returning from grazing. The other twelve farms kept the animals in tie-stalls all year; they were visited once in autumn. Data were collected following a protocol that considers animal-based measures and structure information on the basis of Quality Welfare Consortium® indications. Data allowed the calculation of both the Animal Needs Index score (ANI 35L and an overall assessment of the cows’ welfare obtained from three general aspects: housing, animal’s physical condition, and animal’s behaviour. Summer grazing had a significant positive effect on injuries, lameness and animal’s rising duration but a negative effect on faeces consistency. Moreover, a reduction of tongue playing was observed. The ANI 35L and the overall assessment did not show significant differences linked to summer grazing, which tended to have a positive but temporary effect on animal behaviour.

  2. In vitro production of tumor necrosis factor-alpha by human monocytes stimulated with lipopolysaccharide is positively correlated with increased blood monocytes after exposure to a swine barn.

    Science.gov (United States)

    Willson, P J; Khozani, T Talaei; Juurlink, B H J; Senthilselvan, A; Rennie, D C; Gerdts, V; Gawaziuk, J; Schneberger, D; Burch, Lauranell H; Dosman, J A

    2008-01-01

    Recently there has been interest in the air quality in and around intensive livestock production facilities, such as modern swine production barns, where agricultural workers and surrounding residents may be exposed to elevated levels of organic dusts. The health effects of these exposures are not completely understood. The study that is reported here is a component of a larger investigation of the relationships among the acute effects of high-concentration endotoxin exposure (swine barn dust), polymorphisms in the TLR4 gene, and respiratory outcomes following exposure to swine confinement buildings. The relationships among a mediator of acute lung inflammation, tumor necrosis factor alpha (TNF-alpha), and clinical responses to acute swine barn exposure were characterized. Analysis of the results showed that in vitro stimulation of human monocytes with as little as 1 ng/ml of lipopolysaccharide (LPS) produced a significant increase in the monocytes that produced TNF-alpha. Although the proportion of TNF-alpha-positive monocytes after in vitro stimulation with 1 ng/ml of LPS was not associated with gender or TLR4 genotype, it was positively associated with the concentration of monocytes in blood after barn exposure. Thus, these two responses to different forms of LPS exposure are significantly correlated, and more responsive monocytes in vitro indicate a forthcoming relative monocytosis, post barn exposure, which may initiate a cascade of chronic inflammation.

  3. Reactor Vessel Surveillance Program for Advanced Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Kyeong-Hoon; Kim, Tae-Wan; Lee, Gyu-Mahn; Kim, Jong-Wook; Park, Keun-Bae; Kim, Keung-Koo

    2008-10-15

    This report provides the design requirements of an integral type reactor vessel surveillance program for an integral type reactor in accordance with the requirements of Korean MEST (Ministry of Education, Science and Technology Development) Notice 2008-18. This report covers the requirements for the design of surveillance capsule assemblies including their test specimens, test block materials, handling tools, and monitors of the surveillance capsule neutron fluence and temperature. In addition, this report provides design requirements for the program for irradiation surveillance of reactor vessel materials, a layout of specimens and monitors in the surveillance capsule, procedures of installation and retrieval of the surveillance capsule assemblies, and the layout of the surveillance capsule assemblies in the reactor.

  4. Clock gene variation is associated with breeding phenology and maybe under directional selection in the migratory barn swallow.

    Directory of Open Access Journals (Sweden)

    Manuela Caprioli

    Full Text Available BACKGROUND: In diverse taxa, photoperiodic responses that cause seasonal physiological and behavioural shifts are controlled by genes, including the vertebrate Clock orthologues, that encode for circadian oscillator mechanisms. While the genetic network behind circadian rhythms is well described, relatively few reports exist of the phenological consequences of and selection on Clock genes in the wild. Here, we investigated variation in breeding phenology in relation to Clock genetic diversity in a long-distance migratory bird, the barn swallow (Hirundo rustica. METHODOLOGY/PRINCIPAL FINDINGS: In a sample of 922 adult barn swallows from a single population breeding in Italy we found one very common (Q(7 and three rare (Q(5, Q(6, Q(8 length variants of a functionally significant polyglutamine repeat. Rare (2.9% Q(7/Q(8 heterozygous females, but not males, bred significantly later than common (91.5% Q(7/Q(7 females, consistent with the expectation that 'long' alleles cause late breeding, as observed in a resident population of another bird species. Because breeding date depends on arrival date from migration, present results suggest that the association between breeding date and Clock might be mediated by migration phenology. In addition, fecundity selection appears to be operating against Q(7/Q(8 because late migrating/breeding swallows have fewer clutches per season, and late breeding has additional negative selection effects via reduced offspring longevity. Genotype frequencies varied marginally non-significantly with age, as Q(7/Q(8 frequency showed a 4-fold reduction in old individuals. This result suggests negative viability selection against Q(7/Q(8, possibly mediated by costs of late breeding. CONCLUSIONS/SIGNIFICANCE: This is the first study of migratory birds showing an association between breeding phenology and Clock genotype and suggesting that negative selection occurs on a phenologically deviant genotype. Low polymorphism at Clock may

  5. Sexual Dimorphism and Population Differences in Structural Properties of Barn Swallow (Hirundo rustica Wing and Tail Feathers.

    Directory of Open Access Journals (Sweden)

    Péter L Pap

    Full Text Available Sexual selection and aerodynamic forces affecting structural properties of the flight feathers of birds are poorly understood. Here, we compared the structural features of the innermost primary wing feather (P1 and the sexually dimorphic outermost (Ta6 and monomorphic second outermost (Ta5 tail feathers of barn swallows (Hirundo rustica from a Romanian population to investigate how sexual selection and resistance to aerodynamic forces affect structural differences among these feathers. Furthermore, we compared structural properties of Ta6 of barn swallows from six European populations. Finally, we determined the relationship between feather growth bars width (GBW and the structural properties of tail feathers. The structure of P1 indicates strong resistance against aerodynamic forces, while the narrow rachis, low vane density and low bending stiffness of tail feathers suggest reduced resistance against airflow. The highly elongated Ta6 is characterized by structural modifications such as large rachis width and increased barbule density in relation to the less elongated Ta5, which can be explained by increased length and/or high aerodynamic forces acting at the leading tail edge. However, these changes in Ta6 structure do not allow for full compensation of elongation, as reflected by the reduced bending stiffness of Ta6. Ta6 elongation in males resulted in feathers with reduced resistance, as shown by the low barb density and reduced bending stiffness compared to females. The inconsistency in sexual dimorphism and in change in quality traits of Ta6 among six European populations shows that multiple factors may contribute to shaping population differences. In general, the difference in quality traits between tail feathers cannot be explained by the GBW of feathers. Our results show that the material and structural properties of wing and tail feathers of barn swallows change as a result of aerodynamic forces and sexual selection, although the

  6. Natural selection in a postglacial range expansion: the case of the colour cline in the European barn owl.

    Science.gov (United States)

    Antoniazza, Sylvain; Kanitz, Ricardo; Neuenschwander, Samuel; Burri, Reto; Gaigher, Arnaud; Roulin, Alexandre; Goudet, Jérôme

    2014-11-01

    Gradients of variation--or clines--have always intrigued biologists. Classically, they have been interpreted as the outcomes of antagonistic interactions between selection and gene flow. Alternatively, clines may also establish neutrally with isolation by distance (IBD) or secondary contact between previously isolated populations. The relative importance of natural selection and these two neutral processes in the establishment of clinal variation can be tested by comparing genetic differentiation at neutral genetic markers and at the studied trait. A third neutral process, surfing of a newly arisen mutation during the colonization of a new habitat, is more difficult to test. Here, we designed a spatially explicit approximate Bayesian computation (ABC) simulation framework to evaluate whether the strong cline in the genetically based reddish coloration observed in the European barn owl (Tyto alba) arose as a by-product of a range expansion or whether selection has to be invoked to explain this colour cline, for which we have previously ruled out the actions of IBD or secondary contact. Using ABC simulations and genetic data on 390 individuals from 20 locations genotyped at 22 microsatellites loci, we first determined how barn owls colonized Europe after the last glaciation. Using these results in new simulations on the evolution of the colour phenotype, and assuming various genetic architectures for the colour trait, we demonstrate that the observed colour cline cannot be due to the surfing of a neutral mutation. Taking advantage of spatially explicit ABC, which proved to be a powerful method to disentangle the respective roles of selection and drift in range expansions, we conclude that the formation of the colour cline observed in the barn owl must be due to natural selection.

  7. Measurement of heat stress conditions at cow level and comparison to climate conditions at stationary locations inside a dairy barn.

    Science.gov (United States)

    Schüller, Laura K; Heuwieser, Wolfgang

    2016-08-01

    The objectives of this study were to examine heat stress conditions at cow level and to investigate the relationship to the climate conditions at 5 different stationary locations inside a dairy barn. In addition, we compared the climate conditions at cow level between primiparous and multiparous cows for a period of 1 week after regrouping. The temperature-humidity index (THI) differed significantly between all stationary loggers. The lowest THI was measured at the window logger in the experimental stall and the highest THI was measured at the central logger in the experimental stall. The THI at the mobile cow loggers was 2·33 THI points higher than at the stationary loggers. Furthermore, the mean daily THI was higher at the mobile cow loggers than at the stationary loggers on all experimental days. The THI in the experimental pen was 0·44 THI points lower when the experimental cow group was located inside the milking parlour. The THI measured at the mobile cow loggers was 1·63 THI points higher when the experimental cow group was located inside the milking parlour. However, there was no significant difference for all climate variables between primiparous and multiparous cows. These results indicate, there is a wide range of climate conditions inside a dairy barn and especially areas with a great distance to a fresh air supply have an increased risk for the occurrence of heat stress conditions. Furthermore, the heat stress conditions are even higher at cow level and cows not only influence their climatic environment, but also generate microclimates within different locations inside the barn. Therefore climate conditions should be obtained at cow level to evaluate the heat stress conditions that dairy cows are actually exposed to.

  8. EVALUATION OF PERCEIVED QUALITY OF THE WEBSITE OF AN ONLINE BOOKSTORE: AN EMPIRICAL APPLICATION OF THE BARNES AND VIDGEN MODEL

    Directory of Open Access Journals (Sweden)

    Ueliton da Costa Leonidio

    2011-05-01

    Full Text Available This paper’s objective is to evaluate the perceived quality of the Website of an online bookstore using the Barnes and Vidgen Model. Implemented over the Internet, this empirical research collected data on the perceived quality of the Website, used to sell products and online services. The questionnaire used to gather the data was answered by a convenience sample of 213 respondents. The importance of quality attributes and the dimension of perceived quality were investigated. The results indicate that the three dimensions named Reliability, Usability and Information were the most noticeable.

  9. SNTP program reactor design

    Science.gov (United States)

    Walton, Lewis A.; Sapyta, Joseph J.

    1993-06-01

    The Space Nuclear Thermal Propulsion (SNTP) program is evaluating the feasibility of a particle bed reactor for a high-performance nuclear thermal rocket engine. Reactors operating between 500 MW and 2,000 MW will produce engine thrusts ranging from 20,000 pounds to 80,000 pounds. The optimum reactor arrangement depends on the power level desired and the intended application. The key components of the reactor have been developed and are being tested. Flow-to-power matching considerations dominate the thermal-hydraulic design of the reactor. Optimal propellant management during decay heat cooling requires a three-pronged approach. Adequate computational methods exist to perform the neutronics analysis of the reactor core. These methods have been benchmarked to critical experiment data.

  10. Fast Spectrum Reactors

    CERN Document Server

    Todd, Donald; Tsvetkov, Pavel

    2012-01-01

    Fast Spectrum Reactors presents a detailed overview of world-wide technology contributing to the development of fast spectrum reactors. With a unique focus on the capabilities of fast spectrum reactors to address nuclear waste transmutation issues, in addition to the well-known capabilities of breeding new fuel, this volume describes how fast spectrum reactors contribute to the wide application of nuclear power systems to serve the global nuclear renaissance while minimizing nuclear proliferation concerns. Readers will find an introduction to the sustainable development of nuclear energy and the role of fast reactors, in addition to an economic analysis of nuclear reactors. A section devoted to neutronics offers the current trends in nuclear design, such as performance parameters and the optimization of advanced power systems. The latest findings on fuel management, partitioning and transmutation include the physics, efficiency and strategies of transmutation, homogeneous and heterogeneous recycling, in addit...

  11. Hybrid reactors. [Fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Moir, R.W.

    1980-09-09

    The rationale for hybrid fusion-fission reactors is the production of fissile fuel for fission reactors. A new class of reactor, the fission-suppressed hybrid promises unusually good safety features as well as the ability to support 25 light-water reactors of the same nuclear power rating, or even more high-conversion-ratio reactors such as the heavy-water type. One 4000-MW nuclear hybrid can produce 7200 kg of /sup 233/U per year. To obtain good economics, injector efficiency times plasma gain (eta/sub i/Q) should be greater than 2, the wall load should be greater than 1 MW.m/sup -2/, and the hybrid should cost less than 6 times the cost of a light-water reactor. Introduction rates for the fission-suppressed hybrid are usually rapid.

  12. The effects of apparatus design and test procedure on learning and memory performance of C57BL/6J mice on the Barnes maze.

    Science.gov (United States)

    O'Leary, Timothy P; Brown, Richard E

    2012-01-30

    The Barnes maze is a visuo-spatial learning and memory test originally designed for use with rats, and later adapted for use with mice. The Barnes maze design and test procedure vary across studies using mice, but the effects of variation in Barnes maze design and test procedure on learning and memory in mice have not yet been investigated. Therefore the present experiment investigates whether test procedures, such as the number of habituation trials and parameters of the probe trial (correct zone size and trial length) influence learning and memory performance on three Barnes maze designs that differed in size and the presence of a wall with intra-maze visual cues. Performance was compared across the three mazes to determine how apparatus design influences visuo-spatial cue use. The number of habituation trials and parameters of the probe trial had small effects on learning and memory performance. Apparatus design, had little effect on acquisition performance but had a significant effect on memory performance. Mice on a maze with a small diameter, external wall and intra-maze visual cues had very poor visuo-spatial memory relative to mice tested on small and large diameter mazes without a wall or intra-maze visual cues. Assessment of visuo-spatial cue use indicated that mice do not rely on visuo-spatial cues to locate the escape hole on the small-diameter maze with a wall and intra-maze visual cues, but show reliable visuo-spatial cue use on small or large diameter mazes with no wall. These results indicate that apparatus design influences search strategy use and memory performance on the Barnes maze, and that including a wall around the edge of the Barnes maze decreases visuo-spatial cue use.

  13. Effect of Applying Surplus Heat Sharing in Bulk Curing Barn%密集烤房余热共享应用效果研究

    Institute of Scientific and Technical Information of China (English)

    张丽英; 谢帮金; 杨启冰; 刘勇; 李立新; 齐飞

    2014-01-01

    通过比较余热共享密集烤房与无余热共享密集烤房在烘烤过程中能耗和鲜干比值的变化,研究了余热共享密集烤房的应用效果。结果表明:余热共享密集烤房的耗煤量、耗电量和鲜干比值均优于无余热共享密集烤房,有效地降低了烘烤成本。密集烤房通过余热共享,可以降低顶层烟叶烘烤后的含青度,提高顶层烟叶烘烤质量。%The effect of applying surplus heat sharing in bulk curing barn was studied by comparing the variation of energy consumption and ratio of dry weight to fresh weight in flue-curing process between bulk curing barn with surplus heat sharing and normal bulk curing barn. The results showed that in comparison normal bulk curing barn, the coal consumption, the power consumption and the ratio of dry weight to fresh weight of bulk curing barn with surplus heat sharing were all relatively better, thus reducing the curing cost effectively. Through surplus heat sharing, the bulk curing barn can reduce the green degree of top layer tobacco leaves after curing, thus improving the curing quality of top layer tobacco leaves.

  14. Multi purpose research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Raina, V.K. [Research Reactor Design and Projects Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)]. E-mail: vkrain@magnum.barc.ernet.in; Sasidharan, K. [Research Reactor Design and Projects Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Sengupta, Samiran [Research Reactor Design and Projects Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Singh, Tej [Research Reactor Services Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2006-04-15

    At present Dhruva and Cirus reactors provide the majority of research reactor based facilities to cater to the various needs of a vast pool of researchers in the field of material sciences, physics, chemistry, bio sciences, research and development work for nuclear power plants and production of radio isotopes. With a view to further consolidate and expand the scope of research and development in nuclear and allied sciences, a new 20 MWt multi purpose research reactor is being designed. This paper describes some of the design features and safety aspects of this reactor.

  15. INVAP's Research Reactor Designs

    Directory of Open Access Journals (Sweden)

    Eduardo Villarino

    2011-01-01

    Full Text Available INVAP, an Argentine company founded more than three decades ago, is today recognized as one of the leaders within the research reactor industry. INVAP has participated in several projects covering a wide range of facilities, designed in accordance with the requirements of our different clients. For complying with these requirements, INVAP developed special skills and capabilities to deal with different fuel assemblies, different core cooling systems, and different reactor layouts. This paper summarizes the general features and utilization of several INVAP research reactor designs, from subcritical and critical assemblies to high-power reactors.

  16. LMFBR type reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kanbe, Mitsuru

    1997-04-04

    An LMFBR type reactor comprises a plurality of reactor cores in a reactor container. Namely, a plurality of pot containing vessels are disposed in the reactor vessel and a plurality of reactor cores are formed in a state where an integrated-type fuel assembly is each inserted to a pot, and a coolant pipeline is connected to each of the pot containing-vessel to cool the reactor core respectively. When fuels are exchanged, the integrated-type fuel assembly is taken out together with the pot from the reactor vessel in a state where the integrated-type fuel assembly is immersed in the coolants in the pot as it is. Accordingly, coolants are supplied to each of the pot containing-vessel connected with the coolant pipeline and circulate while cooling the integrated-type fuel assembly for every pot. Then, when the fuels are exchanged, the integrated type fuel assembly is taken out to the outside of the reactor together with the pot by taking up the pot from the pot-containing vessel. Then, neutron economy is improved to thereby improve reactor power and the breeding ratio. (N.H.)

  17. Final report : results of the 2006-2007 investigation of potential contamination at the former CCC/USDA facility in Barnes, Kansas.

    Energy Technology Data Exchange (ETDEWEB)

    LaFreniere, L. M.; Environmental Science Division

    2008-08-28

    The 2006-2007 investigation of carbon tetrachloride and chloroform contamination at Barnes, Kansas, was conducted at the request of the Kansas Department of Health and Environment (KDHE). The Environmental Science Division of Argonne National Laboratory implemented the investigation on behalf of the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA). The overall goal of the investigation was to establish criteria for monitoring leading to potential site reclassification. The investigation objectives were to (1) determine the hydraulic gradient near the former CCC/USDA facility, (2) delineate the downgradient carbon tetrachloride plume, and (3) design and implement an expanded monitoring network at Barnes (Argonne 2006a).

  18. Foraging at the edge of the world: low-altitude, high-speed manoeuvering in barn swallows.

    Science.gov (United States)

    Warrick, Douglas R; Hedrick, Tyson L; Biewener, Andrew A; Crandell, Kristen E; Tobalske, Bret W

    2016-09-26

    While prior studies of swallow manoeuvering have focused on slow-speed flight and obstacle avoidance in still air, swallows survive by foraging at high speeds in windy environments. Recent advances in field-portable, high-speed video systems, coupled with precise anemometry, permit measures of high-speed aerial performance of birds in a natural state. We undertook the present study to test: (i) the manner in which barn swallows (Hirundo rustica) may exploit wind dynamics and ground effect while foraging and (ii) the relative importance of flapping versus gliding for accomplishing high-speed manoeuvers. Using multi-camera videography synchronized with wind-velocity measurements, we tracked coursing manoeuvers in pursuit of prey. Wind speed averaged 1.3-2.0 m s(-1) across the atmospheric boundary layer, exhibiting a shear gradient greater than expected, with instantaneous speeds of 0.02-6.1 m s(-1) While barn swallows tended to flap throughout turns, they exhibited reduced wingbeat frequency, relying on glides and partial bounds during maximal manoeuvers. Further, the birds capitalized on the near-earth wind speed gradient to gain kinetic and potential energy during both flapping and gliding turns; providing evidence that such behaviour is not limited to large, fixed-wing soaring seabirds and that exploitation of wind gradients by small aerial insectivores may be a significant aspect of their aeroecology.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'.

  19. a Comparison of Laser Scanning and Structure from Motion as Applied to the Great Barn at Harmondsworth, UK

    Science.gov (United States)

    Andrews, D. P.; Bedford, J.; Bryan, P. G.

    2013-07-01

    The great barn at Harmondsworth near London Heathrow airport, United Kingdom (UK), was built in 1426-7 for the Bishop of Winchester. At 58 metres long and 11.4 metres wide, it is one of the largest ever known to have been built in the UK, and the largest intact medieval timber-framed barn in England. The barn is built almost entirely of oak, although the walls rest on a low masonry sill-wall. Internally the space is divided into a central "nave" with a lower aisle to each side, and is divided along its length into 12 bays. There are three doorways on the east side. For an entirely timber-framed barn, the fabric is exceptionally well preserved. Even the external weatherboarding may be partly original. Following years of neglect, however, there are a number of on-going structural and conservation problems, so in 2011 the barn was bought by English Heritage in order to allow these needs to be addressed. English Heritage is the government agency responsible for the historic sites and buildings in the care of the state of England and is also the UK government's lead advisor on the built heritage. As one of the first steps in the conservation process the English Heritage Geospatial Imaging and Imaging & Visualisation teams undertook a four-day campaign of survey data collection. This took the form of laser scanning of the interior and exterior of the barn plus the acquisition of photography of the exterior elevations to be used with structure from motion (SFM) software. A comparison of the results of these complimentary yet potentially competing technologies will be given, as well as an evaluation of when they can be successfully used together. This paper will describe the procedures and problems involved with collecting the survey data and its subsequent analysis. The laser scanning was undertaken using a FARO Focus 3D phase based instrument. Approximately 60 scans were acquired in order to provide as comprehensive as possible coverage given the site circumstances. A

  20. Sex-linked inheritance, genetic correlations and sexual dimorphism in three melanin-based colour traits in the barn owl.

    Science.gov (United States)

    Roulin, A; Jensen, H

    2015-03-01

    Theory states that genes on the sex chromosomes have stronger effects on sexual dimorphism than genes on the autosomes. Although empirical data are not necessarily consistent with this theory, this situation may prevail because the relative role of sex-linked and autosomally inherited genes on sexual dimorphism has rarely been evaluated. We estimated the quantitative genetics of three sexually dimorphic melanin-based traits in the barn owl (Tyto alba), in which females are on average darker reddish pheomelanic and display more and larger black eumelanic feather spots than males. The plumage traits with higher sex-linked inheritance showed lower heritability and genetic correlations, but contrary to prediction, these traits showed less pronounced sexual dimorphism. Strong offspring sexual dimorphism primarily resulted from daughters not expressing malelike melanin-based traits and from sons expressing femalelike traits to similar degrees as their sisters. We conclude that in the barn owl, polymorphism at autosomal genes rather than at sex-linked genes generate variation in sexual dimorphism in melanin-based traits.

  1. Muscular Arrangement and Muscle Attachment Sites in the Cervical Region of the American Barn Owl (Tyto furcata pratincola).

    Science.gov (United States)

    Boumans, Mark L L M; Krings, Markus; Wagner, Hermann

    2015-01-01

    Owls have the largest head rotation capability amongst vertebrates. Anatomical knowledge of the cervical region is needed to understand the mechanics of these extreme head movements. While data on the morphology of the cervical vertebrae of the barn owl have been provided, this study is aimed to provide an extensive description of the muscle arrangement and the attachment sites of the muscles on the owl's head-neck region. The major cervical muscles were identified by gross dissection of cadavers of the American barn owl (Tyto furcata pratincola), and their origin, courses, and insertion were traced. In the head-neck region nine superficial larger cervical muscles of the craniocervical, dorsal and ventral subsystems were selected for analysis, and the muscle attachment sites were illustrated in digital models of the skull and cervical vertebrae of the same species as well as visualised in a two-dimensional sketch. In addition, fibre orientation and lengths of the muscles and the nature (fleshy or tendinous) of the attachment sites were determined. Myological data from this study were combined with osteological data of the same species. This improved the anatomical description of the cervical region of this species. The myological description provided in this study is to our best knowledge the most detailed documentation of the cervical muscles in a strigiform species presented so far. Our results show useful information for researchers in the field of functional anatomy, biomechanical modelling and for evolutionary and comparative studies.

  2. Muscular Arrangement and Muscle Attachment Sites in the Cervical Region of the American Barn Owl (Tyto furcata pratincola.

    Directory of Open Access Journals (Sweden)

    Mark L L M Boumans

    Full Text Available Owls have the largest head rotation capability amongst vertebrates. Anatomical knowledge of the cervical region is needed to understand the mechanics of these extreme head movements. While data on the morphology of the cervical vertebrae of the barn owl have been provided, this study is aimed to provide an extensive description of the muscle arrangement and the attachment sites of the muscles on the owl's head-neck region. The major cervical muscles were identified by gross dissection of cadavers of the American barn owl (Tyto furcata pratincola, and their origin, courses, and insertion were traced. In the head-neck region nine superficial larger cervical muscles of the craniocervical, dorsal and ventral subsystems were selected for analysis, and the muscle attachment sites were illustrated in digital models of the skull and cervical vertebrae of the same species as well as visualised in a two-dimensional sketch. In addition, fibre orientation and lengths of the muscles and the nature (fleshy or tendinous of the attachment sites were determined. Myological data from this study were combined with osteological data of the same species. This improved the anatomical description of the cervical region of this species. The myological description provided in this study is to our best knowledge the most detailed documentation of the cervical muscles in a strigiform species presented so far. Our results show useful information for researchers in the field of functional anatomy, biomechanical modelling and for evolutionary and comparative studies.

  3. Light water reactor program

    Energy Technology Data Exchange (ETDEWEB)

    Franks, S.M.

    1994-12-31

    The US Department of Energy`s Light Water Reactor Program is outlined. The scope of the program consists of: design certification of evolutionary plants; design, development, and design certification of simplified passive plants; first-of-a-kind engineering to achieve commercial standardization; plant lifetime improvement; and advanced reactor severe accident program. These program activities of the Office of Nuclear Energy are discussed.

  4. Space Nuclear Reactor Engineering

    Energy Technology Data Exchange (ETDEWEB)

    Poston, David Irvin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-06

    We needed to find a space reactor concept that could be attractive to NASA for flight and proven with a rapid turnaround, low-cost nuclear test. Heat-pipe-cooled reactors coupled to Stirling engines long identified as the easiest path to near-term, low-cost concept.

  5. Reactor Materials Research

    Energy Technology Data Exchange (ETDEWEB)

    Van Walle, E

    2001-04-01

    The activities of the Reactor Materials Research Department of the Belgian Nuclear Research Centre SCK-CEN in 2000 are summarised. The programmes within the department are focussed on studies concerning (1) fusion, in particular mechanical testing; (2) Irradiation Assisted Stress Corrosion Cracking (IASCC); (3) nuclear fuel; and (4) Reactor Pressure Vessel Steel (RPVS)

  6. Nuclear reactor design

    CERN Document Server

    2014-01-01

    This book focuses on core design and methods for design and analysis. It is based on advances made in nuclear power utilization and computational methods over the past 40 years, covering core design of boiling water reactors and pressurized water reactors, as well as fast reactors and high-temperature gas-cooled reactors. The objectives of this book are to help graduate and advanced undergraduate students to understand core design and analysis, and to serve as a background reference for engineers actively working in light water reactors. Methodologies for core design and analysis, together with physical descriptions, are emphasized. The book also covers coupled thermal hydraulic core calculations, plant dynamics, and safety analysis, allowing readers to understand core design in relation to plant control and safety.

  7. Status of French reactors

    Energy Technology Data Exchange (ETDEWEB)

    Ballagny, A. [Commissariat a l`Energie Atomique, Saclay (France)

    1997-08-01

    The status of French reactors is reviewed. The ORPHEE and RHF reactors can not be operated with a LEU fuel which would be limited to 4.8 g U/cm{sup 3}. The OSIRIS reactor has already been converted to LEU. It will use U{sub 3}Si{sub 2} as soon as its present stock of UO{sub 2} fuel is used up, at the end of 1994. The decision to close down the SILOE reactor in the near future is not propitious for the start of a conversion process. The REX 2000 reactor, which is expected to be commissioned in 2005, will use LEU (except if the fast neutrons core option is selected). Concerning the end of the HEU fuel cycle, the best option is reprocessing followed by conversion of the reprocessed uranium to LEU.

  8. "Det är ett vanligt barn, även om det är lite speciellt" : Några förskollärares syn på begreppet barn i behov av särskilt stöd

    OpenAIRE

    Vuento, Noora; Waldenström, Inger

    2013-01-01

    Syftet med denna studie var att undersöka hur några förskollärare ser på begreppet barn i behov av särskilt stöd och vilka barn som omfattas av begreppet enligt dem. De forskningsfrågor vi ställde var hur förskollärare definierar begreppet barn i behov av särskilt stöd, hur förskollärare gör bedömningen av vilka barn som är i behov av särskilt stöd samt hur förskollärare tolkar förskolans uppdrag när det gäller barn i behov av särskilt stöd. För att undersöka dessa frågor använde vi oss av kv...

  9. Dairy barns and roll-over protection on farm tractors: work environment impacts on the adoption of roll-over protective structures.

    Science.gov (United States)

    Kelsey, T W; Dennis, J W; Jenkins, P L

    1994-04-01

    A mailed survey of one group of dairy farmers supports the informal perception that roll-over protective structure (ROPS)-equipped tractors are considered unusable for in-barn tasks. This attitude must be addressed in order to achieve greater use of safety equipment.

  10. Study of $ \\bar{p} $ and $ \\bar{n} $ annihilations at LEAR with OBELIX, a large acceptance and high resolution detector based on the Open Axial Field Spectrometer

    CERN Multimedia

    2002-01-01

    % PS201 Study of $\\bar{p}$ and $\\bar{n}$ annihilations at LEAR with OBELIX, a large acceptance and high resolution detector based on the Open Axial Field Spectrometer \\\\ \\\\OBELIX is designed to study exclusive final states of antiproton and antineutron annihilations at low energies with protons and nuclei. \\\\ \\\\The physics motivations of the experiment are:\\\\ \\\\\\begin{itemize} \\item (gg, ggg), hybrids ($ q \\bar{q} g $), multiquarks ($ q q \\bar{q} \\bar{q} $) and light mesons ($ q \\bar{q} $) produced in $ N \\bar{N} $ annihilations and study of their spectroscopy and decays. Also broad structures will be searched for by comparing identical decay modes in exclusive final states of the same type occuring from initial states with different angular momentum or isospin. \\item Study of the dynamics of $ N \\bar{N} $ interactions and of the dependence of the final and intermediate resonant states of annihilation upon the quantum numbers of the initial $ N \\bar{N} $ state (angular momentum: S and P-wave in $\\bar{p}p $ at...

  11. Tests of the Aversive Summation Hypothesis in Rats: Effects of Restraint Stress on Consummatory Successive Negative Contrast and Extinction in the Barnes Maze

    Science.gov (United States)

    Ortega, Leonardo A.; Prado-Rivera, Mayerli A.; Cardenas-Poveda, D. Carolina; McLinden, Kristina A.; Glueck, Amanda C.; Gutierrez, German; Lamprea, Marisol R.; Papini, Mauricio R.

    2013-01-01

    The present research explored the effects of restraint stress on two situations involving incentive downshift: consummatory successive negative contrast (cSNC) and extinction of escape behavior in the Barnes maze. First, Experiment 1 confirmed that the restraint stress procedure used in these experiments increased levels of circulating…

  12. Slurry reactor design studies

    Energy Technology Data Exchange (ETDEWEB)

    Fox, J.M.; Degen, B.D.; Cady, G.; Deslate, F.D.; Summers, R.L. (Bechtel Group, Inc., San Francisco, CA (USA)); Akgerman, A. (Texas A and M Univ., College Station, TX (USA)); Smith, J.M. (California Univ., Davis, CA (USA))

    1990-06-01

    The objective of these studies was to perform a realistic evaluation of the relative costs of tublar-fixed-bed and slurry reactors for methanol, mixed alcohols and Fischer-Tropsch syntheses under conditions where they would realistically be expected to operate. The slurry Fischer-Tropsch reactor was, therefore, operated at low H{sub 2}/CO ratio on gas directly from a Shell gasifier. The fixed-bed reactor was operated on 2.0 H{sub 2}/CO ratio gas after adjustment by shift and CO{sub 2} removal. Every attempt was made to give each reactor the benefit of its optimum design condition and correlations were developed to extend the models beyond the range of the experimental pilot plant data. For the methanol design, comparisons were made for a recycle plant with high methanol yield, this being the standard design condition. It is recognized that this is not necessarily the optimum application for the slurry reactor, which is being proposed for a once-through operation, coproducing methanol and power. Consideration is also given to the applicability of the slurry reactor to mixed alcohols, based on conditions provided by Lurgi for an Octamix{trademark} plant using their standard tubular-fixed reactor technology. 7 figs., 26 tabs.

  13. Gas cooled fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1972-06-01

    Although most of the development work on fast breeder reactors has been devoted to the use of liquid metal cooling, interest has been expressed for a number of years in alternative breeder concepts using other coolants. One of a number of concepts in which interest has been retained is the Gas-Cooled Fast Reactor (GCFR). As presently envisioned, it would operate on the uranium-plutonium mixed oxide fuel cycle, similar to that used in the Liquid Metal Fast Breeder Reactor (LMFBR), and would use helium gas as the coolant.

  14. Microfluidic electrochemical reactors

    Science.gov (United States)

    Nuzzo, Ralph G [Champaign, IL; Mitrovski, Svetlana M [Urbana, IL

    2011-03-22

    A microfluidic electrochemical reactor includes an electrode and one or more microfluidic channels on the electrode, where the microfluidic channels are covered with a membrane containing a gas permeable polymer. The distance between the electrode and the membrane is less than 500 micrometers. The microfluidic electrochemical reactor can provide for increased reaction rates in electrochemical reactions using a gaseous reactant, as compared to conventional electrochemical cells. Microfluidic electrochemical reactors can be incorporated into devices for applications such as fuel cells, electrochemical analysis, microfluidic actuation, pH gradient formation.

  15. Fast Breeder Reactor studies

    Energy Technology Data Exchange (ETDEWEB)

    Till, C.E.; Chang, Y.I.; Kittel, J.H.; Fauske, H.K.; Lineberry, M.J.; Stevenson, M.G.; Amundson, P.I.; Dance, K.D.

    1980-07-01

    This report is a compilation of Fast Breeder Reactor (FBR) resource documents prepared to provide the technical basis for the US contribution to the International Nuclear Fuel Cycle Evaluation. The eight separate parts deal with the alternative fast breeder reactor fuel cycles in terms of energy demand, resource base, technical potential and current status, safety, proliferation resistance, deployment, and nuclear safeguards. An Annex compares the cost of decommissioning light-water and fast breeder reactors. Separate abstracts are included for each of the parts.

  16. Continuous measurement of reticuloruminal pH values in dairy cows during the transition period from barn to pasture feeding using an indwelling wireless data transmitting unit.

    Science.gov (United States)

    Gasteiner, J; Horn, M; Steinwidder, A

    2015-04-01

    This study was performed to investigate the effect of the transition from barn feeding to pasture on the pattern of reticuloruminal pH values in 8 multiparous dairy cows. A indwelling wireless data transmitting system for pH measurement was given to 8 multiparous cows orally. Reticuloruminal pH values were measured every 600 s over a period of 42 days. After 7 days of barn feeding (period 1), all of the animals were pastured with increasing grazing times from 2 to 7 h/day over 7 days (period 2). From day 15 to day 21 (period 3), the cows spent 7 h/day on pasture. Beginning on day 22, the animals had 20 h/day access to pasture (day and night grazing). To study reticuloruminal adaptation to pasture feeding, the phase of day and night grazing was subdivided into another 3 weekly periods (periods 4-6). Despite a mild transition period from barn feeding to pasture, significant effects on reticuloruminal pH values were observed. During barn feeding, the mean reticuloruminal pH value for all of the cows was 6.44 ± 0.14, and the pH values decreased significantly (p pH values increased again (pH 6.25 ± 0.22; pH 6.31 ± 0.17; pH 6.37 ± 0.16). Our results showed that the animals had significantly lowered reticuloruminal pH during the periods of feed transition from barn to pasture feeding. Despite these significant changes, the decrease was not harmful, as indicated by data of feed intake and milk production.

  17. Reactor BR2. Introduction

    Energy Technology Data Exchange (ETDEWEB)

    Gubel, P

    2001-04-01

    The BR2 is a materials testing reactor and is still one of SCK-CEN's important nuclear facilities. After an extensive refurbishment to compensate for the ageing of the installation, the reactor was restarted in April 1997. During the last three years, the availability of the installation was maintained at an average level of 97.6 percent. In the year 2000, the reactor was operated for a total of 104 days at a mean power of 56 MW. In 2000, most irradiation experiments were performed in the CALLISTO PWR loop. The report describes irradiations achieved or under preparation in 2000, including the development of advanced facilities and concept studies for new programmes. An overview of the scientific irradiation programmes as well as of the R and D programme of the BR2 reactor in 2000 is given.

  18. Reactor Neutrino Spectra

    CERN Document Server

    Hayes, A C

    2016-01-01

    We present a review of the antineutrino spectra emitted from reactors. Knowledge of these and their associated uncertainties are crucial for neutrino oscillation studies. The spectra used to-date have been determined by either conversion of measured electron spectra to antineutrino spectra or by summing over all of the thousands of transitions that makeup the spectra using modern databases as input. The uncertainties in the subdominant corrections to beta-decay plague both methods, and we provide estimates of these uncertainties. Improving on current knowledge of the antineutrino spectra from reactors will require new experiments. Such experiments would also address the so-called reactor neutrino anomaly and the possible origin of the shoulder observed in the antineutrino spectra measured in recent high-statistics reactor neutrino experiments.

  19. New reactor type proposed

    CERN Multimedia

    2003-01-01

    "Russian scientists at the Research Institute of Nuclear Power Engineering in Moscow are hoping to develop a new reactor that will use lead and bismuth as fuel instead of uranium and plutonium" (1/2 page).

  20. Sex-related effects of an immune challenge on growth and begging behavior of barn swallow nestlings.

    Science.gov (United States)

    Romano, Andrea; Rubolini, Diego; Caprioli, Manuela; Boncoraglio, Giuseppe; Ambrosini, Roberto; Saino, Nicola

    2011-01-01

    Parent-offspring conflicts lead the offspring to evolve reliable signals of individual quality, including parasite burden, which may allow parents to adaptively modulate investment in the progeny. Sex-related variation in offspring reproductive value, however, may entail differential investment in sons and daughters. Here, we experimentally manipulated offspring condition in the barn swallow (Hirundo rustica) by subjecting nestlings to an immune challenge (injection with bacterial lipopolysaccharide, LPS) that simulates a bacterial infection, and assessed the effects on growth, feather quality, expression of morphological (gape coloration) and behavioral (posture) begging displays involved in parent-offspring communication, as well as on food allocation by parents. Compared to sham-injected controls, LPS-treated chicks suffered a depression of body mass and a reduction of palate color saturation. In addition, LPS treatment resulted in lower feather quality, with an increase in the occurrence of fault bars on wing feathers. The color of beak flanges, feather growth and the intensity of postural begging were affected by LPS treatment only in females, suggesting that chicks of either sex are differently susceptible to the immune challenge. However, irrespective of the effects of LPS, parents equally allocated food among control and challenged offspring both under normal food provisioning and after a short period of food deprivation of the chicks. These results indicate that bacterial infection and the associated immune response entail different costs to offspring of either sex, but a decrease in nestling conditions does not affect parental care allocation, possibly because the barn swallow adopts a brood-survival strategy. Finally, we showed that physiological stress induced by pathogens impairs plumage quality, a previously neglected major negative impact of bacterial infection which could severely affect fitness, particularly among long-distance migratory birds.

  1. Helias reactor studies

    Energy Technology Data Exchange (ETDEWEB)

    Beidler, C.D. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Grieger, G. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Harmeyer, E. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Kisslinger, J. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Karulin, N. [Nuclear Fusion Institute, Moscow (Russian Federation); Maurer, W. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany); Nuehrenberg, J. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Rau, F. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Sapper, J. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Wobig, H. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany)

    1995-10-01

    The present status of Helias reactor studies is characterised by the identification and investigation of specific issues which result from the particular properties of this type of stellarator. On the technical side these are issues related to the coil system, while physics studies have concentrated on confinement, alpha-particle behaviour and ignition conditions. The usual assumptions have been made in those fields which are common to all toroidal fusion reactors: blanket and shield, refuelling and exhaust, safety and economic aspects. For blanket and shield sufficient space has been provided, a detailed concept will be developed in future. To date more emphasis has been placed on scoping and parameter studies as opposed to fixing a specific set of parameters and providing a detailed point study. One result of the Helias reactor studies is that physical dimensions are on the same order as those of tokamak reactors. However, it should be noticed that this comparison is difficult in view of the large spectrum of tokamak reactors ranging from a small reactor like Aries, to a large device such as SEAFP. The notion that the large aspect ratio of 10 or more in Helias configurations also leads to large reactors is misleading, since the large major radius of 22 m is compensated by the average plasma radius of 1.8 m and the average coil radius of 5 m. The plasma volume of 1400 m{sup 3} is about the same as the ITER reactor and the magnetic energy of the coil system is about the same or even slightly smaller than envisaged in ITER. (orig.)

  2. Future Reactor Experiments

    OpenAIRE

    He, Miao

    2013-01-01

    The measurement of the neutrino mixing angle $\\theta_{13}$ opens a gateway for the next generation experiments to measure the neutrino mass hierarchy and the leptonic CP-violating phase. Future reactor experiments will focus on mass hierarchy determination and the precision measurement of mixing parameters. Mass hierarchy can be determined from the disappearance of reactor electron antineutrinos based on the interference effect of two separated oscillation modes. Relative and absolute measure...

  3. Reactor Neutrino Experiments

    OpenAIRE

    Cao, Jun

    2007-01-01

    Precisely measuring $\\theta_{13}$ is one of the highest priority in neutrino oscillation study. Reactor experiments can cleanly determine $\\theta_{13}$. Past reactor neutrino experiments are reviewed and status of next precision $\\theta_{13}$ experiments are presented. Daya Bay is designed to measure $\\sin^22\\theta_{13}$ to better than 0.01 and Double Chooz and RENO are designed to measure it to 0.02-0.03. All are heading to full operation in 2010. Recent improvements in neutrino moment measu...

  4. Department of Reactor Technology

    DEFF Research Database (Denmark)

    Risø National Laboratory, Roskilde

    The general development of the Department of Reactor Technology at Risø during 1981 is presented, and the activities within the major subject fields are described in some detail. Lists of staff, publications, and computer programs are included.......The general development of the Department of Reactor Technology at Risø during 1981 is presented, and the activities within the major subject fields are described in some detail. Lists of staff, publications, and computer programs are included....

  5. Moon base reactor system

    Science.gov (United States)

    Chavez, H.; Flores, J.; Nguyen, M.; Carsen, K.

    1989-01-01

    The objective of our reactor design is to supply a lunar-based research facility with 20 MW(e). The fundamental layout of this lunar-based system includes the reactor, power conversion devices, and a radiator. The additional aim of this reactor is a longevity of 12 to 15 years. The reactor is a liquid metal fast breeder that has a breeding ratio very close to 1.0. The geometry of the core is cylindrical. The metallic fuel rods are of beryllium oxide enriched with varying degrees of uranium, with a beryllium core reflector. The liquid metal coolant chosen was natural lithium. After the liquid metal coolant leaves the reactor, it goes directly into the power conversion devices. The power conversion devices are Stirling engines. The heated coolant acts as a hot reservoir to the device. It then enters the radiator to be cooled and reenters the Stirling engine acting as a cold reservoir. The engines' operating fluid is helium, a highly conductive gas. These Stirling engines are hermetically sealed. Although natural lithium produces a lower breeding ratio, it does have a larger temperature range than sodium. It is also corrosive to steel. This is why the container material must be carefully chosen. One option is to use an expensive alloy of cerbium and zirconium. The radiator must be made of a highly conductive material whose melting point temperature is not exceeded in the reactor and whose structural strength can withstand meteor showers.

  6. Upper limit on the cross section for reactor antineutrinos changing 22Na decay rates

    CERN Document Server

    de Meijer, R J

    2014-01-01

    In this paper we present results of a long-term observation of the decay of 22Na in the presence of a nuclear fission reactor. The measurements were made outside the containment wall of and underneath the Koeberg nuclear power plant near Cape Town, South Africa. Antineutrino fluxes ranged from ~5*10^11 to 1.6*10^13 cm^-2 s^-1 during this period. We show that the coincidence summing technique provides a sensitive tool to measure a change in the total decay constant as well as the branching ratio between EC and beta+ decay of 22Na to the first excited state in 22Ne. We observe a relative change in count rate between reactor-ON and reactor-OFF equal to (-0.51+/-0.11)*10^-4. After evaluating possible systematic uncertainties we conclude that the effect is either due to a hidden instrumental cause or due to an interaction between antineutrinos and the 22Na nucleus. An upper limit of ~0.03 barn has been deduced for observing any change in the decay rate of 22Na due to antineutrino interactions.

  7. Reactor Safety Planning for Prometheus Project, for Naval Reactors Information

    Energy Technology Data Exchange (ETDEWEB)

    P. Delmolino

    2005-05-06

    The purpose of this letter is to submit to Naval Reactors the initial plan for the Prometheus project Reactor Safety work. The Prometheus project is currently developing plans for cold physics experiments and reactor prototype tests. These tests and facilities may require safety analysis and siting support. In addition to the ground facilities, the flight reactor units will require unique analyses to evaluate the risk to the public from normal operations and credible accident conditions. This letter outlines major safety documents that will be submitted with estimated deliverable dates. Included in this planning is the reactor servicing documentation and shipping analysis that will be submitted to Naval Reactors.

  8. REACTOR GROUT THERMAL PROPERTIES

    Energy Technology Data Exchange (ETDEWEB)

    Steimke, J.; Qureshi, Z.; Restivo, M.; Guerrero, H.

    2011-01-28

    Savannah River Site has five dormant nuclear production reactors. Long term disposition will require filling some reactor buildings with grout up to ground level. Portland cement based grout will be used to fill the buildings with the exception of some reactor tanks. Some reactor tanks contain significant quantities of aluminum which could react with Portland cement based grout to form hydrogen. Hydrogen production is a safety concern and gas generation could also compromise the structural integrity of the grout pour. Therefore, it was necessary to develop a non-Portland cement grout to fill reactors that contain significant quantities of aluminum. Grouts generate heat when they set, so the potential exists for large temperature increases in a large pour, which could compromise the integrity of the pour. The primary purpose of the testing reported here was to measure heat of hydration, specific heat, thermal conductivity and density of various reactor grouts under consideration so that these properties could be used to model transient heat transfer for different pouring strategies. A secondary purpose was to make qualitative judgments of grout pourability and hardened strength. Some reactor grout formulations were unacceptable because they generated too much heat, or started setting too fast, or required too long to harden or were too weak. The formulation called 102H had the best combination of characteristics. It is a Calcium Alumino-Sulfate grout that contains Ciment Fondu (calcium aluminate cement), Plaster of Paris (calcium sulfate hemihydrate), sand, Class F fly ash, boric acid and small quantities of additives. This composition afforded about ten hours of working time. Heat release began at 12 hours and was complete by 24 hours. The adiabatic temperature rise was 54 C which was within specification. The final product was hard and displayed no visible segregation. The density and maximum particle size were within specification.

  9. Scaleable, High Efficiency Microchannel Sabatier Reactor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A Microchannel Sabatier Reactor System (MSRS) consisting of cross connected arrays of isothermal or graded temperature reactors is proposed. The reactor array...

  10. LMFBR type reactor

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Takeshi; Iida, Masaaki; Moriki, Yasuyuki

    1994-10-18

    A reactor core is divided into a plurality of coolants flowrate regions, and electromagnetic pumps exclusively used for each of the flowrate regions are disposed to distribute coolants flowrates in the reactor core. Further, the flowrate of each of the electromagnetic pumps is automatically controlled depending on signals from a temperature detector disposed at the exit of the reactor core, so that the flowrate of the region can be controlled optimally depending on the burning of reactor core fuels. Then, the electromagnetic pumps disposed for every divided region are controlled respectively, so that the coolants flowrate distribution suitable to each of the regions can be attained. Margin for fuel design is decreased, fuels are used effectively, as well as an operation efficiency can be improved. Moreover, since the electromagnetic pump has less flow resistance compared with a mechanical type pump, and flow resistance of the reactor core flowrate control mechanism is eliminated, greater circulating flowrate can be ensured after occurrence of accident in a natural convection using a buoyancy of coolants utilizable for after-heat removal as a driving force. (N.H.).

  11. Reactor Structural Materials: Reactor Pressure Vessel Steels

    Energy Technology Data Exchange (ETDEWEB)

    Chaouadi, R

    2000-07-01

    The objectives of SCK-CEN's R and D programme on Rector Pressure Vessel (RPV) Steels are:(1) to complete the fracture toughness data bank of various reactor pressure vessel steels by using precracked Charpy specimens that were tested statically as well as dynamically; (2) to implement the enhanced surveillance approach in a user-friendly software; (3) to improve the existing reconstitution technology by reducing the input energy (short cycle welding) and modifying the stud geometry. Progress and achievements in 1999 are reported.

  12. Thermionic Reactor Design Studies

    Energy Technology Data Exchange (ETDEWEB)

    Schock, Alfred

    1994-08-01

    Paper presented at the 29th IECEC in Monterey, CA in August 1994. The present paper describes some of the author's conceptual designs and their rationale, and the special analytical techniques developed to analyze their (thermionic reactor) performance. The basic designs, first published in 1963, are based on single-cell converters, either double-ended diodes extending over the full height of the reactor core or single-ended diodes extending over half the core height. In that respect they are similar to the thermionic fuel elements employed in the Topaz-2 reactor subsequently developed in the Soviet Union, copies of which were recently imported by the U.S. As in the Topaz-2 case, electrically heated steady-state performance tests of the converters are possible before fueling.

  13. Nuclear Rocket Engine Reactor

    CERN Document Server

    Lanin, Anatoly

    2013-01-01

    The development of a nuclear rocket engine reactor (NRER ) is presented in this book. The working capacity of an active zone NRER under mechanical and thermal load, intensive neutron fluxes, high energy generation (up to 30 MBT/l) in a working medium (hydrogen) at temperatures up to 3100 K is displayed. Design principles and bearing capacity of reactors area discussed on the basis of simulation experiments and test data of a prototype reactor. Property data of dense constructional, porous thermal insulating and fuel materials like carbide and uranium carbide compounds in the temperatures interval 300 - 3000 K are presented. Technological aspects of strength and thermal strength resistance of materials are considered. The design procedure of possible emergency processes in the NRER is developed and risks for their origination are evaluated. Prospects of the NRER development for pilotless space devices and piloted interplanetary ships are viewed.

  14. Operation of Reactor

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    3.1 Annual Report of SPR Operation Chu Shaochu Having overseen by National Nuclear Safety Administration and specialists, the reactor restarted up successfully after Safety renovation on April 16, 1996. In August 1996 the normal operation of SPR was approved by the authorities of Naitonal Nuclear Safety Administration. 1 Operation status In 1996, the reactor operated safely for 40 d and the energy released was about 137.3 MW·d. The operation status of SPR is shown in table 1. The reactor started up to higher power (power more than 1 MW) and lower power (for physics experiments) 4 times and 14 times respectively. Measurement of control rod efficiency and other measurement tasks were 2 times and 5 times respectively.

  15. An Overview of Reactor Concepts, a Survey of Reactor Designs.

    Science.gov (United States)

    1985-02-01

    Public Affairs Office and is releasaole to the National Technical Information Services (NTIS). At NTIS, it will be available to the general public...Reactors that use deu- terium (heavy water) as a coolant can use natural uranium as a fuel. The * Canadian reactor, CANDU , utilizes this concept...reactor core at the top and discharged at the Dotton while the reactor is in operation. The discharged fuel can then b inspected to see if it can De used

  16. Oscillatory flow chemical reactors

    Directory of Open Access Journals (Sweden)

    Slavnić Danijela S.

    2014-01-01

    Full Text Available Global market competition, increase in energy and other production costs, demands for high quality products and reduction of waste are forcing pharmaceutical, fine chemicals and biochemical industries, to search for radical solutions. One of the most effective ways to improve the overall production (cost reduction and better control of reactions is a transition from batch to continuous processes. However, the reactions of interests for the mentioned industry sectors are often slow, thus continuous tubular reactors would be impractically long for flow regimes which provide sufficient heat and mass transfer and narrow residence time distribution. The oscillatory flow reactors (OFR are newer type of tube reactors which can offer solution by providing continuous operation with approximately plug flow pattern, low shear stress rates and enhanced mass and heat transfer. These benefits are the result of very good mixing in OFR achieved by vortex generation. OFR consists of cylindrical tube containing equally spaced orifice baffles. Fluid oscillations are superimposed on a net (laminar flow. Eddies are generated when oscillating fluid collides with baffles and passes through orifices. Generation and propagation of vortices create uniform mixing in each reactor cavity (between baffles, providing an overall flow pattern which is close to plug flow. Oscillations can be created by direct action of a piston or a diaphragm on fluid (or alternatively on baffles. This article provides an overview of oscillatory flow reactor technology, its operating principles and basic design and scale - up characteristics. Further, the article reviews the key research findings in heat and mass transfer, shear stress, residence time distribution in OFR, presenting their advantages over the conventional reactors. Finally, relevant process intensification examples from pharmaceutical, polymer and biofuels industries are presented.

  17. Phylogenetic systematics of Barn Owl (Tyto alba (Scopoli, 1769 complex inferred from mitochondrial rDNA (16S rRNA taxonomic implication

    Directory of Open Access Journals (Sweden)

    Mansour Aliabadian

    2012-09-01

    Full Text Available The Barn owl, Tyto alba (Scopoli, 1769, occurs worldwide and shows a considerable amount of morphological and geographical variations, leading to the recognition of many subspecies throughout the world. Yet, no comprehensive study has not been done on this species. Data from mitochondrial gene (16S Ribosomal RNA (16S with 569 bp length were analyzed for 41 individuals around the world. Maximum likelihood (ML, maximum parsimony (MP and Bayesian analysis showed two distinct clades including alba clad (old world and furcata clad (new world. The amount of genetic variation within each of these clades ranged from 0.5-1.7 but variation between clades was 3.7. This data may suggest that Barn owls of the Old World may be a separate species from those of the New World.

  18. Perspectives on reactor safety

    Energy Technology Data Exchange (ETDEWEB)

    Haskin, F.E. [New Mexico Univ., Albuquerque, NM (United States). Dept. of Chemical and Nuclear Engineering; Camp, A.L. [Sandia National Labs., Albuquerque, NM (United States)

    1994-03-01

    The US Nuclear Regulatory Commission (NRC) maintains a technical training center at Chattanooga, Tennessee to provide appropriate training to both new and experienced NRC employees. This document describes a one-week course in reactor, safety concepts. The course consists of five modules: (1) historical perspective; (2) accident sequences; (3) accident progression in the reactor vessel; (4) containment characteristics and design bases; and (5) source terms and offsite consequences. The course text is accompanied by slides and videos during the actual presentation of the course.

  19. Reactor Materials Research

    Energy Technology Data Exchange (ETDEWEB)

    Van Walle, E

    2002-04-01

    The activities of SCK-CEN's Reactor Materials Research Department for 2001 are summarised. The objectives of the department are: (1) to evaluate the integrity and behaviour of structural materials used in nuclear power industry; (2) to conduct research to unravel and understand the parameters that determine the material behaviour under or after irradiation; (3) to contribute to the interpretation, the modelling of the material behaviour and to develop and assess strategies for optimum life management of nuclear power plant components. The programmes within the department are focussed on studies concerning (1) Irradiation Assisted Stress Corrosion Cracking (IASCC); (2) nuclear fuel; and (3) Reactor Pressure Vessel Steel.

  20. Phylogenetic systematics of Barn Owl (Tyto alba (Scopoli, 1769)) complex inferred from mitochondrial rDNA (16S rRNA) taxonomic implication

    OpenAIRE

    2012-01-01

    The Barn owl, Tyto alba (Scopoli, 1769), occurs worldwide and shows a considerable amount of morphological and geographical variations, leading to the recognition of many subspecies throughout the world. Yet, no comprehensive study has not been done on this species. Data from mitochondrial gene (16S Ribosomal RNA (16S)) with 569 bp length were analyzed for 41 individuals around the world. Maximum likelihood (ML), maximum parsimony (MP) and Bayesian analysis showed two distinct clades includin...

  1. Barn owl (Tyto alba predation on small mammals and its role in the control of hantavirus natural reservoirs in a periurban area in southeastern Brazil

    Directory of Open Access Journals (Sweden)

    L. Magrini

    Full Text Available The aim of this study was to inventory the species of small mammals in Uberlândia, Minas Gerais, Brazil, based on regurgitated pellets of the barn owl and to compare the frequency of rodent species in the diet and in the environment. Since in the region there is a high incidence of hantavirus infection, we also evaluate the importance of the barn owl in the control of rodents that transmit the hantavirus. Data on richness and relative abundance of rodents in the municipality were provided by the Centro de Controle de Zoonoses, from three half-yearly samplings with live traps. In total, 736 food items were found from the analysis of 214 pellets and fragments. Mammals corresponded to 86.0% of food items and were represented by one species of marsupial (Gracilinanus agilis and seven species of rodents, with Calomys tener (70.9% and Necromys lasiurus (6.7% being the most frequent. The proportion of rodent species in barn owl pellets differed from that observed in trap samplings, with Calomys expulsus, C. tener and Oligoryzomys nigripes being consumed more frequently than expected. Although restricted to a single place and based on few individuals, the present study allowed the inventory of eight species of small mammals in Uberlândia. The comparison of the relative frequencies of rodent species in the diet and in the environment indicated selectivity. The second most preyed upon species was N. lasiurus, the main hantavirus reservoir in the Cerrado biome. In this way, the barn owl might play an important role in the control of this rodent in the region, contributing to the avoidance of a higher number of cases of hantavirus infection.

  2. Reactor operation environmental information document

    Energy Technology Data Exchange (ETDEWEB)

    Haselow, J.S.; Price, V.; Stephenson, D.E.; Bledsoe, H.W.; Looney, B.B.

    1989-12-01

    The Savannah River Site (SRS) produces nuclear materials, primarily plutonium and tritium, to meet the requirements of the Department of Defense. These products have been formed in nuclear reactors that were built during 1950--1955 at the SRS. K, L, and P reactors are three of five reactors that have been used in the past to produce the nuclear materials. All three of these reactors discontinued operation in 1988. Currently, intense efforts are being extended to prepare these three reactors for restart in a manner that protects human health and the environment. To document that restarting the reactors will have minimal impacts to human health and the environment, a three-volume Reactor Operations Environmental Impact Document has been prepared. The document focuses on the impacts of restarting the K, L, and P reactors on both the SRS and surrounding areas. This volume discusses the geology, seismology, and subsurface hydrology. 195 refs., 101 figs., 16 tabs.

  3. High Flux Isotope Reactor (HFIR)

    Data.gov (United States)

    Federal Laboratory Consortium — The HFIR at Oak Ridge National Laboratory is a light-water cooled and moderated reactor that is the United States’ highest flux reactor-based neutron source. HFIR...

  4. Low variation in the polymorphic Clock gene poly-Q region despite population genetic structure across barn swallow (Hirundo rustica populations.

    Directory of Open Access Journals (Sweden)

    Roi Dor

    Full Text Available Recent studies of several species have reported a latitudinal cline in the circadian clock gene, Clock, which influences rhythms in both physiology and behavior. Latitudinal variation in this gene may hence reflect local adaptation to seasonal variation. In some bird populations, there is also an among-individual association between Clock poly-Q genotype and clutch initiation date and incubation period. We examined Clock poly-Q allele variation in the Barn Swallow (Hirundo rustica, a species with a cosmopolitan geographic distribution and considerable variation in life-history traits that may be influenced by the circadian clock. We genotyped Barn Swallows from five populations (from three subspecies and compared variation at the Clock locus to that at microsatellite loci and mitochondrial DNA (mtDNA. We found very low variation in the Clock poly-Q region, as >96% of individuals were homozygous, and the two other alleles at this locus were globally rare. Genetic differentiation based on the Clock poly-Q locus was not correlated with genetic differentiation based on either microsatellite loci or mtDNA sequences. Our results show that high diversity in Clock poly-Q is not general across avian species. The low Clock variation in the background of heterogeneity in microsatellite and mtDNA loci in Barn Swallows may be an outcome of stabilizing selection on the Clock locus.

  5. Genetic divergence analysis of the Common Barn Owl Tyto alba (Scopoli, 1769) and the Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile using COI sequence

    Science.gov (United States)

    Colihueque, Nelson; Gantz, Alberto; Rau, Jaime Ricardo; Parraguez, Margarita

    2015-01-01

    Abstract In this paper new mitochondrial COI sequences of Common Barn Owl Tyto alba (Scopoli, 1769) and Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile are reported and compared with sequences from other parts of the World. The intraspecific genetic divergence (mean p-distance) was 4.6 to 5.5% for the Common Barn Owl in comparison with specimens from northern Europe and Australasia and 3.1% for the Short-eared Owl with respect to samples from north America, northern Europe and northern Asia. Phylogenetic analyses revealed three distinctive groups for the Common Barn Owl: (i) South America (Chile and Argentina) plus Central and North America, (ii) northern Europe and (iii) Australasia, and two distinctive groups for the Short-eared Owl: (i) South America (Chile and Argentina) and (ii) north America plus northern Europe and northern Asia. The level of genetic divergence observed in both species exceeds the upper limit of intraspecific comparisons reported previously for Strigiformes. Therefore, this suggests that further research is needed to assess the taxonomic status, particularly for the Chilean populations that, to date, have been identified as belonging to these species through traditional taxonomy. PMID:26668551

  6. Genetic divergence analysis of the Common Barn Owl Tyto alba (Scopoli, 1769) and the Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile using COI sequence.

    Science.gov (United States)

    Colihueque, Nelson; Gantz, Alberto; Rau, Jaime Ricardo; Parraguez, Margarita

    2015-01-01

    In this paper new mitochondrial COI sequences of Common Barn Owl Tyto alba (Scopoli, 1769) and Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile are reported and compared with sequences from other parts of the World. The intraspecific genetic divergence (mean p-distance) was 4.6 to 5.5% for the Common Barn Owl in comparison with specimens from northern Europe and Australasia and 3.1% for the Short-eared Owl with respect to samples from north America, northern Europe and northern Asia. Phylogenetic analyses revealed three distinctive groups for the Common Barn Owl: (i) South America (Chile and Argentina) plus Central and North America, (ii) northern Europe and (iii) Australasia, and two distinctive groups for the Short-eared Owl: (i) South America (Chile and Argentina) and (ii) north America plus northern Europe and northern Asia. The level of genetic divergence observed in both species exceeds the upper limit of intraspecific comparisons reported previously for Strigiformes. Therefore, this suggests that further research is needed to assess the taxonomic status, particularly for the Chilean populations that, to date, have been identified as belonging to these species through traditional taxonomy.

  7. Low Variation in the Polymorphic Clock Gene Poly-Q Region Despite Population Genetic Structure across Barn Swallow (Hirundo rustica) Populations

    Science.gov (United States)

    Dor, Roi; Lovette, Irby J.; Safran, Rebecca J.; Billerman, Shawn M.; Huber, Gernot H.; Vortman, Yoni; Lotem, Arnon; McGowan, Andrew; Evans, Matthew R.; Cooper, Caren B.; Winkler, David W.

    2011-01-01

    Recent studies of several species have reported a latitudinal cline in the circadian clock gene, Clock, which influences rhythms in both physiology and behavior. Latitudinal variation in this gene may hence reflect local adaptation to seasonal variation. In some bird populations, there is also an among-individual association between Clock poly-Q genotype and clutch initiation date and incubation period. We examined Clock poly-Q allele variation in the Barn Swallow (Hirundo rustica), a species with a cosmopolitan geographic distribution and considerable variation in life-history traits that may be influenced by the circadian clock. We genotyped Barn Swallows from five populations (from three subspecies) and compared variation at the Clock locus to that at microsatellite loci and mitochondrial DNA (mtDNA). We found very low variation in the Clock poly-Q region, as >96% of individuals were homozygous, and the two other alleles at this locus were globally rare. Genetic differentiation based on the Clock poly-Q locus was not correlated with genetic differentiation based on either microsatellite loci or mtDNA sequences. Our results show that high diversity in Clock poly-Q is not general across avian species. The low Clock variation in the background of heterogeneity in microsatellite and mtDNA loci in Barn Swallows may be an outcome of stabilizing selection on the Clock locus. PMID:22216124

  8. Reactor operation safety information document

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    The report contains a reactor facility description which includes K, P, and L reactor sites, structures, operating systems, engineered safety systems, support systems, and process and effluent monitoring systems; an accident analysis section which includes cooling system anomalies, radioactive materials releases, and anticipated transients without scram; a summary of onsite doses from design basis accidents; severe accident analysis (reactor core disruption); a description of operating contractor organization and emergency planning; and a summary of reactor safety evolution. (MB)

  9. Thermal Reactor Safety

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-01

    Information is presented concerning fire risk and protection; transient thermal-hydraulic analysis and experiments; class 9 accidents and containment; diagnostics and in-service inspection; risk and cost comparison of alternative electric energy sources; fuel behavior and experiments on core cooling in LOCAs; reactor event reporting analysis; equipment qualification; post facts analysis of the TMI-2 accident; and computational methods.

  10. Chromatographic and Related Reactors.

    Science.gov (United States)

    1988-01-07

    special information about effects of surface heteroge- neity in the methanation reaction. Studies of an efficient multicolumn assembly for measuring...of organic basic catalysts such as pyridine and 4-methylpicoline. It was demonstrated that the chromatographic reactor gave special information about...Programmed Reaction to obtain special information about surface heterogeneity in the methanation reaction. Advantages of stopped flow over steady state

  11. Nuclear Reactors and Technology

    Energy Technology Data Exchange (ETDEWEB)

    Cason, D.L.; Hicks, S.C. [eds.

    1992-01-01

    This publication Nuclear Reactors and Technology (NRT) announces on a monthly basis the current worldwide information available from the open literature on nuclear reactors and technology, including all aspects of power reactors, components and accessories, fuel elements, control systems, and materials. This publication contains the abstracts of DOE reports, journal articles, conference papers, patents, theses, and monographs added to the Energy Science and Technology Database during the past month. Also included are US information obtained through acquisition programs or interagency agreements and international information obtained through the International Energy Agency`s Energy Technology Data Exchange or government-to-government agreements. The digests in NRT and other citations to information on nuclear reactors back to 1948 are available for online searching and retrieval on the Energy Science and Technology Database and Nuclear Science Abstracts (NSA) database. Current information, added daily to the Energy Science and Technology Database, is available to DOE and its contractors through the DOE Integrated Technical Information System. Customized profiles can be developed to provide current information to meet each user`s needs.

  12. Fusion reactor materials

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1989-01-01

    This paper discuses the following topics on fusion reactor materials: irradiation, facilities, test matrices, and experimental methods; dosimetry, damage parameters, and activation calculations; materials engineering and design requirements; fundamental mechanical behavior; radiation effects; development of structural alloys; solid breeding materials; and ceramics.

  13. WATER BOILER REACTOR

    Science.gov (United States)

    King, L.D.P.

    1960-11-22

    As its name implies, this reactor utilizes an aqueous solution of a fissionable element salt, and is also conventional in that it contains a heat exchanger cooling coil immersed in the fuel. Its novelty lies in the utilization of a cylindrical reactor vessel to provide a critical region having a large and constant interface with a supernatant vapor region, and the use of a hollow sleeve coolant member suspended from the cover assembly in coaxial relation with the reactor vessel. Cool water is circulated inside this hollow coolant member, and a gap between its outer wall and the reactor vessel is used to carry off radiolytic gases for recombination in an external catalyst chamber. The central passage of the coolant member defines a reflux condenser passage into which the externally recombined gases are returned and condensed. The large and constant interface between fuel solution and vapor region prevents the formation of large bubbles and minimizes the amount of fuel salt carried off by water vapor, thus making possible higher flux densities, specific powers and power densities.

  14. The First Reactor.

    Science.gov (United States)

    Department of Energy, Washington, DC.

    On December 2, 1942, in a racquet court underneath the West Stands of Stagg Field at the University of Chicago, a team of scientists led by Enrico Fermi created the first controlled, self-sustaining nuclear chain reaction. This updated and revised story of the first reactor (or "pile") is based on postwar interviews (as told to Corbin…

  15. MULTISTAGE FLUIDIZED BED REACTOR

    Science.gov (United States)

    Jonke, A.A.; Graae, J.E.A.; Levitz, N.M.

    1959-11-01

    A multistage fluidized bed reactor is described in which each of a number of stages is arranged with respect to an associated baffle so that a fluidizing gas flows upward and a granular solid downward through the stages and baffles, whereas the granular solid stopsflowing downward when the flow of fluidizing gas is shut off.

  16. Brazilian multipurpose reactor

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2014-07-01

    The Brazilian Multipurpose Reactor (RMB) Project is an action of the Federal Government, through the Ministry of Science Technology and Innovation (MCTI) and has its execution under the responsibility of the Brazilian National Nuclear Energy Commission (CNEN). Within the CNEN, the project is coordinated by the Research and Development Directorate (DPD) and developed through research units of this board: Institute of Nuclear Energy Research (IPEN); Nuclear Engineering Institute (IEN); Centre for Development of Nuclear Technology (CDTN); Regional Center of Nuclear Sciences (CRCN-NE); and Institute of Radiation Protection and Dosimetry (IRD). The Navy Technological Center in Sao Paulo (CTMSP) and also the participation of other research centers, universities, laboratories and companies in the nuclear sector are important and strategic partnerships. The conceptual design and the safety analysis of the reactor and main facilities, related to nuclear and environmental licensing, are performed by technicians of the research units of DPD / CNEN. The basic design was contracted to engineering companies as INTERTHECNE from Brazil and INVAP from Argentine. The research units from DPD/CNEN are also responsible for the design verification on all engineering documents developed by the contracted companies. The construction and installation should be performed by specific national companies and international partnerships. The Nuclear Reactor RMB will be a open pool type reactor with maximum power of 30 MW and have the OPAL nuclear reactor of 20 MW, built in Australia and designed by INVAP, as reference. The RMB reactor core will have a 5x5 configuration, consisting of 23 elements fuels (EC) of U{sub 3}Si{sub 2} dispersion-type Al having a density of up to 3.5 gU/cm{sup 3} and enrichment of 19.75% by weight of {sup 23{sup 5}}U. Two positions will be available in the core for materials irradiation devices. The main objectives of the RMB Reactor and the other nuclear and radioactive

  17. Modeling Chemical Reactors I: Quiescent Reactors

    CERN Document Server

    Michoski, C E; Schmitz, P G

    2010-01-01

    We introduce a fully generalized quiescent chemical reactor system in arbitrary space $\\vdim =1,2$ or 3, with $n\\in\\mathbb{N}$ chemical constituents $\\alpha_{i}$, where the character of the numerical solution is strongly determined by the relative scaling between the local reactivity of species $\\alpha_{i}$ and the local functional diffusivity $\\mathscr{D}_{ij}(\\alpha)$ of the reaction mixture. We develop an operator time-splitting predictor multi-corrector RK--LDG scheme, and utilize $hp$-adaptivity relying only on the entropy $\\mathscr{S}_{\\mathfrak{R}}$ of the reactive system $\\mathfrak{R}$. This condition preserves these bounded nonlinear entropy functionals as a necessarily enforced stability condition on the coupled system. We apply this scheme to a number of application problems in chemical kinetics; including a difficult classical problem arising in nonequilibrium thermodynamics known as the Belousov-Zhabotinskii reaction where we utilize a concentration-dependent diffusivity tensor $\\mathscr{D}_{ij}(...

  18. 天然气水暖集中供热密集烤房设备的研究%Study on the bulk curing barn with central water heating by natural gas

    Institute of Scientific and Technical Information of China (English)

    任杰; 孙福山; 刘治清; 徐世峰; 许建设; 沈始权

    2013-01-01

      针对我国烟叶烘烤设备对煤炭依赖度高、环境污染重、烘烤用工量大的问题,利用液化天然气(LNG)为气源,集成LNG 气化技术、水暖集中供热技术,设计建造了天然气水暖集中供热密集烤房,并进行了烘烤试验。结果表明:天然气水暖集中供热密集烤房升温准,控温稳,能够满足烤烟密集烘烤对温湿度的要求。虽然较燃煤密集烤房能耗成本有所增加,但改善了烤后烟叶的外观质量,提高了上等烟比例,减少了烘烤用工和大气污染物排放量。%In order to resolve the problems of the bulk curing barn which depended on coal, contaminated environment and needed much labor, the bulk curing barn with central water heating by natural gas (gas fired bulk curing barn) utilizing liquefied natural gas as gas source was designed and built using liquefied natural gas gasification technique and central water heating supply technique. Effects of the bulk curing barn with central water heating by natural gas were investigated. The results indicated that heating-up of the gas fired bulk curing barn was very quick and sensitive to meet the temperature and humidity requirements of tobacco flue-curing. The gas fired bulk curing barn improved the surface quality of cured tobacco leaves and increased the proportion of classy cured tobacco leaves. Employment and emission amount of atmospheric pollutant of the gas fired bulk curing barn were less than that of the coal fired bulk curing barn, but the final cost of the gas fired bulk curing barn was more than that of the coal fired bulk curing barn.

  19. Barnes-Evans relations for dwarfs with an application to the determination of distances to cataclysmic variables

    CERN Document Server

    Beuermann, K

    2006-01-01

    Barnes-Evans type relations provide an empirical relationship between the surface brightness of stars and their color. They are widely used for measuring the distances to stars of known radii, as the Roche-lobe filling secondaries in cataclysmic variables (CVs). The calibration of the surface brightness of field dwarfs of near-solar metalicity with spectral types A0 to L8 covers all secondary spectral types detectable in CVs and related objects and will aid in the measurement of their distances. The calibrations are based on the radii of field dwarfs measured by the Infrared Flux Method and by interferometry. Published photometry is used and homogenized to the Cousins Rc and Ic and the CIT JHK photometric systems. The narrow band surface brightness at 7500A is based on our own and published spectrophotometry. Care is taken to select the dwarfs for near-solar metalicity, appropriate to CVs, and to avoid errors caused by unrecognized binarity. Relations are provided for the surface brightness in V, Rc, Ic, J, H...

  20. Effect of voluntary physical exercise and post-training epinephrine on acquisition of a spatial task in the barnes maze.

    Science.gov (United States)

    Jacotte-Simancas, Alejandra; Costa-Miserachs, David; Torras-Garcia, Meritxell; Coll-Andreu, Margalida; Portell-Cortés, Isabel

    2013-06-15

    A number of experiments have shown that physical exercise improves acquisition and retention for a variety of learning tasks in rodents. Most of these works have been conducted with tasks associated with a considerable level of stress, physical effort and/or food deprivation that might interact with exercise, thus hindering the interpretation of the results. On the other hand, it is well established that post-training epinephrine is able to facilitate memory consolidation, but only a few works have studied its effect on the process of acquisition. The present work was aimed at studying whether 17 days of voluntary physical exercise (running wheels) and/or post-training epinephrine (0.01 or 0.05 mg/kg) could improve the acquisition of a spatial task in the Barnes maze, and whether the combination of the two treatments have additive effects. Our results showed that exercise improved acquisition, and 0.01 mg/kg of epinephrine tended to enhance it, by reducing the distance needed to find the escape hole. The combination of both treatments failed to further improve the acquisition level. We concluded that both treatments exerted their effect on acquisition by enhancing the process of learning itself, and that exercise is able to improve acquisition even using tasks with a low level of stress and physical effort.

  1. Migration phenology and breeding success are predicted by methylation of a photoperiodic gene in the barn swallow.

    Science.gov (United States)

    Saino, Nicola; Ambrosini, Roberto; Albetti, Benedetta; Caprioli, Manuela; De Giorgio, Barbara; Gatti, Emanuele; Liechti, Felix; Parolini, Marco; Romano, Andrea; Romano, Maria; Scandolara, Chiara; Gianfranceschi, Luca; Bollati, Valentina; Rubolini, Diego

    2017-03-31

    Individuals often considerably differ in the timing of their life-cycle events, with major consequences for individual fitness, and, ultimately, for population dynamics. Phenological variation can arise from genetic effects but also from epigenetic modifications in DNA expression and translation. Here, we tested if CpG methylation at the poly-Q and 5'-UTR loci of the photoperiodic Clock gene predicted migration and breeding phenology of long-distance migratory barn swallows (Hirundo rustica) that were tracked year-round using light-level geolocators. Increasing methylation at Clock poly-Q was associated with earlier spring departure from the African wintering area, arrival date at the European breeding site, and breeding date. Higher methylation levels also predicted increased breeding success. Thus, we showed for the first time in any species that CpG methylation at a candidate gene may affect phenology and breeding performance. Methylation at Clock may be a candidate mechanism mediating phenological responses of migratory birds to ongoing climate change.

  2. Importance of Farmland in Urbanized Areas as a Landscape Component for Barn Swallows ( Hirundo rustica) Nesting on Concrete Buildings

    Science.gov (United States)

    Osawa, Takeshi

    2015-05-01

    Urbanization is one of the key factors in the population declines of many species. Conversely, some species may favor urbanized areas. The barn swallow Hirundo rustica is well known to breed in urban areas of Japan, and uses both urban and farmland areas as habitat during the breeding season. Specifically, this species often nests on concrete buildings and feeds in surrounding farmland. Therefore, it was hypothesized that H. rustica is not strongly influenced by heavy urbanization and benefits from farmland areas, even if they are not near its nests. In this study, I evaluated the landscape components around H. rustica nests situated on concrete buildings, focusing on both urbanized and farmland areas. In particular, I explored the occurrence of H. rustica nests at train stations in the Kinki region of Japan. Assisted by 124 citizen scientists, I analyzed the landscape components around the train stations at multiple spatial scales. Results showed that the occurrence of H. rustica nests was negatively influenced by both urbanized land area and road density, whereas nest occurrence was positively influenced by farmland area and river density. These results suggest that H. rustica does not prefer urbanized areas overall, but can rather utilize urbanized areas primarily as nesting spots. Therefore, H. rustica cannot breed in heavily urbanized areas without feeding sites such as farmland or riparian areas.

  3. Description of 44 biosecurity errors while entering and exiting poultry barns based on video surveillance in Quebec, Canada.

    Science.gov (United States)

    Racicot, Manon; Venne, Daniel; Durivage, André; Vaillancourt, Jean-Pierre

    2011-07-01

    The effectiveness of biosecurity measures depends largely on the consistency of their applications by all those involved in poultry production. Unfortunately, poor biosecurity compliance has been reported repeatedly in poultry, as well in all other major animal productions. As part of a larger study, we conducted an investigation on eight poultry farms in Quebec, Canada, to evaluate compliance of existing biosecurity measures using hidden cameras. The objectives were to evaluate and describe the application of biosecurity measures when entering and exiting poultry barns. A total of 44 different mistakes were observed from 883 visits done by 102 different individuals. On average, four errors were recorded per visit. The maximum number of errors made by one individual during one visit was 14. People observed over several visits made on average six different errors. Twenty-seven out of the 44 errors (61.4%) were related to area delimitation (clean versus contaminated), six to boots (13.6%), five to hand washing (11.4%), three to coveralls (6.8%) and three to logbooks (6.8%). The nature and frequency of errors suggest a lack of understanding of biosecurity principles. There is thus a need to improve biosecurity training by making educational material available to all poultry personnel demonstrating why and how to apply biosecurity measures.

  4. Expression of Multiple Sexual Signals by Fathers and Sons in the East-Mediterranean Barn Swallow: Are Advertising Strategies Heritable?

    Science.gov (United States)

    Vortman, Yoni; Safran, Rebecca J.; Reiner Brodetzki, Tali; Dor, Roi; Lotem, Arnon

    2015-01-01

    The level of expression of sexually selected traits is generally determined by genes, environment and their interaction. In species that use multiple sexual signals which may be costly to produce, investing in the expression of one sexual signal may limit the expression of the other, favoring the evolution of a strategy for resource allocation among signals. As a result, even when the expression of sexual signals is condition dependent, the relative level of expression of each signal may be heritable. We tested this hypothesis in the East-Mediterranean barn swallow (Hirundo rustica transitiva), in which males have been shown to express two uncorrelated sexual signals: red-brown ventral coloration, and long tail streamers. We show that variation in both signals may partially be explained by age, as well as by paternal origin (genetic father-son regressions), but that the strongest similarity between fathers and sons is the relative allocation towards one trait or the other (relative expression index), rather than the expression of the traits themselves. These results suggest that the expression of one signal is not independent of the other, and that genetic strategies for resource allocation among sexual signals may be selected for during the evolution of multiple sexual signals. PMID:25679206

  5. Expression of multiple sexual signals by fathers and sons in the East-Mediterranean barn swallow: are advertising strategies heritable?

    Directory of Open Access Journals (Sweden)

    Yoni Vortman

    Full Text Available The level of expression of sexually selected traits is generally determined by genes, environment and their interaction. In species that use multiple sexual signals which may be costly to produce, investing in the expression of one sexual signal may limit the expression of the other, favoring the evolution of a strategy for resource allocation among signals. As a result, even when the expression of sexual signals is condition dependent, the relative level of expression of each signal may be heritable. We tested this hypothesis in the East-Mediterranean barn swallow (Hirundo rustica transitiva, in which males have been shown to express two uncorrelated sexual signals: red-brown ventral coloration, and long tail streamers. We show that variation in both signals may partially be explained by age, as well as by paternal origin (genetic father-son regressions, but that the strongest similarity between fathers and sons is the relative allocation towards one trait or the other (relative expression index, rather than the expression of the traits themselves. These results suggest that the expression of one signal is not independent of the other, and that genetic strategies for resource allocation among sexual signals may be selected for during the evolution of multiple sexual signals.

  6. Cassia spectabilis (DC Irwin et Barn: A Promising Traditional Herb in Health Improvement

    Directory of Open Access Journals (Sweden)

    Subramanian Deivanai

    2012-08-01

    Full Text Available The genus Cassia, comprising about 600 species widely distributed worldwide is well known for its diverse biological and pharmacological properties. Cassia spectabilis (sin Senna spectabilis (DC Irwin et Barn (Fabaceae is widely grown as an ornamental plant in tropical and subtropical areas. C. spectabilis has been commonly used in traditional medicine for many years. Information in the biomedical literature has indicated the presence of a variety of medicinally-important chemical constituents in C. spectabilis. Pharmacological studies by various groups of investigators have shown that C. spectabilis possesses significant biological activity, such as antibacterial, antibiofilm, antifungal and antioxidant properties. Beside this, toxicity studies of this plant have revealed no toxic effect on mice. In view of the immense medicinal importance of C. spectabilis, this review aimed at compiling all currently available information on C. spectabilis’s botany, phytochemistry, pharmacology, and mechanism of actions, toxicology and its ethnomedicinal uses.

  7. Migration phenology and breeding success are predicted by methylation of a photoperiodic gene in the barn swallow

    Science.gov (United States)

    Saino, Nicola; Ambrosini, Roberto; Albetti, Benedetta; Caprioli, Manuela; De Giorgio, Barbara; Gatti, Emanuele; Liechti, Felix; Parolini, Marco; Romano, Andrea; Romano, Maria; Scandolara, Chiara; Gianfranceschi, Luca; Bollati, Valentina; Rubolini, Diego

    2017-01-01

    Individuals often considerably differ in the timing of their life-cycle events, with major consequences for individual fitness, and, ultimately, for population dynamics. Phenological variation can arise from genetic effects but also from epigenetic modifications in DNA expression and translation. Here, we tested if CpG methylation at the poly-Q and 5′-UTR loci of the photoperiodic Clock gene predicted migration and breeding phenology of long-distance migratory barn swallows (Hirundo rustica) that were tracked year-round using light-level geolocators. Increasing methylation at Clock poly-Q was associated with earlier spring departure from the African wintering area, arrival date at the European breeding site, and breeding date. Higher methylation levels also predicted increased breeding success. Thus, we showed for the first time in any species that CpG methylation at a candidate gene may affect phenology and breeding performance. Methylation at Clock may be a candidate mechanism mediating phenological responses of migratory birds to ongoing climate change. PMID:28361883

  8. Alternative approaches to fusion. [reactor design and reactor physics for Tokamak fusion reactors

    Science.gov (United States)

    Roth, R. J.

    1976-01-01

    The limitations of the Tokamak fusion reactor concept are discussed and various other fusion reactor concepts are considered that employ the containment of thermonuclear plasmas by magnetic fields (i.e., stellarators). Progress made in the containment of plasmas in toroidal devices is reported. Reactor design concepts are illustrated. The possibility of using fusion reactors as a power source in interplanetary space travel and electric power plants is briefly examined.

  9. The Study Result of the Solar Energy Application on Bulk Curing Barn%密集烤房的太阳能改造与应用研究

    Institute of Scientific and Technical Information of China (English)

    汪炳华; 徐天养; 肖华; 向成高; 何兵; 江红甲; 党云波; 李润涛

    2011-01-01

    为在烤烟烘烤期间利用太阳能替代部分燃煤,以达到节能减排的目的,对现有的密集烤房进行太阳能改造,在屋顶加装太阳能加热室,吸收太阳能并加热太阳能加热室内空气,高温空气通过内循环管道与烤房的加热室、装烟室连通,提供辅助热源。太阳能循环风机由温差控制器控制。对改造的太阳能密集烤房进行烘烤效应研究,结果表明密集型烤房的太阳能改造简单易行,经济实用,节能效果明显;太阳能提供的热量可满足烟叶烘烤前期的需要,每千克干烟耗能比改造前降低20%~24%,烘烤烟叶质量与普通密集烤房所烤烟叶质量相当,社会效益与经济效益明显,在光照好的烟区具有一定的推广价值。%In order to achieve energy conservation and emission reduction,a combination of energy from solar and coal has been built up based on a bulk curing barn by installing a solar heat system on the top of a bulk curing barn roof which are comprised of a heat room with valve controlled by a fan,lighting and heating transformation sheet and automatic temperature monitor.This study was focused on how much effect of the solar heating system could be as a supplemental energy to curing process,It has been turned out that not only a significant energy reduction has been achieved,but this modification bulk curing barn were easily constructed and economical,the solar energy could supply all heating from the early stage of tobacco curing process.The modified solar curing barn could save 20%-24%coal consumption per kg drying leaf as the one from a bulk curing barn at achieving the equivalent leaf quality.It has shown an encouraging prospective of benefit for economy and society especially on emission reduction and worthwhile for those area with abundant solar resource to extend this technology.

  10. Reactor monitoring using antineutrino detectors

    Science.gov (United States)

    Bowden, N. S.

    2011-08-01

    Nuclear reactors have served as the antineutrino source for many fundamental physics experiments. The techniques developed by these experiments make it possible to use these weakly interacting particles for a practical purpose. The large flux of antineutrinos that leaves a reactor carries information about two quantities of interest for safeguards: the reactor power and fissile inventory. Measurements made with antineutrino detectors could therefore offer an alternative means for verifying the power history and fissile inventory of a reactor as part of International Atomic Energy Agency (IAEA) and/or other reactor safeguards regimes. Several efforts to develop this monitoring technique are underway worldwide.

  11. Reactor vessel support system. [LMFBR

    Science.gov (United States)

    Golden, M.P.; Holley, J.C.

    1980-05-09

    A reactor vessel support system includes a support ring at the reactor top supported through a box ring on a ledge of the reactor containment. The box ring includes an annular space in the center of its cross-section to reduce heat flow and is keyed to the support ledge to transmit seismic forces from the reactor vessel to the containment structure. A coolant channel is provided at the outside circumference of the support ring to supply coolant gas through the keyways to channels between the reactor vessel and support ledge into the containment space.

  12. Methanogenesis in Thermophilic Biogas Reactors

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    1995-01-01

    Methanogenesis in thermophilic biogas reactors fed with different wastes is examined. The specific methanogenic activity with acetate or hydrogen as substrate reflected the organic loading of the specific reactor examined. Increasing the loading of thermophilic reactors stabilized the process...... as indicated by a lower concentration of volatile fatty acids in the effluent from the reactors. The specific methanogenic activity in a thermophilic pilot-plant biogas reactor fed with a mixture of cow and pig manure reflected the stability of the reactor. The numbers of methanogens counted by the most...... against Methanothrix soehngenii or Methanothrix CALS-I in any of the thermophilic biogas reactors examined. Studies using 2-14C-labeled acetate showed that at high concentrations (more than approx. 1 mM) acetate was metabolized via the aceticlastic pathway, transforming the methyl-group of acetate...

  13. MEANS FOR COOLING REACTORS

    Science.gov (United States)

    Wheeler, J.A.

    1957-11-01

    A design of a reactor is presented in which the fuel elements may be immersed in a liquid coolant when desired without the necessity of removing them from the reactor structure. The fuel elements, containing the fissionable material are in plate form and are disposed within spaced slots in a moderator material, such as graphite to form the core. Adjacent the core is a tank containing the liquid coolant. The fuel elements are mounted in spaced relationship on a rotatable shaft which is located between the core and the tank so that by rotation of the shaft the fuel elements may be either inserted in the slots in the core to sustain a chain reaction or immersed in the coolant.

  14. Compact fusion reactors

    CERN Document Server

    CERN. Geneva

    2015-01-01

    Fusion research is currently to a large extent focused on tokamak (ITER) and inertial confinement (NIF) research. In addition to these large international or national efforts there are private companies performing fusion research using much smaller devices than ITER or NIF. The attempt to achieve fusion energy production through relatively small and compact devices compared to tokamaks decreases the costs and building time of the reactors and this has allowed some private companies to enter the field, like EMC2, General Fusion, Helion Energy, Lawrenceville Plasma Physics and Lockheed Martin. Some of these companies are trying to demonstrate net energy production within the next few years. If they are successful their next step is to attempt to commercialize their technology. In this presentation an overview of compact fusion reactor concepts is given.

  15. Interaktionens betydelse för barns lärande - en studie av barns möte med slöjd i förskolan

    Directory of Open Access Journals (Sweden)

    Eva Ahlskog-Björkman

    2014-06-01

    Full Text Available Syftet med den här artikeln är att diskutera på vilket sätt interaktion och socialt samspel har betydelse för hur barn i förskolan kan engageras i en lärandeprocess. Den empiriska studien utgörs av en  videofilmad episod över en vävaktivitet i förskola. Genom att använda videografisk observation kan mänsklig aktivitet beskrivas och av den anledningen används  videografi som metodologisk ansats. I studien analyseras på vilket sätt interaktionen mellan de som är närvarande, oberoende av barnens ålder, kan bidra till att stimulera den lärande aktiviteten. Barnens slöjdaktivitet beaktas ur ett sociokulturellt lärandeperspektiv. Ett centralt tema inom detta perspektiv är kommunikation där språket och redskapen står för de medierande faktorerna. Barnens kontakt med redskapen och deras upplevelser och erfarande av slöjdaktiviteten diskuteras i relation till den närmaste utvecklingszonen. Ytterligare beaktas den videofilmade sekvensen ur ett socialt perspektiv där barnpedagogens agerande gentemot barnen lyfts fram och diskuteras. Analys och tolkning av datamaterialet strävar efter att synliggöra mänsklig interaktion och dess betydelse för att motivera och engagera barnen i deras slöjdaktivitet.  

  16. Reactor Neutrino Spectra

    OpenAIRE

    Hayes, A. C.; Vogel, Petr

    2016-01-01

    We present a review of the antineutrino spectra emitted from reactors. Knowledge of these spectra and their associated uncertainties is crucial for neutrino oscillation studies. The spectra used to date have been determined either by converting measured electron spectra to antineutrino spectra or by summing over all of the thousands of transitions that make up the spectra, using modern databases as input. The uncertainties in the subdominant corrections to β-decay plague both methods, and we ...

  17. REACTOR MODERATOR STRUCTURE

    Science.gov (United States)

    Greenstreet, B.L.

    1963-12-31

    A system for maintaining the alignment of moderator block structures in reactors is presented. Integral restraining grids are placed between each layer of blocks in the moderator structure, at the top of the uppermost layer, and at the bottom of the lowermost layer. Slots are provided in the top and bottom surfaces of the moderator blocks so as to provide a keying action with the grids. The grids are maintained in alignment by vertical guiding members disposed about their peripheries. (AEC)

  18. BOILER-SUPERHEATED REACTOR

    Science.gov (United States)

    Heckman, T.P.

    1961-05-01

    A nuclear power reactor of the type in which a liquid moderator-coolant is transformed by nuclear heating into a vapor that may be used to drive a turbo- generator is described. The core of this reactor comprises a plurality of freely suspended tubular fuel elements, called fuel element trains, within which nonboiling pressurized liquid moderator-coolant is preheated and sprayed through orifices in the walls of the trains against the outer walls thereof to be converted into vapor. Passage of the vapor ovcr other unwetted portions of the outside of the fuel elements causes the steam to be superheated. The moderatorcoolant within the fuel elements remains in the liqUid state, and that between the fuel elements remains substantiaily in the vapor state. A unique liquid neutron-absorber control system is used. Advantages expected from the reactor design include reduced fuel element failure, increased stability of operation, direct response to power demand, and circulation of a minimum amount of liquid moderatorcoolant. (A.G.W.)

  19. Nuclear research reactors in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Cota, Anna Paula Leite; Mesquita, Amir Zacarias, E-mail: aplc@cdtn.b, E-mail: amir@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-07-01

    The rising concerns about global warming and energy security have spurred a revival of interest in nuclear energy, giving birth to a 'nuclear power renaissance' in several countries in the world. Particularly in Brazil, in the recent years, the nuclear power renaissance can be seen in the actions that comprise its nuclear program, summarily the increase of the investments in nuclear research institutes and the government target to design and build the Brazilian Multipurpose research Reactor (BMR). In the last 50 years, Brazilian research reactors have been used for training, for producing radioisotopes to meet demands in industry and nuclear medicine, for miscellaneous irradiation services and for academic research. Moreover, the research reactors are used as laboratories to develop technologies in power reactors, which are evaluated today at around 450 worldwide. In this application, those reactors become more viable in relation to power reactors by the lowest cost, by the operation at low temperatures and, furthermore, by lower demand for nuclear fuel. In Brazil, four research reactors were installed: the IEA-R1 and the MB-01 reactors, both at the Instituto de Pesquisas Energeticas Nucleares (IPEN, Sao Paulo); the Argonauta, at the Instituto de Engenharia Nuclear (IEN, Rio de Janeiro) and the IPR-R1 TRIGA reactor, at the Centro de Desenvolvimento da Tecnologia Nuclear (CDTN, Belo Horizonte). The present paper intends to enumerate the characteristics of these reactors, their utilization and current academic research. Therefore, through this paper, we intend to collaborate on the BMR project. (author)

  20. Thermionic Reactor Design Studies

    Energy Technology Data Exchange (ETDEWEB)

    Schock, Alfred

    1994-06-01

    During the 1960's and early 70's the author performed extensive design studies, analyses, and tests aimed at thermionic reactor concepts that differed significantly from those pursued by other investigators. Those studies, like most others under Atomic Energy Commission (AEC and DOE) and the National Aeronautics and Space Administration (NASA) sponsorship, were terminated in the early 1970's. Some of this work was previously published, but much of it was never made available in the open literature. U.S. interest in thermionic reactors resumed in the early 80's, and was greatly intensified by reports about Soviet ground and flight tests in the late 80's. This recent interest resulted in renewed U.S. thermionic reactor development programs, primarily under Department of Defense (DOD) and Department of Energy (DOE) sponsorship. Since most current investigators have not had an opportunity to study all of the author's previous work, a review of the highlights of that work may be of value to them. The present paper describes some of the author's conceptual designs and their rationale, and the special analytical techniques developed to analyze their performance. The basic designs, first published in 1963, are based on single-cell converters, either double-ended diodes extending over the full height of the reactor core or single-ended diodes extending over half the core height. In that respect they are similar to the thermionic fuel elements employed in the Topaz-2 reactor subsequently developed in the Soviet Union, copies of which were recently imported by the U.S. As in the Topaz-2 case, electrically heated steady-state performance tests of the converters are possible before fueling. Where the author's concepts differed from the later Topaz-2 design was in the relative location of the emitter and the collector. Placing the fueled emitter on the outside of the cylindrical diodes permits much higher axial conductances to reduce ohmic

  1. Early-Life Telomere Dynamics Differ between the Sexes and Predict Growth in the Barn Swallow (Hirundo rustica.

    Directory of Open Access Journals (Sweden)

    Marco Parolini

    Full Text Available Telomeres are conserved DNA-protein structures at the termini of eukaryotic chromosomes which contribute to maintenance of genome integrity, and their shortening leads to cell senescence, with negative consequences for organismal functions. Because telomere erosion is influenced by extrinsic and endogenous factors, telomere dynamics may provide a mechanistic basis for evolutionary and physiological trade-offs. Yet, knowledge of fundamental aspects of telomere biology under natural selection regimes, including sex- and context-dependent variation in early-life, and the covariation between telomere dynamics and growth, is scant. In this study of barn swallows (Hirundo rustica we investigated the sex-dependent telomere erosion during nestling period, and the covariation between relative telomere length and body and plumage growth. Finally, we tested whether any covariation between growth traits and relative telomere length depends on the social environment, as influenced by sibling sex ratio. Relative telomere length declined on average over the period of nestling maximal growth rate (between 7 and 16 days of age and differently covaried with initial relative telomere length in either sex. The frequency distribution of changes in relative telomere length was bimodal, with most nestlings decreasing and some increasing relative telomere length, but none of the offspring traits predicted the a posteriori identified group to which individual nestlings belonged. Tail and wing length increased with relative telomere length, but more steeply in males than females, and this relationship held both at the within- and among-broods levels. Moreover, the increase in plumage phenotypic values was steeper when the sex ratio of an individual's siblings was female-biased. Our study provides evidence for telomere shortening during early life according to subtly different dynamics in either sex. Furthermore, it shows that the positive covariation between growth and

  2. Mammal prey of the Barn Owl (Tyto alba in Parque Luro Reserve, La Pampa, Argentina

    Directory of Open Access Journals (Sweden)

    Sergio Tiranti

    1994-05-01

    Full Text Available Abstract The diet of the barn owl was studied through the analysis of pellets obtained in various sites within the Parque Luro reserve, located in an area of xerophyte Caldén forests. The study of 1241 prey items revealed a high dominance of the cricetid rodents Calomys sp., Akodon molinae and Eligmodontia typus, followed by other 8 species of rodents, one species of marsupial and undetermined birds and anuran amphibians. For comparing the diets from a relatively undisturbed forested area (Parque Luro and a deforested site, two subcollections of pellets were analyzed. Differences in FNB values and in the prevalence and composition of prey assemblages were observed between these areas. Riassunto Mammiferi predati dal Barbagianni (Tyto alba nella Riserva Parque Luro, La Pampa, Argentina - La dieta del Barbagianni (Tyto alba è stata studiata attraverso l'analisi delle borre ottenute in varie località all'interno della riserva Parque Luro, situata in un'area con boschi xerofili a Prosopis caldenia. Lo studio di 1241 campioni ha rivelato un'elevata prevalenza di roditori cricetidi Calomys sp., Akodon molinae and Eligmodontia typus, seguiti da altre 8 specie di roditori, una specie di marsupiali e uccelli e anfibi anuri indeterminati. Per il confronto delle diete sono state analizzate due sub-raccolte di borre di rapaci provenienti da un'area boscata relativamente indisturbata e da un sito disboscato. In queste aree sono state osservate differenze nei valori della FNB e nella prevalenza e composizione delle prede.

  3. Longevity and lifetime reproductive success of barn swallow offspring are predicted by their hatching date and phenotypic quality.

    Science.gov (United States)

    Saino, Nicola; Romano, Maria; Ambrosini, Roberto; Rubolini, Diego; Boncoraglio, Giuseppe; Caprioli, Manuela; Romano, Andrea

    2012-09-01

    1. Longevity is a major determinant of individual differences in Darwinian fitness. Several studies have analyzed the stochastic, time-dependent causes of variation in longevity, but little information exists from free-ranging animal populations on the effects that environmental conditions and phenotype early in ontogeny have on duration of life. 2. In this long-term (1993-2011) study of a migratory, colonial, passerine bird, the barn swallow (Hirundo rustica), we analyzed longevity and, in a subsample of individuals, lifetime reproductive success (LRS) of the offspring that reached sexual maturity in relation to hatching date, which can affect the rearing environment through a seasonal deterioration in ecological conditions. Moreover, we analyzed the consequences of variation in body size and, for the first time in any species, of a major component of immunity on longevity, both by looking at absolute phenotypic values and at deviations from the brood mean. 3. Accelerated failure time models showed that individuals of both sexes that hatched early in any breeding season enjoyed larger longevity and larger LRS, indicating directional selection for early breeding. Both male and female offspring with large T cell-mediated immune response relative to their siblings and female nestlings that dominated the brood size/age hierarchy had larger longevity than their siblings of inferior phenotypic quality/age. Conversely, absolute phenotypic values did not predict longevity. 4. Frailty modelling disclosed marked spatial heterogeneity in longevity among colonies of origin, again stressing the impact of rearing conditions on longevity. 5. This study therefore reinforces the notion that perinatal environment and maternal decisions over timing and site of breeding, and position in the brood hierarchy can have marked effects on progeny life history that extend well into adulthood. In addition, it provides the first evidence from any bird population in the wild that immune

  4. Turning points in reactor design

    Energy Technology Data Exchange (ETDEWEB)

    Beckjord, E.S.

    1995-09-01

    This article provides some historical aspects on nuclear reactor design, beginning with PWR development for Naval Propulsion and the first commercial application at Yankee Rowe. Five turning points in reactor design and some safety problems associated with them are reviewed: (1) stability of Dresden-1, (2) ECCS, (3) PRA, (4) TMI-2, and (5) advanced passive LWR designs. While the emphasis is on the thermal-hydraulic aspects, the discussion is also about reactor systems.

  5. Fast reactor programme in India

    Indian Academy of Sciences (India)

    P Chellapandi; P R Vasudeva Rao; Prabhat Kumar

    2015-09-01

    Role of fast breeder reactor (FBR) in the Indian context has been discussed with appropriate justification. The FBR programme since 1985 till 2030 is highlighted focussing on the current status and future direction of fast breeder test reactor (FBTR), prototype fast breeder reactor (PFBR) and FBR-1 and 2. Design and technological challenges of PFBR and design and safety targets with means to achieve the same are the major highlights of this paper.

  6. Acceptability of reactors in space

    Energy Technology Data Exchange (ETDEWEB)

    Buden, D.

    1981-04-01

    Reactors are the key to our future expansion into space. However, there has been some confusion in the public as to whether they are a safe and acceptable technology for use in space. The answer to these questions is explored. The US position is that when reactors are the preferred technical choice, that they can be used safely. In fact, it dies not appear that reactors add measurably to the risk associated with the Space Transportation System.

  7. Spiral-shaped disinfection reactors

    KAUST Repository

    Ghaffour, Noreddine

    2015-08-20

    This disclosure includes disinfection reactors and processes for the disinfection of water. Some disinfection reactors include a body that defines an inlet, an outlet, and a spiral flow path between the inlet and the outlet, in which the body is configured to receive water and a disinfectant at the inlet such that the water is exposed to the disinfectant as the water flows through the spiral flow path. Also disclosed are processes for disinfecting water in such disinfection reactors.

  8. Hydrogen Production in Fusion Reactors

    OpenAIRE

    Sudo, S.; Tomita, Y.; Yamaguchi, S.; Iiyoshi, A.; Momota, H; Motojima, O.; Okamoto, M.; Ohnishi, M.; Onozuka, M; Uenosono, C.

    1993-01-01

    As one of methods of innovative energy production in fusion reactors without having a conventional turbine-type generator, an efficient use of radiation produced in a fusion reactor with utilizing semiconductor and supplying clean fuel in a form of hydrogen gas are studied. Taking the candidates of reactors such as a toroidal system and an open system for application of the new concepts, the expected efficiency and a concept of plant system are investigated.

  9. The cervical spine of the American barn owl (Tyto furcata pratincola: I. Anatomy of the vertebrae and regionalization in their S-shaped arrangement.

    Directory of Open Access Journals (Sweden)

    Markus Krings

    Full Text Available BACKGROUND: Owls possess an extraordinary neck and head mobility. To understand this mobility it is necessary to have an anatomical description of cervical vertebrae with an emphasis on those criteria that are relevant for head positioning. No functional description specific to owls is available. METHODOLOGY/PRINCIPAL FINDINGS: X-ray films and micro-CT scans were recorded from American barn owls (Tyto furcata pratincola and used to obtain three-dimensional head movements and three-dimensional models of the 14 cervical vertebrae (C1-C14. The diameter of the vertebral canal, the zygapophyseal protrusion, the distance between joint centers, and the pitching angle were quantified. Whereas the first two variables are purely osteological characteristics of single vertebrae, the latter two take into account interactions between vertebrae. These variables change in characteristic ways from cranial to caudal. The vertebral canal is wide in the cranial and caudal neck regions, but narrow in the middle, where both the zygapophyseal protrusion and the distance between joint centers are large. Pitching angles are more negative in the cranial and caudal neck regions than in the middle region. Cluster analysis suggested a complex regionalization. Whereas the borders (C1 and C13/C14 formed stable clusters, the other cervical vertebrae were sorted into 4 or 5 additional clusters. The borders of the clusters were influenced by the variables analyzed. CONCLUSIONS/SIGNIFICANCE: A statistical analysis was used to evaluate the regionalization of the cervical spine in the barn owl. While earlier measurements have shown that there appear to be three regions of flexibility of the neck, our indicators suggest 3-7 regions. These many regions allow a high degree of flexibility, potentially facilitating the large head turns that barn owls are able to make. The cervical vertebral series of other species should also be investigated using statistical criteria to further

  10. Research on Improving the Capacity of Bulk Curing Barn%提高密集烤房烤能的研究

    Institute of Scientific and Technical Information of China (English)

    刘卫华; 董世峰; 宋子峰; 邱军; 肖鹏; 牛柱峰; 杨宏伟; 刘洪杰

    2011-01-01

    为提高密集烤房产能,达到减工降本、提高烘烤质量、增加烟农效益的目标,对10座3层密集烤房进行了"3改4"处理。结果表明,改造后同等大小的烤房装烟容量同比提高23.5%,烤能比改造前提高30%,干烟成本由改造前的1.94元/kg降至1.76元/kg,节能效果较为可观。烘烤时间增加了24 h,有力地促进了烟叶的后熟,提高了烟叶的品质,单位产量虽略有下降,但上等烟及中上等烟的比例均有较大提高,产值比改造前提高3.8%。%To improve the capacity of bulk curing barn and baking quality, we turned three-floor into four-floor bulk curing barns, which could cut down the cost and energy consumption. The results showed that, the capacity was 23.5% higher than before, the weight of flue-cured tobacco of one barn was 30% heavier than before. In terms of energy consumption, the cost of dry tobacco fell from 1.94 yuan/kg to 1.76 yuan/kg. Baking time extended,which promoted tobacco after-ripening, and improved the quality of tobacco. Though the output was less than before, the proportion of upper class and the mid-upper class, tobacco increased, Interest increased by 3.8%.

  11. 采运烤一体化烤房挂筐式烘烤烟叶的效应%Effects of Tobacco Harvesting Roast Integration Barn Basket Baking

    Institute of Scientific and Technical Information of China (English)

    刘久羽; 阚宏伟; 胡向丹; 张大斌; 孙建生; 邓泳; 张纪利

    2014-01-01

    In order to simplify the baking process of tobacco and reduce tobacco baking cost,the current widespread use of tobacco baking bulk curing barn was transformed and the tobacco harvesting roast basket type curing effect of hanging barn integration was studied in this paper.The results showed that logging roast integration barn basket baking could promote the transformation of tobacco inclusions and aroma precursors,promote the coordination of chemical composition,increase the content of neutral aroma substances and improve the proportion of high class leaf.it could save labor quantity 8.45,reduce baked cost 659.01 Yuan when baked fresh tobacco 4000 kg,and net income increased 939.01 Yuan each 600 kg dry tobacco.%为简化烟叶烘烤工作环节和降低烟叶烘烤成本,利用目前烟叶烘烤普遍使用的密集烤房进行改造,研究了烟叶采运烤一体化烤房的挂筐式烘烤效应。结果表明:采运烤一体化烤房挂筐式烘烤能够促进烟叶内含物和香气前体物质的转化,促进化学成分的协调性及中性香气物质的含量,提高上等烟叶比例。采烤4000 kg 鲜烟可节约用工数量8.45个,烟叶采烤成本降低659.01元;烤后干烟叶(600 kg)纯收入增加939.01元。

  12. Neutrino Oscillation Studies with Reactors

    CERN Document Server

    Vogel, Petr; Zhang, Chao

    2015-01-01

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective, and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavors are quantum mechanical mixtures. Over the past several decades reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle $\\theta_{13}$. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

  13. Remaining Sites Verification Package for the 132-F-1, 141-F Chronic Feeding Sheep Barn, Waste Site Reclassification Form 2006-029

    Energy Technology Data Exchange (ETDEWEB)

    L. M. Dittmer

    2006-08-23

    The 132-F-1 site is the former location of the 141-F Chronic Feeding Sheep Barn that was part of the experimental animal farm at the 100-F Area. It was an L-shaped concrete block building with a concrete floor and concrete animal pens located both inside and outside the building. The 141-F Building was demolished in 1977 following relocation of animal research to the 300 Area. The results of verification sampling demonstrated that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also showed that residual contaminant concentrations are protective of groundwater and the Columbia River.

  14. FAST NEUTRONIC REACTOR

    Science.gov (United States)

    Snell, A.H.

    1957-12-01

    This patent relates to a reactor and process for carrying out a controlled fast neutron chain reaction. A cubical reactive mass, weighing at least 920 metric tons, of uranium metal containing predominantly U/sup 238/ and having a U/sup 235/ content of at least 7.63% is assembled and the maximum neutron reproduction ratio is limited to not substantially over 1.01 by insertion and removal of a varying amount of boron, the reactive mass being substantially freed of moderator.

  15. Biparticle fluidized bed reactor

    Science.gov (United States)

    Scott, C.D.

    1993-12-14

    A fluidized bed reactor system which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase is described. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves. 3 figures.

  16. Licensed reactor nuclear safety criteria applicable to DOE reactors

    Energy Technology Data Exchange (ETDEWEB)

    1991-04-01

    The Department of Energy (DOE) Order DOE 5480.6, Safety of Department of Energy-Owned Nuclear Reactors, establishes reactor safety requirements to assure that reactors are sited, designed, constructed, modified, operated, maintained, and decommissioned in a manner that adequately protects health and safety and is in accordance with uniform standards, guides, and codes which are consistent with those applied to comparable licensed reactors. This document identifies nuclear safety criteria applied to NRC (Nuclear Regulatory Commission) licensed reactors. The titles of the chapters and sections of USNRC Regulatory Guide 1.70, Standard Format and Content of Safety Analysis Reports for Nuclear Power Plants, Rev. 3, are used as the format for compiling the NRC criteria applied to the various areas of nuclear safety addressed in a safety analysis report for a nuclear reactor. In each section the criteria are compiled in four groups: (1) Code of Federal Regulations, (2) US NRC Regulatory Guides, SRP Branch Technical Positions and Appendices, (3) Codes and Standards, and (4) Supplemental Information. The degree of application of these criteria to a DOE-owned reactor, consistent with their application to comparable licensed reactors, must be determined by the DOE and DOE contractor.

  17. 密集烤房在烤烟生产中的优势及效益分析%Advantage and Benefit Analysis of Bulk Curing Barn in Production of Flue-cured Tobacco

    Institute of Scientific and Technical Information of China (English)

    罗元雄; 蔡坤伦; 龚德勇

    2012-01-01

    The article introduces the baking technologies and main operating points of bulk curing barn in the production of flue -cured tobacco. The bulk curing barn possesses the advantages of less labor cost, lower energy consumption, better quality, higher economic benefit and so on. The author puts forward the following suggestions: expediting the construction of bulk curing barn in Anlong county of Guizhou province, enhancing the study on the curing technologies of tobacco leaf, and gradually completing the operational mode of tobacco leaf specialization baking.%介绍了密集式烤房的烘烤工艺、操作要点比较优势和应用效益,提出了加快贵州安龙县密集烤房建设,加大对烟叶烘烤的技术工艺研究,逐步完善烟叶专业化烘烤运行模式的建议.

  18. Reactor Physics Analysis Models for a CANDU Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hang Bok

    2007-10-15

    Canada deuterium uranium (CANDU) reactor physics analysis is typically performed in three steps. At first, macroscopic cross-sections of the reference lattice is produced by modeling the reference fuel channel. Secondly macroscopic cross-sections of reactivity devices in the reactor are generated. The macroscopic cross-sections of a reactivity device are calculated as incremental cross-sections by subtracting macroscopic cross-sections of a three-dimensional lattice without reactivity device from those of a three-dimensional lattice with a reactivity device. Using the macroscopic cross-sections of the reference lattice and incremental cross-sections of the reactivity devices, reactor physics calculations are performed. This report summarizes input data of typical CANDU reactor physics codes, which can be utilized for the future CANDU reactor physics analysis.

  19. Brookhaven leak reactor to close

    CERN Multimedia

    MacIlwain, C

    1999-01-01

    The DOE has announced that the High Flux Beam Reactor at Brookhaven is to close for good. Though the news was not unexpected researchers were angry the decision had been taken before the review to assess the impact of reopening the reactor had been concluded (1 page).

  20. Thermochemical reactor systems and methods

    Energy Technology Data Exchange (ETDEWEB)

    Lipinski, Wojciech; Davidson, Jane Holloway; Chase, Thomas Richard

    2016-11-29

    Thermochemical reactor systems that may be used to produce a fuel, and methods of using the thermochemical reactor systems, utilizing a reactive cylindrical element, an optional energy transfer cylindrical element, an inlet gas management system, and an outlet gas management system.

  1. Chemical-vapor-deposition reactor

    Science.gov (United States)

    Chern, S.

    1979-01-01

    Reactor utilizes multiple stacked trays compactly arranged in paths of horizontally channeled reactant gas streams. Design allows faster and more efficient deposits of film on substrates, and reduces gas and energy consumption. Lack of dead spots that trap reactive gases reduces reactor purge time.

  2. Antineutrino Monitoring of Thorium Reactors

    CERN Document Server

    Akindele, Oluwatomi A; Norman, Eric B

    2015-01-01

    Various groups have demonstrated that antineutrino monitoring can be successful in assessing the plutonium content in water-cooled nuclear reactors for nonproliferation applications. New reactor designs and concepts incorporate nontraditional fuels types and chemistry. Understanding how these properties affect the antineutrino emission from a reactor can extend the applicability of antineutrino monitoring.Thorium molten salt reactors (MSR) breed U-233, that if diverted constitute an IAEA direct use material. The antineutrino spectrum from the fission of U-233 has been determined, the feasibility of detecting the diversion of a significant quantity, 8 kg of U-233, within the IAEA timeliness goal of 30 days has been evaluated. The antineutrino emission from a thorium reactor operating under normal conditions is compared to a diversion scenario at a 25 meter standoff by evaluating the daily antineutrino count rate and the energy spectrum of the detected antineutrinos. It was found that the diversion of a signifi...

  3. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    Vivek V Ranade

    2014-03-01

    Catalytic reactions are ubiquitous in chemical and allied industries. A homogeneous or heterogeneous catalyst which provides an alternative route of reaction with lower activation energy and better control on selectivity can make substantial impact on process viability and economics. Extensive studies have been conducted to establish sound basis for design and engineering of reactors for practising such catalytic reactions and for realizing improvements in reactor performance. In this article, application of recent (and not so recent) developments in engineering reactors for catalytic reactions is discussed. Some examples where performance enhancement was realized by catalyst design, appropriate choice of reactor, better injection and dispersion strategies and recent advances in process intensification/ multifunctional reactors are discussed to illustrate the approach.

  4. Unsteady processes in catalytic reactors

    Energy Technology Data Exchange (ETDEWEB)

    Matros, Yu.Sh.

    1985-01-01

    In recent years a realization has occurred that reaction and reactor dynamics must be considered when designing and operating catalytic reactors. In this book, the author has focussed on both the processes occurring on individual porous-catalyst particles as well as the phenomena displayed by collections of these particles in fixed-bed reactors. The major topics discussed include the effects of unsteady-state heat and mass transfer, the influence of inhomogeneities and stagnant regions in fixed beds, and reactor operation during forced cycling of operating conditions. Despite the title of the book, attention is also paid to the determination of the number and stability of fixed-bed steady states, with the aim of describing the possibility of controlling reactors at unstable steady states. However, this development is somewhat dated, given the recent literature on multiplicity phenomena and process control.

  5. A model of reactor kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, A.S.; Thompson, B.R.

    1988-09-01

    The analytical model of nuclear reactor transients, incorporating both mechanical and nuclear effects, simulates reactor kinetics. Linear analysis shows the stability borderline for small power perturbations. In a stable system, initial power disturbances die out with time. With an unstable combination of nuclear and mechanical characteristics, initial disturbances persist and may increase with time. With large instability, oscillations of great magnitude occur. Stability requirements set limits on the power density at which particular reactors can operate. The limiting power density depends largely on the product of two terms: the fraction of delayed neutrons and the frictional damping of vibratory motion in reactor core components. As the fraction of delayed neutrons is essentially fixed, mechanical damping largely determines the maximum power density. A computer program, based on the analytical model, calculates and plots reactor power as a nonlinear function of time in response to assigned values of mechanical and nuclear characteristics.

  6. Metallic fuels for advanced reactors

    Science.gov (United States)

    Carmack, W. J.; Porter, D. L.; Chang, Y. I.; Hayes, S. L.; Meyer, M. K.; Burkes, D. E.; Lee, C. B.; Mizuno, T.; Delage, F.; Somers, J.

    2009-07-01

    In the framework of the Generation IV Sodium Fast Reactor Program, the Advanced Fuel Project has conducted an evaluation of the available fuel systems supporting future sodium cooled fast reactors. This paper presents an evaluation of metallic alloy fuels. Early US fast reactor developers originally favored metal alloy fuel due to its high fissile density and compatibility with sodium. The goal of fast reactor fuel development programs is to develop and qualify a nuclear fuel system that performs all of the functions of a conventional fast spectrum nuclear fuel while destroying recycled actinides. This will provide a mechanism for closure of the nuclear fuel cycle. Metal fuels are candidates for this application, based on documented performance of metallic fast reactor fuels and the early results of tests currently being conducted in US and international transmutation fuel development programs.

  7. A percepção de valor dos ativos entre o mundo real e o virtual: o caso Barnes and Noble

    Directory of Open Access Journals (Sweden)

    Dalton Schmitt Jr

    2002-01-01

    Full Text Available Uma das questões de grande debate no mercado de investimentos gira em torno da diferença entre a valorização e a volatilidade de ativos relacionados a empresas do mundo real e empresas do mundo virtual (nova economia. O maior fluxo as informações, a incerteza e a inexistência de um modelo de negócio vencedor na nova economia têm ampliado essa discussão ao longo dos anos. O presente artigo tem como objetivo analisar a valorização de ativos de empresas desses dois mundos (real e virtual de mesmo foco de negócio e voltadas ao mesmo mercado em relação aos seus principais índices financeiros e performance. Estar-se-ão analisando dois negócios com mesmo fim de mercado mas que, por estarem com posicionamentos diferentes, apresentam características diferenciadas no que se refere a valorização de mercado e performance financeira. Visando desenvolver tal objetivo, o artigo analisará as empresa Barnes & Noble, tradicional varejista do segmento de livros no mercado norte-americano, e a sua subsidiária Barnes & Noble.com.

  8. Improvement of Drying Temperature Control Method in Tobacco-Flue-Cured Barn%烤烟烘烤房干温度控制方法的改进

    Institute of Scientific and Technical Information of China (English)

    李英俊; 金珖龙

    2011-01-01

    为了提高烤烟烘烤房的干温度精度和烤烟的烘烤质量,降低耗煤量,对往复推动式烟叶烘烤仪的干温度的控制方法进行了改进.通过利用模糊控制技术控制推煤电动机工作时间和停止工作时间,实现了根据烘烤工艺的要求对烤烟烘烤房的干温度进行实时监测的精确控制目标.%To improve the precision of drying temperature control of tobacco-flue-cured barn and the quality of flue-cured tobacco,and to reduce coal consumption for flue-cured tobacco,the drying temperature control method for the flue-cured tobacco apparatus with reciprocating transport function was improved.The working time and halting time of a coal-transport electric motor were controlled by fuzzy control technology,with the technology above the real-time of the accuracy control of the drying temperature of tobacco flue-cured barn was realized.

  9. Neutrino Experiments at Reactors

    Science.gov (United States)

    Reines, F.; Gurr, H. S.; Jenkins, T. L.; Munsee, J. H.

    1968-09-09

    A description is given of the electron-antineutrino program using a large fission reactor. A search has been made for a neutral weak interaction via the reaction (electron antineutrino + d .> p + n + electron antineutrino), the reaction (electron antineutrino + d .> n + n + e{sup +}) has now been detected, and an effort is underway to observe the elastic scattering reaction (electron antineutrino + e{sup -} .> electron antineutrino + e{sup -}) as well as to measure more precisely the reaction (electron antineutrino + p .> n + e{sup+}). The upper limit on the elastic scattering reaction which we have obtained with our large composite NaI, plastic, liquid scintillation detector is now about 50 times the predicted value.

  10. Neutronic Reactor Shield

    Science.gov (United States)

    Fermi, Enrico; Zinn, Walter H.

    The argument of the present Patent is a radiation shield suitable for protection of personnel from both gamma rays and neutrons. Such a shield from dangerous radiations is achieved to the best by the combined action of a neutron slowing material (a moderator) and a neutron absorbing material. Hydrogen is particularly effective for this shield since it is a good absorber of slow neutrons and a good moderator of fast neutrons. The neutrons slowed down by hydrogen may, then, be absorbed by other materials such as boron, cadmium, gadolinium, samarium or steel. Steel is particularly convenient for the purpose, given its effectiveness in absorbing also the gamma rays from the reactor (both primary gamma rays and secondary ones produced by the moderation of neutrons). In particular, in the present Patent a shield is described, made of alternate layers of steel and Masonite (an hydrolized ligno-cellulose material). The object of the present Patent is not discussed in any other published paper.

  11. Licensed reactor nuclear safety criteria applicable to DOE reactors

    Energy Technology Data Exchange (ETDEWEB)

    1993-11-01

    This document is a compilation and source list of nuclear safety criteria that the Nuclear Regulatory Commission (NRC) applies to licensed reactors; it can be used by DOE and DOE contractors to identify NRC criteria to be evaluated for application to the DOE reactors under their cognizance. The criteria listed are those that are applied to the areas of nuclear safety addressed in the safety analysis report of a licensed reactor. They are derived from federal regulations, USNRC regulatory guides, Standard Review Plan (SRP) branch technical positions and appendices, and industry codes and standards.

  12. Barn og bovaryst imellem

    DEFF Research Database (Denmark)

    Mogensen, Tine Engel

    2008-01-01

    Om Bovarysme-tematikken i Kjærlighet. Romanen skriver sig ind i en lang tradition for kritik af romancegenren (og ikke mindst dét, denne 'gør ved' sine læsere). Ud over Don Quixote/Madame Bovary inddrages en forholdsvis ukendt roman af Zola, Une page d'amour, som lægger sig i forlængelse af Madame...

  13. Reactor service life extension program

    Energy Technology Data Exchange (ETDEWEB)

    Caskey, G.R.; Sindelar, R.L.; Ondrejcin, R.S.; Baumann, E.W.

    1990-12-31

    A review of the Savannah River Site production reactor systems was initiated in 1980 and led to implementation of the Reactor Materials Program in 1984 to assess reactor safety and reactor service life. The program evaluated performance of the reactor tanks, primary coolant piping, and thermal shields, components of welded construction that were fabricated from Type 304 stainless steel. The structural integrity analysis of the primary coolant system has shown that the pressure boundary is not susceptible to gross rupture, including a double ended guillotine break or equivalent large area bank. Residual service life is potentially limited by two material degradation modes, irradiation damage and intergranular stress corrosion cracking. Analysis of the structural integrity of the tanks and piping has shown that continued safe operation of the reactors for several additional decades is not limited by the material performance of the primary coolant system. Although irradiation damage has not degraded material behavior to an unacceptable level, past experience has revealed serious difficulties with repair welding on irradiated stainless steel. Stress corrosion can be mitigated by newly identified limits on impurity concentrations in the coolant water and by stress mitigation of weld residual stresses. Work continues in several areas: the effects of helium on mechanical behavior of irradiated stainless steel; improved weld methods for piping and the reactor tanks; and a surveillance program to track irradiation effects on the tank walls.

  14. Reactor service life extension program

    Energy Technology Data Exchange (ETDEWEB)

    Caskey, G.R.; Sindelar, R.L.; Ondrejcin, R.S.; Baumann, E.W.

    1990-01-01

    A review of the Savannah River Site production reactor systems was initiated in 1980 and led to implementation of the Reactor Materials Program in 1984 to assess reactor safety and reactor service life. The program evaluated performance of the reactor tanks, primary coolant piping, and thermal shields, components of welded construction that were fabricated from Type 304 stainless steel. The structural integrity analysis of the primary coolant system has shown that the pressure boundary is not susceptible to gross rupture, including a double ended guillotine break or equivalent large area bank. Residual service life is potentially limited by two material degradation modes, irradiation damage and intergranular stress corrosion cracking. Analysis of the structural integrity of the tanks and piping has shown that continued safe operation of the reactors for several additional decades is not limited by the material performance of the primary coolant system. Although irradiation damage has not degraded material behavior to an unacceptable level, past experience has revealed serious difficulties with repair welding on irradiated stainless steel. Stress corrosion can be mitigated by newly identified limits on impurity concentrations in the coolant water and by stress mitigation of weld residual stresses. Work continues in several areas: the effects of helium on mechanical behavior of irradiated stainless steel; improved weld methods for piping and the reactor tanks; and a surveillance program to track irradiation effects on the tank walls.

  15. Assessment of torsatrons as reactors

    Energy Technology Data Exchange (ETDEWEB)

    Lyon, J.F. (Oak Ridge National Lab., TN (United States)); Painter, S.L. (Australian National Univ., Canberra, ACT (Australia))

    1992-12-01

    Stellarators have significant operational advantages over tokamaks as ignited steady-state reactors because stellarators have no dangerous disruptions and no need for continuous current drive or power recirculated to the plasma, both easing the first wall, blanket, and shield design; less severe constraints on the plasma parameters and profiles; and better access for maintenance. This study shows that a reactor based on the torsatron configuration (a stellarator variant) could also have up to double the mass utilization efficiency (MUE) and a significantly lower cost of electricity (COE) than a conventional tokamak reactor (ARIES-I) for a range of assumptions. Torsatron reactors can have much smaller coil systems than tokamak reactors because the coils are closer to the plasma and they have a smaller cross section (higher average current density because of the lower magnetic field). The reactor optimization approach and the costing and component models are those used in the current stage of the ARIES-I tokamak reactor study. Typical reactor parameters for a 1-GW(e) Compact Torsatron reactor example are major radius R[sub 0] = 6.6-8.8 m, on-axis magnetic field B[sup 0] = 4.8-7.5 T, B[sub max] (on coils) = 16 T, MUE 140-210 kW(e)/tonne, and COE (in constant 1990 dollars) = 67-79 mill/kW(e)h. The results are relatively sensitive to assumptions on the level of confinement improvement and the blanket thickness under the inboard half of the helical windings but relatively insensitive to other assumptions.

  16. Concept for LEU Burst Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Steven Karl [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kimpland, Robert Herbert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-07

    Design and performance of a proposed LEU burst reactor are sketched. Salient conclusions reached are the following: size would be ~1,500 kg or greater, depending on the size of the central cavity; internal stresses during burst require split rings for relief; the reactor would likely require multiple control and safety rods for fine control; the energy spectrum would be comparable to that of HEU machines; and burst yields and steady-state power levels will be significantly greater in an LEU reactor.

  17. Nuclear reactor downcomer flow deflector

    Energy Technology Data Exchange (ETDEWEB)

    Gilmore, Charles B. (Greensburg, PA); Altman, David A. (Pittsburgh, PA); Singleton, Norman R. (Murrysville, PA)

    2011-02-15

    A nuclear reactor having a coolant flow deflector secured to a reactor core barrel in line with a coolant inlet nozzle. The flow deflector redirects incoming coolant down an annulus between the core barrel and the reactor vessel. The deflector has a main body with a front side facing the fluid inlet nozzle and a rear side facing the core barrel. The rear side of the main body has at least one protrusion secured to the core barrel so that a gap exists between the rear side of the main body adjacent the protrusion and the core barrel. Preferably, the protrusion is a relief that circumscribes the rear side of the main body.

  18. Safety of VVER-440 reactors

    CERN Document Server

    Slugen, Vladimir

    2011-01-01

    Safety of VVER-440 Reactors endeavours to promote an increase in the safety of VVER-440 nuclear reactors via the improvement of fission products limitation systems and the implementation of special non-destructive spectroscopic methods for materials testing. All theoretical and experimental studies performed the by author over the last 25 years have been undertaken with the aim of improving VVER-440 defence in depth, which is one of the most important principle for ensuring safety in nuclear power plants. Safety of VVER-440 Reactors is focused on the barrier system through which the safety pri

  19. Random processes in nuclear reactors

    CERN Document Server

    Williams, M M R

    1974-01-01

    Random Processes in Nuclear Reactors describes the problems that a nuclear engineer may meet which involve random fluctuations and sets out in detail how they may be interpreted in terms of various models of the reactor system. Chapters set out to discuss topics on the origins of random processes and sources; the general technique to zero-power problems and bring out the basic effect of fission, and fluctuations in the lifetime of neutrons, on the measured response; the interpretation of power reactor noise; and associated problems connected with mechanical, hydraulic and thermal noise sources

  20. Fuel Fabrication and Nuclear Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Karpius, Peter Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-02

    The uranium from the enrichment plant is still in the form of UF6. UF6 is not suitable for use in a reactor due to its highly corrosive chemistry as well as its phase diagram. UF6 is converted into UO2 fuel pellets, which are in turn placed in fuel rods and assemblies. Reactor designs are variable in moderators, coolants, fuel, performance etc.The dream of energy ‘too-cheap to meter’ is no more, and now the nuclear power industry is pushing ahead with advanced reactor designs.

  1. Nuclear reactor PBMR and cogeneration; Reactor nuclear PBMR y cogeneracion

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez S, J. R.; Alonso V, G., E-mail: ramon.ramirez@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2013-10-15

    In recent years the nuclear reactor designs for the electricity generation have increased their costs, so that at the moment costs are managed of around the 5000 US D for installed kw, reason for which a big nuclear plant requires of investments of the order of billions of dollars, the designed reactors as modular of low power seek to lighten the initial investment of a big reactor dividing the power in parts and dividing in modules the components to lower the production costs, this way it can begin to build a module and finished this to build other, differing the long term investment, getting less risk therefore in the investment. On the other hand the reactors of low power can be very useful in regions where is difficult to have access to the electric net being able to take advantage of the thermal energy of the reactor to feed other processes like the water desalination or the vapor generation for the processes industry like the petrochemical, or even more the possible hydrogen production to be used as fuel. In this work the possibility to generate vapor of high quality for the petrochemical industry is described using a spheres bed reactor of high temperature. (Author)

  2. FASTER test reactor preconceptual design report summary

    Energy Technology Data Exchange (ETDEWEB)

    Grandy, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Belch, H. [Argonne National Lab. (ANL), Argonne, IL (United States); Brunett, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Heidet, F. [Argonne National Lab. (ANL), Argonne, IL (United States); Hill, R. [Argonne National Lab. (ANL), Argonne, IL (United States); Hoffman, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Jin, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Mohamed, W. [Argonne National Lab. (ANL), Argonne, IL (United States); Moisseytsev, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Passerini, S. [Argonne National Lab. (ANL), Argonne, IL (United States); Sienicki, J. [Argonne National Lab. (ANL), Argonne, IL (United States); Sumner, T. [Argonne National Lab. (ANL), Argonne, IL (United States); Vilim, R. [Argonne National Lab. (ANL), Argonne, IL (United States); Hayes, Steven [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-02-29

    The FASTER reactor plant is a sodium-cooled fast spectrum test reactor that provides high levels of fast and thermal neutron flux for scientific research and development. The 120MWe FASTER reactor plant has a superheated steam power conversion system which provides electrical power to a local grid allowing for recovery of operating costs for the reactor plant.

  3. ADAPTIVE CONTROL SYSTEM OF INDUSTRIAL REACTORS

    Directory of Open Access Journals (Sweden)

    Vyacheslav K. Mayevski

    2014-01-01

    Full Text Available This paper describes a mathematical model of an industrial chemical reactor for production of synthetic rubber. During reactor operation the model parameters vary considerably. To create a control algorithm performed transformation of mathematical model of the reactor in order to obtain a dependency that can be used to determine the model parameters are changing during reactor operation.

  4. FASTER Test Reactor Preconceptual Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Grandy, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Belch, H. [Argonne National Lab. (ANL), Argonne, IL (United States); Brunett, A. J. [Argonne National Lab. (ANL), Argonne, IL (United States); Heidet, F. [Argonne National Lab. (ANL), Argonne, IL (United States); Hill, R. [Argonne National Lab. (ANL), Argonne, IL (United States); Hoffman, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Jin, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Mohamed, W. [Argonne National Lab. (ANL), Argonne, IL (United States); Moisseytsev, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Passerini, S. [Argonne National Lab. (ANL), Argonne, IL (United States); Sienicki, J. [Argonne National Lab. (ANL), Argonne, IL (United States); Sumner, T. [Argonne National Lab. (ANL), Argonne, IL (United States); Vilim, R. [Argonne National Lab. (ANL), Argonne, IL (United States); Hayes, S. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-03-31

    The FASTER test reactor plant is a sodium-cooled fast spectrum test reactor that provides high levels of fast and thermal neutron flux for scientific research and development. The 120MWe FASTER reactor plant has a superheated steam power conversion system which provides electrical power to a local grid allowing for recovery of operating costs for the reactor plant.

  5. Breeder Reactors, Understanding the Atom Series.

    Science.gov (United States)

    Mitchell, Walter, III; Turner, Stanley E.

    The theory of breeder reactors in relationship to a discussion of fission is presented. Different kinds of reactors are characterized by the cooling fluids used, such as liquid metal, gas, and molten salt. The historical development of breeder reactors over the past twenty-five years includes specific examples of reactors. The location and a brief…

  6. Evolution of the tandem mirror reactor concept

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, G.A.; Logan, B.G.

    1982-03-09

    We discuss the evolution of the tandem mirror reactor concept from the original conceptual reactor design (1977) through the first application of the thermal barrier concept to a reactor design (1979) to the beginning of the Mirror Advanced Reactor Study (1982).

  7. 空气热-煤混合能源烤房在烟叶烘烤中的应用效果%Application Effect of Air Heat-Coal Mixed Energy Barn in Tobacco Flue-curing

    Institute of Scientific and Technical Information of China (English)

    谢云波; 罗定棋; 张永辉; 谢强; 雷晓; 何余勇; 张溢; 杜纯青

    2012-01-01

    为空气热-煤混合能源烤房在烤烟生产上的推广应用提供科学依据,进行了空气热-煤混合能源烤房与普通燃煤烤房对考后烟叶质量及经济效益的对比试验.结果表明:空气热-煤混合能源烤房的最佳经济结合点为50℃转火,即在50℃前用热泵加热,达到50℃后改用煤炉加热.与普通燃煤烤房相比,空气热-煤混合能源烤房可以节约能源资源消耗46.8%;每烤房单次节省烘烤费用128.9元,节省率20.7%;烤后烟叶上等烟比例较高,低次等烟比例很低,烟叶外观质量最佳,农民销售收入增加28.4%;烤房耗煤量低,产生的粉尘和大气污染物排放量减少57.8%.%To provide a scientific basis for air heat-coal mixed energy barn popularization and application in the production of flue-cured tobacco, a contrast test of flue-cured tobacco quality and economic benefits was conducted between air heat-coal mixed energy barn and ordinary coal-fired barn. The results showed that it was best to heat the barn using heat pump before 50℃ and then using coal stove. Compared with ordinary coal-fired barn, air heat-coal mixed energy barn could save energy and resources consumption by 46. 8%; Saved per barn baking costs 128. 9 Yuan(saving rate 20.7%); High-class flue-cured tobacco accounted for a higher proportion while low-class flue-cured tobacco accounted for a low proportion, the appearance quality was the best and peasants' incomes were enhanced by 28. 4%; the dust and air pollutant emissions was reduced by 57. 8% as the coal consumption decreased.

  8. Jules Horowitz Reactor, basic design

    Energy Technology Data Exchange (ETDEWEB)

    Bergamaschi, Y.; Bouilloux, Y.; Chantoin, P.; Guigon, B.; Bravo, X.; Germain, C.; Rommens, M.; Tremodeux, P

    2003-07-01

    Since the shutdown of the SILOE reactor in 1997, the OSIRIS reactor has ensured the needs regarding technological irradiation at CEA including those of its industrial partners and customers. The Jules Horowitz Reactor will replace it. It has the ambition to provide the necessary nuclear data and maintain a fission research capacity in Europe after 2010. This capacity should be service-oriented. It will be established in Cadarache. The Jules Horowitz reactor will also: - represent a significant step in term of performances and experimental capabilities, - be designed with a high flexibility, in order to satisfy the current demand from European industry, research and be able to accommodate future requirements, - reach a high level of safety, according to the best current practice. This paper will present the main functionalities and the design options resulting from the 'preliminary design' studies. (authors)

  9. Advanced Catalytic Hydrogenation Retrofit Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Reinaldo M. Machado

    2002-08-15

    Industrial hydrogenation is often performed using a slurry catalyst in large stirred-tank reactors. These systems are inherently problematic in a number of areas, including industrial hygiene, process safety, environmental contamination, waste production, process operability and productivity. This program proposed the development of a practical replacement for the slurry catalysts using a novel fixed-bed monolith catalyst reactor, which could be retrofitted onto an existing stirred-tank reactor and would mitigate many of the minitations and problems associated with slurry catalysts. The full retrofit monolith system, consisting of a recirculation pump, gas/liquid ejector and monolith catalyst, is described as a monolith loop reactor or MLR. The MLR technology can reduce waste and increase raw material efficiency, which reduces the overall energy required to produce specialty and fine chemicals.

  10. Advanced Carbothermal Electric Reactor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall objective of the Phase 1 effort was to demonstrate the technical feasibility of the Advanced Carbothermal Electric (ACE) Reactor concept. Unlike...

  11. Reactor operation environmental information document

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, L.R.; Hayes, D.W.; Hunter, C.H.; Marter, W.L.; Moyer, R.A.

    1989-12-01

    This volume is a reactor operation environmental information document for the Savannah River Plant. Topics include meteorology, surface hydrology, transport, environmental impacts, and radiation effects. 48 figs., 56 tabs. (KD)

  12. Unique features of space reactors

    Science.gov (United States)

    Buden, David

    Space reactors are designed to meet a unique set of requirements; they must be sufficiently compact to be launched in a rocket to their operational location, operate for many years without maintenance and servicing, operate in extreme environments, and reject heat by radiation to space. To meet these restrictions, operating temperatures are much greater than in terrestrial power plants, and the reactors tend to have a fast neutron spectrum. Currently, a new generation of space reactor power plants is being developed. The major effort is in the SP-100 program, where the power plant is being designed for seven years of full power, and no maintenance operation at a reactor outlet operating temperature of 1350 K.

  13. Thermal Analysis for Mobile Reactor

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Mobile reactor design in the paper is consisted of two grades of thermal electric conversion. The first grade is the thermionic conversion inside the core and the second grade is thermocouple conversion

  14. Teaching About Nature's Nuclear Reactors

    CERN Document Server

    Herndon, J M

    2005-01-01

    Naturally occurring nuclear reactors existed in uranium deposits on Earth long before Enrico Fermi built the first man-made nuclear reactor beneath Staggs Field in 1942. In the story of their discovery, there are important lessons to be learned about scientific inquiry and scientific discovery. Now, there is evidence to suggest that the Earth's magnetic field and Jupiter's atmospheric turbulence are driven by planetary-scale nuclear reactors. The subject of planetocentric nuclear fission reactors can be a jumping off point for stimulating classroom discussions about the nature and implications of planetary energy sources and about the geomagnetic field. But more importantly, the subject can help to bring into focus the importance of discussing, debating, and challenging current thinking in a variety of areas.

  15. Advanced Carbothermal Electric Reactor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop the Advanced Carbothermal Electric (ACE) reactor to efficiently extract oxygen from lunar regolith. Unlike state-of-the-art carbothermal...

  16. Solid State Reactor Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Mays, G.T.

    2004-03-10

    The Solid State Reactor (SSR) is an advanced reactor concept designed to take advantage of Oak Ridge National Laboratory's (ORNL's) recently developed graphite foam that has enhanced heat transfer characteristics and excellent high-temperature mechanical properties, to provide an inherently safe, self-regulated, source of heat for power and other potential applications. This work was funded by the U.S. Department of Energy's Nuclear Energy Research Initiative (NERI) program (Project No. 99-064) from August 1999 through September 30, 2002. The initial concept of utilizing the graphite foam as a basis for developing an advanced reactor concept envisioned that a suite of reactor configurations and power levels could be developed for several different applications. The initial focus was looking at the reactor as a heat source that was scalable, independent of any heat removal/power conversion process. These applications might include conventional power generation, isotope production and destruction (actinides), and hydrogen production. Having conducted the initial research on the graphite foam and having performed the scoping parametric analyses from neutronics and thermal-hydraulic perspectives, it was necessary to focus on a particular application that would (1) demonstrate the viability of the overall concept and (2) require a reasonably structured design analysis process that would synthesize those important parameters that influence the concept the most as part of a feasible, working reactor system. Thus, the application targeted for this concept was supplying power for remote/harsh environments and a design that was easily deployable, simplistic from an operational standpoint, and utilized the new graphite foam. Specifically, a 500-kW(t) reactor concept was pursued that is naturally load following, inherently safe, optimized via neutronic studies to achieve near-zero reactivity change with burnup, and proliferation resistant. These four major areas

  17. Microchannel Reactors for ISRU Applications

    Science.gov (United States)

    Carranza, Susana; Makel, Darby B.; Blizman, Brandon; Ward, Benjamin J.

    2005-02-01

    Affordable planning and execution of prolonged manned space missions depend upon the utilization of local resources and the waste products which are formed in manned spacecraft and surface bases. Successful in-situ resources utilization (ISRU) will require component technologies which provide optimal size, weight, volume, and power efficiency. Microchannel reactors enable the efficient chemical processing of in situ resources. The reactors can be designed for the processes that generate the most benefit for each mission. For instance, propellants (methane) can be produced from carbon dioxide from the Mars atmosphere using the Sabatier reaction and ethylene can be produced from the partial oxidation of methane. A system that synthesizes ethylene could be the precursor for systems to synthesize ethanol and polyethylene. Ethanol can be used as a nutrient for Astrobiology experiments, as well as the production of nutrients for human crew (e.g. sugars). Polyethylene can be used in the construction of habitats, tools, and replacement parts. This paper will present recent developments in miniature chemical reactors using advanced Micro Electro Mechanical Systems (MEMS) and microchannel technology to support ISRU of Mars and lunar missions. Among other applications, the technology has been demonstrated for the Sabatier process and for the partial oxidation of methane. Microchannel reactors were developed based on ceramic substrates as well as metal substrates. In both types of reactors, multiple layers coated with catalytic material are bonded, forming a monolithic structure. Such reactors are readily scalable with the incorporation of extra layers. In addition, this reactor structure minimizes pressure drop and catalyst settling, which are common problems in conventional packed bed reactors.

  18. Reactor antineutrinos and nuclear physics

    Science.gov (United States)

    Balantekin, A. B.

    2016-11-01

    Short-baseline reactor neutrino experiments successfully measured the neutrino parameters they set out to measure, but they also identified a shape distortion in the 5-7 MeV range as well as a reduction from the predicted value of the flux. Nuclear physics input into the calculations of reactor antineutrino spectra needs to be better refined if this anomaly is to be interpreted as due to sterile neutrino states.

  19. Reactor Simulator Testing

    Science.gov (United States)

    Schoenfeld, Michael P.; Webster, Kenny L.; Pearson, Boise J.

    2013-01-01

    As part of the Nuclear Systems Office Fission Surface Power Technology Demonstration Unit (TDU) project, a reactor simulator test loop (RxSim) was design & built to perform integrated testing of the TDU components. In particular, the objectives of RxSim testing was to verify the operation of the core simulator, the instrumentation and control system, and the ground support gas and vacuum test equipment. In addition, it was decided to include a thermal test of a cold trap purification design and a pump performance test at pump voltages up to 150 V since the targeted mass flow rate of 1.75 kg/s was not obtained in the RxSim at the originally constrained voltage of 120 V. This paper summarizes RxSim testing. The gas and vacuum ground support test equipment performed effectively in NaK fill, loop pressurization, and NaK drain operations. The instrumentation and control system effectively controlled loop temperature and flow rates or pump voltage to targeted settings. The cold trap design was able to obtain the targeted cold temperature of 480 K. An outlet temperature of 636 K was obtained which was lower than the predicted 750 K but 156 K higher than the cold temperature indicating the design provided some heat regeneration. The annular linear induction pump (ALIP) tested was able to produce a maximum flow rate of 1.53 kg/s at 800 K when operated at 150 V and 53 Hz.

  20. Novel Catalytic Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Nemser, PhD

    2010-10-01

    There are many industrial catalytic organic reversible reactions with amines or alcohols that have water as one of the products. Many of these reactions are homogeneously catalyzed. In all cases removal of water facilitates the reaction and produces more of the desired chemical product. By shifting the reaction to right we produce more chemical product with little or no additional capital investment. Many of these reactions can also relate to bioprocesses. Given the large number of water-organic compound separations achievable and the ability of the Compact Membrane Systems, Inc. (CMS) perfluoro membranes to withstand these harsh operating conditions, this is an ideal demonstration system for the water-of-reaction removal using a membrane reactor. Enhanced reaction synthesis is consistent with the DOE objective to lower the energy intensity of U.S. industry 25% by 2017 in accord with the Energy Policy Act of 2005 and to improve the United States manufacturing competitiveness. The objective of this program is to develop the platform technology for enhancing homogeneous catalytic chemical syntheses.

  1. LMFBR type reactor

    Energy Technology Data Exchange (ETDEWEB)

    Iwashige, Kengo

    1996-06-21

    In an LMFBR type reactor, partitions are disposed to a coolant channel at positions lower than the free liquid level, and the width of the partitions is adapted to have a predetermined condition. Namely, when low temperature fluid overflowing the wall of the coolant channel, flows down and collided against the free liquid surface in the coolant channel, since the dropping speed thereof is reduced abruptly, large pressure waves are caused by kinetic force of the low temperature fluid. However, if appropriate numbers of partitions having an appropriate shape are formed, the dropping speed of the low temperature fluid is moderated to reduce the pressure waves. In addition, since the pressure waves are dispersed to the circumferential and lateral directions of the coolant flow channel respectively, the propagation of the pressure waves can be prevented effectively. Further, when the flow of the low temperature fluid is changed to the circumferential direction, for example, by earthquakes, since the partitions act as members resisting against the circumferential change of the low temperature fluid, the change of the direction can be suppressed. (N.H.)

  2. Calculation of reactor antineutrino spectra in TEXONO

    CERN Document Server

    Chen Dong Liang; Mao Ze Pu; Wong, T H

    2002-01-01

    In the low energy reactor antineutrino physics experiments, either for the researches of antineutrino oscillation and antineutrino reactions, or for the measurement of abnormal magnetic moment of antineutrino, the flux and the spectra of reactor antineutrino must be described accurately. The method of calculation of reactor antineutrino spectra was discussed in detail. Furthermore, based on the actual circumstances of NP2 reactors and the arrangement of detectors, the flux and the spectra of reactor antineutrino in TEXONO were worked out

  3. Tritium management in fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Galloway, T.R.

    1978-05-01

    This is a review paper covering the key environmental and safety issues and how they have been handled in the various magnetic and inertial confinement concepts and reference designs. The issues treated include: tritium accident analyses, tritium process control, occupational safety, HTO formation rate from the gas-phase, disposal of tritium contaminated wastes, and environmental impact--each covering the Joint European Tokamak (J.E.T. experiment), Tokamak Fusion Test Reactor (TFTR), Russian T-20, The Next Step (TNS) designs by Westinghouse/ORNL and General Atomic/ANL, the ANL and ORNL EPR's, the G.A. Doublet Demonstration Reactor, the Italian Fintor-D and the ORNL Demo Studies. There are also the following full scale plant reference designs: UWMAK-III, LASL's Theta Pinch Reactor Design (RTPR), Mirror Fusion Reactor (MFR), Tandem Mirror Reactor (TMR), and the Mirror Hybrid Reactor (MHR). There are four laser device breakeven experiments, SHIVA-NOVA, LLL reference designs, ORNL Laser Fusion power plant, the German ''Saturn,'' and LLL's Laser Fusion EPR I and II.

  4. 新疆褐牛舍饲育肥周岁出栏试验%Experiment on Barn Feeding Fattening Off Taking at One Year Old in Xinjiang Brow Calf

    Institute of Scientific and Technical Information of China (English)

    李静; 热西旦·阿不力孜; 乃比江; 艾比拜; 艾力

    2012-01-01

    [目的]本试验旨在研究新疆褐牛舍饲育肥周岁出栏的效果。[方法]选择4~5月龄新疆褐牛20头作为试验对象,随机分为2组,在相同日粮、不同舍饲方式条件下进行日增重、屠宰性能效果对比试验。[结果]表明:舍饲育肥新疆褐牛犊牛有较高日增重和较高屠宰率;不同舍饲方式对新疆褐牛犊牛育肥增重效果差异不显著。[结论]说明舍饲育肥新疆褐牛犊牛具有较好的日增重效果,可进行示范推广。%[Objective]Effect and feasibility was studied of barn feeding fattening off taking at one year old in Xinjiang brow calf . [Method]20 individuals of 4~5 month old xinjiang brow calf were randomly se- lected and divided into two groups. They were fattened under similar ration and different barn feeding con- ditions to compare the effect of daily weight gain and slaughter performance. [Result]The results indicated that the daily weight gain of barn feeding fattening Xinjiang brow calf was higher, and the meat producing capacity was better. There was no significant difference between different barn feeding conditions. [Con clusion]The ways of barn feeding fattening had better daily weight gain in Xinjiang brow calf. This fatte ning way could be demonstrated in Xinjiang area.

  5. SpecialBVC : En hjälp för barn och föräldrar vid uppfödningsproblem?

    OpenAIRE

    2016-01-01

    Bakgrund: Upp till 25 % av alla barn har någon gång under uppväxten någon typ av uppfödningsproblem.  Begreppet uppfödningsproblem brukar innefatta någon form av svårighet med att suga, tugga och svälja och delas ofta in i olika kategorier beroende på symtombild eller tänkt orsak. Symtomen eller den möjliga orsaken får sedan avgöra hur man väljer att behandla problemet. Spektrumet är stort vid uppfödningsproblem, alltifrån svårigheter som inte leder till några egentliga hälsorisker för barnet...

  6. Innovative hybrid biological reactors using membranes; Reactores biologico hibrido innovadores utilizando membranas

    Energy Technology Data Exchange (ETDEWEB)

    Diez, R.; Esteban-Garcia, A. L.; Florio, L. de; Rodriguez-Hernandez, L.; Tejero, I.

    2011-07-01

    In this paper we present two lines of research on hybrid reactors including the use of membranes, although with different functions: RBPM, biofilm reactors and membranes filtration RBSOM, supported biofilm reactors and oxygen membranes. (Author) 14 refs.

  7. Establishment of licensing process for development reactors

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Jong Chull; Yune, Young Gill; Kim, Woong Sik (and others)

    2006-02-15

    A study on licensing processes for development reactors has been performed to prepare the licensing of development reactors developed in Korea. The contents and results of the study are summarized as follows. The licensing processes for nuclear reactors in Korea, U.S.A., Japan, France, U.K., Canada, and IAEA were surveyed and analyzed to obtain technical bases necessary for establishing licensing processes applicable to development reactors in Korea. Based on the technical bases obtained the above analysis, the purpose, power output, and design characteristics of development reactors were analyzed in detail. The analysis results suggested that development reactors should be classified as a new reactor category (called as 'development reactor') separated from the current reactor categories such as the research reactor and the power reactor. Therefore, it is proposed to establish a new reactor category classified as 'development reactor' for the development reactors. And licensing processes, including licensing technical requirements, licensing document requirements, and other regulatory requirements, were also proposed for the development reactors. In order to institutionalize the licensing processes developed in this study, it is necessary to revise the current laws. Therefore, draft provisions of Atomic Energy Act, Enforcement Decree of the Atomic Energy Act, and Enforcement Regulation of the Atomic Energy Act have been developed for the preparation of the future legalization of the licensing processes proposed for the development reactors. Conclusively, a proposal of licensing processes and draft provisions of laws have been developed for the development reactors. The results proposed in this study can be applied directly to the licensing of the future development reactors. Furthermore, they will also contribute to establishing successfully the licensing processes of the development reactors.

  8. Repairing liner of the reactor; Reparacion del liner del reactor

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar H, F. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2001-07-15

    Due to the corrosion problems of the aluminum coating of the reactor pool, a periodic inspections program by ultrasound to evaluate the advance grade and the corrosion speed was settled down. This inspections have shown the necessity to repair some areas, in those that the slimming is significant, of not making it can arrive to the water escape of the reactor pool. The objective of the repair is to place patches of plates of 1/4 inch aluminum thickness in the areas of the reactor 'liner', in those that it has been detected by ultrasound a smaller thickness or similar to 3 mm. To carry out this the fuels are move (of the core and those that are decaying) to a temporary storage, the structure of the core is confined in a tank that this placed inside the pool of the reactor, a shield is placed in the thermal column and it is completely extracted the water for to leave uncover the 'liner' of the reactor. (Author)

  9. Reactor Simulator Testing

    Science.gov (United States)

    Schoenfeld, Michael P.; Webster, Kenny L.; Pearson, Boise Jon

    2013-01-01

    As part of the Nuclear Systems Office Fission Surface Power Technology Demonstration Unit (TDU) project, a reactor simulator test loop (RxSim) was design & built to perform integrated testing of the TDU components. In particular, the objectives of RxSim testing was to verify the operation of the core simulator, the instrumentation and control system, and the ground support gas and vacuum test equipment. In addition, it was decided to include a thermal test of a cold trap purification design and a pump performance test at pump voltages up to 150 V since the targeted mass flow rate of 1.75 kg/s was not obtained in the RxSim at the originally constrained voltage of 120 V. This paper summarizes RxSim testing. The gas and vacuum ground support test equipment performed effectively in NaK fill, loop pressurization, and NaK drain operations. The instrumentation and control system effectively controlled loop temperature and flow rates or pump voltage to targeted settings. The cold trap design was able to obtain the targeted cold temperature of 480 K. An outlet temperature of 636 K was obtained which was lower than the predicted 750 K but 156 K higher than the cold temperature indicating the design provided some heat regeneration. The annular linear induction pump (ALIP) tested was able to produce a maximum flow rate of 1.53 kg/s at 800 K when operated at 150 V and 53 Hz. Keywords: fission, space power, nuclear, liquid metal, NaK.

  10. Reactivity determination in accelerator driven reactors using reactor noise analysis

    Directory of Open Access Journals (Sweden)

    Kostić Ljiljana 1

    2002-01-01

    Full Text Available Feynman-alpha and Rossi-alpha methods are used in traditional nuclear reactors to determine the subcritical reactivity of a system. The methods are based on the measurement of the mean value, variance and the covariance of detector counts for different measurement times. Such methods attracted renewed attention recently with the advent of the so-called accelerator driven reactors (ADS proposed some time ago. The ADS systems, intended to be used either in energy generation or transuranium transmutation, will use a subcritical core with a strong spallation source. A spallation source has statistical properties that are different from those traditionally used by radioactive sources. In such reactors the monitoring of the subcritical reactivity is very important, and a statistical method, such as the Feynman-alpha method, is capable of resolving this problem.

  11. Heterogeneous Transmutation Sodium Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    S. E. Bays

    2007-09-01

    The threshold-fission (fertile) nature of Am-241 is used to destroy this minor actinide by capitalizing upon neutron capture instead of fission within a sodium fast reactor. This neutron-capture and its subsequent decay chain leads to the breeding of even neutron number plutonium isotopes. A slightly moderated target design is proposed for breeding plutonium in an axial blanket located above the active “fast reactor” driver fuel region. A parametric study on the core height and fuel pin diameter-to-pitch ratio is used to explore the reactor and fuel cycle aspects of this design. This study resulted in both non-flattened and flattened core geometries. Both of these designs demonstrated a high capacity for removing americium from the fuel cycle. A reactivity coefficient analysis revealed that this heterogeneous design will have comparable safety aspects to a homogeneous reactor of comparable size. A mass balance analysis revealed that the heterogeneous design may reduce the number of fast reactors needed to close the current once-through light water reactor fuel cycle.

  12. Thermonuclear Reflect AB-Reactor

    CERN Document Server

    Bolonkin, Alexander

    2008-01-01

    The author offers a new kind of thermonuclear reflect reactor. The remarkable feature of this new reactor is a three net AB reflector, which confines the high temperature plasma. The plasma loses part of its energy when it contacts with the net but this loss can be compensated by an additional permanent plasma heating. When the plasma is rarefied (has a small density), the heat flow to the AB reflector is not large and the temperature in the triple reflector net is lower than 2000 - 3000 K. This offered AB-reactor has significantly less power then the currently contemplated power reactors with magnetic or inertial confinement (hundreds-thousands of kW, not millions of kW). But it is enough for many vehicles and ships and particularly valuable for tunnelers, subs and space apparatus, where air to burn chemical fuel is at a premium or simply not available. The author has made a number of innovations in this reactor, researched its theory, developed methods of computation, made a sample computation of typical pr...

  13. Imaging Fukushima Daiichi reactors with muons

    Directory of Open Access Journals (Sweden)

    Haruo Miyadera

    2013-05-01

    Full Text Available A study of imaging the Fukushima Daiichi reactors with cosmic-ray muons to assess the damage to the reactors is presented. Muon scattering imaging has high sensitivity for detecting uranium fuel and debris even through thick concrete walls and a reactor pressure vessel. Technical demonstrations using a reactor mockup, detector radiation test at Fukushima Daiichi, and simulation studies have been carried out. These studies establish feasibility for the reactor imaging. A few months of measurement will reveal the spatial distribution of the reactor fuel. The muon scattering technique would be the best and probably the only way for Fukushima Daiichi to make this determination in the near future.

  14. Fast breeder reactors an engineering introduction

    CERN Document Server

    Judd, A M

    1981-01-01

    Fast Breeder Reactors: An Engineering Introduction is an introductory text to fast breeder reactors and covers topics ranging from reactor physics and design to engineering and safety considerations. Reactor fuels, coolant circuits, steam plants, and control systems are also discussed. This book is comprised of five chapters and opens with a brief summary of the history of fast reactors, with emphasis on international and the prospect of making accessible enormous reserves of energy. The next chapter deals with the physics of fast reactors and considers calculation methods, flux distribution,

  15. Plasma reactor waste management systems

    Science.gov (United States)

    Ness, Robert O., Jr.; Rindt, John R.; Ness, Sumitra R.

    1992-01-01

    The University of North Dakota is developing a plasma reactor system for use in closed-loop processing that includes biological, materials, manufacturing, and waste processing. Direct-current, high-frequency, or microwave discharges will be used to produce plasmas for the treatment of materials. The plasma reactors offer several advantages over other systems, including low operating temperatures, low operating pressures, mechanical simplicity, and relatively safe operation. Human fecal material, sunflowers, oats, soybeans, and plastic were oxidized in a batch plasma reactor. Over 98 percent of the organic material was converted to gaseous products. The solids were then analyzed and a large amount of water and acid-soluble materials were detected. These materials could possibly be used as nutrients for biological systems.

  16. Nuclear Reactor Engineering Analysis Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Carlos Chavez-Mercado; Jaime B. Morales-Sandoval; Benjamin E. Zayas-Perez

    1998-12-31

    The Nuclear Reactor Engineering Analysis Laboratory (NREAL) is a sophisticated computer system with state-of-the-art analytical tools and technology for analysis of light water reactors. Multiple application software tools can be activated to carry out different analyses and studies such as nuclear fuel reload evaluation, safety operation margin measurement, transient and severe accident analysis, nuclear reactor instability, operator training, normal and emergency procedures optimization, and human factors engineering studies. An advanced graphic interface, driven through touch-sensitive screens, provides the means to interact with specialized software and nuclear codes. The interface allows the visualization and control of all observable variables in a nuclear power plant (NPP), as well as a selected set of nonobservable or not directly controllable variables from conventional control panels.

  17. Utilisation of thorium in reactors

    Science.gov (United States)

    Anantharaman, K.; Shivakumar, V.; Saha, D.

    2008-12-01

    India's nuclear programme envisages a large-scale utilisation of thorium, as it has limited deposits of uranium but vast deposits of thorium. The large-scale utilisation of thorium requires the adoption of closed fuel cycle. The stable nature of thoria and the radiological issues associated with thoria poses challenges in the adoption of a closed fuel cycle. A thorium fuel based Advanced Heavy Water Reactor (AHWR) is being planned to provide impetus to development of technologies for the closed thorium fuel cycle. Thoria fuel has been loaded in Indian reactors and test irradiations have been carried out with (Th-Pu) MOX fuel. Irradiated thorium assemblies have been reprocessed and the separated 233U fuel has been used for test reactor KAMINI. The paper highlights the Indian experience with the use of thorium and brings out various issues associated with the thorium cycle.

  18. A tubular focused sonochemistry reactor

    Institute of Scientific and Technical Information of China (English)

    ZHOU GuangPing; LIANG ZhaoFeng; LI ZhengZhong; ZHANG YiHui

    2007-01-01

    This paper presents a new sonochemistry reactor, which consists of a cylindrical tube with a certain length and piezoelectric transducers at tube's end with the longitudinal vibration. The tube can effectively transform the longitudinal vibration into the radial vibration and thereby generates ultrasound. Furthermore, ultrasound can be focused to form high-intensity ultrasonic field inside tube. The reactor boasts of simple structure and its whole vessel wall can radiate ultrasound so that the electroacoustic transfer efficiency is high. The focused ultrasonic field provides good condition for sonochemical reaction. The length of the reactor can be up to 2 meters, and liquids can pass through it continuously, so it can be widely applied in liquid processing such as sonochemistry.

  19. A compact Tokamak transmutation reactor

    Institute of Scientific and Technical Information of China (English)

    QiuLi-Jian; XiaoBing-Jia

    1997-01-01

    The low aspect ration tokamak is proposed for the driver of a transmutation reactor.The main parameters of the reactor core,neutronic analysis of the blanket are given>the neutron wall loading can be lowered from the magnitude order of 1 MW/m2 to 0.5MW/m2 which is much easier to reach in the near future,and the transmutation efficiency (fission/absorption ratio)is raised further.The blanket power density is about 200MW/m3 which is not difficult to deal with.The key components such as diverter and center conductor post are also designed and compared with conventional TOkamak,Finally,by comparison with the other drivers such as FBR,PWR and accelerator,it can be anticipated that the low aspect ratio transmutation reactor would be one way of fusion energy applications in the near future.

  20. Investigation of KW reactor incident

    Energy Technology Data Exchange (ETDEWEB)

    Sturges, D G [USAEC Hanford Operations Office, Richland, WA (United States); Hauff, T W; Greager, O H [General Electric Co., Richland, WA (United States). Hanford Atomic Products Operation

    1955-02-11

    The new KW reactor was placed in operation on January 4, 1955, and had been running at relatively low power levels for only 17 hours when it was shut down because of a process tube water leak which appeared to be associated with a slug rupture. After several days of unrewarding effort to remove the slugs and tube by customary methods, it developed that considerable melting of the tube and slugs had taken place. It was then evident that removal of the stuck mass and repairs to the damaged tube channel would require unusual measures that were certain to extend the reactor outage for several weeks. This report documents the work and findings of the Committee which investigated the KW reactor incident. Its content represents unanimous agreement among the three Committee members.

  1. Fundamentals of Nuclear Reactor Physics

    CERN Document Server

    Lewis, E E

    2008-01-01

    This new streamlined text offers a one-semester treatment of the essentials of how the fission nuclear reactor works, the various approaches to the design of reactors, and their safe and efficient operation. The book includes numerous worked-out examples and end-of-chapter questions to help reinforce the knowledge presented. This textbook offers an engineering-oriented introduction to nuclear physics, with a particular focus on how those physics are put to work in the service of generating nuclear-based power, particularly the importance of neutron reactions and neutron behavior. Engin

  2. PITR: Princeton Ignition Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    1978-12-01

    The principal objectives of the PITR - Princeton Ignition Test Reactor - are to demonstrate the attainment of thermonuclear ignition in deuterium-tritium, and to develop optimal start-up techniques for plasma heating and current induction, in order to determine the most favorable means of reducing the size and cost of tokamak power reactors. This report describes the status of the plasma and engineering design features of the PITR. The PITR geometry is chosen to provide the highest MHD-stable values of beta in a D-shaped plasma, as well as ease of access for remote handling and neutral-beam injection.

  3. Analysis of Adiabatic Batch Reactor

    Directory of Open Access Journals (Sweden)

    Erald Gjonaj

    2016-05-01

    Full Text Available A mixture of acetic anhydride is reacted with excess water in an adiabatic batch reactor to form an exothermic reaction. The concentration of acetic anhydride and the temperature inside the adiabatic batch reactor are calculated with an initial temperature of 20°C, an initial temperature of 30°C, and with a cooling jacket maintaining the temperature at a constant of 20°C. The graphs of the three different scenarios show that the highest temperatures will cause the reaction to occur faster.

  4. External fuel thermionic reactor system.

    Science.gov (United States)

    Mondt, J. F.; Peelgren, M. L.

    1971-01-01

    Thermionic reactors are prime candidates for nuclear electric propulsion. The national thermionic reactor effort is concentrated on the flashlight concept with the external-fuel concept as the backup. The external-fuel concept is very adaptable to a completely modular power subsystem which is attractive for highly reliable long-life applications. The 20- to 25-cm long, externally-fueled converters have been designed, fabricated, and successfully tested with many thermal cycles by electrical heating. However, difficulties have been encountered during encapsulation for nuclear heated tests and none have been started to date. These nuclear tests are required to demonstrate the concept feasibility.

  5. Reactor shutdown delays medical procedures

    Science.gov (United States)

    Gwynne, Peter

    2008-01-01

    A longer-than-expected maintenance shutdown of the Canadian nuclear reactor that produces North America's entire supply of molybdenum-99 - from which the radioactive isotopes technetium-99 and iodine-131 are made - caused delays to the diagnosis and treatment of thousands of seriously ill patients last month. Technetium-99 is a key component of nuclear-medicine scans, while iodine-131 is used to treat cancer and other diseases of the thyroid. Production eventually resumed, but only after the Canadian government had overruled the Canadian Nuclear Safety Commission (CNSC), which was still concerned about the reactor's safety.

  6. Request for Naval Reactors Comment on Proposed Prometheus Space Flight Nuclear Reactor High Tier Reactor Safety Requirements and for Naval Reactors Approval to Transmit These Requirements to JPL

    Energy Technology Data Exchange (ETDEWEB)

    D. Kokkinos

    2005-04-28

    The purpose of this letter is to request Naval Reactors comments on the nuclear reactor high tier requirements for the PROMETHEUS space flight reactor design, pre-launch operations, launch, ascent, operation, and disposal, and to request Naval Reactors approval to transmit these requirements to Jet Propulsion Laboratory to ensure consistency between the reactor safety requirements and the spacecraft safety requirements. The proposed PROMETHEUS nuclear reactor high tier safety requirements are consistent with the long standing safety culture of the Naval Reactors Program and its commitment to protecting the health and safety of the public and the environment. In addition, the philosophy on which these requirements are based is consistent with the Nuclear Safety Policy Working Group recommendations on space nuclear propulsion safety (Reference 1), DOE Nuclear Safety Criteria and Specifications for Space Nuclear Reactors (Reference 2), the Nuclear Space Power Safety and Facility Guidelines Study of the Applied Physics Laboratory.

  7. Oregon State University TRIGA Reactor annual report

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, T.V.; Johnson, A.G.; Bennett, S.L.; Ringle, J.C.

    1979-08-31

    The use of the Oregon State University TRIGA Reactor during the year ending June 30, 1979, is summarized. Environmental and radiation protection data related to reactor operation and effluents are included.

  8. Reactor Antineutrino Signals at Morton and Boulby

    CERN Document Server

    Dye, Steve

    2016-01-01

    Increasing the distance from which an antineutrino detector is capable of monitoring the operation of a registered reactor, or discovering a clandestine reactor, strengthens the Non-Proliferation of Nuclear Weapons Treaty. This report presents calculations of reactor antineutrino interactions, from quasi-elastic neutrino-proton scattering and elastic neutrino-electron scattering, in a water-based detector operated >10 km from a commercial power reactor. It separately calculates signal from the proximal reactor and background from all other registered reactors. The main results are interaction rates and kinetic energy distributions of charged leptons scattered from quasi-elastic and elastic processes. Comparing signal and background distributions evaluates reactor monitoring capability. Scaling the results to detectors of different sizes, target media, and standoff distances is straightforward. Calculations are for two examples of a commercial reactor (P_th~3 GW) operating nearby (L~20 km) an underground facil...

  9. Transmutation of actinides in power reactors.

    Science.gov (United States)

    Bergelson, B R; Gerasimov, A S; Tikhomirov, G V

    2005-01-01

    Power reactors can be used for partial short-term transmutation of radwaste. This transmutation is beneficial in terms of subsequent storage conditions for spent fuel in long-term storage facilities. CANDU-type reactors can transmute the main minor actinides from two or three reactors of the VVER-1000 type. A VVER-1000-type reactor can operate in a self-service mode with transmutation of its own actinides.

  10. Laminar Entrained Flow Reactor (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2014-02-01

    The Laminar Entrained Flow Reactor (LEFR) is a modular, lab scale, single-user reactor for the study of catalytic fast pyrolysis (CFP). This system can be employed to study a variety of reactor conditions for both in situ and ex situ CFP.

  11. Some new viewpoints in reactor noise analysis

    Institute of Scientific and Technical Information of China (English)

    罗征培; 李富; 等

    1996-01-01

    It is propsed that the linearity criterion and order criterion via frequency spectrum features without any limitation of the model's phase can be used in reactor noise analysis.The time constant,natural frequency as well as the recovered transfer function of reactors can bhe obtained via the analyzable model based on reactor noise.

  12. Heat-pipe thermionic reactor concept

    DEFF Research Database (Denmark)

    Storm Pedersen, E.

    1967-01-01

    Main components are reactor core, heat pipe, thermionic converter, secondary cooling system, and waste heat radiator; thermal power generated in reactor core is transported by heat pipes to thermionic converters located outside reactor core behind radiation shield; thermionic emitters are in direct...

  13. Heavy Water Reactor; Reacteurs a eau lourde

    Energy Technology Data Exchange (ETDEWEB)

    Yu, St.; HOpwood, J.; Meneley, D. [Energie Atomique du Canada (Canada)

    2000-04-01

    This document deals with the Heavy Water Reactor (HWR) technology and especially the Candu (Canada Deuterium Uranium) reactor. This reactors type offers many advantages that promote them for the future. General concepts, a description of the Candu nuclear power plants, the safety systems, the fuel cycle and economical and environmental aspects are included. (A.L.B.)

  14. Operating Modes Of Chemical Reactors Of Polymerization

    Directory of Open Access Journals (Sweden)

    Meruyert Berdieva

    2012-05-01

    Full Text Available In the work the issues of stable technological modes of operation of main devices of producing polysterol reactors have been researched as well as modes of stable operation of a chemical reactor have been presented, which enables to create optimum mode parameters of polymerization process, to prevent emergency situations of chemical reactor operation in industrial conditions.

  15. Nuclear Reactors and Technology; (USA)

    Energy Technology Data Exchange (ETDEWEB)

    Cason, D.L.; Hicks, S.C. (eds.)

    1991-01-01

    Nuclear Reactors and Technology (NRT) announces on a monthly basis the current worldwide information available from the open literature on nuclear reactors and technology, including all aspects of power reactors, components and accessories, fuel elements, control systems, and materials. This publication contains the abstracts of DOE reports, journal articles, conference papers, patents, theses, and monographs added to the Energy Science and Technology Database (EDB) during the past month. Also included are US information obtained through acquisition programs or interagency agreements and international information obtained through the International Energy Agency's Energy Technology Data Exchange or government-to-government agreements. The digests in NRT and other citations to information on nuclear reactors back to 1948 are available for online searching and retrieval on EDB and Nuclear Science Abstracts (NSA) database. Current information, added daily to EDB, is available to DOE and its contractors through the DOE integrated Technical Information System. Customized profiles can be developed to provide current information to meet each user's needs.

  16. A Simple Tubular Reactor Experiment.

    Science.gov (United States)

    Hudgins, Robert R.; Cayrol, Bertrand

    1981-01-01

    Using the hydrolysis of crystal violet dye by sodium hydroxide as an example, the theory, apparatus, and procedure for a laboratory demonstration of tubular reactor behavior are described. The reaction presented can occur at room temperature and features a color change to reinforce measured results. (WB)

  17. Silica-Immobilized Enzyme Reactors

    Science.gov (United States)

    2007-08-01

    immobilized artificial membrane chromatography and lysophospholipid micellar electrokinetic chromatography . J. Chromatogr. A 1998, 810, 95-103. 50...Journal of Liquid Chromatography and Related Technologies. Air Force Research Laboratory Materials and Manufacturing Directorate Airbase...immobilized enzyme reactors (IMERs) can also be integrated directly to further analytical methods such as liquid chromatography or mass spectrometry.[6] In

  18. British high flux beam reactor.

    Science.gov (United States)

    Egelstaff, P A

    1970-10-24

    The neutron scattering technique has become an accepted method for the study of condensed matter. Because of the great scientific and technical value of neutron experiments and the growing body of users, several proposals have been made during the past decade for a nuclear reactor devoted primarily to this technique. This article reviews the reasons for and history behind these proposals.

  19. Nuclear reactors and fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2014-07-01

    The Nuclear Fuel Center (CCN) of IPEN produces nuclear fuel for the continuous operation of the IEA-R1 research reactor of IPEN. The serial production started in 1988, when the first nuclear fuel element was delivered for IEA-R1. In 2011, CCN proudly presents the 100{sup th} nuclear fuel element produced. Besides routine production, development of new technologies is also a permanent concern at CCN. In 2005, U{sub 3}O{sub 8} were replaced by U{sub 3}Si{sub 2}-based fuels, and the research of U Mo is currently under investigation. Additionally, the Brazilian Multipurpose Research Reactor (RMB), whose project will rely on the CCN for supplying fuel and uranium targets. Evolving from an annual production from 10 to 70 nuclear fuel elements, plus a thousand uranium targets, is a huge and challenging task. To accomplish it, a new and modern Nuclear Fuel Factory is being concluded, and it will provide not only structure for scaling up, but also a safer and greener production. The Nuclear Engineering Center has shown, along several years, expertise in the field of nuclear, energy systems and correlated areas. Due to the experience obtained during decades in research and technological development at Brazilian Nuclear Program, personnel has been trained and started to actively participate in design of the main system that will compose the Brazilian Multipurpose Reactor (RMB) which will make Brazil self-sufficient in production of radiopharmaceuticals. The institution has participated in the monitoring and technical support concerning the safety, licensing and modernization of the research reactors IPEN/MB-01 and IEA-R1. Along the last two decades, numerous specialized services of engineering for the Brazilian nuclear power plants Angra 1 and Angra 2 have been carried out. The contribution in service, research, training, and teaching in addition to the development of many related technologies applied to nuclear engineering and correlated areas enable the institution to

  20. 烤房类型对烤后烟叶质量的影响%Effect of Differont Types of Curing Barns on Tobacoo Leaf Quantity after Curing

    Institute of Scientific and Technical Information of China (English)

    黄维

    2012-01-01

    [目的]考察3种类型烤房在烟叶鲜叶初加工过程中的整体效果.[方法]采用云南烟区普遍使用的气流下降式密集烤房密集型烤房、气流上升式密集烤房和普通立式炉小烤房3种烤房,分析比较不同类型烤房烤后烟叶的主要化学成分、物理特性、外观等级、评吸质量的差异.[结果]不同类型烤房烤后烟叶中上等烟叶比例气流下降式密集烤房比普通立式炉小烤房密集烤房分别高出2.86%和0.87%,比气流上升式密集烤房高出7.75%和4.29%;不同类型烤房烤后烟叶根据多数化学指标均为气流下降式密集烤房烤房烤后烟叶化学成分最为协调,气流上升式密集烤房次之,普通立式炉小烤房较差;不同类型烤房烤后上中下部位烟叶感官质量和物理特性均为气流下降式密集烤房最好,气流上升式密集烤房次之,普通立式炉小烤房效果较差.[结论]气流下降式密集电烤房结构设计合理可以推广应用.%[ Objective] To investigate the effect of three types of curing bams on the primary processing quality of fresh tobacco leaves. [ Method] Airflow-descending dense curing barna,airflow-ascending dense curing bams and common vertical furnace-curing bams in Yunnan tobacco area were adopted for analyzing and comparing the difference of main chemical components,physical characteristics,appearance grade and smoking quality of tobaccos cured by the three types of curing bamB. [ Result ] The medium and high-grade tobacco proportions after being cured by the airflow-descending dense curing barns were higher than that by the common vertical furnace min-curing bams and dense curing bams by 2.86% and 0.87% respectively,and higher than that by airflow-ascending dense curing bams hy 7.75% and 4.29%. According to a majority of chemical indicators,the tobacco chemical components cured by airflow-descending dense curing bams were the most coordinate,followed by the airflow

  1. Radiochemical determination of the neutron capture cross sections of {sup 241}Am irradiated in the JMTR reactor

    Energy Technology Data Exchange (ETDEWEB)

    Shinohara, N.; Hatsukawa, Y.; Hata, K.; Kohno, N. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    The thermal neutron capture cross section {sigma}{sub 0} and Resonance integral I{sub 0} of {sup 241}Am leading to the production of {sup 242m}Am and {sup 242g}Am were measured by radiochemical method. The cross sections obtained in this study are {sigma}{sub 0}=60.9 {+-} 2.6 barn, I{sub 0}=213 {+-} 13 barn for {sup 241}Am(n,{gamma}){sup 242m}Am and {sigma}{sub 0}=736 {+-} 31 barn, I{sub 0}=1684 {+-} 92 barn for {sup 241}Am(n,{gamma}){sup 242g}Am. (author)

  2. Heterogeneous Recycling in Fast Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Forget, Benoit; Pope, Michael; Piet, Steven J.; Driscoll, Michael

    2012-07-30

    Current sodium fast reactor (SFR) designs have avoided the use of depleted uranium blankets over concerns of creating weapons grade plutonium. While reducing proliferation risks, this restrains the reactor design space considerably. This project will analyze various blanket and transmutation target configurations that could broaden the design space while still addressing the non-proliferation issues. The blanket designs will be assessed based on the transmutation efficiency of key minor actinide (MA) isotopes and also on mitigation of associated proliferation risks. This study will also evaluate SFR core performance under different scenarios in which depleted uranium blankets are modified to include minor actinides with or without moderators (e.g. BeO, MgO, B4C, and hydrides). This will be done in an effort to increase the sustainability of the reactor and increase its power density while still offering a proliferation resistant design with the capability of burning MA waste produced from light water reactors (LWRs). Researchers will also analyze the use of recycled (as opposed to depleted) uranium in the blankets. The various designs will compare MA transmutation efficiency, plutonium breeding characteristics, proliferation risk, shutdown margins and reactivity coefficients with a current reference sodium fast reactor design employing homogeneous recycling. The team will also evaluate the out-of-core accumulation and/or burn-down rates of MAs and plutonium isotopes on a cycle-by-cycle basis. This cycle-by-cycle information will be produced in a format readily usable by the fuel cycle systems analysis code, VISION, for assessment of the sustainability of the deployment scenarios.

  3. A new MTR fuel for a new MTR reactor: UMo for the Jules Horowitz reactor

    Energy Technology Data Exchange (ETDEWEB)

    Guigon, B. [CEA Cadarache, F-13108 Saint Paul lez Durance (France); Vacelet, H. [CERCA, Romans (France); Dornbusch, D. [Technicatome, Aix en Provence (France)

    2000-07-01

    Within some years, the Jules Horowitz Reactor will be the only working experimental reactor (material and fuel testing reactor) in France. It will have to provide facilities for a wide range of needs from activation analysis to power reactor fuel qualification. In this paper the main characteristics of the Jules Horowitz Reactor are presented. Safety criteria are explained. Finally, merits and disadvantages of UMo compared to the standard U{sub 3}Si{sub 2} fuel are discussed. (author)

  4. Den komplexa väven Att organisera för barns övergångar till och från förskoleklass

    Directory of Open Access Journals (Sweden)

    Helena Ackesjö

    2015-09-01

    Full Text Available This study focuses on how children's transitions to and from preschool classes are organized in different schools. Principal’s arguments for this organization were sought via a web-based survey and analyzed using the frame factor theory in addition to theories of practical sense and the concept of continuity. The results show that children tend to make more transitions between social communities the younger they are. The distribution of the principal’s answers show that the majority of them, because of external conditions, split the preschool groups to new classes in the transition to preschool class. However, the same movements are not indicated in the transition to first grade. The results show how the work of organizing chidren’s transitions represent a complex web of external actual conditions as the number of children and the recruitment area of the school, the internal logics and ideas about what is best for children and best for continued learning as well as the school's own traditions of working with transitions. Föreliggande studie fokuserar på hur barns övergångar till och från förskoleklass organiseras på olika skolor. Via en webbaserad enkät söks skolledares argument för denna organisering. I analysen nyttjas ett ramfaktorteoretiskt tänkande som kompletteras med teorier om praktiskt förnuft samt kontinuitetsbegreppet. Resultaten visar att barn tenderar att göra fler övergångar mellan barngrupper och sociala gemenskaper ju yngre de är. Fördelningen av skolledarnas svar visar att majoriteten, på grund av yttre villkor, delar förskolegrupperna till nya klasser i övergången till förskoleklass. Däremot indikeras inte samma rörlighet i övergången till årskurs 1. Resultaten visar hur arbetet med att organisera övergångarna utgör en komplex väv av yttre faktiska villkor som barnantal och upptagningsområdets storlek, av inre logiker och föreställningar om vad som är det bästa för barnen och det b

  5. Improvements of sound localization abilities by the facial ruff of the barn owl (Tyto alba as demonstrated by virtual ruff removal.

    Directory of Open Access Journals (Sweden)

    Laura Hausmann

    Full Text Available BACKGROUND: When sound arrives at the eardrum it has already been filtered by the body, head, and outer ear. This process is mathematically described by the head-related transfer functions (HRTFs, which are characteristic for the spatial position of a sound source and for the individual ear. HRTFs in the barn owl (Tyto alba are also shaped by the facial ruff, a specialization that alters interaural time differences (ITD, interaural intensity differences (ILD, and the frequency spectrum of the incoming sound to improve sound localization. Here we created novel stimuli to simulate the removal of the barn owl's ruff in a virtual acoustic environment, thus creating a situation similar to passive listening in other animals, and used these stimuli in behavioral tests. METHODOLOGY/PRINCIPAL FINDINGS: HRTFs were recorded from an owl before and after removal of the ruff feathers. Normal and ruff-removed conditions were created by filtering broadband noise with the HRTFs. Under normal virtual conditions, no differences in azimuthal head-turning behavior between individualized and non-individualized HRTFs were observed. The owls were able to respond differently to stimuli from the back than to stimuli from the front having the same ITD. By contrast, such a discrimination was not possible after the virtual removal of the ruff. Elevational head-turn angles were (slightly smaller with non-individualized than with individualized HRTFs. The removal of the ruff resulted in a large decrease in elevational head-turning amplitudes. CONCLUSIONS/SIGNIFICANCE: The facial ruff a improves azimuthal sound localization by increasing the ITD range and b improves elevational sound localization in the frontal field by introducing a shift of iso-ILD lines out of the midsagittal plane, which causes ILDs to increase with increasing stimulus elevation. The changes at the behavioral level could be related to the changes in the binaural physical parameters that occurred after the

  6. Applying Effect of Insulating Material Made of Mineral Binder and Expanded Polystyrene Granule in Bulk Curing Barn%胶粉聚苯颗粒保温材料在密集烤房中应用效果研究

    Institute of Scientific and Technical Information of China (English)

    张丽英; 杨启冰; 谢帮金; 刘勇; 李立新; 齐飞

    2013-01-01

    In order to know applying effect of insulating material made of mineral binder and expanded polystyrene granule in bulk curing barn,the curing effects of bulk curing barn covered with or without insulating material made of mineral binder and expanded polystyrene granule were compared.The results showed that insulating material made of mineral binder and expanded polystyrene granule can reduce the heat loss for bulk curing barn,and coal saving rate and power saving rate reached 26% and 21.89%,respectively.Therefore,it effectively reduce the curing cost,moreover,it also improved the curing quality of top layer leaves through lowering green degree.%为了了解胶粉聚苯颗粒保温材料在密集烤房中的使用效果,试验对比了涂抹、不涂抹胶粉聚苯颗粒保温材料密集烤房中烟叶的烘烤效果.结果表明:胶粉聚苯颗粒保温材料可以减少密集烤房的热量损失,节煤26%,节电21.89%,有效地降低了烘烤成本,且能降低顶层烟叶烘烤后的含青度,提高顶层烟叶烘烤质量.

  7. Test of the Three Layers Bulk Curing Barn into Four Layers%密集烤房“3层改4层”烘烤试验研究

    Institute of Scientific and Technical Information of China (English)

    赵晓丹; 邱路平; 王东明; 肖先仪; 王文君

    2013-01-01

    通过对比试验研究了密集烤房3层和4层烘烤方式对烤烟能耗和烟叶品质的影响。结果表明:与常规3层挂烟相比,4层挂烟方式明显增加了烤房容量,每1kg干烟用工成本下降20.06%,耗能成本降低22.78%,烤后烟叶质量优于3层烘烤,具有广泛的推广价值。%In order to investigate the effect of three layers bulk curing and four layers on energy consumption and tobacco quality during the tobacco curing,the experiment of loading tobacco leaf was conducted with tradi-tional loading and mezzo loading.The results showed that that compared with the three layers bulk curing barn, the amount of loading tobacco in four layers bulk curing barn were increasing,the cost of labor force and the en-ergy consumption reduced by 20.06% and 22.78% per kilogram respectively,the quality of the four layers bulk curing barn was superior than that of the traditional method and there is extended significance to popularize.

  8. Neutrino Mixing Discriminates Geo-reactor Models

    CERN Document Server

    Dye, S T

    2009-01-01

    Geo-reactor models suggest the existence of natural nuclear reactors at different deep-earth locations with loosely defined output power. Reactor fission products undergo beta decay with the emission of electron antineutrinos, which routinely escape the earth. Neutrino mixing distorts the energy spectrum of the electron antineutrinos. Characteristics of the distorted spectrum observed at the earth's surface could specify the location of a geo-reactor, discriminating the models and facilitating more precise power measurement. The existence of a geo-reactor with known position could enable a precision measurement of the neutrino oscillation parameter delta-mass-squared.

  9. Reactor monitoring and safeguards using antineutrino detectors

    CERN Document Server

    Bowden, N S

    2008-01-01

    Nuclear reactors have served as the antineutrino source for many fundamental physics experiments. The techniques developed by these experiments make it possible to use these very weakly interacting particles for a practical purpose. The large flux of antineutrinos that leaves a reactor carries information about two quantities of interest for safeguards: the reactor power and fissile inventory. Measurements made with antineutrino detectors could therefore offer an alternative means for verifying the power history and fissile inventory of a reactors, as part of International Atomic Energy Agency (IAEA) and other reactor safeguards regimes. Several efforts to develop this monitoring technique are underway across the globe.

  10. Reactor assessments of advanced bumpy torus configurations

    Energy Technology Data Exchange (ETDEWEB)

    Uckan, N.A.; Owen, L.W.; Spong, D.A.; Miller, R.L.; Ard, W.B.; Pipkins, J.F.; Schmitt, R.J.

    1983-01-01

    Recently, several configurational approaches and concept improvement schemes were introduced for enhancing the performance of the basic ELMO Bumpy Torus (EBT) concept and for improving its reactor potential. These configurations include planar racetrack and square geometries, Andreoletti coil systems, and bumpy torus-stellarator hybrids (which include twisted racetrack and helical axis stellarator-snakey torus). Preliminary evaluations of reactor implications of each of these configurations have been carried out based on magnetics (vacuum) calculations, transport and scaling relationships, and stability properties. Results indicate favorable reactor projections with a significant reduction in reactor physical size as compared to conventional EBT reactor designs carried out in the past.

  11. Detection of antineutrinos for reactor monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yeong Duk [Center for Underground Physics, Institute of Basic Science, Daejeon (Korea, Republic of)

    2016-04-15

    Reactor neutrinos have been detected in the past 50 years by various detectors for different purposes. Beginning in the 1980s, neutrino physicists have tried to use neutrinos to monitor reactors and develop an optimized detector for nuclear safeguards. Recently, motivated by neutrino oscillation physics, the technology and scale of reactor neutrino detection have progressed considerably. In this review, I will give an overview of the detection technology for reactor neutrinos, and describe the issues related to further improvements in optimized detectors for reactor monitoring.

  12. CFD Simulation on Ethylene Furnace Reactor Tubes

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Different mathematical models for ethylene furnace reactor tubes were reviewed. On the basis of these models a new mathematical simulation approach for reactor tubes based on computational fluid dynamics (CFD) technique was presented. This approach took the flow, heat transfer, mass transfer and thermal cracking reactions in the reactor tubes into consideration. The coupled reactor model was solved with the SIMPLE algorithm. Some detailed information about the flow field, temperature field and concentration distribution in the reactor tubes was obtained, revealing the basic characteristics of the hydrodynamic phenomena and reaction behavior in the reactor tubes. The CFD approach provides the necessary information for conclusive decisions regarding the production optimization, the design and improvement of reactor tubes, and the new techniques implementation.

  13. Advanced reactor physics methods for heterogeneous reactor cores

    Science.gov (United States)

    Thompson, Steven A.

    To maintain the economic viability of nuclear power the industry has begun to emphasize maximizing the efficiency and output of existing nuclear power plants by using longer fuel cycles, stretch power uprates, shorter outage lengths, mixed-oxide (MOX) fuel and more aggressive operating strategies. In order to accommodate these changes, while still satisfying the peaking factor and power envelope requirements necessary to maintain safe operation, more complexity in commercial core designs have been implemented, such as an increase in the number of sub-batches and an increase in the use of both discrete and integral burnable poisons. A consequence of the increased complexity of core designs, as well as the use of MOX fuel, is an increase in the neutronic heterogeneity of the core. Such heterogeneous cores introduce challenges for the current methods that are used for reactor analysis. New methods must be developed to address these deficiencies while still maintaining the computational efficiency of existing reactor analysis methods. In this thesis, advanced core design methodologies are developed to be able to adequately analyze the highly heterogeneous core designs which are currently in use in commercial power reactors. These methodological improvements are being pursued with the goal of not sacrificing the computational efficiency which core designers require. More specifically, the PSU nodal code NEM is being updated to include an SP3 solution option, an advanced transverse leakage option, and a semi-analytical NEM solution option.

  14. Reactor pulse repeatability studies at the annular core research reactor

    Energy Technology Data Exchange (ETDEWEB)

    DePriest, K.R. [Applied Nuclear Technologies, Sandia National Laboratories, Mail Stop 1146, Post Office Box 5800, Albuquerque, NM 87185-1146 (United States); Trinh, T.Q. [Nuclear Facility Operations, Sandia National Laboratories, Mail Stop 0614, Post Office Box 5800, Albuquerque, NM 87185-1146 (United States); Luker, S. M. [Applied Nuclear Technologies, Sandia National Laboratories, Mail Stop 1146, Post Office Box 5800, Albuquerque, NM 87185-1146 (United States)

    2011-07-01

    The Annular Core Research Reactor (ACRR) at Sandia National Laboratories is a water-moderated pool-type reactor designed for testing many types of objects in the pulse and steady-state mode of operations. Personnel at Sandia began working to improve the repeatability of pulse operations for experimenters in the facility. The ACRR has a unique UO{sub 2}-BeO fuel that makes the task of producing repeatable pulses difficult with the current operating procedure. The ACRR produces a significant quantity of photoneutrons through the {sup 9}Be({gamma}, n){sup 8}Be reaction in the fuel elements. The photoneutrons are the result of the gammas produced during fission and in fission product decay, so their production is very much dependent on the reactor power history and changes throughout the day/week of experiments in the facility. Because the photoneutrons interfere with the delayed-critical measurements required for accurate pulse reactivity prediction, a new operating procedure was created. The photoneutron effects at delayed critical are minimized when using the modified procedure. In addition, the pulse element removal time is standardized for all pulse operations with the modified procedure, and this produces less variation in reactivity removal times. (authors)

  15. In-reactor performance of pressure tubes in CANDU reactors

    Science.gov (United States)

    Rodgers, D. K.; Coleman, C. E.; Griffiths, M.; Bickel, G. A.; Theaker, J. R.; Muir, I.; Bahurmuz, A. A.; Lawrence, S. St.; Resta Levi, M.

    2008-12-01

    The pressure tubes in CANDU reactors have been operating for times up to about 25 years. The in-reactor performance of Zr-2.5Nb pressure tubes has been evaluated by sampling and periodic inspection. This paper describes the behaviour and discusses the factors controlling the behaviour of these components in currently operating CANDU reactors. The mechanical properties (such as ultimate tensile strength, UTS, and fracture toughness), and delayed-hydride-cracking properties (crack growth rate Vc, and threshold stress intensity factor, KIH) change with irradiation; the former reach a limiting value at a fluence of Pressure tubes exhibit elongation and diametral expansion. The deformation behaviour is a function of operating conditions and material properties that vary from tube-to-tube and as a function of axial location. Semi-empirical predictive models have been developed to describe the deformation response of average tubes as a function of operating conditions. For corrosion and, more importantly deuterium pickup, semi-empirical predictive models have also been developed to represent the behaviour of an average tube. The effect of material variability on corrosion behaviour is less well defined compared with other properties. Improvements in manufacturing have increased fracture resistance by minimising trace elements, especially H and Cl, and reduced variability by tightening controls on forming parameters, especially hot-working temperatures.

  16. On estimation and identifiability issues of sex-linked inheritance with a case study of pigmentation in Swiss barn owl (Tyto alba).

    Science.gov (United States)

    Larsen, Camilla T; Holand, Anna M; Jensen, Henrik; Steinsland, Ingelin; Roulin, Alexandre

    2014-05-01

    Genetic evaluation using animal models or pedigree-based models generally assume only autosomal inheritance. Bayesian animal models provide a flexible framework for genetic evaluation, and we show how the model readily can accommodate situations where the trait of interest is influenced by both autosomal and sex-linked inheritance. This allows for simultaneous calculation of autosomal and sex-chromosomal additive genetic effects. Inferences were performed using integrated nested Laplace approximations (INLA), a nonsampling-based Bayesian inference methodology. We provide a detailed description of how to calculate the inverse of the X- or Z-chromosomal additive genetic relationship matrix, needed for inference. The case study of eumelanic spot diameter in a Swiss barn owl (Tyto alba) population shows that this trait is substantially influenced by variation in genes on the Z-chromosome ([Formula: see text] and [Formula: see text]). Further, a simulation study for this study system shows that the animal model accounting for both autosomal and sex-chromosome-linked inheritance is identifiable, that is, the two effects can be distinguished, and provides accurate inference on the variance components.

  17. Infection Dynamics and Antimicrobial Resistance Profile of Salmonella Paratyphi B d-tartrate Positive (Java) in a Persistently Infected Broiler Barn

    Science.gov (United States)

    Kloska, Franziska; Beyerbach, Martin; Klein, Günter

    2017-01-01

    The infection dynamics of S. Java were examined in three consecutive rearing periods on a broiler farm in Northwestern Germany which had been persistently infected with S. Java for more than five years. The barn was investigated for Salmonella occurrence after cleaning and disinfection to verify the persistent contamination of the broiler house with S. Java before the start of the first rearing cycle. Confirmation of Salmonella absence in day-old chicks (time-point 1) as well as early establishment of infection between days 5–7 (time-point 2) were confirmed by caecal swabs prepared for qPCR and classical microbiological methods. At three time-periods (between days 11–15 (time-point 3), days 25–28 (time-point 4), and days 38–40 (time-point 5)) caecal content was examined for colony forming units (CFU) Salmonella/g. In general, there was an increase in Salmonella Java load at time-point 4 compared to time-points 3 and 5. Therefore, we observed a bell-shaped course of infection resulting in higher rates of Salmonella CFU/g prior to prethinning than at final slaughter. The antimicrobial susceptibility testing revealed resistance to tetracycline, fluorquinolones, trimethoprim, and cefoxitin. PMID:28117713

  18. Agricultural land use and human presence around breeding sites increase stress-hormone levels and decrease body mass in barn owl nestlings.

    Science.gov (United States)

    Almasi, Bettina; Béziers, Paul; Roulin, Alexandre; Jenni, Lukas

    2015-09-01

    Human activities can have a suite of positive and negative effects on animals and thus can affect various life history parameters. Human presence and agricultural practice can be perceived as stressors to which animals react with the secretion of glucocorticoids. The acute short-term secretion of glucocorticoids is considered beneficial and helps an animal to redirect energy and behaviour to cope with a critical situation. However, a long-term increase of glucocorticoids can impair e.g. growth and immune functions. We investigated how nestling barn owls (Tyto alba) are affected by the surrounding landscape and by human activities around their nest sites. We studied these effects on two response levels: (a) the physiological level of the hypothalamus-pituitary-adrenal axis, represented by baseline concentrations of corticosterone and the concentration attained by a standardized stressor; (b) fitness parameters: growth of the nestlings and breeding performance. Nestlings growing up in intensively cultivated areas showed increased baseline corticosterone levels late in the season and had an increased corticosterone release after a stressful event, while their body mass was decreased. Nestlings experiencing frequent anthropogenic disturbance had elevated baseline corticosterone levels, an increased corticosterone stress response and a lower body mass. Finally, breeding performance was better in structurally more diverse landscapes. In conclusion, anthropogenic disturbance affects offspring quality rather than quantity, whereas agricultural practices affect both life history traits.

  19. Fluidized bed coal combustion reactor

    Science.gov (United States)

    Moynihan, P. I.; Young, D. L. (Inventor)

    1981-01-01

    A fluidized bed coal reactor includes a combination nozzle-injector ash-removal unit formed by a grid of closely spaced open channels, each containing a worm screw conveyor, which function as continuous ash removal troughs. A pressurized air-coal mixture is introduced below the unit and is injected through the elongated nozzles formed by the spaces between the channels. The ash build-up in the troughs protects the worm screw conveyors as does the cooling action of the injected mixture. The ash layer and the pressure from the injectors support a fluidized flame combustion zone above the grid which heats water in boiler tubes disposed within and/or above the combustion zone and/or within the walls of the reactor.

  20. Nuclear reactor alignment plate configuration

    Energy Technology Data Exchange (ETDEWEB)

    Altman, David A; Forsyth, David R; Smith, Richard E; Singleton, Norman R

    2014-01-28

    An alignment plate that is attached to a core barrel of a pressurized water reactor and fits within slots within a top plate of a lower core shroud and upper core plate to maintain lateral alignment of the reactor internals. The alignment plate is connected to the core barrel through two vertically-spaced dowel pins that extend from the outside surface of the core barrel through a reinforcement pad and into corresponding holes in the alignment plate. Additionally, threaded fasteners are inserted around the perimeter of the reinforcement pad and into the alignment plate to further secure the alignment plate to the core barrel. A fillet weld also is deposited around the perimeter of the reinforcement pad. To accomodate thermal growth between the alignment plate and the core barrel, a gap is left above, below and at both sides of one of the dowel pins in the alignment plate holes through with the dowel pins pass.

  1. Transport simulation for EBT reactor

    Energy Technology Data Exchange (ETDEWEB)

    Uckan, T.; Uckan, N.A.; Jaeger, E.F.

    1983-08-01

    Transport simulation and modeling studies for the ELMO Bumpy Torus (EBT) reactor are carried out by using zero-dimensional (0-D) and one-and-one-half-dimensional (1 1/2-D) transport calculations. The time-dependent 0-D model is used for global analysis, whereas the 1 1/2-D radial transport code is used for accurate determination of density, temperature, and ambipolar potential profiles and of the role of these profiles in reactor plasma performance. Analysis with the 1 1/2-D transport code shows that profile effects near the outer edge of the hot electron ring lead to enhanced confinement by at least a factor of 2 to 5 beyond the simple scaling that is obtained from the global analysis. The radial profiles of core plasma density and temperatures (or core pressure) obtained from 1 1/2-D transport calculations are found to be similar to those theoretically required for stability.

  2. Gas-liquid autoxidation reactors

    Energy Technology Data Exchange (ETDEWEB)

    Morbidelli, M.; Paludetto, R.; Carra, S.

    1986-01-01

    A procedure for the simulation of autoxidation gas-liquid reactors has been developed based both on mathematical models and laboratory experiments. It has been shown that the complex radical chain mechanism of the autoxidation process can be simulated through two global parallel reactions, whose rates are obtained by assuming pseudo-steady-state concentration values for all the radical species involved. Using ethylbenzene autoxidation as a model reaction, an experimental analysis has been performed in order to estimate all the kinetic parameters of the model. The effect of the interaction between gas-liquid mass-transfer phenomena and the complex kinetic mechanism on the overall performance of an autoxidation reactor has been examined in detail within the framework of the liquid film model.

  3. Fast breeder reactor protection system

    Science.gov (United States)

    van Erp, J.B.

    1973-10-01

    Reactor protection is provided for a liquid-metal-fast breeder reactor core by measuring the coolant outflow temperature from each of the subassemblies of the core. The outputs of the temperature sensors from a subassembly region of the core containing a plurality of subassemblies are combined in a logic circuit which develops a scram alarm if a predetermined number of the sensors indicate an over temperature condition. The coolant outflow from a single subassembly can be mixed with the coolant outflow from adjacent subassemblies prior to the temperature sensing to increase the sensitivity of the protection system to a single subassembly failure. Coherence between the sensors can be required to discriminate against noise signals. (Official Gazette)

  4. Reactor vessel lower head integrity

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, A.M.

    1997-02-01

    On March 28, 1979, the Three Mile Island Unit 2 (TMI-2) nuclear power plant underwent a prolonged small break loss-of-coolant accident that resulted in severe damage to the reactor core. Post-accident examinations of the TMI-2 reactor core and lower plenum found that approximately 19,000 kg (19 metric tons) of molten material had relocated onto the lower head of the reactor vessel. Results of the OECD TMI-2 Vessel Investigation Project concluded that a localized hot spot of approximately 1 meter diameter had existed on the lower head. The maximum temperature on the inner surface of the reactor pressure vessel (RPV) in this region reached 1100{degrees}C and remained at that temperature for approximately 30 minutes before cooling occurred. Even under the combined loads of high temperature and high primary system pressure, the TMI-2 RPV did not fail. (i.e. The pressure varied from about 8.5 to 15 MPa during the four-hour period following the relocation of melt to the lower plenum.) Analyses of RPV failure under these conditions, using state-of-the-art computer codes, predicted that the RPV should have failed via local or global creep rupture. However, the vessel did not fail; and it has been hypothesized that rapid cooling of the debris and the vessel wall by water that was present in the lower plenum played an important role in maintaining RPV integrity during the accident. Although the exact mechanism(s) of how such cooling occurs is not known, it has been speculated that cooling in a small gap between the RPV wall and the crust, and/or in cracks within the debris itself, could result in sufficient cooling to maintain RPV integrity. Experimental data are needed to provide the basis to better understand these phenomena and improve models of RPV failure in severe accident codes.

  5. The ARIES tokamak reactor study

    Energy Technology Data Exchange (ETDEWEB)

    1989-10-01

    The ARIES study is a community effort to develop several visions of tokamaks as fusion power reactors. The aims are to determine the potential economics, safety, and environmental features of a range of possible tokamak reactors, and to identify physics and technology areas with the highest leverage for achieving the best tokamak reactor. Three ARIES visions are planned, each having a different degree of extrapolation from the present data base in physics and technology. The ARIES-I design assumes a minimum extrapolation from current tokamak physics (e.g., 1st stability) and incorporates technological advances that can be available in the next 20 to 30 years. ARIES-II is a DT-burning tokamak which would operate at a higher beta in the 2nd MHD stability regime. It employs both potential advances in the physics and expected advances in technology and engineering. ARIES-II will examine the potential of the tokamak and the D{sup 3}He fuel cycle. This report is a collection of 14 papers on the results of the ARIES study which were presented at the IEEE 13th Symposium on Fusion Engineering (October 2-6, 1989, Knoxville, TN). This collection describes the ARIES research effort, with emphasis on the ARIES-I design, summarizing the major results, the key technical issues, and the central conclusions.

  6. Actinide transmutation in nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Bultman, J.H.

    1995-01-17

    An optimization method is developed to maximize the burning capability of the ALMR while complying with all constraints imposed on the design for reliability and safety. This method leads to a maximal transuranics enrichment, which is being limited by constraints on reactivity. The enrichment can be raised by using the neutrons less efficiently by increasing leakage from the fuel. With the developed optimization method, a metallic and an oxide fueled ALMR were optimized. Both reactors perform equally well considering the burning of transuranics. However, metallic fuel has a much higher heat conductivity coefficient, which in general leads to better safety characteristics. In search of a more effective waste transmuter, a modified Molten Salt Reactor was designed. A MSR operates on a liquid fuel salt which makes continuous refueling possible, eliminating the issue of the burnup reactivity loss. Also, a prompt negative reactivity feedback is possible for an overmoderated reactor design, even when the Doppler coefficient is positive, due to the fuel expansion with fuel temperature increase. Furthermore, the molten salt fuel can be reprocessed based on a reduction process which is not sensitive to the short-lived spontaneously fissioning actinides. (orig./HP).

  7. Assessment of the thorium fuel cycle in power reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kasten, P.R.; Homan, F.J.; Allen, E.J.

    1977-01-01

    A study was conducted at Oak Ridge National Laboratory to evaluate the role of thorium fuel cycles in power reactors. Three thermal reactor systems were considered: Light Water Reactors (LWRs); High-Temperature Gas-Cooled Reactors (HTGRs); and Heavy Water Reactors (HWRs) of the Canadian Deuterium Uranium Reactor (CANDU) type; most of the effort was on these systems. A summary comparing thorium and uranium fuel cycles in Fast Breeder Reactors (FBRs) was also compiled.

  8. Investigation of molten salt fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kubota, Kenichi; Konomura, Mamoru [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan)

    2002-05-01

    On survey research for practicability strategy of fast reactor (FR) (phase 1), to extract future practicability image candidates of FR from wide options, in addition to their survey and investigation objects of not only solid fuel reactors of conventional research object but also molten salt reactor as a flowing fuel reactor, investigation on concept of molten salt FR plant was carried out. As a part of the first step of the survey research for practicability strategy, a basic concept on plant centered at nuclear reactor facility using chloride molten salt reactor capable of carrying out U-Pu cycle was examined, to perform a base construction to evaluate economical potential for a practical FBR. As a result, a result could be obtained that because of inferior fuel inventory and heat transmission to those in Na cooling reactor in present knowledge, mass of reactor vessel and intermediate heat exchanger were to widely increased to expect reduction of power generation unit price even on considering cheapness of its fuel cycle cost. Therefore, at present step further investigation on concept design of the chloride molten salt reactor plant system is too early in time, and it is at a condition where basic and elementary researches aiming at upgrading of economical efficiency such as wide reduction of fuel inventory, a measure expectable for remarkable rationalization effect of reprocessing system integrating a reactor to a processing facility, and so on. (G.K.)

  9. Molten-Salt Depleted-Uranium Reactor

    CERN Document Server

    Dong, Bao-Guo; Gu, Ji-Yuan

    2015-01-01

    The supercritical, reactor core melting and nuclear fuel leaking accidents have troubled fission reactors for decades, and greatly limit their extensive applications. Now these troubles are still open. Here we first show a possible perfect reactor, Molten-Salt Depleted-Uranium Reactor which is no above accident trouble. We found this reactor could be realized in practical applications in terms of all of the scientific principle, principle of operation, technology, and engineering. Our results demonstrate how these reactors can possess and realize extraordinary excellent characteristics, no prompt critical, long-term safe and stable operation with negative feedback, closed uranium-plutonium cycle chain within the vessel, normal operation only with depleted-uranium, and depleted-uranium high burnup in reality, to realize with fission nuclear energy sufficiently satisfying humanity long-term energy resource needs, as well as thoroughly solve the challenges of nuclear criticality safety, uranium resource insuffic...

  10. Performance of a multipurpose research electrochemical reactor

    Energy Technology Data Exchange (ETDEWEB)

    Henquin, E.R. [Programa de Electroquimica Aplicada e Ingenieria Electroquimica (PRELINE), Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2829, S3000AOM Santa Fe (Argentina); Bisang, J.M., E-mail: jbisang@fiq.unl.edu.ar [Programa de Electroquimica Aplicada e Ingenieria Electroquimica (PRELINE), Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2829, S3000AOM Santa Fe (Argentina)

    2011-07-01

    Highlights: > For this reactor configuration the current distribution is uniform. > For this reactor configuration with bipolar connection the leakage current is small. > The mass-transfer conditions are closely uniform along the electrode. > The fluidodynamic behaviour can be represented by the dispersion model. > This reactor represents a suitable device for laboratory trials. - Abstract: This paper reports on a multipurpose research electrochemical reactor with an innovative design feature, which is based on a filter press arrangement with inclined segmented electrodes and under a modular assembly. Under bipolar connection, the fraction of leakage current is lower than 4%, depending on the bipolar Wagner number, and the current distribution is closely uniform. When a turbulence promoter is used, the local mass-transfer coefficient shows a variation of {+-}10% with respect to its mean value. The fluidodynamics of the reactor responds to the dispersion model with a Peclet number higher than 10. It is concluded that this reactor is convenient for laboratory research.

  11. Sulfide toxicity kinetics of a uasb reactor

    Directory of Open Access Journals (Sweden)

    D. R. Paula Jr.

    2009-12-01

    Full Text Available The effect of sulfide toxicity on kinetic parameters of anaerobic organic matter removal in a UASB (up-flow anaerobic sludge blanket reactor is presented. Two lab-scale UASB reactors (10.5 L were operated continuously during 12 months. The reactors were fed with synthetic wastes prepared daily using glucose, ammonium acetate, methanol and nutrient solution. One of the reactors also received increasing concentrations of sodium sulfide. For both reactors, the flow rate of 16 L.d-1 was held constant throughout the experiment, corresponding to a hydraulic retention time of 15.6 hours. The classic model for non-competitive sulfide inhibition was applied to the experimental data for determining the overall kinetic parameter of specific substrate utilization (q and the sulfide inhibition coefficient (Ki. The application of the kinetic parameters determined allows prediction of methanogenesis inhibition and thus the adoption of operating parameters to minimize sulfide toxicity in UASB reactors.

  12. Introduction to the neutron kinetics of nuclear power reactors

    CERN Document Server

    Tyror, J G; Grant, P J

    2013-01-01

    An Introduction to the Neutron Kinetics of Nuclear Power Reactors introduces the reader to the neutron kinetics of nuclear power reactors. Topics covered include the neutron physics of reactor kinetics, feedback effects, water-moderated reactors, fast reactors, and methods of plant control. The reactor transients following faults are also discussed, along with the use of computers in the study of power reactor kinetics. This book is comprised of eight chapters and begins with an overview of the reactor physics characteristics of a nuclear power reactor and their influence on system design and

  13. Microstructured reactors for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Aartun, Ingrid

    2005-07-01

    Small scale hydrogen production by partial oxidation (POX) and oxidative steam reforming (OSR) have been studied over Rh-impregnated microchannel Fecralloy reactors and alumina foams. Trying to establish whether metallic microchannel reactors have special advantages for hydrogen production via catalytic POX or OSR with respect to activity, selectivity and stability was of special interest. The microchannel Fecralloy reactors were oxidised at 1000 deg C to form a {alpha}-Al2O3 layer in the channels in order to enhance the surface area prior to impregnation. Kr-BET measurements showed that the specific surface area after oxidation was approximately 10 times higher than the calculated geometric surface area. Approximately 1 mg Rh was deposited in the channels by impregnation with an aqueous solution of RhCl3. Annular pieces (15 mm o.d.,4 mm i.d., 14 mm length) of extruded {alpha}-Al2O3 foams were impregnated with aqueous solutions of Rh(NO3)3 to obtain 0.01, 0.05 and 0.1 wt.% loadings, as predicted by solution uptake. ICP-AES analyses showed that the actual Rh loadings probably were higher, 0.025, 0.077 and 0.169 wt.% respectively. One of the microchannel Fecralloy reactors and all Al2O3 foams were equipped with a channel to allow for temperature measurement inside the catalytic system. Temperature profiles obtained along the reactor axes show that the metallic microchannel reactor is able to minimize temperature gradients as compared to the alumina foams. At sufficiently high furnace temperature, the gas phase in front of the Rh/Al2O3/Frecralloy microchannel reactor and the 0.025 wt.% Rh/Al2O3 foams ignites. Gas phase ignition leads to lower syngas selectivity and higher selectivity to total oxidation products and hydrocarbon by-products. Before ignition of the gas phase the hydrogen selectivity is increased in OSR as compared to POX, the main contribution being the water-gas shift reaction. After gas phase ignition, increased formation of hydrocarbon by

  14. Plasma spark discharge reactor and durable electrode

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young I.; Cho, Daniel J.; Fridman, Alexander; Kim, Hyoungsup

    2017-01-10

    A plasma spark discharge reactor for treating water. The plasma spark discharge reactor comprises a HV electrode with a head and ground electrode that surrounds at least a portion of the HV electrode. A passage for gas may pass through the reactor to a location proximate to the head to provide controlled formation of gas bubbles in order to facilitate the plasma spark discharge in a liquid environment.

  15. Experimental Breeder Reactor I Preservation Plan

    Energy Technology Data Exchange (ETDEWEB)

    Julie Braun

    2006-10-01

    Experimental Breeder Reactor I (EBR I) is a National Historic Landmark located at the Idaho National Laboratory, a Department of Energy laboratory in southeastern Idaho. The facility is significant for its association and contributions to the development of nuclear reactor testing and development. This Plan includes a structural assessment of the interior and exterior of the EBR I Reactor Building from a preservation, rather than an engineering stand point and recommendations for maintenance to ensure its continued protection.

  16. Reactor Bolshoi Moshchnosti Kalani; Reacteurs RBMK

    Energy Technology Data Exchange (ETDEWEB)

    Bastien, D. [Conservatoire National des Arts et Metiers (CNAM), 75 - Paris (France)

    2000-01-01

    The Reactor Bolshoi Molshchnosti Kalani (RBMK) are pressure tubes reactor, boiling light water cooled. Exported since 1990 from the ex-USSR, they are today in three independent countries: Russian, Ukraine and Lithuania. Since this date, data exchange with the occident allowed the better knowledge of this reactor type. The design, the technical description (core, fuel, primary system), the safety and the improvement since Chernobyl are detailed. (A.L.B.)

  17. NASA Reactor Facility Hazards Summary. Volume 1

    Science.gov (United States)

    1959-01-01

    The Lewis Research Center of the National Aeronautics and Space Administration proposes to build a nuclear research reactor which will be located in the Plum Brook Ordnance Works near Sandusky, Ohio. The purpose of this report is to inform the Advisory Committee on Reactor Safeguards of the U. S. Atomic Energy Commission in regard to the design Lq of the reactor facility, the characteristics of the site, and the hazards of operation at this location. The purpose of this research reactor is to make pumped loop studies of aircraft reactor fuel elements and other reactor components, radiation effects studies on aircraft reactor materials and equipment, shielding studies, and nuclear and solid state physics experiments. The reactor is light water cooled and moderated of the MTR-type with a primary beryllium reflector and a secondary water reflector. The core initially will be a 3 by 9 array of MTR-type fuel elements and is designed for operation up to a power of 60 megawatts. The reactor facility is described in general terms. This is followed by a discussion of the nuclear characteristics and performance of the reactor. Then details of the reactor control system are discussed. A summary of the site characteristics is then presented followed by a discussion of the larger type of experiments which may eventually be operated in this facility. The considerations for normal operation are concluded with a proposed method of handling fuel elements and radioactive wastes. The potential hazards involved with failures or malfunctions of this facility are considered in some detail. These are examined first from the standpoint of preventing them or minimizing their effects and second from the standpoint of what effect they might have on the reactor facility staff and the surrounding population. The most essential feature of the design for location at the proposed site is containment of the maximum credible accident.

  18. Heat for industry from nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kikoin, I.K.; Novikov, V.M.

    Two factors which incline nations toward the use of heat from nuclear reactors for industrial use are: 1) exhaustion of cheap fossil fuel resources, and 2) ecological problems associated both with extraction of fossil fuel from the earth and with its combustion. In addition to the usual problems that beset nuclear reactors, special problems associated with using heat from nuclear reactors in various industries are explored.

  19. D-D tokamak reactor studies

    Energy Technology Data Exchange (ETDEWEB)

    Evans, K.E. Jr.; Baker, C.C.; Brooks, J.N.; Ehst, D.A.; Finn, P.A.; Jung, J.; Mattas, R.F.; Misra, B.; Smith, D.L.; Stevens, H.C.

    1980-11-01

    A tokamak D-D reactor design, utilizing the advantages of a deuterium-fueled reactor but with parameters not unnecessarily extended from existing D-T designs, is presented. Studies leading to the choice of a design and initial studies of the design are described. The studies are in the areas of plasma engineering, first-wall/blanket/shield design, magnet design, and tritium/fuel/vacuum requirements. Conclusions concerning D-D tokamak reactors are stated.

  20. Initiating Events for Multi-Reactor Plant Sites

    Energy Technology Data Exchange (ETDEWEB)

    Muhlheim, Michael David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Flanagan, George F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Poore, III, Willis P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-09-01

    Inherent in the design of modular reactors is the increased likelihood of events that initiate at a single reactor affecting another reactor. Because of the increased level of interactions between reactors, it is apparent that the Probabilistic Risk Assessments (PRAs) for modular reactor designs need to specifically address the increased interactions and dependencies.

  1. High Performance Photocatalytic Oxidation Reactor System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Pioneer Astronautics proposes a technology program for the development of an innovative photocatalytic oxidation reactor for the removal and mineralization of...

  2. Savannah River Site reactor safety assessment. Draft

    Energy Technology Data Exchange (ETDEWEB)

    Woody, N.D.; Brandyberry, M.D. [eds.] [Westinghouse Savannah River Co., Aiken, SC (United States); Baker, W.H.; Brandyberry, M.D.; Kearnaghan, D.P.; O`Kula, K.R.; Woody, N.D. [Westinghouse Savannah River Co., Aiken, SC (United States); Amos, C.N.; Weingardt, J.J. [Science Applications International Corp., San Diego, CA (United States)

    1991-02-28

    This report gives the results of a Savannah River Site (SRS) Production Reactor risk assessment. Measures of adverse consequences to health and safety resulting from representations of severe accidents in SRS reactors are presented. In addition, the report gives a summary of the methods employed to represent these accidents and to assess the resultant consequences. The report is issued to provide timely information to the US Department of Energy (DOE) on the risk of operation of SRS reactors, for insights into severe accident phenomena that contribute to this risk, and in support of improved bases for other Site programs in Heavy Water Reactor safety.

  3. History of fast reactor fuel development

    Energy Technology Data Exchange (ETDEWEB)

    Kittel, J.H.; Frost, B.R.T. (Argonne National Lab., IL (United States)); Mustelier, J.P. (COGEMA, Velizy-Villacoublay (France))

    1992-01-01

    Most of the first generation of fast reactors that were operated at significant power levels employed solid metal fuels. They were constructed in the United States and United Kingdom in the 1950s and included Experimental Breeder Reactor (EBR)-I and -II operated by Argonne National Laboratory, United States, the Enrico Fermi Reactor operated by the Atomic Power Development Associates, United States and DFR operated by the U.K. Atomic Energy Authority (UKAEA). Their paper tracer pre-development of fast reactor fuel from these early days through the 1980s including ceramic fuels.

  4. Advanced nuclear reactor types and technologies

    Energy Technology Data Exchange (ETDEWEB)

    Ignatiev, V. [ed.; Feinberg, O.; Morozov, A. [Russian Research Centre `Kurchatov Institute`, Moscow (Russian Federation); Devell, L. [Studsvik Eco and Safety AB, Nykoeping (Sweden)

    1995-07-01

    The document is a comprehensive world-wide catalogue of concepts and designs of advanced fission reactor types and fuel cycle technologies. Two parts have been prepared: Part 1 Reactors for Power Production and Part 2 Heating and Other Reactor Applications. Part 3, which will cover advanced waste management technology, reprocessing and disposal for different nuclear fission options is planned for compilation during 1995. The catalogue was prepared according to a special format which briefly presents the project title, technical approach, development status, application of the technology, reactor type, power output, and organization which developed these designs. Part 1 and 2 cover water cooled reactors, liquid metal fast reactors, gas-cooled reactors and molten salt reactors. Subcritical accelerator-driven systems are also considered. Various reactor applications as power production, heat generation, ship propulsion, space power sources and transmutation of such waste are included. Each project is described within a few pages with the main features of an actual design using a table with main technical data and figure as well as references for additional information. Each chapter starts with an introduction which briefly describes main trends and approaches in this field. Explanations of terms and abbreviations are provided in a glossary.

  5. Supercritical-pressure light water cooled reactors

    CERN Document Server

    Oka, Yoshiaki

    2014-01-01

    This book focuses on the latest reactor concepts, single pass core and experimental findings in thermal hydraulics, materials, corrosion, and water chemistry. It highlights research on supercritical-pressure light water cooled reactors (SCWRs), one of the Generation IV reactors that are studied around the world. This book includes cladding material development and experimental findings on heat transfer, corrosion and water chemistry. The work presented here will help readers to understand the fundamental elements of reactor design and analysis methods, thermal hydraulics, materials and water

  6. Sandia National Laboratories Medical Isotope Reactor concept.

    Energy Technology Data Exchange (ETDEWEB)

    Coats, Richard Lee; Dahl, James J.; Parma, Edward J., Jr.

    2010-04-01

    This report describes the Sandia National Laboratories Medical Isotope Reactor and hot cell facility concepts. The reactor proposed is designed to be capable of producing 100% of the U.S. demand for the medical isotope {sup 99}Mo. The concept is novel in that the fuel for the reactor and the targets for the {sup 99}Mo production are the same. There is no driver core required. The fuel pins that are in the reactor core are processed on a 7 to 21 day irradiation cycle. The fuel is low enriched uranium oxide enriched to less than 20% {sup 235}U. The fuel pins are approximately 1 cm in diameter and 30 to 40 cm in height, clad with Zircaloy (zirconium alloy). Approximately 90 to 150 fuel pins are arranged in the core in a water pool {approx}30 ft deep. The reactor power level is 1 to 2 MW. The reactor concept is a simple design that is passively safe and maintains negative reactivity coefficients. The total radionuclide inventory in the reactor core is minimized since the fuel/target pins are removed and processed after 7 to 21 days. The fuel fabrication, reactor design and operation, and {sup 99}Mo production processing use well-developed technologies that minimize the technological and licensing risks. There are no impediments that prevent this type of reactor, along with its collocated hot cell facility, from being designed, fabricated, and licensed today.

  7. NCSU reactor sharing program. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Perez, P.B.

    1997-01-10

    The Nuclear Reactor Program at North Carolina State University provides the PULSTAR Research Reactor and associated facilities to eligible institutions with support, in part, from the Department of Energy Reactor Sharing Program. Participation in the NCSU Reactor Sharing Program continues to increase steadily with visitors ranging from advance high school physics and chemistry students to Ph.D. level research from neighboring universities. This report is the Final Technical Report for the DOE award reference number DE-FG05-95NE38136 which covers the period September 30, 1995 through September 30, 1996.

  8. Molecular ecology of anaerobic reactor systems

    DEFF Research Database (Denmark)

    Hofman-Bang, H. Jacob Peider; Zheng, D.; Westermann, Peter;

    2003-01-01

    Anaerobic reactor systems are essential for the treatment of solid and liquid wastes and constitute a core facility in many waste treatment plants. Although much is known about the basic metabolism in different types of anaerobic reactors, little is known about the microbes responsible...... to the abundance of each microbe in anaerobic reactor systems by rRNA probing. This chapter focuses on various molecular techniques employed and problems encountered when elucidating the microbial ecology of anaerobic reactor systems. Methods such as quantitative dot blot/fluorescence in-situ probing using various...

  9. Advances in light water reactor technologies

    CERN Document Server

    Saito, Takehiko; Ishiwatari, Yuki; Oka, Yoshiaki

    2010-01-01

    ""Advances in Light Water Reactor Technologies"" focuses on the design and analysis of advanced nuclear power reactors. This volume provides readers with thorough descriptions of the general characteristics of various advanced light water reactors currently being developed worldwide. Safety, design, development and maintenance of these reactors is the main focus, with key technologies like full MOX core design, next-generation digital I&C systems and seismic design and evaluation described at length. This book is ideal for researchers and engineers working in nuclear power that are interested

  10. Nanostructured Catalytic Reactors for Air Purification Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I project proposes the development of lightweight compact nanostructured catalytic reactors for air purification from toxic gaseous organic...

  11. Phosphorus removal in aerated stirred tank reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ghigliazza, R.; Lodi, A.; Rovatti, M. [Inst. of Chemical and Process Engineering ``G.B. Bonino``, Univ. of Genoa (Italy)

    1999-03-01

    The possibility to obtain biological phosphorus removal in strictly aerobic conditions has been investigated. Experiments, carried out in a continuous stirred tank reactor (CSTR), show the feasibility to obtain phosphorus removal without the anaerobic phase. Reactor performance in terms of phosphorus abatement kept always higher then 65% depending on adopted sludge retention time (SRT). In fact increasing SRT from 5 days to 8 days phosphorus removal and reactor performance increase but overcoming this SRT value a decreasing in reactor efficiency was recorded. (orig.) With 6 figs., 3 tabs., 18 refs.

  12. Sodium fast reactors with closed fuel cycle

    CERN Document Server

    Raj, Baldev; Vasudeva Rao, PR 0

    2015-01-01

    Sodium Fast Reactors with Closed Fuel Cycle delivers a detailed discussion of an important technology that is being harnessed for commercial energy production in many parts of the world. Presenting the state of the art of sodium-cooled fast reactors with closed fuel cycles, this book:Offers in-depth coverage of reactor physics, materials, design, safety analysis, validations, engineering, construction, and commissioning aspectsFeatures a special chapter on allied sciences to highlight advanced reactor core materials, specialized manufacturing technologies, chemical sensors, in-service inspecti

  13. Autonomous Control of Space Nuclear Reactors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Nuclear reactors to support future robotic and manned missions impose new and innovative technological requirements for their control and protection instrumentation....

  14. Neutron imaging on the VR-1 reactor

    Science.gov (United States)

    Crha, J.; Sklenka, L.; Soltes, J.

    2016-09-01

    Training reactor VR-1 is a low power research reactor with maximal thermal power of 1 kW. The reactor is operated by the Faculty of Nuclear Science and Physical Engineering of the Czech Technical University in Prague. Due to its low power it suits as a tool for education of university students and training of professionals. In 2015, as part of student research project, neutron imaging was introduced as another type of reactor utilization. The low available neutron flux and the limiting spatial and construction capabilities of the reactor's radial channel led to the development of a special filter/collimator insertion inside the channel and choosing a nonstandard approach by placing a neutron imaging plate inside the channel. The paper describes preliminary experiments carried out on the VR-1 reactor which led to first radiographic images. It seems, that due to the reactor construction and low reactor power, the neutron imaging technique on the VR-1 reactor is feasible mainly for demonstration or educational and training purposes.

  15. Microchannel Methanation Reactors Using Nanofabricated Catalysts Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering, Inc. (MEI) and the Pennsylvania State University (Penn State) propose to develop and demonstrate a microchannel methanation reactor based on...

  16. Nanostructured Catalytic Reactors for Air Purification Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase II project proposes the development of lightweight compact nanostructured catalytic reactors for air purification from toxic gaseous organic...

  17. Continuous steroid biotransformations in microchannel reactors.

    Science.gov (United States)

    Marques, Marco P C; Fernandes, Pedro; Cabral, Joaquim M S; Znidaršič-Plazl, Polona; Plazl, Igor

    2012-01-15

    The use of microchannel reactor based technologies within the scope of bioprocesses as process intensification and production platforms is gaining momentum. Such trend can be ascribed a particular set of characteristics of microchannel reactors, namely the enhanced mass and heat transfer, combined with easier handling and smaller volumes required, as compared to traditional reactors. In the present work, a continuous production process of 4-cholesten-3-one by the enzymatic oxidation of cholesterol without the formation of any by-product was assessed. The production was carried out within Y-shaped microchannel reactors in an aqueous-organic two-phase system. Substrate was delivered from the organic phase to aqueous phase containing cholesterol oxidase and the product formed partitions back to the organic phase. The aqueous phase was then forced through a plug-flow reactor, containing immobilized catalase. This step aimed at the reduction of hydrogen peroxide formed as a by-product during cholesterol oxidation, to avoid cholesterol oxidase deactivation due to said by-product. This setup was compared with traditional reactors and modes of operation. The results showed that microchannel reactor geometry outperformed traditional stirred tank and plug-flow reactors reaching similar conversion yields at reduced residence time. Coupling the plug-flow reactor containing catalase enabled aqueous phase reuse with maintenance of 30% catalytic activity of cholesterol oxidase while eliminating hydrogen peroxide. A final production of 36 m of cholestenone was reached after 300 hours of operation.

  18. Reactors for nuclear electric propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Buden, D.; Angelo, J.A. Jr.

    1981-01-01

    Propulsion is the key to space exploitation and power is the key to propulsion. This paper examines the role of nuclear fission reactors as the primary power source for high specific impulse electric propulsion systems for space missions of the 1980s and 1990s. Particular mission applications include transfer to and a reusable orbital transfer vehicle from low-Earth orbit to geosynchronous orbit, outer planet exploration and reconnaissance missions, and as a versatile space tug supporting lunar resource development. Nuclear electric propulsion is examined as an indispensable component in space activities of the next two decades.

  19. Biodegradation of MTBE in reactors

    DEFF Research Database (Denmark)

    Waul, Christopher Kevin

    2007-01-01

    The fuel oxygenate methyl tert-butyl ether (MTBE) was first introduced in the 1970’s to improve gasoline combustion efficiency and reduce emission of harmful gases. However, it has caused groundwater contamination in Denmark and in many locations worldwide through accidental releases from leaking...... such as ammonium or benzene, toluene, ethyl benzene and xylene (BTEX) oxidizers, which can be present together in a single system. The competition resulted in reduced and/or delayed degradation of MTBE when there were limitations of oxygen or space in the reactor. The fraction of biologically active (BA) MTBE...

  20. Bidirectional regulation of the cAMP response element binding protein encodes spatial map alignment in prism-adapting barn owls.

    Science.gov (United States)

    Nichols, Grant S; DeBello, William M

    2008-10-01

    The barn owl midbrain contains mutually aligned maps of auditory and visual space. Throughout life, map alignment is maintained through the actions of an instructive signal that encodes the magnitude of auditory-visual mismatch. The intracellular signaling pathways activated by this signal are unknown. Here we tested the hypothesis that CREB (cAMP response element-binding protein) provides a cell-specific readout of instructive information. Owls were fitted with prismatic or control spectacles and provided rich auditory-visual experience: hunting live mice. CREB activation was analyzed within 30 min of hunting using phosphorylation state-specific CREB (pCREB) and CREB antibodies, confocal imaging, and immunofluorescence measurements at individual cell nuclei. In control owls or prism-adapted owls, which experience small instructive signals, the frequency distributions of pCREB/CREB values obtained for cell nuclei within the external nucleus of the inferior colliculus (ICX) were unimodal. In contrast, in owls adapting to prisms or readapting to normal conditions, the distributions were bimodal: certain cells had received a signal that positively regulated CREB and, by extension, transcription of CREB-dependent genes, whereas others received a signal that negatively regulated it. These changes were restricted to the subregion of the inferior colliculus that received optically displaced input, the rostral ICX, and were not evident in the caudal ICX or central nucleus. Finally, the topographic pattern of CREB regulation was patchy, not continuous, as expected from the actions of a topographically precise signal encoding discrete events. These results support a model in which the magnitude of CREB activation within individual cells provides a readout of the instructive signal that guides plasticity and learning.

  1. 5-HTT deficiency affects neuroplasticity and increases stress sensitivity resulting in altered spatial learning performance in the Morris water maze but not in the Barnes maze.

    Directory of Open Access Journals (Sweden)

    Margherita M Karabeg

    Full Text Available The purpose of this study was to evaluate whether spatial hippocampus-dependent learning is affected by the serotonergic system and stress. Therefore, 5-HTT knockout (-/-, heterozygous (+/- and wildtype (+/+ mice were subjected to the Barnes maze (BM and the Morris water maze (WM, the latter being discussed as more aversive. Additionally, immediate early gene (IEG expression, hippocampal adult neurogenesis (aN, and blood plasma corticosterone were analyzed. While the performance of 5-HTT-/- mice in the BM was undistinguishable from both other genotypes, they performed worse in the WM. However, in the course of the repeated WM trials 5-HTT-/- mice advanced to wildtype level. The experience of a single trial of either the WM or the BM resulted in increased plasma corticosterone levels in all genotypes. After several trials 5-HTT-/- mice exhibited higher corticosterone concentrations compared with both other genotypes in both tests. Corticosterone levels were highest in 5-HTT-/- mice tested in the WM indicating greater aversiveness of the WM and a greater stress sensitivity of 5-HTT deficient mice. Quantitative immunohistochemistry in the hippocampus revealed increased cell counts positive for the IEG products cFos and Arc as well as for proliferation marker Ki67 and immature neuron marker NeuroD in 5-HTT-/- mice compared to 5-HTT+/+ mice, irrespective of the test. Most differences were found in the suprapyramidal blade of the dentate gyrus of the septal hippocampus. Ki67-immunohistochemistry revealed a genotype x environment interaction with 5-HTT genotype differences in naïve controls and WM experience exclusively yielding more Ki67-positive cells in 5-HTT+/+ mice. Moreover, in 5-HTT-/- mice we demonstrate that learning performance correlates with the extent of aN. Overall, higher baseline IEG expression and increased an in the hippocampus of 5-HTT-/- mice together with increased stress sensitivity may constitute the neurobiological correlate of

  2. 5-HTT deficiency affects neuroplasticity and increases stress sensitivity resulting in altered spatial learning performance in the Morris water maze but not in the Barnes maze.

    Science.gov (United States)

    Karabeg, Margherita M; Grauthoff, Sandra; Kollert, Sina Y; Weidner, Magdalena; Heiming, Rebecca S; Jansen, Friederike; Popp, Sandy; Kaiser, Sylvia; Lesch, Klaus-Peter; Sachser, Norbert; Schmitt, Angelika G; Lewejohann, Lars

    2013-01-01

    The purpose of this study was to evaluate whether spatial hippocampus-dependent learning is affected by the serotonergic system and stress. Therefore, 5-HTT knockout (-/-), heterozygous (+/-) and wildtype (+/+) mice were subjected to the Barnes maze (BM) and the Morris water maze (WM), the latter being discussed as more aversive. Additionally, immediate early gene (IEG) expression, hippocampal adult neurogenesis (aN), and blood plasma corticosterone were analyzed. While the performance of 5-HTT-/- mice in the BM was undistinguishable from both other genotypes, they performed worse in the WM. However, in the course of the repeated WM trials 5-HTT-/- mice advanced to wildtype level. The experience of a single trial of either the WM or the BM resulted in increased plasma corticosterone levels in all genotypes. After several trials 5-HTT-/- mice exhibited higher corticosterone concentrations compared with both other genotypes in both tests. Corticosterone levels were highest in 5-HTT-/- mice tested in the WM indicating greater aversiveness of the WM and a greater stress sensitivity of 5-HTT deficient mice. Quantitative immunohistochemistry in the hippocampus revealed increased cell counts positive for the IEG products cFos and Arc as well as for proliferation marker Ki67 and immature neuron marker NeuroD in 5-HTT-/- mice compared to 5-HTT+/+ mice, irrespective of the test. Most differences were found in the suprapyramidal blade of the dentate gyrus of the septal hippocampus. Ki67-immunohistochemistry revealed a genotype x environment interaction with 5-HTT genotype differences in naïve controls and WM experience exclusively yielding more Ki67-positive cells in 5-HTT+/+ mice. Moreover, in 5-HTT-/- mice we demonstrate that learning performance correlates with the extent of aN. Overall, higher baseline IEG expression and increased an in the hippocampus of 5-HTT-/- mice together with increased stress sensitivity may constitute the neurobiological correlate of raised

  3. Divorce in the barn owl: securing a compatible or better mate entails the cost of re-pairing with a less ornamented female mate.

    Science.gov (United States)

    Dreiss, A N; Roulin, A

    2014-06-01

    Two nonmutually exclusive hypotheses can explain why divorce is an adaptive strategy to improve reproductive success. Under the 'better option hypothesis', only one of the two partners initiates divorce to secure a higher-quality partner and increases reproductive success after divorce. Under the 'incompatibility hypothesis', partners are incompatible and hence they may both increase reproductive success after divorce. In a long-term study of the barn owl (Tyto alba), we address the question of whether one or the two partners derive fitness benefits by divorcing. Our results support the hypothesis that divorce is adaptive: after a poor reproductive season, at least one of the two divorcees increase breeding success up to the level of faithful pairs. By breeding more often together, faithful pairs improve coordination and thereby gain in their efficiency to produce successful fledglings. Males would divorce to obtain a compatible mate rather than a mate of higher quality: a heritable melanin-based signal of female quality did not predict divorce (indicating that female absolute quality may not be the cause of divorce), but the new mate of divorced males was less melanic than their previous mate. This suggests that, at least for males, a cost of divorce may be to secure a lower-quality but compatible mate. The better option hypothesis could not be formally rejected, as only one of the two divorcing partners commonly succeeded in obtaining a higher reproductive success after divorce. In conclusion, incompatible partners divorce to restore reproductive success, and by breeding more often together, faithful partners improve coordination.

  4. 密集烤房不同装烟方式比较研究%Comparison of Tobacco Leaf Loading Methods in Bulk Curing Barn

    Institute of Scientific and Technical Information of China (English)

    孙曙光; 周童; 顾会战; 彭毅; 汪健; 王鹏; 陈利平

    2012-01-01

    [目的]探索密集烤房的最佳装烟方式.[方法]以密集烤房挂杆方式为对照,比较研究了托架式烟夹、框架散叶、散叶插签装烟方式的配套设备成本、装烟量、用工量、烤后烟叶经济性状、能耗成本等状况.[结果]托架式烟夹、框架散叶、散叶插签装烟方式节能省工效果明显,3种装烟方式装烟量最大可提高71.43%,初烤烟经济性状均有所提高,符合现代烟草农业集约化和可持续发展要求.[结论]研究可为密集烤房不同装烟方式的优化提供参考依据.%[Objective] To explore the best tobacco leaf loading method. [Method] With hang poles as control group, bracket type smoke clamp, framework loose leaf and loose leaf cutting sign loading tobacco patterns were tested in bulk curing barn about corollary equipment cost, pack smoke volume, the employment quantity, roast tobacco leaf after economic characters, energy consumption cost. [Result] The results showed that bracket type smoke clamp, framework loose leaf and loose leaf cutting sign were much better than hang poles in energy and worker saving. Because largest amount of the three tobacco leaf loading method can be increased by 71. 43 % and initial flue-cured tobacco economic characters are improved so they accord with the modern tobacco agriculture. [Conclusion] The study provides reference basis for optimization of different tobacco loading method.

  5. Coupled reactor kinetics and heat transfer model for heat pipe cooled reactors

    Science.gov (United States)

    Wright, Steven A.; Houts, Michael

    2001-02-01

    Heat pipes are often proposed as cooling system components for small fission reactors. SAFE-300 and STAR-C are two reactor concepts that use heat pipes as an integral part of the cooling system. Heat pipes have been used in reactors to cool components within radiation tests (Deverall, 1973); however, no reactor has been built or tested that uses heat pipes solely as the primary cooling system. Heat pipe cooled reactors will likely require the development of a test reactor to determine the main differences in operational behavior from forced cooled reactors. The purpose of this paper is to describe the results of a systems code capable of modeling the coupling between the reactor kinetics and heat pipe controlled heat transport. Heat transport in heat pipe reactors is complex and highly system dependent. Nevertheless, in general terms it relies on heat flowing from the fuel pins through the heat pipe, to the heat exchanger, and then ultimately into the power conversion system and heat sink. A system model is described that is capable of modeling coupled reactor kinetics phenomena, heat transfer dynamics within the fuel pins, and the transient behavior of heat pipes (including the melting of the working fluid). This paper focuses primarily on the coupling effects caused by reactor feedback and compares the observations with forced cooled reactors. A number of reactor startup transients have been modeled, and issues such as power peaking, and power-to-flow mismatches, and loading transients were examined, including the possibility of heat flow from the heat exchanger back into the reactor. This system model is envisioned as a tool to be used for screening various heat pipe cooled reactor concepts, for designing and developing test facility requirements, for use in safety evaluations, and for developing test criteria for in-pile and out-of-pile test facilities. .

  6. Compound cryopump for fusion reactors

    CERN Document Server

    Kovari, M; Shephard, T

    2013-01-01

    We reconsider an old idea: a three-stage compound cryopump for use in fusion reactors such as DEMO. The helium "ash" is adsorbed on a 4.5 K charcoal-coated surface, while deuterium and tritium are adsorbed at 15-22 K on a second charcoal-coated surface. The helium is released by raising the first surface to ~30 K. In a separate regeneration step, deuterium and tritium are released at ~110 K. In this way, the helium can be pre-separated from other species. In the simplest design, all three stages are in the same vessel, with a single valve to close the pump off from the tokamak during regeneration. In an alternative design, the three stages are in separate vessels, connected by valves, allowing the stages to regenerate without interfering with each other. The inclusion of the intermediate stage would not affect the overall pumping speed significantly. The downstream exhaust processing system could be scaled down, as much of the deuterium and tritium could be returned directly to the reactor. This could reduce ...

  7. K-East and K-West Reactors

    Data.gov (United States)

    Federal Laboratory Consortium — Hanford's "sister reactors", the K-East and the K-West Reactors, were built side-by-side in the early 1950's. The two reactors went operational within four months of...

  8. 烤烟密集烤房加装余热采热器节能效果分析%Analysis on Energy Conservation Effect of Tobacco Bulk Curing Barn Retrofitted Waste-heat Collector

    Institute of Scientific and Technical Information of China (English)

    文国宇; 邱妙文; 王行; 黄履明; 何振峰

    2015-01-01

    为了有效降低密集烤房排烟热损失,增加热能利用率,本文以单座密集烤房为研究对象,通过低成本改造加装余热采热器,并与普通密集烤房进行对比试验,分析其节能效果。结果表明,密集烤房加装余热采热器后,烟叶烘烤过程中烟囱排烟口的温度明显降低,降幅达到30%左右,减少了排烟热损失;同时提高了燃煤热能利用率,平均烘烤煤耗降低5.11%,节省了烘烤成本。因此,这是一种针对单座密集烤房群,实现节能的有效途径。%In order to reduce heat loss of flue gases and improve energy efficiency of bulk curing barn, we focus on a single bulk curing barn retrofitted waste-heat collector, and analyses its energy conservation effect comparing with ordinary. The results show that, through transformation, the temperature of chimney outlets has remarkably lowered, a drop of 30%, to cut down smoke heat loss; In the meantime, energy efficiency has greatly improved, reduced coal consumption by an average of 5.11%, to save cost. In conclusion, it is an effective approach to realizing the objective of energy saving for a single bulk curing barn.

  9. 巴基斯坦旁遮普中部仓鸮食性的季节性变化%Seasonal variation in the diet of the barn owl Tyto alba stertens in central Punjab, Pakistan

    Institute of Scientific and Technical Information of China (English)

    Muhammad MAHMOOD-UL-HASSAN; Mirza Azhar BEG; Habib ALI

    2007-01-01

    在巴基斯坦对仓鸮食性的季节变化进行了研究.通过分析连续3年在6个地区搜集的2 360个仓鸮回吐食物团,发现其食物主要是小型哺乳动物(95.6%).其中,家鼩(Suncus murinus)有最高的比例,达65.6%(冬季最多78%,夏季最少27%).就生物量而言,小型哺乳动物占仓鸮食物总生物量的99%[动物学报 53(3):431-436,2007].%Seasonal and climatic changes influence the diet of the barn owl Tyto alba throughout its range. We conducted the first long-term study in Pakistan to understand seasonal changes in the diet of this raptor. Regurgitated pellets (n=2 360) were collected for three years from six districts of central Punjab. An analysis of these pellets revealed that the barn owl depended mainly on small mammals (95.6%) for its food. The house shrew Suncus murinus was the main food item (65.6%) in its diet. It was the most common prey item in winter (78%) and was consumed the least during summer (27%). This seasonal rise and fall in the frequency of shrews in the diet was related to an inverse pattern of rise and fall in the frequency of rodents, birds and bats. Small mammals contributed 99% of the biomass consumed by the barn owl[Acta Zoologica Sinica 53(3):431-436,2007].

  10. A new MTR fuel for a new MTR reactor: UMo for the Jules Horowitz reactor

    Energy Technology Data Exchange (ETDEWEB)

    Guigon, B. [CEA Cadarache, Dir. de l' Energie Nucleaire DEN, Reacteur Jules Horowitz, 13 - Saint-Paul-lez-Durance (France); Vacelet, H. [Compagnie pour l' Etude et la Realisation de Combustibles Atomiques, CERCA, Etablissement de Romans, 26 (France); Dornbusch, D. [Technicatome, Service d' Architecture Generale, 13 - Aix-en-Provence (France)

    2003-07-01

    Within some years, the Jules Horowitz Reactor will be the only working experimental reactor (material and fuel testing reactor) in France. It will have to provide facilities for a wide range of needs: from activation analysis to power reactor fuel qualification. In this paper will be presented the main characteristics of the Jules Horowitz Reactor: its total power, neutron flux, fuel element... Safety criteria will be explained. Finally merits and disadvantages of UMo compared to the standard U{sub 3}Si{sub 2} fuel will be discussed. (authors)

  11. Annual report on JEN-1 reactor; Informe periodico del Reactor JEN-1 correspondiente al ano 1971

    Energy Technology Data Exchange (ETDEWEB)

    Montes, J.

    1972-07-01

    In the annual report on the JEN-1 reactor the main features of the reactor operations and maintenance are described. The reactor has been critical for 1831 hours, what means 65,8% of the total working time. Maintenance and pool water contamination have occupied the rest of the time. The maintenance schedule is shown in detail according to three subjects. The main failures and reactor scrams are also described. The daily maximum values of the water activity are given so as the activity of the air in the reactor hall. (Author)

  12. Selective purge for hydrogenation reactor recycle loop

    Science.gov (United States)

    Baker, Richard W.; Lokhandwala, Kaaeid A.

    2001-01-01

    Processes and apparatus for providing improved contaminant removal and hydrogen recovery in hydrogenation reactors, particularly in refineries and petrochemical plants. The improved contaminant removal is achieved by selective purging, by passing gases in the hydrogenation reactor recycle loop or purge stream across membranes selective in favor of the contaminant over hydrogen.

  13. Radiochemical problems of fusion reactors. 1. Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Crespi, M.B.A.

    1984-02-01

    A list of fusion reactor candidate materials is given, for use in connection with blanket structure, breeding, moderation, neutron multiplication, cooling, magnetic field generation, electrical insulation and radiation shielding. The phenomena being studied for each group of materials are indicated. Suitable irradiation test facilities are discussed under the headings (1) accelerator-based neutron sources, (2) fission reactors, and (3) ion accelerators.

  14. Advanced tokamak concepts and reactor designs

    NARCIS (Netherlands)

    Oomens, A. A. M.

    2000-01-01

    From a discussion of fusion reactor designs based on today's well-established experience gained in the operation of large tokamaks, it is concluded that such reactors are economically not attractive. The physics involved in the various options for concept improvement is described, some examples

  15. Startup of an industrial adiabatic tubular reactor

    NARCIS (Netherlands)

    Verwijs, J.W.; Berg, van den H.; Westerterp, K.R.

    1992-01-01

    The dynamic behaviour of an adiabatic tubular plant reactor during the startup is demonstrated, together with the impact of a feed-pump failure of one of the reactants. A dynamic model of the reactor system is presented, and the system response is calculated as a function of experimentally-determine

  16. Rotor for a pyrolysis centrifuge reactor

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a rotor for a pyrolysis centrifuge reactor, said rotor comprising a rotor body having a longitudinal centre axis, and at least one pivotally mounted blade being adapted to pivot around a pivot axis under rotation of the rotor body around the longitudinal centre axis....... Moreover, the present invention relates to a pyrolysis centrifuge reactor applying such a rotor....

  17. Helix reactor: great potential for flow chemistry

    NARCIS (Netherlands)

    Geerdink, P.; Runstraat, A. van den; Roelands, C.P.M.; Goetheer, E.L.V.

    2009-01-01

    The Helix reactor is highly suited for precise reaction control based on good hydrodynamics. The hydrodynamics are controlled by the Dean vortices, which create excellent heat transfer properties, approach plug flow and avoid turbulence. The flexibility of this reactor has been demonstrated using a

  18. The Design of a Nuclear Reactor

    Indian Academy of Sciences (India)

    2016-09-01

    The aim of this largely pedagogical article is toemploy pre-college physics to arrive at an understanding of a system as complex as a nuclear reactor. We focus on three key issues: the fuelpin, the moderator, and lastly the dimensions ofthe nuclear reactor.

  19. Design of an organic simplified nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Shirvan, Koroush [Dept. of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge (United States); Forrest, Eric [Primary Standards Laboratory, Sandia National Laboratories, Albuquerque (United States)

    2016-08-15

    Numerous advanced reactor concepts have been proposed to replace light water reactors ever since their establishment as the dominant technology for nuclear energy production. While most designs seek to improve cost competitiveness and safety, the implausibility of doing so with affordable materials or existing nuclear fuel infrastructure reduces the possibility of near-term deployment, especially in developing countries. The organic nuclear concept, first explored in the 1950s, offers an attractive alternative to advanced reactor designs being considered. The advent of high temperature fluids, along with advances in hydrocracking and reforming technologies driven by the oil and gas industries, make the organic concept even more viable today. We present a simple, cost-effective, and safe small modular nuclear reactor for offshore underwater deployment. The core is moderated by graphite, zirconium hydride, and organic fluid while cooled by the organic fluid. The organic coolant enables operation near atmospheric pressure and use of plain carbon steel for the reactor tank and primary coolant piping system. The core is designed to mitigate the coolant degradation seen in early organic reactors. Overall, the design provides a power density of 40 kW/L, while reducing the reactor hull size by 40% compared with a pressurized water reactor while significantly reducing capital plant costs.

  20. Technical features of the MR reactor decommissioning

    Directory of Open Access Journals (Sweden)

    Craig David

    2008-01-01

    Full Text Available This paper presents a preliminary technical design for the dismantling of the MR reactor. The goal of the design is the removal of reactor components allowing the re-use of the building for a different nuclear related purpose. The sequence of segmentation procedures is established. Considerations on the size reduction and tooling are presented.

  1. The First Reactor, 40th Anniversary (rev.)

    Energy Technology Data Exchange (ETDEWEB)

    Allardice, Corbin; Trapnell, Edward R; Fermi, Enrico; Fermi, Laura; Williams, Robert C

    1982-12-01

    This booklet, an updated version of the original booklet describing the first nuclear reactor, was written in honor of the 40th anniversary of the first reactor or "pile". It is based on firsthand accounts told to Corbin Allardice and Edward R. Trapnell, and includes recollections of Enrico and Laura Fermi.

  2. MODERATOR ELEMENTS FOR UNIFORM POWER NUCLEAR REACTOR

    Science.gov (United States)

    Balent, R.

    1963-03-12

    This patent describes a method of obtaining a flatter flux and more uniform power generation across the core of a nuclear reactor. The method comprises using moderator elements having differing moderating strength. The elements have an increasing amount of the better moderating material as a function of radial and/or axial distance from the reactor core center. (AEC)

  3. Parametric sensitivity and runaway in tubular reactors

    Energy Technology Data Exchange (ETDEWEB)

    Morbidelli, M.; Varma, A.

    1982-09-01

    Parametric sensitivity of tubular reactors is analyzed to provide critical values of the heat of reaction and heat transfer parameters defining runaway and stable operations for all positive-order exothermic reactions with finite activation energies, and for all reactor inlet temperatures. Evaluation of the critical values does not involve any trial and error.

  4. Microbial degradation of MTBE in reactors

    DEFF Research Database (Denmark)

    Waul, Christopher Kevin; Arvin, Erik; Schmidt, Jens Ejbye

    2007-01-01

    , toluene, ethylbenzene and xylenes, may reduce the removal rates of MTBE, or prevent its removal in reactors. With mathematical modelling, the long startup time required for some MTBE degrading reactors could be predicted. Long startup times of up to 200 days were due to the low maximum growth rate...

  5. Design of an Organic Simplified Nuclear Reactor

    Directory of Open Access Journals (Sweden)

    Koroush Shirvan

    2016-08-01

    Full Text Available Numerous advanced reactor concepts have been proposed to replace light water reactors ever since their establishment as the dominant technology for nuclear energy production. While most designs seek to improve cost competitiveness and safety, the implausibility of doing so with affordable materials or existing nuclear fuel infrastructure reduces the possibility of near-term deployment, especially in developing countries. The organic nuclear concept, first explored in the 1950s, offers an attractive alternative to advanced reactor designs being considered. The advent of high temperature fluids, along with advances in hydrocracking and reforming technologies driven by the oil and gas industries, make the organic concept even more viable today. We present a simple, cost-effective, and safe small modular nuclear reactor for offshore underwater deployment. The core is moderated by graphite, zirconium hydride, and organic fluid while cooled by the organic fluid. The organic coolant enables operation near atmospheric pressure and use of plain carbon steel for the reactor tank and primary coolant piping system. The core is designed to mitigate the coolant degradation seen in early organic reactors. Overall, the design provides a power density of 40 kW/L, while reducing the reactor hull size by 40% compared with a pressurized water reactor while significantly reducing capital plant costs.

  6. Verification of Remote Inspection Techniques for Reactor Internal Structures of Liquid Metal Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Young Sang; Lee, Jae Han

    2007-02-15

    The reactor internal structures and components of a liquid metal reactor (LMR) are submerged in hot sodium of reactor vessel. The division 3 of ASME code section XI specifies the visual inspection as major in-service inspection (ISI) methods of reactor internal structures and components. Reactor internals of LMR can not be visually examined due to opaque liquid sodium. The under-sodium viewing techniques using an ultrasonic wave should be applied for the visual inspection of reactor internals. Recently, an ultrasonic waveguide sensor with a strip plate has been developed for an application to the under-sodium inspection. In this study, visualization technique, ranging technique and monitoring technique have been suggested for the remote inspection of reactor internals by using the waveguide sensor. The feasibility of these remote inspection techniques using ultrasonic waveguide sensor has been evaluated by an experimental verification.

  7. State space modeling of reactor core in a pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ashaari, A.; Ahmad, T.; M, Wan Munirah W. [Department of Mathematical Science, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Shamsuddin, Mustaffa [Institute of Ibnu Sina, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Abdullah, M. Adib [Swinburne University of Technology, Faculty of Engineering, Computing and Science, Jalan Simpang Tiga, 93350 Kuching, Sarawak (Malaysia)

    2014-07-10

    The power control system of a nuclear reactor is the key system that ensures a safe operation for a nuclear power plant. However, a mathematical model of a nuclear power plant is in the form of nonlinear process and time dependent that give very hard to be described. One of the important components of a Pressurized Water Reactor is the Reactor core. The aim of this study is to analyze the performance of power produced from a reactor core using temperature of the moderator as an input. Mathematical representation of the state space model of the reactor core control system is presented and analyzed in this paper. The data and parameters are taken from a real time VVER-type Pressurized Water Reactor and will be verified using Matlab and Simulink. Based on the simulation conducted, the results show that the temperature of the moderator plays an important role in determining the power of reactor core.

  8. State space modeling of reactor core in a pressurized water reactor

    Science.gov (United States)

    Ashaari, A.; Ahmad, T.; Shamsuddin, Mustaffa; M, Wan Munirah W.; Abdullah, M. Adib

    2014-07-01

    The power control system of a nuclear reactor is the key system that ensures a safe operation for a nuclear power plant. However, a mathematical model of a nuclear power plant is in the form of nonlinear process and time dependent that give very hard to be described. One of the important components of a Pressurized Water Reactor is the Reactor core. The aim of this study is to analyze the performance of power produced from a reactor core using temperature of the moderator as an input. Mathematical representation of the state space model of the reactor core control system is presented and analyzed in this paper. The data and parameters are taken from a real time VVER-type Pressurized Water Reactor and will be verified using Matlab and Simulink. Based on the simulation conducted, the results show that the temperature of the moderator plays an important role in determining the power of reactor core.

  9. Precision spectroscopy with reactor anti-neutrinos

    CERN Document Server

    Huber, P; Huber, Patrick; Schwetz, Thomas

    2004-01-01

    In this work we present an accurate parameterization of the anti-neutrino flux produced by the isotopes 235U, 239Pu and 241Pu in nuclear reactors. We determine the coefficients of this parameterization, as well as their covariance matrix, by performing a fit to spectra inferred from experimentally measured beta spectra. Subsequently we show that flux shape uncertainties play only a minor role in the KamLAND experiment, however, we find that future reactor neutrino experiments to measure the mixing angle $\\theta_{13}$ are sensitive to the fine details of the reactor neutrino spectra. Finally, we investigate the possibility to determine the isotopic composition in nuclear reactors through an anti-neutrino measurement. We find that with a 3 month exposure of a one ton detector the isotope fractions and the thermal reactor power can be determined at a few percent accuracy, which may open the possibility of an application for safeguard or non-proliferation objectives.

  10. Scanning tunneling microscope assembly, reactor, and system

    Science.gov (United States)

    Tao, Feng; Salmeron, Miquel; Somorjai, Gabor A

    2014-11-18

    An embodiment of a scanning tunneling microscope (STM) reactor includes a pressure vessel, an STM assembly, and three spring coupling objects. The pressure vessel includes a sealable port, an interior, and an exterior. An embodiment of an STM system includes a vacuum chamber, an STM reactor, and three springs. The three springs couple the STM reactor to the vacuum chamber and are operable to suspend the scanning tunneling microscope reactor within the interior of the vacuum chamber during operation of the STM reactor. An embodiment of an STM assembly includes a coarse displacement arrangement, a piezoelectric fine displacement scanning tube coupled to the coarse displacement arrangement, and a receiver. The piezoelectric fine displacement scanning tube is coupled to the coarse displacement arrangement. The receiver is coupled to the piezoelectric scanning tube and is operable to receive a tip holder, and the tip holder is operable to receive a tip.

  11. Reactor assessments of advanced bumpy torus configurations

    Energy Technology Data Exchange (ETDEWEB)

    Uckan, N.A.; Owen, L.W.; Spong, D.A.; Miller, R.L.; Ard, W.B.; Pipkins, J.F.; Schmitt, R.J.

    1984-02-01

    Recently, several innovative approaches were introduced for enhancing the performance of the basic ELMO Bumpy Torus (EBT) concept and for improving its reactor potential. These include planar racetrack and square geometries, Andreoletti coil systems, and bumpy torus-stellarator hybrids (which include twisted racetrack and helical axis stellarator - snakey torus). Preliminary evaluations of reactor implications of each approach have been carried out based on magnetics (vacuum) calculations, transport and scaling relationships, and stability properties deduced from provisional configurations that implement the approach but are not necessarily optimized. Further optimization is needed in all cases to evaluate the full potential of each approach. Results of these studies indicate favorable reactor projections with a significant reduction in reactor physical size as compared to conventional EBT reactor designs carried out in the past.

  12. Reactivity control assembly for nuclear reactor. [LMFBR

    Science.gov (United States)

    Bollinger, L.R.

    1982-03-17

    This invention, which resulted from a contact with the United States Department of Energy, relates to a control mechanism for a nuclear reactor and, more particularly, to an assembly for selectively shifting different numbers of reactivity modifying rods into and out of the core of a nuclear reactor. It has been proposed heretofore to control the reactivity of a breeder reactor by varying the depth of insertion of control rods (e.g., rods containing a fertile material such as ThO/sub 2/) in the core of the reactor, thereby varying the amount of neutron-thermalizing coolant and the amount of neutron-capturing material in the core. This invention relates to a mechanism which can advantageously be used in this type of reactor control system.

  13. Power Control Method for Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Baang, Dane; Suh, Yongsuk; Park, Cheol [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Considering safety-oriented design concept and other control environment, we developed a simple controller that provides limiting function of power change- rate as well as fine tracking performance. The design result has been well-proven via simulation and actual application to a TRIGA-II type research reactor. The proposed controller is designed to track the PDM(Power Demand) from operator input as long as maintaining the power change rate lower than a certain value for stable reactor operation. A power control method for a TRIGA-II type research reactor has been designed, simulated, and applied to actual reactor. The control performance during commissioning test shows that the proposed controller provides fine control performance for various changes in reference values (PDM), even though there is large measurement noise from neutron detectors. The overshoot at low power level is acceptable in a sense of reactor operation.

  14. Ceramic oxygen transport membrane array reactor and reforming method

    Science.gov (United States)

    Kelly, Sean M.; Christie, Gervase Maxwell; Robinson, Charles; Wilson, Jamie R.; Gonzalez, Javier E.; Doraswami, Uttam R.

    2016-11-08

    The invention relates to a commercially viable modular ceramic oxygen transport membrane reforming reactor configured using repeating assemblies of oxygen transport membrane tubes and catalytic reforming reactors.

  15. Visuomotorisk utveckling mätt med Bendertestet : En jämförelse mellan för tidigt födda och fullgångna barn vid 5 1/2 års ålder.

    OpenAIRE

    Lundequist, Aiko

    2006-01-01

    Sammanfattning Barns utveckling under de sista förskoleåren är nyckeln till en bra skolstart. Visuomotorik är en av de faktorer som krävs för att tillägna sig skolans basfärdigheter. För tidigt födda barn är en grupp som enligt tidigare forskning löper risk för en sämre visuomotorisk utveckling. I den här studien mättes visuomotorik med Bender Gestalt Test med utvärderingssytem utvecklade av främst Elizabeth Koppitz (1963, 1975). I studien jämfördes för tidigt födda barns (n=175) och matchade...

  16. Fast Spectrum Molten Salt Reactor Options

    Energy Technology Data Exchange (ETDEWEB)

    Gehin, Jess C [ORNL; Holcomb, David Eugene [ORNL; Flanagan, George F [ORNL; Patton, Bruce W [ORNL; Howard, Rob L [ORNL; Harrison, Thomas J [ORNL

    2011-07-01

    During 2010, fast-spectrum molten-salt reactors (FS-MSRs) were selected as a transformational reactor concept for light-water reactor (LWR)-derived heavy actinide disposition by the Department of Energy-Nuclear Energy Advanced Reactor Concepts (ARC) program and were the subject of a preliminary scoping investigation. Much of the reactor description information presented in this report derives from the preliminary studies performed for the ARC project. This report, however, has a somewhat broader scope-providing a conceptual overview of the characteristics and design options for FS-MSRs. It does not present in-depth evaluation of any FS-MSR particular characteristic, but instead provides an overview of all of the major reactor system technologies and characteristics, including the technology developments since the end of major molten salt reactor (MSR) development efforts in the 1970s. This report first presents a historical overview of the FS-MSR technology and describes the innovative characteristics of an FS-MSR. Next, it provides an overview of possible reactor configurations. The following design features/options and performance considerations are described including: (1) reactor salt options-both chloride and fluoride salts; (2) the impact of changing the carrier salt and actinide concentration on conversion ratio; (3) the conversion ratio; (4) an overview of the fuel salt chemical processing; (5) potential power cycles and hydrogen production options; and (6) overview of the performance characteristics of FS-MSRs, including general comparative metrics with LWRs. The conceptual-level evaluation includes resource sustainability, proliferation resistance, economics, and safety. The report concludes with a description of the work necessary to begin more detailed evaluation of FS-MSRs as a realistic reactor and fuel cycle option.

  17. Radiation protection at new reactors

    Energy Technology Data Exchange (ETDEWEB)

    Brissaud, A. [EDF INDUSTRY, Basic Design Department, EDF-SEPTEN, VILLEURBANNE Cedex (France)

    2000-05-01

    The theoritical knowledge and the feedback of operating experience concerning radiations in reactors is now considerable. It is available to the designer in the form of predictive softwares and data bases. Thus, it is possible to include the radiation protection component throughout all the design process. In France, the existing reactors have not been designed with quantified radiation protection targets, although considerable efforts have been made to reduce sources of radiation illustrated by the decrease of the average dose rates (typically a factor 5 between the first 900 MWe and the last 1300 MWe units). The EDF ALARA PROJECT has demonstrated that good practises, radiation protection awareness, careful work organization had a strong impact on operation and maintenance work volume. A decrease of the average collective dose by a factor 2 has been achieved without noticeable modifications of the units. In the case of new nuclear facilities projects (reactor, intermediate storage facility,...), or special operations (such as steam generator replacement), quantified radiation protection targets are included in terms of collective and average individual doses within the frame of a general optimization scheme. The target values by themselves are less important than the application of an optimization process throughout the design. This is because the optimization process requires to address all the components of the dose, particularly the work volume for operation and maintenance. A careful study of this parameter contributes to the economy of the project (suppression of unecessary tasks, time-saving ergonomy of work sites). This optimization process is currently applied to the design of the EPR. General radiation protection provisions have been addressed during the basic design phase by applying general rules aiming at the reduction of sources and dose rates. The basic design optimization phase has mainly dealt with the possibility to access the containment at full

  18. The research reactors their contribution to the reactors physics; Les reacteurs de recherche leur apport sur la physique des reacteurs

    Energy Technology Data Exchange (ETDEWEB)

    Barral, J.C. [Electricite de France (EDF), 75 - Paris (France); Zaetta, A. [CEA/Cadarache, Direction des Reacteurs Nucleaires, DRN, 13 - Saint-Paul-lez-Durance (France); Johner, J. [CEA/Cadarache, Dept. de Recherches sur la Fusion Controlee (DRFC), 13 - Saint Paul lez Durance (France); Mathoniere, G. [CEA/Saclay, DEN, 91 - Gif sur Yvette (France)] [and others

    2000-07-01

    The 19 october 2000, the french society of nuclear energy organized a day on the research reactors. This associated report of the technical session, reactors physics, is presented in two parts. The first part deals with the annual meeting and groups general papers on the pressurized water reactors, the fast neutrons reactors and the fusion reactors industry. The second part presents more technical papers about the research programs, critical models, irradiation reactors (OSIRIS and Jules Horowitz) and computing tools. (A.L.B.)

  19. PCCF flow analysis -- DR Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Calkin, J.F.

    1961-04-26

    This report contains an analysis of PCCF tube flow and Panellit pressure relations at DR reactor. Supply curves are presented at front header pressures from 480 to 600 psig using cold water and the standard 0.236 inch orifice with taper down stream and the pigtail valve (plug or ball) open. Demand curves are presented for slug column lengths of 200 inches to 400 inches using 1.44 inch O.D. solid poison pieces (either Al or Pb-Cd) and cold water with a rear header pressure of 50 psig. Figure 1 is a graph of Panellit pressure vs. flow with the above supply and demand curves and clearly shows the effect of front header pressure and charge length on flow.

  20. Coacervates as prebiotic chemical reactors

    Science.gov (United States)

    Kolb, Vera M.; Swanson, Mercedes; Menger, Fredric M.

    2012-10-01

    Coacervates are colloidal systems that are comprised of two immiscible aqueous layers, the colloid-rich layer, so-called coacervate, and the colloid-poor layer, so-called equilibrium liquid. Although immiscible, the two phases are both water-rich. Coacervates are important for prebiotic chemistry, but also have various practical applications, notably as transport vehicles of personal care products and pharmaceuticals. Our objectives are to explore the potential of coacervates as prebiotic chemical reactors. Since the reaction medium in coacervates is water, this creates a challenge, since most organic reactants are not water-soluble. To overcome this challenge we are utilizing recent Green Chemistry examples of the organic reactions in water, such as the Passerini reaction. We have investigated this reaction in two coacervate systems, and report here our preliminary results.

  1. Replacement reactor to revolutionise magnets

    CERN Document Server

    Atkins, G

    2002-01-01

    Electric motors, hearing aids and magnetic resonance imaging are only some of the applications that will benefit from the first advances in magnets in a quarter of a century. Magnets achieve their characteristics when electrons align themselves to produce a unified magnetic field. Neutrons can probe these magnetic structures. The focus is not just on making more powerful magnets, but also identifying the characteristics that make magnets cheaper and easier for industry to manufacture. Staff from the ANSTO's Neutron Scattering Group have already performed a number of studies on the properties of magnets using using HIFAR, but the Replacement Research Reactor that will produce cold neutrons would allow scientists to investigate the atomic properties of materials with large molecules. A suite of equipment will enable studies at different temperatures, pressures and magnetic fields

  2. Dynamic analysis of process reactors

    Energy Technology Data Exchange (ETDEWEB)

    Shadle, L.J.; Lawson, L.O.; Noel, S.D.

    1995-06-01

    The approach and methodology of conducting a dynamic analysis is presented in this poster session in order to describe how this type of analysis can be used to evaluate the operation and control of process reactors. Dynamic analysis of the PyGas{trademark} gasification process is used to illustrate the utility of this approach. PyGas{trademark} is the gasifier being developed for the Gasification Product Improvement Facility (GPIF) by Jacobs-Siffine Engineering and Riley Stoker. In the first step of the analysis, process models are used to calculate the steady-state conditions and associated sensitivities for the process. For the PyGas{trademark} gasifier, the process models are non-linear mechanistic models of the jetting fluidized-bed pyrolyzer and the fixed-bed gasifier. These process sensitivities are key input, in the form of gain parameters or transfer functions, to the dynamic engineering models.

  3. Reactor operation environmental information document

    Energy Technology Data Exchange (ETDEWEB)

    Wike, L.D.; Specht, W.L.; Mackey, H.E.; Paller, M.H.; Wilde, E.W.; Dicks, A.S.

    1989-12-01

    The Savannah River Site (SRS) is a large United States Department of Energy installation on the upper Atlantic Coastal Plain of South Carolina. The SRS contains diverse habitats, flora, and fauna. Habitats include upland terrestrial areas, varied wetlands including Carolina Bays, the Savannah River swamp system, and impoundment related and riparian wetlands, and the aquatic habitats of several stream systems, two large cooling reservoirs, and the Savannah River. These diverse habitats support a large variety of plants and animals including many commercially or recreational valuable species and several rare, threatened or endangered species. This volume describes the major habitats and their biota found on the SRS, and discuss the impacts of continued operation of the K, L, and P production reactors.

  4. (Meeting on fusion reactor materials)

    Energy Technology Data Exchange (ETDEWEB)

    Jones, R.H. (Pacific Northwest Lab., Richland, WA (USA)); Klueh, R.L.; Rowcliffe, A.F.; Wiffen, F.W. (Oak Ridge National Lab., TN (USA)); Loomis, B.A. (Argonne National Lab., IL (USA))

    1990-11-01

    During his visit to the KfK, Karlsruhe, F. W. Wiffen attended the IEA 12th Working Group Meeting on Fusion Reactor Materials. Plans were made for a low-activation materials workshop at Culham, UK, for April 1991, a data base workshop in Europe for June 1991, and a molecular dynamics workshop in the United States in 1991. At the 11th IEA Executive Committee on Fusion Materials, discussions centered on the recent FPAC and Colombo panel review in the United States and EC, respectively. The Committee also reviewed recent progress toward a neutron source in the United States (CWDD) and in Japan (ESNIT). A meeting with D. R. Harries (consultant to J. Darvas) yielded a useful overview of the EC technology program for fusion. Of particular interest to the US program is a strong effort on a conventional ferritic/martensitic steel for fist wall/blanket operation beyond NET/ITER.

  5. From the Switzerland Traditional Barn Reconstruction to See the Old and New Relationships Treatment in the Vernacular Buildings Reconstruction%从瑞士传统谷仓改造看乡土建筑改造中的新旧关系处理

    Institute of Scientific and Technical Information of China (English)

    陈钊

    2014-01-01

    This article bases on the analysis and introduction of three typical examples to the Switzerland barn traditional barn reconstruction, and explores the main mode of dealing with the old andnew relationships in the vernacular buildings reconstruction.%本文通过对瑞士谷仓改造的三个典型实例的分析与说明,探索了乡土建筑改造中,处理新旧关系的主要模式。

  6. EL ESTRÉS AGUDO INTERFIERE CON LA EVOCACIÓN Y PROMUEVE LA EXTINCIÓN DE LA MEMORIA ESPACIAL EN EL LABERINTO DE BARNES

    Directory of Open Access Journals (Sweden)

    JULIETA TRONCOSO

    2010-01-01

    Full Text Available Para evaluar los efectos del estrés agudo sobre la recuperación y la extinción de la memoria espacial, se utilizaron ratas entrenadas en el laberinto circular de Barnes. El entrenamiento consistió de 8 ensayos de adquisición (intervalo entre ensayos, IEE, de 5 min en donde los animales debían aprender a encontrar una caja meta, ubicada en uno de los 18 agu- jeros del laberinto. Todos los animales adquirieron el aprendizaje espacial, ya que invirtieron menos tiempo en encontrar la caja meta y cometieron menos errores a medida que se sucedían los ensayos de entrenamiento. Veinticuatro horas después del entrena- miento se evaluó la retención y extinción del aprendizaje espacial mediante una prueba con caja meta (PCC seguida de siete pruebas sin caja (PSC, con un IEE de 5 min. Una hora y media antes de la sesión de evaluación de la memoria un grupo de animales fue sometido a estrés por restricción de movimientos durante una hora, permitiéndoles un período de recuperación de 30 min y otro grupo permaneció en su caja hogar sin mani- pulación (control. Los resultados indican que el estrés deteriora el proceso de evocación de la memoria espacial, ya que los animales estresados cometieron un mayor número de errores y demoraron más tiempo en encontrar la caja meta durante la PCC, respecto de los controles. Además, el estrés facilita el proceso de extinción, ya que, durante las PSCs los animales estresados no mostraron una persistencia en la exploración del agujero que, en el entrenamiento, conducía a la caja meta.

  7. Flexible Conversion Ratio Fast Reactor Systems Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Neil Todreas; Pavel Hejzlar

    2008-06-30

    Conceptual designs of lead-cooled and liquid salt-cooled fast flexible conversion ratio reactors were developed. Both concepts have cores reated at 2400 MWt placed in a large-pool-type vessel with dual-free level, which also contains four intermediate heat exchanges coupling a primary coolant to a compact and efficient supercritical CO2 Brayton cycle power conversion system. Decay heat is removed passively using an enhanced Reactor Vessel Auxiliary Cooling System and a Passive Secondary Auxiliary Cooling System. The most important findings were that (1) it is feasible to design the lead-cooled and salt-cooled reactor with the flexible conversion ratio (CR) in the range of CR=0 and CR=1 n a manner that achieves inherent reactor shutdown in unprotected accidents, (2) the salt-cooled reactor requires Lithium thermal Expansion Modules to overcme the inherent salt coolant's large positive coolant temperature reactivity coefficient, (3) the preferable salt for fast spectrum high power density cores is NaCl-Kcl-MgCl2 as opposed to fluoride salts due to its better themal-hydraulic and neutronic characteristics, and (4) both reactor, but attain power density 3 times smaller than that of the sodium-cooled reactor.

  8. The Swedish Zero Power Reactor R0

    Energy Technology Data Exchange (ETDEWEB)

    Landergaard, Olof; Cavallin, Kaj; Jonsson, Georg

    1961-05-15

    The reactor R0 is a critical facility built for heavy water and natural uranium or fuel of low enrichment,, The first criticality was achieved September 25, 1959. During a first period of more than two years the R0 will be operated as a bare reactor in order to simplify interpretation of results. The reactor tank is 3. 2 m high and 2. 25 m in diameter. The fuel suspension system is quite flexible in order to facilitate fuel exchange and lattice variations. The temperature of the water can be varied between about 10 and 90 C by means of a heater and a cooler placed in the external circulating system. The instrumentation of the reactor has to meet the safety requirements not only during operation but also during rearrangements of the core in the shut-down state. Therefore, the shut-down state is always defined by a certain low 'safe' moderator level in the reactor tank. A number of safety rods are normally kept above the moderator ready for action. For manual or automatic control of the reactor power a specially designed piston pump is needed, by which the moderator level is varied. The pump speed is controlled from the reactor power error by means of a Ward-Leonard system. Moderator level measurement is made by means of a water gauge with an accuracy of {+-} 0. 1 mm.

  9. Facility for a Low Power Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Chalker, R. G.

    1949-09-14

    Preliminary investigation indicates that a reactor facility with ample research provisions for use by University or other interested groups, featuring safety in design, can be economically constructed in the Los Angeles area. The complete installation, including an underground gas-tight reactor building, with associated storage and experiment assembly building, administration offices, two general laboratory buildings, hot latoratory and lodge, can be constructed for approxinately $1,500,000. This does not include the cost of the reactor itself or of its auxiliary equipment,

  10. Pyrometric fuel particle measurements in pressurised reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hernberg, R.; Joutsenoja, T. [Tampere Univ. of Technology (Finland)

    1996-12-01

    A fiberoptic two-colour pyrometric technique for fuel particle temperature and size measurement is modified and applied to three pressurized reactors of different type in Finland, Germany and France. A modification of the pyrometric method for simultaneous in situ measurement of the temperature and size of individual pulverized coal particles at the pressurized entrained flow reactor in Jyvaeskylae was developed and several series of measurements were made. In Orleans a fiberoptic pyrometric device was installed to a pressurised thermogravimetric reactor and the two-colour temperatures of fuel samples were measured. Some results of these measurements are presented. The project belongs to EU`s Joule 2 extension research programme. (author)

  11. Oxidation performance of graphite material in reactors

    Institute of Scientific and Technical Information of China (English)

    Xiaowei LUO; Xinli YU; Suyuan YU

    2008-01-01

    Graphite is used as a structural material and moderator for high temperature gas-cooled reactors (HTGR). When a reactor is in operation, graphite oxida-tion influences the safety and operation of the reactor because of the impurities in the coolant and/or the acci-dent conditions, such as water ingress and air ingress. In this paper, the graphite oxidation process is introduced, factors influencing graphite oxidation are analyzed and discussed, and some new directions for further study are pointed out.

  12. Sistemas de salvaguardia en reactores EPR

    OpenAIRE

    2015-01-01

    En este documento se describe brevemente el funcionamiento de los diversos sistemas de una planta nuclear operada con un reactor de tipo PWR. Más concretamente, el proyecto se centra en una descripción exhaustiva de los sistemas de salvaguardia y seguridad que regulan el funcionamiento de un reactor de tipo EPR, así como la central nuclear que contiene a dicho reactor. El proceso ha consistido en clasificar y resumir los distintos sistemas que operan en dicha planta, estudiando sus caracterís...

  13. Packed fluidized bed blanket for fusion reactor

    Science.gov (United States)

    Chi, John W. H.

    1984-01-01

    A packed fluidized bed blanket for a fusion reactor providing for efficient radiation absorption for energy recovery, efficient neutron absorption for nuclear transformations, ease of blanket removal, processing and replacement, and on-line fueling/refueling. The blanket of the reactor contains a bed of stationary particles during reactor operation, cooled by a radial flow of coolant. During fueling/refueling, an axial flow is introduced into the bed in stages at various axial locations to fluidize the bed. When desired, the fluidization flow can be used to remove particles from the blanket.

  14. Monitoring and control of anaerobic reactors

    DEFF Research Database (Denmark)

    Pind, Peter Frode; Angelidaki, Irini; Ahring, Birgitte Kiær;

    2003-01-01

    measurements are reviewed in detail. In the sequel, possible manipulated variables, such as the hydraulic retention time, the organic loading rate, the sludge retention time, temperature, pH and alkalinity are evaluated with respect to the two main reactor types: high-rate and low-rate. Finally, the different......The current status in monitoring and control of anaerobic reactors is reviewed. The influence of reactor design and waste composition on the possible monitoring and control schemes is examined. After defining the overall control structure, and possible control objectives, the possible process...

  15. Transients in reactors for power systems compensation

    Science.gov (United States)

    Abdul Hamid, Haziah

    This thesis describes new models and investigations into switching transient phenomena related to the shunt reactors and the Mechanically Switched Capacitor with Damping Network (MSCDN) operations used for reactive power control in the transmission system. Shunt reactors and MSCDN are similar in that they have reactors. A shunt reactor is connected parallel to the compensated lines to absorb the leading current, whereas the MSCDN is a version of a capacitor bank designed as a C-type filter for use in the harmonic-rich environment. In this work, models have been developed and transient overvoltages due to shunt reactor deenergisation were estimated analytically using MathCad, a mathematical program. Computer simulations used the ATP/EMTP program to reproduce both single-phase and three-phase shunt reactor switching at 275 kV operational substations. The effect of the reactor switching on the circuit breaker grading capacitor was also examined by considering various switching conditions.. The main original achievement of this thesis is the clarification of failure mechanisms occurring in the air-core filter reactor due to MSCDN switching operations. The simulation of the MSCDN energisation was conducted using the ATP/EMTP program in the presence of surge arresters. The outcome of this simulation shows that extremely fast transients were established across the air-core filter reactor. This identified transient event has led to the development of a detailed air-core reactor model, which accounts for the inter-turn RLC parameters as well as the stray capacitances-to-ground. These parameters are incorporated into the transient simulation circuit, from which the current and voltage distribution across the winding were derived using electric field and equivalent circuit modelling. Analysis of the results has revealed that there are substantial dielectric stresses imposed on the winding insulation that can be attributed to a combination of three factors. (i) First, the

  16. Assessing Pretreatment Reactor Scaling Through Empirical Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lischeske, James J.; Crawford, Nathan C.; Kuhn, Erik; Nagle, Nicholas J.; Schell, Daniel J.; Tucker, Melvin P.; McMillan, James D.; Wolfrum, Edward J.

    2016-12-01

    Pretreatment is a critical step in the biochemical conversion of lignocellulosic biomass to fuels and chemicals. Due to the complexity of the physicochemical transformations involved, predictively scaling up technology from bench- to pilot-scale is difficult. This study examines how pretreatment effectiveness under nominally similar reaction conditions is influenced by pretreatment reactor design and scale using four different pretreatment reaction systems ranging from a 3 g batch reactor to a 10 dry-ton/d continuous reactor. The reactor systems examined were an Automated Solvent Extractor (ASE), Steam Explosion Reactor (SER), ZipperClave(R) reactor (ZCR), and Large Continuous Horizontal-Screw Reactor (LHR). To our knowledge, this is the first such study performed on pretreatment reactors across a range of reaction conditions (time and temperature) and at different reactor scales. The comparative pretreatment performance results obtained for each reactor system were used to develop response surface models for total xylose yield after pretreatment and total sugar yield after pretreatment followed by enzymatic hydrolysis. Near- and very-near-optimal regions were defined as the set of conditions that the model identified as producing yields within one and two standard deviations of the optimum yield. Optimal conditions identified in the smallest-scale system (the ASE) were within the near-optimal region of the largest scale reactor system evaluated. A reaction severity factor modeling approach was shown to inadequately describe the optimal conditions in the ASE, incorrectly identifying a large set of sub-optimal conditions (as defined by the RSM) as optimal. The maximum total sugar yields for the ASE and LHR were 95%, while 89% was the optimum observed in the ZipperClave. The optimum condition identified using the automated and less costly to operate ASE system was within the very-near-optimal space for the total xylose yield of both the ZCR and the LHR, and was

  17. Passive compact molten salt reactor (PCMSR), modular thermal breeder reactor with totally passive safety system

    Energy Technology Data Exchange (ETDEWEB)

    Harto, Andang Widi [Engineering Physics Department, Faculty of Engineering, Gadjah Mada University (Indonesia)

    2012-06-06

    Design Study Passive Compact Molten Salt Reactor (PCMSR) with totally passive safety system has been performed. The term of Compact in the PCMSR name means that the reactor system is designed to have relatively small volume per unit power output by using modular and integral concept. In term of modular, the reactor system consists of three modules, i.e. reactor module, turbine module and fuel management module. The reactor module is an integral design that consists of reactor, primary and intermediate heat exchangers and passive post shutdown cooling system. The turbine module is an integral design of a multi heating, multi cooling, regenerative gas turbine. The fuel management module consists of all equipments related to fuel preparation, fuel reprocessing and radioactive handling. The preliminary calculations show that the PCMSR has negative temperature and void reactivity coefficient, passive shutdown characteristic related to fuel pump failure and possibility of using natural circulation for post shutdown cooling system.

  18. Advanced research reactor fuel development

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chang Kyu; Pak, H. D.; Kim, K. H. [and others

    2000-05-01

    The fabrication technology of the U{sub 3}Si fuel dispersed in aluminum for the localization of HANARO driver fuel has been launches. The increase of production yield of LEU metal, the establishment of measurement method of homogeneity, and electron beam welding process were performed. Irradiation test under normal operation condition, had been carried out and any clues of the fuel assembly breakdown was not detected. The 2nd test fuel assembly has been irradiated at HANARO reactor since 17th June 1999. The quality assurance system has been re-established and the eddy current test technique has been developed. The irradiation test for U{sub 3}Si{sub 2} dispersed fuels at HANARO reactor has been carried out in order to compare the in-pile performance of between the two types of U{sub 3}Si{sub 2} fuels, prepared by both the atomization and comminution processes. KAERI has also conducted all safety-related works such as the design and the fabrication of irradiation rig, the analysis of irradiation behavior, thermal hydraulic characteristics, stress analysis for irradiation rig, and thermal analysis fuel plate, for the mini-plate prepared by international research cooperation being irradiated safely at HANARO. Pressure drop test, vibration test and endurance test were performed. The characterization on powders of U-(5.4 {approx} 10 wt%) Mo alloy depending on Mo content prepared by rotating disk centrifugal atomization process was carried out in order to investigate the phase stability of the atomized U-Mo alloy system. The {gamma}-U phase stability and the thermal compatibility of atomized U-16at.%Mo and U-14at.%Mo-2at.%X(: Ru, Os) dispersion fuel meats at an elevated temperature have been investigated. The volume increases of U-Mo compatibility specimens were almost the same as or smaller than those of U{sub 3}Si{sub 2}. However the atomized alloy fuel exhibited a better irradiation performance than the comminuted alloy. The RERTR-3 irradiation test of nano

  19. Hydrodynamics of multi-phase packed bed micro-reactors

    NARCIS (Netherlands)

    Márquez Luzardo, N.M.

    2010-01-01

    Why to use packed bed micro-reactors for catalyst testing? Miniaturized packed bed reactors have a large surface-to-volume ratio at the reactor and particle level that favors the heat- and mass-transfer processes at all scales (intra-particle, inter-phase and inter-particle or reactor level). If the

  20. Progress of China Experimental Fast Reactor in 2011

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    1 Background Fast reactor is the reactor which realized the chain fission with fast neutron.As an optional type of generation Ⅳ reactor,fast reactor has three characters:1) It can change 238U to 239Pu and raise the uranium resource utilization

  1. Uncertainties in the Anti-neutrino Production at Nuclear Reactors

    OpenAIRE

    Djurcic, Z.(Argonne National Laboratory, Argonne, Illinois, 60439, U.S.A.); Detwiler, J. A.; Piepke, A.; Foster Jr., V. R.; Miller, L.; Gratta, G.

    2008-01-01

    Anti-neutrino emission rates from nuclear reactors are determined from thermal power measurements and fission rate calculations. The uncertainties in these quantities for commercial power plants and their impact on the calculated interaction rates in electron anti-neutrino detectors is examined. We discuss reactor-to-reactor correlations between the leading uncertainties and their relevance to reactor anti-neutrino experiments.

  2. Ex-vessel Steam Explosion Analysis for Pressurized Water Reactor and Boiling Water Reactor

    OpenAIRE

    Matjaž Leskovar; Mitja Uršič

    2016-01-01

    A steam explosion may occur during a severe accident, when the molten core comes into contact with water. The pressurized water reactor and boiling water reactor ex-vessel steam explosion study, which was carried out with the multicomponent three-dimensional Eulerian fuel–coolant interaction code under the conditions of the Organisation for Economic Co-operation and Development (OECD) Steam Explosion Resolution for Nuclear Applications project reactor exercise, is presented and discussed. In ...

  3. Optimization of a sequence of reactors

    DEFF Research Database (Denmark)

    Vidal, Rene Victor Valqui

    1991-01-01

    Concerns the optimal production of sulphuric acid in a sequence of reactors. Using a suitable approximation to the objective function, this problem can easily be solved using the maximum principle. A numerical example documents the applicability of the suggested approach...

  4. The Bifurcation Behavior of CO Coupling Reactor

    Institute of Scientific and Technical Information of China (English)

    徐艳; 马新宾; 许根慧

    2005-01-01

    The bifurcation behavior of the CO coupling reactor was examined based on the one-dimensional pseudohomogeneous axial dispersion dynamic model. The method of finite difference was used for solving the boundary value problem; the continuation technique and the direct method were applied to determine the bifurcation diagram.The effects of dimensionless adiabatic temperature rise, Damkoehler number, activation energy, heat transfer coefficient and feed ratio on the bifurcation behavior were investigated. It was shown that there existed static bifurcation and the oscillations did not occur in the reactor. The result also revealed that the reactor exhibited at most 1-3-1 multiplilicity patterns within the range of practical possible parameters and the measures, such as weakening the axial dispersion of reactor, enhancing heat transfer, decreasing the concentration of ethyl nitrite, were efficient for avoiding the possible risk of multiple steady states.

  5. Heat pipe reactors for space power applications

    Science.gov (United States)

    Koenig, D. R.; Ranken, W. A.; Salmi, E. W.

    1977-01-01

    A family of heat pipe reactors design concepts has been developed to provide heat to a variety of electrical conversion systems. Three power plants are described that span the power range 1-500 kWe and operate in the temperature range 1200-1700 K. The reactors are fast, compact, heat-pipe cooled, high-temperature nuclear reactors fueled with fully enriched refractory fuels, UC-ZrC or UO2. Each fuel element is cooled by an axially located molybdenum heat pipe containing either sodium or lithium vapor. Virtues of the reactor designs are the avoidance of single-point failure mechanisms, the relatively high operating temperature, and the expected long lifetimes of the fuel element components.

  6. Reactor Antineutrinos: From Confusion to Clarity

    Science.gov (United States)

    Dwyer, Dan

    2016-09-01

    Antineutrinos emitted by nuclear reactors have been a powerful tool for particle physics, demonstrating the existence of these weakly-interacting particles as well as their flavor oscillation. Despite these successes, our understanding of the total flux and energy spectra of reactor antineutrinos has been fraught with problems. I will give a brief overview of the unexpected developments in this field, and discuss upcoming measurements of antineutrinos, beta decays, and nuclear fission which are relevant to these questions. These measurements are expected to clarify many currently murky issues, including the hypothetical oscillation of reactor antineutrinos to sterile states. The results should also provide a unique perspective into the nuclear physics of fission reactors. DOE OHEP DE-AC02-05CH11231.

  7. Chemical reactor modeling multiphase reactive flows

    CERN Document Server

    Jakobsen, Hugo A

    2014-01-01

    Chemical Reactor Modeling closes the gap between Chemical Reaction Engineering and Fluid Mechanics.  The second edition consists of two volumes: Volume 1: Fundamentals. Volume 2: Chemical Engineering Applications In volume 1 most of the fundamental theory is presented. A few numerical model simulation application examples are given to elucidate the link between theory and applications. In volume 2 the chemical reactor equipment to be modeled are described. Several engineering models are introduced and discussed. A survey of the frequently used numerical methods, algorithms and schemes is provided. A few practical engineering applications of the modeling tools are presented and discussed. The working principles of several experimental techniques employed in order to get data for model validation are outlined. The monograph is based on lectures regularly taught in the fourth and fifth years graduate courses in transport phenomena and chemical reactor modeling, and in a post graduate course in modern reactor m...

  8. µ-reactors for Heterogeneous Catalysis

    DEFF Research Database (Denmark)

    Jensen, Robert

    catalyst surface area by reacting off an adsorbed layer of oxygen with CO. This procedure can be performed at temperatures low enough that sintering of Pt nanoparticles is not an issue. Some results from the reactors are presented. In particular an unexpected oscillation phenomenon of CO-oxidation on Pt...... nanoparticles are presented in detail. The sensitivity of the reactors are currently being investigated with CO oxidation on Pt thin films as a test reaction, and the results so far are presented. We have at this point shown that we are able to reach full conversion with a catalyst area of 38 µm2 with a turn......This thesis is the summary of my work on the µ-reactor platform. The concept of µ-reactors is presented and some of the experimental challenges are outlined. The various experimental issues regarding the platform are discussed and the actual implementation of three generations of the setup...

  9. Corrosion Minimization for Research Reactor Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Eric Shaber; Gerard Hofman

    2005-06-01

    Existing university research reactors are being converted to use low-enriched uranium fue to eliminate the use of highly-enriched uranium. These conversions require increases in fuel loading that will result in the use of elements with more fuel plates, resulting in a net decrease in the water annulus between fuel plates. The proposed decrease in the water annulus raises questions about the requirements and stability of the surface hydroxide on the aluminum fuel cladding and the potential for runaway corrosion resulting in fuel over-temperature incidents. The Nuclear Regulatory Commission (NRC), as regulator for these university reactors, must ensure that proposed fuel modifications will not result in any increased risk or hazard to the reactor operators or the public. This document reviews the characteristics and behavior of aluminum hydroxides, analyzes the drivers for fuel plate corrosion, reviews relevant historical incidents, and provides recommendations on fuel design, surface treatment, and reactor operational practices to avoid corrosion issues.

  10. Interactions of Pellet with Reactor Relevant Plasma

    Institute of Scientific and Technical Information of China (English)

    PENGLilin; DENGBaiquan; YANJiancheng

    2003-01-01

    Extended algorithm has been developed for ablation rate calculations of Li, Be, B impurity pellets and five combinations of solid isotopic hydrogenic H2, HD, D2, DT, T2 pellets. Numerical calculations have been performed for reactor relevant plasma.

  11. Autonomous Control of Space Nuclear Reactors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Nuclear reactors to support future lunar and Mars robotic and manned missions impose new and innovative technological requirements for their control and protection...

  12. Advanced Test Reactor National Scientific User Facility

    Energy Technology Data Exchange (ETDEWEB)

    Frances M. Marshall; Jeff Benson; Mary Catherine Thelen

    2011-08-01

    The Advanced Test Reactor (ATR), at the Idaho National Laboratory (INL), is a large test reactor for providing the capability for studying the effects of intense neutron and gamma radiation on reactor materials and fuels. The ATR is a pressurized, light-water, high flux test reactor with a maximum operating power of 250 MWth. The INL also has several hot cells and other laboratories in which irradiated material can be examined to study material irradiation effects. In 2007 the US Department of Energy (DOE) designated the ATR as a National Scientific User Facility (NSUF) to facilitate greater access to the ATR and the associated INL laboratories for material testing research by a broader user community. This paper highlights the ATR NSUF research program and the associated educational initiatives.

  13. EMERGING TECHNOLOGY BULLETIN: SPOUTED BED REACTOR

    Science.gov (United States)

    The Spouted Bed Reactor (SBR) technology utilizes the unique attributes of the "spouting " fluidization regime, which can provide heat transfer rates comparable to traditional fluid beds, while providing robust circulation of highly heterogeneous solids, concurrent with very agg...

  14. Molten salt reactors - safety options galore

    Energy Technology Data Exchange (ETDEWEB)

    Gat, U. [Oak Ridge National Lab., TN (United States); Dodds, H.L. [Univ. of Tennessee, Knoxville, TN (United States)

    1997-03-01

    Safety features and attributes of molten salt reactors (MSR) are described. The unique features of fluid fuel reactors of on-line continuous processing and the ability for so-called external cooling result in simple and safe designs with low excess reactivity, low fission product inventory, and small source term. These, in turn, make a criticality accident unlikely and reduce the severity of a loss of coolant to where they are no longer severe accidents. A melt down is not an accident for a reactor that uses molten fuel. The molten salts are stable, non-reactive and efficient heat transfer media that operate at high temperatures at low pressures and are highly compatible with selected structural materials. All these features reduce the accident plethora. Freeze valves can be used for added safety. An ultimate safe reactor (U.S.R) is described with safety features that are passive, inherent and non-tamperable (PINT).

  15. Steady State Analysis of Small Molten Salt Reactor : Effect of Fuel Salt Flow on Reactor Characteristics

    OpenAIRE

    Yamamoto, Takahisa; MITACHI, Koshi; Suzuki, Takashi

    2005-01-01

    The Molten Salt Reactor (MSR) is a thermal neutron reactor with graphite moderation and operates on the thorium-uranium fuel cycle. The feature of the MSR is that fuel salt flows inside the reactor during the nuclear fission reaction. In the previous study, the authors developed numerical model with which to simulate the effects of fuel salt flow on the reactor characteristics. In this study, we apply the model to the steady-state analysis of a small MSR system and estimate the effects of fue...

  16. Development of technology for next generation reactor - Development of next generation reactor in Korea -

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Kyun; Chang, Moon Heuy; Hwang, Yung Dong [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)] [and others

    1993-09-01

    The project, development of next generation reactor, aims overall related technology development and obtainment of related license in 2001. The development direction is to determine the reactor type and to build up the design concept in 1994. For development trend analysis of foreign next generation reactor, level-1 PSA, fuel cycle analysis and computer code development are performed on System 80+ and AP 600. Especially for design characteristics analysis and volume upgrade of AP 600, nuclear fuel and reactor core design analysis, coolant circuit design analysis, mechanical structure design analysis and safety analysis etc. are performed. (Author).

  17. A fast and flexible reactor physics model for simulating neutron spectra and depletion in fast reactors

    Science.gov (United States)

    Recktenwald, Geoff; Deinert, Mark

    2010-03-01

    Determining the time dependent concentration of isotopes within a nuclear reactor core is central to the analysis of nuclear fuel cycles. We present a fast, flexible tool for determining the time dependent neutron spectrum within fast reactors. The code (VBUDS: visualization, burnup, depletion and spectra) uses a two region, multigroup collision probability model to simulate the energy dependent neutron flux and tracks the buildup and burnout of 24 actinides, as well as fission products. While originally developed for LWR simulations, the model is shown to produce fast reactor spectra that show high degree of fidelity to available fast reactor benchmarks.

  18. Corner Office: Gale's Sommers & Barnes

    Science.gov (United States)

    Fialkoff, Francine

    2008-01-01

    This article presents an interview with Patrick Sommers, president of reference/information publisher "Gale" (part of Cengage Learning). Sommers took the helm in October 2007, after running system vendor Sirsi beginning in 2001 and engineering both the 2005 merger with Dynix and the 2007 sale of the newly created SirsiDynix to Vista Equity…

  19. Barns tankar om ekologiska processer

    DEFF Research Database (Denmark)

    Helldén, Gustav

    Bogen indledes med en oversigt over forskning om læring i naturvidenskab, herunder gennemgås blandt andet Piagets teorier. Herefter følger Helldéns undersøgelser af elevforestillinger om økologiske processer. Helldén har interviewet eleverne om livsbetingelser og vækst, nedbrydning i naturen og om...

  20. Psykose i barne- og ungdomsalderen

    DEFF Research Database (Denmark)

    Pagsberg, Anne Katrine; Madsen, Gitte; Bilenberg, Niels

    2008-01-01

    Psychosis in childhood and adolescence is rare. Psychotic manifestations in childhood are associated with diagnostic diversities. The diagnostic group pervasive developmental disorder, not otherwise specified (PDD-NOS) are often used in childhood and may be a precursor of schizophrenia or affecti...... the genesis and aetiology of psychoses. Udgivelsesdato: 2008-Nov-10...