WorldWideScience

Sample records for fischer memorial great

  1. 33 CFR 100.124 - Maggie Fischer Memorial Great South Bay Cross Bay Swim, Great South Bay, New York.

    Science.gov (United States)

    2010-07-01

    ... South Bay Cross Bay Swim, Great South Bay, New York. 100.124 Section 100.124 Navigation and Navigable... NAVIGABLE WATERS § 100.124 Maggie Fischer Memorial Great South Bay Cross Bay Swim, Great South Bay, New York... swimmer or safety craft on the swim event race course bounded by the following points: Starting Point...

  2. 75 FR 29891 - Special Local Regulation; Maggie Fischer Memorial Great South Bay Cross Bay Swim, Great South Bay...

    Science.gov (United States)

    2010-05-28

    ... Swim, Great South Bay, NY, in the Federal Register (74 FR 32428). We did not receive any comments or... published at 74 FR 32428 on July 8, 2009, is adopted as a final rule with the following changes: PART 100... South Bay Cross Bay Swim, Great South Bay, NY AGENCY: Coast Guard, DHS. ACTION: Final rule. SUMMARY:...

  3. The Great War and German Memory

    DEFF Research Database (Denmark)

    Leese, Peter

    2012-01-01

    Review essay on Jason Crouthamel, The Great War and German Memory. Society, Politics and Psychological Trauma, 1914-18 (2009) and Anton Kaes, Shell Shock Cinema: Weimar Culture and the Wounds of War (2009)......Review essay on Jason Crouthamel, The Great War and German Memory. Society, Politics and Psychological Trauma, 1914-18 (2009) and Anton Kaes, Shell Shock Cinema: Weimar Culture and the Wounds of War (2009)...

  4. Psychomotor and spatial memory performance in aging male Fischer 344 rats.

    Science.gov (United States)

    Shukitt-Hale, B; Mouzakis, G; Joseph, J A

    1998-09-01

    Psychomotor and spatial memory performance were examined in male Fischer 344 rats that were 6, 12, 15, 18, and 22 months of age, to assess these parameters as a function of age and to determine at what age these behaviors begin to deteriorate. Complex motor behaviors, as measured by rod walk, wire suspension, plank walk, inclined screen, and accelerating rotarod performance, declined steadily with age, with most measures being adversely affected as early as 12 to 15 months of age. Spatial learning and memory performance, as measured by the working memory version of the Morris water maze (MWM), showed decrements at 18 and 22 months of age (higher latencies on the working memory trial), with some change noticeable as early as 12-15 months of age (no improvement on the second trial following a 10-min retention interval); these differences were not due to swim speed. Therefore, complex motor and spatial memory behaviors show noticeable declines early in the lifespan of the male Fisher 344 rat. This cross-sectional age analysis study using the latest behavioral techniques determines the minimal age at which psychomotor and spatial learning and memory behaviors deteriorate; this information is important when planning for longitudinal studies where interventions are tested for their efficacy in preventing or restoring age-related behavioral deficits.

  5. Age-Related Deficits in Spatial Memory and Hippocampal Spines in Virgin, Female Fischer 344 Rats

    Directory of Open Access Journals (Sweden)

    Victoria N. Luine

    2011-01-01

    Full Text Available Effects of aging on memory and brain morphology were examined in aged, 21-month-old, and young, 4-month-old, Fischer 344 female rats. Spatial memory was assessed using the object placement task, and dendritic spine density was determined on pyramidal neurons in the hippocampus following Golgi impregnation. Consistent with previous studies, aged females showed poorer object placement performance than young subjects. Young subjects significantly discriminated the location of objects with a 1.5-hour intertrial delay while aged subjects did not. Spine density of basal dendrites on CA1 pyramidal cells was 16% lower in the aged subjects as compared to the young subjects. No differences in spine density were found between young and aged subjects in basal dendrites of CA1 or in either dendritic field of CA3 pyramidal neurons. Thus, decreased hippocampal CA1 dendritic spine density in aged rats may contribute to poorer spatial memory as compared to young rats. The possibility that the neuroplastic changes observed in this study may pertain only to female subjects having had a specific set of life experiences is discussed. Different factors, such as reproductive status, diet, and handling may contribute to neuroplasticity of the brain during aging; however, this view requires further examination.

  6. Spatial reference memory in normal aging Fischer 344 × Brown Norway F1 hybrid rats.

    Science.gov (United States)

    McQuail, Joseph A; Nicolle, Michelle M

    2015-01-01

    Fischer 344 × Brown Norway F1 (F344 × BN-F1) hybrid rats express greater longevity with improved health relative to aging rodents of other strains; however, few behavioral reports have thoroughly evaluated cognition across the F344 × BN-F1 lifespan. Consequently, this study evaluated spatial reference memory in F344 × BN-F1 rats at 6, 18, 24, or 28 months of age in the Morris water maze. Reference memory decrements were observed between 6 and 18 months and 18 and 24 months. At 28 months, spatial learning was not worse than 24 months, but swim speed was significantly slower. Reliable individual differences revealed that ∼50% of 24- to 28-month-old rats performed similarly to 6 months, whereas others were spatial learning impaired. Aged rats were impaired at learning within daily training sessions but not impaired at retaining information between days of training. Aged rats were also slower to learn to escape onto the platform, regardless of strategy. In summary, these data clarify the trajectory of cognitive decline in aging F344 × BN-F1 rats and elucidate relevant behavioral parameters.

  7. The Great War, ethics of Vidovdan, memory

    Directory of Open Access Journals (Sweden)

    Šijaković Bogoljub

    2015-01-01

    Full Text Available After a characterization of contemporaneity (dominance of the financial sector and high technology, politicization of economy, ideological use of culture and thought control and a brief analysis of expansionism (political, economic, cultural on the eve of the Great War, the author gives a more detailed description of the spiritual situation in the wake of the Great War: in philosophy, literature, and art, as well as the national political programmatic texts and war propaganda publications of German intellectuals of the time. The continuity of the Austro-Hungarian colonial policy towards the Balkans and Serbia culminated in instigation of a preventive war against Serbia by the elites in Berlin and Vienna, which is important for the question of responsibility for the war, with concrete war aims which reflected in the causes of the war. These war elites wanted to declare the assassination in Sarajevo as the cause of war, which in fact was a political assassination and tyrannicide. The liberation movement of democratic youth Mlada Bosna (Young Bosnia needs to be viewed both in the European context and inspired by the Serbian tradition of Kosovo cult and the ethics of Vidovdan (St Vitus Day speaking about the sacrifice as sublimation of history and about honorable suffering as element of identity. Historical memory suggests that historical responsibility is transgenerational. The epic proportions of Serbian suffering in the Great War have additionally incited the idea of the Temple of St Vitus Day (Vidovdanski Hram conceived by Ivan Meštrović. The bases of this idea were shaken by Miloš Crnjanski in his Lyrics of Ithaca where he succeeded to bring back to Vidovdan (St Vitus Day its inexhaustible national power of validity. Because of enormous Serbian military and civilian casualties in recent history, the establishing of a Victims of War Memorial today would have identity, existential, ethical and ontological significance for the Serbian people

  8. 1990 Fischer Standard study

    Energy Technology Data Exchange (ETDEWEB)

    Roubik, G.J.

    1990-09-12

    The purpose of this work is to develop a set of Titanium areal density standards for calibration and maintenance of the Fischer`s X-ray Fluorescence measurement system characterization curve program. The electron microprobe was calibrated for Titanium films on ceramic substrates using an existing set of laboratory standards (Quantity: 6 Range: 0.310 to 1.605). Fourteen source assemblies were measured and assigned values. These values are based on a mean calculation, of five separate readings, from best curve fit equations developed form the plot of the laboratory standards areal density (Source Measure) versus electron microprobe measurement (reading). The best fit equations were determined using the SAS General Linear Modeling (GLM) procedure. Four separate best fit equations were evaluated (Linear, Quadratic, Cubic and Exponential). Areal density values for the Fischer Standards appear here ordered by best fit equation based on maximum R{sup 2}.

  9. Landscapes of Memory and Forgetting: Memorialisation, Emotion and Tourism along Australia’s Great Ocean Road

    Directory of Open Access Journals (Sweden)

    Rosemary Kerr

    2013-12-01

    Full Text Available This article explores the history of the Great Ocean Road, described in its recent National Heritage listing as “Australia’s most famous coastal drive”. The road is unique in Australia as it was purposely constructed as a scenic tourist route and as a memorial to World War I servicemen. Over time the road’s memorial function was largely forgotten in public memory, overtaken by its fame as a tourist route. The history of the road’s setting, construction, promotion and interpretation reveals that it is a route which reflects changing, and sometimes conflicting, cultural preoccupations. Despite attempts to link its sublime setting and challenges of building the road with the heroic struggles of the servicemen in war; in spite of physical commemorative markers along the road; and in spite of the power and endurance of the “Anzac legend” in Australian culture, the connection did not resonate as intended. The road’s construction and subsequent interpretation illustrate the difficulty of inscribing “memory” onto a landscape with no prior connection to the events being memorialised. Its history reveals insights into the road’s cultural construction; tangible and intangible expressions of remembering and forgetting along the road; and the relationship between the road, landscape, memory and emotion.

  10. “Remembering with advantages”: The memory of the Great War in Australia

    Directory of Open Access Journals (Sweden)

    Carolyn Holbrook

    2015-02-01

    Full Text Available Australian memory of the Great War has always been expressed most enthusiastically in the rituals of Anzac Day: an occasion that recognises the anniversary of the Australians’ first battle of the war in Turkey on 25 April 1915. In the decades after 1914–1918, the devastating effects of the war were assuaged in part by the pride that Australians felt in the fighting reputation of their soldiers. By the 1960s the rituals of Anzac were in noticeable decline. Young Australians were hostile to the values of the Great War generation and believed that the commemorative practices of Anzac Day glorified war. Despite the widespread belief that Anzac Day would die with the last of the old veterans, it has staged a remarkable resurgence. This can be explained by the remaking of the Anzac legend, from a myth anchored in British race patriotism and martial nationalism to one that speaks in the modern idiom of trauma, suffering and empathy. What remains of the original Anzac legend is the belief commonly held by contemporary Australians that their national consciousness was born at Gallipoli on 25 April 1915.

  11. The memory of two great mental calculators: Charcot and Binet's neglected 1893 experiments.

    Science.gov (United States)

    Nicolas, Serge; Gounden, Yannick; Levine, Zachary

    2011-01-01

    French neurologist Jean Martin Charcot (1825-1893) and French psychologist Alfred Binet (1857-1911) are almost unknown as investigators who conducted original and fascinating studies in the area of memory. In a series of 1893 experiments, they compared the performance of two expert mental calculators, Jacques Inaudi and Périclès Diamandi, in tasks that consisted of recalling digits. Inspired by Ribot's psychological work (1881), they believed in the existence of not one type of memory but several partial, special, and local memories, each devoted to a particular domain. In all arithmetical prodigies, memory for digits is abnormally developed compared with other memories. Inaudi was considered to be an auditory memory-based mental calculator; when memorizing digits, he did not rely onthe appearance of the items or create visual imagery of any kind. Rather, he remembered digits principally by their sounds. Inaudi's methods of calculation and memorization were original and different from those used by Diamandi, who was a typical visual memory-based mental calculator. The experiments presented in the 1893 article were among the first scientific demonstrations of the importance to psychology of studying different types of memory. The present work gives a translation of this pioneering experimental article on expert calculators by Charcot and Binet, instructive for the comprehension of normal memory.

  12. Landscapes of Memory and Forgetting: Memorialisation, Emotion and Tourism along Australia’s Great Ocean Road

    National Research Council Canada - National Science Library

    Rosemary Kerr

    2013-01-01

    ... as “Australia’s most famous coastal drive”. The road is unique in Australia as it was purposely constructed as a scenic tourist route and as a memorial to World War I servicemen. Over time...

  13. Keeping track of time: evidence for episodic-like memory in great apes.

    Science.gov (United States)

    Martin-Ordas, Gema; Haun, Daniel; Colmenares, Fernando; Call, Josep

    2010-03-01

    Episodic memory, as defined by Tulving, can be described in terms of behavioural elements (what, where and when information) but it is also accompanied by an awareness of one's past (chronesthesia) and a subjective conscious experience (autonoetic awareness). Recent experiments have shown that corvids and rodents recall the where, what and when of an event. This capability has been called episodic-like memory because it only fulfils the behavioural criteria for episodic memory. We tested seven chimpanzees, three orangutans and two bonobos of various ages by adapting two paradigms, originally developed by Clayton and colleagues to test scrub jays. In Experiment 1, subjects were fed preferred but perishable food (frozen juice) and less preferred but non-perishable food (grape). After the food items were hidden, subjects could choose one of them either after 5 min or 1 h. The frozen juice was still available after 5 min but melted after 1 h and became unobtainable. Apes chose the frozen juice significantly more after 5 min and the grape after 1 h. In Experiment 2, subjects faced two baiting events happening at different times, yet they formed an integrated memory for the location and time of the baiting event for particular food items. We also included a memory task that required no temporal encoding. Our results showed that apes remember in an integrated fashion what, where and when (i.e., how long ago) an event happened; that is, apes distinguished between different events in which the same food items were hidden in different places at different times. The temporal control of their choices was not dependent on the familiarity of the platforms where the food was hidden. Chimpanzees' and bonobos' performance in the temporal encoding task was age-dependent, following an inverted U-shaped distribution. The age had no effect on the performance of the subjects in the task that required no temporal encoding.

  14. Working Memory, Reasoning, and Task Switching Training: Transfer Effects, Limitations, and Great Expectations?

    Directory of Open Access Journals (Sweden)

    Pauline L Baniqued

    Full Text Available Although some studies have shown that cognitive training can produce improvements to untrained cognitive domains (far transfer, many others fail to show these effects, especially when it comes to improving fluid intelligence. The current study was designed to overcome several limitations of previous training studies by incorporating training expectancy assessments, an active control group, and "Mind Frontiers," a video game-based mobile program comprised of six adaptive, cognitively demanding training tasks that have been found to lead to increased scores in fluid intelligence (Gf tests. We hypothesize that such integrated training may lead to broad improvements in cognitive abilities by targeting aspects of working memory, executive function, reasoning, and problem solving. Ninety participants completed 20 hour-and-a-half long training sessions over four to five weeks, 45 of whom played Mind Frontiers and 45 of whom completed visual search and change detection tasks (active control. After training, the Mind Frontiers group improved in working memory n-back tests, a composite measure of perceptual speed, and a composite measure of reaction time in reasoning tests. No training-related improvements were found in reasoning accuracy or other working memory tests, nor in composite measures of episodic memory, selective attention, divided attention, and multi-tasking. Perceived self-improvement in the tested abilities did not differ between groups. A general expectancy difference in problem-solving was observed between groups, but this perceived benefit did not correlate with training-related improvement. In summary, although these findings provide modest evidence regarding the efficacy of an integrated cognitive training program, more research is needed to determine the utility of Mind Frontiers as a cognitive training tool.

  15. Working Memory, Reasoning, and Task Switching Training: Transfer Effects, Limitations, and Great Expectations?

    Science.gov (United States)

    Baniqued, Pauline L; Allen, Courtney M; Kranz, Michael B; Johnson, Kathryn; Sipolins, Aldis; Dickens, Charles; Ward, Nathan; Geyer, Alexandra; Kramer, Arthur F

    2015-01-01

    Although some studies have shown that cognitive training can produce improvements to untrained cognitive domains (far transfer), many others fail to show these effects, especially when it comes to improving fluid intelligence. The current study was designed to overcome several limitations of previous training studies by incorporating training expectancy assessments, an active control group, and "Mind Frontiers," a video game-based mobile program comprised of six adaptive, cognitively demanding training tasks that have been found to lead to increased scores in fluid intelligence (Gf) tests. We hypothesize that such integrated training may lead to broad improvements in cognitive abilities by targeting aspects of working memory, executive function, reasoning, and problem solving. Ninety participants completed 20 hour-and-a-half long training sessions over four to five weeks, 45 of whom played Mind Frontiers and 45 of whom completed visual search and change detection tasks (active control). After training, the Mind Frontiers group improved in working memory n-back tests, a composite measure of perceptual speed, and a composite measure of reaction time in reasoning tests. No training-related improvements were found in reasoning accuracy or other working memory tests, nor in composite measures of episodic memory, selective attention, divided attention, and multi-tasking. Perceived self-improvement in the tested abilities did not differ between groups. A general expectancy difference in problem-solving was observed between groups, but this perceived benefit did not correlate with training-related improvement. In summary, although these findings provide modest evidence regarding the efficacy of an integrated cognitive training program, more research is needed to determine the utility of Mind Frontiers as a cognitive training tool.

  16. Cognitive Ageing in Great Britain in the New Century: Cohort Differences in Episodic Memory.

    Directory of Open Access Journals (Sweden)

    Gindo Tampubolon

    Full Text Available Dementias in high income countries are set to be the third major burden of disease even as older people are increasingly required to think for themselves how to provide for their lives in retirement. Meanwhile the period of older age continues to extend with increase in life expectancy. This challenge demands an understanding of how cognition changes over an extended period in later life. But studying cognitive ageing in the population faces a difficulty from the fact that older respondents are liable to leave (attrite before study completion. This study tested three hypotheses: trajectories of cognitive ageing in Britain show an improvement beyond the age of 50; and they are lifted by secular improvement in cognition across cohorts; lastly they are susceptible to distortion due to attrition.Using the English Longitudinal Study of Ageing, this paper studied trajectories of episodic memory of Britons aged 50-89 from 2002 to 2013 (N = 5931. Using joint models the analysis found that levels of episodic memory follow a curvilinear shape, not a steady decline, in later life. The findings also revealed secular improvement in cognitive ageing such that as a cohort is being replaced episodic memory levels in the population improve. The analysis lastly demonstrated that failure to simultaneously model attrition can produce distorted pictures of cognitive ageing.Old age in this century is not necessarily a period dominated by cognitive decline. In identifying behavioural factors associated with better cognitive ageing, such as social connections of traditional and online kinds, the paper raises possibilities of mustering an adequate response to the cognition challenge.

  17. Commemorations of Imperial Sacrifice at Home and Abroad: British Memorials of the Great War

    Science.gov (United States)

    Johnson, David A.; Gilbertson, Nicole F.

    2010-01-01

    Scholars have long recognized that the Great War produced a remarkable amount of artistic and cultural expression ranging from poetry to painting to novels to architecture. This cultural production, both during and after the war, reflected a deep need to define and understand the tremendous destruction caused by a war that demanded a level of…

  18. Commemorations of Imperial Sacrifice at Home and Abroad: British Memorials of the Great War

    Science.gov (United States)

    Johnson, David A.; Gilbertson, Nicole F.

    2010-01-01

    Scholars have long recognized that the Great War produced a remarkable amount of artistic and cultural expression ranging from poetry to painting to novels to architecture. This cultural production, both during and after the war, reflected a deep need to define and understand the tremendous destruction caused by a war that demanded a level of…

  19. Memory

    Science.gov (United States)

    ... it has to decide what is worth remembering. Memory is the process of storing and then remembering this information. There are different types of memory. Short-term memory stores information for a few ...

  20. Tailored fischer-tropsch synthesis product distribution

    Science.gov (United States)

    Wang, Yong [Richland, WA; Cao, Chunshe [Kennewick, WA; Li, Xiaohong Shari [Richland, WA; Elliott, Douglas C [Richland, WA

    2012-06-19

    Novel methods of Fischer-Tropsch synthesis are described. It has been discovered that conducting the Fischer-Tropsch synthesis over a catalyst with a catalytically active surface layer of 35 microns or less results in a liquid hydrocarbon product with a high ratio of C.sub.5-C.sub.20:C.sub.20+. Descriptions of novel Fischer-Tropsch catalysts and reactors are also provided. Novel hydrocarbon compositions with a high ratio of C.sub.5-C.sub.20:C.sub.20+ are also described.

  1. Novel Fischer-Tropsch catalysts. [DOE patent

    Science.gov (United States)

    Vollhardt, K.P.C.; Perkins, P.

    Novel compounds are described which are used as improved Fischer-Tropsch catalysts particularly for the conversion of CO + H/sub 2/ to gaseous and liquid hydrocarbons at milder conditions than with prior catalysts.

  2. Perspectiva sobre una Personalidad Senera: Carmen Fischer Ramirez (Perspective on a Singular Personality: Carmen Fischer Ramirez).

    Science.gov (United States)

    Quezeda, Dina Alarcon

    1992-01-01

    Traces the career of Carmen Fischer Ramirez, focusing on her work in improving early childhood education in Chile. Reviews her university career, work with the World Organization for Early Childhood Education, and major publications. (AC)

  3. Perspectiva sobre una Personalidad Senera: Carmen Fischer Ramirez (Perspective on a Singular Personality: Carmen Fischer Ramirez).

    Science.gov (United States)

    Quezeda, Dina Alarcon

    1992-01-01

    Traces the career of Carmen Fischer Ramirez, focusing on her work in improving early childhood education in Chile. Reviews her university career, work with the World Organization for Early Childhood Education, and major publications. (AC)

  4. Novel Attrition-Resistant Fischer Tropsch Catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Weast, Logan, E.; Staats, William, R.

    2009-05-01

    There is a strong national interest in the Fischer-Tropsch synthesis process because it offers the possibility of making liquid hydrocarbon fuels from reformed natural gas or coal and biomass gasification products. This project explored a new approach that had been developed to produce active, attrition-resistant Fischer-Tropsch catalysts that are based on glass-ceramic materials and technology. This novel approach represented a promising solution to the problem of reducing or eliminating catalyst attrition and maximizing catalytic activity, thus reducing costs. The technical objective of the Phase I work was to demonstrate that glass-ceramic based catalytic materials for Fischer-Tropsch synthesis have resistance to catalytic deactivation and reduction of particle size superior to traditional supported Fischer-Tropsch catalyst materials. Additionally, these novel glass-ceramic-based materials were expected to exhibit catalytic activity similar to the traditional materials. If successfully developed, the attrition-resistant Fischer-Tropsch catalyst materials would be expected to result in significant technical, economic, and social benefits for both producers and public consumers of Fischer-Tropsch products such as liquid fuels from coal or biomass gasification. This program demonstrated the anticipated high attrition resistance of the glass-ceramic materials. However, the observed catalytic activity of the materials was not sufficient to justify further development at this time. Additional testing documented that a lack of pore volume in the glass-ceramic materials limited the amount of surface area available for catalysis and consequently limited catalytic activity. However, previous work on glass-ceramic catalysts to promote other reactions demonstrated that commercial levels of activity can be achieved, at least for those reactions. Therefore, we recommend that glass-ceramic materials be considered again as potential Fischer-Tropsch catalysts if it can be

  5. Post-traumatic growth of children affected by the Great East Japan Earthquake and their attitudes to memorial services and media coverage.

    Science.gov (United States)

    Yoshida, Hirokazu; Kobayashi, Natsuko; Honda, Nami; Matsuoka, Hiroo; Yamaguchi, Takuhiro; Homma, Hiroaki; Tomita, Hiroaki

    2016-05-01

    Post-traumatic growth (PTG) refers to positive changes that result from coping with a major life crisis or a traumatic event. Factors influencing PTG in youth have not been well characterized but could have a great impact on overall maturation. Fourth to ninth graders (n = 3337) attending elementary or junior high schools located in a district severely damaged by the Great East Japan Earthquake completed a questionnaire, including the revised Posttraumatic Growth Inventory for Children (PTGI-C-R) along with the Post Traumatic Stress Symptoms for Children 15 items (PTSSC-15), 31 months after the event. Experience of the disaster, prior traumatic experiences, and attitudes toward memories of the disaster (rumination) were scored by their caregivers and teachers, and effects of these factors on PTG were evaluated. There were no significant associations between PTGI-C-R and sex or experiences of the disaster. However, PTGI-C-R was negatively correlated with age (r = -0.132, P < 0.001). There was significant but very weak negative correlation between PTGI-C-R and PTSSC-15 among the children (r = -0.096, P < 0.001). PTGI-C-R was significantly associated with positive attitudes to memorial services (P < 0.001) and media coverage (P < 0.05). Positive attitudes to deliberate rumination may facilitate PTG in children following natural disasters. © 2016 The Authors. Psychiatry and Clinical Neurosciences © 2016 Japanese Society of Psychiatry and Neurology.

  6. Une mémoire à distances A long-distance memory. Veterans of the Great War and the memory of the 1917 mutiny

    Directory of Open Access Journals (Sweden)

    Nicolas Offenstadt

    2009-07-01

    Full Text Available Nombreux sont les anciens combattants qui ont participé aux mutineries de 1917 ou vécu ces événements avec une grande proximité. Pour autant, la transmission de la mémoire s’avère d’une grande complexité tant il est difficile d’assumer pleinement un mouvement collectif de désobéissance en pleine guerre, de lui affecter un sens stabilisé ou consensuel. Les AC témoignent des mutineries parce qu’ elles font partie de leur expérience de guerre et qu’ ils refusent en général toutes les formes de « bobards » qui enjolivent par trop ce qu’ils ont vécu. En même temps, leurs récits des révoltes de 1917 se font le plus souvent avec une mise à distance ici étudiée. On peut donc conclure à une forme de dualité mémorielle des mutineries.Many are the veterans who took part in the 1917 mutinies or who experienced them at close range. Yet, transmitting that memory proves extremely complex, so difficult it is to fully accept a mass movement of disobedience in wartime and award it a stable or consensual significance. The veterans bear witness to the 1917 mutinies as these were part of their war experience and because they generally reject any sort of «nonsense» that makes the past prettier than it actually was. At the same time, when they tell of these rebellions they usually mark their distance from their narrative - which is what is under study here. One might therefore conclude that these mutinies have become a sort of double memory.

  7. Cultural Memory on "Great" People in a "Small" Town: The Perception of King Alexander Karađorđević and Marshal Josip Broz Tito in the Cultural Memory of Samobor

    Directory of Open Access Journals (Sweden)

    Danijel Vojak

    2015-08-01

    Full Text Available Starting from the thesis that ''history is written by the winners”, ''mainstream'' history can be under¬stood as the revised and politically instrumentalized means of a certain nation's ''cultural'' memory, which some consider to be a ''history of selective memo¬ri¬zation and selective forgetfulness''. Most approaches in con¬temporary Croatian historiography which are focu¬sed on the historical periods of monarchist and socialist Yugoslavia use national-level themes as their starting point. A similar preoccupation is also present in those historiographical approaches which are focused on the problems of analyzing and understanding how collective memories are constructed. However, our aim here is to move from the ''big'' themes to a ''small'' (local setting. In this context, Samobor, a small Croatian urban centre, is going to serve us as the basis for analyzing in which way two Yugoslav rulers – King Alexander Karađorđević and Marshal Josip Broz Tito – were perceived on the local level. By analyzing the relevant archival sources as well as contemporary periodicals, we seek to un¬der¬stand the ways in which local authorities and elites, from their position of social power and status, received the mentioned rulers during their visits, and in which ways did they honour and commemorate these high-profile guests. Through this analysis, we hope to gain a better understanding of the process of the creation of local social memory, the constitution of memorial and cul¬tural patterns, and their key cultural elements and me¬anings, which are often torn apart during periods of social and political upheaval, only to be reconstituted by recombining the same key cultural and social elements while simultaneously encompassing new actors. In other words, the focus of our analysis will be on tracing the collective memory of the population of Samobor to¬wards two ''great leaders''. Starting from the thesis that ''history is written by the winners

  8. Fischer decomposition in symplectic harmonic analysis

    OpenAIRE

    Brackx, Fred; De Schepper, Hennie; Eelbode, David; Lávička, Roman; Soucek, Vladimir

    2014-01-01

    In the framework of quaternionic Clifford analysis in Euclidean space , which constitutes a refinement of Euclidean and Hermitian Clifford analysis, the Fischer decomposition of the space of complex valued polynomials is obtained in terms of spaces of so-called (adjoint) symplectic spherical harmonics, which are irreducible modules for the symplectic group Sp. Its Howe dual partner is determined to be sl(2, C) circle plus sl(2, C) = so(4, C).

  9. Effects of loading and synthesis method of titania-supported cobalt catalysts for Fischer-Tropsch synthesis

    NARCIS (Netherlands)

    Eschemann, Thomas O.; Bitter, Johannes H.; De Jong, Krijn P.

    2014-01-01

    Because of their high activity and selectivity to C5+ hydrocarbons in the Fischer-Tropsch, process, titania-supported cobalt catalysts have received great interest from industrial and academic, institutions. Here, we report on three catalyst preparation procedures, incipient wetness impregnation (IW

  10. [Determination of low-carbon alcohols, aldehydes and ketones in aqueous products of Fischer-Tropsch synthesis by gas chromatography].

    Science.gov (United States)

    Gai, Qingqing; Wu, Peng; Shi, Yulin; Bai, Yu; Long, Yinhua

    2015-01-01

    A method for the determination of low-carbon (C1-C8) alcohols, aldehydes and ketones in aqueous products of Fischer-Tropsch synthesis was developed by gas chromatography. It included the optimization of separation conditions, the precision and accuracy of determination, and the use of correction factors of the analytes to ethanol for quantification. The aqueous products showed that the correlation coefficients for ethanol in different content ranges were above 0.99, which means it had good linear correlations. The spiked recoveries in the aqueous samples of Fischer-Tropsch synthesis were from 93.4% to 109.6%. The accuracy of the method can satisfy the requirement for the analysis of the aqueous samples of Fischer-Tropsch synthesis. The results showed that the total mass fractions of the major low-carbon alcohols, aldehydes, ketones in aqueous products of Fischer-Tropsch synthesis were about 3%-12%, and the contents of ethanol were the highest (about 1.7%-7.3%). The largest share of the total proportion was n-alcohols, followed by isomeric alcohols, aldehydes and ketones were the lowest. This method is simple, fast, and has great significance for the analysis of important components in aqueous products of Fischer-Tropsch synthesis.

  11. Eli Fischer-Jørgensen, Eugeniu Coseriu et Louis Hjelmslev

    DEFF Research Database (Denmark)

    Jensen, Viggo Bank

    2015-01-01

    Based on a correspondence between Eugenio Coseriu (1921-2002) and Eli Fischer-Jørgensen (1911-2010), the article discusses the importance of Louis Hjelmslev (1899-1965) for the development of the theory of Coseriu. In a letter dated 1955, Fischer-Jørgensen agrees with Coseriu in his criticism of ...

  12. Centenary of the Battle of Vimy (france, 1917): Preserving the Memory of the Great War Through 3d Recording of the Maison Blanche Souterraine

    Science.gov (United States)

    Murtiyoso, A.; Grussenmeyer, P.; Guillemin, S.; Prilaux, G.

    2017-08-01

    The Battle of Vimy Ridge was a military engagement between the Canadian Corps and the German Empire during the Great War (1914-1918). In this battle, Canadian troops fought as a single unit and won the day. It marked an important point in Canadian history as a nation. The year 2017 marks the centenary of this battle. In commemoration of this event, the Pas-de-Calais Departmental Council financed a 3D recording mission for one of the underground tunnels (souterraines) used as refuge by the Canadian soldiers several weeks prior to the battle. A combination of Terrestrial Laser Scanner (TLS) and close-range photogrammetry techniques was employed in order to document not only the souterraine, but also the various carvings and graffitis created by the soldiers on its walls. The resulting point clouds were registered to the French national geodetic system, and then meshed and textured in order to create a precise 3D model of the souterraine. In this paper, the workflow taken during the project as well as several results will be discussed. In the end, the resulting 3D model was used to create derivative products such as maps, section profiles, and also virtual visit videos. The latter helps the dissemination of the 3D information and thus aids in the preservation of the memory of the Great War for Canada.

  13. Irene K. Fischer (1907-2009)

    Science.gov (United States)

    Morrison, Foster; Chovitz, Bernard; Fischer, Michael M. J.

    2010-05-01

    Irene Kaminka Fischer, a prominent geodesist whose career spanned the years 1952-1977, died on 22 October 2009 at the age of 102 at an assisted living facility in Brighton, Mass. Born in Vienna, Austria, on 27 July 1907, Irene grew up there; graduating with a degree in mathematics from the Vienna Institute of Technology; and met and married her husband, Eric, a noted geographer. In 1939, the Fischers fled Nazi Austria, first to Palestine, and by 1941 had relocated to the United States. During the next 11 years, Irene worked at various jobs, as well as playing the role of mother to her son and daughter. But when her daughter was ready for college, she began to look for a position that would fully utilize her considerable talents in mathematics. She found a perfect fit at her husband's federal agency, the U.S. Army Map Service (AMS). Her entire career in geodesy was spent with that organization and its successors (currently the National Geospatial-Intelligence Agency (NGA)). Hired as a mathematician, she eventually was promoted to chief of the Geoid Branch in the Geodesy Division. She retained that position until her retirement in 1977.

  14. Fischer-Tropsch synthesis. Development and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Schaub, G.; Rohde, M.; Mena Subiranas, A. [Karlsruhe Univ. (Germany). Engler-Bunte-Institut

    2006-07-01

    Production of synthetic hydrocarbons via Fischer-Tropsch (FT) synthesis has the potential to produce high-value automotive fuels and petrochemicals from fossil and renewable sources. The availability of cheap natural gas and solid raw materials like coal and biomass has given momentum to synthesis technologies first developed in the mid-twentieth century. The present paper summarizes the fundamentals and describes some general aspects regarding driving forces, catalyst and reaction, synthesis reactor, and overall process. In this way, it indicates the context of present and future developments. Worldwide plant capacities will increase significantly in the next future, with natural gas favored as feedstock. Substitution of petroleum as well as production of improved products (like automotive fuels) are the most significant incentives. Energy loss and additional fossil CO{sub 2} emissions caused by the conversion process will be a problem in extended applications with fossil feedstocks. The current R and D activities worldwide, in all areas related to Fischer-Tropsch synthesis, will contribute to further process improvements and extended applications. (orig.)

  15. Differential Gene Expression in the Nucleus Accumbens and Frontal Cortex of Lewis and Fischer 344 Rats Relevant to Drug Addiction

    Science.gov (United States)

    Higuera-Matas, A; Montoya, G. L; Coria, S.M; Miguéns, M; García-Lecumberri, C; Ambrosio, E

    2011-01-01

    Drug addiction results from the interplay between social and biological factors. Among these, genetic variables play a major role. The use of genetically related inbred rat strains that differ in their preference for drugs of abuse is one approach of great importance to explore genetic determinants. Lewis and Fischer 344 rats have been extensively studied and it has been shown that the Lewis strain is especially vulnerable to the addictive properties of several drugs when compared with the Fischer 344 strain. Here, we have used microarrays to analyze gene expression profiles in the frontal cortex and nucleus accumbens of Lewis and Fischer 344 rats. Our results show that only a very limited group of genes were differentially expressed in Lewis rats when compared with the Fischer 344 strain. The genes that were induced in the Lewis strain were related to oxygen transport, neurotransmitter processing and fatty acid metabolism. On the contrary genes that were repressed in Lewis rats were involved in physiological functions such as drug and proton transport, oligodendrocyte survival and lipid catabolism. These data might be useful for the identification of genes which could be potential markers of the vulnerability to the addictive properties of drugs of abuse. PMID:21886580

  16. Differential gene expression in the nucleus accumbens and frontal cortex of lewis and Fischer 344 rats relevant to drug addiction.

    Science.gov (United States)

    Higuera-Matas, A; Montoya, G L; Coria, S M; Miguéns, M; García-Lecumberri, C; Ambrosio, E

    2011-03-01

    Drug addiction results from the interplay between social and biological factors. Among these, genetic variables play a major role. The use of genetically related inbred rat strains that differ in their preference for drugs of abuse is one approach of great importance to explore genetic determinants. Lewis and Fischer 344 rats have been extensively studied and it has been shown that the Lewis strain is especially vulnerable to the addictive properties of several drugs when compared with the Fischer 344 strain. Here, we have used microarrays to analyze gene expression profiles in the frontal cortex and nucleus accumbens of Lewis and Fischer 344 rats. Our results show that only a very limited group of genes were differentially expressed in Lewis rats when compared with the Fischer 344 strain. The genes that were induced in the Lewis strain were related to oxygen transport, neurotransmitter processing and fatty acid metabolism. On the contrary genes that were repressed in Lewis rats were involved in physiological functions such as drug and proton transport, oligodendrocyte survival and lipid catabolism.These data might be useful for the identification of genes which could be potential markers of the vulnerability to the addictive properties of drugs of abuse.

  17. Assessment of the Extracts of Centaurea tchihatcheffii Fischer for ...

    African Journals Online (AJOL)

    Erah

    Fischer & C.A. Meyer (Asteraceae) for their anti-inflammatory and analgesic activities in male Swiss albino mice. Methods: .... conditions, maintained on standard pellet diet and given water ad ..... Edema and cell infiltration in the phorbol ester.

  18. Differential Gene Expression in the Nucleus Accumbens and Frontal Cortex of Lewis and Fischer 344 Rats Relevant to Drug Addiction

    OpenAIRE

    Higuera-Matas, A; Montoya, G. L.; Coria, S.M; Miguéns, M; García-Lecumberri, C.; Ambrosio, E.

    2011-01-01

    Drug addiction results from the interplay between social and biological factors. Among these, genetic variables play a major role. The use of genetically related inbred rat strains that differ in their preference for drugs of abuse is one approach of great importance to explore genetic determinants. Lewis and Fischer 344 rats have been extensively studied and it has been shown that the Lewis strain is especially vulnerable to the addictive properties of several drugs when compared with the Fi...

  19. Brauer-Buschke-Fischer keratoderma associated with two malignancies

    Directory of Open Access Journals (Sweden)

    C Sujatha Vinod

    2012-01-01

    Full Text Available Hereditary punctuate palmoplantar keratoderma is a rare autosomal dominantly inherited condition with variable penetrance. We report a case of a 65-year-old manual laborer who presented with multiple asymptomatic hyperkeratotic lesions on both palms and soles of about 45-year duration, which was diagnosed as Brauer-Buschke-Fischer keratoderma and was associated with squamous cell carcinoma of chest wall and ethmoidal carcinoma. This case is being presented for its rarity and the association of Brauer-Buschke-Fischer keratoderma with two malignancies in a single individual.

  20. Fischer Assays of Oil-Shale Drill Cores and Rotary Cuttings from the Greater Green River Basin, Southwestern Wyoming

    Science.gov (United States)

    ,

    2008-01-01

    Chapter 1 of this CD-ROM is a database of digitized Fischer (shale-oil) assays of cores and cuttings from boreholes drilled in the Eocene Green River oil shale deposits in southwestern Wyoming. Assays of samples from some surface sections are also included. Most of the Fischer assay analyses were made by the former U.S. Bureau of Mines (USBM) at its laboratory in Laramie, Wyoming. Other assays, made by institutional or private laboratories, were donated to the U.S. Geological Survey (USGS) and are included in this database as well as Adobe PDF-scanned images of some of the original laboratory assay reports and lithologic logs prepared by USBM geologists. The size of this database is 75.2 megabytes and includes information on 971 core holes and rotary-drilled boreholes and numerous surface sections. Most of these data were released previously by the USBM and the USGS through the National Technical Information Service but are no longer available from that agency. Fischer assays for boreholes in northeastern Utah and northwestern Colorado have been published by the USGS. Additional data include geophysical logs, groundwater data, chemical and X-ray diffraction analyses, and other data. These materials are available for inspection in the office of the USGS Central Energy Resources Team in Lakewood, Colorado. The digitized assays were checked with the original laboratory reports, but some errors likely remain. Other information, such as locations and elevations of core holes and oil and gas tests, were not thoroughly checked. However, owing to the current interest in oil-shale development, it was considered in the public interest to make this preliminary database available at this time. Chapter 2 of this CD-ROM presents oil-yield histograms of samples of cores and cuttings from exploration drill holes in the Eocene Green River Formation in the Great Divide, Green River, and Washakie Basins of southwestern Wyoming. A database was compiled that includes about 47

  1. BASELINE DESIGN/ECONOMICS FOR ADVANCED FISCHER-TROPSCH TECHNOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    None

    1998-04-01

    Bechtel, along with Amoco as the main subcontractor, developed a Baseline design, two alternative designs, and computer process simulation models for indirect coal liquefaction based on advanced Fischer-Tropsch (F-T) technology for the U. S. Department of Energy's (DOE's) Federal Energy Technology Center (FETC).

  2. God has moved. Long live the God! / Rene Fischer

    Index Scriptorium Estoniae

    Fischer, Rene

    2004-01-01

    Reklaamifirma Tank senine shveitslasest loovjuht Rene Fischer oma tööst ettevõttes, firma edukuse võimalikest põhjustest, olukorrast Baltimaade reklaamiturul, Läti reklaamifirma Bates/Red Cell loovjuhiks lahkumise põhjustest ning eesmärkidest uuel töökohal. Lisad: Other stuff; Technical data

  3. God has moved. Long live the God! / Rene Fischer

    Index Scriptorium Estoniae

    Fischer, Rene

    2004-01-01

    Reklaamifirma Tank senine shveitslasest loovjuht Rene Fischer oma tööst ettevõttes, firma edukuse võimalikest põhjustest, olukorrast Baltimaade reklaamiturul, Läti reklaamifirma Bates/Red Cell loovjuhiks lahkumise põhjustest ning eesmärkidest uuel töökohal. Lisad: Other stuff; Technical data

  4. Simulation models and designs for advanced Fischer-Tropsch technology

    Energy Technology Data Exchange (ETDEWEB)

    Choi, G.N.; Kramer, S.J.; Tam, S.S. [Bechtel Corp., San Francisco, CA (United States)

    1995-12-31

    Process designs and economics were developed for three grass-roots indirect Fischer-Tropsch coal liquefaction facilities. A baseline and an alternate upgrading design were developed for a mine-mouth plant located in southern Illinois using Illinois No. 6 coal, and one for a mine-mouth plane located in Wyoming using Power River Basin coal. The alternate design used close-coupled ZSM-5 reactors to upgrade the vapor stream leaving the Fischer-Tropsch reactor. ASPEN process simulation models were developed for all three designs. These results have been reported previously. In this study, the ASPEN process simulation model was enhanced to improve the vapor/liquid equilibrium calculations for the products leaving the slurry bed Fischer-Tropsch reactors. This significantly improved the predictions for the alternate ZSM-5 upgrading design. Another model was developed for the Wyoming coal case using ZSM-5 upgrading of the Fischer-Tropsch reactor vapors. To date, this is the best indirect coal liquefaction case. Sensitivity studies showed that additional cost reductions are possible.

  5. Overview of Fischer-Tropsch Synthesis in Slurry Reactors

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A brief review of Fischer-Tropsch synthesis specially in slurry reactors ispresented, covering reaction kinetics, activity and selectivity of catalysts, productdistribution, effects of process parameters, mass transfer and solubility of gas. Someimportant aspects of further research are proposed for improving both theories andproduction.

  6. Overview of Fischer-Tropsch Synthesis in Slurry Reactors

    Institute of Scientific and Technical Information of China (English)

    丁百全; 李涛; A.A.C.M.Beenackers; G.P.vanderLaan

    2000-01-01

    A brief review of Fischer-Tropsch synthesis specially in slurry reactors is presented, covering reaction kinetics, activity and selectivity of catalysts, product distribution, effects of process parameters, mass transfer and solubility of gas. Some important aspects of further research axe proposed for improving both theories and production.

  7. Alternative Fuel Research in Fischer-Tropsch Synthesis

    Science.gov (United States)

    Surgenor, Angela D.; Klettlinger, Jennifer L.; Yen, Chia H.; Nakley, Leah M.

    2011-01-01

    NASA Glenn Research Center has recently constructed an Alternative Fuels Laboratory which is solely being used to perform Fischer-Tropsch (F-T) reactor studies, novel catalyst development and thermal stability experiments. Facility systems have demonstrated reliability and consistency for continuous and safe operations in Fischer-Tropsch synthesis. The purpose of this test facility is to conduct bench scale Fischer-Tropsch (F-T) catalyst screening experiments while focusing on reducing energy inputs, reducing CO2 emissions and increasing product yields within the F-T process. Fischer-Tropsch synthesis is considered a gas to liquid process which reacts syn-gas (a gaseous mixture of hydrogen and carbon monoxide), over the surface of a catalyst material which is then converted into liquids of various hydrocarbon chain length and product distributions1. These hydrocarbons can then be further processed into higher quality liquid fuels such as gasoline and diesel. The experiments performed in this laboratory will enable the investigation of F-T reaction kinetics to focus on newly formulated catalysts, improved process conditions and enhanced catalyst activation methods. Currently the facility has the capability of performing three simultaneous reactor screening tests, along with a fourth fixed-bed reactor used solely for cobalt catalyst activation.

  8. Niobia-supported Cobalt Catalysts for Fischer-Tropsch Synthesis

    NARCIS (Netherlands)

    den Otter, J.H.

    2016-01-01

    In this thesis niobia has been shown to be an attractive support for application in Fischer-Tropsch catalysis at industrially relevant conditions without apparent deactivation up to at least 200 hours of operation. This proves that the level of potentially poisoning contaminants is sufficiently low

  9. Relationship between vulnerability to reinforcing effects of morphine and activity of the endogenous cholecystokinin system in Lewis and Fischer rats.

    Science.gov (United States)

    Noble, Florence; Benturquia, Nadia; Crete, Dominique; Canestrelli, Corinne; Mas Nieto, Magdalena; Wilson, Jodie; Roques, Bernard P

    2012-05-01

    A great number of studies have shown the presence of physiological interactions between brain neurotransmitter systems in behavioural responses. This is the case for opioid, cholecystokinin (CCK) and dopamine systems. However, so far the role that the CCK system may play in vulnerability to consumption of drugs of abuse is not clear. This was investigated in this study using Lewis rats that are more sensitive to the reinforcing properties of drugs of abuse than Fischer rats. The extraneuronal CCK(8) levels and brain CCK(2) receptors were found higher in Fischer than in Lewis rats in the nucleus accumbens, one of the most important structures involved in drug consumption. Moreover, pharmacological modulation of the CCK system by administration of a selective CCK(2) agonist blocked, in the conditioned place preference, the reinforcing effects of morphine in Lewis rats, whereas a selective CCK(2) antagonist revealed reinforcing effects of the alkaloid in Fischer rats. These results obtained following systemic administrations of the CCK ligands were confirmed following microinjection into the nucleus accumbens. Thus, a low level of CCK efflux in the nucleus accumbens could be one of the many factors involved in drug reinforcing effects, whereas a high level of CCK efflux could attenuate it.

  10. Fischer-Tropsch Catalyst for Aviation Fuel Production

    Science.gov (United States)

    DeLaRee, Ana B.; Best, Lauren M.; Bradford, Robyn L.; Gonzalez-Arroyo, Richard; Hepp, Aloysius F.

    2012-01-01

    As the oil supply declines, there is a greater need for cleaner alternative fuels. There will undoubtedly be a shift from crude oil to nonpetroleum sources as a feedstock for aviation (and other transportation) fuels. The Fischer-Tropsch process uses a gas mixture of carbon monoxide and hydrogen which is converted into various liquid hydrocarbons; this versatile gas-to-liquid technology produces a complex product stream of paraffins, olefins, and oxygenated compounds such as alcohols and aldehydes. The Fischer-Tropsch process can produce a cleaner diesel oil fraction with a high cetane number (typically above 70) without any sulfur and aromatic compounds. It is most commonly catalyzed by cobalt supported on alumina, silica, or titania or unsupported alloyed iron powders. Cobalt is typically used more often than iron, in that cobalt is a longer-active catalyst, has lower water-gas shift activity, and lower yield of modified products. Promoters are valuable in improving Fischer-Tropsch catalyst as they can increase cobalt oxide dispersion, enhance the reduction of cobalt oxide to the active metal phase, stabilize a high metal surface area, and improve mechanical properties. Our goal is to build up the specificity of the Fischer-Tropsch catalyst while adding less-costly transition metals as promoters; the more common promoters used in Fischer-Tropsch synthesis are rhenium, platinum, and ruthenium. In this report we will describe our preliminary efforts to design and produce catalyst materials to achieve our goal of preferentially producing C8 to C18 paraffin compounds in the NASA Glenn Research Center Gas-To-Liquid processing plant. Efforts at NASA Glenn Research Center for producing green fuels using non-petroleum feedstocks support both the Sub-sonic Fixed Wing program of Fundamental Aeronautics and the In Situ Resource Utilization program of the Exploration Technology Development and Demonstration program.

  11. Subtask 3.4 - Fischer - Tropsch Fuels Development

    Energy Technology Data Exchange (ETDEWEB)

    Strege, Joshua; Snyder, Anthony; Laumb, Jason; Stanislowski, Joshua; Swanson, Michael

    2012-05-01

    Under Subtask 3.4, the Energy & Environmental Research Center (EERC) examined the opportunities and challenges facing FischerTropsch (FT) technology in the United States today. Work was completed in two distinct budget periods (BPs). In BP1, the EERC examined the technical feasibility of using modern warm-gas cleanup techniques for FT synthesis. FT synthesis is typically done using more expensive and complex cold-gas sweetening. Warm-gas cleanup could greatly reduce capital and operating costs, making FT synthesis more attractive for domestic fuel production. Syngas was generated from a variety of coal and biomass types; cleaned of sulfur, moisture, and condensables; and then passed over a pilot-scale FT catalyst bed. Laboratory and modeling work done in support of the pilot-scale effort suggested that the catalyst was performing suboptimally with warm-gas cleanup. Long-term trends showed that the catalyst was also quickly deactivating. In BP3, the EERC compared FT catalyst results using warm-gas cleanup to results using cold-gas sweetening. A gas-sweetening absorption system (GSAS) was designed, modeled, and constructed to sweeten syngas between the gasifier and the pilot-scale FT reactor. Results verified that the catalyst performed much better with gas sweetening than it had with warm-gas cleanup. The catalyst also showed no signs of rapid deactivation when the GSAS was running. Laboratory tests in support of this effort verified that the catalyst had deactivated quickly in BP1 because of exposure to syngas, not because of any design flaw with the pilot-scale FT reactor itself. Based on these results, the EERC concludes that the two biggest issues with using syngas treated with warm-gas cleanup for FT synthesis are high concentrations of CO{sub 2} and volatile organic matter. Other catalysts tested by the EERC may be more tolerant of CO{sub 2}, but volatile matter removal is critical to ensuring long-term FT catalyst operation. This subtask was funded through

  12. Investigation of amine-buffered amide reagents for coulometric Karl Fischer titration.

    Science.gov (United States)

    Larsson, William; Cedergren, Anders

    2009-06-15

    Formamide (FA), N-methylformamide (NMF), and dimethylformamide (DMF), were evaluated as solvents for coulometric Karl Fischer (KF) reagents in combination with several amine bases. Except for the effect of the iodine species (iodine or triiodide), the pH of the reagent and the position of the sulfur dioxide/hydrogen sulfite equilibrium were found to be the main factors explaining the large difference in the observed reaction rates between water and the KF reagent in these solvents. Acid-base titrations showed that hydrogen sulfite is the main sulfur reactant in these media. The results will be of great importance in finding suitable combinations of base and solvent with respect to stoichiometry, side reactions caused by active carbonyl compounds, and reagent stability.

  13. Fischer-Tropsch synthesis on hierarchically structured cobalt nanoparticle/carbon nanofiber/carbon felt composites.

    Science.gov (United States)

    Zarubova, Sarka; Rane, Shreyas; Yang, Jia; Yu, Yingda; Zhu, Ye; Chen, De; Holmen, Anders

    2011-07-18

    The hierarchically structured carbon nanofibers (CNFs)/carbon felt composites, in which CNFs were directly grown on the surface of microfibers in carbon felt, forming a CNF layer on a micrometer range that completely covers the microfiber surfaces, were tested as a novel support material for cobalt nanoparticles in the highly exothermic Fischer-Tropsch (F-T) synthesis. A compact, fixed-bed reactor, made of disks of such composite materials, offered the advantages of improved heat and mass transfer, relatively low pressure drop, and safe handling of immobilized CNFs. An efficient 3-D thermal conductive network in the composite provided a relatively uniform temperature profile, whereas the open structure of the CNF layer afforded an almost 100 % effectiveness of Co nanoparticles in the F-T synthesis in the fixed bed. The greatly improved mass and heat transport makes the compact reactor attractive for applications in the conversion of biomass, coal, and natural gas to liquids.

  14. Nonsmooth Newton method for Fischer function reformulation of contact force problems for interactive rigid body simulation

    DEFF Research Database (Denmark)

    Silcowitz, Morten; Niebe, Sarah Maria; Erleben, Kenny

    2009-01-01

    contact response. In this paper, we present a new approach to contact force determination. We reformulate the contact force problem as a nonlinear root search problem, using a Fischer function. We solve this problem using a generalized Newton method. Our new Fischer - Newton method shows improved...... qualities for specific configurations where the most widespread alternative, the Projected Gauss-Seidel method, fails. Experiments show superior convergence properties of the exact Fischer - Newton method....

  15. Codependency and Validating Spann-Fischer in The Women of Mashhad

    OpenAIRE

    2010-01-01

    Objective: The aim of this study is validating Spann-Fischer (codependency test) and investigating the "codependency" based on characteristics of the substance abuser wives. Methods: Spann-Fischer test normalize using a sample of 507 women. A sample contain of 204 women with addicted husbands who had referred to 33 qutting centers in Mashhad were analyzed and they also were used to validate the test. Results: The results confirm the validity and reliability of Spann-Fischer test, significant...

  16. Deactivation and Regeneration of Commercial Type Fischer-Tropsch Co-Catalysts—A Mini-Review

    Directory of Open Access Journals (Sweden)

    Erling Rytter

    2015-03-01

    Full Text Available Deactivation of commercially relevant cobalt catalysts for Low Temperature Fischer-Tropsch (LTFT synthesis is discussed with a focus on the two main long-term deactivation mechanisms proposed: Carbon deposits covering the catalytic surface and re-oxidation of the cobalt metal. There is a great variety in commercial, demonstration or pilot LTFT operations in terms of reactor systems employed, catalyst formulations and process conditions. Lack of sufficient data makes it difficult to correlate the deactivation mechanism with the actual process and catalyst design. It is well known that long term catalyst deactivation is sensitive to the conditions the actual catalyst experiences in the reactor. Therefore, great care should be taken during start-up, shutdown and upsets to monitor and control process variables such as reactant concentrations, pressure and temperature which greatly affect deactivation mechanism and rate. Nevertheless, evidence so far shows that carbon deposition is the main long-term deactivation mechanism for most LTFT operations. It is intriguing that some reports indicate a low deactivation rate for multi-channel micro-reactors. In situ rejuvenation and regeneration of Co catalysts are economically necessary for extending their life to several years. The review covers information from open sources, but with a particular focus on patent literature.

  17. Separation of Fischer-Tropsch from Catalyst by Supercritical Extraction.

    Energy Technology Data Exchange (ETDEWEB)

    Joyce, P.C.; Thies, M.C.

    1997-10-31

    The objective of this research project is to evaluate the potential of supercritical fluid (SCF) extraction for the recovery and fractionation of the wax product from the slurry bubble column (SBC) reactor of the Fischer-Tropsch (F-T) process. The wax, comprised mostly of branched and linear alkanes with a broad molecular weight distribution up to C{sub 100}, will be extracted with a hydrocarbon solvent that has a critical temperature near the operating temperature of the SBC reactor, i.e., 200-300{degrees}C. Initial work is being performed using n-hexane as the solvent.

  18. HOLDING THE TORCH UP HIGH - A MEDICAL HISTORICAL EVALUATION OF SURGICAL ADVANCES DURING THE GREAT WAR 1914-1918, IN MEMORY OF THOSE THAT SERVED AND FELL.

    Science.gov (United States)

    Scharf, G

    2017-09-01

    "How wide and varied is the experience of the battlefield and how fertile the blood of warriors in raising good surgeons" Sir Clifford Allbutt (1898). With these sentiments of the medical lessons learned in war and conflict, with the background of the poem of "In Flanders Field", written by a doctor who had South African War connections, reasons (the Somme and third Ypres battles) will be given that this was indeed a "GREAT WAR" as the world history, weapons, strategy, tactics and wounding patterns had changed dramatically. These changes are still affecting all at present, as eventually the Second World War came from it, as well as the Cold "Third World" War. In this war most casualties were caused by bomb fragments and the figures were enormous. It was the war of massive troop movements (railroads), the Schlieffen plan, trench warfare, artillery, the machine guns, end of cavalry and the initiation of tanks, air warfare/reconnaissance and gas/chemical warfare. The surgical experiences of previous wars were obsolete. Urgent rethinking of surgical principles and protocols had to be devised, with the death rates of dying due to wounds, sepsis and tetanus exceeding 60 percent of all casualties. Abdominal wounds were treated conservatively, but soon there came advances in resuscitation, anaesthetics, aggressive wound and exploratory surgery, orthopaedics, plastic and reconstructive surgery, physiology, wound pathology and microbiology. All sides concentrated on ambulance stations, field hospitals and then rapid transfer to bigger referral and base hospitals. It seems that lessons learned where indeed exchanged (? by the Red Cross to all combatant medical personal). Even to the present day, frameworks of this are still used effectively (Vietnam War, Falklands War and our recent border wars). The lessons are well learned and the Torch is ours to hold up high! Copyright© Authors.

  19. Great Expectations

    NARCIS (Netherlands)

    Dickens, Charles

    2005-01-01

    One of Dickens's most renowned and enjoyable novels, Great Expectations tells the story of Pip, an orphan boy who wishes to transcend his humble origins and finds himself unexpectedly given the opportunity to live a life of wealth and respectability. Over the course of the tale, in which Pip

  20. Great Concern

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    Women of China magazine was first published in 1956. When the "cultural revolution" started in 1966 the magazine was obliged to stop publication. In 1979, when the magazine resumed publication, Mme. Soong Ching Ling, late vice chairperson of the National People’s Congress, wrote her congratulations—"Congratulations and Great Expectation."

  1. Great Expectations

    NARCIS (Netherlands)

    Dickens, Charles

    2005-01-01

    One of Dickens's most renowned and enjoyable novels, Great Expectations tells the story of Pip, an orphan boy who wishes to transcend his humble origins and finds himself unexpectedly given the opportunity to live a life of wealth and respectability. Over the course of the tale, in which Pip encount

  2. Coupling of glycerol processing with Fischer-Tropsch synthesis for production of liquid fuels

    DEFF Research Database (Denmark)

    Simonetti, D.A.; Rass-Hansen, Jeppe; Kunkes, E.L.

    2007-01-01

    % methanol, ethanol, and acetone, which can be separated from the water by distillation and used in the chemical industry or recycled for conversion to gaseous products. This integrated process has the potential to improve the economics of "green'' Fischer-Tropsch synthesis by reducing capital costs......Liquid alkanes can be produced directly from glycerol by an integrated process involving catalytic conversion to H-2/CO gas mixtures (synthesis gas) combined with Fischer-Tropsch synthesis. Synthesis gas can be produced at high rates and selectivities suitable for Fischer-Tropsch synthesis (H-2/CO......, acetone, and acetol. Fischer -Tropsch synthesis experiments at 548 K and 5 bar over a Ru-based catalyst reveal that water, ethanol, and acetone in the synthesis gas feed have only small effects, whereas acetol can participate in Fischer -Tropsch chain growth, forming pentanones, hexanones, and heptanones...

  3. 40 CFR 721.10103 - Naphtha (Fischer-Tropsch), C4-11-alkane, branched and linear.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Naphtha (Fischer-Tropsch), C4-11... Significant New Uses for Specific Chemical Substances § 721.10103 Naphtha (Fischer-Tropsch), C4-11-alkane... substance identified as naphtha (fischer-tropsch), C4-11-alkane, branched and linear (PMN P-04-235; CAS No...

  4. Great Comets

    Science.gov (United States)

    Burnham, Robert

    2000-05-01

    Spectacular and mysterious objects that come and go in the night sky, comets have dwelt in our popular culture for untold ages. As remnants from the formation of the Solar system, they are objects of key scientific research and space missions. As one of nature's most potent and dramatic dangers, they pose a threat to our safety--and yet they were the origin of our oceans and perhaps even life itself. This beautifully illustrated book tells the story of the biggest and most awe-inspiring of all comets: those that have earned the title "Great." Robert Burnham focuses on the Great comets Hyakutake in 1996 and Hale-Bopp in 1997, which gripped attention worldwide because, for many, they were the first comets ever seen. He places these two recent comets in the context of their predecessors from past ages, among them the famous Comet Halley. Great Comets explains the exciting new discoveries that have come from these magnificent objects and profiles the spaceprobes to comets due for launch in the next few years. The book even takes a peek behind Hollywood's science-fiction fantasies to assess the real risks humanity faces from potential impacts of both comets and asteroids. For everyone interested in astronomy, this exciting book reveals the secrets of the Great Comets and provides essential tools for keeping up to date with comet discoveries in the future. Robert Burnham has been an amateur astronomer since the mid-1950s. He has been a senior editor of Astronomy magazine (1986-88) and is the author of many books and CD-ROMS, including Comet Hale-Bopp: Find and Enjoy the Great Comet and Comet Explorer.

  5. Reaction rates between water and the Karl Fischer reagent.

    Science.gov (United States)

    Cedergren, A

    1974-04-01

    Reaction rates between water and the Karl Fischer reagent have been determined by potentiometric measurement for various compositions of the Karl Fischer reagent. The study has been made with an iodine complex concentration of 0.3-1.2 mM and sulphur dioxide complex at 0.01-0.5M. The concentration of excess of pyridine had no measurable effect on the rate of the main reaction. The reaction was found to be first-order with respect to iodine complex, to sulphur dioxide complex, and to water. The rate constant was (1.2+/-0.2) x 10(3) 1(2). mole(-2). sec(-1). In an ordinary titration it is therefore essential to keep the sulphur dioxide concentration high for the reaction to go to completion within a reasonable time. The extent of side-reactions was found to be independent of the iodine concentration at low concentrations. The side-reactions increased somewhat with increasing sulphur dioxide pyridine concentrations and decreased to about 60% when the temperature was lowered from 24 degrees to 7 degrees.

  6. Great Expectations for "Great Expectations."

    Science.gov (United States)

    Ridley, Cheryl

    Designed to make the study of Dickens'"Great Expectations" an appealing and worthwhile experience, this paper presents a unit of study intended to help students gain (1) an appreciation of Dickens' skill at creating realistic human characters; (2) an insight into the problems of a young man confused by false values and unreal ambitions and ways to…

  7. Great Lakes

    Science.gov (United States)

    Edsall, Thomas A.; Mac, Michael J.; Opler, Paul A.; Puckett Haecker, Catherine E.; Doran, Peter D.

    1998-01-01

    The Great Lakes region, as defined here, includes the Great Lakes and their drainage basins in Minnesota, Wisconsin, Illinois, Indiana, Ohio, Pennsylvania, and New York. The region also includes the portions of Minnesota, Wisconsin, and the 21 northernmost counties of Illinois that lie in the Mississippi River drainage basin, outside the floodplain of the river. The region spans about 9º of latitude and 20º of longitude and lies roughly halfway between the equator and the North Pole in a lowland corridor that extends from the Gulf of Mexico to the Arctic Ocean.The Great Lakes are the most prominent natural feature of the region (Fig. 1). They have a combined surface area of about 245,000 square kilometers and are among the largest, deepest lakes in the world. They are the largest single aggregation of fresh water on the planet (excluding the polar ice caps) and are the only glacial feature on Earth visible from the surface of the moon (The Nature Conservancy 1994a).The Great Lakes moderate the region’s climate, which presently ranges from subarctic in the north to humid continental warm in the south (Fig. 2), reflecting the movement of major weather masses from the north and south (U.S. Department of the Interior 1970; Eichenlaub 1979). The lakes act as heat sinks in summer and heat sources in winter and are major reservoirs that help humidify much of the region. They also create local precipitation belts in areas where air masses are pushed across the lakes by prevailing winds, pick up moisture from the lake surface, and then drop that moisture over land on the other side of the lake. The mean annual frost-free period—a general measure of the growing-season length for plants and some cold-blooded animals—varies from 60 days at higher elevations in the north to 160 days in lakeshore areas in the south. The climate influences the general distribution of wild plants and animals in the region and also influences the activities and distribution of the human

  8. "Essential oils of Heracleum Persicum Desf.ex Fischer leaves "

    Directory of Open Access Journals (Sweden)

    Mojab F

    2002-07-01

    Full Text Available The leaves of Heracleum persicum Desf ex Fischer (Syn. H glabrascens Boiss. & Hohen, H. prbescens Rech. (Fam Apiaceae were collected in July - Auguest 1993 from kandavan area in north of Tehran. The oil was extracted by hydrodistillation (0.13% from leaves and was analyzed by GC, GC/CS and 1H-NMR. The major component was trans - anethole (82.8% Other components were β - pinene, p-cymene and terpinolene (monoterpenes , α- caryophylene, α- bergamotene, α- farnesene, zingiberene, spathulenol (sesqiterpenes. Cis - anethole, stragole, 2,5-dimethyl styrene (aromatic compounds, and β- springene ( an aliphatic and hydrocarbonic diterpene . It is concluded that this oil is a source of trans - anethole .

  9. TECHNOLOGY DEVELOPMENT FOR IRON FISCHER-TROPSCH CATALYSTS

    Energy Technology Data Exchange (ETDEWEB)

    Davis, B.H.

    1998-07-22

    The goal of the proposed work described in this Final Report was the development of iron-based Fischer-Tropsch catalysts that combined high activity, selectivity and life with physical robustness for slurry phase reactors that will produce either low-alpha or high-alpha products. The work described here has optimized the catalyst composition and pretreatment operation for a low-alpha catalyst. In parallel, work has been conducted to design a high-alpha iron catalyst that is suitable for slurry phase synthesis. Studies have been conducted to define the chemical phases present at various stages of the pretreatment and synthesis stages and to define the course of these changes. The oxidation/reduction cycles that are anticipated to occur in large, commercial reactors have been studied at the laboratory scale. Catalyst performance has been determined for catalysts synthesized in this program for activity, selectivity and aging characteristics.

  10. Kinetic modelling of the Fischer-Tropsch synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Gambaro, C.; Pollesel, P.; Zennaro, R. [Eni S.p.A., San Donato Milanese (Italy); Lietti, L.; Tronconi, E. [Politecnico di Milano (Italy)

    2006-07-01

    In this work the development of a CO conversion kinetic model of the Fischer-Tropsch process will be presented. Kinetic data were produced testing a Co-based catalyst on two lab units, equipped with a slurry autoclave and a fixed bed reactor respectively. Accordingly, information on the catalytic performances of the same catalyst in two reactor configurations were also obtained. The experimental results were then analyzed with different kinetic models, available in the literature: two mechanistic models, derived by Sarup-Wojciechowski and Yates-Satterfield, and a simple power law rate expression were compared. The parameters of the different rate expressions were estimated by non-linear regression of the kinetic data collected on the two lab units. (orig.)

  11. Codependency and Validating Spann-Fischer in The Women of Mashhad

    Directory of Open Access Journals (Sweden)

    S Mhammad hasan Ashraf

    2010-11-01

    Full Text Available Objective: The aim of this study is validating Spann-Fischer (codependency test and investigating the "codependency" based on characteristics of the substance abuser wives. Methods: Spann-Fischer test normalize using a sample of 507 women. A sample contain of 204 women with addicted husbands who had referred to 33 qutting centers in Mashhad were analyzed and they also were used to validate the test. Results: The results confirm the validity and reliability of Spann-Fischer test, significant. Conclusion: The results emphasize the role of codependency as a factor against addiction treatment.

  12. New perspectives in the Fischer-Tropsch synthesis using cobalt supported on mesoporous molecular sieves; Novas perspectivas na sintese de Fischer-Tropsch usando cobalto suportado em peneiras moleculares mesoporosas

    Energy Technology Data Exchange (ETDEWEB)

    Souza, M.J.B.; Silva, A.O.S. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Dept. de Engenharia Quimica; Fernandes Junior, V.J.; Araujo, A.S. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Dept. de Quimica

    2004-07-01

    The conversion of synthesis gas to liquid products via Fischer-Tropsch synthesis (FTS) is an important process in the generation of clean fuels of sulfur and nitrogen compounds. Catalysts based on iron are very used in the conventional process due its cheap manufacture price. Recently the use of cobalt as promoter gave good results. MCM-41 mesoporous materials were discovered by Mobil scientists in the nineties and ever since they have great successes as support and catalyst in several processes of the oil industry as catalytic cracking, reformer and hydrotreating. In this work are presented new alternatives for FTS with the use of cobalt supported on molecular sieves of the type MCM-41. A comparative study with the usual catalysts based on silica was accomplished with different levels of cobalt. (author)

  13. Lipid Synthesis Under Hydrothermal Conditions by Fischer- Tropsch-Type Reactions

    Science.gov (United States)

    McCollom, Thomas M.; Ritter, Gilles; Simoneit, Bernd R. T.

    1999-03-01

    Ever since their discovery in the late 1970's, mid-ocean-ridge hydrothermal systems have received a great deal of attention as a possible site for the origin of life on Earth (and environments analogous to mid-ocean-ridge hydrothermal systems are postulated to have been sites where life could have originated on Mars and elsewhere as well). Because no modern-day terrestrial hydrothermal systems are free from the influence of organic compounds derived from biologic processes, laboratory experiments provide the best opportunity for confirmation of the potential for organic synthesis in hydrothermal systems. Here we report on the formation of lipid compounds during Fischer-Tropsch-type synthesis from aqueous solutions of formic acid or oxalic acid. Optimum synthesis occurs in stainless steel vessels by heating at 175 °C for 2-3 days and produces lipid compounds ranging from C2 to >C35 which consist of n-alkanols, n- alkanoic acids, n-alkenes, n-alkanes and alkanones. The precursor carbon sources used are either formic acid or oxalic acid, which disproportionate to H2, CO2 and probably CO. Both carbon sources yield the same lipid classes with essentially the same ranges of compounds. The synthesis reactions were confirmed by using 13C labeled precursor acids.

  14. 抗日战争纪念场馆建设的现状与思考——以平型关大捷纪念馆建设为例%Consideration on the Current Situation of Anti-Japannese War Memorial Hall——Taking Pingxingguan Great Victory Memorial Hall for an Example

    Institute of Scientific and Technical Information of China (English)

    魏晓玲

    2015-01-01

    Anti-Japannese War Memorial Hall is the document and recall of the history, which helps to diclose Japan's war crimes, rasie Chinese people's patrioism, spreda peace to the world. Therefore, Anti-Japannese War Memorial Hall construction is of great imporatance,more efforts to be made to make it work better.%抗日战争纪念场馆是记录和再现历史事件、揭露日寇罪恶、激发爱国情感、传播和平理念的重要载体,我国抗日战争场馆建设要克服对抗日战争认识的局限性,立足民族大义、秉承和平发展理念、面向世界和未来,明确建设主体,系统协调推进,拓宽场馆建设内容,更好地发挥抗日战争纪念场馆的作用.

  15. Chinese President Hu Jintao and Austrian President Heinz Fischer Send Messages of Congratulations on 2006 China Year in Austria

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    <正>Editor’s note: In January 2004, Benita Ferrero-Waldner, Austrian foreign minister at the time, announced that China Year would be held in Austria in 2006 to mark the 35th anniversary of the establishment of diplomatic relations between Austria and China and to promote understanding of China and bilateral cooperation. The two sides decided after consultation that the activities for the China Year would be jointly organized by the Austria-China Friendship Association and the Chinese People’s Association for Friendship with Foreign Countries. The governments of the two countries attach great importance to the holding of the China Year. Chinese President Hu Jintao, Austrian President Heinz Fischer and Federal Chancellor Wolfgang Schussel and other state leaders

  16. Taani tahab meid ELi kutsuda / Mariann Fischer Boel ; interv. Marianne Mikko

    Index Scriptorium Estoniae

    Fischer Boel, Mariann

    2002-01-01

    Taani põllumajandusminister Mariann Fischer Boel vastab küsimustele Eesti soovitud piimakvoodi, EL-i tulevaste liikmesriikide otsetoetuste, Taanis maa ostmise, Eesti üliliberaalse majanduse ja sotsiaalse heaolu ühendamise võimaluse kohta

  17. Different Characters of Spleen OX-62 Positive Dendritic Cells between Fischer and Lewis Rats

    Institute of Scientific and Technical Information of China (English)

    Linsong Yang; Yayi Hou

    2006-01-01

    The phenotype, DNA-binding activities of NF-κB, cytokine production, endocytosis and stimulatory capacity of spleen OX-62-positive dendritc cells (SDCs) from Fischer rats were compared with those from Lewis rats. Results showed that the expressions of CD11b, MHC-Ⅱ, CD8, CD45RA, CD54 and CD86 on SDCs were significantly higher in Fischer than those in Lewis rats. The levels of IL-2, IL-4, IL-10 and IFN-γ in SDCs from Fischer rats were distinctly higher than those from Lewis. Both stimulatory capacity and DNA-binding activities of NF-κB in SDCs were all lower in Fischer than those in Lewis rats. These differences may partly contribute to rat strainspecificity in susceptibility to chronic inflammatory stimuli.

  18. Taani tahab meid ELi kutsuda / Mariann Fischer Boel ; interv. Marianne Mikko

    Index Scriptorium Estoniae

    Fischer Boel, Mariann

    2002-01-01

    Taani põllumajandusminister Mariann Fischer Boel vastab küsimustele Eesti soovitud piimakvoodi, EL-i tulevaste liikmesriikide otsetoetuste, Taanis maa ostmise, Eesti üliliberaalse majanduse ja sotsiaalse heaolu ühendamise võimaluse kohta

  19. Combinatorial computational chemistry approach for materials design: applications in deNOx catalysis, Fischer-Tropsch synthesis, lanthanoid complex, and lithium ion secondary battery.

    Science.gov (United States)

    Koyama, Michihisa; Tsuboi, Hideyuki; Endou, Akira; Takaba, Hiromitsu; Kubo, Momoji; Del Carpio, Carlos A; Miyamoto, Akira

    2007-02-01

    Computational chemistry can provide fundamental knowledge regarding various aspects of materials. While its impact in scientific research is greatly increasing, its contributions to industrially important issues are far from satisfactory. In order to realize industrial innovation by computational chemistry, a new concept "combinatorial computational chemistry" has been proposed by introducing the concept of combinatorial chemistry to computational chemistry. This combinatorial computational chemistry approach enables theoretical high-throughput screening for materials design. In this manuscript, we review the successful applications of combinatorial computational chemistry to deNO(x) catalysts, Fischer-Tropsch catalysts, lanthanoid complex catalysts, and cathodes of the lithium ion secondary battery.

  20. The Metabolism of CIS - and Trans - Decalin in Fischer 344 Rats.

    Science.gov (United States)

    1985-12-09

    convulsions. A human with prolonged exposure to decalin was found to have intense pruritus and vesicular eczema ; the presence of albumin and leukocytes in...urine also suggested kidney involvement. (3) In 1980, Gaworski et al. reported on the subchronic inhalation toxicity of decalin in * Beagle dogs , Fischer... dogs . Pathologic studies showed no gross or microscopic lesions in these dogs . The growth of male Fischer 344 rats was retarded by exposure to decalin

  1. Succeser og fiaskoer i Fischer Boels periode som landbrugskommisær

    DEFF Research Database (Denmark)

    Kærgård, Niels; Zobbe, Henrik

    2010-01-01

    Når Mariann Fischer Boel nu overlader posten som EU's landbrugskommisær til rumæneren Dacian Ciolos, slutter endnu en periode med dansk ledelse af dette vigtige EU-område......Når Mariann Fischer Boel nu overlader posten som EU's landbrugskommisær til rumæneren Dacian Ciolos, slutter endnu en periode med dansk ledelse af dette vigtige EU-område...

  2. Some hormone, cytokine and chemokine levels that change across lifespan vary by cognitive status in male Fischer 344 rats

    Science.gov (United States)

    Scheinert, Rachel. B.; Asokan, Aditya; Rani, Asha; Kumar, Ashok; Foster, Thomas C.; Ormerod, Brandi K.

    2015-01-01

    We trained and tested young (6–8 mo; n = 13), middle-aged (12–14 mo; n = 41), and aged (22–24 mo; n = 24) male Fischer 344 rats in a rapid acquisition water maze task and then quantified 27 stress hormones, cytokines and chemokines in their serum, hippocampi and frontal cortices using bead assay kits and xMAP technology. Middle-aged and aged rats learned the location of the hidden platform over training trials more slowly than their young counterparts. After training, young rats outperformed middle-aged and aged rats on both immediate and 24h retention probe trials and about half of the middle-aged and aged (aging) rats exhibited impaired performances when tested on the retention probe trial 24h later. The concentrations of many serum, hippocampal and cortical analytes changed with age often in networks that may represent age-sensitive signaling pathways and the concentrations of some of these analytes correlated with water maze learning and/or memory scores. Serum GRO/KC and RANTES levels, hippocampal GM-CSF levels and cortical IL-9 and RANTES levels were significantly higher in rats categorized as memory-impaired versus elite agers based upon their 24h probe trial performances. Our data add to the emerging picture of how age-related changes in immune and neuroimmune system signaling impacts cognition. PMID:26093306

  3. Synthesis gas solubility in Fischer-Tropsch slurry: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Chao, K.C.; Lin, H.M.

    1988-01-01

    The objective is to investigate the phase equilibrium behavior of synthesis gases and products in a Fischer-Tropsch slurry reactor. A semi-flow apparatus has been designed and constructed for this purpose. Measurements have been made for hydrogen, cabon monoxide, methane, ethane, ethylene, and carbon dioxide in a heavy n-paraffin at temperatures from 100 to 300)degree)C and pressures 10 to 50 atm. Three n-paraffin waxes: n-eicosane (n-C/sub 20/), n-octacosane )n-C/sub 28/), and n-hexatriacontane (n-C/sub 36/), were studied to model the industrial wax. Solubility of synthesis gas mixtures of H/sub 2/ and CO in n-C/sub 28/ was also determined at two temperatures (200 and 300)degree)C) for each of three gas compositions (40.01, 50.01, and 66.64 mol%) of hydrogen). Measurements were extended to investigate the gas solubility in two industrial Fischer-Tropsch waxes: Mobilwax and SASOL wax. Observed solubility increases in the order: H/sub 2/, CO, CH/sub 4/, CO/sub 2/, C/sub 2/H/sub 4/, C/sub 2/H/sub 6/, at a given temperature pressure, and in the same solvent. Solubility increases with increasing pressure for all the gases. Lighter gases H/sub 2/ and CO show increased solubility with increasing temperature, while the heavier gases CO/sub 2/, ethane, and ethylene show decreased solubility with increasing temperature. The solubility of methane, the intermediate gas, changes little with temperature, and shows a shallow minimum at about 200)degrees)C or somewhat above. Henry's constant and partial molal volume of the gas solute at infinite dilution are determinedfrom the gas solubility data. A correlation is developed from the experimental data in the form on an equation of state. A computer program has been prepared to implement the correlation. 19 refs., 66 figs., 39 tabs.

  4. Reduction and reoxidation of cobalt Fischer-Tropsch catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Hilmen, Anne-Mette

    1996-12-31

    The Fischer-Tropsch synthesis involves the hydrogenation of carbon monoxide to produce mainly hydrocarbons, water and carbon dioxide, but also alcohols, aldehydes and acids are formed. The distribution of these products is determined by the choice of catalyst and synthesis conditions. This thesis studies the reduction and reoxidation of 17%Co/Al{sub 2}O{sub 3} and 17%Co-1%Re/Al{sub 2}O{sub 3} by means of several characterization techniques. The effect of small amounts of Re on the reduction properties of Al{sub 2}O{sub 3}-supported Co catalysts has been studied by temperature-programmed reduction (TPR). An intimate mixture of CoAl{sub 2}O{sub 3} and Re/Al{sub 2}O{sub 3} catalysts showed a promoting effect of Re similar to that for co impregnated CoRe/Al{sub 2}O{sub 3}. A loose mixture of Co/Al{sub 2}O{sub 3} + Re/Al{sub 2}O{sub 3} did not show any effect of Re on the reduction of Co. But a promoting effect was observed if the mixture had been pre-treated with Ar saturated with water before the TPR. It is suggested that Re promotes the reduction of Co oxide by hydrogen spillover. It is shown that a high temperature TPK peak at 1200K assigned to Co aluminate is mainly caused by the diffusion of Co ions during the TPR and not during calcination. The Co particle size measured by x-ray diffraction on oxidized catalysts decreased compared to the particle size on the calcined catalysts, while the dispersion measured by volumetric chemisorption decreased somewhat after the oxidation-reduction treatment. The role of water in the deactivation of Co/Al{sub 2}O{sub 3} and CoRe/Al{sub 2}O{sub 3} Fischer-Tropsch catalysts has been extensively studied. There were significant differences in the reducibility of the phases formed for the two catalysts during exposure to H{sub 2}O/He. 113 refs., 76 figs., 18 tabs.

  5. Chemical imaging of Fischer-Tropsch catalysts under operating conditions

    Science.gov (United States)

    Price, Stephen W. T.; Martin, David J.; Parsons, Aaron D.; Sławiński, Wojciech A.; Vamvakeros, Antonios; Keylock, Stephen J.; Beale, Andrew M.; Mosselmans, J. Frederick W.

    2017-01-01

    Although we often understand empirically what constitutes an active catalyst, there is still much to be understood fundamentally about how catalytic performance is influenced by formulation. Catalysts are often designed to have a microstructure and nanostructure that can influence performance but that is rarely considered when correlating structure with function. Fischer-Tropsch synthesis (FTS) is a well-known and potentially sustainable technology for converting synthetic natural gas (“syngas”: CO + H2) into functional hydrocarbons, such as sulfur- and aromatic-free fuel and high-value wax products. FTS catalysts typically contain Co or Fe nanoparticles, which are often optimized in terms of size/composition for a particular catalytic performance. We use a novel, “multimodal” tomographic approach to studying active Co-based catalysts under operando conditions, revealing how a simple parameter, such as the order of addition of metal precursors and promoters, affects the spatial distribution of the elements as well as their physicochemical properties, that is, crystalline phase and crystallite size during catalyst activation and operation. We show in particular how the order of addition affects the crystallinity of the TiO2 anatase phase, which in turn leads to the formation of highly intergrown cubic close-packed/hexagonal close-packed Co nanoparticles that are very reactive, exhibiting high CO conversion. This work highlights the importance of operando microtomography to understand the evolution of chemical species and their spatial distribution before any concrete understanding of impact on catalytic performance can be realized. PMID:28345057

  6. ATTRITION RESISTANT IRON-BASED FISCHER-TROPSCH CATALYSTS

    Energy Technology Data Exchange (ETDEWEB)

    K. Jothimurugesan; James G. Goodwin, Jr.; Santosh K. Gangwal

    1999-10-01

    Fischer-Tropsch (FT) synthesis to convert syngas (CO + H{sub 2}) derived from natural gas or coal to liquid fuels and wax is a well-established technology. For low H{sub 2} to CO ratio syngas produced from CO{sub 2} reforming of natural gas or from gasification of coal, the use of Fe catalysts is attractive because of their high water gas shift activity in addition to their high FT activity. Fe catalysts are also attractive due to their low cost and low methane selectivity. Because of the highly exothermic nature of the FT reaction, there has been a recent move away from fixed-bed reactors toward the development of slurry bubble column reactors (SBCRs) that employ 30 to 90 {micro}m catalyst particles suspended in a waxy liquid for efficient heat removal. However, the use of FeFT catalysts in an SBCR has been problematic due to severe catalyst attrition resulting in fines that plug the filter employed to separate the catalyst from the waxy product. Fe catalysts can undergo attrition in SBCRs not only due to vigorous movement and collisions but also due to phase changes that occur during activation and reaction.

  7. KINETICS OF SLURRY PHASE FISCHER-TROPSCH SYNTHESIS

    Energy Technology Data Exchange (ETDEWEB)

    Dragomir B. Bukur; Gilbert F. Froment; Lech Nowicki; Jiang Wang; Wen-Ping Ma

    2003-09-29

    This report covers the first year of this three-year research grant under the University Coal Research program. The overall objective of this project is to develop a comprehensive kinetic model for slurry phase Fischer-Tropsch synthesis on iron catalysts. This model will be validated with experimental data obtained in a stirred tank slurry reactor (STSR) over a wide range of process conditions. The model will be able to predict concentrations of all reactants and major product species (H{sup 2}O, CO{sub 2}, linear 1- and 2-olefins, and linear paraffins) as a function of reaction conditions in the STSR. During the reporting period we have completed one STSR test with precipitated iron catalyst obtained from Ruhrchemie AG (Oberhausen-Holten, Germany). This catalyst was initially in commercial fixed bed reactors at Sasol in South Africa. The catalyst was tested at 13 different sets of process conditions, and had experienced a moderate deactivation during the first 500 h of testing (decrease in conversion from 56% to 50% at baseline process conditions). The second STSR test has been initiated and after 270 h on stream, the catalyst was tested at 6 different sets of process conditions.

  8. KINETICS OF SLURRY PHASE FISCHER-TROPSCH SYNTHESIS

    Energy Technology Data Exchange (ETDEWEB)

    Dragomir B. Bukur

    2004-09-29

    This report covers the second year of this three-year research grant under the University Coal Research program. The overall objective of this project is to develop a comprehensive kinetic model for slurry phase Fischer-Tropsch synthesis on iron catalysts. This model will be validated with experimental data obtained in a stirred tank slurry reactor (STSR) over a wide range of process conditions. The model will be able to predict concentrations of all reactants and major product species (H{sub 2}O, CO{sub 2}, linear 1- and 2-olefins, and linear paraffins) as a function of reaction conditions in the STSR. During the second year of the project we completed the STSR test SB-26203 (275-343 h on stream), which was initiated during the first year of the project, and another STSR test (SB-28603 lasting 341 h). Since the inception of the project we completed 3 STSR tests, and evaluated catalyst under 25 different sets of process conditions. A precipitated iron catalyst obtained from Ruhrchemie AG (Oberhausen-Holten, Germany) was used in all tests. This catalyst was used initially in commercial fixed bed reactors at Sasol in South Africa. Also, during the second year we performed a qualitative analysis of experimental data from all three STSR tests. Effects of process conditions (reaction temperature, pressure, feed composition and gas space velocity) on water-gas-shift (WGS) activity and hydrocarbon product distribution have been determined.

  9. TECHNOLOGY DEVELOPMENT FOR IRON AND COBALT FISCHER-TROPSCH CATALYSTS

    Energy Technology Data Exchange (ETDEWEB)

    Burtron H. Davis

    1999-04-30

    The impact of activation procedure on the phase composition of precipitated iron Fischer-Tropsch (FT) catalysts has been studied. Catalyst samples taken during activation and FT synthesis have been characterized by Moessbauer spectroscopy. Formation of iron carbide is necessary for high FT activity. Hydrogen activation of precipitated iron catalysts results in reduction to predominantly metallic iron and Fe{sub 3}O{sub 4}. Metallic iron is not stable under FT 3 4 conditions and is rapidly converted to {epsilon}{prime}-Fe{sub 2.2}C. Activation with carbon monoxide or syngas 2.2 with low hydrogen partial pressure reduces catalysts to {chi}-Fe{sub 5}C{sub 2} and a small amount of 5 2 superparamagnetic carbide. Exposure to FT conditions partially oxidizes iron carbide to Fe{sub 3}O{sub 4}; however, catalysts promoted with potassium or potassium and copper maintain a constant carbide content and activity after the initial oxidation. An unpromoted iron catalyst which was activated with carbon monoxide to produce 94% {chi}-Fe{sub 5}C{sub 2}, deactivated rapidly as the carbide was oxidized to Fe{sub 3}O{sub 4}. No difference in activity, stability or deactivation rate was found for {chi}-Fe{sub 5}C{sub 2} and {epsilon}{prime}-Fe{sub 2.2}C.

  10. Age Dependent Variability in Gene Expression in Fischer 344 ...

    Science.gov (United States)

    Recent evidence suggests older adults may be a sensitive population with regard to environmental exposure to toxic compounds. One source of this sensitivity could be an enhanced variability in response. Studies on phenotypic differences have suggested that variation in response does increase with age. However, few reports address the question of variation in gene expression as an underlying cause for increased variability of phenotypic response in the aged. In this study, we utilized global analysis to compare variation in constitutive gene expression in the retinae of young (4 mos), middle-aged (11 mos) and aged (23 mos) Fischer 344 rats. Three hundred and forty transcripts were identified in which variance in expression increased from 4 to 23 mos of age, while only twelve transcripts were found for which it decreased. Functional roles for identified genes were clustered in basic biological categories including cell communication, function, metabolism and response to stimuli. Our data suggest that population stochastically-induced variability should be considered in assessing sensitivity due to old age. Recent evidence suggests older adults may be a sensitive population with regard to environmental exposure to toxic compounds. One source of this sensitivity could be an enhanced variability in response. Studies on phenotypic differences have suggested that variation in response does increase with age. However, few reports address the question of variation in

  11. Technology development for iron Fischer-Tropsch catalysts

    Energy Technology Data Exchange (ETDEWEB)

    O`Brien, R.J.; Raje, A.; Keogh, R.A. [and others

    1995-12-31

    The objective of this research project is to develop the technology for the production of physically robust iron-based Fischer-Tropsch catalysts that have suitable activity, selectivity and stability to be used in the slurry phase synthesis reactor development. The catalysts that are developed shall be suitable for testing in the Advanced Fuels Development Facility at LaPorte, Texas, to produce either low-or high-alpha product distributions. Previous work by the offeror has produced a catalyst formulation that is 1.5 times as active as the {open_quotes}standard-catalyst{close_quotes} developed by German workers for slurry phase synthesis. In parallel, work will be conducted to design a high-alpha iron catalyst this is suitable for slurry phase synthesis. Studies will be conducted to define the chemical phases present at various stages of the pretreatment and synthesis stages and to define the course of these changes. The oxidation/reduction cycles that are anticipated to occur in large, commercial reactors will be studied at the laboratory scale. Catalyst performance will be determined for catalysts synthesized in this program for activity, selectivity and aging characteristics.

  12. The Fischer 344 rat as a model of presbycusis.

    Science.gov (United States)

    Syka, Josef

    2010-06-01

    Due to the rising number of the aged human population all over the world, presbycusis is a phenomenon that deserves the increasing attention of the medical community as regards to prevention and treatment. This requires finding appropriate animal models for human presbycusis that will be useful in future experiments. Among the available rat strains, the Fischer 344 (F344) strain promises to serve as a model producing prompt and profound presbycusis. Hearing thresholds begin to increase in this strain during the first year of life; toward the end of the second year, the thresholds are very high. The threshold shifts progress independently in both ears. The rapid deterioration of distortion product otoacoustic emissions, with the majority of outer hair cells (OHC) being present and morphologically intact, is apparently produced by the disruption of prestin. The age-related changes within inner ear function are accompanied by deterioration of acoustical signal processing within central auditory system, mainly due to impaired GABA inhibition. The loss of GABA inhibition in old animals is expressed primarily in the inferior colliculus but is also present in the cochlear nuclei and the auditory cortex. Sound-evoked behavioral reactions are also impaired in old F344 rats. Taken together, the described characteristics of the aging F344 rat auditory system supports the idea that this strain may serve as a suitable model for studying the mechanisms of presbycusis, its prevention and treatment.

  13. Nanostructured Thin Films Obtained from Fischer Aminocarbene Complexes

    Directory of Open Access Journals (Sweden)

    Rosa E. Lazo-Jiménez

    2016-03-01

    Full Text Available The synthesis of four amphiphilic organometallic complexes with the general formula RC = M(CO5NH(CH215CH3, where R is a ferrocenyl 2(a-b or a phenyl 4(a-b group as a donor moiety and a Fischer carbene of chromium (0 or tungsten (0 as an acceptor group, are reported. These four push-pull systems formed Langmuir (L monolayers at the air-water interface, which were characterized by isotherms of surface pressure versus molecular area and compression/expansion cycles (hysteresis curves; Brewster angle microscopic images were also obtained. By using the Langmuir–Blodgett (LB method, molecular monolayers were transferred onto glass substrates forming Z-type multilayers. LB films were characterized through ultraviolet-visible spectroscopy, atomic force microscopy and X-ray diffraction techniques. Results indicated that films obtained from 2b complex [(Ferrocenyl(hexadecylaminemethylidene] pentacarbonyl tungsten (0 are the most stable and homogeneous; due to their properties, these materials may be incorporated into organic electronic devices.

  14. Aging increases upper airway collapsibility in Fischer 344 rats.

    Science.gov (United States)

    Ray, Andrew D; Ogasa, Toshiyuki; Magalang, Ulysses J; Krasney, John A; Farkas, Gaspar A

    2008-11-01

    The upper airway muscles play an important role in maintaining upper airway collapsibility, and the incidence of sleep-disordered breathing increases with age. We hypothesize that the increase in airway collapsibility with increasing age can be linked to changes in upper airway muscle mechanics and structure. Eight young (Y: 6 mo) and eight old (O: 30 mo) Fischer 344 rats were anesthetized and mechanically ventilated, and the pharyngeal pressure associated with flow limitation (Pcrit) was measured 1) with the hypoglossal (cnXII) nerve intact, 2) following bilateral cnXII denervation, and 3) during cnXII stimulation. With the cnXII intact, the upper airways of older rats were more collapsible compared with their younger counterparts [Pcrit = -7.1 +/- 0.6 (SE) vs. -9.5 +/- 0.7 cmH2O, respectively; P = 0.033]. CnXII denervation resulted in an increase in Pcrit such that Pcrit became similar in both groups (O: -4.2 +/- 0.5 cmH2O; Y: -5.4 +/- 0.5 cmH2O). In all rats, cnXII stimulation decreased Pcrit (less collapsible) in both groups (O: -11.3 +/- 1.0 cmH2O; Y: -10.2 +/- 1.0 cmH2O). The myosin heavy chain composition of the genioglossus muscle demonstrated a decrease in the percentage of the IIb isoform (38.3 +/- 2.5 vs. 21.7 +/- 1.7%; P collapsible with age and that the increase in upper airway collapsibility with age is likely related to altered neural control rather than to primary alterations in upper airway muscle structure and function.

  15. Neck Kaposiform haemangioendothelioma in a Fischer's lovebird (Agapornis fischeri).

    Science.gov (United States)

    Rossi, Giacomo; Galosi, Livio; Berardi, Sara; Piano, Maria Assunta; Robino, Patrizia; Rose, Timothy; Calabrò, Maria Luisa

    2016-06-01

    A six-year-old female Fischer's lovebird (Agapornis fischeri) presented at necropsy with a cutaneous mass on the neck, 3.5cm in diameter, yielding and with blood content. Histopathological findings showed a neoplasm characterized by proliferation of vascular endothelial cells. The histology of the mass revealed a multinodular, focally infiltrating tumor. Deeper dermal nodules were made of spindle cells forming vascular slits reminiscent of the histology seen in Kaposi's sarcoma (KS). More superficially located dermal nodules consisted of small blood vessels, with histology resembling capillary hemangioma. The spindle cells and capillaries were strongly positive for Vimentin, endothelial cell marker CD31, and negative for sarcomeric α-smooth muscle actin (α-SMA). Intravascular platelet trapping and Periodic acid-Schiff (PAS)-positive hyaline globules were also observed. Differential diagnosis included Kaposi's sarcoma, capillary haemangioma, spindle cell haemangioendothelioma, and epithelioid haemangioendothelioma. Based on morphological and immunohistochemical findings, the tumor was diagnosed as a cutaneous Kaposiform haemangioendothelioma (KHE), a rare, low-grade malignant vascular neoplasm. Other organs showed no abnormalities. PCR amplifications, conducted using Kaposi's sarcoma-associated herpesvirus (KSHV)-specific primers and degenerate sets of primers designed to detect and characterize members of the Herpesviridae, on DNA extracted from tumor tissue and from whole blood failed to amplify any KSHV-related sequence. Moreover, no specific signal was obtained using primers for detection of psittacine herpesvirus, known to be linked to Pacheco's disease in parrots. To the best of our knowledge, this unusual case is the third report of KHE in a non-human animal species, the first described in a bird. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Fischer-Tropsch synthesis in supercritical fluids. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Akgerman, A.; Bukur, D.B.

    1998-12-31

    The objective of this study was to investigate Fischer-Tropsch Synthesis (FTS) in the supercritical phase employing a commercial precipitated iron catalysts. As the supercritical fluid the authors used propane and n-hexane. The catalyst had a nominal composition of 100 Fe/5 Cu/4.2 K/25 SiO{sub 2} on mass basis and was used in a fixed bed reactor under both normal (conventional) and supercritical conditions. Experimental data were obtained at different temperatures (235 C, 250 C, and 260 C) and synthesis gas feed compositions (H{sub 2}/CO molar feed ratio of 0.67, 1.0 and 2.0) in both modes of operation under steady state conditions. The authors compared the performance of the precipitated iron catalyst in the supercritical phase, with the data obtained in gas phase (fixed bed reactor) and slurry phase (STS reactor). Comparisons were made in terms of bulk catalyst activity and various aspects of product selectivity (e.g. lumped hydrocarbon distribution and olefin content as a function of carbon number). In order to gain better understanding of the role of intraparticle mass transfer during FTS under conventional or supercritical conditions, the authors have measured diffusivities of representative hydrocarbon products in supercritical fluids, as well as their effective diffusion rates into the pores of catalyst at the reaction conditions. They constructed a Taylor dispersion apparatus to measure diffusion coefficients of hydrocarbon products of FTS in sub and supercritical ethane, propane, and hexane. In addition, they developed a tracer response technique to measure the effective diffusivities in the catalyst pores at the same conditions. Based on these results they have developed an equation for prediction of diffusion in supercritical fluids, which is based on the rough hard sphere theory.

  17. Progress in Karl Fischer coulometry using diaphragm-free cells.

    Science.gov (United States)

    Cedergren, A; Jonsson, S

    2001-11-15

    Different designs of a semiopen, drainable cathode compartment of a medium-sized coulometric Karl Fischer (KF) cell for the determination of water in the range 0.1-500 microg were evaluated. The main criterion for the design was to keep the resistance between the anolyte and catholyte low enough to permit the generation of currents larger than 20 mA (for an output voltage of 28 V). It was found that a good compromise between the size of this current and a minimal influence from diffusing/migrating oxidizable reduction products from the catholyte was achieved by means of an interface having a channel length and diameter of 8 and 2.1 mm, respectively (catholyte volume, approximately 1 mL). To show the general applicability of the concept, the following different types of coulometric reagents suitable for nonpolar and polar samples, as well as for samples containing active carbonyl compounds, were investigated: Hydranal Coulomat A, AD, AK, AG-H (modified with chloroform, Merck), and two homemade methanolic reagents modified with 40% (v/v) chloroform and 50% (v/v) formamide, respectively. Except for Hydranal Coulomat A, the mean value of five consecutive titrations of 50 microg water did not deviate by more than 0.2% from the expected value for all reagents. Draining after every titration was sufficient to obtain accurate results, even for Coulomat A which, when used in the commercial diaphragm-free system of Metrohm, gave values which were about 10% too high. As compared to earlier reported results for diaphragm-free coulometry, the descibed modified cell represents a significant improvement, mainly because of the high accuracy achieved for all types of reagents.

  18. Memory engram storage and retrieval.

    Science.gov (United States)

    Tonegawa, Susumu; Pignatelli, Michele; Roy, Dheeraj S; Ryan, Tomás J

    2015-12-01

    A great deal of experimental investment is directed towards questions regarding the mechanisms of memory storage. Such studies have traditionally been restricted to investigation of the anatomical structures, physiological processes, and molecular pathways necessary for the capacity of memory storage, and have avoided the question of how individual memories are stored in the brain. Memory engram technology allows the labeling and subsequent manipulation of components of specific memory engrams in particular brain regions, and it has been established that cell ensembles labeled by this method are both sufficient and necessary for memory recall. Recent research has employed this technology to probe fundamental questions of memory consolidation, differentiating between mechanisms of memory retrieval from the true neurobiology of memory storage.

  19. Recent advances on Fischer-Tropsch synthesis in micro-reactor%微反应器技术在Fischer-Tropsch合成中的应用进展

    Institute of Scientific and Technical Information of China (English)

    徐润; 胡志海; 聂红

    2016-01-01

    微反应器可以通过改善传质和传热而强化反应过程,为Fischer-Tropsch合成技术的发展提供了新的机遇。本文简要回顾了微反应器的研究及发展过程,从微反应器的本质特点着手,介绍了微反应器技术在Fischer-Tropsch合成中的应用进展。Fischer-Tropsch合成微反应器结构经历了从单通道、多通道、复合通道结构的研究过程,催化剂也开发有填充型和涂覆型两类。根据微反应器的特点,催化剂开发也取得了显著进步,与传统催化剂相比,微通道催化剂的活性可以达到固定床的8~10倍。反应器模型和数值模拟工作可以辅助实验研究,提供温度、浓度、压力等分布参数,有利于反应器设计。最后介绍了目前微反应器 Fischer-Tropsch 合成技术的中试及工业应用情况。通过对上述内容的总结,对微反应器Fischer-Tropsch合成研究和发展进行了展望。%The mass transfer and heat transfer of the chemical reaction can be improved by micro-reactor technology,which provides a new platform for Fischer-Tropsch synthesis. This paper reviews the researches and development of micro-reactor technology in the recent year and the Fischer-Tropsch synthesis in micro-reactor. The structure researches of micro-reaction devices have gone through the developments of single channel,multi channel and complex channel. The catalysts can be divided into two categories of micro particle and wall coating. Along with developments of micro reactor,the catalysts studies have also made significant progress. The activity of catalysts in micro-reaction device is 8 to 10 times higher than that in fixed-bed reactor. The studies of numerical analysis are summarized. This paper also introduces the status of pilot test and commercialization of Fischer-Tropsch synthesis in micro-reactor. It is expected the Fischer-Tropsch synthesis in micro-reactor will have a deeper development in future.

  20. Coulometric determination of trace water in active carbonyl compounds using modified Karl Fischer reagents

    Energy Technology Data Exchange (ETDEWEB)

    Nordin-Andersson, I.; Cedergren, A.

    1987-03-01

    Improved conditions for the coulometric determination of trace water in samples containing potentially interfering substances like aldehydes and ketones were obtained by using a formamide-based, rapidly reacting Karl Fischer reagent in which methanol was replaced by 2-methoxyethanol. The shape of the potentiometric titration curves obtained by titrating spent Karl Fischer reagents with iodine indicates a less degree of triiodide formation in the presence of formamide. The corresponding increase in iodine results in a more rapid overall reaction rate since the reaction involving iodine is much more rapid than that with triiodide. For water amounts corresponding to less than 0.1% the stoichiometry of the Karl Fischer reaction was found to be 1:1, relatively independent of the concentration of 2-methoxyethanol. For larger amounts of water this stoichiometric ratio was attained by using a reagent containing 2-methoxyethanol/formamide 80/20 (v/v), 0.6 M imidazole, and 0.4 M sulfur dioxide.

  1. Geohydrology and vertical distribution of volatile organic compounds in ground water, Fischer and Porter Company Superfund Site, Warminster, Bucks County, Pennsylvania

    Science.gov (United States)

    Sloto, R.A.; Macchiaroli, Paola; Conger, R.W.

    1995-01-01

    The Fischer and Porter company Superfund Site is underlain by sedimentary rocks of the Upper Triassic Stockton Formation, which consists of interbedded siltstone, very-fine grained to coarse-grained sandstone, and conglomerate in crudely defined upward fining cycles. These rocks form a complex, heterogeneous, leaky, multiaquifer system comprised of a series of gently dipping lithologic units with different hydraulic properties. Ground water is unconfined in the shallower part of the aquifer and confined or semiconfined in the deeper part of the aquifer. Water levels measured in monitor well clusters and borehole-flow measurements made in open boreholes show a downward hydraulic head gradient at the site, caused in part by the pumping of nearby, deep public-supply wells and the Fischer and Porter treatment system extraction wells. Downward borehole flow was measured at rates up to 9 gallons per minute. Aquifer-isolation tests were run in the six boreholes to obtain depth-discrete specific-capacity and water-quality data. On the basis of specific-capacity data for 27 isolated intervals, specific capacity is not related to depth. Water levels in monitor wells at the Fischer and Porter Site are greatly affected by the pumping of nearby public-supply wells, as well as the pumping of the Fischer and Porter treatment system extraction wells. Pumping of the public-supply wells causes daily water-level fluctuations in wells at the site as great as 5.3 feet. The shutdown of the Fischer and Porter treatment system extraction wells caused a rise in water level in all wells screened in the intermediate and deep zones. The rise in water level was as great as 4.3 feet in the intermediate zone and as great as 5.9 feet in the deep zone. The direction of ground-water flow is toward the north in the shallow and intermediate zones and toward the west and west-southwest in the deep zone. Ground-water discharge probably is to the unnamed tributary to Pennypack Creek north and west of

  2. Physiatrie and German maternal feminism: Dr. Anna Fischer-Dückelmann critiques academic medicine.

    Science.gov (United States)

    Meyer, Paulette

    2006-01-01

    Alternative medicine and reform strategies made Anna Fischer-Dückelmann a most controversial, notorious, and widely read women doctor before World War I. She published a dozen titles in 13 languages asserting that national well-being depended on maternal prowess. To her critics, Fischer-Dückelmann's commitment to medical self-help and practices of Physiatrie amounted to medical quackery. Her career has been largely unexamined, yet her feminist critiques and social concerns are not far removed from modern social medicine. For this pioneering doctor, treating physical and emotional ills and promoting the health of families were first steps toward healing the divisions of a world at war.

  3. Fischer-Tropsch synthesis. Evaluation of an aluminum small channel reactor.

    Science.gov (United States)

    Sparks, D E; Vallee, S; Jia, Zhijun; Shafer, W D; Davis, B H

    2017-02-10

    Fischer-Tropsch synthesis was conducted in a small channel compact heat exchange reactor that was constructed of aluminum. While limited to lower temperature-pressure regions of the Fischer-Tropsch synthesis, the reactor could be operated in an isothermal mode with nearly a constant temperature along the length of the channel. The results obtained with the compact heat exchange reactor were similar to those obtained in the isothermal continuous stirred tank reactor, with respect to both activity and selectivity. Following a planned or unplanned shutdown, the reactor could be restarted to produce essentially the same catalytic activity and selectivity as before the shutdown.

  4. Fischer-Tropsch Reaction Kinetics of Cobalt Catalyst in Supercritical Phase

    Institute of Scientific and Technical Information of China (English)

    Abdullah Irankhah; Ali Haghtalab; Ebrahim Vasheghani Farahani; Kambiz Sadaghianizadeh

    2007-01-01

    Fischer-Tropsch synthesis under supercritical phase condition was examined in a continuous and a high-pressure fixed bed reactor by employing a cobalt catalyst (Co-Ru/γ-Al2O3). An integral reactor model involving Fischer-Tropsch reaction kinetics in the supercritical fluid n-hexane was used to describe the overall performance. On the basis of Langmuir-Hinshelwood-Hougen-Watson (LHHW) model, the reaction rate constants were obtained for the rate equations of CO conversion to CH4 formation under supercritical conditions.

  5. Fly ash zeolite catalyst support for Fischer-Tropsch synthesis

    Science.gov (United States)

    Campen, Adam

    This dissertation research aimed at evaluating a fly ash zeolite (FAZ) catalyst support for use in heterogeneous catalytic processes. Gas phase Fischer-Tropsch Synthesis (FTS) over a fixed-bed of the prepared catalyst/FAZ support was identified as an appropriate process for evaluation, by comparison with commercial catalyst supports (silica, alumina, and 13X). Fly ash, obtained from the Wabash River Generating Station, was first characterized using XRD, SEM/EDS, particle size, and nitrogen sorption techniques. Then, a parametric study of a two-step alkali fusion/hydrothermal treatment process for converting fly ash to zeolite frameworks was performed by varying the alkali fusion agent, agent:flyash ratio, fusion temperature, fused ash/water solution, aging time, and crystallization time. The optimal conditions for each were determined to be NaOH, 1.4 g NaOH: 1 g fly ash, 550 °C, 200 g/L, 12 hours, and 48 hours. This robust process was applied to the fly ash to obtain a faujasitic zeolite structure with increased crystallinity (40 %) and surface area (434 m2/g). Following the modification of fly ash to FAZ, ion exchange of H+ for Na+ and cobalt incipient wetness impregnation were used to prepare a FTS catalyst. FTS was performed on the catalysts at 250--300 °C, 300 psi, and with a syngas ratio H2:CO = 2. The HFAZ catalyst support loaded with 11 wt% cobalt resulted in a 75 % carbon selectivity for C5 -- C18 hydrocarbons, while methane and carbon dioxide were limited to 13 and 1 %, respectively. Catalyst characterization was performed by XRD, N2 sorption, TPR, and oxygen pulse titration to provide insight to the behavior of each catalyst. Overall, the HFAZ compared well with silica and 13X supports, and far exceeded the performance of the alumina support under the tested conditions. The successful completion of this research could add value to an underutilized waste product of coal combustion, in the form of catalyst supports in heterogeneous catalytic processes.

  6. KINETICS OF SLURRY PHASE FISCHER-TROPSCH SYSTHESIS

    Energy Technology Data Exchange (ETDEWEB)

    Dragomir B. Bukur; Gilbert F. Froment; Tomasz Olewski

    2005-09-29

    This report covers the third year of this research grant under the University Coal Research program. The overall objective of this project is to develop a comprehensive kinetic model for slurry phase Fischer-Tropsch synthesis (FTS) on iron catalysts. This model will be validated with experimental data obtained in a stirred tank slurry reactor (STSR) over a wide range of process conditions. The model will be able to predict molar flow rates and concentrations of all reactants and major product species (H{sub 2}O, CO{sub 2}, linear 1- and 2-olefins, and linear paraffins) as a function of reaction conditions in the STSR. During the reporting period we utilized experimental data from the STSR, that were obtained during the first two years of the project, to perform vapor-liquid equilibrium (VLE) calculations and estimate kinetic parameters. We used a modified Peng-Robinson (PR) equation of state (EOS) with estimated values of binary interaction coefficients for the VLE calculations. Calculated vapor phase compositions were in excellent agreement with experimental values from the STSR under reaction conditions. Occasional discrepancies (for some of the experimental data) between calculated and experimental values of the liquid phase composition were ascribed to experimental errors. The VLE calculations show that the vapor and the liquid are in thermodynamic equilibrium under reaction conditions. Also, we have successfully applied the Levenberg-Marquardt method (Marquardt, 1963) to estimate parameters of a kinetic model proposed earlier by Lox and Froment (1993b) for FTS on an iron catalyst. This kinetic model is well suited for initial studies where the main goal is to learn techniques for parameter estimation and statistical analysis of estimated values of model parameters. It predicts that the chain growth parameter ({alpha}) and olefin to paraffin ratio are independent of carbon number, whereas our experimental data show that they vary with the carbon number

  7. KINETICS OF SLURRY PHASE FISCHER-TROPSCH SYNTHESIS

    Energy Technology Data Exchange (ETDEWEB)

    Dragomir B. Bukur; Gilbert F. Froment; Tomasz Olewski

    2006-09-29

    This report covers the fourth year of a research project conducted under the University Coal Research Program. The overall objective of this project is to develop a comprehensive kinetic model for slurry-phase Fischer-Tropsch synthesis (FTS) employing iron-based catalysts. This model will be validated with experimental data obtained in a stirred-tank slurry reactor (STSR) over a wide range of process conditions. The model will be able to predict molar flow rates and concentrations of all reactants and major product species (water, carbon dioxide, linear 1- and 2-olefins, and linear paraffins) as a function of reaction conditions in the STSR. During the fourth year of the project, an analysis of experimental data collected during the second year of this project was performed. Kinetic parameters were estimated utilizing product distributions from 27 mass balances. During the reporting period two kinetic models were employed: a comprehensive kinetic model of Dr. Li and co-workers (Yang et al., 2003) and a hydrocarbon selectivity model of Van der Laan and Beenackers (1998, 1999) The kinetic model of Yang et al. (2003) has 24 parameters (20 parameters for hydrocarbon formation, and 4 parameters for the water-gas-shift (WGS) reaction). Kinetic parameters for the WGS reaction and FTS synthesis were estimated first separately, and then simultaneously. The estimation of these kinetic parameters employed the Levenberg-Marquardt (LM) method and the trust-region reflective Newton large-scale (LS) method. A genetic algorithm (GA) was incorporated into estimation of parameters for FTS reaction to provide initial estimates of model parameters. All reaction rate constants and activation energies were found to be positive, but at the 95% confidence level the intervals were large. Agreement between predicted and experimental reaction rates has been fair to good. Light hydrocarbons are predicted fairly accurately, whereas the model underpredicts values of higher molecular weight

  8. Certification of the reference material of water content in water saturated 1-octanol by Karl Fischer coulometry, Karl Fischer volumetry and quantitative nuclear magnetic resonance.

    Science.gov (United States)

    Wang, Haifeng; Ma, Kang; Zhang, Wei; Li, Jia; Sun, Guohua; Li, Hongmei

    2012-10-15

    Certified reference materials (CRMs) of water content are widely used in the calibration and validation of Karl Fischer coulometry and volumetry. In this study, the water content of the water saturated 1-octanol (WSO) CRM was certified by Karl Fischer coulometry, volumetry and quantitative nuclear magnetic resonance (Q NMR). The water content recovery by coulometry was 99.76% with a diaphragm-less electrode and Coulomat AG anolyte. The relative bias between the coulometry and volumetry results was 0.06%. In Q NMR, the water content of WSO is traceable to the International System (SI) of units through the purity of internal standard. The relative bias of water content in WSO between Q NMR and volumetry was 0.50%. The consistency of results for these three independent methods improves the accuracy of the certification of the RM. The certified water content of the WSO CRM was 4.76% with an expanded uncertainty of 0.09%.

  9. From Fischer Tropsch raw products to Fischer Tropsch fuels. Development of an upgrading model and application to XtL processes

    Energy Technology Data Exchange (ETDEWEB)

    Beiermann, D. [Volkswagen AG, Wolfsburg (Germany)

    2007-07-01

    Within the EU-project RENEW (supported under the European Commission's 6th framework programme) an upgrading model for the conversion of Fischer Tropsch rawproducts to Fischer Tropsch fuels was developed and simulated with the process simulation software CHEMCAD. The model allowed - based on process parameters of the inputstreams - the calculation of the resulting amounts of diesel, naphtha and electricity out of the arising offgases. In addition the energy and the hydrogen demand for the upgrading process can be calculated. Furthermore a classification in thermal and electric power demand and production respectively is done. A plausibility check by means of energy consumption of different oil refineries validated the developed model. Concluding a TCI cost calculation shows the corresponding capital costs of such an upgrading unit. So beside closing the mass and energy balance, the developed model can also be used for economic calculation of XtL concepts with the aim of maximised liquid fuel production, starting from Fischer Tropsch rawproducts. (orig.)

  10. Photography as object and resource of memory

    OpenAIRE

    Felizardo, Adair; Universidade Federal de Santa Catarina; Samain, Etienne; Universidade de Campinas

    2007-01-01

    With the rise of digital photography, its ease, potentials and weaknesses, we have become more and more liable to the iconographic forgetting of our own memory, our photographic memory. This essay intends to discuss the value and the use of photography as one of the great memory-bearing instruments, own memory, memory to be clarified, interpreted, remembered. Com o advento da fotografia digital, suas facilidades, potencialidades e fragilidades, ficamos suscetíveis ao esquecimento iconográf...

  11. The Great Recession was not so Great

    NARCIS (Netherlands)

    van Ours, J.C.

    2015-01-01

    The Great Recession is characterized by a GDP-decline that was unprecedented in the past decades. This paper discusses the implications of the Great Recession analyzing labor market data from 20 OECD countries. Comparing the Great Recession with the 1980s recession it is concluded that there is a hi

  12. [In memory of A.O. Vereshchinskiĭ--a great colleague with a tragic fate at the N. N. Petrov Oncology Research Institute--at the 120th anniversary of his birth].

    Science.gov (United States)

    Pliss, G B

    2014-01-01

    The most tragic for the history of any community is a loss of memory or its distortion. Unfortunately we often forget that we grow on the shoulders of previous generations, on their achievements and mistakes. In this regard it would be good to remember our friend, colleague A.O.Vereshchynsky who would have been 120 this year.

  13. Serotonin transporter and memory.

    Science.gov (United States)

    Meneses, Alfredo; Perez-Garcia, Georgina; Ponce-Lopez, Teresa; Tellez, Ruth; Castillo, Carlos

    2011-09-01

    The serotonin transporter (SERT) has been associated to diverse functions and diseases, though seldom to memory. Therefore, we made an attempt to summarize and discuss the available publications implicating the involvement of the SERT in memory, amnesia and anti-amnesic effects. Evidence indicates that Alzheimer's disease and drugs of abuse like d-methamphetamine (METH) and (+/-)3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") have been associated to decrements in the SERT expression and memory deficits. Several reports have indicated that memory formation and amnesia affected the SERT expression. The SERT expression seems to be a reliable neural marker related to memory mechanisms, its alterations and potential treatment. The pharmacological, neural and molecular mechanisms associated to these changes are of great importance for investigation.

  14. Heterosexual Persons' Perceptions Regarding Language Use in Counseling: Extending Dorland and Fischer (2001)

    Science.gov (United States)

    Ross, Amanda D.; Waehler, Charles A.; Gray, Torie N.

    2013-01-01

    An important original study by Dorland and Fischer noted how the use of inclusive language can affect the therapeutic relationship positively for gay, lesbian, and bisexual clients. In this extension of that study with heterosexual participants ("N" = 179), there seemed to be low, but positive, salience of the language used by the…

  15. Osteochondroma of the tracheal wall in a Fischer's lovebird (Agapornis fischeri, Reichenow 1887).

    Science.gov (United States)

    Weissengruber, G; Loupal, G

    1999-01-01

    A Fischer's lovebird with dyspnea and stridorous breathing was examined by endoscopy. Tracheal stenosis was observed slightly cranial of the middle of the cervical segment. Histologically, an osteochondroma was identified as the cause of this stenosis. This is the first description of a tracheal osteochondroma in a bird.

  16. Manganese Promotion in Titania-Supported Cobalt Fischer-Tropsch Catalysis

    NARCIS (Netherlands)

    Morales Cano, F.

    2006-01-01

    Using the Fischer-Tropsch technology high molecular hydrocarbons are synthesized from CO/H2 mixtures through a surface-catalyzed polymerization reaction using Co-based catalysts. This process enables the transformation of natural gas into clean synthetic fuels. The work discribed in this thesis is t

  17. Modeling of single tube Fischer-Tropsch reactor for model biosyngas

    Energy Technology Data Exchange (ETDEWEB)

    Rafiq, Muhammad Hamid; Hustad, Johan Einar

    2010-07-01

    Fischer-Tropsch Synthesis is an important chemical process for the production of liquid fuels. The present study addresses the modeling of low temperature single tube Fischer- Tropsch reactor for a model biosyngas (33%H2, 17%CO and 50%N2). Cobalt based catalyst is used for synthesis due to its high activity and selectivity for linear hydrocarbons and lower price compared with other noble metals. The chemistry taking place in a FT reactor is complex but can be simplified by the following reaction (see original paper). For cobalt catalyst methanation reaction and shift reaction is neglected. Yates and Satterfield[1] determined the intrinsic rate constant of H2 consumption on a commercial cobalt catalyst. According to Steynberg et al.[2], the intrinsic activity of modern industrial cobalt catalyst is by a factor of three times higher then those reported by the above mentioned author. So, the equation of hydrogen consumption on a commercial cobalt catalyst is estimated (using the threefold value) and is given below: (see original paper). Modeling of Single tube fixed bed Fischer-Tropsch reactor is done with one or two dimensional pseudo homogeneous model. Among many thing the influence of cooling temperature effects are studied on the axial molar composition profiles, molar flow of reactant and product and reactant conversion. In addition effect of cooling temperature on the axial temperature profiles in a single tube Fischer-Tropsch reactor is also studied. (AG)

  18. On the Deactivation of Cobalt-based Fischer-Tropsch Catalysts

    NARCIS (Netherlands)

    Cats, K.H.

    2016-01-01

    The Fischer-Tropsch Synthesis (FTS) process is an attractive way to obtain synthetic liquid fuel from alternative energy sources such as natural gas, coal or biomass. However, the deactivation of the catalyst, consisting of cobalt nanoparticles supported on TiO2, currently hampers the industrial app

  19. Urea as the basic component in pyridine-free Karl Fischer reagent

    NARCIS (Netherlands)

    Bos, M.

    1984-01-01

    A solution of urea, sulphur dioxide and sodium salicylate in methanol is proposed as the solvent in the Karl Fischer titration, with a separate iodine solution as titrant. Comparison of the performance of this solvent with that of some commercial reagents shows that it is has distinct advantages for

  20. Reaction rates between water and some modified rapidly-reacting Karl Fischer reagents.

    Science.gov (United States)

    Cedergren, A

    1978-04-01

    Rate constants were determined for the reaction between water and various modified Karl Fischer reagents containing formamide, dimethylformamide or N-methylformamide. It was shown that the reaction rate can be increased by a factor of 100 by using a reagent containing 40% v/v formamide in pyridine compared to that obtained by use of the conventional methanolic reagent.

  1. A Highly Active and Selective Manganese Oxide Promoted Cobalt-on-Silica Fischer-Tropsch Catalyst

    NARCIS (Netherlands)

    den Breejen, Johan P.; Frey, Anne M.; Yang, Jia; Holmen, Anders; van Schooneveld, Matti M.; de Groot, Frank M. F.; Stephan, Odile; Bitter, Johannes H.; de Jong, Krijn P.

    2011-01-01

    A highly active and selective manganese oxide-promoted silica-supported cobalt catalyst for the Fischer-Tropsch reaction is reported. Co/MnO/SiO2 catalysts were prepared via impregnation of a cobalt nitrate and manganese nitrate precursor, followed by drying and calcination in an NO/He flow. The cat

  2. Structure-performance relationships for supported cobalt Fischer-Tropsch catalysts

    NARCIS (Netherlands)

    Eschemann, T.O.

    2015-01-01

    The Fischer-Tropsch synthesis (FTS) involves the heterogeneously catalyzed conversion of synthesis gas into water and hydrocarbons and offers a promising route for the synthesis of ultraclean fuels, chemicals and lubricants. The synthesis gas can be generated from different feedstocks, such as coal

  3. Cobalt supported on carbon nanofibers as catalysts for the Fischer-Tropsch synthesis

    NARCIS (Netherlands)

    Bezemer, G.L.

    2006-01-01

    The Fischer-Tropsch (FT) process converts synthesis gas (H2/CO) over a heterogeneous catalyst into hydrocarbons. Generally, cobalt catalysts supported on oxidic carriers are used for the FT process, however it appears to be difficult to obtain and maintain fully reduced cobalt particles. To overcome

  4. Memory Matters

    Science.gov (United States)

    ... Emergency Room? What Happens in the Operating Room? Memory Matters KidsHealth > For Kids > Memory Matters A A ... of your complex and multitalented brain. What Is Memory? When an event happens, when you learn something, ...

  5. MEMORY MODULATION

    Science.gov (United States)

    Roozendaal, Benno; McGaugh, James L.

    2011-01-01

    Our memories are not all created equally strong: Some experiences are well remembered while others are remembered poorly, if at all. Research on memory modulation investigates the neurobiological processes and systems that contribute to such differences in the strength of our memories. Extensive evidence from both animal and human research indicates that emotionally significant experiences activate hormonal and brain systems that regulate the consolidation of newly acquired memories. These effects are integrated through noradrenergic activation of the basolateral amygdala which regulates memory consolidation via interactions with many other brain regions involved in consolidating memories of recent experiences. Modulatory systems not only influence neurobiological processes underlying the consolidation of new information, but also affect other mnemonic processes, including memory extinction, memory recall and working memory. In contrast to their enhancing effects on consolidation, adrenal stress hormones impair memory retrieval and working memory. Such effects, as with memory consolidation, require noradrenergic activation of the basolateral amygdala and interactions with other brain regions. PMID:22122145

  6. Study of (Fe/HZM-5) catalyst be used in the Fischer-Tropsch synthesis: preparation and characterization; Estudo do catalisador (Fe/HZSM-5) a ser utilizado na sintese de Fischer-Tropsch: preparacao e caracterizacao

    Energy Technology Data Exchange (ETDEWEB)

    Gonzaga, Arthur C. [Universidade Estadual do Maranhao (UEMA0), MA (Brazil); Sousa, Bianca V. de; Lima, Wellington S.; Rodrigues, Meiry G.F. [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia Quimica

    2008-07-01

    In this work it was developed an iron catalyst supported on the ZSM-5 zeolite to be used in the Fischer-Tropsch Synthesis (FTS). The NH{sub 4}{sup +}ZSM-5 zeolitic support was submitted to the wet impregnation, using the 0.1 M of the Fe(NO{sub 3}){sub 3}.9H{sub 2}O solution to obtain the Fe/NH{sub 4}{sup +}ZSM-5 sample in the content of iron 5% wt. After, the material was submitted for the drying process and in the following, for the calcination one, obtaining the Fe/HZSM-5 form. The EDS characterization analyses showed that in the Fe/HZSM-5 sample the iron is in the Fe{sub 2}O{sub 3} form and that the impregnation and calcination processes did not cause significant exchanges in the zeolitic support framework. The results of the N{sub 2} physical adsorption of the 5% Fe/HZSM-5 showed the presence of the micropores and mesopores. From these results, the obtained material (5% Fe/HZSM-5) presents a great potential to be used like a catalyst in the FTS. (author)

  7. Great Lakes Science Center

    Data.gov (United States)

    Federal Laboratory Consortium — Since 1927, Great Lakes Science Center (GLSC) research has provided critical information for the sound management of Great Lakes fish populations and other important...

  8. Protective effects of glutathione on bromodichloromethane in vivo toxicity and in vitro macromolecular binding in Fischer 344 rats.

    Science.gov (United States)

    Gao, P; Thornton-Manning, J R; Pegram, R A

    1996-10-11

    Bromodichloromethane (BDCM), a carcinogenic water disinfection by-product, has been shown to be metabolized to intermediates that covalently bind to lipids and proteins, and this binding has been associated with trihalomethane-induced renal and hepatic toxicity. In this study, the effects of glutathione (GSH) on in vivo BDCM toxicity and in vitro BDCM macromolecular binding were evaluated. The in vivo toxicity of BDCM in animals pretreated with buthionine sulfoximine (BSO, a glutathione synthesis inhibitor) and in untreated male Fischer 344 rats was investigated. In another experiment, covalent binding to protein and lipid was quantified after [14C]BDCM was incubated with hepatic microsomal and S9 fractions and renal microsomes from F344 rats, under aerobic and anaerobic conditions, with and without added GSH. After oral dosing with BDCM, the BSO-pretreated animals had greatly increased levels of serum indicators of hepatotoxicity and serum and urinary indicators of nephrotoxicity compared to those in animals dosed solely with BDCM. Histopathological examination revealed that hepatic necrosis was more severe than renal necrosis in the BSO-treated rats. When GSH was added to an aerobic incubation, protein binding was decreased in hepatic microsomal and S9 fractions by 92 and 83%, respectively. GSH also decreased lipid binding by 55% in hepatic microsomal incubations carried out under anaerobic conditions. Addition of GSH decreased renal microsomal protein (aerobic) and lipid binding (anaerobic) by 20 and 43%, respectively. These data indicate that GSH is an important protective factor in the toxicity associated with BDCM.

  9. Influence of lanthanum on the performance of Zr-Co/activated carbon catalysts in Fischer-Tropsch synthesis

    Institute of Scientific and Technical Information of China (English)

    Tao Wang; Yunjie Ding; Yuan Lü; Hejun Zhu; Liwu Lin

    2008-01-01

    The influence of La loading on Zr-Co/activated carbon (AC) catalysts has been studied for Fischer-Tropsch syn-thesis. The catalyst samples were characterized by XRD, TPR, CO-TPD, and temperature programmed CO hydrogenation.The catalytic property was evaluated in a fixed bed reactor. The experimental results showed that CO conversion increased from 86.4% to 92.3% and the selectivity to methane decreased from 14.2% to 11.5% and C5+ selectivity increased from 71.0% to 74.7% when low La loading (La=0.2wt%) was added into the Zr-Co/AC catalyst. However, high loadings of La (La= 0.3-1.0 wt%) would decrease catalyst activity as well as the C5+ selectivity and increase methane selectivity. XRD results displayed that La-modified Zr-Co/AC catalyst had little effect on the dispersion of Co catalyst. But, the results of TPR, CO-TPD, and temperature programmed CO hydrogenation techniques indicated that the extent of cobalt reduction was found to greatly influence the activity and selectivity of the catalyst. The addition of a small amount of La increased the reducibility of the Zr-Co/AC catalyst and restrained the formation of methane and improved the selectivity to long chain hydrocarbons. However, excess of La led to the decrease of the reducibility of Co catalyst thus resulted in higher methanation activity.

  10. CHAIN-LIMITING OPERATION OF FISCHER-TROPSCH REACTOR

    Energy Technology Data Exchange (ETDEWEB)

    Apostolos A. Nikolopoulos; Santosh K. Gangwal

    2003-06-01

    The use of pulsing in Fischer-Tropsch (FT) synthesis to limit the hydrocarbon chain growth and maximize the yield of diesel-range (C{sub 10}-C{sub 20}) products was examined on high-chain-growth-probability ({alpha} {ge} 0.9) FT catalysts. Pulsing experiments were conducted using a stainless-steel fixed-bed micro-reactor, equipped with both on-line (for the permanent gases and light hydrocarbons, C{sub 1}-C{sub 15}) and off-line (for the heavier hydrocarbons, C{sub 10}-C{sub 65}) gas chromatography analysis. Additional experiments were performed using a highly active attrition-resistant iron-based FT synthesis catalyst in a 1-liter continuous stirred-tank rector (CSTR). On both a Co-ZrO{sub 2}/SiO{sub 2} and a Co/Al{sub 2}O{sub 3} FT synthesis catalyst application of H{sub 2} pulsing causes significant increase in CO conversion, and only an instantaneous increase in undesirable selectivity to CH{sub 4}. Increasing the frequency of H{sub 2} pulsing enhances the selectivity to C{sub 10}-C{sub 20} compounds but the chain-growth probability {alpha} remains essentially unaffected. Increasing the duration of H{sub 2} pulsing results in enhancing the maximum obtained CO conversion and an instantaneous selectivity to CH{sub 4}. An optimum set of H{sub 2} pulse parameters (pulse frequency, pulse duration) is required for maximizing the yield of desirable diesel-range C{sub 10}-C{sub 20} products. Application of a suitable H{sub 2} pulse in the presence of added steam in the feed is a simple method to overcome the loss in activity and the shift in paraffin vs. olefin selectivity (increase in the olefin/paraffin ratio) caused by the excess steam. A decrease in syngas concentration has a strong suppressing effect on the olefin/paraffin ratio of the light hydrocarbon products. Higher syngas concentration can increase the chain growth probability {alpha} and thus allow for better evaluation of the effect of pulsing on FT synthesis. On a high-{alpha} Fe/K/Cu/SiO{sub 2} FT

  11. Kinetics of Slurry Phase Fischer-Tropsch Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Dragomir B. Bukur; Gilbert F. Froment; Tomasz Olewski; Lech Nowicki; Madhav Nayapati

    2006-12-31

    The overall objective of this project is to develop a comprehensive kinetic model for slurry-phase Fischer-Tropsch synthesis (FTS) employing iron-based catalysts. This model will be validated with experimental data obtained in a stirred-tank slurry reactor (STSR) over a wide range of process conditions. Three STSR tests of the Ruhrchemie LP 33/81 catalyst were conducted to collect data on catalyst activity and selectivity under 25 different sets of process conditions. The observed decrease in 1-olefin content and increase in 2-olefin and n-paraffin contents with the increase in conversion are consistent with a concept that 1-olefins participate in secondary reactions (e.g. 1-olefin hydrogenation, isomerization and readsorption), whereas 2-olefins and n-paraffins are formed in these reactions. Carbon number product distribution showed an increase in chain growth probability with increase in chain length. Vapor-liquid equilibrium calculations were made to check validity of the assumption that the gas and liquid phases are in equilibrium during FTS in the STSR. Calculated vapor phase compositions were in excellent agreement with experimental values from the STSR under reaction conditions. Discrepancies between the calculated and experimental values for the liquid-phase composition (for some of the experimental data) are ascribed to experimental errors in the amount of wax collected from the reactor, and the relative amounts of hydrocarbon wax and Durasyn 164 oil (start-up fluid) in the liquid samples. Kinetic parameters of four kinetic models (Lox and Froment, 1993b; Yang et al., 2003; Van der Laan and Beenackers, 1998, 1999; and an extended kinetic model of Van der Laan and Beenackers) were estimated from experimental data in the STSR tests. Two of these kinetic models (Lox and Froment, 1993b; Yang et al., 2003) can predict a complete product distribution (inorganic species and hydrocarbons), whereas the kinetic model of Van der Laan and Beenackers (1998, 1999) can

  12. Saksa välisminister : kirjutage, et Joschka Fischer on süüdi / Heiki Suurkask

    Index Scriptorium Estoniae

    Suurkask, Heiki, 1972-

    2005-01-01

    Saksa välisminister Joschka Fischer tunnistas oma poliitilist vastutust selle eest, et Saksamaa viisaga oli võimalik illegaalseid immigrante Saksamaale tuua, samas süüdistas ta opositsiooni skandaali ülespuhumises

  13. Effect of potassium promoter on cobalt nano-catalysts for fischer-tropsch reaction

    Science.gov (United States)

    Ali, Sardar; Mohd Zabidi, Noor Asmawati; Subbarao, Duvvuri

    2012-09-01

    In the present work effect of potassium on cobalt nano-catalysts for Fischer-Tropsch reaction has been presented. The catalysts were prepared using a wet impregnation method and promoted with potassium. Samples were characterized by nitrogen adsorption, H2-TPR, and TEM. The Fischer-Tropsch Synthesis (FTS) was carried out in a fixed-bed microreactor 220 δC, 1 atm, H2/CO = 2 and a velocity (SV) =12 L/g.h. for 5 h. Addition of potassium into Co/CNTs decreased the average size of cobalt nanoparticles and the catalyst reducibility. Potassium-promoted Co catalyst resulted in appreciable increase in the selectivity of C5+ hydrocarbons and suppressed methane formation. The 0.06%KCo/CNTs catalyst enhanced the C5+ hydrocarbons selectivity by a factor of 23.5% and reduced the methane selectivity by a factor of 39.6%

  14. Modeling of a slurry bubble column reactor for Fischer-Tropsch synthesis

    Institute of Scientific and Technical Information of China (English)

    QIAN Wei-xin; MA Hong-fang; LI Tao; YING Wei-yong; FANG Ding-ye

    2012-01-01

    On the basis of the global CO consumption rate model,the lumped product distribution model and the sedimentation-dispersion model of a catalyst,a steady-state,one-dimensional mathematical model of the slurry bubble column reactor for Fischer-Tropsch synthesis were established.The mathematical simulation of the slurry bubble column reactor for Fischer-Tropsch synthesis was carried out under the following typical industrial operating conditions:temperature 230 ℃,pressure 3.0 MPa,gas flow 5× 105 m3/h,catalyst content in slurry phase 30%,reactor diameter 5.0 m and the composition of feed gas:y(H2)=0.60,y(CO)=0.30,y(N2)=0.10.The influences of operating pressure,temperature and m(H2)/m(CO) in feed gas on the reactor's reaction performance were simulated.

  15. Nitrogen isotope fractionations in the Fischer-Tropsch synthesis and in the Miller-Urey reaction

    Science.gov (United States)

    King, C.-C.; Clayton, R. N.; Hayatsu, R.; Studier, M. H.

    1979-01-01

    Nitrogen isotope fractionations have been measured in Fischer-Tropsch and Miller-Urey reactions in order to determine whether these processes can account for the large N-15/N-14 ratios found in organic matter in carbonaceous chondrites. Polymeric material formed in the Fischer-Tropsch reaction was enriched in N-15 by only 3 per mil relative to the starting material (NH3). The N-15 enrichment in polymers from the Miller-Urey reaction was 10-12 per mil. Both of these fractionations are small compared to the 80-90 per mil differences observed between enstatite chondrites and carbonaceous chondrites. These large differences are apparently due to temporal or spatial variations in the isotopic composition of nitrogen in the solar nebula, rather than to fractionation during the production of organic compounds.

  16. Design of generic coal conversion facilities: Indirect coal liquefaction, Fischer-Tropsch synthesis

    Energy Technology Data Exchange (ETDEWEB)

    1991-10-01

    A comprehensive review of Fischer-Tropsch (F-T) technology, including fixed, fluidized, and bubble column reactors, was undertaken in order to develop an information base before initiating the design of the Fischer-Tropsch indirect liquefaction PDU as a part of the Generic Coal Conversion Facilities to be built at the Pittsburgh Energy Technology Center (PETC). The pilot plant will include a fixed bed and slurry bubble column reactor for the F-T mode of operation. The review encompasses current status of both these technologies, their key variables, catalyst development, future directions, and potential improvement areas. However, more emphasis has been placed on the slurry bubble column reactor since this route is likely to be the preferred technology for commercialization, offering process advantages and, therefore, better economics than fixed and fluidized bed approaches.

  17. Fischer-Tropsch diesel production over calcium-promoted Co/alumina catalyst: Effect of reaction conditions

    Energy Technology Data Exchange (ETDEWEB)

    A.R. de la Osa; A. De Lucas; A. Romero; J.L. Valverde; P. Sanchez [University of Castilla-La Mancha, Ciudad Real (Spain). Chemical Engineering Department

    2011-05-15

    The effects of reaction conditions on the Fischer-Tropsch activity and product distribution of an alkali-earth metal promoted cobalt based catalyst were studied. The influence of the promoter on the reducibility and cobalt particle size was studied by different techniques, including N{sub 2} adsorption, X-ray diffraction, temperature-programmed reduction, temperature-programmed desorption and acid-base titrations. Experiments were carried out on a bench-scale fixed bed reactor and catalysts were prepared by incipient wetness impregnation. It was observed that addition of a small amount of calcium oxide as a promoter (0.6 wt.%) improved the cobalt oxide reducibility and reduced the formation of cobalt-aluminate species. A positive correlation between basicity and particle size was observed. In terms of FTS results, CO conversion and C{sub 5}{sup +} selectivity were found to be enhanced by the addition of this promoter. It was important to note that the addition of calcium shifted the distribution to mainly C{sub 16}-C{sub 18} hydrocarbons fraction, which could be greatly considered for a diesel formulation. Furthermore, the variation of the reaction conditions seemed to influence product distribution in a lesser extent than unpromoted catalyst. Also, a displacement of hydrocarbon distribution to higher molecular weight with decreasing space velocity and temperature was observed. Moreover, the addition of calcium to the cobalt based catalyst was found to greatly maintain selectivity to C{sub 5}{sup +} for a wide range of H{sub 2}/CO molar ratios. 60 refs., 10 figs., 5 tabs.

  18. Absorption and disposition kinetics of 3,3',4,4'-tetrachloroazoxybenzene in the male Fischer 344 rat.

    Science.gov (United States)

    Ziegler, T L; Pillai, U A; Smith, R L; Kattnig, M J; Liebler, D C; Mayersohn, M; Sipes, I G

    1996-09-01

    3,3',4,4'-Tetrachloroazoxybenzene (TCAOB) is a structural analog of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). It is formed as a byproduct during the synthesis of industrial products such as herbicides. TCAOB is a ligand for the Ah receptor and, at much higher doses, exhibits toxicities similar to TCDD. Although the reduced in vivo toxicity of TCAOB probably reflects differences in disposition, this study characterized its absorption and disposition kinetics. Male Fischer 344 rats were administered [14C]TCAOB (3.4 or 34 mg/kg p.o., 3.4 mg/kg i.v.), and the excretion of the radiolabel was monitored over 96 hr. After the low and high dose, 35% and 30% of the [14C]TCAOB were eliminated in the urine, with 55% and 54% eliminated in the feces. At 96 hr, the adipose tissue:blood ratios of [14C]TCAOB equivalents were 8 and 26 for the low and high doses, respectively. After the intravenous dose of TCAOB, the adipose tissue:blood ratio was 21 at 96 hr. Other tissue:blood ratios were of little significance (0.06-3.2). Pharmacokinetic parameters indicate that the parent molecule is cleared from blood with an average half-life of 7 hr and an average clearance of 11 ml/min.kg. Absolute bioavailability was calculated to be approximately 9%. Urine contained a variety of dichlorolaniline conjugates, which support the importance of azo reduction in the disposition of TCAOB. When compared with TCDD, the absorption of TCAOB is greatly reduced and the elimination of metabolites greatly enhanced. Therefore, at equal molar oral doses, TCAOB would express lower levels of Ah receptor-mediated toxicity than those defined for TCDD.

  19. X-ray nanoscopy of cobalt Fischer-Tropsch catalysts at work.

    Science.gov (United States)

    Cats, Korneel H; Gonzalez-Jimenez, Ines D; Liu, Yijin; Nelson, Johanna; van Campen, Douglas; Meirer, Florian; van der Eerden, Ad M J; de Groot, Frank M F; Andrews, Joy C; Weckhuysen, Bert M

    2013-05-21

    Transmission X-ray microscopy has been used to investigate individual Co/TiO2 Fischer-Tropsch (FT) catalyst particles in 2-D and 3-D with 30 nm spatial resolution. Tomographic elemental mapping showed that Co is heterogeneously concentrated in the centre of the catalyst particles. In addition, it was found that Co is mostly metallic during FT at 250 °C and 10 bar. No evidence for Co oxidation was found.

  20. Modification of Karl Fischer Method for Determination of Water in light Petroleum Products Including Aviation Fuels

    Directory of Open Access Journals (Sweden)

    R. C. Misra

    1971-04-01

    Full Text Available Classical Karl Fischer method has been modified so as to make it suitable for determining free and dissolved water present in aviation fuels in excess of 10 ppm which is considered as limiting concentration value for safe fueling of aircrafts particularly in the arduous climatic conditions as encountered in military operations. The modified method employed a special ethylene glyccl solvent mixture and another water saturated fuel sample as blank.

  1. Fischer-Tropsch synthesis and the generation of DME in situ

    Energy Technology Data Exchange (ETDEWEB)

    Zonetti, Priscila C.; Gaspar, Alexandre B.; Appel, Lucia G. [Divisao de Catalise e Processos Quimicos, Instituto Nacional de Tecnologia, Av. Venezuela 82/518, CEP 21081-312, Rio de Janeiro, RJ (Brazil); Mendes, Fabiana M.T. [Divisao de Metrologia de Materiais (DIMAT), Instituto Nacional de Metrologia, Normatizacao e Qualidade Industrial, INMETRO, Av. Nossa Senhora das Gracas 50, CEP 25250-020, Xerem, Duque de Caxias, RJ (Brazil); Sobrinho, Eledir V.; Sousa-Aguiar, Eduardo F. [CENPES/Petrobras, Ilha do Fundao, quadra 7, Cidade Universitaria, 21949-900, Rio de Janeiro (Brazil)

    2010-05-15

    Ternary physical mixtures comprised a Fischer-Tropsch catalyst, a methanol synthesis catalyst and a zeolite employed in the hydrocarbon synthesis from syngas. Two Fe-based catalysts (i.e., one promoted by K and the other by Ru), two HY zeolites with different acidities, a commercial HZSM-5 and Cu/ZnO/Al{sub 2}O{sub 3} (methanol synthesis catalyst) were used in these systems. The main products obtained were dimethyl ether, methanol and hydrocarbons. First of all, it was observed that by adding Cu/ZnO/Al{sub 2}O{sub 3} catalyst to a binary physical mixture comprised of a Fischer-Tropsch catalyst and HZSM-5, the CO conversion increases more than 20 times. Second, during the reaction transient period the dimethyl ether selectivity decreases as the conversion increases. Third, the hydrocarbons synthesized followed the ASF distribution in the C{sub 1}-C{sub 12} range and finally, it was also verified that the Y zeolites and the Fischer-Tropsch synthesis catalyst promoted by Ru generated the most active physical mixtures. The results showed that the role of zeolites in the ternary physical mixture is only associated with the dimethyl ether synthesis. The following reaction pathway was suggested: first, methanol is synthesized from syngas using Cu/ZnO/Al{sub 2}O{sub 3} catalyst; after that, this alcohol is dehydrated by an acid catalyst generating DME; and lastly, DME initiates Fischer-Tropsch synthesis, which is then propagated by CO. (author)

  2. Visualization of the relationship between Fischer and Haworth projections of monosaccharides by animation on a microcomputer.

    Science.gov (United States)

    Ewart, J F; Kirby, G H; Rayner, J D

    1994-06-01

    An animation is described to assist in the visualization of the relationship between the Fischer and Haworth projections of monosaccharides. The animation helps the understanding of two quite different, commonly used representations of the same molecule. The animation runs on a 386-based PC with VGA graphics. The method for realizing such an animation on this hardware is described in detail; C code is provided in the Appendix.

  3. Nano-sized cobalt based Fischer-Tropsch catalysts for gas-to-liquid process applications.

    Science.gov (United States)

    Kang, Jung Shik; Awate, S V; Lee, Yun Ju; Kim, So Jung; Park, Moon Ju; Lee, Sang Deuk; Hong, Suk-In; Moon, Dong Ju

    2010-05-01

    Nano-sized cobalt supported catalysts were prepared for Fischer-Tropsch synthesis in gas-to-liquid (GTL) process. The dependence of crystallite size and reducibility of Co3O4 on the supports were investigated with FTS activity. XRD peaks revealed nano crystallites ( Co/Al2O3 (70.0%) > Co/R_TiO2 (61%) > Co/A_TiO2 (57.5%).

  4. EL FENÓMENO DE LA MEMORIA ELÉCTRICA: UN GRAN SIMULADOR. PRESENTACIÓN DE DOS CASOS / Electrical memory phenomenon - a great deceiver. Presentation of two cases

    Directory of Open Access Journals (Sweden)

    Raimundo Carmona Puerta

    2010-09-01

    Full Text Available Resumen Presentamos dos pacientes en los que se desarrollaron ondas T negativas que aparecen en el electrocardiograma por la memoria eléctrica cardíaca. Este fenómeno aunque fue descrito hace muchos años es causa de interpretación errónea de ondas T debido a isquemia cardíaca, y puede ser visto en ciertas situaciones clínicas que permiten sospechar su presencia. / Abstract We present two patients in whom negative T waves are developed, and appeared in the electrocardiogram as a result of the electric cardiac memory. Though described many years ago, this phenomenon is the cause for t-wave misinterpretation due to cardiac ischemia. It can be seen in certain clinical situations which lead to suspect its presence.

  5. Computational chemistry insights in the REDOX Behaviour of Cr and W Fischer carbene complexes

    Science.gov (United States)

    Landman, Marile; Conradie, Jeanet; van Rooyen, Petrus H.

    2015-09-01

    An electrochemical study of a series of Fischer carbene complexes containing a hetero-aryl group showed that Cr and W carbenes exhibit different electrochemical behaviour. The Cr carbenes are oxidized in two one electron oxidation processes, namely Cr(0) to Cr(I) and Cr(I) to Cr(II). On the contrary, Fischer carbene complexes of tungsten are directly oxidized from W(0) to W(II). The first reduction process observed for both W- and Cr- carbenes, is a one electron process. A density functional theory (DFT) computational chemistry study of the electronic structure of the Cr- and W-carbenes, showed that the oxidation is metal based and the reduction is located on the carbene ligand. The DFT calculations further showed that the Cr(II) species is a triplet and the W(II) species a closed shell singlet. The DFT calculated energies of the HOMO and LUMO of the neutral carbenes relate linearly to the experimental oxidation and reduction potential, respectively. These mathematical relationships obtained can be used to predict experimentally measured potentials of related Fischer carbene complexes.

  6. Synthesis in situ of gold nanoparticles by a dialkynyl Fischer carbene complex anchored to glass surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Bertolino, María Candelaria, E-mail: cbertolino@fcq.unc.edu.ar; Granados, Alejandro Manuel, E-mail: ale@fcq.unc.edu.ar

    2016-10-15

    Highlights: • Fischer carbene 1-W reacts via cycloaddition without Cu(I) with azide terminal surface. • This reaction on the surface is regioselective to internal triple bond of 1-W. • 1-W bound to glass surface produce AuNps in situ fixed to the surface. • This ability is independent of how 1-W is bonded to the surface. • This hybrid surface can be valuable as SERS substrate or in heterogeneous catalysis. - Abstract: In this work we present a detailed study of classic reactions such as “click reaction” and nucleophilic substitution reaction but on glass solid surface (slides). We used different reactive center of a dialkynylalcoxy Fischer carbene complex of tungsten(0) to be anchored to modified glass surface with amine, to obtain aminocarbene, and azide terminal groups. These cycloaddition reaction showed regioselectivity to internal triple bond of dialkynyl Fischer carbene complex without Cu(I) as catalyst. Anyway the carbene anchored was able to act as a reducing agent to produce in situ very stable gold nanoparticles fixed on surface. We showed the characterization of modified glasses by contact angle measurements and XPS. Synthesized nanoparticles were characterized by SEM, XPS, EDS and UV–vis. The modified glasses showed an important enhancement Raman-SERS. This simple, fast and robust method to create a polifunctional and hybrid surfaces can be valuable in a wide range of applications such as Raman-SERS substrates and other optical fields.

  7. Size dependent stability of cobalt nanoparticles on silica under high conversion Fischer-Tropsch environment.

    Science.gov (United States)

    Wolf, Moritz; Kotzé, Hendrik; Fischer, Nico; Claeys, Michael

    2017-02-15

    Highly monodisperse cobalt crystallites, supported on Stöber silica spheres, as model catalysts for the Fischer-Tropsch synthesis were exposed to simulated high conversion environments in the presence and absence of CO utilising an in house developed in situ magnetometer. The catalyst comprising the smallest crystallites in the metallic state (average diameter of 3.2 nm) experienced pronounced oxidation whilst the ratio of H2O to H2 was increased stepwise to simulate CO conversions from 26% up to complete conversion. Direct exposure of this freshly reduced catalyst to a high conversion Fischer-Tropsch environment resulted in almost spontaneous oxidation of 40% of the metallic cobalt. In contrast, a model catalyst with cobalt crystallites of 5.3 nm only oxidised to a small extent even when exposed to a simulated conversion of over 99%. The largest cobalt crystallites were rather stable and only experienced measurable oxidation when subjected to H2O in the absence of H2. This size dependency of the stability is in qualitative accordance with reported thermodynamic calculations. However, the cobalt crystallites showed an unexpected low susceptibility to oxidation, i.e. only relatively high ratios of H2O to H2 partial pressure caused oxidation. Similar experiments in the presence of CO revealed the significance of the actual Fischer-Tropsch synthesis on the metallic surface as the dissociation of CO, an elementary step in the Fischer-Tropsch mechanism, was shown to be a prerequisite for oxidation. Direct oxidation of cobalt to CoO by H2O seems to be kinetically hindered. Thus, H2O may only be capable of indirect oxidation, i.e. high concentrations prevent the removal of adsorbed oxygen species on the cobalt surface leading to oxidation. However, a spontaneous direct oxidation of cobalt at the interface between the support and the crystallites by H2O forming presumably cobalt silicate type species was observed in the presence and absence of CO. The formation of these

  8. High IFN-α expression is associated with the induction of experimental autoimmune uveitis (EAU) in Fischer 344 rat

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Thl-response plays a crucial role in determining pathogenesis of organ-specific autoimmune diseases. It is believed that both IL-12 and INF-α are initiators to regulate Th1- response. In our experimental autoimmune uveitis (EAU) model, both Lewis and Fischer 344 rats share the same MHC class ⅡI molecules,while Lewis rat is EAU susceptible and Fischer 344 rat is EAU resistant. However, under the same condition of immunization, if pertussis toxin (PTX) was injected intraperitoneally as an additional adjuvant, Fischer 344 rat can develop EAU. In this study we investigate which mechanisms are involved in the induction of EAU in CFA+R16+PTX-treated (CRP-treated) Fischer 344 rats. In vivo and in vitro data demonstrated that Thl-cytokine, IFN-γ mRNA expression was significantly increased in disease target tissue-eyes and in draining lymph node cells of CRP-treated Fischer 344 rat. When IL-12 and IFN-α mRNA expression were compared in the experimental groups, only IFN-α mRNA expression was associated with EAU development.To distinguish the sources of IFN-α producing cells, it was observed that IFN-α expression was mainly produced by macrophages. It was further confirmed that normal macrophage from Fischer 344 rat was able to produce significant IFN-α in the presence of PTX. The data strongly suggested that IFN-α might be involved in initiating Thl-cell differentiation and in turn contribute to the induction of EAU. High IFN-αexpression induced by PTX may represent a novel pathway to initiate Thl response in Fischer 344 rat.

  9. Atlas of Great Comets

    Science.gov (United States)

    Stoyan, Ronald; Dunlop, Storm

    2015-01-01

    Foreword; Using this book; Part I. Introduction: Cometary beliefs and fears; Comets in art; Comets in literature and poetry; Comets in science; Cometary science today; Great comets in antiquity; Great comets of the Middle Ages; Part II. The 30 Greatest Comets of Modern Times: The Great Comet of 1471; Comet Halley 1531; The Great Comet of 1556; The Great Comet of 1577; Comet Halley, 1607; The Great Comet of 1618; The Great Comet of 1664; Comet Kirch, 1680; Comet Halley, 1682; The Great Comet of 1744; Comet Halley, 1759; Comet Messier, 1769; Comet Flaugergues, 1811; Comet Halley, 1835; The Great March Comet of 1843; Comet Donati, 1858; Comet Tebbutt, 1861; The Great September Comet of 1882; The Great January Comet of 1910; Comet Halley, 1910; Comet Arend-Roland, 1956; Comet Ikeya-Seki, 1965; Comet Bennett, 1970; Comet Kohoutek, 1973-4; Comet West, 1976; Comet Halley, 1986; Comet Shoemaker-Levy 9, 1994; Comet Hyakutake, 1996; Comet Hale-Bopp, 1997; Comet McNaught, 2007; Part III. Appendices; Table of comet data; Glossary; References; Photo credits; Index.

  10. Shape memory polymer foams

    Science.gov (United States)

    Santo, Loredana

    2016-02-01

    Recent advances in shape memory polymer (SMP) foam research are reviewed. The SMPs belong to a new class of smart polymers which can have interesting applications in microelectromechanical systems, actuators and biomedical devices. They can respond to specific external stimulus changing their configuration and then remember the original shape. In the form of foams, the shape memory behaviour can be enhanced because they generally have higher compressibility. Considering also the low weight, and recovery force, the SMP foams are expected to have great potential applications primarily in aerospace. This review highlights the recent progress in characterization, evaluation, and proposed applications of SMP foams mainly for aerospace applications.

  11. Memory Modulation

    NARCIS (Netherlands)

    Roozendaal, Benno; McGaugh, James L.

    2011-01-01

    Our memories are not all created equally strong: Some experiences are well remembered while others are remembered poorly, if at all. Research on memory modulation investigates the neurobiological processes and systems that contribute to such differences in the strength of our memories. Extensive evi

  12. Memory Matters

    Science.gov (United States)

    ... the brain that actually make memories harder to recall. previous continue Signs of a Memory Problem A person might — or might not — be ... A doctor will test the person's ability to recall events, names, or places by ... . If the person has memory loss from a head injury, the doctor will ...

  13. Cancer immunotherapy and immunological memory.

    Science.gov (United States)

    Murata, Kenji; Tsukahara, Tomohide; Torigoe, Toshihiko

    2016-01-01

      Human immunological memory is the key distinguishing hallmark of the adaptive immune system and plays an important role in the prevention of morbidity and the severity of infection. The differentiation system of T cell memory has been clarified using mouse models. However, the human T cell memory system has great diversity induced by natural antigens derived from many pathogens and tumor cells throughout life, and profoundly differs from the mouse memory system constructed using artificial antigens and transgenic T cells. We believe that only human studies can elucidate the human immune system. The importance of immunological memory in cancer immunotherapy has been pointed out, and the trafficking properties and long-lasting anti-tumor capacity of memory T cells play a crucial role in the control of malignant tumors. Adoptive cell transfer of less differentiated T cells has consistently demonstrated superior anti-tumor capacity relative to more differentiated T cells. Therefore, a human T cell population with the characteristics of stem cell memory is thought to be attractive for peptide vaccination and adoptive cell transfer. A novel human memory T cell population that we have identified is closer to the naive state than previous memory T cells in the T cell differentiation lineage, and has the characteristics of stem-like chemoresistance. Here we introduce this novel population and describe the fundamentals of immunological memory in cancer immunotherapy.

  14. Memory boosting effect of Citrus limon, Pomegranate and their combinations

    National Research Council Canada - National Science Library

    Riaz, Azra; Khan, Rafeeq Alam; Algahtani, Hussein A

    2014-01-01

    Memory is greatly influenced by factors like food, stress and quality of sleep, hence present study was designed to evaluate the effect of Citrus limon and Pomegranate juices on memory of mice using...

  15. Salam Memorial

    CERN Document Server

    Rubbia, Carlo

    1997-01-01

    by T.W.B. KIBBLE / Blackett Laboratory, Imperial College, London. Recollections of Abdus Salam at Imperial College I shall give a personal account of Professor Salam's life and work from the perspective of a colleague at Imperial College, concentrating particularly but not exclusively on the period leading up to the discovery of the electro-weak theory. If necessary I could perhaps give more detail, but only once I have given more thought to what ground I shall cover. by Sheldon Lee GLASHOW / Harvard University, Cambridge, MA, USA. Memories of Abdus Salam. My interactions with Abdus Salam, weak as they have been, extended over five decades. I regret that we never once collaborated in print or by correspondence. I visited Abdus only twice in London and twice again in Trieste, and met him at the occasional conference or summer school. Our face-to-face encounters could be counted on one's fingers and toes, but we became the best of friends. Others will discuss Abdus as an inspiring teacher, as a great scientist,...

  16. Memory protection

    Science.gov (United States)

    Denning, Peter J.

    1988-01-01

    Accidental overwriting of files or of memory regions belonging to other programs, browsing of personal files by superusers, Trojan horses, and viruses are examples of breakdowns in workstations and personal computers that would be significantly reduced by memory protection. Memory protection is the capability of an operating system and supporting hardware to delimit segments of memory, to control whether segments can be read from or written into, and to confine accesses of a program to its segments alone. The absence of memory protection in many operating systems today is the result of a bias toward a narrow definition of performance as maximum instruction-execution rate. A broader definition, including the time to get the job done, makes clear that cost of recovery from memory interference errors reduces expected performance. The mechanisms of memory protection are well understood, powerful, efficient, and elegant. They add to performance in the broad sense without reducing instruction execution rate.

  17. Matter and memory

    CERN Document Server

    Bergson, Henri

    1991-01-01

    Since the end of the last century," Walter Benjamin wrote, "philosophy has made a series of attempts to lay hold of the 'true' experience as opposed to the kind that manifests itself in the standardized, denatured life of the civilized masses. It is customary to classify these efforts under the heading of a philosophy of life. Towering above this literature is Henri Bergson's early monumental work, Matter and Memory."Along with Husserl's Ideas and Heidegger's Being and Time, Bergson's work represents one of the great twentieth-century investigations into perception and memory, movement and time, matter and mind. Arguably Bergson's most significant book, Matter and Memory is essential to an understanding of his philosophy and its legacy.This new edition includes an annotated bibliography prepared by Bruno Paradis.Henri Bergson (1859-1941) was awarded the Nobel Prize in 1927. His works include Time and Free Will, An Introduction to Metaphysics, Creative Evolution, and The Creative Mind.

  18. Great attractor really a great wall

    Energy Technology Data Exchange (ETDEWEB)

    Stebbins, A.; Turner, M.S.

    1988-11-01

    Some of the cosmological consequences are discussed of a late time phase transition which produces light domain walls. The observed peculiar velocity field of the Universe and the observed isotropy of the microwave background radiation severely constrain the wall surface density in such a scenario. The most interesting consequence of such a phase transition is the possibility that the local, coherent streaming motion reported by the Seven Samurai could be explained by the repulsive effect of a relic domain wall with the Hubble volume (the Great Wall).

  19. Great Lakes Teacher's Guide.

    Science.gov (United States)

    Reid, Ron

    The Great Lakes are one of the world's greatest reservoirs of fresh water, the foundation of Ontario's economic development, a primary force in ecological systems, and a base for pleasure and recreation. They are also a magnificent resource for the teachers of Ontario. Study of the Great Lakes can bring to life the factors that shape the ecology…

  20. Great Principles of Computing

    OpenAIRE

    Denning, Peter J.

    2008-01-01

    The Great Principles of Computing is a framework for understanding computing as a field of science. The website ...April 2008 (Rev. 8/31/08) The Great Principles of Computing is a framework for understanding computing as a field of science.

  1. Synthèse de Fischer Tropsch sur support conducteur à base de carbure de silicium

    OpenAIRE

    Tymowski, Benoît de

    2012-01-01

    The Fischer-Tropsch synthesis (FTS) allows the transformation of a mixture of synthesis gas, i.e. H2 and CO, into valuable liquid hydrocarbons. The catalysts generally used in FTS are based on iron or cobalt supported on alumina or silica. ln the present work, silicon carbide (SiC) has been proposed as a replacement media to traditional supports. The results obtained indicate that the mesoporous SiC containing cobalt catalyst exhibits a good FTS activity and an extremely high selectivity towa...

  2. A "cousin" of a theorem of Cs\\'aki and Fischer

    OpenAIRE

    Bradley, Richard C.

    2016-01-01

    A 1963 theorem of P. Cs\\'aki and J. Fischer deals with the "maximal correlation coefficient" in the context of independent pairs of $\\sigma$-fields on a probability space. Here a somewhat restricted "cousin" of their result is presented for the same context, but involving in part an analogous measure of dependence based only on correlations of indicator functions. It was first proved by the author in an unpublished 1978 Ph.D. thesis. An example is constructed to show a limitation of this "cou...

  3. Recent Technological Developments in Cobalt Catalysts for Fischer-Tropsch Synthesis

    Institute of Scientific and Technical Information of China (English)

    Junling Zhang; Jiangang Chen; Yongwang Li; Yuhan Sun

    2002-01-01

    Co-based catalysts are often utilized due to their high Fischer-Tropsch synthesis (FT) activity,C+5 hydrocarbon selectivity, low water-gas shift reaction (WGS) activity and relatively low cost. Selective control of C5+ hydrocarbons and the catalyst longevity are critical in the design of cobalt catalysts.Thus, various methods to improve the performance of Co catalysts have been suggested. The progress in cobalt catalysts reviewed in the last few decades, mainly involved the support, promoter, preparation and deactivation of Co-based catalysts.

  4. Slurry phase Fischer-Tropsch synthesis: Cobalt plus a water-gas shift catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Yates, I.C.; Satterfield, C.N.

    1989-01-01

    The rate of synthesis gas consumption over a cobalt FischerTropsch catalyst was measured in a well-mixed, continuous-flow, slurry reactor at 220 to 240[degrees]C, 0.5 to 1.5 MPa, H[sub 2]/CO feed ratios of 1.5 to 3.5 and conversions of 7 to 68% of hydrogen and 11 to 73% of carbon monoxide. The inhibiting effect of carbon monoxide was determined quantitatively and a Langmuir-Hinshelwood-type equation of the following form was found to best represent the results: -R[sub H[sub 2+Co

  5. Macromolecules and Enzymes: The Geneva Heritage from Kurt H. Meyer and Edmond H. Fischer.

    Science.gov (United States)

    Fischer, Edmond H; Piguet, Alfred

    2009-12-01

    On the 26th May 2009, Edmond Fischer, winner with Ed Krebs of the Nobel prize in physiology or medicine in 1992, and his colleague at the time of his research activities at the Ecole de chimie of the University of Geneva, Alfred Piguet, met with Andreas Hauser, Claude Piguet and Howard Riezman of the Section de chimie et biochimie of the University of Geneva to talk about how they became scientists under the impetus of Kurt H. Meyer and what became of them thereafter.

  6. Fundaments of Quaternionic Clifford Analysis III: Fischer Decomposition in Symplectic Harmonic Analysis

    OpenAIRE

    Brackx, Fred; De Schepper, Hennie; Eelbode, David; Lavicka, Roman; Soucek, Vladimir

    2014-01-01

    In the framework of quaternionic Clifford analysis in Euclidean space $\\mathbb{R}^{4p}$, which constitutes a refinement of Euclidean and Hermitian Clifford analysis, the Fischer decomposition of the space of complex valued polynomials is obtained in terms of spaces of so--called (adjoint) symplectic spherical harmonics, which are irreducible modules for the symplectic group Sp$(p)$. Its Howe dual partner is determined to be $\\mathfrak{sl}(2,\\mathbb{C}) \\oplus \\mathfrak{sl}(2,\\mathbb{C}) = \\ma...

  7. Fischer-Tropsch synthesis over MOF-supported cobalt catalysts (Co@MIL-53(Al)).

    Science.gov (United States)

    Isaeva, V I; Eliseev, O L; Kazantsev, R V; Chernyshev, V V; Davydov, P E; Saifutdinov, B R; Lapidus, A L; Kustov, L M

    2016-07-26

    Novel nanohybrid materials were prepared by immobilizing Co nanoparticles on a microporous framework MIL-53(Al) as a porous host matrix. The synthesized cobalt-containing materials were characterized by XRD, STEM, and oxygen titration. The catalytic performance of Co@MIL-53(Al) nanohybrids was examined in Fischer-Tropsch synthesis (FTS) for the first time. A higher selectivity to C5+ hydrocarbons and lower selectivity to methane for Co@MIL-53(Al) as compared to conventional Co/Al2O3 were observed.

  8. Study on the Precursor Phase Composition of Fused Iron Catalyst for Fischer-Tropsch Synthesis

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The effect of the precursor composition of fused iron catalyst on the performance of Fischer-Tropsch synthesis was investigated. XRD, BET and CO2 adsorption experiments were carried out to provide better insight into the relationship therein. The results showed that the selectivity of C5+ hydrocarbon products was dependent on the mole ratio of Fe2+/Fe3+, which was represented by a hump-shaped curve. Catalysts with precursors containing Fe3O4 phase favored the magnetite spinal formation during F-T reaction, while Fe1-xO-based catalysts were more likely to favor the formation and growth of the iron carbide crystals.

  9. Memory design

    DEFF Research Database (Denmark)

    Tanderup, Sisse

    Mind and Matter - Nordik 2009 Conference for Art Historians Design Matters Contributed Memory design BACKGROUND My research concerns the use of memory categories in the designs by the companies Alessi and Georg Jensen. When Alessi's designers create their products, they are usually inspired...... by cultural forms, often specifically by the concept of memory in philosophy, sociology and psychology, while Danish design traditionally has been focusing on form and function with frequent references to the forms of nature. Alessi's motivation for investigating the concept of memory is that it adds...... a cultural dimension to the design objects, enabling the objects to make an identity-forming impact. Whether or not the concept of memory plays a significant role in Danish design has not yet been elucidated fully. TERMINOLOGY The concept of "memory design" refers to the idea that design carries...

  10. Disputed Memory

    DEFF Research Database (Denmark)

    The world wars, genocides and extremist ideologies of the 20th century are remembered very differently across Central, Eastern and Southeastern Europe, resulting sometimes in fierce memory disputes. This book investigates the complexity and contention of the layers of memory of the troubled 20th...... century in the region. Written by an international group of scholars from a diversity of disciplines, the chapters approach memory disputes in methodologically innovative ways, studying representations and negotiations of disputed pasts in different media, including monuments, museum exhibitions......, individual and political discourse and electronic social media. Analyzing memory disputes in various local, national and transnational contexts, the chapters demonstrate the political power and social impact of painful and disputed memories. The book brings new insights into current memory disputes...

  11. Synthesis of donor-acceptor alkynylcyclopropanes by diastereoselective cyclopropanation of electron-deficient alkenes with alkoxyalkynyl Fischer carbene complexes.

    Science.gov (United States)

    Barluenga, José; Fernández-Rodríguez, Manuel A; García-García, Patricia; Aguilar, Enrique; Merino, Isabel

    2005-12-16

    The reaction of electron-deficient alkenes with alkoxyalkynyl Fischer carbene complexes (FCCs) represents a straightforward route to a new type of captodative (donor-acceptor) alkynylcyclopropanes, which have been prepared in moderate to high yields and in a diastereoselective manner. Some studies regarding the employment of additives to facilitate the recovery of the metal moiety after the reaction are also described. Finally, the first example of a cyclopropanation reaction through employing Fischer carbene complexes under microwave irradiation is presented; this method proved to be an advantageous alternative to the thermal reaction.

  12. Main Memory

    OpenAIRE

    Boncz, Peter; Liu, Lei; Özsu, Tamer, M.

    2008-01-01

    Primary storage, presently known as main memory, is the largest memory directly accessible to the CPU in the prevalent Von Neumann model and stores both data and instructions (program code). The CPU continuously reads instructions stored there and executes them. It is also called Random Access Memory (RAM), to indicate that load/store instructions can access data at any location at the same cost, is usually implemented using DRAM chips, which are connected to the CPU and other peripherals (di...

  13. Aspen Process Flowsheet Simulation Model of a Battelle Biomass-Based Gasification, Fischer-Tropsch Liquefaction and Combined-Cycle Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    None

    1998-10-30

    This study was done to support the research and development program of the National Renewable Energy Laboratory (NREL) in the thermochemical conversion of biomass to liquid transportation fuels using current state-of-the-art technology. The Mitretek study investigated the use of two biomass gasifiers; the RENUGAS gasifier being developed by the Institute of Gas Technology, and the indirectly heated gasifier being developed by Battelle Columbus. The Battelle Memorial Institute of Columbus, Ohio indirectly heated biomass gasifier was selected for this model development because the syngas produced by it is better suited for Fischer-Tropsch synthesis with an iron-based catalyst for which a large amount of experimental data are available. Bechtel with Amoco as a subcontractor developed a conceptual baseline design and several alternative designs for indirect coal liquefaction facilities. In addition, ASPEN Plus process flowsheet simulation models were developed for each of designs. These models were used to perform several parametric studies to investigate various alternatives for improving the economics of indirect coal liquefaction.

  14. A balanced memory network.

    Directory of Open Access Journals (Sweden)

    Yasser Roudi

    2007-09-01

    Full Text Available A fundamental problem in neuroscience is understanding how working memory--the ability to store information at intermediate timescales, like tens of seconds--is implemented in realistic neuronal networks. The most likely candidate mechanism is the attractor network, and a great deal of effort has gone toward investigating it theoretically. Yet, despite almost a quarter century of intense work, attractor networks are not fully understood. In particular, there are still two unanswered questions. First, how is it that attractor networks exhibit irregular firing, as is observed experimentally during working memory tasks? And second, how many memories can be stored under biologically realistic conditions? Here we answer both questions by studying an attractor neural network in which inhibition and excitation balance each other. Using mean-field analysis, we derive a three-variable description of attractor networks. From this description it follows that irregular firing can exist only if the number of neurons involved in a memory is large. The same mean-field analysis also shows that the number of memories that can be stored in a network scales with the number of excitatory connections, a result that has been suggested for simple models but never shown for realistic ones. Both of these predictions are verified using simulations with large networks of spiking neurons.

  15. Co-Zn-Al based hydrotalcites as catalysts for Fischer-Tropsch process

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, C.L.; Pirola, C.; Boffito, D.C.; Di Fronzo, A. [Univ. degli Studi di Milano (Italy). Dipt. di Chimica Fisica ed Elettrochimica; Di Michele, A. [Univ. degli Studi di Perugia (Italy). Dipt. di Fisica; Vivani, R.; Nocchetti, M.; Bastianini, M.; Gatto, S. [Univ. degli Studi di Perugia (Italy). Dipt. di Chimica

    2011-07-01

    Co-Zn-Al based hydrotalcites have been investigated as catalysts for the well-known Fischer- Tropsch synthesis. A series of ternary hydrotalcites in nitrate form was prepared with the urea method in order to obtain active catalysts for the above mentioned process. The thermal activation at 350 C gives raise to finely dispersed metallic Co on the mixed oxides, so resulting in retaining the metal distribution of the parent compounds. An optimization study concerning the amount of cobalt of the prepared catalysts (range 15-70% mol, metal based) and the reaction temperature (220-260 C) is reported. All the samples have been fully characterized (BET, ICP-OES, XRPD, TG-DTA, FT-IR, SEM and TEM) and tested in a laboratory pilot plant. Tests to evaluate the stability of these materials were carried out in stressed conditions concerning both the activation and the operating temperatures and pressures (up to 350 C and 2.0 MPa). The obtained results suggest the possibility of using synthetic hydrotalcites as suitable Co-based catalysts for the Fischer-Tropsch synthesis. (orig.)

  16. Effect of clutch surface changes on the computerized pantographic reproducibility index and the Fischer angle.

    Science.gov (United States)

    Dupas, P H; Picart, B; Graux, F; Lefevre, C

    1987-05-01

    This study of eight patients compared the pantographic numeric data obtained with a concave clutch with those obtained with a flat clutch. The slight alterations that resulted were insignificant and varied with each patient. The only difference between Depoorter's study and this one is the manual calculation of the EPRI compared with the computerized calculation of CPRI. Small variation was found in the value of the Fischer angle when the studies were compared. As shown in Depoorter's work, the shape of the clutch does not produce any significant changes in the recording of the posterior determinants. This conclusion is confirmed by this study for both the CPRI and the value of the Fischer angle. The concave clutch and the flat clutch reproduced similar results in both studies. By altering the central bearing pin and obtaining the same interclutch distance for both clutches, we obtained results in this study that refute the findings of Scortecci that a concave clutch was superior to a flat clutch.

  17. Development and process evaluation of improved Fischer-Tropsch slurry catalysts. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Bukur, D.B.; Mukesh, D.; Patel, S.A.; Zimmerman, W.H.; Rosynek, M.P. [Texas A& M Univ., College Station, TX (United States); Kellogg, L.J. [Air Products and Chemicals, Inc., Allentown, PA (United States)

    1990-04-01

    This report describes results of a study aimed at developing and evaluating improved catalysts for a slurry Fischer-Tropsch (FT) process for converting synthesis gas to high quality transportation fuels (gasoline and distillate). The improvements in catalyst performance were sought by studying effects of pretreatment conditions, promoters and binders/supports. A total of 20 different, iron based, catalysts were evaluated in 58 fixed bed reactor tests and 10 slurry reactor tests. The major accomplishments and conclusions are summarized below. The pretreatment conditions (temperature, duration and the nature of reducing gas) have significant effect on catalyst performance (activity, selectivity and stability) during Fischer-Tropsch synthesis. One of precipitated unsupported catalysts had hydrocarbon selectivity similar to Mobil`s I-B catalyst in high wax mode operation, and had not experienced any loss in activity during 460 hours of testing under variable process conditions in a slurry reactor. The effect of promoters (copper and potassium) on catalyst performance during FT synthesis has been studied in a systematic way. It was found that potassium promotion increases activities of the FT and water-gas-shift (WGS) reactions, the average molecular weight of hydrocarbon products, and suppresses the olefin hydrogenation and isomerization reactions. The addition of binders/supports (silica or alumina) to precipitated Fe/Cu/K catalysts, decreased their activity but improved their stability and hydrocarbon selectivity. The performance of catalysts of this type was very promising and additional studies are recommended to evaluate their potential for use in commercial slurry reactors.

  18. Solid state NMR investigation of silica aerogel supported Fischer-Tropsch catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Zhiru; Dunn, Brian C.; Turpin, Gregory C.; Eyring, Edward M.; Ernst, Richard D.; Pugmire, Ronald J. [Department of Chemistry, University of Utah, Salt Lake City, UT 84112 (United States)

    2007-01-15

    The Fischer-Tropsch (F-T) catalyst is the critical component for the F-T synthesis of a variety of hydrocarbons from syngas. Fischer-Tropsch cobalt, iron and ruthenium catalysts supported on silica aerogel have been prepared using a combination of sol-gel chemistry and vapor phase deposition methods. Solid state NMR spectroscopy, a very powerful technique for analyzing the structure and dynamics of various materials, was employed in the study of these F-T catalyst systems. The silica aerogel supported F-T catalysts have been investigated using both solid state {sup 29}Si and {sup 13}C NMR methods. The silica aerogel's tetrahedral sub-unit structure and the influence of the loaded metal compounds have been observed. Three types of Si(O{sub 1/2}){sub 4} tetrahedral unit structure (Q{sub 2}, Q{sub 3} and Q{sub 4}) are clearly resolved in the silica aerogel samples. The calcining process and the loading of metal compounds produce line broadening in the {sup 29}Si spectra sufficient to prevent clear resolution of the three distinct Q{sub n} spectral lines, but the broadened spectra indicate that the three Q sub-unit structures are still present. The ferrocene and ruthenocene molecules used in the vapor phase deposition method exhibit a rapid exchange within the silica aerogel support similar to what one would expect in the gas or liquid state. (author)

  19. Fischer-Tropsch Synthesis on Multicomponent Catalysts: What Can We Learn from Computer Simulations?

    Directory of Open Access Journals (Sweden)

    José L. C. Fajín

    2015-01-01

    Full Text Available In this concise review paper, we will address recent studies based on the generalized-gradient approximation (GGA of the density functional theory (DFT and on the periodic slab approach devoted to the understanding of the Fischer-Tropsch synthesis process on transition metal catalysts. As it will be seen, this computational combination arises as a very adequate strategy for the study of the reaction mechanisms on transition metal surfaces under well-controlled conditions and allows separating the influence of different parameters, e.g., catalyst surface morphology and coverage, influence of co-adsorbates, among others, in the global catalytic processes. In fact, the computational studies can now compete with research employing modern experimental techniques since very efficient parallel computer codes and powerful computers enable the investigation of more realistic molecular systems in terms of size and composition and to explore the complexity of the potential energy surfaces connecting reactants, to intermediates, to products of reaction. In the case of the Fischer-Tropsch process, the calculations were used to complement experimental work and to clarify the reaction mechanisms on different catalyst models, as well as the influence of additional components and co-adsorbate species in catalyst activity and selectivity.

  20. Slurry phase Fischer-Tropsch synthesis: Cobalt plus a water-gas shift catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Chanenchuk, C.A.; Yates, I.C.; Satterfield, C.N.

    1990-01-01

    A Co/MgO/SiO[sub 2] Fischer-Tropsch catalyst was operated simultaneously with a Cu/ZnO/Al[sub 2]O[sub 3] water-gas-shift catalyst in a slurry reactor for over 400 hours. The process conditions were held constant at a temperature of 240[degrees]C, a pressure of 0.79 MPa, and a 1.1 H[sub 2]/CO feed of 0.065 Nl/min-g.cat. The Fischer-Tropsch activity remained constant at the level predicted by the operation of the Co/MgO/SiO[sub 2] catalyst alone. The water-gas-shift reaction was near equilibrium. The hydrocarbon product distribution of the combined catalyst system was stable and matched that of the CO/MgO/SiO[sub 2] operating alone under similar conditions. The combined catalyst system exhibited a high selectivity to n-alkanes. Neither catalysts's operation appeared to have a detrimental effect on that of the other, showing promise for future option.

  1. Synthesis in situ of gold nanoparticles by a dialkynyl Fischer carbene complex anchored to glass surfaces

    Science.gov (United States)

    Bertolino, María Candelaria; Granados, Alejandro Manuel

    2016-10-01

    In this work we present a detailed study of classic reactions such as "click reaction" and nucleophilic substitution reaction but on glass solid surface (slides). We used different reactive center of a dialkynylalcoxy Fischer carbene complex of tungsten(0) to be anchored to modified glass surface with amine, to obtain aminocarbene, and azide terminal groups. These cycloaddition reaction showed regioselectivity to internal triple bond of dialkynyl Fischer carbene complex without Cu(I) as catalyst. Anyway the carbene anchored was able to act as a reducing agent to produce in situ very stable gold nanoparticles fixed on surface. We showed the characterization of modified glasses by contact angle measurements and XPS. Synthesized nanoparticles were characterized by SEM, XPS, EDS and UV-vis. The modified glasses showed an important enhancement Raman-SERS. This simple, fast and robust method to create a polifunctional and hybrid surfaces can be valuable in a wide range of applications such as Raman-SERS substrates and other optical fields.

  2. Synthesis and catalytic properties of eggshell cobalt catalysts for the Fischer-Tropsch synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Iglesia, E. [Univ. of California, Berkeley, CA (United States); Soled, S.L.; Baumgartner, J.E. [Exxon Research and Engineering Co., Annandale, NJ (United States)] [and others

    1995-04-15

    CO diffusional restrictions decrease the rate and C{sup +}{sub 5} selectivity in large (1-3 mm) catalyst pellets required for Fischer-Tropsch synthesis in packed bed reactors. Eggshell catalysts, in which the active Co component is preferentially located near the outer pellet surface, decrease these transport restrictions and increase Fischer-Tropsch synthesis rates and C{sup +}{sub 5} selectivity. Maximum C{sup +}{sub 5} selectivities occur on catalysts with intermediate shell thickness, because these catalysts avoid intrapellet CO concentration gradients but still restrict the diffusive removal of reactive olefin products, which can readsorb and continue to grow to higher molecular weight hydrocarbons. Eggshell catalysts were prepared by a novel impregnation technique using molten cobalt nitrate. The eggshell thickness is controlled by the melt viscosity and by the contact time between the melt and the support pellet. These impregnation procedures and the slow reduction of the impregnated nitrate salts lead to relatively high cobalt dispersions (0.05-0.07) even at the high Co concentrations (40-50 wt%) present within the shell region. 51 refs., 8 figs., 4 tabs.

  3. Great Lakes Bathymetry

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lakes Michigan, Erie, Saint Clair, Ontario and Huron has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and...

  4. Great Indoors Awards 2007

    Index Scriptorium Estoniae

    2007-01-01

    Hollandis Maastrichtis jagati 17. XI esimest korda rahvusvahelist auhinda The Great Indoors Award. Aasta sisekujundusfirmaks valiti Masamichi Katayama asutatud Wonderwall. Auhinna said veel Zaha Hadid, Heatherwick Studio, Ryui Nakamura Architects ja Item Idem

  5. Flavor Memory

    NARCIS (Netherlands)

    Mojet, Jos; Köster, Ep

    2016-01-01

    Odor, taste, texture, temperature, and pain all contribute to the perception and memory of food flavor. Flavor memory is also strongly linked to the situational aspects of previous encounters with the flavor, but does not depend on the precise recollection of its sensory features as in vision and

  6. Memory integration

    NARCIS (Netherlands)

    Sweegers, C.C.G.

    2014-01-01

    The aim of this thesis was to characterize the neural mechanisms underlying memory integration. In chapter 2, we studied the neural underpinnings of regularity extraction across hippocampus-dependent episodic memories. We found higher connectivity between the hippocampus and the mPFC for the

  7. Shared Memories?

    DEFF Research Database (Denmark)

    Wæhrens, Anne

    2011-01-01

    This paper analyses how the memory of the Holocaust has been addressed in the European Parliament from 1989 to 2009. I identify two major changes that occurred in the 1990s and after the 2004 enlargement of the European Union respectively. In the 1990s the war in Bosnia and the question of restit......This paper analyses how the memory of the Holocaust has been addressed in the European Parliament from 1989 to 2009. I identify two major changes that occurred in the 1990s and after the 2004 enlargement of the European Union respectively. In the 1990s the war in Bosnia and the question...... of restitution universalised the memory of the Holocaust and made it present. The 2004 enlargement brought the memory of Soviet Communism into the Union and made it a central task to construct a community of memory that includes both the memory of the Holocaust and of Soviet Communism. The analysis also...... identifies what seems to be a political memory split between Left and Right; and it shows that the time might not be ripe for a shared European memory....

  8. Collaging Memories

    Science.gov (United States)

    Wallach, Michele

    2011-01-01

    Even middle school students can have memories of their childhoods, of an earlier time. The art of Romare Bearden and the writings of Paul Auster can be used to introduce ideas about time and memory to students and inspire works of their own. Bearden is an exceptional role model for young artists, not only because of his astounding art, but also…

  9. Main Memory

    NARCIS (Netherlands)

    P.A. Boncz (Peter); L. Liu (Lei); M. Tamer Özsu

    2008-01-01

    htmlabstractPrimary storage, presently known as main memory, is the largest memory directly accessible to the CPU in the prevalent Von Neumann model and stores both data and instructions (program code). The CPU continuously reads instructions stored there and executes them. It is also called Random

  10. Great ape foresight is looking great.

    Science.gov (United States)

    Osvath, Mathias

    2010-09-01

    Suddendorf, Corballis and Collier-Baker (Anim Cogn 12: 751-754, 2009) comment on a study on great ape foresight (Osvath and Osvath, Anim Cogn 11: 661-674, 2008). That study consisted of four experiments investigating foresight in chimpanzees and orangutans, examining in particular whether the planning they exhibit is best explained by assuming an episodic cognitive system. This system has widely been regarded as exclusive to humans. Indeed, the Bischof-Köhler hypothesis explicitly states that planning for a future need is outside the abilities of non-humans. In our paper, we argued that the results implied the presence of episodic abilities and challenged the Bischof-Köhler hypothesis. Suddendorf et al. are not ready to accept this claim. They critique each experiment in detail and maintain their view that episodic cognition is unique to humans. Here, I point out the misapprehensions and weaknesses in their critique notably a lack of appreciation for how the experiments in the study are interrelated and serve as controls for each other and for the baseline experiment. I reinforce my earlier conclusions with a number of recently published findings.

  11. Memory conformity affects inaccurate memories more than accurate memories.

    Science.gov (United States)

    Wright, Daniel B; Villalba, Daniella K

    2012-01-01

    After controlling for initial confidence, inaccurate memories were shown to be more easily distorted than accurate memories. In two experiments groups of participants viewed 50 stimuli and were then presented with these stimuli plus 50 fillers. During this test phase participants reported their confidence that each stimulus was originally shown. This was followed by computer-generated responses from a bogus participant. After being exposed to this response participants again rated the confidence of their memory. The computer-generated responses systematically distorted participants' responses. Memory distortion depended on initial memory confidence, with uncertain memories being more malleable than confident memories. This effect was moderated by whether the participant's memory was initially accurate or inaccurate. Inaccurate memories were more malleable than accurate memories. The data were consistent with a model describing two types of memory (i.e., recollective and non-recollective memories), which differ in how susceptible these memories are to memory distortion.

  12. Episodic memory decline and healthy aging

    NARCIS (Netherlands)

    Wang, W.C.; Daselaar, S.M.; Cabeza, R.

    2017-01-01

    One of the cognitive functions most affected by the aging process is our memory for personally experienced past events or episodic memory (EM). The advent of functional neuroimaging has greatly advanced our knowledge of the neural basis of EM and its decline with age. The current chapter revi

  13. A combined in situ XAS-XRPD-Raman study of Fischer-Tropsch synthesis over a carbon supported Co catalyst

    DEFF Research Database (Denmark)

    Tsakoumis, Nikolaos E.; Dehghan, Roya; Johnsen, Rune

    2013-01-01

    A cobalt based Fischer-Tropsch synthesis (FTS) catalyst, supported on a carbon nanofibers/carbon felt composite (Co/CNF/CF) was studied in situ at realistic conditions. The catalyst was monitored by Xray absorption spectroscopy (XAS), high-resolution X-ray powder diffraction (HR-XRPD) and Raman s...

  14. Reference test methods for total water in lint cotton by Karl Fischer Titration and low temperature distillation

    Science.gov (United States)

    In a study of comparability of total water contents (%) of conditioned cottons by Karl Fischer Titration (KFT) and Low Temperature Distillation (LTD) reference methods, we demonstrated a match of averaged results based on a large number of replications and weighing the test specimens at the same tim...

  15. The work of Otto Fischer and the historical development of his method of principal vectors for mechanism and machine science

    NARCIS (Netherlands)

    Wijk, van der Volkert; Herder, Just L.; Koetsier, T.; Ceccarelli, M.

    2012-01-01

    This article gives an overview of the distinctive work of Otto Fischer (1861-1916) on the motion of the human musculoskeletal system. In order to be able to derive the individual muscle forces for human in motion, he invented the method of principal vectors to describe the motion of the centers-of-m

  16. Subacute (28-day) toxicity of furfural in Fischer 344 rats: A comparison of the oral and inhalation route

    NARCIS (Netherlands)

    Arts, J.H.E.; Muijser, H.; Appel, M.J.; Kuper, C.F.; Bessems, J.G.M.; Woutersen, R.A.

    2004-01-01

    The subacute oral and inhalation toxicity of furfural vapour was studied in Fischer 344 rats to investigate whether route-to-route extrapolation could be employed to derive the limit value for inhalation exposure from oral toxicity data. Groups of 5 rats per sex were treated by gavage daily for 28 d

  17. Secondary reactions of primary products of the Fischer-Tropsch synthesis: Part 1. The role of ethene

    NARCIS (Netherlands)

    Snel, Ruud; Espinoza, Rafael L.

    1987-01-01

    Co-feeding experiments have shown that ethene readily initiates the Fischer-Tropsch synthesis without altering the chain-growth probability, even when it is present in high concentrations. Propagation by ethene was found to be unlikely. When present in concentrations of 5 mol% or higher, ethene sub

  18. Synthesis of Fischer indole derivatives using carboxyl-functionalized ionic liquid as an efficient and recyclable catalyst

    Institute of Scientific and Technical Information of China (English)

    Feng Ping Yi; Hai Yang Sun; Xian Hua Pan; Yuan Xu; Ji Zong Li

    2009-01-01

    Fischer indole cyclization of phenylhydrazine and various ketones using carboxyl-functionalized ionic liquid, 1-carboxymethyl-3-methylimidazolium tetrafluoroborate (abbreviated as [cmmim][BF4]) as catalyst was successfully performed. The yields of thetarget compounds were 80-92%, the purities were 96-98%. The catalyst could be rocovered and reused for at least six times without significant loss in activity.

  19. Effect of dietary galacto-oligosaccharides on azoxymethane-induced aberrant crypt foci and colorectal cancer in Fischer 344 rats

    NARCIS (Netherlands)

    Wijnands, M.V.W.; Schoterman, H.C.; Bruijntjes, J.P.; Hollanders, V.M.H.; Woutersen, R.A.

    2001-01-01

    The aim of the present study was to investigate the effects of galacto-oligosaccharides (GOS, Elix'or) on the development of aberrant crypt foci (ACF) and colorectal tumours in rats treated with azoxymethane (AOM). Two groups of 102 male Fischer 344 rats were injected twice with AOM to induce colore

  20. Silicon carbide coated with TiO2 with enhanced cobalt active phase dispersion for Fischer-Tropsch synthesis.

    Science.gov (United States)

    Liu, Yuefeng; Florea, Ileana; Ersen, Ovidiu; Pham-Huu, Cuong; Meny, Christian

    2015-01-04

    The introduction of a thin layer of TiO2 on β-SiC allows a significant improvement of the cobalt dispersion. This catalyst exhibits an excellent and stable catalytic activity for the Fischer-Tropsch synthesis (FTS) with high C5+ selectivity, which contributes to the development of a new active catalyst family in the gas-to-liquid process.

  1. In situ x-ray absorption of Co/Mn/TiO2 catalysts for Fischer-Tropsch synthesis

    NARCIS (Netherlands)

    Morales, F; de Groot, FMF|info:eu-repo/dai/nl/08747610X; Glatzel, P; Kleimenov, E; Bluhm, H; Havecker, M; Knop-Gericke, A; Weckhuysen, BM|info:eu-repo/dai/nl/285484397

    2004-01-01

    The reduction behavior of Co/TiO2 and Co/Mn/TiO2 catalysts for Fischer-Tropsch synthesis has been investigated by soft X-ray absorption spectroscopy (XAS). In situ XAS measurements of the L-2,L-3 edges of Co and Mn have been carried out during reduction treatments of the samples in H-2 at a pressure

  2. Different effects of diazepam in Fischer rats and two stocks of Wistar rats in tests of anxiety.

    Science.gov (United States)

    Bert, B; Fink, H; Sohr, R; Rex, A

    2001-01-01

    The behaviour of animals in tests of anxiety varies between strains, even in identical tests and surroundings. To evaluate the results obtained, a more detailed knowledge of the behaviour of different rat strains is indispensable. Identically raised Fischer 344 rats and two stocks of Wistar rats were examined in two animal tests of anxiety: the X-maze and a modified open-field test following diazepam treatment (0.5-4.0 mg/kg). Harlan-Wistar rats were the least 'anxious' when the behaviour of vehicle treated controls was compared. The largest effect of the anxiolytic diazepam, however, was observed in Harlan-Fischer rats. To determine possible reasons for strain and stock differences, plasma concentrations of diazepam and metabolites and concentrations of serotonin (5-HT) in the CNS were measured. Plasma concentrations of diazepam and metabolites differed between the strains with the Harlan-Fischer rats showing higher diazepam concentrations. 5-HT levels in discrete brain regions varied with Harlan-Fischer rats having higher 5-HT concentrations. Strain differences influence the anxiety-associated behaviour of untreated animals and the effect of anxiolytics.

  3. Fischer-tropsch synthesis on iron-based catalysts: the effect of co-feeding small oxygenates

    NARCIS (Netherlands)

    Snel, Ruud; Espinoza, Rafael L.

    1989-01-01

    Co-feeding experiments have shown that ethers can participate substantially in the Fischer-Tropsch synthesis with iron catalysts. Dimethyl ether is thought to be capable of building up surface complexes which are very similar to those naturally occurring during synthesis. Diethyl ether undergoes rap

  4. Case 3018. Cervus gouazoubira Fischer, 1814 (currently Mazama gouazoubira; Mammalia, Artiodactyla): proposed conservation as the correct original spelling

    Science.gov (United States)

    Gardner, A.L.

    1999-01-01

    The purpose of this application is to conserve the spelling of the specific name of Cervus gouazoubira Fischer, 1814 for the brown brocket deer of South America (family Cervidae). This spelling, rather than the original gouazoubira, has been in virtually universal usage for almost 50 years.

  5. Great Zimbabwe's water

    DEFF Research Database (Denmark)

    Pikirayi, Innocent; Sulas, Federica; Musindo, Tendai Treddah

    2016-01-01

    in the region's well-watered granite hills and valleys, and culminating in a vast urban and trading society. Later, c.1550 AD, it is argued, drying climate, land overexploitation, and changing regional trading patterns would lead to the decline of Great Zimbabwe. A review of this model is necessary since Great...... Zimbabwe and communities living around it survive in a region constantly threatened by water crises. However, we still know very little on the forms and uses of water and how these have influenced its development and demise. This article offers a multilayered review of available information on water......, including new records on environmental sequences, modern water sources, and provisioning models from in and around Great Zimbabwe. The integration of both old and new datasets allows us to follow the history of people-water interaction from early times to the present. We argue that understanding...

  6. Manipulations of attention dissociate fragile visual short-term memory from visual working memory.

    Science.gov (United States)

    Vandenbroucke, Annelinde R E; Sligte, Ilja G; Lamme, Victor A F

    2011-05-01

    People often rely on information that is no longer in view, but maintained in visual short-term memory (VSTM). Traditionally, VSTM is thought to operate on either a short time-scale with high capacity - iconic memory - or a long time scale with small capacity - visual working memory. Recent research suggests that in addition, an intermediate stage of memory in between iconic memory and visual working memory exists. This intermediate stage has a large capacity and a lifetime of several seconds, but is easily overwritten by new stimulation. We therefore termed it fragile VSTM. In previous studies, fragile VSTM has been dissociated from iconic memory by the characteristics of the memory trace. In the present study, we dissociated fragile VSTM from visual working memory by showing a differentiation in their dependency on attention. A decrease in attention during presentation of the stimulus array greatly reduced the capacity of visual working memory, while this had only a small effect on the capacity of fragile VSTM. We conclude that fragile VSTM is a separate memory store from visual working memory. Thus, a tripartite division of VSTM appears to be in place, comprising iconic memory, fragile VSTM and visual working memory. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Conversion enhancement of tubular fixed-bed reactor for Fischer-Tropsch synthesis using static mixer

    Institute of Scientific and Technical Information of China (English)

    Phavanee Narataruksa; Sabaithip Tungkamani; Karn Pana-Suppamassadu; Phongsak Keeratiwintakorn; Siriluck Nivitchanyong; Piyapong Hunpinyo; Hussanai Sukkathanyawat; Prayut Jiamrittiwong; Visarut Nopparat

    2012-01-01

    Recently,Fischer-Tropsch synthesis (FTS) has become an interesting technology because of its potential role in producing biofuels via Biomassto-Liquids (BTL) processes.In Fischer-Tropsch (FT) section,biomass-derived syngas,mainly composed of a mixture of carbon monoxide (CO)and hydrogen (H2),is converted into various forms of hydrocarbon products over a catalyst at specified temperature and pressure.Fixed-bed reactors are typically used for these processes as conventional FT reactors.The fixed-bed or packed-bed type reactor has its drawbacks,which are heat transfer limitation,i.e.a hot spot problem involved highly exothermic characteristics of FT reaction,and mass transfer limitation due to the condensation of liquid hydrocarbon products occurred on catalyst surface.This work is initiated to develop a new chemical reactor design in which a better distribution of gaseous reactants and hydrocarbon products could be achieved,and led to higher throughput and conversion.The main goal of the research is the enhancement of a fixed-bed reactor,focusing on the application of KenicsTM static mixer insertion in the tubular packed-bed reactor.Two FTS experiments were carried out using two reactors i.e.,with and without static mixer insertion within catalytic beds.The modeled syngas used was a mixed gas composed of H2/CO in 2 ∶ 1 molar ratio that was fed at the rate of 30 mL(STP)·min-1 (GHSV ≈ 136 mL·g-1cat·h-1) into the fixed Ru supported aluminum catalyst bed of weight 13.3 g.The reaction was carried out at 180 ℃ and atmospheric pressure continuously for 36 h for both experiments.Both transient and steady-state conversions (in terms of time on stream) were reported.The results revealed that the steady-state CO conversion for the case using the static mixer was approximately 3.5 times higher than that of the case without static mixer.In both cases,the values of chain growth probability of hydrocarbon products (α) for Fischer-Tropsch synthesis were 0.92 and 0.89 for

  8. Episodic memory: from mind to brain.

    Science.gov (United States)

    Tulving, Endel

    2002-01-01

    Episodic memory is a neurocognitive (brain/mind) system, uniquely different from other memory systems, that enables human beings to remember past experiences. The notion of episodic memory was first proposed some 30 years ago. At that time it was defined in terms of materials and tasks. It was subsequently refined and elaborated in terms of ideas such as self, subjective time, and autonoetic consciousness. This chapter provides a brief history of the concept of episodic memory, describes how it has changed (indeed greatly changed) since its inception, considers criticisms of it, and then discusses supporting evidence provided by (a) neuropsychological studies of patterns of memory impairment caused by brain damage, and (b) functional neuroimaging studies of patterns of brain activity of normal subjects engaged in various memory tasks. I also suggest that episodic memory is a true, even if as yet generally unappreciated, marvel of nature.

  9. [Episodic memory: from mind to brain].

    Science.gov (United States)

    Tulving, E

    2004-04-01

    Episodic memory is a neurocognitive (brain/mind) system, uniquely different from other memory systems, that enables human beings to remember past experiences. The notion of episodic memory was first proposed some 30 Years ago. At that time it was defined in terms of materials and tasks. It was subsequently refined and elaborated in terms of ideas such as self, subjective time, and autonoetic consciousness. This chapter provides a brief history of the concept of episodic memory, describes how it has changed (indeed greatly changed) since its inception, considers criticisms of it, and then discusses supporting evidence provided by (a) neuropsychological studies of patterns of memory impairment caused by brain damage, and (b) functional neuroimaging studies of patterns of brain activity of normal subjects engaged in various memory tasks. I also suggest that episodic memory is a true, even if as yet generally unappreciated, marvel of nature.

  10. Digital Extension of Music Memory Music as a Collective Cultural Memory

    Directory of Open Access Journals (Sweden)

    Dimitrije Buzarovski

    2014-11-01

    Full Text Available Artistic works represent a very important part of collective cultural memory. Every artistic work, by definition, can confirm its existence only through the presence in collective cultural memory. The migration from author’s individual memory to common collective cultural memory forms the cultural heritage. This equally applies to tangible and intangible cultural artifacts. Being part of collective cultural memory, music reflects the spatial (geographic and temporal (historic dimensions of this memory. Until the appearance of written signs (scores music was preserved only through collective cultural memory. Scores have facilitated further distribution of music artifacts. The appearance of different means for audio, and later audio/video recordings have greatly improved the distribution of music. The transition from analog to digital recording and carriers has been a revolutionary step which substantially extended the chances for the survival of music artifacts in collective memory.

  11. Great Expectations. [Lesson Plan].

    Science.gov (United States)

    Devine, Kelley

    Based on Charles Dickens' novel "Great Expectations," this lesson plan presents activities designed to help students understand the differences between totalitarianism and democracy; and a that a writer of a story considers theme, plot, characters, setting, and point of view. The main activity of the lesson involves students working in groups to…

  12. The Great Dismal Swamp

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This introduction to the natural history of the Great Dismal Swamp is presented at a time when 50,000 acres of the Swamp are being converted from private holdings to...

  13. The Great Lakes.

    Science.gov (United States)

    Seasons, 1987

    1987-01-01

    The Great Lakes are one of the world's greatest reserviors of fresh water, the foundation of Ontario's economic development, a primary force in ecological systems, and a base for pleasure and recreation. These lakes and their relationship with people of Canada and the United States can be useful as a subject for teaching the impact of human…

  14. Emissions from Diesel and Gasoline Vehicles Fuelled by Fischer-Tropsch Fuels and Similar Fuels

    DEFF Research Database (Denmark)

    Larsen, Ulrik; Lundorff, Peter; Ivarsson, Anders

    2007-01-01

    vehicles fuelled by Fischer Tropsch (FT) based diesel and gasoline fuel, compared to the emissions from ordinary diesel and gasoline. The comparison for diesel fuels was based on a literature review, whereas the gasoline comparison had to be based on our own experiments, since almost no references were...... and an alkylate fuel (Aspen), which was taken to be the ultimate formula of FT gasoline. FT based diesel generally showed good emission performance, whereas the FT based gasoline not necessary lead to lower emissions. On the other hand, the Aspen fuel did show many advantages for the emissions from the gasoline......The described investigation was carried out under the umbrella of IEA Advanced Motor Fuels Agreement. The purpose was to evaluate the emissions of carbon monoxide (CO), unburned hydrocarbons (HC), nitrogen oxides (NOx), particulate matter (PM) and polycyclic aromatic hydrocarbons (PAH) from...

  15. Study on iron-manganese catalysts for Fischer-Tropsch synthesis

    Institute of Scientific and Technical Information of China (English)

    MOSTAFA FEYZI; FATANEH JAFARI

    2012-01-01

    Iron-manganese catalysts were prepared by co-precipitation method.Characterization of catalysts was carried out by using X-ray diffraction (XRD),scanning electron microscopy (SEM),temperature program reduction (TPR),N2 adsorptiondesorption measurements.The results from catalytic performance tests in Fischer-Tropsch synthesis showed that the iron-manganese catalysts are supersensitive to catalyst composition and materials source.It was found that C2~4 light olefins increased while CH4 and CO2 decreased by using iron-manganese catalyst prepared from iron (Ⅱ) sulfate (A catalyst).The activity and selectivity of A catalyst was studied in different operational conditions.The results showed that the best operational conditions for C2~4 light olefins production were H2/CO=1/1 (GHSV=2 400 h-1) at 260 ℃ under 0.3 MPa total pressure.

  16. Kinetic Rates of the Fischer Tropsch Synthesis on a Co/Nb2O5 Catalyst

    Institute of Scientific and Technical Information of China (English)

    Víctor R.Ahón; Paulo L.C.Lage; Carlos D.D.de Souza; Fabiana M.Mendes; Martin Schmal

    2006-01-01

    The kinetics of the Fischer-Tropsch reaction over a Co/Nb2O5 catalyst in a fixed bed reactor was investigated experimentally. Experiments were carried out under isothermal and isobaric conditions (T=543 K, P=2.1 MPa) and under different conditions of several H2/CO feed molar ratio (0.49-4.79), space velocities (0.2-3.8 h-1), mass of catalyst (0.3-1.5 g), and CO conversion (10%-29%).Synthesis gas conversion was measured and data were reduced to estimate the kinetic parameters for different Langmuir-Hinshelwood rate expressions. Differential and integral reactor models were used for the nonlinear regression of kinetics parameters. One of the rate equations could well explain the data. The hydrocarbon product distributions that were experimentally determined exhibited an unusual behavior,and a possible explanation was discussed.

  17. Morphology Changes of Co Catalyst Nanoparticles at the Onset of Fischer-Tropsch Synthesis

    DEFF Research Database (Denmark)

    Høydalsvik, Kristin; Fløystad, Jostein B.; Voronov, Alexey

    2014-01-01

    Cobalt nanoparticles play an important role as catalysts for the Fischer-Tropsch synthesis, which is an attractive route for production of synthetic fuels. It is of particular interest to understand the varying conversion rate during the first hours after introducing synthesis gas (H-2 and CO...... of the cobalt particles, it is important to develop methods to gain surface-specific structural information under realistic processing conditions. We addressed this challenge using small-angle X-ray scattering (SAXS), a technique exploiting the penetrating nature of X-rays to provide information about particle...... morphology during in situ experiments. Simultaneous wide-angle X-ray scattering was used for monitoring the reduction from oxide to catalytically active metal cobalt, and anomalous SAXS was used for distinguishing the cobalt particles from the other phases present. After introducing the synthesis gas, we...

  18. Bridging complexes of rare earth and cobalt cluster as catalyst precursors for Fischer-Tropsch synthesis

    Institute of Scientific and Technical Information of China (English)

    ZENG Shanghong; DU Dongping; BAI Fenghua; SU Haiquan

    2011-01-01

    Three new bridging complexes of rare earth and cobalt cluster were synthesized and characterized via ICP, IR and TG techniques.The structure of the complexes was speculated as: two rare earth atoms were bridged with four CF3COO-, and rare earth atoms were coordinated with cobalt carbonyl clusters to form a steady structure. Application of the complexes as the catalyst precursors was explored for Fischer-Tropsch synthesis. The study showed that the bridging complexes of rare earth and cobalt cluster had large molecular size and were difficult to enter pore path of γ-Al2O3, so they were dispersed on the surface of γ-A12O3 support. In addition, the performance of Co(Ce)/γ-Al2O3 was the best among the catalysts with complex as precursor and maintained 77.7% CO conversion at 220 ℃ for 80 operation hours.

  19. Modeling of Fischer-Tropsch Synthesis in a Slurry Reactor with Water Permeable Membrane

    Institute of Scientific and Technical Information of China (English)

    Fabiano A. N. Fernandes

    2007-01-01

    Fischer-Tropsch synthesis is an important chemical process for the production of liquid fuels and olefins. In recent years, the abundant availability of natural gas and the increasing demand of olefins, diesel, and waxes have led to a high interest to further develop this process. A mathematical model of a slurry membrane reactor used for syngas polymerization was developed to simulate and compare the maximum yields and operating conditions in the reactor with that in a conventional slurry reactor.The carbon polymerization was studied from a modeling point of view in a slurry reactor with a water permeable membrane and a conventional slurry reactor. Simulation results show that different parameters affect syngas conversion and carbon product distribution, such as the hydrogen to carbon monoxide ratio,and the membrane parameters such as membrane permeance.

  20. Fischer matrices of Dempwolff group $2^{5}{^{cdot}}GL(5,2$

    Directory of Open Access Journals (Sweden)

    Ayoub Basheer Mohammed Basheer

    2012-12-01

    Full Text Available In cite{Demp2} Dempwolff proved the existence of a group of theform $2^{5}{^{cdot}}GL(5,2$ (a non split extension of theelementary abelian group $2^{5}$ by the general linear group$GL(5,2$. This group is the second largest maximal subgroup of thesporadic Thompson simple group $mathrm{Th}.$ In this paper wecalculate the Fischer matrices of Dempwolff group $overline{G} =2^{5}{^{cdot}}GL(5,2.$ The theory of projective characters isinvolved and we have computed the Schur multiplier together with aprojective character table of an inertia factor group. The fullcharacter table of $overline{G}$ is then can be calculated easily.

  1. Particle size effects in Fischer-Tropsch synthesis by Co catalyst supported on carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    Ali Nakhaei Pour; Elham Hosaini; Mohammad Izadyar; Mohammad Reza Housaindokht

    2015-01-01

    The effect of Co particle size on the Fischer-Tropsch synthesis (FTS) activity of carbon nanotube (CNT)-supported Co catalysts was investigated. Microemulsion (using water-to-surfactant molar ratios of 2 to12) and impregnation techniques were used to prepare catalysts with different Co particle sizes. Kinetic studies were performed to understand the effect of Co particle size on catalytic activity. Size-dependent kinetic parameters were developed using a thermodynamic method, to evaluate the structural sensitivity of the CNT-supported Co catalysts. The size-independent FTS reaction rate constant and size-independent adsorption parameter increased with increasing reac-tion temperature. The Polani parameter also depended on catalyst particle size, because of changes in the catalyst surface coverage.

  2. Effect of Several Anions on Fe-Based Catalyst for Fischer-Tropsch Synthesis

    Institute of Scientific and Technical Information of China (English)

    Jingchang Zhang; Xuehua Guo; Weiliang Cao

    2007-01-01

    The influence of several anions on Fe-based Fischer-Tropsch catalyst, used in the synthesis of light olefins from synthesis gas, was studied. The results indicated that the addition of anions resulted in the reduction of catalytic activity. When the anion content in the catalyst was 500 ppm, the influence of different anions on the catalysis activity was as follows: S2->Cl->SO42->NO3-. The addition of S2- improved the selectivity of total hydrocarbons in the products, and Cl- reduced this selectivity but increased the olefin content in the total hydrocarbons at the same time. When the contents of S2- and Cl- in the catalyst were less than 50 ppm, their influence could be ignored. The XRD results indicated that the addition of anions reduced the contents of a-Fe and Fe3C, which were the active components in the catalyst.

  3. Separation of Fischer-Tropsch Wax Products from Ultrafine Iron Catalyst Particles

    Energy Technology Data Exchange (ETDEWEB)

    Amitava Sarkar; James K. Neathery; Burtron H. Davis

    2006-12-31

    A fundamental filtration study was started to investigate the separation of Fischer-Tropsch Synthesis (FTS) liquids from iron-based catalyst particles. Slurry-phase FTS in slurry bubble column reactor systems is the preferred mode of operation since the reaction is highly exothermic. Consequently, heavy wax products in one approach may be separated from catalyst particles before being removed from the reactor system. Achieving an efficient wax product separation from iron-based catalysts is one of the most challenging technical problems associated with slurry-phase iron-based FTS and is a key factor for optimizing operating costs. The separation problem is further compounded by attrition of iron catalyst particles and the formation of ultra-fine particles.

  4. Morphological transformation during activation and reaction of an iron Fischer-Tropsch catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, N.B.; Kohler, S.; Harrington, M. [Sandia National Lab., Albuquerque, NM (United States)] [and others

    1995-12-31

    The purpose of this project is to support the development of slurry-phase bubble column processes being studied at the La Porte Alternative Fuel Development Unit. This paper describes the aspects of Sandia`s recent work regarding the advancement and understanding of the iron catalyst used in the slurry phase process. A number of techniques were used to understand the chemical and physical effects of pretreatment and reaction on the attrition and carbon deposition characteristics of iron catalysts. Unless otherwise stated, the data discussed was derived form experiments carried out on the catalyst chosen for the summer 1994 Fischer-Tropsch run at LaPorte, UCI 1185-78-370, (an L 3950 type) that is 88% Fe{sub 2}O{sub 3}, 11% CuO, and 0.052%K{sub 2}O.

  5. Preparation of Fischer-Tropsch catalysts from cobalt/iron hydrotalcites

    Energy Technology Data Exchange (ETDEWEB)

    Howard, B.H.; Boff, J.J.; Zarochak, M.F. [Pittsburgh Energy Technology Center, PA (United States)] [and others

    1995-12-31

    Compounds with the (hydrotalcites) have properties that make them attractive as precursors for Fischer-Tropsch catalysts. A series of single-phase hydrotalcites with cobalt/iron atom ratios ranging from 75/25 to 25/75 has been synthesized. Mixed cobalt/iron oxides have been prepared from these hydrotalcites by controlled thermal decomposition. Thermal decomposition at temperatures below 600 {degrees}C typically produced a single-phase mixed metal oxide with a spinel structure. The BET surface areas of the spinal samples have been found to be as high as about 150 m{sup 2}/g. Appropriate reducing pretreatments have been developed for several of these spinels and their activity, selectivity, and activity and selectivity maintenance have been examined at 13 MPa in a fixed-bed microreactor.

  6. Nucleophilic addition/double cyclization cascade processes between enynyl Fischer carbene complexes and alkynyl malonates.

    Science.gov (United States)

    Álvarez-Fernández, Ana; Suárez-Rodríguez, Tatiana; Suárez-Sobrino, Ángel L

    2014-07-18

    Two new selective cascade processes for enynyl Fischer carbene complexes 1 are described in their reaction with alkynyl malonates. When carbene complexes 1 react with the sodium enolate of homopropargyl malonates 3 a consecutive Michael-type addition/cyclopentannulation/6-exo cyclization takes place leading, in a regio- and stereoselective way, to n/5/6 angular tricyclic compounds 5. Furthermore, when propargylic malonates are used, a delayed protonation of the reaction mixture allows intermediate 1,4-addition adduct Ia to evolve through a 5-exo cyclization, consisting of an intramolecular nucleophilic attack from the central carbon of the allenylmetallate over the triple C-C bond. Further spontaneous cyclopentannulation of the resulting metallatriene gives rise to bicyclic and linear polycyclic compounds 6 and 7, some of them bearing a polyquinane framework.

  7. Coulometric trace determination of water by using Karl Fischer reagent and potentiometric end-point detection.

    Science.gov (United States)

    Cedergren, A

    1974-06-01

    A new approach to the determination of water via the Karl Fischer reaction is described. Iodine is coulometrically generated and the end-point corresponding to a slight excess of iodine, is detected potentiometrically with a non-polarized platinum electrode. Samples of 1-500 mul containing 0.05-200 mug of water were analysed with a standard deviation of 0.015 mug in the range 0.05-20 mug of H(2)O. A specially constructed electrolysis cell was used in combination with an LKB 16300 Coulometric Analyzer and the time for a complete analysis was 1-4 min, depending on sample size. The reagent composition has been optimized in order to enhance the rate of the main reaction and to minimize the extent of side-reactions. Decreasing the temperature reduced the extent of side-reactions. The displacement of end-point potential on dilution was studied and a correction is discussed.

  8. Co-CeO2/SiO2 Fischer-Tropsch Synthesis Catalyst

    Institute of Scientific and Technical Information of China (English)

    ShiHaibo; LiQiang; DaiXiaoping; YuChangchun; ShenShikong

    2005-01-01

    A series of Co (10.7 wt. %)-CeO2/SiO2 catalysts with various cerium contents was prepared and evaluated. The optimized ceria-promoted catalyst exhibits good activity, high selectivity towards long chain hydrocarbons, and excellent stability. The promotion mechanism of ceria was investigated using X-ray diffraction (XRD), temperature programmed reduction (TPR), H2 temperature programmed surface reaction (H2-TPSR) and transient response technique. It is suggested that the improved catalytic performance of the catalyst modified by ceria be attributed to (1) the improvement in the dispersion of metallic cobalt and the amount of active sites for Fischer-Tropsch Synthesis (FTS), leading to an increased concentration of surface active carbon species and high selectivity towards long chain hydrocarbons; (2) the inhibition of disproportionation of CO and the removal of inactive surface carbon species.

  9. The effect of aging on acetaminophen pharmacokinetics, toxicity and Nrf2 in Fischer 344 rats.

    Science.gov (United States)

    Mach, John; Huizer-Pajkos, Aniko; Cogger, Victoria C; McKenzie, Catriona; Le Couteur, David G; Jones, Brett E; de Cabo, Rafael; Hilmer, Sarah N

    2014-04-01

    We investigated the effect of aging on hepatic pharmacokinetics and the degree of hepatotoxicity following a toxic dose of acetaminophen. Young and old male Fischer 344 rats were treated with 800 mg/kg acetaminophen (young n = 8, old n = 5) or saline (young n = 9, old n = 9). Serum measurements showed old rats treated with acetaminophen had significantly lower serum alanine aminotransferase and higher acetaminophen and acetaminophen glucuronide levels and creatinine, compared with acetaminophen treated young rats (p acetaminophen had lower survival than those from old rats (52.4% ± 5.8%, young; 83.6% ± 1.7%, old, p acetaminophen-induced hepatotoxicity but may increase risk of nephrotoxicity in old age.

  10. Effect of incorporation manner of Zr promoter on precipitated ironbased catalysts for Fischer-Tropsch synthesis

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hao-jian; MA Hong-fang; ZHANG Hai-tao; YING Wei-yong; FANG Ding-ye

    2012-01-01

    The promotional effects of Zr on the structure,reduction,carburization and catalytic behavior of precipitated iron-based Fischer-Tropsch synthesis (FTS) catalysts were investigated.The catalysts were characterized by N2 physisorption,temperature-programmed reduction (TPR),and M(o)ssbauer effect spectroscopy (MES) techniques.As revealed by N2 physisorption,Zr decreased the BET surface area and pore volume of the catalyst.The results of TPR and MES show that Zr suppresses the reduction and carburization of Fe catalysts because of the interaction between Fe and Zr.The FTS reaction results indicate that Zr decreases the FTS activity of Fe catalysts but improves the catalysts' stability.In addition,Zr promoter restraines the formation of light hydrocarbons (methane and C2~C4) and shifts the production distribution to the heavy hydrocarbons.

  11. Optimisation of the Fischer-Tropsch process using zeolites for tail gas separation.

    Science.gov (United States)

    Perez-Carbajo, J; Gómez-Álvarez, P; Bueno-Perez, R; Merkling, P J; Calero, S

    2014-03-28

    This work is aimed at optimizing a Fischer-Tropsch Gas To Liquid (GTL) process by recycling compounds of the expelled gas mixture using zeolites for the separation. To that end, we have performed a computational study on four structures widely used in industry. A range of Si/Al ratios have been explored and the effects of their distribution assessed. The ability of the considered force fields and molecular models to reproduce experimental results has been widely proved in previously reported studies. Since this tail gas is formed by a five-component mixture, namely carbon dioxide, methane, carbon monoxide, nitrogen and hydrogen, molecular simulations present clear advantages over experiments. In addition, the viability of the Ideal Adsorption Solution Theory (IAST) has been evaluated to easily handle further separation steps. On the basis of the obtained results, we provide a separation scheme to perform sequentially the separation of CO2, CH4, CO, N2 and H2.

  12. Origins of Regioselectivity in the Fischer Indole Synthesis of a Selective Androgen Receptor Modulator.

    Science.gov (United States)

    Noey, Elizabeth L; Yang, Zhongyue; Li, Yanwei; Yu, Hannah; Richey, Rachel N; Merritt, Jeremy M; Kjell, Douglas P; Houk, K N

    2017-06-02

    The selective androgen receptor modulator, (S)-(7-cyano-4-(pyridin-2-ylmethyl)-1,2,3,4-tetrahydrocyclopenta[b]indol-2-yl)carbamic acid isopropyl ester, LY2452473, is a promising treatment of side effects of prostate cancer therapies. An acid-catalyzed Fischer indolization is a central step in its synthesis. The reaction leads to only one of the two possible indole regioisomers, along with minor decomposition products. Computations show that the formation of the observed indole is most favored energetically, while the potential pathway to the minor isomer leads instead to decomposition products. The disfavored [3,3]-sigmatropic rearrangement, which would produce the unobserved indole product, is destabilized by the electron-withdrawing phthalimide substituent. The most favored [3,3]-sigmatropic rearrangement transition state is bimodal, leading to two reaction intermediates from one transition state, which is confirmed by molecular dynamics simulations. Both intermediates can lead to the observed indole product, albeit through different mechanisms.

  13. Development of niobium-promoted cobalt catalysts on carbon nanotubes for Fischer-Tropsch synthesis

    Institute of Scientific and Technical Information of China (English)

    Sardar Ali; Noor Asmawati Mohd Zabidi; Duvvuri Subbarao

    2011-01-01

    Cobalt-based catalysts were prepared by a wet impregnation method on carbon nanotubes (CNTs) support and promoted with niobium.Samples were characterized by nitrogen adsorption,TEM,XRD,TPR,TPO and H2-TPD.Addition of niobium increased the dispersion of cobalt but decreased the catalysts reducibility.Fischer-Tropsch synthesis (FTS) was carried out in a fixed-bed microreactor at 543 K,1 atm and H2/CO =2 for 5 h.Addition of niobium enhanced the C5+ hydrocarbons selectivity by 39% and reduced methane selectivity by 59%.These effects were more pronounced for 0.04%Nb/Co/CNTs catalyst,compared with those observed for other niobium compositions.

  14. Trapping Planetary Noble Gases During the Fischer-Tropsch-Type Synthesis of Organic Materials

    Science.gov (United States)

    Nuth, Joseph A.; Johnson, N. M.; Meshik, A.

    2010-01-01

    When hydrogen, nitrogen and CO arc exposed to amorphous iron silicate surfaces at temperatures between 500 - 900K, a carbonaceous coating forms via Fischer-Tropsch type reactions!, Under normal circumstances such a catalytic coating would impede or stop further reaction. However, we find that this coating is a better catalyst than the amorphous iron silicates that initiate these rcactions:u . The formation of a self-perpetuating catalytic coating on grain surfaces could explain the rich deposits of macromolecular carbon found in primitive meteorites and would imply that protostellar nebulae should be rich in organic materiaL Many more experiments are needed to understand this chemical system and its application to protostellar nebulae.

  15. Intrinsic kinetics of eggshell cobalt catalysts for the Fischer-Tropsch synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Peluso, E.; Galarraga, C. E. [INTEVEP, S. A. Catalisis Aplicada, Caracas (Venezuela); De Lasa, H. I. [University of Western Ontario, Faculty of Engineering Science, London, ON (Canada)

    1998-05-01

    Production of synthetic hydrocarbons via the hydrogenation of carbon monoxide (Fischer-Tropsch synthesis, FT) as a means of producing clean fuels, and thus lessen the environmental burden, was discussed. To reduce transport limitations on the diffusion process through the catalytic pores, the use of pellicular or `eggshell` catalysts, especially eggshell Co-based catalysts, is recommended. These catalysts decrease the transport restrictions and therefore increase the FT reaction rates and C{sub 5}+ selectivity. The present study focuses on the kinetics of the FT reaction in an internally recycled Berty reactor over a Co-Zr/SiO{sub 2} eggshell catalyst by obtaining steady state reactivities at various H{sub 2}/CO ratios, temperatures and pressure ranges. Using statistical methods, the suitability of several kinetics models and possible reaction mechanisms in eggshell catalysts are analyzed. 3 refs.

  16. Immobilised carbon nanotubes as carrier for Co-Fischer-Tropsch synthesis catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Thiessen, J.; Rose, A.; Kiendl, I.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering; Curulla-Ferre, D. [Total S.A., Gas and Power, Paris La Defense (France)

    2011-07-01

    A possibility to immobilise carbon nanotubes (CNT) to make them applicable in a technical scale fixed bed reactor is studied. The approach to fabricate millimetre scale composites containing CNT presented in this work is to confine the nano-carbon in macro porous ceramic particles. Thus CNT were grown on the inner surface of silica and alumina pellets and spheres, respectively. Cobalt nano particles were successfully deposited on the carbon surface inside the two types of ceramic carriers and the systems were tested in Fischer - Tropsch synthesis (FTS). The cobalt mass related activity of these novel catalysts is similar to a conventional system. The selectivities of the Co/CNT/ceramic composites were compared with non supported CNT and carbon nanofibres (CNF). (orig.)

  17. The role of zeolites in the deactivation of multifunctional Fischer-Tropsch Synthesis catalysts: the interaction between HZSM-5 and Fe-based FT-catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Zonetti, P.C.; Gaspar, A.B.; Mendes, F.M.T.; Appel, L.G., E-mail: lucia.appel@int.gov.br [Instituto Nacional de Tecnologia (INT/MCT), Rio de Janeiro, RJ (Brazil); Avillez, R. R. de [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil); Sousa-Aguiar, E.F. [Centro de Pesquisa Leopoldo Americo Miguez de Mello (CENPES/PETROBRAS), Rio de Janeiro, RJ (Brazil)

    2013-10-15

    In order to produce gasoline directly from syngas, HZSM-5 can be added to the Fischer-Tropsch catalyst. However, this catalytic system shows an important deactivation rate. Aiming at describing this phenomenon, Fe-based catalysts and physical mixtures containing these catalysts and HZSM-5 were employed in this reaction. All these systems were characterized using the following techniques: XRD, XPS, TPR and TPD of CO. This work shows that HZSM-5 interacts with the Fe-based Fischer-Tropsch catalyst during the reduction step, decreasing the Fe concentration on the catalytic surface and thus lowering the activity of the catalytic system in the Fischer-Tropsch Synthesis. (author)

  18. The role of zeolites in the deactivation of multifunctional fischer-tropsch synthesis catalysts: the interaction between HZSM-5 and Fe-based Ft-catalysts

    Directory of Open Access Journals (Sweden)

    P. C. Zonetti

    2013-12-01

    Full Text Available In order to produce gasoline directly from syngas, HZSM-5 can be added to the Fischer-Tropsch catalyst. However, this catalytic system shows an important deactivation rate. Aiming at describing this phenomenon, Fe-based catalysts and physical mixtures containing these catalysts and HZSM-5 were employed in this reaction. All these systems were characterized using the following techniques: XRD, XPS, TPR and TPD of CO. This work shows that HZSM-5 interacts with the Fe-based Fischer-Tropsch catalyst during the reduction step, decreasing the Fe concentration on the catalytic surface and thus lowering the activity of the catalytic system in the Fischer-Tropsch Synthesis.

  19. Computational Fluid Dynamics Study of Channel Geometric Effect for Fischer-Tropsch Microchannel Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Na, Jonggeol; Jung, Ikhwan; Kshetrimayum, Krishnadash S.; Park, Seongho; Park, Chansaem; Han, Chonghun [Seoul National University, Seoul (Korea, Republic of)

    2014-12-15

    Driven by both environmental and economic reasons, the development of small to medium scale GTL(gas-to-liquid) process for offshore applications and for utilizing other stranded or associated gas has recently been studied increasingly. Microchannel GTL reactors have been preferred over the conventional GTL reactors for such applications, due to its compactness, and additional advantages of small heat and mass transfer distance desired for high heat transfer performance and reactor conversion. In this work, multi-microchannel reactor was simulated by using commercial CFD code, ANSYS FLUENT, to study the geometric effect of the microchannels on the heat transfer phenomena. A heat generation curve was first calculated by modeling a Fischer-Tropsch reaction in a single-microchannel reactor model using Matlab-ASPEN integration platform. The calculated heat generation curve was implemented to the CFD model. Four design variables based on the microchannel geometry namely coolant channel width, coolant channel height, coolant channel to process channel distance, and coolant channel to coolant channel distance, were selected for calculating three dependent variables namely, heat flux, maximum temperature of coolant channel, and maximum temperature of process channel. The simulation results were visualized to understand the effects of the design variables on the dependent variables. Heat flux and maximum temperature of cooling channel and process channel were found to be increasing when coolant channel width and height were decreased. Coolant channel to process channel distance was found to have no effect on the heat transfer phenomena. Finally, total heat flux was found to be increasing and maximum coolant channel temperature to be decreasing when coolant channel to coolant channel distance was decreased. Using the qualitative trend revealed from the present study, an appropriate process channel and coolant channel geometry along with the distance between the adjacent

  20. Fischer-Tropsch-synthesis fuels as diesel engine fuel - Fuel of the future

    Energy Technology Data Exchange (ETDEWEB)

    Olsson, Erik [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Thermo and Fluid Dynamics

    2000-04-01

    The Fischer-Tropsch (F-T) catalytic conversion process can be used to synthesize diesel fuels from a variety of feedstocks, including coal, natural gas and biomass. Synthetic diesel fuels can have very low sulfur and aromatic content, and excellent auto ignition characteristics. Moreover, Fischer-Tropsch diesel fuels may also be economically competitive with regular diesel fuel if produced in large volumes. The aim of this investigation is to reveal and analyze the effects of F-T fuels on a research diesel engine performance. Previous engine laboratory tests indicate that F-T fuels are promising alternative fuels because they can be used in unmodified diesel engines, and substantial quantitative exhaust emission reductions can be reached. Also substantial qualitative reductions, e.g. reduction of the number of hazardous chemicals and reduction of the concentration of hazardous chemicals in the exhausts may be realised. Since the engine performance is closely related to in-cylinder processes, a detailed thermodynamic analysis has been performed revealing the real thermochemistry history. The experimental results have shown that F-T fuels have a beneficial effect not only on the emission levels, but also on other energetic parameters of the engine. Heat release analysis have shown that ignition delay, cylinder peak pressure, heat release gradient and indicated efficiency are affected as well. Two different mixtures of FT-fuels with variation in carbon chain branching and, to a certain extent, variation in chain length were tested and their results were compared with those obtained from conventional fuel (MK1). The selected optimized F-T fuels mixture were further tested according to the 13 mode ECE R49 test cycle and were found as good competitive alternative diesel fuels.

  1. Isotopic tracer studies of Fischer-Tropsch Synthesis over Ru/TiO sub 2 catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Krishna, K.R.

    1992-01-01

    Fischer-Tropsch synthesis is a process in which CO and H{sub 2} react to give predominantly liquid hydrocarbons. The reaction can be considered a special type of polymerization in which the monomer is produced in situ, and chain growth occurs by a sequence of independently repeated additions of the monomer to the growing chain. A investigation has been conducted to study the CO hydrogenation reaction in order to better understand catalyst deactivation and the elementary surface processes involved in chain growth. Isotopic tracers are used in conjunction with transient-response techniques in this study of Fischer-Tropsch synthesis over Ru/TiO{sub 2} catalysts. Experiments are conducted at a total pressure of 1 atmosphere, reaction temperatures of 453--498 K and D{sub 2}/CO (or H{sub 2}/CO) ratios of 2--5. Synthesis products are analyzed by gas chromatography or isotope-ratio gas chromatography-mass spectrometry. Rate constants for chain initiation, propagation and termination are evaluated under steady-state reaction conditions by using transients in isotopic composition. The activation energy for chain termination is much higher than that for propagation, accounting for the observed decrease in the chain growth parameter are also estimated. Coverages by reaction intermediates are also estimated. When small amounts of {sup 12}C-labelled ethylene are added to {sup 13}CO/H{sub 2} synthesis gas, ethylene acts as the sole chain initiator. Ethylene-derived carbon also accounts for 45% of the C{sub 1} monomer pool. 102 refs., 29 figs., 11 tabs.

  2. Isotopic tracer studies of Fischer-Tropsch Synthesis over Ru/TiO{sub 2} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Krishna, K.R.

    1992-01-01

    Fischer-Tropsch synthesis is a process in which CO and H{sub 2} react to give predominantly liquid hydrocarbons. The reaction can be considered a special type of polymerization in which the monomer is produced in situ, and chain growth occurs by a sequence of independently repeated additions of the monomer to the growing chain. A investigation has been conducted to study the CO hydrogenation reaction in order to better understand catalyst deactivation and the elementary surface processes involved in chain growth. Isotopic tracers are used in conjunction with transient-response techniques in this study of Fischer-Tropsch synthesis over Ru/TiO{sub 2} catalysts. Experiments are conducted at a total pressure of 1 atmosphere, reaction temperatures of 453--498 K and D{sub 2}/CO (or H{sub 2}/CO) ratios of 2--5. Synthesis products are analyzed by gas chromatography or isotope-ratio gas chromatography-mass spectrometry. Rate constants for chain initiation, propagation and termination are evaluated under steady-state reaction conditions by using transients in isotopic composition. The activation energy for chain termination is much higher than that for propagation, accounting for the observed decrease in the chain growth parameter are also estimated. Coverages by reaction intermediates are also estimated. When small amounts of {sup 12}C-labelled ethylene are added to {sup 13}CO/H{sub 2} synthesis gas, ethylene acts as the sole chain initiator. Ethylene-derived carbon also accounts for 45% of the C{sub 1} monomer pool. 102 refs., 29 figs., 11 tabs.

  3. Componentes de dificultad de tareas de razonamiento deductivo aplicando el modelo LLTM de Fischer

    Directory of Open Access Journals (Sweden)

    María Silvia Galibert

    2015-01-01

    Full Text Available El razonamiento silogístico es parte importante del razonamiento deductivo. El análisis de las fuentes de error en la resolución de silogismos originó, den - tro de la psicología cognitiva, explicaciones como el efecto atmósfera, el sesgo de la figura y la conver - sión ilícita. En este trabajo se ajustó el modelo lltm de Fischer para identificar componentes de dificul - tad de silogismos y estimar sus efectos. Se adminis - traron 46 ítems con un diseño de enlace a tres gru - pos, con un total de 1074 estudiantes universitarios. Para cada par de premisas se debía escoger un es - quema de conclusión y completarlo con los términos extremos o reconocer la falta de conclusión válida. El modelo de Rasch se ajustó sobre un subconjun - to de 20 silogismos y se aplicó el modelo lltm de Fischer. Se identificaron, aumentando la dificultad, cuatro componentes: efecto atmósfera y sesgo de figura (cuando éstos están en dirección contraria a la conclusión o no hay conclusión válida, figura II y figura III. El carácter reversible de la conclusión (modos universal negativo y particular afirmativo y la falta de conclusión válida fueron componentes facilitadores. La correlación entre las estimaciones de los parámetros de dificultad bajo el modelo de Rasch y el lltm fue 0,96.

  4. Fischer 344 and Lewis Rat Strains as a Model of Genetic Vulnerability to Drug Addiction.

    Science.gov (United States)

    Cadoni, Cristina

    2016-01-01

    Today it is well acknowledged that both nature and nurture play important roles in the genesis of psychopathologies, including drug addiction. Increasing evidence suggests that genetic factors contribute for at least 40-60% of the variation in liability to drug dependence. Human genetic studies suggest that multiple genes of small effect, rather than single genes, contribute to the genesis of behavioral psychopathologies. Therefore, the use of inbred rat strains might provide a valuable tool to identify differences, linked to genotype, important in liability to addiction and related disorders. In this regard, Lewis and Fischer 344 inbred rats have been proposed as a model of genetic vulnerability to drug addiction, given their innate differences in sensitivity to the reinforcing and rewarding effects of drugs of abuse, as well their different responsiveness to stressful stimuli. This review will provide evidence in support of this model for the study of the genetic influence on addiction vulnerability, with particular emphasis on differences in mesolimbic dopamine (DA) transmission, rewarding and emotional function. It will be highlighted that Lewis and Fischer 344 rats differ not only in several indices of DA transmission and adaptive changes following repeated drug exposure, but also in hypothalamic-pituitary-adrenal (HPA) axis responsiveness, influencing not only the ability of the individual to cope with stressful events, but also interfering with rewarding and motivational processes, given the influence of corticosteroids on dopamine neuron functionality. Further differences between the two strains, as impulsivity or anxiousness, might contribute to their different proneness to addiction, and likely these features might be linked to their different DA neurotransmission plasticity. Although differences in other neurotransmitter systems might deserve further investigation, results from the reviewed studies might open new vistas in understanding aberrant

  5. Fischer 344 and Lewis rat strains as a model of genetic vulnerability to drug addiction

    Directory of Open Access Journals (Sweden)

    Cristina eCadoni

    2016-02-01

    Full Text Available Today it is well acknowledged that both nature and nurture play important roles in the genesis of psychopathologies, including drug addiction. Increasing evidence suggests that genetic factors contribute for at least 40-60 % of the variation in liability to drug dependence. Human genetic studies suggest that multiple genes of small effect, rather than single genes, contribute to the genesis of behavioral psychopathologies. Therefore the use of inbred rat strains might provide a valuable tool to identify differences, linked to genotype, important in liability to addiction and related disorders. In this regard, Lewis and Fischer 344 inbred rats have been proposed as a model of genetic vulnerability to drug addiction, given their innate differences in sensitivity to the reinforcing and rewarding effects of drugs of abuse, as well their different responsiveness to stressful stimuli. This review will provide evidence in support of this model for the study of the genetic influence on addiction vulnerability, with particular emphasis to differences in mesolimbic dopamine (DA transmission, rewarding and emotional function. It will be highlighted that Lewis and Fischer 344 rats differ not only in several indices of DA transmission and adaptive changes following repeated drug exposure, but also in hypothalamic-pituitary-adrenal (HPA axis responsiveness, influencing not only the ability of the individual to cope with stressful events, but also interfering with rewarding and motivational processes, given the influence of corticosteroids on dopamine neurons functionality.Further differences between the two strains, as impulsivity or anxiousness, might contribute to their different proneness to addiction, and likely these features might be linked to their different DA neurotransmission plasticity. Although differences in other neurotransmitter systems might deserve further investigations, results from the reviewed studies might open new vistas in

  6. Memory loss

    Science.gov (United States)

    A person with memory loss needs a lot of support. It helps to show the person familiar objects, music, or and photos or play familiar music. Write down when the person should take any medicine or do other ...

  7. Memory clinics

    OpenAIRE

    Jolley, D; Benbow, S M; Grizzell, M

    2006-01-01

    Memory clinics were first described in the 1980s. They have become accepted worldwide as useful vehicles for improving practice in the identification, investigation, and treatment of memory disorders, including dementia. They are provided in various settings, the setting determining clientele and practice. All aim to facilitate referral from GPs, other specialists, or by self referral, in the early stages of impairment, and to avoid the stigma associated with psychiatric services. They bring ...

  8. Great cities look small

    CERN Document Server

    Sim, Aaron; Barahona, Mauricio; Stumpf, Michael P H

    2015-01-01

    Great cities connect people; failed cities isolate people. Despite the fundamental importance of physical, face-to-face social-ties in the functioning of cities, these connectivity networks are not explicitly observed in their entirety. Attempts at estimating them often rely on unrealistic over-simplifications such as the assumption of spatial homogeneity. Here we propose a mathematical model of human interactions in terms of a local strategy of maximising the number of beneficial connections attainable under the constraint of limited individual travelling-time budgets. By incorporating census and openly-available online multi-modal transport data, we are able to characterise the connectivity of geometrically and topologically complex cities. Beyond providing a candidate measure of greatness, this model allows one to quantify and assess the impact of transport developments, population growth, and other infrastructure and demographic changes on a city. Supported by validations of GDP and HIV infection rates ac...

  9. Great Zimbabwe's water

    DEFF Research Database (Denmark)

    Pikirayi, Innocent; Sulas, Federica; Musindo, Tendai Treddah;

    2016-01-01

    , including new records on environmental sequences, modern water sources, and provisioning models from in and around Great Zimbabwe. The integration of both old and new datasets allows us to follow the history of people-water interaction from early times to the present. We argue that understanding......Once a thriving center with commercial links to the Indian Ocean, what remains of Great Zimbabwe is its monumental architecture. Its rise and decline have long been linked to environmental changes in southern Zimbabwe, beginning in the second half of the 13th century with agropastoralists thriving...... of the local environment was vital in managing both water excesses and shortages in the past, and show that some of this knowledge survives among indigenous communities linked to the site and living in the surrounding landscape. While nearby Masvingo town has persistently lived under water-emergency conditions...

  10. Effect of cobalt loading on reducibility,dispersion and crystallite size of Co/Al2O3 Fischer-Tropsch catalyst

    Institute of Scientific and Technical Information of China (English)

    熊海峰; 张煜华; 李金林; 古映莹

    2004-01-01

    Co/Al2O3 Fischer-Tropsch synthesis catalysts with different cobalt loadings were prepared using incipient wetness impregnation method. The effects of cobalt loading on the properties of catalysts were studied by means of X-ray diffraction (XRD), temperature programmed reduction (TPR), hydrogen temperature programmed desorption (H2-TPD) and O2 titration. Co-support compound formation can be detected in catalyst system by XRD.For the Co/Al2 O3 catalysts with low cobalt loading, CoAl2 O4 phase appears visibly. Two different reduction regions can be presented for Co/Al2O3 catalysts, which belong to Co3O4 crystallites (reduction at 320 ℃ ) and cobalt oxidealumina interaction species (reduction at above 400 C ). Increasing Co loading results in the increase of Co3 O4 crystallite size. The reduced Co/Al2 O3 catalysts have two adsorption sites, and cobalt loading greatly influences the adsorption behavior. With the increase of cobalt loading, the amount of low temperature adsorption is increased, the amount of high temperature adsorption is decreased, and the percentage reduction and cobalt crystallite size are increased.

  11. Not so Great Lakes?

    Science.gov (United States)

    Showstack, Randy

    In 1965, Frank Sinatra won the Grammy Award for his album, "September of My Years;" "Early Bird," the first commercial communications satellite, was launched; and Dr. Martin Luther King, Jr. was arrested in Selma, Alabama, during demonstrations against voter-registration rules.The year 1965 was also the last time water levels in the U.S. Great Lakes were as low as they are now.

  12. Great Lakes Energy Institute

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, J. Iwan [Case Western Reserve Univ., Cleveland, OH (United States)

    2012-11-18

    The vision of the Great Lakes Energy Institute is to enable the transition to advanced, sustainable energy generation, storage, distribution and utilization through coordinated research, development, and education. The Institute will place emphasis on translating leading edge research into next generation energy technology. The Institute’s research thrusts focus on coordinated research in decentralized power generation devices (e.g. fuel cells, wind turbines, solar photovoltaic devices), management of electrical power transmission and distribution, energy storage, and energy efficiency.

  13. A high-salt diet further impairs age-associated declines in cognitive, behavioral, and cardiovascular functions in male Fischer brown Norway rats.

    Science.gov (United States)

    Chugh, Gaurav; Asghar, Mohammad; Patki, Gaurav; Bohat, Ritu; Jafri, Faizan; Allam, Farida; Dao, An T; Mowrey, Christopher; Alkadhi, Karim; Salim, Samina

    2013-09-01

    Aging-associated declines in cognitive, emotional, and cardiovascular function are well known. Environmental stress triggers critical changes in the brain, further compromising cardiovascular and behavioral health during aging. Excessive dietary salt intake is one such stressor. Here, we tested the effect of high salt (HS) on anxiety, learning-memory function, and blood pressure (BP) in male Fischer brown Norway (FBN) rats. Adult (A; 2 mo) and old (O; 20 mo) male rats were fed normal-salt (NS; 0.4% NaCl) or HS (8% NaCl) diets for 4 wk after being implanted with telemeter probes for conscious BP measurement. Thereafter, tests to assess anxiety-like behavior and learning-memory were conducted. The rats were then killed, and samples of plasma, urine, and brain tissue were collected. We found that systolic BP was higher in O-NS (117 ± 1.2 mm Hg) than in A-NS (105 ± 0.8 mm Hg) rats (P < 0.05). Furthermore, BP was higher in O-HS (124 ± 1.4 mm Hg) than in O-NS (117 ± 1.2 mm Hg) rats (P < 0.05). Moreover, anxiety-like behavior (light-dark and open-field tests) was not different between A-NS and O-NS rats but was greater in O-HS rats than in A-NS, O-NS, or A-HS rats (P < 0.05). Short-term memory (radial arm water maze test) was similar in A-NS and O-NS rats but was significantly impaired in O-HS rats compared with A-NS, O-NS, or A-HS rats (P < 0.05). Furthermore, oxidative stress variables (in plasma, urine, and brain) as well as corticosterone (plasma) were greater in O-HS rats when compared with A-NS, O-NS, or A-HS rats (P < 0.05). The antioxidant enzyme glyoxalase-1 expression was selectively reduced in the hippocampus and amygdala of O-HS rats compared with A-NS, O-NS, or A-HS rats (P < 0.05), whereas other antioxidant enzymes, glutathione reductase 1, manganese superoxide dismutase (SOD), and Cu/Zn SOD remained unchanged. We suggest that salt-sensitive hypertension and behavioral derangement are associated with a redox imbalance in the brain of aged FBN rats.

  14. Bárbara Mujica, ed., Shakespeare and the Spanish «Comedia». Translation, Interpretation, Performance. Essays in Honor of Susan L. Fischer

    Directory of Open Access Journals (Sweden)

    Alejandro García-Reidy

    2016-01-01

    Full Text Available Reseña de Bárbara Mujica, ed., Shakespeare and the Spanish «Comedia». Translation, Interpretation, Performance. Essays in Honor of Susan L. Fischer, Bucknell University Press, Lewisburg, 2013, 298 pp. ISBN 9781611485172.

  15. Great software debates

    CERN Document Server

    Davis, A

    2004-01-01

    The industry’s most outspoken and insightful critic explains how the software industry REALLY works. In Great Software Debates, Al Davis, shares what he has learned about the difference between the theory and the realities of business and encourages you to question and think about software engineering in ways that will help you succeed where others fail. In short, provocative essays, Davis fearlessly reveals the truth about process improvement, productivity, software quality, metrics, agile development, requirements documentation, modeling, software marketing and sales, empiricism, start-up financing, software research, requirements triage, software estimation, and entrepreneurship.

  16. Idiopathic great saphenous phlebosclerosis.

    Directory of Open Access Journals (Sweden)

    Ahmadreza Jodati

    2013-06-01

    Full Text Available Arterial sclerosis has been extensively described but reports on venous sclerosis are very sparse. Phlebosclerosis refers to the thickening and hardening of the venous wall. Despite its morphological similarities with arteriosclerosis and potential morbid consequences, phlebosclerosis has gained only little attention. We report a 72 year old male with paralysis and atrophy of the right leg due to childhood poliomyelitis who was referred for coronary artery bypass surgery. The great saphenous vein, harvested from the left leg, showed a hardened cord-like obliterated vein. Surprisingly, harvested veins from the atrophic limb were normal and successfully used for grafting.

  17. Memory consolidation.

    Science.gov (United States)

    Squire, Larry R; Genzel, Lisa; Wixted, John T; Morris, Richard G

    2015-08-03

    Conscious memory for a new experience is initially dependent on information stored in both the hippocampus and neocortex. Systems consolidation is the process by which the hippocampus guides the reorganization of the information stored in the neocortex such that it eventually becomes independent of the hippocampus. Early evidence for systems consolidation was provided by studies of retrograde amnesia, which found that damage to the hippocampus-impaired memories formed in the recent past, but typically spared memories formed in the more remote past. Systems consolidation has been found to occur for both episodic and semantic memories and for both spatial and nonspatial memories, although empirical inconsistencies and theoretical disagreements remain about these issues. Recent work has begun to characterize the neural mechanisms that underlie the dialogue between the hippocampus and neocortex (e.g., "neural replay," which occurs during sharp wave ripple activity). New work has also identified variables, such as the amount of preexisting knowledge, that affect the rate of consolidation. The increasing use of molecular genetic tools (e.g., optogenetics) can be expected to further improve understanding of the neural mechanisms underlying consolidation. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.

  18. Is external memory memory? Biological memory and extended mind.

    Science.gov (United States)

    Michaelian, Kourken

    2012-09-01

    Clark and Chalmers (1998) claim that an external resource satisfying the following criteria counts as a memory: (1) the agent has constant access to the resource; (2) the information in the resource is directly available; (3) retrieved information is automatically endorsed; (4) information is stored as a consequence of past endorsement. Research on forgetting and metamemory shows that most of these criteria are not satisfied by biological memory, so they are inadequate. More psychologically realistic criteria generate a similar classification of standard putative external memories, but the criteria still do not capture the function of memory. An adequate account of memory function, compatible with its evolution and its roles in prospection and imagination, suggests that external memory performs a function not performed by biological memory systems. External memory is thus not memory. This has implications for: extended mind theorizing, ecological validity of memory research, the causal theory of memory.

  19. Decreased reward sensitivity in rats from the Fischer344 strain compared to Wistar rats is paralleled by differences in endocannabinoid signaling.

    Directory of Open Access Journals (Sweden)

    Theresa Brand

    Full Text Available BACKGROUND: The aim of the present study was to examine if differences in the endocannabinoid (ECB system might be linked to strain specific variations in reward-related behavior in Fischer344 (Fischer and Wistar rats. METHODOLOGY/PRINCIPAL FINDINGS: Two rat strains, the Fischer and the Wistar strain, were tested for different aspects of reward sensitivity for a palatable food reward (sweetened condensed milk, SCM in a limited-access intake test, a progressive ratio (PR schedule and the pleasure-attenuated startle (PAS paradigm. Additionally, basic differences in the ECB system and cannabinoid pharmacology were examined in both rat strains. Fischer rats were found to express lower reward sensitivity towards SCM compared to Wistar rats. These differences were observed for consummatory, motivational and hedonic aspects of the palatable food reward. Western blot analysis for the CB1 receptor and the ECB degrading enzyme fatty acid amide hydrolase (FAAH revealed a lower expression of both proteins in the hippocampus (HPC of Fischer rats compared to the Wistar strain. Furthermore, increased cannabinoid-stimulated extracellular-regulated kinase (ERK phosphorylation was detected in Wistar rats compared to the Fischer strain, indicating alterations in ECB signaling. These findings were further supported by the pharmacological results, where Fischer rats were found to be less sensitive towards the effects of the CB1 receptor antagonist/inverse agonist SR141716 and the cannabinoid agonist WIN 55,212-2. CONCLUSIONS/SIGNIFICANCE: Our present findings indicate differences in the expression of the CB1 receptor and FAAH, as well as the activation of ECB signaling pathways between Fischer and Wistar rats. These basic differences in the ECB system might contribute to the pronounced differences observed in reward sensitivity between both rat strains.

  20. Using the Web To Explore the Great Depression.

    Science.gov (United States)

    Chamberlin, Paul

    2001-01-01

    Presents an annotated list of Web sites that focus on the Great Depression. Includes the American Experience, American Memory, the National Archives and Records Administration, and the New Deal Network Web sites. Offers additional sites covering topics such as the Jersey homesteads and labor history. (CMK)

  1. Development of a CO2 Tolerant Fischer-Tropsch Catalyst:from Laboratory to Commercial-Scale Demonstration in Alaska

    Institute of Scientific and Technical Information of China (English)

    Joep J H M Font Freide; Tim D Gamlin; J Richard Hensman; Barry Nay; Christopher Sharp

    2004-01-01

    This article describes the development of BP's Fischer-Tropsch catalyst, used for the conversion of carbon monoxide and hydrogen into liquid hydrocarbons. It covers the 18 year period from the early eighties, when laboratory scale preparations and micro-reactors were heavily used, right through to the present day with the commercial scale manufacture and proving of the finished catalyst in BP's new $86 million gas to liquids demonstration facility in Nikiski, Alaska. Extensive performance testing and scale-up experiments have been successfully carried out, all proof that a laboratory preparation can indeed be translated into a commercial manufacturing process. In addition, the resulting catalyst does not only meet the process design targets, but also exhibits enhanced stability and is tolerant to carbon dioxide.Above all, a commercial scale, fixed bed Fischer-Tropsch catalyst is now available and ready for licensing.Manufacturing procedures and quality control have all been successfully detailed and transferred to the commercial manufacturer.

  2. Techno-economic assessment of integrating methanol or Fischer-Tropsch synthesis in a South African sugar mill.

    Science.gov (United States)

    Petersen, Abdul M; Farzad, Somayeh; Görgens, Johann F

    2015-05-01

    This study considered an average-sized sugar mill in South Africa that crushes 300 wet tonnes per hour of cane, as a host for integrating methanol and Fischer-Tropsch synthesis, through gasification of a combined flow of sugarcane trash and bagasse. Initially, it was shown that the conversion of biomass to syngas is preferably done by catalytic allothermal gasification instead of catalytic autothermal gasification. Thereafter, conventional and advanced synthesis routes for both Methanol and Fischer-Tropsch products were simulated with Aspen Plus® software and compared by technical and economic feasibility. Advanced FT synthesis satisfied the overall energy demands, but was not economically viable for a private investment. Advanced methanol synthesis is also not viable for private investment since the internal rate of return was 21.1%, because it could not provide the steam that the sugar mill required. The conventional synthesis routes had less viability than the corresponding advanced synthesis routes.

  3. [Michael Fischer (1887-1948)--life and work of an important founder of Catholic nursing in Germany].

    Science.gov (United States)

    Kolling, H

    2000-08-01

    In 1919, Michael Fischer OSC was appointed to the German charity union "Zentrale des Deutschen Caritasverbandes" (DCV) in Freiburg. He assumed his duties as the acting manager and general secretary for the German catholic union of health institutions "Verband Katholischer Kranken- und Pflegeanstalten". For nearly twenty years, he was involved in expanding and strengthening this specialized organisation. For more than a decade, Michael Fischer influenced catholic medical care in Germany by holding lectures; on the whole, he published the medical welfare journal "Krankendienst" as well as fifteen specialized books and more than five hundred articles in different journals, which were essential. For all his efforts, his enormous engagement, historical health research has ignored him until now. The following essay is meant to give insight into his life and works and pays tribute to his importance in nursing care.

  4. Metal-carbon nanosystem IR-PVA/Fe-Co for catalysis in the Fischer-Tropsch synthesis

    Science.gov (United States)

    Vasilev, A. A.; Dzidziguri, E. L.; Ivantsov, M. I.; Efimov, M. N.

    2016-08-01

    Metal-carbon nanosystems consisting of nanodimensional bimetallic particles of Fe- Co dispersed in a carbon matrix for the Fischer-Tropsch synthesis were studied. Prepared metal-carbon nanopowders samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). It was shown formation of FeCo nanoparticles with body-centered cubic structures started at 400 °C. FeCo nanoparticles have spherical form, the mean size is 7 - 12 nm and uniform distribution in a carbon matrix. The metal-carbon nanosystem demonstrates a catalytic activity in the Fischer- Tropsch synthesis. The maximum yield of liquid hydrocabons C5+ was 92 g/m3 while the selectivity for the target product - 35%.

  5. Memory training in depression

    NARCIS (Netherlands)

    Becker, E.S.; Vanderhasselt, M.A.; Vrijsen, J.N.

    2015-01-01

    Memory biases, that is, general memory impairments as well as specific mood-congruent memory biases, are important vulnerability factors in depression. Recently, computerized memory trainings have been developed to target these biases, reducing rumination and lightening depressive symptoms. This

  6. Mechanistic role of water on the rate and selectivity of Fischer-Tropsch synthesis on ruthenium catalysts.

    Science.gov (United States)

    Hibbitts, David D; Loveless, Brett T; Neurock, Matthew; Iglesia, Enrique

    2013-11-18

    Water increases Fischer-Tropsch synthesis (FTS) rates on Ru through H-shuttling processes. Chemisorbed hydrogen (H*) transfers its electron to the metal and protonates the O-atom of CO* to form COH*, which subsequently hydrogenates to *HCOH* in the kinetically relevant step. H2 O also increases the chain length of FTS products by mediating the H-transfer steps during reactions of alkyl groups with CO* to form longer-chain alkylidynes and OH*.

  7. Peroxide effects of iodide excess on mitochondria in Fischer rat thyroid cell line in the early period

    Institute of Scientific and Technical Information of China (English)

    李敏

    2014-01-01

    Objective To investigate the peroxide effects of iodide excess on mitochondria in Fischer rat thyroid cell line(FRTL)in the early period.Methods After treatment with 0.0 mmol/L(control group)or 0.1 mmol/L potassium iodide(KI)for 2,4 and 24 h,respectively,changes of mitochondrial superoxide formation were assayed by flow cytometry and fluorescence microscopy using mitochondria-targeted hydroethidine(Mito SOX).

  8. Structure and Development of the Gametophytes of Philippine Cheilanthoid Ferns, III. Cheilanthes concolor (Langsdorff et Fischer R. Tryon

    Directory of Open Access Journals (Sweden)

    Prescillano Zamora

    1993-12-01

    Full Text Available The gametophytes of Cheilanthes concolor (Langsdorff et Fischer R. Tryon from the Philippines (Quezon City are no different in pattern of development and in morphology from those from India with one possible notable difference, which is, that the gametophytes under report (which were grown from spores produced from 32-sporate sporangia are apogamous while those from India (sporangial type of source was not stated are sexual.

  9. One-pot three-component synthesis of quinoxaline and phenazine ring systems using Fischer carbene complexes

    Directory of Open Access Journals (Sweden)

    Priyabrata Roy

    2010-05-01

    Full Text Available One-pot three-component coupling of o-alkynylheteroaryl carbonyl derivatives with Fischer carbene complexes and dienophiles leading to the synthesis of quinoxaline and phenazine ring systems has been investigated. This involves the generation of furo[3,4-b]pyrazine and furo[3,4-b]quinoxaline as transient intermediates, which were trapped with Diels–Alder dienophiles. This is the first report on furo[3,4-b]pyrazine intermediates.

  10. On the Superior Activity and Selectivity of PtCo/Nb2O5 Fischer-Tropsch Catalysts

    NARCIS (Netherlands)

    den Otter, J. H.; Yoshida, H.; Ledesma, C.; Chen, D.; de Jong, K. P.

    2016-01-01

    In this study Co/Nb2O5 catalysts and the effect of Pt-promotion thereon are investigated in comparison with γ-Al2O3- and α-Al2O3-supported catalysts for the Fischer-Tropsch (FT) synthesis. Upon Pt-promotion of Co/Nb2O5 the cobalt-weight normalized FT activity was found to increase by a factor of

  11. TRANSPORT COSTS AND THEIR IMPACT ON TRAIDING TROUGH SIMULATIONS IN A SPECIFIED DORNBRUCH-FISCHER -SAMUELSON MODEL - 1977

    Directory of Open Access Journals (Sweden)

    Viorica Puscaciu

    2008-05-01

    Full Text Available We propose here a brief presentation of the Ricardian model with continuum of goods knownas the Dormbusch-Fischer-Samuelson-1997, by the name of the ones who created it. Starting from thistheoretical base we will create numerous examples which will be made by an informatic program and we willconcentrate over the impact on transport costs at countries levels .We want to measure the transport impactover the countries specializations and over the range of good trades.

  12. Transport Costs and their Impact on Trading through Simulations in a Specified Dornbruch-Fischer -Samuelson Model-1977

    Directory of Open Access Journals (Sweden)

    Viorica Puscaciu

    2008-10-01

    Full Text Available We propose here a brief presentation of the Ricardian model with continuum of goods known as the Dormbusch-Fischer-Samuelson-1997,named by the ones who created it. Starting from this theoretical basis we will create numerous examples made by an informatics program and we willfocus over the impact on transport costs at the level of countries .We want to measure the transport impact over the countries specializations and overthe range of good trades.

  13. Great Britain at CERN

    CERN Multimedia

    2006-01-01

    From 14 to 16 November 2006 Administration Building, Bldg. 60/61 - ground and 1st floor 09.30 - 17.30 Fifteen companies will present their latest technologies at the 'Great Britain at CERN' exhibition. British industry will exhibit products and technologies related to the field of particle physics. The main fields represented will be computing technologies, electrical engineering, electronics, mechanical engineering, vacuum & low temperature technologies and particle detectors. The exhibition is organised by BEAMA Exhibitions (the British Electrotechnical and Allied Manufacturers Association). Below you will find: a list of the exhibitors. A detailed programme will be available in due course: from your Departmental secretariat, from the Reception information desk, Building 33, at the exhibition itself. A detailed list of the companies is available at the following FI link: http://fi-dep.web.cern.ch/fi-dep/structure/memberstates/exhibitions_visits.htm LIST OF EXHIBITORS 3D Metrics Alma...

  14. Great Britain at CERN

    CERN Multimedia

    2006-01-01

    From 14 to 16 November 2006 Administration Building, Bldg. 60/61 - ground and 1st floor 09.30 - 17.30 Fifteen companies will present their latest technologies at the 'Great Britain at CERN' exhibition. British industry will exhibit products and technologies related to the field of particle physics. The main fields represented will be computing technologies, electrical engineering, electronics, mechanical engineering, vacuum & low temperature technologies and particle detectors. The exhibition is organised by BEAMA Exhibitions (the British Electrotechnical and Allied Manufacturers Association). Below you will find: a list of the exhibitors. A detailed programme will be available in due course: from your Departmental secretariat, from the Reception information desk, Building 33, at the exhibition itself. A detailed list of the companies is available at the following FI link: http://fi-dep.web.cern.ch/fi-dep/structure/memberstates/exhibitions_visits.htm LIST OF EXHIBITORS 3D Metrics Almat...

  15. The Great Scientists

    Science.gov (United States)

    Meadows, Jack

    1989-11-01

    This lively history of the development of science and its relationship to society combines vivid biographies of twelve pivotal scientists, commentary on the social and historical events of their time, and over four hundred illustrations, including many in color. The biographies span from classical times to the Atomic Age, covering Aristotle, Galileo, Harvey, Newton, Lavoisier, Humboldt, Faraday, Darwin, Pasteur, Curie, Freud, and Einstein. Through the biographies and a wealth of other material, the volume reveals how social forces have influenced the course of science. Along with the highly informative color illustrations, it contains much archival material never before published, ranging from medieval woodcuts, etchings from Renaissance anatomy texts, and pages from Harvey's journal, to modern false-color x-rays and infrared photographs of solar flares. A beautifully-designed, fact-filled, stimulating work, The Great Scientists will fascinate anyone with an interest in science and how history can influence scientific discovery.

  16. Metal (Fe, Co, Ni) supported on different aluminas as Fischer-Tropsch catalyst

    Science.gov (United States)

    Dahlan, Marsih, I. Nyoman; Makertihartha, I. G. B. N.; Praserthdam, Piyasan; Panpranot, Joongjai; Ismunandar

    2015-09-01

    This research aimed to compare the physico-chemical properties of the same metal M (M = iron, cobalt, nickel) supported on aluminas with different morphology and pore size as Fischer-Tropsch catalyst. The aluminas applied as support were alumina synthesized through hydrothermal process, alumina formed by pretreatment of catapal and commercial alumina which named as Ahy, Aca, and Aco respectively. Ahy has uniform morphology of nanotubes while Aca and Aco showed non-uniform morphology of particle lumps. The particle lumps of Aca were larger than those of Aco. Ahy, Aca, and Aco respectively has average pore diameter of 2.75, 2.86 and 2.9 nm. Metals were deposited on the supports by incipient-wetness impregnation method. The catalysts were characterized by XRD, H2-TPR, and H2 chemisorption. Catalyst acitivity test for Fischer-Tropsch reaction was carried out in a micro reactor at 200 °C and 1 atm, and molar ratio of H2/CO = 2:1. The metal oxide particle size increased in the order M/Aco < M/Aca < M/Ahy. The catalysts reducibility also increased according to the order M/Aco < M/Aca < M/Ahy suggesting that the larger metal oxide particles are more reducible. The number of active site was not proportional to the reducibility because during the reduction, larger metal oxide particles were converted into larger metal particles. On the other hand, the number of active sites was inversely proportional to the particle sizes. The number of active site increased in the order M/Ahy < M/Aco < M/Aca. The catalytic activity also increased in the following order M/Ahy < M/Aco < M/Aca. The activity per active site increased according to the order M/Aca < M/Aco < M/Ahy meaning that for M/Ahy, a little increase in active site will lead to a significance increase in catalytic activity. It showed that Ahy has potential for the better support.

  17. Metal (Fe, Co, Ni) supported on different aluminas as Fischer-Tropsch catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Dahlan [Chemistry Education Study Program, Universitas Halu Oleo, Jl. HEA Mokodompit, Kendari 93232 (Indonesia); Marsih, I. Nyoman, E-mail: nyoman@chem.itb.ac.id; Ismunandar [Inorganic and Physical Chemistry Division, Departement of Chemistry, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia); Makertihartha, I. G. B. N. [Department of Chemical Engineering, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia); Praserthdam, Piyasan; Panpranot, Joongjai [Center of Excellence on Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Chulalongkorn University, 254 Phayathai Road, Bangkok 10330 (Thailand)

    2015-09-30

    This research aimed to compare the physico-chemical properties of the same metal M (M = iron, cobalt, nickel) supported on aluminas with different morphology and pore size as Fischer-Tropsch catalyst. The aluminas applied as support were alumina synthesized through hydrothermal process, alumina formed by pretreatment of catapal and commercial alumina which named as Ahy, Aca, and Aco respectively. Ahy has uniform morphology of nanotubes while Aca and Aco showed non-uniform morphology of particle lumps. The particle lumps of Aca were larger than those of Aco. Ahy, Aca, and Aco respectively has average pore diameter of 2.75, 2.86 and 2.9 nm. Metals were deposited on the supports by incipient-wetness impregnation method. The catalysts were characterized by XRD, H{sub 2}-TPR, and H{sub 2} chemisorption. Catalyst acitivity test for Fischer-Tropsch reaction was carried out in a micro reactor at 200 °C and 1 atm, and molar ratio of H{sub 2}/CO = 2:1. The metal oxide particle size increased in the order M/Aco < M/Aca < M/Ahy. The catalysts reducibility also increased according to the order M/Aco < M/Aca < M/Ahy suggesting that the larger metal oxide particles are more reducible. The number of active site was not proportional to the reducibility because during the reduction, larger metal oxide particles were converted into larger metal particles. On the other hand, the number of active sites was inversely proportional to the particle sizes. The number of active site increased in the order M/Ahy < M/Aco < M/Aca. The catalytic activity also increased in the following order M/Ahy < M/Aco < M/Aca. The activity per active site increased according to the order M/Aca < M/Aco < M/Ahy meaning that for M/Ahy, a little increase in active site will lead to a significance increase in catalytic activity. It showed that Ahy has potential for the better support.

  18. Fischer-Tropsch synthesis in supercritical phase carbon dioxide: Recycle rates

    Science.gov (United States)

    Soti, Madhav

    With increasing oil prices and attention towards the reduction of anthropogenic CO2, the use of supercritical carbon dioxide for Fischer Tropsch Synthesis (FTS) is showing promise in fulfilling the demand of clean liquid fuels. The evidence of consumption of carbon dioxide means that it need not to be removed from the syngas feed to the Fischer Tropsch reactor after the gasification process. Over the last five years, research at SIUC have shown that FTS in supercritical CO2reduces the selectivities for methane, enhances conversion, reduces the net CO2produces in the coal to liquid fuels process and increase the life of the catalyst. The research has already evaluated the impact of various operating and feed conditions on the FTS for the once through process. We believe that the integration of unreacted feed recycle would enhance conversion, increase the yield and throughput of liquid fuels for the same reactor size. The proposed research aims at evaluating the impact of recycle of the unreacted feed gas along with associated product gases on the performance of supercritical CO2FTS. The previously identified conditions will be utilized and various recycle ratios will be evaluated in this research once the recycle pump and associated fittings have been integrated to the supercritical CO2FTS. In this research two different catalysts (Fe-Zn-K, Fe-Co-Zn-K) were analyzed under SC-FTS in different recycle rate at 350oC and 1200 psi. The use of recycle was found to improve conversion from 80% to close to 100% with both catalysts. The experiment recycle rate at 4.32 and 4.91 was clearly surpassing theoretical recycle curve. The steady state reaction rate constant was increased to 0.65 and 0.8 min-1 for recycle rate of 4.32 and 4.91 respectively. Carbon dioxide selectivity was decreased for both catalyst as it was converting to carbon monoxide. Carbon dioxide consumption was increased from 0.014 to 0.034 mole fraction. This concluded that CO2is being used in the system and

  19. Europa's Great Lakes

    Science.gov (United States)

    Schmidt, B. E.; Blankenship, D. D.; Patterson, G. W.; Schenk, P. M.

    2012-04-01

    Unique to the surface of Europa, chaos terrain is diagnostic of the properties and dynamics of its icy shell. While models have suggested that partial melt within a thick shell or melt-through of a thin shell may form chaos, neither model has been able to definitively explain all observations of chaos terrain. However, we present a new model that suggests large melt lenses form within the shell and that water-ice interactions above and within these lenses drive the production of chaos. Our analysis of the geomorphology of Conamara Chaos and Thera Macula, was used to infer and test a four-stage lens-collapse chaos formation model: 1) Thermal plumes of warm, pure ice ascend through the shell melting the impure brittle ice above, producing a lake of briny water and surface down draw due to volume reduction. 2) Surface deflection and driving force from the plume below hydraulically seals the water in place. 3) Extension of the brittle ice lid generates fractures from below, allowing brines to enter and fluidize the ice matrix. 4) As the lens and now brash matrix refreeze, thermal expansion creates domes and raises the chaos feature above the background terrain. This new "lense-collapse" model indicates that chaos features form in the presence of a great deal of liquid water, and that large liquid water bodies exist within 3km of Europa's surface comparable in volume to the North American Great Lakes. The detection of shallow subsurface "lakes" implies that the ice shell is recycling rapidly and that Europa may be currently active. In this presentation, we will explore environments on Europa and their analogs on Earth, from collapsing Antarctic ice shelves to to subglacial volcanos in Iceland. I will present these new analyses, and describe how this new perspective informs the debate about Europa's habitability and future exploration.

  20. Ruthenium promotion of Co/SBA-15 catalysts for Fischer-Tropsch synthesis in slurry-phase reactors

    Institute of Scientific and Technical Information of China (English)

    Jocielys Jovelino Rodrigues; Gina Pecchi; Fabiano André Narciso Fernandes; Meiry Gláucia Freire Rodrigues

    2012-01-01

    The aim of this work was to evaluate the catalytic properties of a Ru promoted Co/SBA-15 catalyst for Fischer-Tropsch synthesis (FTS).The Ru promoted Co/SBA-15 catalyst was prepared by wet impregnation method and was characterized by X-ray diffraction,X-ray energy dispersion spectrophotometer,N2 adsorption-desorption,temperature-programmed reduction and transmission electron microscopy.The Fischer-Tropsch synthesis using the catalyst was carried out to evaluate the catalyst activity and its effect on FTS product distribution.The synthesis was carried out in a slurry reactor operating at 513 K,20 atm,CO ∶ H2 molar ratio of 1 ∶ 1.X-ray diffraction showed that the calcined cobalt catalyst did not modify the structure of SBA-15,proving that Co was present in the form of Co3O4 in the catalyst.The addition of cobalt in SBA-15 decreased the specific superficial area of the molecular sieve.Fischer-Tropsch synthesis activity and C5+ hydrocarbon selectivity increased with the addition of Ru.The increases in activity and selectivity were attributed to the increased number of active sites resulting from higher reducibility and the synergetic effect of Ru and Co.Ru/Co/SBA-15 catalysts showed moderate conversion (40%) and high selectivity towards the production of C5+ (80 wt%).

  1. Retracing Memories

    Science.gov (United States)

    Harrison, David L.

    2005-01-01

    There are plenty of paths to poetry but few are as accessible as retracing ones own memories. When students are asked to write about something they remember, they are given them the gift of choosing from events that are important enough to recall. They remember because what happened was funny or scary or embarrassing or heartbreaking or silly.…

  2. Memory consolidation

    NARCIS (Netherlands)

    Takashima, A.; Bakker, I.

    2016-01-01

    In order to make use of novel experiences and knowledge to guide our future behavior, we must keep large amounts of information accessible for retrieval. The memory system that stores this information needs to be flexible in order to rapidly incorporate incoming information, but also requires that

  3. Broadcast Memories

    Institute of Scientific and Technical Information of China (English)

    陈淑娴

    1995-01-01

    At the root of all memory is a communication among neurons,millions of neurons, passing signals to one another like the transistors in a computer. Transistors have to be linked by wires in order to communicate—but neurons,it now seems, are different. According to a recent study dnne at Stanford, neu-

  4. Concrete Memories

    DEFF Research Database (Denmark)

    Wiegand, Frauke Katharina

    2015-01-01

    This article traces the presence of Atlantikwall bunkers in amateur holiday snapshots and discusses the ambiguous role of the bunker site in visual cultural memory. Departing from my family’s private photo collection from twenty years of vacationing at the Danish West coast, the different mundane...

  5. Synthesis, Modeling and Exergy Analysis of Atmospheric Air Blown Biomass Gasification for Fischer-Tropsch Process

    Directory of Open Access Journals (Sweden)

    K. D. Panopoulos

    2009-12-01

    Full Text Available

    The main objective of the present work is to investigate the combination of an atmospheric and a pressurised air blown biomass gasifier towards Fischer-Tropsch (FT synthesis of second generation biofuels and co-production of power. The complete process was simulated in AspenPlusTM software including sub-models for the gasification, gas cleaning and conditioning as well as for the FT reactor. A sensitivity analysis on exergetic performance was performed mainly examining the recycling of FT-tail gas. For the base case of 80% FT CO conversion without any recirculation, the exergetic efficiency was found to be 34.3% with atmospheric gasification and 30.64% for pressurised gasification. Recirculation of the non-reacted CO, H2 as well as light gas products of the FT-reactor back to the atmospheric gasifier can increase the overall efficiency up to 48.1 %.

    • This paper is an updated version of a paper published in the ECOS'08 proceedings.

  6. Preserved adiposity in the Fischer 344 rat devoid of gut microbiota.

    Science.gov (United States)

    Swartz, Timothy D; Sakar, Yassine; Duca, Frank A; Covasa, Mihai

    2013-04-01

    The gut microbiota is implicated in host metabolism and energy regulation. Germ-free (GF) C57BL/6 mice display decreased adiposity, an effect associated with increased intestinal fasting-induced adipose factor (FIAF) and decreased hepatic lipogenesis. However, whether the altered metabolism observed in the absence of gut microbiota extends to other species, commonly used to examine energy metabolism, is unknown. Thus, we used the GF Fischer 344 rat to examine adiposity and associated alterations in intestinal nutrient chemoreceptors, gut peptide levels, and FIAF expression, as well as markers of hepatic and adipose lipogenesis and adipogenesis. We found that GF rats displayed similar body weights and adiposity relative to controls. GF state was associated with up-regulation of intestinal and hepatic FIAF, decreased expression of hepatic FAS, ACC-1, and SREBP, and increased pAMPK and pACC. However, GF rats displayed reduced adipocyte FIAF, increased lipogenic enzymes, and decreased pAMPK, accompanied by an increase in adipocyte size. These findings show that, despite increased intestinal FIAF and reduced hepatic lipogenesis, adiposity is preserved in the Fisher 344 GF rat, unlike the C57Bl/6J GF mouse, with a shift in increased adipocyte lipogenesis. This also demonstrates that adipose, rather than intestinal, FIAF may have a more prominent role in adiposity.

  7. In situ observation of self-assembled hydrocarbon Fischer-Tropsch products on a cobalt catalyst

    Science.gov (United States)

    Navarro, Violeta; van Spronsen, Matthijs A.; Frenken, Joost W. M.

    2016-10-01

    Fischer-Tropsch synthesis is a heterogeneous catalytic reaction that creates approximately 2% of the world's fuel. It involves the synthesis of linear hydrocarbon molecules from a gaseous mixture of carbon monoxide and hydrogen at high pressures (from a few to tens of bars) and high temperatures (200-350 °C). To gain further insight into the fundamental mechanisms of this industrial process, we have used a purpose-built scanning tunnelling microscope to monitor a cobalt model catalyst under reaction conditions. We show that, after 30 minutes of reaction, the terraces of the cobalt catalyst are covered by parallel arrays of stripes. We propose that the stripes are formed by the self-assembly of linear hydrocarbon product molecules. Surprisingly, the width of the stripes corresponds to molecules that are 14 or 15 carbon atoms long. We introduce a simple model that explains the accumulation of such long molecules by describing their monomer-by-monomer synthesis and explicitly accounting for their thermal desorption.

  8. Product distributions of Fischer-Tropsch synthesis over Co/AC catalyst

    Institute of Scientific and Technical Information of China (English)

    Weixin Qian; Haitao Zhang; Weiyong Ying; Dingye Fang

    2011-01-01

    The product distributions of Fischer-Tropsch synthesis over Co/AC catalyst are investigated under different reaction conditions in an integral fixed bed reactor.It is found that the product distributions deviate from the ASF distribution.The deviation from ASF distribution is analyzed by taking the readsorption of alkenes and the following secondary reaction into consideration.It is noted that the contents of alcohol,alkene and alkane decline with the increasing carbon number,showing a slighter declining tendency of alkanes than those of alkenes and alcohols.It is also found that high temperature,space velocity,H2/CO in feed gas and low pressure are preferential for light hydrocarbons and alcohols while against the chain propagation.The effect of space velocity on the product distributions especially on the light products is not obvious.It is noticed that low temperature,space velocity,H2/CO and high pressure lead to high contents of alcohols; high temperature,H2/CO and low space velocity lead to high contents of alkanes.The effect of pressure on the amounts of alkanes is not significant; high space velocity and low temperature,pressure,H2/CO are preferential for alkenes.

  9. Nanocrystalline Iron-Ore-Based Catalysts for Fischer-Tropsch Synthesis.

    Science.gov (United States)

    Yong, Seok; Park, Ji Chan; Lee, Ho-Tae; Yang, Jung-Il; Hong, SungJun; Jung, Heon; Chun, Dong Hyun

    2016-02-01

    Nanocrystalline iron ore particles were fabricated by a wet-milling process using an Ultra Apex Mill, after which they were used as raw materials of iron-based catalysts for low-temperature Fischer-Tropsch synthesis (FTS) below 280 degrees C, which usually requires catalysts with a high surface area, a large pore volume, and a small crystallite size. The wet-milling process using the Ultra Apex Mill effectively destroyed the initial crystallite structure of the natural iron ores of several tens to hundreds of nanometers in size, resulting in the generation of nanocrystalline iron ore particles with a high surface area and a large pore volume. The iron-ore-based catalysts prepared from the nanocrystalline iron ore particles effectively catalyzed the low-temperature FTS, displaying a high CO conversion (about 90%) and good C5+ hydrocarbon productivity (about 0.22 g/g(cat)(-h)). This demonstrates the feasibility of using the iron-ore-based catalysts as inexpensive and disposable catalysts for the low-temperature FTS.

  10. SEPARATION OF FISCHER-TROPSCH WAX FROM CATALYST BY SUPERCRITICAL EXTRACTION

    Energy Technology Data Exchange (ETDEWEB)

    MARK C. THIES; PATRICK C. JOYCE

    1998-10-31

    The objective of this research project is to evaluate the potential of supercritical fluid (SCF) extraction for the recovery and fractionation of the wax product from the slurry bubble column (SBC) reactor of the Fischer-Tropsch (F-T) process. The wax, comprised mostly of branched and linear alkanes with a broad molecular weight distribution up to C{sub 100}, will be extracted with a hydrocarbon solvent that has a critical temperature near the operating temperature of the SBC reactor, i.e., 200-300 C. Initial work is being performed using n-hexane as the solvent. The success of the project depends on two factors. First, the supercritical solvent must be able to dissolve the F-T wax; furthermore, this must be accomplished at conditions that do not entrain the solid catalyst. Second, the extraction must be controlled so as not to favor the removal of the low molecular weight wax compounds. That is, a constant carbon-number distribution in the wax slurry must be maintained at steady-state column operation. Three major tasks are being undertaken to evaluate our proposed SCF extraction process. Task 1: Equilibrium solubility measurements for model F-T wax components in supercritical fluids at conditions representative of those in a SBC reactor. Task 2: Thermodynamic modeling of the measured VLE data for extending our results to real wax systems. Task 3: Process design studies of our proposed process. Additional details of the task structure are given.

  11. SEPARATION OF FISCHER-TROPSCH WAX FROM CATALYST BY SUPERCRITICAL EXTRACTION

    Energy Technology Data Exchange (ETDEWEB)

    Patrick C. Joyce; Mark C. Thies

    1999-03-31

    The objective of this research project was to evaluate the potential of supercritical fluid (SCF) extraction for the recovery and fractionation of the wax product from the slurry bubble column (SBC) reactor of the Fischer-Tropsch (F-T) process. The wax, comprised mostly of branched and linear alkanes with a broad molecular weight distribution up to C{sub 100}, is to be extracted with a hydrocarbon solvent that has a critical temperature near the operating temperature of the SBC reactor, i.e., 200-300 C. Aspen Plus{trademark} was used to perform process simulation studies on the proposed extraction process, with Redlich-Kwong-Soave (RKS) being used for the thermodynamic property model. In summary, we have made comprehensive VLE measurements for short alkane + long alkane systems over a wide range of pressures and temperatures, dramatically increasing the amount of high-quality data available for these simple, yet highly relevant systems. In addition, our work has demonstrated that, surprisingly, no current thermodynamic model can adequately predict VLE behavior for these systems. Thus, process simulations (such as those for our proposed SCF extraction process) that incorporate these systems can currently only give results that are qualitative at best. Although significant progress has been made in the past decade, more experimental and theoretical work remain to be done before the phase equilibria of asymmetric alkane mixtures can be predicted with confidence.

  12. Baseline design/economics for advanced Fischer-Tropsch technology. Quarterly report, January--March 1992

    Energy Technology Data Exchange (ETDEWEB)

    1992-09-01

    The objectives of the study are to: Develop a baseline design for indirect liquefaction using advanced Fischer-Tropsch (F-T) technology. Prepare the capital and operating costs for the baseline design. Develop a process flow sheet simulation (PFS) model. This report summarizes the activities completed during the period December 23, 1992 through March 15, 1992. In Task 1, Baseline Design and Alternates, the following activities related to the tradeoff studies were completed: approach and basis; oxygen purity; F-T reactor pressure; wax yield; autothermal reformer; hydrocarbons (C{sub 3}/C{sub 4}s) recovery; and hydrogenrecovery. In Task 3, Engineering Design Criteria, activities were initiated to support the process tradeoff studies in Task I and to develop the environmental strategy for the Illinois site. The work completed to date consists of the development of the F-T reactor yield correlation from the Mobil dam and a brief review of the environmental strategy prepared for the same site in the direct liquefaction baseline study.Some work has also been done in establishing site-related criteria, in establishing the maximum vessel diameter for train sizing and in coping with the low H{sub 2}/CO ratio from the Shell gasifier. In Task 7, Project Management and Administration, the following activities were completed: the subcontract agreement between Amoco and Bechtel was negotiated; a first technical progress meeting was held at the Bechtel office in February; and the final Project Management Plan was approved by PETC and issued in March 1992.

  13. Effect of Manganese Incorporation Manner on an Iron-Based Catalyst for Fischer-Tropsch Synthesis

    Institute of Scientific and Technical Information of China (English)

    Tingzhen Li; Yong Yang; Chenghua Zhang; Zhichao Tao; Haijun Wan; Xia An; Hongwei Xiang; Yongwang Li

    2007-01-01

    A systematic study was undertaken to investigate the effects of the manganese incorporation manner on the textural properties,bulk and surface phase compositions,reduction/carburization behaviors,and surface basicity of an iron-based Fischer-Tropsch synthesis (FTS) catalyst.The catalyst samples were characterized by N2 Physisorption,X-ray photoelectron spectroscopy(XPS),H2(or CO) temperature-programmed reduction(TPR),CO2 temperature-programmed desorption(TPD),and Mossbauer spectroscopy.The FTS performance of the catalysts was studied in a slurry-phase continuously stirred tank reactor(CSTR).The characterization results indicated that the manganese promoter incor-porated by using the coprecipitation method could improve the dispersion of iron oxide,and decrease the size of the iron oxide crystallite.The manganese incorporated with the impregnation method is enriched on the catalyst's surface.The manganese promoter added with the impregnation method suppresses the reduction and carburization of the catalyst in H2,CO,and syngas because of the excessive enrichment of manganese on the catalyst surface.The catalyst added manganese using the coprecipitation method has the highest CO conversion (51.9%) and the lowest selectivity for heavy hydrocarbons(C12+).

  14. Emissions from Road Vehicles Fuelled by Fischer Tropsch Based Diesel and Gasoline

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, U.; Lundorf, P.; Ivarsson, A.; Schramm, J. [Technical University of Denmark (Denmark); Rehnlund, B. [Atrax Energi AB (Sweden); Blinge, M. [The Swedish Transport Institute (Sweden)

    2006-11-15

    The described results were carried out under the umbrella of IEA Advanced Motor Fuels Agreement. The purpose was to evaluate the emissions of carbon monoxide (CO), unburned hydrocarbons (HC), nitrogen oxides (NOx), particulate matter (PM) and polycyclic aromatic hydrocarbons (PAH) from vehicles fuelled by Fischer Tropsch (FT) based diesel and gasoline fuel, compared to the emissions from ordinary diesel and gasoline. The comparison for diesel fuels was based on a literature review, whereas the gasoline comparison had to be based on our own experiments, since almost no references were found in this field. In this context measurement according to the Federal Test Procedure (FTP) and the New European Driving Cycle (NEDC) were carried out on a chassis dynamometer with a directly injected gasoline vehicle. Experiments were carried out with a reference fuel, a fuel based 70% on FT and an alkylate fuel (Aspen), which was supposed to be very similar, in many ways, to FT fuel. FT based diesel generally showed good emission performance, whereas the FT based gasoline not necessary lead to lower emissions. On the other hand, the Aspen fuel did show many advantages for the emissions from the gasoline vehicle.

  15. Emissions from Road Vehicles Fuelled by Fischer Tropsch Based Diesel and Gasoline

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, U.; Lundorf, P.; Ivarsson, A.; Schramm, J. [Technical University of Denmark (Denmark); Rehnlund, B. [Atrax Energi AB (Sweden); Blinge, M. [The Swedish Transport Institute (Sweden)

    2006-11-15

    The described results were carried out under the umbrella of IEA Advanced Motor Fuels Agreement. The purpose was to evaluate the emissions of carbon monoxide (CO), unburned hydrocarbons (HC), nitrogen oxides (NOx), particulate matter (PM) and polycyclic aromatic hydrocarbons (PAH) from vehicles fuelled by Fischer Tropsch (FT) based diesel and gasoline fuel, compared to the emissions from ordinary diesel and gasoline. The comparison for diesel fuels was based on a literature review, whereas the gasoline comparison had to be based on our own experiments, since almost no references were found in this field. In this context measurement according to the Federal Test Procedure (FTP) and the New European Driving Cycle (NEDC) were carried out on a chassis dynamometer with a directly injected gasoline vehicle. Experiments were carried out with a reference fuel, a fuel based 70% on FT and an alkylate fuel (Aspen), which was supposed to be very similar, in many ways, to FT fuel. FT based diesel generally showed good emission performance, whereas the FT based gasoline not necessary lead to lower emissions. On the other hand, the Aspen fuel did show many advantages for the emissions from the gasoline vehicle.

  16. On the origin of the cobalt particle size effects in Fischer-Tropsch catalysis.

    Science.gov (United States)

    den Breejen, J P; Radstake, P B; Bezemer, G L; Bitter, J H; Frøseth, V; Holmen, A; de Jong, K P

    2009-05-27

    The effects of metal particle size in catalysis are of prime scientific and industrial importance and call for a better understanding. In this paper the origin of the cobalt particle size effects in Fischer-Tropsch (FT) catalysis was studied. Steady-State Isotopic Transient Kinetic Analysis (SSITKA) was applied to provide surface residence times and coverages of reaction intermediates as a function of Co particle size (2.6-16 nm). For carbon nanofiber supported cobalt catalysts at 210 degrees C and H(2)/CO = 10 v/v, it appeared that the surface residence times of reversibly bonded CH(x) and OH(x) intermediates increased, whereas that of CO decreased for small (particles. A higher coverage of irreversibly bonded CO was found for small Co particles that was ascribed to a larger fraction of low-coordinated surface sites. The coverages and residence times obtained from SSITKA were used to describe the surface-specific activity (TOF) quantitatively and the CH(4) selectivity qualitatively as a function of Co particle size for the FT reaction (220 degrees C, H(2)/CO = 2). The lower TOF of Co particles particles is mainly brought about by their higher hydrogen coverages.

  17. Effect of niobium promoter on iron-based catalyst for Fischer-Tropsch reaction

    Institute of Scientific and Technical Information of China (English)

    Sardar ALI; Noor Asmawati MOHD ZABIDI; Duvvuri SUBBARAO

    2012-01-01

    Niobium-promoted Fe/CNTs catalysts were prepared using a wet impregnation method.Samples were characterized by nitrogen adsorption,H2-TPR,TPD,XRD and TEM.The Fischer-Tropsch Synthesis (FTS) was carried out in a fixed-bed microreactor at 220 ℃,1 atm and H2/CO =2 for 5 h.Addition of niobium into Fe/CNTs increased the dispersion,decreased the average size of iron oxide nanoparticles and the catalyst reducibility.Niobium-promoted Fe catalyst resulted in appreciable increase in the selectivity of C5+ hydrocarbons and suppressed methane formation.These effects were more pronounced for the 0.04% Nb/Fe/CNTs catalyst,compared to those observed from other niobium compositions.The 0.04% Nb/Fe/CNTs catalyst enhanced the C5+ hydrocarbons selectivity by a factor of 67.5% and reduced the methane selectivity by a factor of 59.2%.

  18. Influence of Reduction Promoters on Stability of Cobalt/g-Alumina Fischer-Tropsch Synthesis Catalysts

    Directory of Open Access Journals (Sweden)

    Gary Jacobs

    2014-03-01

    Full Text Available This focused review article underscores how metal reduction promoters can impact deactivation phenomena associated with cobalt Fischer-Tropsch synthesis catalysts. Promoters can exacerbate sintering if the additional cobalt metal clusters, formed as a result of the promoting effect, are in close proximity at the nanoscale to other cobalt particles on the surface. Recent efforts have shown that when promoters are used to facilitate the reduction of small crystallites with the aim of increasing surface Co0 site densities (e.g., in research catalysts, ultra-small crystallites (e.g., <2–4.4 nm formed are more susceptible to oxidation at high conversion relative to larger ones. The choice of promoter is important, as certain metals (e.g., Au that promote cobalt oxide reduction can separate from cobalt during oxidation-reduction (regeneration cycles. Finally, some elements have been identified to promote reduction but either poison the surface of Co0 (e.g., Cu, or produce excessive light gas selectivity (e.g., Cu and Pd, or Au at high loading. Computational studies indicate that certain promoters may inhibit polymeric C formation by hindering C-C coupling.

  19. Baseline design/economics for advanced Fischer-Tropsch technology. Quarterly report, April--June 1992

    Energy Technology Data Exchange (ETDEWEB)

    1992-10-01

    Effective September 26, 1991, Bechtel, with Amoco as the main subcontractor, initiated a study to develop a computer model and baseline design for advanced Fischer-Tropsch (F-T) technology for the US Department of Energy`s Pittsburgh Energy Technology Center (PETC). The objectives of the study are to: Develop a baseline design for indirect liquefaction using advanced F-T technology; prepare the capital and operating costs for the baseline design; and develop a process flow sheet simulation (PI-S) model. The baseline design, the economic analysis, and the computer model win be the major research planning tools that PETC will use to plan, guide, and evaluate its ongoing and future research and commercialization programs relating to indirect coal liquefaction. for the manufacture of synthetic liquid fuels from coal. This report is Bechtel`s third quarterly technical progress report covering the period from March 16, 1992 through June 21, 1992. This report consists of seven sections: Section 1 - introduction; Section 2 - summary; Section 3 - carbon dioxide removal tradeoff study; Section 4 - preliminary plant designs for coal preparation; Section 5 - preliminary design for syngas production; Section 6 - Task 3 - engineering design criteria; and Section 7 - project management.

  20. Effects of Fischer-Tropsch diesel fuel on combustion and emissions of direct injection diesel engine

    Institute of Scientific and Technical Information of China (English)

    Yongcheng HUANG; Shangxue WANG; Longbao ZHOU

    2008-01-01

    Effects of Fischer-Tropsch (F-T) diesel fuel on the combustion and emission characteristics of a single-cylinder direct injection diesel engine under different fuel delivery advance angles were investigated. The experi-mental results show that F-T diesel fuel exhibits shorter ignition delay, lower peak values of premixed burning rate, lower combustion pressure and pressure rise rate, and higher peak value of diffusion burning rate than con-ventional diesel fuel when the engine remains unmodified. In addition, the unmodified engine with F-T diesel fuel has lower brake specific fuel consumption and higher effective thermal efficiency, and presents lower HC, CO, NOx and smoke emissions than conventional diesel fuel. When fuel delivery advance angle is retarded by 3 crank angle degrees, the combustion duration is obviously shor-tened; the peak values of premixed burning rate, the com-bustion pressure and pressure rise rate are further reduced; and the peak value of diffusion burning rate is further increased for F-T diesel fuel operation, Moreover, the retardation of fuel delivery advance angle results in a further significant reduction in NOx emissions with no penalty on specific fuel consumption and with much less penalty on HC, CO and smoke emissions.

  1. Combustion characteristics of a direct-injection diesel engine fueled with Fischer-Tropsch diesel

    Institute of Scientific and Technical Information of China (English)

    HUANG Yongcheng; ZHOU Longbao; PAN Keyu

    2007-01-01

    Fischer-Tropsch (F-T) diesel fuel is characterized by a high cetane number, a near-zero sulphur content and a very low aromatic level. On the basis of the recorded incylinder pressures and injector needle lifts, the combustion characteristics of an unmodified single-cylinder directinjection diesel engine operating on F-T diesel fuel are analyzed and compared with those of conventional diesel fuel operation. The results show that F-T diesel fuel exhibits a slightly longer injection delay and injection duration, an average of 18.7% shorter ignition delay, and a comparable total combustion duration when compared to those of conventional diesel fuel. Meanwhile, F-T diesel fuel displays an average of 26.8% lower peak value of premixed burning rate and a higher peak value of diffusive burning rate. In addition, the F-T diesel engine has a slightly lower peak combustion pressure, a far lower rate of pressure rise, and a lower mechanical load and combustion noise than the conventional diesel engine. The brake specific fuel consumption is lower and the effective thermal efficiency is higher for F-T diesel fuel operation.

  2. Pyrolysis-GCMS Analysis of Solid Organic Products from Catalytic Fischer-Tropsch Synthesis Experiments

    Science.gov (United States)

    Locke, Darren R.; Yazzie, Cyriah A.; Burton, Aaron S.; Niles, Paul B.; Johnson, Natasha M.

    2015-01-01

    Abiotic synthesis of complex organic compounds in the early solar nebula that formed our solar system is hypothesized to occur via a Fischer-Tropsch type (FTT) synthesis involving the reaction of hydrogen and carbon monoxide gases over metal and metal oxide catalysts. In general, at low temperatures (less than 200 C), FTT synthesis is expected to form abundant alkane compounds while at higher temperatures (greater than 200 C) it is expected to product lesser amounts of n-alkanes and greater amounts of alkene, alcohol, and polycyclic aromatic hydrocarbons (PAHs). Experiments utilizing a closed-gas circulation system to study the effects of FTT reaction temperature, catalysts, and number of experimental cycles on the resulting solid insoluble organic products are being performed in the laboratory at NASA Goddard Space Flight Center. These experiments aim to determine whether or not FTT reactions on grain surfaces in the protosolar nebula could be the source of the insoluble organic matter observed in meteorites. The resulting solid organic products are being analyzed at NASA Johnson Space Center by pyrolysis gas chromatography mass spectrometry (PY-GCMS). PY-GCMS yields the types and distribution of organic compounds released from the insoluble organic matter generated from the FTT reactions. Previously, exploratory work utilizing PY-GCMS to characterize the deposited organic materials from these reactions has been reported. Presented here are new organic analyses using magnetite catalyst to produce solid insoluble organic FTT products with varying reaction temperatures and number of experimental cycles.

  3. Structural equation modeling identifies markers of damage and function in the aging male Fischer 344 rat.

    Science.gov (United States)

    Grunz-Borgmann, Elizabeth A; Nichols, LaNita A; Wiedmeyer, Charles E; Spagnoli, Sean; Trzeciakowski, Jerome P; Parrish, Alan R

    2016-06-01

    The male Fischer 344 rat is an established model to study progressive renal dysfunction that is similar, but not identical, to chronic kidney disease (CKD) in humans. These studies were designed to assess age-dependent alterations in renal structure and function at late-life timepoints, 16-24 months. Elevations in BUN and plasma creatinine were not significant until 24 months, however, elevations in the more sensitive markers of function, plasma cystatin C and proteinuria, were detectable at 16 and 18 months, respectively. Interestingly, cystatin C levels were not corrected by caloric restriction. Urinary Kim-1, a marker of CKD, was elevated as early as 16 months. Klotho gene expression was significantly decreased at 24 months, but not at earlier timepoints. Alterations in renal structure, glomerulosclerosis and tubulointerstitial fibrosis, were noted at 16 months, with little change from 18 to 24 months. Tubulointerstitial inflammation was increased at 16 months, and remained similar from 18 to 24 months. A SEM (structural equation modeling) model of age-related renal dysfunction suggests that proteinuria is a marker of renal damage, while urinary Kim-1 is a marker of both damage and function. Taken together, these results demonstrate that age-dependent nephropathy begins as early as 16 months and progresses rapidly over the next 8 months.

  4. Small-Scale Coal-Biomass to Liquids Production Using Highly Selective Fischer-Tropsch Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Gangwal, Santosh K. [Southern Research Institute, Durham, NC (United States); McCabe, Kevin [Southern Research Institute, Durham, NC (United States)

    2015-04-30

    The research project advanced coal-to-liquids (CTL) and coal-biomass to liquids (CBTL) processes by testing and validating Chevron’s highly selective and active cobalt-zeolite hybrid Fischer-Tropsch (FT) catalyst to convert gasifier syngas predominantly to gasoline, jet fuel and diesel range hydrocarbon liquids, thereby eliminating expensive wax upgrading operations The National Carbon Capture Center (NCCC) operated by Southern Company (SC) at Wilsonville, Alabama served as the host site for the gasifier slip-stream testing/demonstration. Southern Research designed, installed and commissioned a bench scale skid mounted FT reactor system (SR-CBTL test rig) that was fully integrated with a slip stream from SC/NCCC’s transport integrated gasifier (TRIGTM). The test-rig was designed to receive up to 5 lb/h raw syngas augmented with bottled syngas to adjust the H2/CO molar ratio to 2, clean it to cobalt FT catalyst specifications, and produce liquid FT products at the design capacity of 2 to 4 L/day. It employed a 2-inch diameter boiling water jacketed fixed-bed heat-exchange FT reactor incorporating Chevron’s catalyst in Intramicron’s high thermal conductivity micro-fibrous entrapped catalyst (MFEC) packing to efficiently remove heat produced by the highly exothermic FT reaction.

  5. Influence of liquid medium on the activity of a low-alpha Fischer-Tropsch catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Gormley, R.J.; Zarochak, M.F.; Deffenbaugh, P.W.; Rao, K.R.P.M.

    1995-12-31

    The purpose of this research was to measure activity, selectivity, and the maintenance of these properties in slurry autoclave experiments with a Fischer-Tropsch (FT) catalyst that was used in the {open_quotes}FT II{close_quotes} bubble-column test, conducted at the Alternative Fuels Development Unit (AFDU) at LaPorte, Texas during May 1994. The catalyst contained iron, copper, and potassium and was formulated to produce mainly hydrocarbons in the gasoline range with lesser production of diesel-range products and wax. The probability of chain growth was thus deliberately kept low. Principal goals of the autoclave work have been to find the true activity of this catalyst in a stirred tank reactor, unhindered by heat or mass transfer effects, and to obtain a steady conversion and selectivity over the approximately 15 days of each test. Slurry autoclave testing of the catalyst in heavier waxes also allows insight into operation of larger slurry bubble column reactors. The stability of reactor operation in these experiments, particularly at loadings exceeding 20 weight %, suggests the likely stability of operations on a larger scale.

  6. Effects of pentosan polysulfate sodium on the estrogen-induced pituitary prolactinoma in Fischer 344 rats.

    Science.gov (United States)

    Mucha, Slawomir; Melen-Mucha, Gabriela; Stepien, Tomasz; Godlewski, Andrzej; Stepien, Henryk

    2002-01-01

    The development of estrogen-induced pituitary prolactinoma in Fischer 344 (F344) rats is associated with enhanced neovascularization. This type of tumor is a rich source of basic fibroblast growth factor (bFGF), which possesses strong mitogenic and angiogenic properties. Pentosan polysulfate sodium (PPS) has been shown to exert antitumor activity by antagonizing the binding of bFGF to cell surface receptors. We have examined the effects of pentosan on tumor growth, hyperprolactinemia and angiogenesis in diethylstilbestrol-induced anterior pituitary adenoma in F344 rats. Chronic treatment with PPS did not cause any changes in the pituitary weight and serum prolactin concentration in comparison with untreated animals. The density of microvessels identified by CD-31 was also not affected by the tested drug. On the other hand, pentosan has been found to decrease cell proliferation evaluated by a number of PCNA-positive stained cell nuclei. Moreover, the TUNEL method has revealed an increased number of apoptotic bodies within the anterior pituitary after treatment with PPS. Despite the antiproliferative and proapoptotic activity of pentosan, the drug failed to inhibit tumor growth. This fact might be due to the lack of antiangiogenic activity of PPS in this experimental design.

  7. Biosyngas Fischer. Tropsch conversion by high Fe loaded supported catalysts prepared with ultrasound and microwave

    Energy Technology Data Exchange (ETDEWEB)

    Pirola, C.; Di Fronzo, A.; Boffito, D.C.; Bianchi, C. [Milano Univ. (Italy). Dipt. di Chimica; Di Michele, A. [Perugia Univ. (Italy). Dipt. di Fisica

    2012-07-01

    Catalysts with iron high loading of 30 wt%, promoted with K (2.0 wt%) and Cu (3.75 wt%), have been synthesized according to three different methods: (1) the traditional impregnation method (TR); (2) Ultrasound (US) assisted TR method; (3) Microwave (MW) assisted TR method. All the samples have been fully characterized by BET, ICP/OES, XRPD, TG-DTA, FT-IR, TPR, SEM and TEM and tested in a laboratory pilot plant for Fischer-Tropsch synthesis working at 220 C and 20 bar. The results of the catalysts characterization indicated that the morphology of the samples strongly depends on the method of preparation. The best FTS results in term of C{sub 2+} yield (41%) has been obtained using MW with a good value of the selectivity towards heavy hydrocarbons, while in term of CO conversion (58%), using US. The samples prepared with non-traditional methods show FTS better results, probably due to a more wide and uniform distribution of Fe in the medium during the synthesis phase. (orig.)

  8. Fischer-Tropsch reaction on a thermally conductive and reusable silicon carbide support.

    Science.gov (United States)

    Liu, Yuefeng; Ersen, Ovidiu; Meny, Christian; Luck, Francis; Pham-Huu, Cuong

    2014-05-01

    The Fischer-Tropsch (FT) process, in which synthesis gas (syngas) derived from coal, natural gas, and biomass is converted into synthetic liquid fuels and chemicals, is a strongly exothermic reaction, and thus, a large amount of heat is generated during the reaction that could severely modify the overall selectivity of the process. In this Review, we report the advantages that can be offered by different thermally conductive supports, that is, carbon nanomaterials and silicon carbide, pure or doped with different promoters, for the development of more active and selective FT catalysts. This Review follows a discussion regarding the clear trend in the advantages and drawbacks of these systems in terms of energy efficiency and catalytic performance for this most-demanded catalytic process. It is demonstrated that the use of a support with an appropriate pore size and thermal conductivity is an effective strategy to tune and improve the activity of the catalyst and to improve product selectivity in the FT process. The active phase and the recovery of the support, which also represents a main concern in terms of the large amount of FT catalyst used and the cost of the active cobalt phase, is also discussed within the framework of this Review. It is expected that a thermally conductive support such as β-SiC will not only improve the development of the FT process, but that it will also be part of a new support for different catalytic processes for which high catalytic performance and selectivity are strongly needed.

  9. Body protein status in Fischer 344 rats bearing the MCA sarcoma

    Energy Technology Data Exchange (ETDEWEB)

    Radcliffe, J.D.

    1986-03-05

    The effect of a methylcholanthrene (MCA) sarcoma on the protein status of adult, male, Fischer-344 rats was investigated. Three groups of ten rats were used. One group (TB) was inoculated with MCA sarcoma tissue, control (C) and pair-fed (PF) groups received saline only. Rats were fed a purified (20% casein, 20% fat, 45% sucrose) diet from day 7 post-transplant, when tumors became palpable. Food intake of TB was depressed relative to C at day 15 PT. Animals were killed at day 22 PT. In comparison to C, tumor growth was associated with a decrease in gastrocnemius muscle protein content and an increase in spleen weight and protein content. There was no effect of tumor growth on the weight or protein content of liver, heart, or kidneys. Data from PF animals suggested that decreased gastrocnemius muscle protein content was partly attributable to decreased food intake and partly to tumor growth; the increased spleen protein was due to tumor growth per se. Thus, growth of the MCA sarcoma affects host protein status. Some of these effects are caused partly by hypophagia and partly by tumor growth and others are due to tumor growth per se.

  10. Electrochemical determination of water in environmental hydraulic fluids using the karl Fischer reaction.

    Science.gov (United States)

    Cedergren, A; Lundström, M

    1997-10-01

    Different procedures based on the Karl Fischer reaction were investigated with respect to their applicability for water determinations in environmental hydraulic fluids:  (i) continuous coulometry using a recently described diaphragm-free cell; (ii) on-line stripping of water at elevated temperature using either continuous coulometry or direct potentiometry for detection of the liberated water. Except for one of the oils, Statoil PA, which is a poly(α-olefin) with certain polymers added, no significant difference was found among coulometry using an optimized imidazole-buffered methanolic reagent containing 75% (v/v) chloroform, the two different stripping techniques (working in the temperature interval 100-110 °C), and the commercially available Hydranal Coulomat AG-H. The high stability and sensitivity of the coulometric technique described made it possible to work with sample amounts in the low milligram-range, and this is shown to increase the reliability of the coulometric method as compared to normally used procedures.

  11. Progress in pulsed-current Karl Fischer coulometry using diaphragm-free cells.

    Science.gov (United States)

    Nordmark, U; Cedergren, A

    2000-07-01

    Factors influencing the accuracy of water determinations using diaphragm-free, pulsed current Karl Fischer (KF) coulometry were investigated with the new Metrohm 756 instrument. Results obtained with commercially available reagents from Riedel-deHaen and Merck were compared with home-made ones that were especially designed to minimize the formation of iodine-consuming reduction products generated in the cathode reaction. Positive errors in the range 2-5% were found for the commercial reagents as compared to 0.2-1% for the home-made ones which were buffered at about pH 10 containing modifiers like chloroform, hexanol or ethylene glycol. Except for the composition of the KF-reagent, the cathode current density and the titration rate were found to be critical parameters for the accuracy of the determinations. For all reagents investigated, the best results were obtained for the maximum generator current 400 mA (corresponding to a current density of 1,400 mA cm(-2)) in combination with a maximum titration rate of 2,000 microg min(-1). Surprisingly, the errors found under optimum conditions for the pulse technique were always somewhat larger than the corresponding values obtained with continuous coulometry.

  12. The role of mitochondrial DNA large deletion for the development of presbycusis in Fischer 344 rats.

    Science.gov (United States)

    Yin, Shankai; Yu, Zhiping; Sockalingam, Ravi; Bance, Manohar; Sun, Genlou; Wang, Jian

    2007-09-01

    Age-related hearing loss, or presbycusis, has been associated with large-scale mitochondrial DNA (mtDNA) deletion in previous studies. However, the role of this mtDNA damage in presbycusis is still not clear because the deletion in inner ears has not been measured quantitatively and analyzed in parallel with the time course of presbycusis. In the present study, the deletion was quantified using quantitative real-time PCR (qRT-PCR) in male Fischer 344 rats of different ages. It was found that the deletion increased quickly during young adulthood and reached over 60% at 6 months of age. However, a significant hearing loss was not seen until after 12 months of age. The results suggest that the existence of the deletion per se does not necessarily imply cochlear damage, but rather a critical level of the accumulated deletion seems to precede the hearing loss. The long delay may indicate the involvement of mechanisms other than mtDNA deletion in the development of presbycusis.

  13. Differences in performance between Sprague-Dawley and Fischer 344 rats in positive reinforcement tasks.

    Science.gov (United States)

    Rodriguez, Jesse S; Boctor, Sherin Y; Phelix, Clyde F; Martinez, Joe L

    2008-03-01

    This experimental investigation tested two different strains of rat, Sprague-Dawley (SD) and Fischer 344 (F344), in their ability to learn lever pressing for food (autoshaping) or intracranial self-administration (ICSA) of dextroamphetamine (AMPH) into the nucleus accumbens (NAcc). Additionally, a unique method of intracranial drug delivery was utilized, via reverse dialysis, by the use of a microdiaylsis probe. The experiments revealed definite behavioral differences between SD and F344 animals. The autoshaping data indicated that SD rats, on average, acquired lever pressing for food in fewer training days than F344 rats. Also, the ICSA experiment revealed that SD rats self-administered AMPH at a 30 mug/mul concentration. Lever pressing was significantly greater in those SD rats receiving AMPH than in the F344 drug group. Furthermore, the F344 rats never acquired lever pressing for intra-NAcc delivery of AMPH under our testing regime. These data reveal differences in performance of positively reinforced operant tasks between the inbred F344 rats as compared to the outbred SD strain.

  14. Age-related changes in mitochondrial function and antioxidative enzyme activity in fischer 344 rats.

    Science.gov (United States)

    Meng, Qingying; Wong, Yee Ting; Chen, Jie; Ruan, Runsheng

    2007-03-01

    We have previously reported the changes of mitochondrial function and/or antioxidative enzyme efficiency in a few organs of rats as a result of aging. However, there is a further need to reach a conclusion about their interactions in biological functions based on other evaluation tips like the usage of advanced methods and the exploring of crucial biochemical parameters. Therefore, we investigated the mitochondrial inner membrane functional integrity by the analysis of respiration control ratio and membrane potential in the liver and brain of young (8 months) and old (26 months) Fischer 344 rats. The disintegration of mitochondrial membrane integrity was determined higher in the liver of old rats than that of young rats. This was well correlated with the decrease of total superoxide dismutase (SOD), Cu/Zn-SOD, Mn-SOD and glutathione peroxidase activities in most of the organs, except for the increase of catalase activity in heart of old rats. Similarly, the protein expressions of these enzymes were down regulated in the liver and kidney of old rats. Taken together, we suggest that the mitochondrial malfunction in old rats is associated with the decrease of antioxidative enzyme efficiency. And the data are also discussed with changes in the results from inter-laboratories.

  15. Nanosized cobalt-based catalyst prepared by supercritical phase condition for Fischer-Tropsch synthesis

    Institute of Scientific and Technical Information of China (English)

    Jingmiao Li; Jingchang Zhang; Runduo Zhang; Weiliang Cao

    2009-01-01

    A series of nanosized Co/Zn/Mn/K composite catalysts for Fischer-Tropsch synthesis (FTS) were prepared by supercritical fluid drying (SCFD) method and common drying (CD) method. The nanosized cobalt-based catalysts were characterized by XRD,TEM and BET techniques. Their catalytic performances were tested in a slurry-bed reactor under FTS reaction conditions. The drying and crystallization were carded out simultaneously during SCFD,therefore,the catalysts prepared by SCFD method have ideal structure and show the FTS performance superior to the others prepared by CD method. The FTS activity and selectivity were improved via adding Zn,Mn and K promoters,and less CH_4 and CO_2 as well as higher yield of C~(5+) products were achieved. The optimal performance of a 92% CO conversion and a 65% C~(5+) product yield was obtained over a catalyst with the component of Co/Zn/Mn/K = 100/50/10/7. Furthermore,the catalytic performance was studied under the conditions of liquid-phase and supercriticai phase slurry-bed,and C~(5+) product yield were 57.4% and 65.4%,respectively. In summary,better catalytic performance was obtained using the nanosized catalyst prepared by SCFD method under supercritical reaction conditions,resulting in higher conversion of CO,less CO_2 byproduct,and higher yield of C~(5+) products,

  16. A New Method To Convert the Fischer Projection of a Monosaccharide to the Haworth Projection

    Science.gov (United States)

    Zhang, Qing-Zhi; Zhang, Shen-Song

    1999-06-01

    This method is based upon the R,S-configuration designation of each asymmetric carbon of a monosaccharide. According to the rule of configurational retention of each original asymmetric carbon, the Fischer projection of a monosaccharide can be converted into different views of the Haworth projection (the carbon-numbering orientation of the Haworth ring can be in either a clockwise or a counterclockwise direction, and the oxygen atom can be written at any corner of the ring). The D,L-configuration of a sugar in Haworth projection can be directly determined by designating the R,S-configuration of the highest-numbered asymmetric carbon; that is, the most distant carbon from the anomeric carbon. The R-configuration at this carbon corresponds to the D-family, and S- to the L-family. By comparing the stereochemistry of the anomeric carbon with that of the highest-numbered asymmetric carbon, the a, b-anomer of a Haworth projection is directly notated. If these two carbons have the same configuration (R,R or S,S), the anomer is b; if different (R,S or S,R), the anomer is a. This method proves to be general and widely applicable.

  17. Fischer Plots of Wumishan Cyclothems, Precambrian Records of Third-Order Sea-Level Changes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The Mesoproterozoic Wumishan Formation ((1 310±20) Ma-(1 207±10) Ma) in Jixian, Tianjin represents a succession of 3 300 meter thick carbonate strata where are the best developed stromatolite biostromes and thrombolite bioherms. These biostromes and bioherms, together with tidal-flat dolomites and muddy dolostones, form Wumishan cyclothems with approximately symmetrical facies-succession fabrics, which belong to carbonate meter-scale cyclic sequences of peritidal type. These cyclothems are overlain by lagoon dolomitic mudstones and shales and by frequently developed paleosol layers, indicating that the boundary of Wumishan cyclothems is marked by an instantaneously-exposed punctuated surface. Viewed form the regularly vertical stacking patterns of Wumishan cyclothems in long-term sequences, 26 third-order sequences may be discerned in Wumishan Formation. These third-order sequences may also be incorporated into six second-order sequences. In order to study the variation range of third-order sea-level changes and the formation period of third-order sequence, 626 cyclothems are discerned in the middle and upper parts of Wumishan Formation where the outcrops are well developed. In terms of the total thickness and the formation period of Mesoproterozoic Wumishan Formation, the crust subsidence rate in the sedimentary period of Wumishan Formation is supposed to be 3 meters at each interval of 100 thousands years. Based on this assumption, Fischer plot might be designed to simulate the third-order sea-level changing pattern.

  18. Water determination in iron oxyhydroxides and iron ores by Karl Fischer titration

    Science.gov (United States)

    da Cunha, Camila C. R. F.; da Costa, Geraldo M.

    2016-08-01

    Protohematite (Fe2-x/3(OH) x O3-x 1 ≤ x hydroxyl groups in their structures. These species were described in prior studies mainly with the aid of X-ray diffraction and Infrared spectroscopy. The existence of these phases in soils might have influence in redox processes, and they were considered as a possible water reservoir in Martian soils. In this study, we have used for the first time the Karl Fischer titration method to determine the amount of water released after heating several synthetic samples of goethite, hematite and natural iron ores at 105, 400, 600 and 900 °C. It was found that heating at 105 °C did not remove all moisture from the samples, and higher temperatures were necessary to completely remove all the absorbed water. The water contents determined at 400, 600 and 900 °C were found to be the same within the experimental errors, suggesting the inexistence of both protohematite and hydrohematite in the investigated samples. Therefore, the above-mentioned effects of these phases in soils might have to be reevaluated.

  19. Effects of Caloric Restriction and Exercise Training on Skeletal Muscle Histochemistry in Aging Fischer 344 Rats

    Directory of Open Access Journals (Sweden)

    David T. Lowenthal

    2006-01-01

    Full Text Available The purpose of this study was to determine the effects of calorie restriction and exercise on hindlimb histochemistry and fiber type in Fischer 344 rats as they advanced from adulthood through senescence. At 10 months of age, animals were divided into sedentary fed ad libitum, exercise (18 m/min, 8% grade, 20 min/day, 5 days/week fed ad libitum, and calorie restricted by alternate days of feeding. Succinic dehydrogenase, myosin adenosine triphosphatase (mATPase at pH 9.4, nicotine adenonine dinucleotide reductase, and Periodic Acid Shiff histochemical stains were performed on plantaris and soleus muscles. The results indicated that aging resulted in a progressive decline in plantaris Type I muscle fiber in sedentary animals, while exercise resulted in maintenance of these fibers. The percent of plantaris Type II fibers increased between 10 and 24 months of age. Exercise also resulted in a small, but significant, increase in the percentage of plantaris Type IIa fibers at 24 months of age. The soleus fiber distribution for Type I fibers was unaffected by increasing age in all groups of animals. The implications of these results suggest the implementation of exercise as a lifestyle modification as early as possible.

  20. Influence of the Feed Gas Composition on the Fischer-Tropsch Synthesis in Commercial Operations

    Institute of Scientific and Technical Information of China (English)

    Yijun Lu; Theo Lee

    2007-01-01

    Key technical challenges relating to the Fischer-Tropsch (F-T) synthesis applied in the commercialization of coal/gas-to-liquids (CTL/GTL) technologies have been reviewed. Based on the experiences accumulated from pilot plant, semi-work test and lab researches, the influences of the H2/CO ratio and the CO2 in the feed gas on the F-T process as well as on CTL/GTL complex in terms of product yields, energy efficiency and carbon utilization efficiency have been studied. Being contrary to the current design schemes for F-T process using the coal derived syngas and the iron-based catalyst, it is suggested to feed the F-T synthesis unit with a syngas having a H2/CO ratio of 0.5 and then adjusting to 1.4 via the recycling process. As a result, the carbon efficiency of the whole plant could be reached to as high as 50%. For the issue of CO2 addition to the feed gas, it is proved that only a diluting role is played under the current commercial slurry phase F-T process.

  1. Development of the Fischer-Tropsch Process: From the Reaction Concept to the Process Book

    Directory of Open Access Journals (Sweden)

    Boyer C.

    2016-05-01

    Full Text Available The process development by IFP Energies nouvelles (IFPEN/ENI/Axens of a Fischer-Tropsch process is described. This development is based on upstream process studies to choose the process scheme, reactor technology and operating conditions, and downstream to summarize all development work in a process guide. A large amount of work was devoted to the catalyst performances on one hand and the scale-up of the slurry bubble reactor with dedicated complementary tools on the other hand. Finally, an original approach was implemented to validate both the process and catalyst on an industrial scale by combining a 20 bpd unit in ENI’s Sannazzaro refinery, with cold mock-ups equivalent to 20 and 1 000 bpd at IFPEN and a special “Large Validation Tool” (LVT which reproduces the combined effect of chemical reaction condition stress and mechanical stress equivalent to a 15 000 bpd industrial unit. Dedicated analytical techniques and a dedicated model were developed to simulate the whole process (reactor and separation train, integrating a high level of complexity and phenomena coupling to scale-up the process in a robust reliable base on an industrial scale.

  2. Development of improved iron Fischer-Tropsch catalysts. Final technical report: Project 6464

    Energy Technology Data Exchange (ETDEWEB)

    Bukur, D.B.; Ledakowicz, S.; Koranne, M. [Texas A and M Univ., College Station, TX (United States). Dept. of Chemical Engineering] [and others

    1994-02-28

    Despite the current worldwide oil glut, the United States will ultimately require large-scale production of liquid (transportation) fuels from coal. Slurry phase Fischer Tropsch (FT) technology, with its versatile product slate, may be expected to play a major role in production of transportation fuels via indirect coal liquefaction. Texas A&M University (TAMU) with sponsorship from the US Department of Energy, Center for Energy and Mineral Resources at TAMU, Texas Higher Education Coordinating Board, and Air Products and Chemicals, Inc., has been working on development of improved iron FT catalysts and characterization of hydrodynamic parameters in two- and three-phase bubble columns with FT derived waxes. Our previous studies have provided an improved understanding of the role of promoters (Cu and K), binders (silica) and pretreatment procedures on catalyst activity, selectivity and longevity (deactivation). The objective of the present contract was to develop improved catalysts with enhanced slurry phase activity and higher selectivity to liquid fuels and wax. This was accomplished through systematic studies of the effects of pretreatment procedures and variations in catalyst composition (promoters and binders). The major accomplishments and results in each of these two main areas of research are summarized here.

  3. Cobalt Fischer-Tropsch catalysts: influence of cobalt dispersion and titanium oxides promotion

    Energy Technology Data Exchange (ETDEWEB)

    Azib, H.

    1996-04-10

    The aim of this work is to study the effect of Sol-Gel preparation parameters which occur in silica supported cobalt catalysts synthesis. These catalysts are particularly used for the waxes production in natural gas processing. The solids have been characterized by several techniques: transmission electron microscopy (TEM), X-ray absorption near edge spectroscopy (XANES), programmed temperature reduction (TPR), infrared spectroscopy (IR), ultraviolet spectroscopy (UV), Magnetism, thermodesorption of H{sub 2} (TPD). The results indicate that the control of the cobalt dispersion and oxide phases nature is possible by modifying Sol-Gel parameters. The catalytic tests in Fischer-Tropsch synthesis were conducted on a pilot unit under pressure (20 atm) and suggested that turnover rates were independent of Co crystallite size, Co phases in the solids (Co deg., cobalt silicate) and titanium oxide promotion. On the other methane, the C{sub 3}{sup +} hydrocarbon selectivity is increased with increasing crystallite size. Inversely, the methane production is favoured by very small crystallites, cobalt silicate increase and titanium addition. However, the latter, used as a cobalt promoter, has a benefic effect on the active phase stability during the synthesis. (author). 149 refs., 102 figs., 71 tabs.

  4. Architectural design and simulation of a virtual memory

    Science.gov (United States)

    Kwok, G.; Chu, Y.

    1971-01-01

    Virtual memory is an imaginary main memory with a very large capacity which the programmer has at his disposal. It greatly contributes to the solution of the dynamic storage allocation problem. The architectural design of a virtual memory is presented which implements by hardware the idea of queuing and scheduling the page requests to a paging drum in such a way that the access of the paging drum is increased many times. With the design, an increase of up to 16 times in page transfer rate is achievable when the virtual memory is heavily loaded. This in turn makes feasible a great increase in the system throughput.

  5. Holographic Memories

    DEFF Research Database (Denmark)

    Ramanujam, P.S.; Holme, NCR; Berg, RH

    1999-01-01

    A Two-dimensional holographic memory for archival storage is described. Assuming a coherent transfer function, an A4 page can be stored at high resolution in an area of 1 mm(2). Recently developed side-chain liquid crystalline azobenzene polyesters are found to be suitable media for holographic...... storage. They exhibit high resolution, high diffraction efficiency, have long storage life, are fully erasable and are mechanically stable....

  6. Transactional Memory

    OpenAIRE

    Grahn, Håkan

    2010-01-01

    Current and future processor generations are based on multicore architectures where the performance increase comes from an increasing number of cores on a chip. In order to utilize the performance potential of multicore architectures the programs also need to be parallel, but writing parallel programs is a non-trivial task. Transactional memory tries to ease parallel program development by providing atomic and isolated execution of code sequences, enabling software composability and protected...

  7. OF THE GREAT TEMPLE OF BEL

    Directory of Open Access Journals (Sweden)

    A. Denker

    2017-02-01

    Full Text Available The Great Temple of Bel in Palmyra was a unique edifice which had blended the well established lines of Greco-Roman architecture with the art and taste of the Orient. With the gilded bronze capitals of its 41 Corinthian columns it was the product of enormous effort and budget. It was the gem of a remarkable epoch of wealthy Palmyra and mighty Roma. With its splendidly decorated adyta ceilings it became a source of inspiration and imagination for Western architecture and decorative arts. While continuing to captivate the World, it was leveled and vanished as a grim result of conflict based vandalism. The aim of this work is to piece together this, the most eloquent and stupendous monument of the Roman East, from its ruins and reconstruct it as it was once extant. Its loss is irreplacable, but its photo-realistic reconstruction can offer some solace by waking the memories of the great temple as in the past. The lost reality of the Great Temple of Bel is revived here by digitally constructing its “ghost images".

  8. Modifed Great Basin Extent (Buffered)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Two different great basin perimeter files were intersected and dissolved using ArcGIS 10.2.2 to create the outer perimeter of the great basin for use modeling...

  9. Great Lakes Environmental Database (GLENDA)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Great Lakes Environmental Database (GLENDA) houses environmental data on a wide variety of constituents in water, biota, sediment, and air in the Great Lakes area.

  10. Tales of War: Childhood Memories of Elderly People

    Directory of Open Access Journals (Sweden)

    Tatyana P. Hlynina

    2014-03-01

    Full Text Available This article is devoted to childhood memories of the war as recorded in the 2000s. It considers peculiarities of children’s memory, and mechanisms for actualization of memories of various events of wartime. It is noted that the memory of the war still remains one of the few sources for the national pride of the modern Russian society. At the same time, rehabilitation of multiple private memories results in erosion of the official version and calls persistently for their reconciliation. Meanwhile memory is no longer viewed by the researcher as a “passive storage of recorded information” but is connected with figural reconstruction of images from the past. Despite a number of peculiarities in children’s memories, they are going to become the touchstone to clear up the peculiarities of forming the memory of the Great Patriotic War, its dynamics and present-day condition.

  11. [Neural correlates of memory].

    Science.gov (United States)

    Fujii, Toshikatsu

    2013-01-01

    Memory can be divided into several types, although all of them involve three successive processes: encoding, storage, and retrieval. In terms of the duration of retention, neurologists classify memory into immediate, recent, and remote memories, whereas psychologists classify memory into short-term and long-term memories. In terms of the content, episodic, semantic, and procedural memories are considered to be different types of memory. Furthermore, researchers on memory have proposed relatively new concepts of memory, i.e., working memory and prospective memory. This article first provides explanations for these several types of memory. Next, neuropsychological characteristics of amnesic syndrome are briefly outlined. Finally, how several different types of memory are affected (or preserved) in patients with amnesic syndrome is described.

  12. Differential Fos expression in the paraventricular nucleus of the hypothalamus, sacral parasympathetic nucleus and colonic motor response to water avoidance stress in Fischer and Lewis rats.

    Science.gov (United States)

    Million, M; Wang, L; Martinez, V; Taché, Y

    2000-09-22

    The responsiveness of hypothalamic CRF to various stressors is reduced in the young female Lewis relative to the histocompatible Fischer rat. Whether such a difference impacts the brain-gut response to water avoidance stress was investigated by monitoring Fos immunoreactivity in the brain and sacral spinal cord and fecal pellet output. Exposure for 60 min to water avoidance stress increased the number of Fos positive cells in the paraventricular nucleus of the hypothalamus (PVN), nucleus tractus solitarius (NTS), and the parasympathetic nucleus of the lumbo-sacral spinal cord (L6-S1) in both Lewis and Fischer rats compared with non stress groups. The Fos response was lower by 32.0% in the PVN, and 63% in sacral parasympathetic nucleus in Lewis compared with Fischer rats while similar Fos expression was observed in the NTS. Stress-induced defecation was reduced by 52% in Lewis compared with Fischer rats while colonic motor response to CRF injected intracisternally resulted in a similar pattern and magnitude of defecation in both strains. The CRF receptor antagonist [D-Phe12,Nle(21,38)C(a)MeLeu(37)]-CRF(12-41) injected intracisternally antagonized partly the defecation response in Lewis and Fischer rats. These data indicate that a lower activation of PVN and sacral parasympathetic nuclei in Lewis compared with Fisher rats may contribute to the differential colonic motor response and that the blunted CRF hypothalamic response to stress, unlike responsiveness to central CRF plays a role.

  13. Performance of a slurry bubble column reactor for Fischer-Tropsch synthesis: Determination of optimum condition

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Kwang-Jae; Kang, Suk-Hwan; Kim, Seung-Moon; Bae, Jong-Wook; Jun, Ki-Won [Advanced Chemical Technology Division, Korea Research Institute of Chemical Technology (KRICT), P.O. Box 107, Yuseong, Daejeon 305-600 (Korea)

    2010-04-15

    The CO conversion and selectivity to C{sub 1}+ and C{sub 11}+ wax products over Co/Al{sub 2}O{sub 3} as well as Ru/Co/Al{sub 2}O{sub 3} Fischer-Tropsch (F-T)catalysts were investigated by varying reaction temperature (210-250 C), system pressure (1.0-3.0 MPa), GHSV (1000-6000 L/kg/h), superficial gas velocity (1.7-13.6 cm/s) and slurry concentration (9.09-26.67 wt.%) in a slurry bubble column reactor (0.05 m diameter x 1.5 m height) to determine the optimum operating conditions. Squalane or paraffin wax was used as initial liquid media. The overall CO conversion increased with increasing reaction temperature, system pressure and catalyst concentration. However, the local maximum CO conversion was exhibited at GHSV of 1500-2000 L/kg/h and superficial gas velocity of 3.4-5.0 cm/s. The CO conversion in the case of Ru/Co/Al{sub 2}O{sub 3} was much higher and stable than that in the case of Co/Al{sub 2}O{sub 3}. The selectivity to C{sub 11}+ wax products increased slightly with increasing GHSV; on the other hand, it decreased with increasing reaction temperature, system pressure, and solid concentration in a slurry bubble column reactor. It could be concluded that the optimum operating conditions based on the yield of hydrocarbons and wax products were; U{sub G} 6.8-10 cm/s, Cs = 15 wt.%, T = 220-230 C, P = 2.0 MPa in a slurry bubble column reactor for F-T synthesis. (author)

  14. Maternal environment alters social interactive traits but not open-field behavior in Fischer 344 rats.

    Science.gov (United States)

    Yamamuro, Yutaka

    2008-10-01

    Although it is recognized that the genetic background governs behavioral phenotypes, environmental factors also play a critical role in the development of various behavioral processes. The maternal environment has a major impact on pups, and the cross-fostering procedure is used to determine the influence of early life experiences. The present study examined the influence of maternal environment on behavioral traits in inbred Fischer 344 (F344) rats. F344/DuCrlCrlj and Wistar (Crlj:WI) pups were fostered from postnatal day 1 as follows: Wistar pups raised by Wistar dams, F344 raised by Wistar, Wistar raised by F344, and F344 raised by F344. At 10 weeks of age, rats were randomly assigned to an open-field test and social interaction test. In the open-field test, irrespective of the rearing conditions, the activity during the first 1 min was significantly lower in F344 rats than in Wistar rats. Latency to the onset of movement showed no difference between groups. In the social interaction test, the recognition performance during the first 1 min in F344 raised by F344 was significantly shorter than that in the other groups. The onset of recognition to a novel social partner in F344 raised by F344 was significantly delayed, and the delay disappeared upon cross-fostering by Wistar dams. These results raise the possibility that the behavioral phenotype of F344 rats results from the interplay of genetic factors and maternal environment during early life, and that F344 rats are a strain with high susceptibility to rearing conditions for the formation of their emotionality.

  15. Age-associated changes in hearts of male Fischer 344/Brown Norway F1 rats.

    Science.gov (United States)

    Walker, Ernest M; Nillas, Michael S; Mangiarua, Elsa I; Cansino, Sylvestre; Morrison, Ryan G; Perdue, Romaine R; Triest, William E; Wright, Gary L; Studeny, Mark; Wehner, Paulette; Rice, Kevin M; Blough, Eric R

    2006-01-01

    Aging is associated with left ventricular hypertrophy, dilatation, and fibrosis of the heart. The Fischer 344/Brown Norway F1 (F344/BNF1) rat is recommended for age-related studies by the National Institutes on Aging because this hybrid rat lives longer and has a lower rate of pathological conditions than inbred rats. However, little is known about age-associated changes in cardiac and aortic function and structure in this model. This study evaluated age-related cardiac changes in male F344/BNF1 rats using ECHO, gross, and microscopic examinations. Rats aged 6-, 30-, and 36-mo were anesthetized and two-dimensional ECHO measurements, two-dimensional guided M-mode, Doppler M-mode, and other recordings from parasternal long- and short-axis views were obtained using a Phillips 5500 ECHO system with a 12 megahertz transducer. Hearts and aortas from sacrificed rats were evaluated grossly and microscopically. The ECHO studies revealed persistent cardiac arrhythmias (chiefly PVCs) in 72% (13/18) of 36-mo rats, 10% (1/10) of 30-mo rats, and none in 6-mo rats (0/16). Gross and microscopic studies showed left ventricular (LV) dilatation, borderline to mild hypertrophy, and areas of fibrosis that were common in 36-mo rats, less evident in 30-mo rats, and absent in 6-mo rats. Aging was associated with mild to moderate decreases of LV diastolic and systolic function. Thus, male F344/BN F1 rats demonstrated progressive age-related (a) decline in cardiac function (diastolic and systolic indices), (b) LV structural changes (chamber dimensions, volumes, and wall thicknesses), and (c) persistent arrhythmias. These changes are consistent with those in humans. The noninvasive ECHO technique offers a means to monitor serial age-related cardiac failure and therapeutic responses in the same rats over designated time intervals.

  16. Carcinogenicity of bisphenol-A in Fischer rats and B6C3F1 mice.

    Science.gov (United States)

    Huff, J

    2001-11-01

    Bisphenol-A (BP-A; 4,4'-isopropylidenediphenol) is a monomer of plastics commonly used in various consumer products, and is used as an intermediate in the manufacture of epoxy, polycarbonate, and polyester-styrene resins. A National Toxicology Program carcinogenesis bioassay of BP-A (>98% pure) was conducted by feeding diets containing 0, 1000, or 2000 ppm BP-A to groups of 50 male and 50 female Fischer (F)344 rats; 0, 1000, or 5000 ppm to groups of 50 male B6C3F1 mice; and 0, 5000, or 10,000 ppm to groups of 50 female B6C3F1 mice for 103 weeks. The mean body weights of the low- and high-dose rats and of female mice and high-dose male mice were lower than those of the controls throughout much of the study. Lower body weight gains in rats were likely caused by reduced food consumption. Survivals were comparable among groups. Regarding neoplasia, leukemias occurred at increased incidences in BP-A-dosed rats of both sexes: male, 13/50 controls vs 12/50 low-dose and 23/50 high-dose (P Toxicology Program concluded that there was no convincing evidence that BP-A was carcinogenic for rats or mice. However, the marginal increases in leukemias in male and female rats, along with increases in the combined incidence of lymphomas and leukemias in male mice, suggest that BP-A may be associated with increased cancers of the hematopoietic system. Increases in interstitial-cell tumors of the testes in rats were also evidence of carcinogenesis, as was the unusual occurrence of mammary gland fibroadenomas in male rats.

  17. Thermodynamic optimization of biomass gasification for decentralized power generation and Fischer-Tropsch synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Buragohain, Buljit; Mahanta, Pinakeswar; Moholkar, Vijayanand S. [Center for Energy, Indian Institute of Technology, Guwahati, 781 039, Assam (India)

    2010-06-15

    In recent years, biomass gasification has emerged as a viable option for decentralized power generation, especially in developing countries. Another potential use of producer gas from biomass gasification is in terms of feedstock for Fischer-Tropsch (FT) synthesis - a process for manufacture of synthetic gasoline and diesel. This paper reports optimization of biomass gasification process for these two applications. Using the non-stoichometric equilibrium model (SOLGASMIX), we have assessed the outcome of gasification process for different combinations of operating conditions. Four key parameters have been used for optimization, viz. biomass type (saw dust, rice husk, bamboo dust), air or equivalence ratio (AR = 0, 0.2, 0.4, 0.6, 0.8 and 1), temperature of gasification (T = 400, 500, 600, 700, 800, 900 and 1000 C), and gasification medium (air, air-steam 10% mole/mole mixture, air-steam 30%mole/mole mixture). Performance of the gasification process has been assessed with four measures, viz. molar content of H{sub 2} and CO in the producer gas, H{sub 2}/CO molar ratio, LHV of producer gas and overall efficiency of gasifier. The optimum sets of operating conditions for gasifier for FT synthesis are: AR = 0.2-0.4, Temp = 800-1000 C, and gasification medium as air. The optimum sets of operating conditions for decentralized power generation are: AR = 0.3-0.4, Temp = 700-800 C with gasification medium being air. The thermodynamic model and methodology presented in this work also presents a general framework, which could be extended for optimization of biomass gasification for any other application. (author)

  18. Malnutrition alters the cardiovascular responses induced by central injection of tityustoxin in Fischer rats.

    Science.gov (United States)

    Silva, Fernanda Cacilda Santos; Guidine, Patrícia Alves; Ribeiro, Mara Fernandes; Fernandes, Luciano Gonçalves; Xavier, Carlos Henrique; de Menezes, Rodrigo Cunha; Silva, Marcelo Eustáquio; Moraes-Santos, Tasso; Moraes, Márcio Flávio; Chianca, Deoclécio Alves

    2013-12-15

    Scorpion envenoming and malnutrition are considered two important public health problems in Brazil, involving mainly children. Both these conditions are more common among the economically stratified lower income portion of the population, thus suggesting that these factors should be analyzed concomitantly. It is known that cardiorespiratory manifestations, as cardiac arrhythmias, arterial hypertension and hypotension, pulmonary edema and circulatory failure are the main "causa mortis" of scorpion envenomation. Additionally, there are evidences in the literature that deficiencies in dietary intake endanger the CNS and modify the cardiovascular homeostasis. Then, the objective of this work is to evaluate the protein malnourished effect on cardiovascular responses induced by tityustoxin (TsTX, an α-type toxin extracted from the Tityus serrulatus scorpion venom). Fischer rats (n = 20) were injected i.c.v. with TsTX and divided in control and malnorished groups, which were, respectively, submitted to a control and a low-protein diet. Arterial pressure recordings were done until death of the animals. Although both groups presented an increased mean arterial pressure after TsTX injection, this increase was smaller and delayed in malnourished rats, when compared to control rats. In addition, heart rate increased only in rats from the control group. Finally, malnourished rats had an increase in survival time (9:9/13.5 vs. 15.5:10.5/18 min; p = 0.0009). In summary, our results suggest that the protein restriction attenuates the cardiovascular manifestations resulting from TsTX action on CNS.

  19. Fischer-Tropsch synthesis in a two-phase reactor with presaturation

    Energy Technology Data Exchange (ETDEWEB)

    Wache, W. [Bayernoil Raffineriegesellschaft mbH, Ingolstadt (Germany); Datsevich, L.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering

    2006-07-01

    In industry, the Fischer-Tropsch (FTS) synthesis is mostly carried out in multiphase slurry or multitubular reactors (MTR), where gaseous reactants and liquid products (hydrocarbons up to waxes) are contacted in the presence of a solid catalyst. Such reactors are characterized by a complex temperature control, necessity of gas recycling, complicated design and problematic scale-up. A new alternative to conventional FTS-processes is the presaturated-one-liquid-phase (POLF) technology. The basic principle of this concept is a recirculation of the liquid phase, in which a gaseous reactant(s) is (are) solved before entering the fixed-bed reactor. In a simple column reactor, this technology ensures the effective heat removal and intensive fluid-solid mass transfer. In comparison to conventional reactors, the plant design is very simple, the temperature control is uncomplicated and there is no danger of any runaways. That results in lower investment and operation costs as well as in higher reliability. The experiments show that the conversion of CO and the product distribution of hydrocarbons are practically independent on the mode of operation (two- or three-phase system). However, in the lab-scale apparatus, water is accumulated in the loop, which leads to a loss of the catalyst activity (due to Fe-carbonate). In a technical process, the water accumulation in a loop can be eluded by taking an oil free of water from the oil work-up unit. Our experiments with the removal of water from the stream by a zeolite demonstrate a much promising applicability of the POLF process to the industrial FTS. (orig.)

  20. Correlation between Fischer-Tropsch catalytic activity and composition of catalysts

    Directory of Open Access Journals (Sweden)

    Subbarao Duvvuri

    2011-11-01

    Full Text Available Abstract This paper presents the synthesis and characterization of monometallic and bimetallic cobalt and iron nanoparticles supported on alumina. The catalysts were prepared by a wet impregnation method. Samples were characterized using temperature-programmed reduction (TPR, temperature-programmed oxidation (TPO, CO-chemisorption, transmission electron microscopy (TEM, field emission scanning electron microscopy (FESEM-EDX and N2-adsorption analysis. Fischer-Tropsch synthesis (FTS was carried out in a fixed-bed microreactor at 543 K and 1 atm, with H2/CO = 2 v/v and space velocity, SV = 12L/g.h. The physicochemical properties and the FTS activity of the bimetallic catalysts were analyzed and compared with those of monometallic cobalt and iron catalysts at similar operating conditions. H2-TPR analysis of cobalt catalyst indicated three temperature regions at 506°C (low, 650°C (medium and 731°C (high. The incorporation of iron up to 30% into cobalt catalysts increased the reduction, CO chemisorption and number of cobalt active sites of the catalyst while an opposite trend was observed for the iron-riched bimetallic catalysts. The CO conversion was 6.3% and 4.6%, over the monometallic cobalt and iron catalysts, respectively. Bimetallic catalysts enhanced the CO conversion. Amongst the catalysts studied, bimetallic catalyst with the composition of 70Co30Fe showed the highest CO conversion (8.1% while exhibiting the same product selectivity as that of monometallic Co catalyst. Monometallic iron catalyst showed the lowest selectivity for C5+ hydrocarbons (1.6%.

  1. Conditions for accurate Karl Fischer coulometry using diaphragm-free cells.

    Science.gov (United States)

    Nordmark, U; Cedergren, A

    2000-01-01

    Factors influencing the extent of formation of oxidizable reduction products in coulometric cells used for Karl Fischer (KF) determination of water were investigated. For methanolic KF reagents buffered with imidazole (Im) or diethanolamine (DEA) (separately or in combination), three parameters were found to be of outmost importance: the cathodic current density, the pH, and the concentration of protonated base (ImH+ or DEAH+). For reagents buffered with only Im, the relative formation of oxidizable reduction products varied in the range 2-40%; i.e., 51-70 micrograms of water was found for a 50 micrograms water sample, depending on the above-mentioned parameters. The lowest values were observed for reagents having a pH around 10 in combination with cathodic current densities in the range 2000-5000 mA cm-2. For all the Imbuffered reagents investigated, the addition of modifiers such as chloroform, hexanol, and carbon tetrachloride was found to decrease the formation of oxidizable reduction products significantly. For example, a reagent buffered at pH 10 containing 1 M hexanol gave less than 0.3% formation in the current density interval from 200 to 4000 mA cm-2. The best reagents based on the above-mentioned modifiers were tested in the continuous coulometric mode with errors typically in the interval 0-0.5% using optimum conditions. One prerequisite for obtaining such small errors with diaphragm-free continuous coulometry is to use a cathode area no larger than 0.002 cm2. For some of the reagents based on both Im and DEA, the formation of oxidizable reduction products was close to zero at certain current densities, although the analytical performance was not as good as for the reagents buffered solely by Im due to longer conditioning and titration times.

  2. An analysis of Fischer-Tropsch synthesis by the bond-order-conservation-Morse-potential approach

    Science.gov (United States)

    Shustorovich, Evgeny; Bell, Alexis T.

    1991-06-01

    The BOC-MP (bond-order-conservation-Morse-potential) approach has been used to calculate the heats of chemisorption of adspecies and activation barriers for elementary reaction steps envisioned to occur during Fischer-Tropsch (F-T) synthesis over the periodic series Fe/W(110), Ni(111), Pt(111), and Cu(111). Dissociative adsorption of CO to form carbidic carbon is projected to occur spontaneously on Fe/W(110) and with a small activation barrier on Ni(111). The calculated barrier heights for this reaction on Pt(111) and Cu(111) are high enough to preclude appreciable dissociation of CO. Hydrogen-assisted dissociation of CO s is found to have an even smaller activation barrier on Fe/W and Ni, but not on Pt or Cu. On all the metal surfaces, the energetically preferred path for initiation of alkyl chain growth is via insertion of a CH 2 group into the carbon-metal bond of a CH 3 group. The activation barrier for CO insertion into the metal-carbon bond of a CH 3 group is greater than that for CH 2 insertion. As a consequence, the acetyl group formed by CO insertion serves mainly as a precursor to oxygenated products. On Fe/W, Ni, and Pt the activation barrier for termination of alkyl chain growth by β-elimination of hydrogen is found to be lower than that for α-addition of hydrogen, and as a consequence olefins are projected to be formed more readily than paraffins. By using as examples Fe(100) and Fe(100)-c(2 × 2)C,O, it is shown that carburization of an Pe surface reduces the heats of adsorption of C, O, and CO, resulting in nondissociative chemisorption of CO, similar to that on Pt(111). The BOC-MP model projections are consistent with the available experimental data and contain claims that can be tested experimentally in the future.

  3. How to make Fischer-Tropsch catalyst scale-up fully reliable?

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, L.; Heraud, J.P.; Forret, A.; Gazarian, J. [IFP Energies nouvelles, Solaize (France); Cornaro, U. [Eni S.p.A., San Donato Milanese (Italy). R and M Div.; Carugati, A. [Eni S.p.A., San Donato Milanese (Italy). E and P Div.

    2011-07-01

    Several players use Fischer-Tropsch catalysts and technologies industrially [1,2] or declare to be ready for industrial application [e.g. 3]. Present R and D aims to further increase capacities per train [4] or improve catalyst selectivity towards middle distillates [5]. For transforming promising laboratory results into industrial reality, representative catalyst testing is of particular importance for slurry bubble column FT. In the Italian eni's refinery of Sannazzaro, a 20 BPD slurry bubble column pilot plant has cumulated more than 20,000 hours time on stream in different campaigns. Non reactive slurry bubble columns corresponding to reactor capacities between 20 BPD and 1000 BPD permitted to determine the profiles for gas hold up and liquid velocities as a function of gas flow, catalyst loading, reactor diameter and internals. A hydrodynamic model based on those data led to design a Large Validation Tool, which can reproduce under reaction conditions a high mechanical stress on the catalyst equivalent to the one experienced in an industrial 15000 BPD reactor. While those tools have proven to be efficient for developing an industrial scale FT catalyst [3], they predict today in a representative manner fines formation, activity and selectivity of improved catalysts and / or for optimization of operation conditions to increase the capacity per train. We compare the here presented approach to others. We have found that it is mandatory to combine chemical stress from the reaction products with mechanical stress as experienced in an industrial slurry bubble column, in order to evaluate in a reliable way catalyst performance stability and fines formation. The potential of improvements are discussed. (orig.)

  4. Heightened inflammasome activation is linked to age-related cognitive impairment in Fischer 344 rats

    Directory of Open Access Journals (Sweden)

    Mawhinney Lana J

    2011-12-01

    Full Text Available Abstract Background Members of the mammalian nucleotide binding domain, leucine-rich repeat (LRR-containing receptor (NLR family of proteins are key modulators of innate immunity regulating inflammation. Our previous work has shown that among the members of this family, NLRP1/NALP1, present in neurons, plays a crucial role in inflammasome formation and the production of the inflammatory cytokines interleukin (IL -1β and IL-18 after various types of central nervous system injury. Results We investigated whether age-related cognitive decline may involve a heightened inflammatory response associated with activation of the NLRP1 inflammasome in the hippocampus. Young (3 months and aged (18 months male Fischer 344 rats were tested in a spatial acquisition task via Morris water maze. Following behavioral testing, hippocampal lysates were assayed for expression of NLRP1 inflammasome components and inflammatory cytokines. Hippocampal lysates from aged rats showed significantly higher levels of NLRP1 inflammasome constituents, caspase-1, caspase-11, the purinergic receptor P2X7, pannexin-1 and X-linked inhibitor of apoptosis (XIAP than lysates from younger animals. Following treatment with probenecid, an inhibitor or pannexin-1, aged animals demonstrated reduction in inflammasome activation and improvement in spatial learning performance. Conclusions Our behavioral findings are consistent with increases in IL-1β and IL-18 that have been previously shown to correlate with spatial learning deficits. Probenecid reduced activated caspase-1 and ameliorated spatial learning deficits in aged rats. Thus, aging processes stimulate activation of the NLRP1 inflammasome and secretion of IL-1β and IL-18 that may contribute to age-related cognitive decline in the growing elderly population. Moreover, probenecid may be potentially useful as a therapy to improve cognitive outcomes in the aging population.

  5. Age-related Changes in the Fracture Resistance of Male Fischer F344 Rat Bone

    Science.gov (United States)

    Uppuganti, Sasidhar; Granke, Mathilde; Makowski, Alexander J.; Does, Mark D.; Nyman, Jeffry S.

    2015-01-01

    In addition to the loss in bone volume that occurs with age, there is a decline in material properties. To test new therapies or diagnostic tools that target such properties as material strength and toughness, a pre-clinical model of aging would be useful in which changes in bone are similar to those that occur with aging in humans. Toward that end, we hypothesized that similar to human bone, the estimated toughness and material strength of cortical bone at the apparent-level decreases with age in the male Fischer F344 rat. In addition, we tested whether the known decline in trabecular architecture in rats translated to an age-related decrease in vertebra (VB) strength and whether non-X-ray techniques could quantify tissue changes at micron and sub-micron length scales. Bones were harvested from 6-, 12-, and 24-month (mo.) old rats (n=12 per age). Despite a loss in trabecular bone with age, VB compressive strength was similar among the age groups. Similarly, whole-bone strength (peak force) in bending was maintained (femur) or increased (radius) with aging. There was though an age-related decrease in post-yield toughness (radius) and bending strength (femur). The ability to resist crack initiation was actually higher for the 12-mo. and 24-mo. than for 6-mo. rats (notch femur), but the estimated work to propagate the crack was less for the aged bone. For the femur diaphysis region, porosity increased while bound water decreased with age. For the radius diaphysis, there was an age-related increase in non-enzymatic and mature enzymatic collagen crosslinks. Both Raman spectroscopy and reference point indentation detected differences in tissue properties with age, though the trends did not necessarily match observations from human tissue. PMID:26610688

  6. A DFT and structural investigation of the conformations of Fischer carbene complexes

    Science.gov (United States)

    Landman, Marilé

    2015-09-01

    A set of different Fischer carbene complexes of group VI and VII metals, with varied heteroatom and heteroaromatic substituents on the carbene carbon atom, was studied. Density functional theory as well as single crystal diffraction techniques were employed to investigated the most stable conformation of these complexes. The complexes studied, [M(CO)4L{C(X)Z}], with L = PPh3 or CO, X = ethoxy (-OCH2CH3) or amino (-NH2 or NHCy) substituents as the heteroatom carbene substituents, Z = 2-furyl (-C4H3O), 2-thienyl (-C4H3S), 2-(N-methyl)pyrrolyl (-C4H3NCH3) as the second carbene substituent had their substituents varied systematically to give all the possible conformations of these complexes. The conformations of the complexes, in particular the relative orientations of the heteroatoms in the molecule (syn vs. anti), E/Z isomerism in the aminocarbene complexes and cis/trans isomerism in the ligand substituted complexes as well as various combinations of these aspects, were studied. In general, it was found that the most stable conformation theoretically as well as in the solid state for most of the complexes preferred the syn conformation. The Z-isomer is generally preferred over the E isomer while the cis is more predominant than the trans isomer. Using DFT and NBO calculations, explanations for the preferred conformations were explored. It was concluded that both steric and electronic factors influence the conformations of the carbene complexes, with the extent of contribution of these two factors varying for each of the different carbene substituents.

  7. Multiplicative contexts in associative memories.

    Science.gov (United States)

    Mizraji, E; Pomi, A; Alvarez, F

    1994-01-01

    A system of networks, consisting of a first net that constructs the Kronecker product between two vectors and then sends it to a second net that sustains a correlation memory, defines a context-dependent associative memory. In the real nervous system of higher mammals, the anatomy of the neural connections surely exhibits a considerable amount of local imprecision superimposed on a regular global layout. In order to evaluate the potentialities of the multiplicative devices to constitute plausible biological models, we analyse the performances of a context-dependent memory when the multiplicative net, responsible of the construction of the Kronecker product, presents an incomplete connectivity. Our study shows that a large dimensional system is able to support a considerable amount of incompleteness in the connectivity without a great deterioration of the memory. We establish a scaling relationship between the degree of incompleteness, the capacity of the memory, and the tolerance threshold to imperfections in the output. We then analyse some performances that show the versatility of this kind of network to represent a variety of functions. These functions include a context-modulated novelty filter, a network that computes logical modalities and an adaptive searching device.

  8. Efficacy of argon-helium cryosurgery for gliomas in 9L/Fischer344 rats%氩氦冷冻治疗9L/Fischer344大鼠脑胶质瘤疗效观察

    Institute of Scientific and Technical Information of China (English)

    刘剑; 马国亮; 夏爱祥; 张世忠; 黄传平; 林武鹏; 王德才

    2013-01-01

    Objective To research the efficacy of argon-helium cryotherapy for glioma and the prognosis in 9L/Fischer344 rats.Methods Fischer344 rat glioma models were successfully established and divided into blank control group,surgery group and cryotherapy group,10 rats each.The size of the tumor was measured and calculated by vemier caliper.The behavior and survival of rats was observed before and atter cryotherapy.Results The survival time in blank control group,surgery group and cryotherapy group was 78.5±1.1,171.0±10.8 and 252.8±5.0 days respectively,and the difference was statistically significant (P =0.002).The tumor volume showed a trend to decrease in cryotherapy group.Conclusions Cryosurgery is an effective treatment for glioma,presumably due to the tumor cell rupture-caused antigen exposure stimulating the body to produce anti-tumor antibodies.%目的 研究氩氦冷冻治疗9L/Fischer344大鼠脑胶质瘤的疗效及预后.方法 Fischer344大鼠胶质瘤模型建立成功后,随机分为空白对照组、手术组、氩氦冷冻组,每组10只.游标卡尺测量并计算肿瘤体积,观察各组大鼠行为及生存期.结果 空白对照组、手术组和氩氦冷冻组大鼠生存时间分别为(78.5±1.1)d、(171.0±10.8)d和(252.8±5.0)d,差异具有统计学意义(P=0.002).氩氦冷冻组肿瘤体积呈逐渐缩小趋势.结论 氩氦冷冻是治疗胶质瘤有效方法,推测可能与瘤细胞破裂,抗原暴露,而刺激机体产生抗肿瘤的抗体有关.

  9. Fischer-Tropsch Synthesis: Development of a Micro kinetic Model for Metal Catalysis; La synthese Fischer-Tropsch: developpement d'un modele microcinetique pour la catalyse sur metaux

    Energy Technology Data Exchange (ETDEWEB)

    Lozano-Blanco, G.; Thybaut, J.W.; Marin, G.B. [Ghent Univ., Lab. voor Petrochemische Techniek (Belgium); Surla, K.; Galtier, P. [Institut Francais du Petrole, 69 - Vernaison (France)

    2006-07-01

    The construction of a single-event micro-kinetic (SEMK) model for metal catalysis using Fischer-Tropsch synthesis as example reaction is addressed. SEMK's describe the full product distribution with a limited number of kinetic parameters. A computer algorithm is required to generate all the elementary steps and species of the reaction network. Reacting and intermediate species are represented with Boolean matrices and standardized labels. The adjustable model parameters are the atomic chemisorption enthalpies of carbon, oxygen and hydrogen on the metal surface and the single-event kinetic coefficients of the kinetically relevant reaction families. (authors)

  10. Transactional Memory

    CERN Document Server

    Harris, Tim; Rajwar, Ravi

    2010-01-01

    The advent of multicore processors has renewed interest in the idea of incorporating transactions into the programming model used to write parallel programs.This approach, known as transactional memory, offers an alternative, and hopefully better, way to coordinate concurrent threads. The ACI(atomicity, consistency, isolation) properties of transactions provide a foundation to ensure that concurrent reads and writes of shared data do not produce inconsistent or incorrect results. At a higher level, a computation wrapped in a transaction executes atomically - either it completes successfullyand

  11. Effect of Lanthanum as a Promoter on Fe-Co/SiO2 Catalyst for Fischer-Tropsch Synthesis

    Directory of Open Access Journals (Sweden)

    Ali Abbasi

    2014-03-01

    Full Text Available Iron-Cobalt catalyst is well known from both operational and economical aspects for Fischer-Tropsch synthesis. Effort to increase the efficiency of this kind of catalyst is an important research topic. In this work, the effect of lanthanum on characteristic behavior, conversion and selectivity of a Fe-Co/SiO2 Fischer-Tropsch catalyst was studied. The Fe-Co-La/SiO2 Catalysts were prepared using an incipient wetness impregnation method. These catalysts were then characterized by XRF-EDAX, BET and TPR techniques, and their performance were evaluated in a lab-scale reactor at 250ºC, H2/CO = 1.8 of molar ratio, 16 barg pressure and GHSV=600 h-1. TPR analysis showed that the addition of La lowered the reduction temperature of Fe-Co catalyst, and due to a lower temperature, the sintering of the catalyst can be mitigated. Furthermore, from the micro reactor tests (about 4 days, it was found that lanthanum promoted catalyst had higher selectivity toward hydrocarbons, and lower selectivity toward CO2.Received: 8th July 2013; Revised: 18th November 2013; Accepted: 1st December 2013[How to Cite: Abbasi, A., Ghasemi, M., Sadighi, S. (2014. Effect of Lanthanum as a Promoter on Fe-Co/SiO2 Catalyst for Fischer-Tropsch Synthesis. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (1: 23-27. (doi:10.9767/bcrec.9.1.5142.23-27][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.1.5142.23-27

  12. An innovative catalyst system for slurry-phase Fischer-Tropsch synthesis: Cobalt plus a water-gas-shift catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Satterfield, C.N.; Yates, I.C.; Chanenchuk, C.

    1991-07-01

    The feasibility of using a mechanical mixture of a Co/MgO/SiO{sub 2} Fischer-Tropsch catalyst and a Cu-ZnO/Al{sub 2}O{sub 3} water-gas-shift (WGS) catalyst for hydrocarbon synthesis in a slurry reactor has been established. Such a mixture can combine the superior product distribution from cobalt with the high activity for the WGS reaction characteristic of iron. Weight ratios of Co/MgO/SiO{sub 2} to Cu-ZnO/Al{sub 2}O{sub 3} of 0.27 and 0.51 for the two catalysts were studied at 240{degrees}C, 0.79 MPa, and in situ H{sub 2}/CO ratios between 0.8 and 3.0. Each catalyst mixture showed stable Fischer-Tropsch activity for about 400 hours-on-stream at a level comparable to the cobalt catalyst operating alone. The Cu-ZnO/Al{sub 2}O{sub 3} catalyst exhibited a very slow loss of activity under these conditions, but when operated alone it was stable in a slurry reactor at 200--220{degrees}C, 0.79--1.48 MPa, and H{sub 2}/CO in situ ratios between 1.0 and 2.0. The presence of the water-gas-shift catalyst did not affect the long-term stability of the primary Fischer-Tropsch selectivity, but did increase the extent of secondary reactions, such as l-alkene hydrogenation and isomerization.

  13. Memory effects in turbulence

    Science.gov (United States)

    Hinze, J. O.

    1979-01-01

    Experimental investigations of the wake flow of a hemisphere and cylinder show that such memory effects can be substantial and have a significant influence on momentum transport. Memory effects are described in terms of suitable memory functions.

  14. Effect of the Polymeric Stabilizer in the Aqueous Phase Fischer-Tropsch Synthesis Catalyzed by Colloidal Cobalt Nanocatalysts

    Directory of Open Access Journals (Sweden)

    Jorge A. Delgado

    2017-03-01

    Full Text Available A series of small and well defined cobalt nanoparticles were synthesized by the chemical reduction of cobalt salts in water using NaBH4 as a reducing agent and using various polymeric stabilizers. The obtained nanocatalysts of similar mean diameters (ca. 2.6 nm were fully characterized and tested in the aqueous phase Fischer-Tropsch Synthesis (AFTS. Interestingly, the nature and structure of the stabilizers used during the synthesis of the CoNPs affected the reduction degree of cobalt and the B-doping of these NPs and consequently, influenced the performance of these nanocatalysts in AFTS.

  15. Effect of the Polymeric Stabilizer in the Aqueous Phase Fischer-Tropsch Synthesis Catalyzed by Colloidal Cobalt Nanocatalysts

    Science.gov (United States)

    Delgado, Jorge A.; Claver, Carmen; Castillón, Sergio; Curulla-Ferré, Daniel; Godard, Cyril

    2017-01-01

    A series of small and well defined cobalt nanoparticles were synthesized by the chemical reduction of cobalt salts in water using NaBH4 as a reducing agent and using various polymeric stabilizers. The obtained nanocatalysts of similar mean diameters (ca. 2.6 nm) were fully characterized and tested in the aqueous phase Fischer-Tropsch Synthesis (AFTS). Interestingly, the nature and structure of the stabilizers used during the synthesis of the CoNPs affected the reduction degree of cobalt and the B-doping of these NPs and consequently, influenced the performance of these nanocatalysts in AFTS. PMID:28336892

  16. Age-related changes in the percentage of oleate in adipose tissue of male and female Fischer rats

    DEFF Research Database (Denmark)

    Thorling, E.B.; Hansen, Harald S.

    1995-01-01

    Fischer 344 rats showed sex difference in the percentage of oleate in lipids of the omental adipose tissue (Thorling, E.B. and Overvad, K. (1994) Nutr. Res. 14, 569-576). The development of this difference was studied with respect to time in rats maintained on laboratory chow, from the age of 3...... in the female than in the male rats, and this difference increased with age. The results of the present study suggest that these changes in percentage of oleate in adipose tissue lipids may partly have been caused by an effect of sex steroids on the delta-9-desaturase....

  17. Study of structural and catalytic properties of Ni catalysts prepared from inorganic complex precursor for Fischer-Tropsch synthesis

    Science.gov (United States)

    Saheli, Sania; Rezvani, Ali Reza; Malekzadeh, Azim

    2017-09-01

    The silica- and alumina- supported Ni catalysts synthesized by thermal decomposition of inorganic precursors were evaluated for Fischer-Tropsch synthesis (FTS); the structural properties and performance of the catalysts were compared to those of samples constructed via impregnation method. The results revealed that the synthesized catalysts have higher catalytic activity comparison to those prepared via the conventional impregnation method. The effect of the preparation method on the structural properties shows that synthesizing the catalyst through inorganic precursor route is more appropriate. Characterization of catalysts is carried out using inductively coupled plasma (ICP), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and BET specific surface area.

  18. A Smoothing Method with Appropriate Parameter Control Based on Fischer-Burmeister Function for Second-Order Cone Complementarity Problems

    Directory of Open Access Journals (Sweden)

    Yasushi Narushima

    2013-01-01

    Full Text Available We deal with complementarity problems over second-order cones. The complementarity problem is an important class of problems in the real world and involves many optimization problems. The complementarity problem can be reformulated as a nonsmooth system of equations. Based on the smoothed Fischer-Burmeister function, we construct a smoothing Newton method for solving such a nonsmooth system. The proposed method controls a smoothing parameter appropriately. We show the global and quadratic convergence of the method. Finally, some numerical results are given.

  19. STRUKTUR DAN PROSES MEMORI

    Directory of Open Access Journals (Sweden)

    Magda Bhinnety

    2015-09-01

    Full Text Available This paper describes structures and processes of human memory system according to the modal model. Sensory memory is described as the first system to store information from outside world. Short‐term memory, or now called working memory, represents a system characterized by limited ability in storing as well as retrieving information. Long‐term memory on the hand stores information larger in amount and longer than short‐term memory

  20. Memory, collective memory, orality and the gospels

    African Journals Online (AJOL)

    Test

    2011-06-07

    Jun 7, 2011 ... with collective memory theory in the works of Halbwachs, Connerton, Gillis, Fentress and. Wickham, Olick, Schwartz ..... critical importance of cultural memory for (re)constructing history. ...... Frankfurt am Main. Baddeley, A.D. ...

  1. Primeiro registro de Plesiophysa guadeloupensis ("Fischer" Mazé no Estado do Rio de Janeiro, Brasil First report of Plesiophysa guadeloupensis ("Fischer" Mazé in the State of Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Monica A. Fernandez

    2006-09-01

    Full Text Available O presente trabalho trata do primeiro registro de Plesiophysa guadeloupensis (" Fischer" Mazé, 1883 no Estado do Rio de Janeiro, no município de Itaocara. Os exemplares foram coletados em uma área alagada situada no distrito de Jaguarembé em abril/maio de 2003 e março de 2005. São mencionadas as espécies encontradas em simpatria com P. guadeloupensis, assim como algumas características físicas e químicas da água (pH, oxigênio dissolvido e temperatura, além da atual distribuição geográfica do gênero Plesiophysa no Brasil.This paper deals with the first report of Plesiophysa guadeloupensis (" Fischer" Mazé, 1883 from Rio de Janeiro State, in the municipality of Itaocara. The gastropods were collected at a swamp situated in the district of Jaguarembé in April-May 2003 and March 2005. Other species found together with P. guadeloupensis are mentioned, as well as some physical and chemical characteristics of the water (pH, dissolved oxygen and temperature, and the geographical distribution of the genus Plesiophysa in Brazil.

  2. Closed system Fischer-Tropsch synthesis over meteoritic iron, iron ore and nickel-iron alloy. [deuterium-carbon monoxide reaction catalysis

    Science.gov (United States)

    Nooner, D. W.; Gibert, J. M.; Gelpi, E.; Oro, J.

    1976-01-01

    Experiments were performed in which meteoritic iron, iron ore and nickel-iron alloy were used to catalyze (in Fischer-Tropsch synthesis) the reaction of deuterium and carbon monoxide in a closed vessel. Normal alkanes and alkenes and their monomethyl substituted isomers and aromatic hydrocarbons were synthesized. Iron oxide and oxidized-reduced Canyon Diablo used as Fischer-Tropsch catalysts were found to produce aromatic hydrocarbons in distributions having many of the features of those observed in carbonaceous chondrites, but only at temperatures and reaction times well above 300 C and 6-8 h.

  3. What's Working in Working Memory Training? An Educational Perspective

    Science.gov (United States)

    Redick, Thomas S.; Shipstead, Zach; Wiemers, Elizabeth A.; Melby-Lervåg, Monica; Hulme, Charles

    2015-01-01

    Working memory training programs have generated great interest, with claims that the training interventions can have profound beneficial effects on children's academic and intellectual attainment. We describe the criteria by which to evaluate evidence for or against the benefit of working memory training. Despite the promising results of initial…

  4. Estimating and Forecasting Generalized Fractional Long Memory Stochastic Volatility Models

    NARCIS (Netherlands)

    S. Peiris (Shelton); M. Asai (Manabu); M.J. McAleer (Michael)

    2016-01-01

    textabstractIn recent years fractionally differenced processes have received a great deal of attention due to its flexibility in financial applications with long memory. This paper considers a class of models generated by Gegenbauer polynomials, incorporating the long memory in stochastic volatility

  5. What's Working in Working Memory Training? An Educational Perspective

    Science.gov (United States)

    Redick, Thomas S.; Shipstead, Zach; Wiemers, Elizabeth A.; Melby-Lervåg, Monica; Hulme, Charles

    2015-01-01

    Working memory training programs have generated great interest, with claims that the training interventions can have profound beneficial effects on children's academic and intellectual attainment. We describe the criteria by which to evaluate evidence for or against the benefit of working memory training. Despite the promising results of initial…

  6. Speaker's voice as a memory cue.

    Science.gov (United States)

    Campeanu, Sandra; Craik, Fergus I M; Alain, Claude

    2015-02-01

    Speaker's voice occupies a central role as the cornerstone of auditory social interaction. Here, we review the evidence suggesting that speaker's voice constitutes an integral context cue in auditory memory. Investigation into the nature of voice representation as a memory cue is essential to understanding auditory memory and the neural correlates which underlie it. Evidence from behavioral and electrophysiological studies suggest that while specific voice reinstatement (i.e., same speaker) often appears to facilitate word memory even without attention to voice at study, the presence of a partial benefit of similar voices between study and test is less clear. In terms of explicit memory experiments utilizing unfamiliar voices, encoding methods appear to play a pivotal role. Voice congruency effects have been found when voice is specifically attended at study (i.e., when relatively shallow, perceptual encoding takes place). These behavioral findings coincide with neural indices of memory performance such as the parietal old/new recollection effect and the late right frontal effect. The former distinguishes between correctly identified old words and correctly identified new words, and reflects voice congruency only when voice is attended at study. Characterization of the latter likely depends upon voice memory, rather than word memory. There is also evidence to suggest that voice effects can be found in implicit memory paradigms. However, the presence of voice effects appears to depend greatly on the task employed. Using a word identification task, perceptual similarity between study and test conditions is, like for explicit memory tests, crucial. In addition, the type of noise employed appears to have a differential effect. While voice effects have been observed when white noise is used at both study and test, using multi-talker babble does not confer the same results. In terms of neuroimaging research modulations, characterization of an implicit memory effect

  7. PROGRESS TOWARDS MODELING OF FISCHER TROPSCH SYNTHESIS IN A SLURRY BUBBLE COLUMN REACTOR

    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen; Tami Grimmett; Anastasia M. Gandrik; Steven P. Antal

    2010-11-01

    The Hybrid Energy Systems Testing (HYTEST) Laboratory is being established at the Idaho National Laboratory to develop and test hybrid energy systems with the principal objective to safeguard U.S. Energy Security by reducing dependence on foreign petroleum. A central component of the HYTEST is the slurry bubble column reactor (SBCR) in which the gas-to-liquid reactions will be performed to synthesize transportation fuels using the Fischer Tropsch (FT) process. SBCRs are cylindrical vessels in which gaseous reactants (for example, synthesis gas or syngas) is sparged into a slurry of liquid reaction products and finely dispersed catalyst particles. The catalyst particles are suspended in the slurry by the rising gas bubbles and serve to promote the chemical reaction that converts syngas to a spectrum of longer chain hydrocarbon products, which can be upgraded to gasoline, diesel or jet fuel. These SBCRs operate in the churn-turbulent flow regime which is characterized by complex hydrodynamics, coupled with reacting flow chemistry and heat transfer, that effect reactor performance. The purpose of this work is to develop a computational multiphase fluid dynamic (CMFD) model to aid in understanding the physico-chemical processes occurring in the SBCR. Our team is developing a robust methodology to couple reaction kinetics and mass transfer into a four-field model (consisting of the bulk liquid, small bubbles, large bubbles and solid catalyst particles) that includes twelve species: (1) CO reactant, (2) H2 reactant, (3) hydrocarbon product, and (4) H2O product in small bubbles, large bubbles, and the bulk fluid. Properties of the hydrocarbon product were specified by vapor liquid equilibrium calculations. The absorption and kinetic models, specifically changes in species concentrations, have been incorporated into the mass continuity equation. The reaction rate is determined based on the macrokinetic model for a cobalt catalyst developed by Yates and Satterfield [1]. The

  8. Hydroprocessing of Fischer-Tropsch biowaxes to second-generation biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Schablitzky, Harald Walter; Hafner, C. [OMV Refining and Marketing, Centre of Excellence-Fuels, Innovation and Quality, Schwechat (Austria); Lichtscheidl, J.; Hutter, K. [OMV Refining and Marketing, New Technology, Schwechat (Austria); Rauch, R. [Bioenergy, Graz (Austria); Hofbauer, H. [Bioenergy, Graz (Austria); Vienna University of Technology, Institute of Chemical Engineering, Vienna (Austria)

    2011-03-15

    Upgrading of Fischer-Tropsch (FT) biowaxes to second-generation biofuels via hydroprocessing is the final step for increasing the fuel amount of the overall biomass conversion route: gasification of lignocellulosic biomass, FT synthesis, and hydroprocessing. The typical FT product portfolio consists of high molecular weight paraffinic waxes as the main product and FT fuels in the diesel and naphtha boiling range. OMV's objective and contribution to the project focus on achieving coprocessing of FT biowaxes with fossil feedstock using existing hydrotreating plants of crude oil refineries. Various test runs have been examined with a conventional refining catalyst under mild conditions (380-390 C, 5.8 MPa; WHSV, 0.7-1.3 h{sup -1}) in a pilot plant. Pure FT biowax is converted to gases, fuels, and an oil/waxy residue in a fixed-bed reactor with a porous catalyst layer technology. The presence of hydrogen in the reaction chamber reduces the fast deactivation of the catalyst caused by the formation of a coke layer around the catalyst particle surface and saturates cracked hydrocarbon fragments. Another approach is the creation of synthetic biodiesel components with excellent fuel properties for premium fuel application. Basically, premium diesel fuel differs from standard diesel quality by cetane number and cold flow properties. Hydroprocessed synthetic biodiesel (HPFT diesel) has compared to conventional diesel advantages in many aspects. Depending on the catalyst selected, premium diesel quality can be obtained by shifting cold flow operability properties of HPFT fuels to a range capable even under extreme cold conditions. In addition, a high-quality kerosene fraction is obtained to create bio jet fuels with an extremely deep freezing point, as low as -80 C. The isomerization degree, as well as the carbon number distribution of high paraffinic profile, and the branching degree have a major impact on the cold flow properties and cetane number. FT diesel has

  9. Parametric study of Fischer-Tropsch synthesis in supercritical phase carbon dioxide

    Science.gov (United States)

    Gautam, Jitendra

    The results from studies on Fischer Tropsch synthesis wherein syngas was dissolved in CO2 are presented. The syngas generally used was typical of that obtained from coal gasification, i.e. CO:H2 of one. Under these conditions Co-based catalysts without any water gas shift catalyst does not perform well while Fe -- based catalysts have been found to be useful. However, the Fe based catalysts have a propensity towards CO2 selectivity via the primary FT reaction, Boudouard reaction and the water gas shift reaction. The use of CO2 as a solvent was found to suppress the CO2 and CH4 selectivity while enhancing the hydrocarbon selectivity and CO conversion when FT synthesis was conducted using coal derived syngas on Fe-Zn-K catalysts. The effects were found to be significantly pronounced at pressures higher than or equal to 1200 psig. It should be noted that CO2 is supercritical at pressures higher than 1070 psig and 31.4 °C. The effect of CO2 partial pressure, reactor pressure, reaction temperature, catalyst loading and H 2:CO ratio in syngas on the liquid product distribution was evaluated. Some of the notable findings include product tenability by varying temperature and pressure as well as varying the CO2 partial pressure and the syngas composition. Increasing the reactor pressure was found to favor longer chain growth. In addition, it was noted that the ratio between CO2:syngas in the reaction mixture is an important factor in the liquid product distribution. A higher value of the ratio is seen to favor hydrocarbon synthesis, while a lower value of the ratio favors oxygenate production particularly pentanols and butanols. In addition, the data on the once through fractionation of the products utilizing the solubilities in supercritical CO2 and pressure tuning were encouraging. It was found that the products can be easily fractionated into narrow carbon chain length distributions downstream of the reactor by simply reducing the pressures in each collection vessel. It

  10. Determination of kinetics of the karl Fischer reaction based on coulometry and true potentiometry.

    Science.gov (United States)

    Cedergren, A

    1996-03-01

    A new measurement technique based on a combination of coulometry and zero-current potentiometry is described for determination of the kinetics of rapidly reacting Karl Fischer (KF) reagents. This makes it possible to determine the order as well as the rate constant for large variations in the concentrations of iodine and water present during a titration. It was shown that for imidazole-based methanolic reagents exposed to a large variation in the concentration of water, the KF reaction is first order with respect to iodine, sulfur dioxide, and water only for reagents in which the concentration of nonprotonated imidazole is very low. The rate constant determined for such a reagent (1 M imidazole, 0.8 M sulfur dioxide, 0.1 M iodine) was equal to that reported earlier in the literature. Regions showing first-order kinetics were also found for low concentrations of water when imidazole concentrations up to 2 mol/L were used, provided that these reagents had a quotient [Im](free)/[ImH(+)] around 4. In the interval 2-8 mol/L of imidazole, the order of the reaction with respect to iodine was, in most cases, one-half, while it was changed to between one-half and one with respect to water. The rate of the KF reaction was found to increase by nearly 5 orders of magnitude for a reagent in which the concentration of nonprotonated imidazole was increased from 0 (rate constant equal to 2.6 × 10(3) L(2) mol(-)(2) s(-)(1)) to about 7 mol/L. For most of these reagents, a recovery rate close to 100% was attained. A high concentration of nonprotonated imidazole in combination with a high concentration of sulfur dioxide could, however, lead to a change in stoichiometry of the KF reaction when larger amounts of water were determined (250 μg of water added to 3.4 mL of reagent solution). A reaction scheme is proposed which might explain this change in stoichiometry observed for some reagent compositions. By use of the described most rapidly reacting reagents, it was shown to be

  11. Coulometric Karl Fischer titration of trace water in diaphragm-free cells.

    Science.gov (United States)

    Larsson, William; Cedergren, Anders

    2005-03-15

    Factors influencing the accuracy and precision for diaphragm-free Karl Fischer coulometric determinations of low mug-amounts of water have been studied using the Metrohm 756 (pulsed current) coulometer and eight different types of commercial coulometric reagents and some modifications of these. As in the case of diaphragm-free coulometric titration of large amounts of water, the positive errors, due to the formation of oxidizable reduction products (of sulfur dioxide) in the cathode reaction (besides hydrogen), were found to be minimized by the use of highest possible pulse current (in the range 100-400mA) in combination with the fastest possible titration rate. Most accurate (102-103%) and precise results (typical relative standard deviation 1.8%) were obtained for reagents containing very large concentrations of imidazole in combination with the presence of modifiers like hexanol, chloroform and propylene glycol (i.e. the HYDRA-POINT reagents). Similar results were obtained when this type of reagent was mixed 60/40 with xylene according to the ASTM recommendation for water determinations in petroleum products like crude and lubricating oils. Addition of decanol to this type of reagent mixture was found to reduce the influence from the oxidative reduction products significantly. A reduction of the error from 3.6% relative to 1.6% was achieved by addition of 9% (v/v) of decanol to a 60/40 reagent mixture of HYDRA-POINT Coulometric Gen (containing hexanol as modifier) and xylene. For larger concentrations of decanol the pulse current had to be lowered to 100mA and this might explain why no further improvement was observed. An additional attempt to minimize the interference by lowering the concentration of sulfur dioxide in the reagents gave no significant effect. However, by means of a home-built computer-controlled coulometric instrumentation based on continuous instead of pulsed current (including a large cathodic current density) it was possible to achieve

  12. Comparative 90-day dietary study of paraffin wax in Fischer-344 and Sprague-Dawley rats.

    Science.gov (United States)

    Griffis, L C; Twerdok, L E; Francke-Carroll, S; Biles, R W; Schroeder, R E; Bolte, H; Faust, H; Hall, W C; Rojko, J

    2010-01-01

    Highly refined mineral hydrocarbons (MHCs) such as low melting point paraffin wax (LMPW) and low viscosity white oils can cause inflammatory changes in the liver and mesenteric lymph nodes (MLNs) of the Fischer-344 (F-344) rat. In contrast, only minimal MLN changes are seen in the Sprague-Dawley (S-D) rat with no changes in the liver. In this study, the response of female F-344 and S-D rats was compared after 90days dietary treatment with 0%, 0.2% or 2% LMPW. Effects in the F-344 rats were significantly greater than in the S-D rats: increased liver and splenic weights and inflammatory changes (hepatic microgranulomas) in these tissues were observed only in the F-344 rats. Microgranulomas in the MLNs were observed in both strains but the effects were substantially greater in the F-344 rats. Cellular markers of inflammation were examined in a subset of rats from each group using immunohistochemical staining. An increase in staining for CD3 (T-cells), CD8a (suppresser/cytotoxic T-cells) and CD4 (helper T-cells) correlated with an increase in lymphoid cells in the livers of treated F-344 rats. The majority of macrophages in the hepatic microgranulomas of treated F-344 rats were negative for the ED2 marker, indicating a likely origin from non-resident macrophages. Electron microscopy showed Kupffer cell hypertrophy and hyperplasia in treated F-344 rats. However, lysozyme staining (indicating activation of epithelioid macrophages) decreased with increasing granuloma size. Non-ED2 expressing cells may have been recruited but not sufficiently activated to be lysozyme positive. Inflammatory changes in the cardiac mitral valve noted in previous studies of LMPW were also seen in the F-344 rats in this study but not in the S-D rats. Chemical analysis showed that MHC accumulated in livers from treated F-344 but not S-D rats and the concentration was more than 2-fold greater in MLNs from the F-344 than from the S-D rats. The F-344 appears to be more immunologically sensitive to

  13. Moessbauer study of iron-carbide growth and Fischer-Tropsch activity

    Energy Technology Data Exchange (ETDEWEB)

    Rao, K.R.P.M.; Huggins, F.E.; Huffman, G.P. [Univ. of Kentucky, Lexington, (United States)] [and others

    1995-12-31

    There is a need to establish a correlation between the Fischer-Tropsch (FT) activity of an iron-based catalyst and the catalyst phase during FT synthesis. The nature of iron phases formed during activation and FT synthesis is influenced by the nature of the gas and pressure apart from other parameters like temperature, flow rate etc., used for activation. Moessbauer investigations of iron-based catalysts subjected to pretreatment at two different pressures in gas atmospheres containing mixtures of CO, H{sub 2}, and He have been carried out. Studies on UCI 1185-57 (64%Fe{sub 2}O{sub 3}/5%CuO/1%K{sub 2}O/30% Kaolin) catalyst indicate that activation of the catalyst in CO at 12 atms. leads to the formation of 100% magnetite and the magnetite formed gets rapidly converted to at least 90% of {chi}-Fe{sub 5}C{sub 2} during activation. The FT activity was found to be good at 70-80% of (H{sub 2}+CO) conversion. On the other hand, activation. The FT activity was found to be good at 70-80% of (H{sub 2}+CO) conversion. On the other hand, activation of the catalyst in synthesis gas at 12 atms. leads to formation of Fe{sub 3}O{sub 4} and it gets sluggishly converted to {chi}-Fe{sub 5}C{sub 2} and {epsilon}-Fe{sub 2.2}C during activation and both continue to grow slowly during FT synthesis. FT activity is found to be poor. Pretreatment of the catalyst, 100fe/3.6Si/0.71K at a low pressure of 1 atms. in syngas gave rise to the formation of {chi}-Fe{sub 5}C{sub 2} and good FT activity. On the other hand, pretreatment of the catalyst, 100Fe/3.6Si/0.71K at a relatively high pressure of 12 atms. in syngas did not give rise to the formation any carbide and FT activity was poor.

  14. Optical memory

    Science.gov (United States)

    Mao, Samuel S; Zhang, Yanfeng

    2013-07-02

    Optical memory comprising: a semiconductor wire, a first electrode, a second electrode, a light source, a means for producing a first voltage at the first electrode, a means for producing a second voltage at the second electrode, and a means for determining the presence of an electrical voltage across the first electrode and the second electrode exceeding a predefined voltage. The first voltage, preferably less than 0 volts, different from said second voltage. The semiconductor wire is optically transparent and has a bandgap less than the energy produced by the light source. The light source is optically connected to the semiconductor wire. The first electrode and the second electrode are electrically insulated from each other and said semiconductor wire.

  15. Fuzzy model prediction of Co (Ⅲ)/Al2O3 catalytic behavior in Fischer-Tropsch synthesis

    Institute of Scientific and Technical Information of China (English)

    Mohammad Ali Takassi; Mahdi Koolivand Salooki; Morteza Esfandyari

    2011-01-01

    The application of Co (Ⅲ)/Al2O3 catalyst in Fischer-Tropsch synthesis (FTS) was studied in a wide range of synthesis gas conversions and compared with Fuzzy Simulation results.Present study applies fuzzy model to predicting the product composition of CH4,CO2 and CO in Fischer-Tropsch process for natural gas synthesis,in which the input vector was 4-dimension including four variables (operating pressure,operating temperature,time and CO/H2 ratio) of 70 different experim.ents and the output product is a composition of CO2,CO and CH4.The Mamdani algorithm has been applied to the training of the fuzzy system and the test set was used to evaluate the performance of the system including R2,ARE,AARE and SD.The results demonstrated that the predicted values from the model were in good consistency with the experimental data.The work indicates how fuzzy inference system (FIS),as a promising predicting technique,would be effectively used in FTS.

  16. Comparison between amperometric and true potentiometric end-point detection in the determination of water by the Karl Fischer method.

    Science.gov (United States)

    Cedergren, A

    1974-06-01

    A rapid and sensitive method using true potentiometric end-point detection has been developed and compared with the conventional amperometric method for Karl Fischer determination of water. The effect of the sulphur dioxide concentration on the shape of the titration curve is shown. By using kinetic data it was possible to calculate the course of titrations and make comparisons with those found experimentally. The results prove that the main reaction is the slow step, both in the amperometric and the potentiometric method. Results obtained in the standardization of the Karl Fischer reagent showed that the potentiometric method, including titration to a preselected potential, gave a standard deviation of 0.001(1) mg of water per ml, the amperometric method using extrapolation 0.002(4) mg of water per ml and the amperometric titration to a pre-selected diffusion current 0.004(7) mg of water per ml. Theories and results dealing with dilution effects are presented. The time of analysis was 1-1.5 min for the potentiometric and 4-5 min for the amperometric method using extrapolation.

  17. Detection of Low Level Microwave Radiation Induced Deoxyribonucleic Acid Damage Vis-à-vis Genotoxicity in Brain of Fischer Rats

    Science.gov (United States)

    Deshmukh, Pravin Suryakantrao; Megha, Kanu; Banerjee, Basu Dev; Ahmed, Rafat Sultana; Chandna, Sudhir; Abegaonkar, Mahesh Pandurang; Tripathi, Ashok Kumar

    2013-01-01

    Background: Non-ionizing radiofrequency radiation has been increasingly used in industry, commerce, medicine and especially in mobile phone technology and has become a matter of serious concern in present time. Objective: The present study was designed to investigate the possible deoxyribonucleic acid (DNA) damaging effects of low-level microwave radiation in brain of Fischer rats. Materials and Methods: Experiments were performed on male Fischer rats exposed to microwave radiation for 30 days at three different frequencies: 900, 1800 and 2450 MHz. Animals were divided into 4 groups: Group I (Sham exposed): Animals not exposed to microwave radiation but kept under same conditions as that of other groups, Group II: Animals exposed to microwave radiation at frequency 900 MHz at specific absorption rate (SAR) 5.953 × 10−4 W/kg, Group III: Animals exposed to 1800 MHz at SAR 5.835 × 10−4 W/kg and Group IV: Animals exposed to 2450 MHz at SAR 6.672 × 10−4 W/kg. At the end of the exposure period animals were sacrificed immediately and DNA damage in brain tissue was assessed using alkaline comet assay. Results: In the present study, we demonstrated DNA damaging effects of low level microwave radiation in brain. Conclusion: We concluded that low SAR microwave radiation exposure at these frequencies may induce DNA strand breaks in brain tissue. PMID:23833433

  18. How users experience great products

    NARCIS (Netherlands)

    Ortiz Nicolas, J.C.; Aurisicchio, M.; Desmet, P.M.A.

    2013-01-01

    This study reports qualitative research about how users experience great products. Eighteen interviews were conducted in which participants were asked to bring along a ‘great’ product that they own. During the interviews participants explained why they consider a product great and how they experienc

  19. Great Explorers to the East.

    Science.gov (United States)

    Baker, Rosalie F., Ed.; Baker, Charles F. III, Ed.

    1990-01-01

    This issue of "Calliope," a world history magazine for young people is devoted to "Great Explorers of the East" and features articles on famous explorers of the eastern hemisphere. The following articles are included: "Ancient Egyptian Mariners"; "Alexander: The Great Reconciler"; "Marco Polo:…

  20. What Caused the Great Depression?

    Science.gov (United States)

    Caldwell, Jean; O'Driscoll, Timothy G.

    2007-01-01

    Economists and historians have struggled for almost 80 years to account for the American Great Depression, which began in 1929 and lasted until the early years of World War II. In this article, the authors discuss three major schools of thought on the causes of the Great Depression and the long failure of the American economy to return to full…

  1. Great Explorers to the East.

    Science.gov (United States)

    Baker, Rosalie F., Ed.; Baker, Charles F. III, Ed.

    1990-01-01

    This issue of "Calliope," a world history magazine for young people is devoted to "Great Explorers of the East" and features articles on famous explorers of the eastern hemisphere. The following articles are included: "Ancient Egyptian Mariners"; "Alexander: The Great Reconciler"; "Marco Polo: Describing the World"; "By Water to India";…

  2. Rethinking China's new great wall

    National Research Council Canada - National Science Library

    Ma, Zhijun; Melville, David S; Liu, Jianguo; Chen, Ying; Yang, Hongyan; Ren, Wenwei; Zhang, Zhengwang; Piersma, Theunis; Li, Bo

    2014-01-01

    ... enclosed by thousands of kilometers of seawalls, whose length exceeds that of China’s famous ancient “Great Wall” (see photos and map). This new “Great Wall,” covering 60% of the total length of coast-line along mainland China...

  3. Structural, Synaptic, and Epigenetic Dynamics of Enduring Memories

    Directory of Open Access Journals (Sweden)

    Ossama Khalaf

    2016-01-01

    Full Text Available Our memories are the records of the experiences we gain in our everyday life. Over time, they slowly transform from an initially unstable state into a long-lasting form. Many studies have been investigating from different aspects how a memory could persist for sometimes up to decades. In this review, we highlight three of the greatly addressed mechanisms that play a central role for a given memory to endure: the allocation of the memory to a given neuronal population and what brain areas are recruited for its storage; the structural changes that underlie memory persistence; and finally the epigenetic control of gene expression that might regulate and support memory perseverance. Examining such key properties of a memory is essential towards a finer understanding of its capacity to last.

  4. Evaluating operating system vulnerability to memory errors.

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Kurt Brian; Bridges, Patrick G. (University of New Mexico); Pedretti, Kevin Thomas Tauke; Mueller, Frank (North Carolina State University); Fiala, David (North Carolina State University); Brightwell, Ronald Brian

    2012-05-01

    Reliability is of great concern to the scalability of extreme-scale systems. Of particular concern are soft errors in main memory, which are a leading cause of failures on current systems and are predicted to be the leading cause on future systems. While great effort has gone into designing algorithms and applications that can continue to make progress in the presence of these errors without restarting, the most critical software running on a node, the operating system (OS), is currently left relatively unprotected. OS resiliency is of particular importance because, though this software typically represents a small footprint of a compute node's physical memory, recent studies show more memory errors in this region of memory than the remainder of the system. In this paper, we investigate the soft error vulnerability of two operating systems used in current and future high-performance computing systems: Kitten, the lightweight kernel developed at Sandia National Laboratories, and CLE, a high-performance Linux-based operating system developed by Cray. For each of these platforms, we outline major structures and subsystems that are vulnerable to soft errors and describe methods that could be used to reconstruct damaged state. Our results show the Kitten lightweight operating system may be an easier target to harden against memory errors due to its smaller memory footprint, largely deterministic state, and simpler system structure.

  5. What makes a ‘National’ War Memorial? The Case of the Australian Ex-Prisoners of War Memorial

    Directory of Open Access Journals (Sweden)

    Lachlan Grant

    2006-03-01

    Full Text Available The Australian Ex-Prisoners of War Memorial was unveiled in Ballarat to great fanfare in February 2004. Struggling to overcome serious setbacks in order to raise the necessary funds to construct the $2 million memorial over more than a period of four years, the memorial, listing the names of all Australian prisoners of war from all conflicts was judged by the Federal Government to be nothing but a ‘local’ memorial rather than a ‘national’ memorial. The article investigates whether this issue is at all associated with the ambiguity and difficulty of incorporating prisoners of war into the Anzac legend or whether there were other factors at hand deciding the official ‘national’ status of the first war memorial to list the names of all Australian prisoners of war. The importance of this issue reveals how government bureaucracy and party politics can influence the future and potential public significance of a war memorial.

  6. Memory and Study

    Institute of Scientific and Technical Information of China (English)

    沈园

    1996-01-01

    Of all the myths that surround memory, the most damaging is that it is agift. That is quite untrue. Memory is a skill; and like any skill its performancedepends on application, on practice, and on regular training. Everyone poten-tially has a first-class memory; and everyone can train their memory, and there-

  7. Memory, microprocessor, and ASIC

    CERN Document Server

    Chen, Wai-Kai

    2003-01-01

    System Timing. ROM/PROM/EPROM. SRAM. Embedded Memory. Flash Memories. Dynamic Random Access Memory. Low-Power Memory Circuits. Timing and Signal Integrity Analysis. Microprocessor Design Verification. Microprocessor Layout Method. Architecture. ASIC Design. Logic Synthesis for Field Programmable Gate Array (EPGA) Technology. Testability Concepts and DFT. ATPG and BIST. CAD Tools for BIST/DFT and Delay Faults.

  8. Memory Remains: Understanding Collective Memory in the Digital Age

    CERN Document Server

    García-Gavilanes, Ruth; Tsvetkova, Milena; Yasseri, Taha

    2016-01-01

    Recently developed information communication technologies, particularly the Internet, have affected how we, both as individuals and as a society, create, store, and recall information. Internet also provides us with a great opportunity to study memory using transactional large scale data, in a quantitative framework similar to the practice in statistical physics. In this project, we make use of online data by analysing viewership statistics of Wikipedia articles on aircraft crashes. We study the relation between recent events and past events and particularly focus on understanding memory triggering patterns. We devise a quantitative model that explains the flow of viewership from a current event to past events based on similarity in time, geography, topic, and the hyperlink structure of Wikipedia articles. We show that on average the secondary flow of attention to past events generated by such remembering processes is larger than the primary attention flow to the current event. We are the first to report thes...

  9. LIQUID PHASE FISCHER-TROPSCH (III & IV) DEMONSTRATION IN THE LAPORTE ALTERNATIVE FUELS DEVELOPMENT UNIT. Final Topical Report. Volume I/II: Main Report. Task 1: Engineering Modifications (Fischer-Tropsch III & IV Demonstration) and Task 2: AFDU Shakedown, Operations, Deactivation (Shut-Down) and Disposal (Fischer-Tropsch III & IV Demonstration).

    Energy Technology Data Exchange (ETDEWEB)

    Bharat L. Bhatt

    1999-06-01

    Slurry phase Fischer-Tropsch technology was successfully demonstrated in DOE's Alternative Fuels Development Unit (AFDU) at LaPorte, Texas. Earlier work at LaPorte, with iron catalysts in 1992 and 1994, had established proof-of-concept status for the slurry phase process. The third campaign (Fischer-Tropsch III), in 1996, aimed at aggressively extending the operability of the slurry reactor using a proprietary cobalt catalyst. Due to an irreversible plugging of catalyst-wax separation filters as a result of unexpected catalyst fines generation, the operations had to be terminated after seven days on-stream. Following an extensive post-run investigation by the participants, the campaign was successfully completed in March-April 1998, with an improved proprietary cobalt catalyst. These runs were sponsored by the U. S. Department of Energy (DOE), Air Products & Chemicals, Inc., and Shell Synthetic Fuels, Inc. (SSFI). A productivity of approximately 140 grams (gm) of hydrocarbons (HC)/ hour (hr)-liter (lit) of expanded slurry volume was achieved at reasonable system stability during the second trial (Fischer-Tropsch IV). The productivity ranged from 110-140 at various conditions during the 18 days of operations. The catalyst/wax filters performed well throughout the demonstration, producing a clean wax product. For the most part, only one of the four filter housings was needed for catalyst/wax filtration. The filter flux appeared to exceed the design flux. A combination of use of a stronger catalyst and some innovative filtration techniques were responsible for this success. There was no sign of catalyst particle attrition and very little erosion of the slurry pump was observed, in contrast to the Fischer-Tropsch III operations. The reactor operated hydrodynamically stable with uniform temperature profile and gas hold-ups. Nuclear density and differential pressure measurements indicated somewhat higher than expected gas hold-up (45 - 50 vol%) during Fischer

  10. Non-volatile memories

    CERN Document Server

    Lacaze, Pierre-Camille

    2014-01-01

    Written for scientists, researchers, and engineers, Non-volatile Memories describes the recent research and implementations in relation to the design of a new generation of non-volatile electronic memories. The objective is to replace existing memories (DRAM, SRAM, EEPROM, Flash, etc.) with a universal memory model likely to reach better performances than the current types of memory: extremely high commutation speeds, high implantation densities and retention time of information of about ten years.

  11. Adaptive associative memories capable of pattern segmentation.

    Science.gov (United States)

    Ma, Q

    1996-01-01

    This paper presents an adaptive type of associative memory (AAM) that can separate patterns from composite inputs which might be degraded by deficiency or noise and that can recover incomplete or noisy single patterns. The behavior of AAM is analyzed in terms of stability, giving the stable solutions (results of recall), and the recall of spurious memories (the undesired solutions) is shown to be greatly reduced compared with earlier types of associative memory that can perform pattern segmentation. Two conditions that guarantee the nonexistence of undesired solutions are also given. Results of computer experiments show that the performance of AAM is much better than that of the earlier types of associative memory in terms of pattern segmentation and pattern recovery.

  12. Mn promotion effects in Co/TiO2 Fischer-Tropsch catalysts as investigated by XPS and STEM-EELS

    NARCIS (Netherlands)

    Morales, F; de Groot, FMF|info:eu-repo/dai/nl/08747610X; Gijzeman, OLJ|info:eu-repo/dai/nl/073464708; Mens, A|info:eu-repo/dai/nl/313707065; Stephan, O; Weckhuysen, BM|info:eu-repo/dai/nl/285484397

    2005-01-01

    The addition of small amounts of Mn to a Co/TiO2 catalyst affects the catalytic performance in the Fischer-Tropsch synthesis (FTS) by increasing the activity and suppressing the CH4 yield. These variations in the catalyst selectivity are due to Mn promotion effects that influence the final catalyst

  13. Six-flow operations for catalyst development in Fischer-Tropsch synthesis: Bridging the gap between high-throughput experimentation and extensive product evaluation

    NARCIS (Netherlands)

    Sartipi, S.; Jansma, H.; Bosma, D.; Boshuizen, B.; Makkee, M.; Gascon, J.; Kapteijn, F.

    2013-01-01

    Design and operation of a “six-flow fixed-bed microreactor” setup for Fischer-Tropsch synthesis (FTS) is described. The unit consists of feed and mixing, flow division, reaction, separation, and analysis sections. The reactor system is made of five heating blocks with individual temperature controll

  14. Verbal memory and menopause.

    Science.gov (United States)

    Maki, Pauline M

    2015-11-01

    Midlife women frequently report memory problems during the menopausal transition. Recent studies validate those complaints by showing significant correlations between memory complaints and performance on validated memory tasks. Longitudinal studies demonstrate modest declines in verbal memory during the menopausal transition and a likely rebound during the postmenopausal stage. Clinical studies that examine changes in memory following hormonal withdrawal and add-back hormone therapy (HT) demonstrate that estradiol plays a critical role in memory. Although memory changes are frequently attributed to menopausal symptoms, studies show that the memory problems occur during the transition even after controlling for menopausal symptoms. It is well established that self-reported vasomotor symptoms (VMS) are unrelated to objective memory performance. However, emerging evidence suggests that objectively measured VMS significantly correlate with memory performance, brain activity during rest, and white matter hyperintensities. This evidence raises important questions about whether VMS and VMS treatments might affect memory during the menopausal transition. Unfortunately, there are no clinical trials to inform our understanding of how HT affects both memory and objectively measured VMS in women in whom HT is indicated for treatment of moderate to severe VMS. In clinical practice, it is helpful to normalize memory complaints, to note that evidence suggests that memory problems are temporary, and to counsel women with significant VMS that memory might improve with treatment.

  15. The Great Cacti: Ethnobotany & Biogeography

    Directory of Open Access Journals (Sweden)

    David A. Hooper

    2010-08-01

    Full Text Available Review of The Great Cacti: Ethnobotany & Biogeography. David Yetman. 2007. The University of Arizona, Tucson. Pp. 320, 366 color photographs, 17 maps. $59.95 (cloth. ISBN 9780816524310.

  16. Juyongguan on the Great Wall

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Juyongguan Pass on the Great Wall,one ofthe most important strategic passes of the oldcapital Beijing,is now repaired and a goodplace for tourists to see ancient Chinesemilitary and cultural facilities,as well asbeautiful local scenery.

  17. Critical Realism in Great Expectations

    Institute of Scientific and Technical Information of China (English)

    姚雪莲

    2014-01-01

    Great Expectations is an important work by English novelist Dickens.His novels not only reflect the life experience of a whole generation genuinely,but also disclose the social reality vividly in England in the middle 19th century.Its depth and width go beyond most of the works of his contemporaries.Great Expectations is the excellent novel of critical realism in the later period of Dickens.It describes the de-velopment of Pip’s grown-up and the disillusion of his“great expectations”.Educated by the reality,he came to realize what he pursued in the Vanity Fair was not valuable at all.So as to see clearer the great power of critical realism in Dickens’works and thus can understand the no-vel,this thesis analyzes the hero’s character development and the influential factors upon the formation of his character.

  18. "I Climbed the Great Wall"

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    I finally climbed the Great Wall, A dream of my childhood; my heart is filled with pleasure at the indescribable beauty of the Wall. China’s ancient civilization is best documented by the grandeur of the Wall.

  19. Great Lakes Environmental Research Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — NOAA-GLERL and its partners conduct innovative research on the dynamic environments and ecosystems of the Great Lakes and coastal regions to provide information for...

  20. Great Lakes Initiative (GLI) Clearinghouse

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Great Lakes Initiative Toxicity Data Clearinghouse is a central location for information on criteria, toxicity data, exposure parameters and other supporting...

  1. The Sixth Great Mass Extinction

    Science.gov (United States)

    Wagler, Ron

    2012-01-01

    Five past great mass extinctions have occurred during Earth's history. Humanity is currently in the midst of a sixth, human-induced great mass extinction of plant and animal life (e.g., Alroy 2008; Jackson 2008; Lewis 2006; McDaniel and Borton 2002; Rockstrom et al. 2009; Rohr et al. 2008; Steffen, Crutzen, and McNeill 2007; Thomas et al. 2004;…

  2. GREAT Process Modeller user manual

    OpenAIRE

    Rueda, Urko; España, Sergio; Ruiz, Marcela

    2015-01-01

    This report contains instructions to install, uninstall and use GREAT Process Modeller, a tool that supports Communication Analysis, a communication-oriented business process modelling method. GREAT allows creating communicative event diagrams (i.e. business process models), specifying message structures (which describe the messages associated to each communicative event), and automatically generating a class diagram (representing the data model of an information system that would support suc...

  3. Photography as object and resource of memory
    A fotografia como objeto e recurso de memória

    OpenAIRE

    Etienne Samain; Adair Felizardo

    2007-01-01

    With the rise of digital photography, its ease, potentials and weaknesses, we have become more and more liable to the iconographic forgetting of our own memory, our photographic memory. This essay intends to discuss the value and the use of photography as one of the great memory-bearing instruments, own memory, memory to be clarified, interpreted, remembered. Com o advento da fotografia digital, suas facilidades, potencialidades e fragilidades, ficamos suscetíveis ao esquecimento iconográfico...

  4. Exponential lifetime improvement in topological quantum memories

    Science.gov (United States)

    Bardyn, Charles-Edouard; Karzig, Torsten

    2016-09-01

    We propose a simple yet efficient mechanism for passive error correction in topological quantum memories. Our scheme relies on driven-dissipative ancilla systems which couple to local excitations (anyons) and make them "sink" in energy, with no required interaction among ancillae or anyons. Through this process, anyons created by some thermal environment end up trapped in potential "trenches" that they themselves generate, which can be interpreted as a "memory foam" for anyons. This self-trapping mechanism provides an energy barrier for anyon propagation and removes entropy from the memory by favoring anyon recombination over anyon separation (responsible for memory errors). We demonstrate that our scheme leads to an exponential increase of the memory-coherence time with system size L , up to an upper bound Lmax, which can increase exponentially with Δ /T , where T is the temperature and Δ is some energy scale defined by potential trenches. This results in a double exponential increase of the memory time with Δ /T , which greatly improves over the Arrhenius (single-exponential) scaling found in typical quantum memories.

  5. Natural disasters between memory and oblivion

    Science.gov (United States)

    Crescimbene, M.; La Longa, F.; Lanza, T.

    2012-04-01

    The last decades of the twentieth century and the beginning of the new millennium have been marked by a strong focus on the past and, consequently, a proliferation of studies on memory. Perhaps this great attention to memory implies a new way of thinking and experiencing time and space, two categories that deeply changed by the phenomenon of cultural globalization (Huyssen, 2003). If it is true that with new technologies, space and time have been dramatically compressed, it is also true that the horizons of our imagination have expanded to dimensions of space and time which are able to cross the boundaries of a locally circumscribed vision. So our past and our memory no longer have clear and delimited boundaries which were established by a tradition with local and national roots within specific geographical borders. The revival of studies on memory has included large Italian catastrophes occurred in the last centuries. Several initiatives, researches, exhibitions and commemorations wanted to remember these great catastrophes of our country. What is the relationship between these initiatives and the reduction of risk? What relationships are there between memory, forgetting and risk? On the issue of risk reduction the provocative phrase of Pierre Nora fits well: "We talk about memory because it no longer exists "? (Pierre Nora, Les Lieux de mémoire, Gallimard 1997). A direction to work on is indicated by Aleida Assmann (1999) that associates the idea of crisis of memory with the crisis of "living memory", that is linked to the disappearance of the eyewitnesses of the greatest tragedies of the twentieth century. When the generations who lived through L'Aquila earthquake on 6 April 2009 will die, the memory of the earthquake will vanish with them? To answer these questions and to propose communication and educational strategies capable of persisting the passage of generations, this work explores an interdisciplinary point of view, which takes into account recent

  6. Associative memory realized by a reconfigurable memristive Hopfield neural network.

    Science.gov (United States)

    Hu, S G; Liu, Y; Liu, Z; Chen, T P; Wang, J J; Yu, Q; Deng, L J; Yin, Y; Hosaka, Sumio

    2015-06-25

    Although synaptic behaviours of memristors have been widely demonstrated, implementation of an even simple artificial neural network is still a great challenge. In this work, we demonstrate the associative memory on the basis of a memristive Hopfield network. Different patterns can be stored into the memristive Hopfield network by tuning the resistance of the memristors, and the pre-stored patterns can be successfully retrieved directly or through some associative intermediate states, being analogous to the associative memory behaviour. Both single-associative memory and multi-associative memories can be realized with the memristive Hopfield network.

  7. Reductions in aircraft particulate emissions due to the use of Fischer-Tropsch fuels

    Science.gov (United States)

    Beyersdorf, A. J.; Timko, M. T.; Ziemba, L. D.; Bulzan, D.; Corporan, E.; Herndon, S. C.; Howard, R.; Miake-Lye, R.; Thornhill, K. L.; Winstead, E.; Wey, C.; Yu, Z.; Anderson, B. E.

    2013-06-01

    The use of alternative fuels for aviation is likely to increase due to concerns over fuel security, price stability and the sustainability of fuel sources. Concurrent reductions in particulate emissions from these alternative fuels are expected because of changes in fuel composition including reduced sulfur and aromatic content. The NASA Alternative Aviation Fuel Experiment (AAFEX) was conducted in January-February 2009 to investigate the effects of synthetic fuels on gas-phase and particulate emissions. Standard petroleum JP-8 fuel, pure synthetic fuels produced from natural gas and coal feedstocks using the Fischer-Tropsch (FT) process, and 50% blends of both fuels were tested in the CFM-56 engines on a DC-8 aircraft. To examine plume chemistry and particle evolution with time, samples were drawn from inlet probes positioned 1, 30, and 145 m downstream of the aircraft engines. No significant alteration to engine performance was measured when burning the alternative fuels. However, leaks in the aircraft fuel system were detected when operated with the pure FT fuels as a result of the absence of aromatic compounds in the fuel. Dramatic reductions in soot emissions were measured for both the pure FT fuels (reductions of 84% averaged over all powers) and blended fuels (64%) relative to the JP-8 baseline with the largest reductions at idle conditions. The alternative fuels also produced smaller soot (e.g. at 85% power, volume mean diameters were reduced from 78 nm for JP-8 to 51 nm for the FT fuel), which may reduce their ability to act as cloud condensation nuclei (CCN). The reductions in particulate emissions are expected for all alternative fuels with similar reductions in fuel sulfur and aromatic content regardless of the feedstock. As the plume cools downwind of the engine, nucleation-mode aerosols form. For the pure FT fuels, reductions (94% averaged over all powers) in downwind particle number emissions were similar to those measured at the exhaust plane (84

  8. Wabash Valley Integrated Gasification Combined Cycle, Coal to Fischer Tropsch Jet Fuel Conversion Study

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Jayesh [Lummus Technology Inc., Bloomfield, NJ (United States); Hess, Fernando [Lummus Technology Inc., Bloomfield, NJ (United States); Horzen, Wessel van [Lummus Technology Inc., Bloomfield, NJ (United States); Williams, Daniel [Lummus Technology Inc., Bloomfield, NJ (United States); Peevor, Andy [JM Davy, London (United Kingdom); Dyer, Andy [JM Davy, London (United Kingdom); Frankel, Louis [Canonsburgh, PA (United States)

    2016-06-01

    This reports examines the feasibility of converting the existing Wabash Integrated Gasification Combined Cycle (IGCC) plant into a liquid fuel facility, with the goal of maximizing jet fuel production. The fuels produced are required to be in compliance with Section 526 of the Energy Independence and Security Act of 2007 (EISA 2007 §526) lifecycle greenhouse gas (GHG) emissions requirements, so lifecycle GHG emissions from the fuel must be equal to or better than conventional fuels. Retrofitting an existing gasification facility reduces the technical risk and capital costs associated with a coal to liquids project, leading to a higher probability of implementation and more competitive liquid fuel prices. The existing combustion turbine will continue to operate on low cost natural gas and low carbon fuel gas from the gasification facility. The gasification technology utilized at Wabash is the E-Gas™ Technology and has been in commercial operation since 1995. In order to minimize capital costs, the study maximizes reuse of existing equipment with minimal modifications. Plant data and process models were used to develop process data for downstream units. Process modeling was utilized for the syngas conditioning, acid gas removal, CO2 compression and utility units. Syngas conversion to Fischer Tropsch (FT) liquids and upgrading of the liquids was modeled and designed by Johnson Matthey Davy Technologies (JM Davy). In order to maintain the GHG emission profile below that of conventional fuels, the CO2 from the process must be captured and exported for sequestration or enhanced oil recovery. In addition the power utilized for the plant’s auxiliary loads had to be supplied by a low carbon fuel source. Since the process produces a fuel gas with sufficient energy content to power the plant’s loads, this fuel gas was converted to hydrogen and exported to the existing gas turbine for low carbon power production. Utilizing low carbon fuel gas and

  9. Ultra-clean Fischer-Tropsch (F-T) Fuels Production and Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    Stephen P. Bergin

    2006-06-30

    The objective of the DOE-NETL Fischer-Tropsch (F-T) Production and Demonstration Program was to produce and evaluate F-T fuel derived from domestic natural gas. The project had two primary phases: (1) fuel production of ultra-clean diesel transportation fuels from domestic fossil resources; and (2) demonstration and performance testing of these fuels in engines. The project also included a well-to-wheels economic analysis and a feasibility study of small-footprint F-T plants (SFPs) for remote locations such as rural Alaska. During the fuel production phase, ICRC partnered and cost-shared with Syntroleum Corporation to complete the mechanical design, construction, and operation of a modular SFP that converts natural gas, via F-T and hydro-processing reactions, into hydrogensaturated diesel fuel. Construction of the Tulsa, Oklahoma plant started in August 2002 and culminated in the production of over 100,000 gallons of F-T diesel fuel (S-2) through 2004, specifically for this project. That fuel formed the basis of extensive demonstrations and evaluations that followed. The ultra-clean F-T fuels produced had virtually no sulfur (less than 1 ppm) and were of the highest quality in terms of ignition quality, saturation content, backend volatility, etc. Lubricity concerns were investigated to verify that commercially available lubricity additive treatment would be adequate to protect fuel injection system components. In the fuel demonstration and testing phase, two separate bus fleets were utilized. The Washington DC Metropolitan Area Transit Authority (WMATA) and Denali National Park bus fleets were used because they represented nearly opposite ends of several spectra, including: climate, topography, engine load factor, mean distance between stops, and composition of normally used conventional diesel fuel. Fuel evaluations in addition to bus fleet demonstrations included: bus fleet emission measurements; F-T fuel cold weather performance; controlled engine dynamometer

  10. Organizational memory: from expectations memory to procedural memory

    NARCIS (Netherlands)

    Ebbers, J.J.; Wijnberg, N.M.

    2009-01-01

    Organizational memory is not just the stock of knowledge about how to do things, but also of expectations of organizational members vis-à-vis each other and the organization as a whole. The central argument of this paper is that this second type of organizational memory -organizational expectations

  11. Organizational memory: from expectations memory to procedural memory

    NARCIS (Netherlands)

    Ebbers, J.J.; Wijnberg, N.M.

    2009-01-01

    Organizational memory is not just the stock of knowledge about how to do things, but also of expectations of organizational members vis-à-vis each other and the organization as a whole. The central argument of this paper is that this second type of organizational memory -organizational expectations

  12. Modulatory mechanisms of cortisol effects on emotional learning and memory: Novel perspectives

    OpenAIRE

    Vanessa A. van Ast; Cornelisse, Sandra; Marin, Marie-France; Ackermann, Sandra; Garfinkel, Sara; Abercrombie, Heather C.

    2013-01-01

    It has long been known that cortisol affects learning and memory processes. Despite a wealth of research dedicated to cortisol effects on learning and memory, the strength or even directionality of the effects often vary. A number of the factors that alter cortisol’s effects on learning and memory are well-known. For instance, effects of cortisol can be modulated by emotional arousal and the memory phase under study. Despite great advances in understanding factors that explain variability in ...

  13. Exploring history and memory through autobiographical memory

    Directory of Open Access Journals (Sweden)

    Ivor Goodson

    2015-02-01

    Full Text Available The article reviews the role of autobiographical memory as a site of narrative construction. Far from being a place of liberal retrospective recall it is a site of active recapitulation and reconstruction. The article provides examples of how history and memory are intermingled. It also draws in the author’s autobiographical vignettes to explore the underpinning desires for historical reconstruction in autobiographical memory work

  14. 5-HT6 receptor memory and amnesia: behavioral pharmacology--learning and memory processes.

    Science.gov (United States)

    Meneses, Alfredo; Pérez-García, Georgina; Ponce-Lopez, Teresa; Castillo, Carlos

    2011-01-01

    Growing evidence indicates that antagonists of the 5-hydroxytryptamine (serotonin) receptor6 (5-HT6) improve memory and reverse amnesia, although the mechanisms involved are poorly understood. Hence, in this paper an attempt was made to summarize recent findings. Available evidence indicates that diverse 5-HT6 receptor antagonists produce promnesic and/or antiamnesic effects in diverse conditions, including memory formation, age-related cognitive impairments, memory deficits in diseases such as schizophrenia, Parkinson, and Alzheimer's disease (AD). Notably, some 5-HT6 receptor agonists seem to have promnesic and/or antiamnesic effects. At the present, it is unclear why 5-HT6 receptor agonists and antagonists may facilitate memory or may reverse amnesia in some memory tasks. Certainly, 5-HT6 drugs modulate memory, which are accompanied with neural changes. Likewise, memory, aging, and AD modify 5-HT6 receptors and signaling cascades. Further investigation in different memory tasks, times, and amnesia models together with more complex control groups might provide further clues. Notably, human studies suggest a potential utility of 5-HT6 receptor antagonists in mild-to-moderate AD patients. Even individuals with mild cognitive impairment (MCI) offer a great opportunity to test them.

  15. Memory Without Parties or Parties Without Memory?

    Directory of Open Access Journals (Sweden)

    Juan Mario Solís Delgadillo

    2011-01-01

    Full Text Available This paper explores the role of political parties in Argentina, Chile and Guatemala in relation to the implementation of public policies of memory after the return to democracy in each of these countries. To do this, we discuss the concept of memory and the problems of memorial obsession. We consider the uses and abuses of memory that human rights organizations manifest on the subject, and examine the work of the parties about the level of adaptation that allows claims of human rights movement to become matters of public policy.

  16. Effect of operating conditions and potassium content on Fischer-Tropsch liquid products produced by potassium-promoted iron catalysts

    Institute of Scientific and Technical Information of China (English)

    Francisco E. M. Farias; Fernando G. Sales; Fabiano A. N. Fernandes

    2008-01-01

    The dependencies of Fischer-Tropsch synthesis liquid hydrocarbon product distribution on operating pressure and temperature have been studied over three potassium-promoted iron catalysts with increasing potassium molar content. The study followed an experimental planning and the results were analyzed based on surface response methodology. The effects of different operating conditions and potassium contents on the liquid product distribution were compared based on number average carbon number and dispersion. Results showed that high pressures (25 to 30 atm) favored the production of waxes that could be converted into liquid fuels through hydrocracking, while greater direct selectivity towards diesel was favored by low pressure (20 atm) using catalysts with low potassium to iron molar ratios. The liquid product distribution produced using an iron catalyst with high potassium content presented higher number-average number of carbons when compared to the distribution obtained using an iron catalyst with low potassium content.

  17. Record of Borearctia menetriesii (Eversmann, 1846 (Lepidoptera, Erebidae, Arctiinae larva on Aconitum rubicundum Fischer (Ranunculaceae in Eastern Siberia

    Directory of Open Access Journals (Sweden)

    Oleg E. Berlov

    2015-01-01

    Full Text Available In this note we report the first record of Borearctia menetriesii (Eversmann, 1846 (Erebidae: Arctiinae larva on a native host plant, Aconitum rubicundum Fischer (Ranunculaceae. This aconite species is a close relative of A. lycoctonum, which is widespread across Eurasia, but has a scattered distribution in Fennoscandia. The majority of B. menetriesii localities are situated within the distribution range of A. lycoctonum and other aconite taxa, which are diverse and widespread in the Eastern Palaearctic. However, only two of the six westernmost B. menetriesii localities in Finland are in accordance with sporadic records of A. lycoctonum. Our record confirms that B. menetriesii is a polyphagous species like most other boreal Arctiinae. We have expanded the list of a few Lepidoptera species which can use Aconitum spp. as suitable host plants despite the fact that they are poisonous for insects because of high alkaloid content.

  18. Synthesis of adenine, guanine, cytosine, and other nitrogen organic compounds by a Fischer-Tropsch-like process.

    Science.gov (United States)

    Yang, C. C.; Oro, J.

    1971-01-01

    Study of the formation of purines, pyrimidines, and other bases from CO, H2, and NH3 under conditions similar to those used in the Fischer-Tropsch process. It is found that industrial nickel/iron alloy catalyzes the synthesis of adenine, guanine, cytosine, and other nitrogenous compounds from mixtures of CO, H2, and NH3 at temperatures of about 600 C. Sufficient sample was accumulated to isolate as solid products adenine, guanine, and cytosine, which were identified by infrared spectrophotometry. In the absence of nickel/iron catalyst, at 650 C, or in the presence of this catalyst, at 450 C, no purines or pyrimidines were synthesized. These results confirm and extend some of the work reported by Kayatsu et al. (1968).

  19. Thermal decomposition and cobalt species transformation of carbon nanotubes supported cobalt catalyst for Fischer-Tropsch synthesis

    Institute of Scientific and Technical Information of China (English)

    Jing Lü; Chengdu Huang; Suli Bai; Yunhui Jiang; Zhenhua Li

    2012-01-01

    The effect of calcination condition on the cobalt species and Fischer-Tropsch synthesis (FTS) was studied.It was found that higher calcination temperature resulted in decreased FTS activities because CNTs were consumed by oxidation in air at temperature higher than 230 ℃.Cobalt species went through transformation from Co3O4 to metallic Co in Ar by autoreduction at temperature over 500 ℃.The autoreduction route might be Co3O4→CoO→Co or Co3O4→Co2C→Co.Reduction at temperature higher than 500 ℃ also resulted in decreased FTS activities due to the methanation of CNTs in hydrogen.

  20. Toxicity of Bacillus thuringiensis (L.) Cry proteins against summer fruit tortrix (Adoxophyes orana - Fischer von Rösslerstamm).

    Science.gov (United States)

    Radosavljevic, Jelena; Naimov, Samir

    2016-07-01

    The activity of seven Cry1, one Cry9 and one hybrid Cry1 protoxins against neonate larvae of summer fruit tortrix (Adoxophyes orana - Fischer von Rösslerstamm) has been investigated. Cry1Ia is identified as the most toxic protein, followed by Cry1Aa and Cry1Ac. Cry1Ca, Cry1Cb, Cry1Da and Cry1Fa were less active, while SN19 (Cry1 hybrid protein with domain composition 1Ba/1Ia/1Ba) and Cry9Aa exhibited negligible toxicity against A. orana. In vitro trypsin-activated Cry1Ac is still less active than Cry1Ia protoxin, suggesting that toxicity of Cry1Ia is most probably due to more complex differences in further downstream processing, toxin-receptor interactions and pore formation in A. orana's midgut epithelium.

  1. Fischer-Tropsch synthesis over ruthenium-promoted Co/Al2O3 catalyst with different reduction procedures

    Institute of Scientific and Technical Information of China (English)

    Ali Karimi; Ali Nakhaei Pour; Farshad Torabi; Behnam Hatami; Ahmad Tavasoli; Mohammad Reza Alaei; Mohammad Irani

    2010-01-01

    The effect of reduction procedure on catalyst properties,activity and products selectivity of ruthenium-promoted Co/γ-Al2O3 catalyst in Fischer-Tropsch synthesis(FTS)was investigated.Catalyst samples were reduced with different reduction gas compositions and passivated before being characterized by TPR and XRD techniques.Different activity and product selectivity analyses were also performed.These results showed that the catalyst dispersion,particle size,and the degree of reduction changed with different reduction gas compositions,which were resulted from the water partial pressures in reduction process that give varying degrees of interaction with the support.It has been suggested that the FTS activity of cobalt catalyst was directly dependent on the catalyst reducibility.A reduction gas with a molar ratio of H2/He = 1 was used to prevent the formation of Co-support compound during catalyst reduction.

  2. Differentiation of rye and wheat flour as well as mixtures by using the kinetics of Karl Fischer water titration.

    Science.gov (United States)

    Hădărugă, Daniel I; Costescu, Corina I; Corpaş, Laura; Hădărugă, Nicoleta G; Isengard, Heinz-Dieter

    2016-03-15

    The aim of this study was to find a simple way to differentiate between rye and wheat flour and their mixtures by using the kinetic parameters of Karl Fischer water titration (KFT). Consequently, the water content and type of molecules in rye and wheat mixtures used in Romanian bread making have been investigated by means of volumetric KFT. Further, the kinetics of KFT have been determined and novel kinetic parameters corresponding to "surface" and "strongly-retained" water molecules have been identified to discriminate between rye and wheat flour and their mixtures. The "surface" and "strongly-retained" water reaction rates well correlate with the rye content in the flour mixtures, especially at higher temperature analysis (r>0.95). These parameters can be used as indicators for quality evaluation of such type of mixtures, as well as to identify adulteration by improper use of the rye-wheat flour ratios in bread making.

  3. TPR and TPD studies of effects of Cu and Ca promotion on Fe-Zn-based Fischer-Tropsch catalysts

    Indian Academy of Sciences (India)

    Olusola O James; Biswajit Chowdhury; Sudip Maity

    2013-05-01

    Temperature-programmed reduction (TPR) and temperature-programmed desorption (TPD) were used to study the effects of Cu and Ca promotion on Fe-Zn-based Fischer-Tropsch catalysts. The reduction temperature for Fe2O3 → Fe3O4 was unaffected by Ca addition but decreased when promoted with Cu. Fe-Zn promoted with Cu and Ca showed even much lower reduction temperature for Fe2O3→Fe3O4. Ca promotion enhances carburization and increases surface acidity and basicity of the Fe-Zn oxide precursor. While Cu inhibits carburization and decreases the surface acidity and basicity of the Fe-Zn oxide precursor. The implications of these effects on the application of catalysts for FT are discussed.

  4. Effect of Surface Modification by Chelating Agents on Fischer- Tropsch Performance of Co/SiO{sub 2} Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Bambal, Ashish S.; Kugler, Edwin L.; Gardner, Todd H.; Dadyburjor, Dady B.

    2013-11-14

    The silica support of a Co-based catalyst for Fischer-Tropsch (FT) synthesis was modified by the chelating agents (CAs) nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid (EDTA). After the modification, characterization of the fresh and spent catalysts show reduced crystallite sizes, a better-dispersed Co₃O₄ phase on the calcined samples, and increased metal dispersions for the reduced samples. The CA-modified catalysts display higher CO conversions, product yields, reaction rates and rate constants. The improved FT performance of CA-modified catalysts is attributed to the formation of stable complexes with Co. The superior performance of the EDTA-modified catalyst in comparison to the NTA-modified catalyst is due to the higher affinity of the former for complex formation with Co ions.

  5. [I don't want to be eternally imprisoned in the cage of my own self . . .". assumptions about the relationship between Sigmund Freud and his juvenile patient Arthur Fischer-Colbrie (1895-1968)].

    Science.gov (United States)

    Walder, Christine

    2010-01-01

    The Austrian writer A. Fischer-Colbrie underwent an analysis with Freud in 1915-16 and then again in 1919. Based on his literary estate, this article tries to shed some light on the biographical background and the precipitating factors of his mental problems. When the cure had to be interrupted because of the young man's military service, Freud sustained an unusual correspondence with him that reflected his efforts to maintain their therapeutic contact. At the same time his letters witness Fischer-Colbrie's burgeoning literary talents.--An appendix presents Freud's letters to Fischer-Colbrie, edited and annotated by Michael Schröter.

  6. Ototoxicity of 12 mg/kg cisplatin in the Fischer 344/NHsd rat using multiple dosing strategies.

    Science.gov (United States)

    Harrison, Ryan T; Seiler, Brittany M; Bielefeld, Eric C

    2016-09-01

    Ototoxicity continues to be a major dose-limiting side effect of cis-diamminedichloroplatinum(II) (cisplatin). With an ongoing need to develop pharmaceutical protection strategies for cisplatin's ototoxicity, there is also a need to develop stable in-vivo mammalian models of cisplatin ototoxicity. The current study examined the difference in ototoxicity of a cumulative 12 mg/kg dose of cisplatin in the Fischer 344/NHsd rat when administered over four different dosing protocols. Hearing sensitivity was measured using free-field auditory brainstem response thresholds under anesthesia. Rats were divided into four groups. The first group was administered 12 mg/kg of cisplatin in a single bolus infusion. The second group was administered two 6 mg/kg infusions separated by 7 days. The third group was administered 3 mg/kg injections once per day for 4 consecutive days. The fourth group was administered 3 mg/kg injections in four injections separated by 3 days each. Hearing thresholds and body weights were measured at 3 and 7 days after the final cisplatin exposure. Postmortem sensory cell counts were used to confirm injury to the auditory system. The 4 consecutive days of 3 mg/kg induced a greater mortality rate and greater hearing loss at day 3 than the other experimental protocols. The 3 mg/kg administered every 3 days induced less sensory cell loss than the other conditions. The findings indicate that 4 consecutive days of 3 mg/kg cisplatin is not a viable ototoxicity model in the Fischer 344/NHsd rat, but that the other models are all effective in inducing comparable cochlear injuries.

  7. Fischer-344 Tp53-knockout rats exhibit a high rate of bone and brain neoplasia with frequent metastasis.

    Science.gov (United States)

    Hansen, Sarah A; Hart, Marcia L; Busi, Susheel; Parker, Taybor; Goerndt, Angela; Jones, Kevin; Amos-Landgraf, James M; Bryda, Elizabeth C

    2016-10-01

    Somatic mutations in the Tp53 tumor suppressor gene are the most commonly seen genetic alterations in cancer, and germline mutations in Tp53 predispose individuals to a variety of early-onset cancers. Development of appropriate translational animal models that carry mutations in Tp53 and recapitulate human disease are important for drug discovery, biomarker development and disease modeling. Current Tp53 mouse and rat models have significant phenotypic and genetic limitations, and often do not recapitulate certain aspects of human disease. We used a marker-assisted speed congenic approach to transfer a well-characterized Tp53-mutant allele from an outbred rat to the genetically inbred Fischer-344 (F344) rat to create the F344-Tp53(tm1(EGFP-Pac)Qly)/Rrrc (F344-Tp53) strain. On the F344 genetic background, the tumor spectrum shifted, with the primary tumor types being osteosarcomas and meningeal sarcomas, compared to the hepatic hemangiosarcoma and lymphoma identified in the original outbred stock model. The Fischer model is more consistent with the early onset of bone and central nervous system sarcomas found in humans with germline Tp53 mutations. The frequency of osteosarcomas in F344-Tp53 homozygous and heterozygous animals was 57% and 36%, respectively. Tumors were highly representative of human disease radiographically and histologically, with tumors found primarily on long bones with frequent pulmonary metastases. Importantly, the rapid onset of osteosarcomas in this promising new model fills a current void in animal models that recapitulate human pediatric osteosarcomas and could facilitate studies to identify therapeutic targets.

  8. Fischer-344 Tp53-knockout rats exhibit a high rate of bone and brain neoplasia with frequent metastasis

    Directory of Open Access Journals (Sweden)

    Sarah A. Hansen

    2016-10-01

    Full Text Available Somatic mutations in the Tp53 tumor suppressor gene are the most commonly seen genetic alterations in cancer, and germline mutations in Tp53 predispose individuals to a variety of early-onset cancers. Development of appropriate translational animal models that carry mutations in Tp53 and recapitulate human disease are important for drug discovery, biomarker development and disease modeling. Current Tp53 mouse and rat models have significant phenotypic and genetic limitations, and often do not recapitulate certain aspects of human disease. We used a marker-assisted speed congenic approach to transfer a well-characterized Tp53-mutant allele from an outbred rat to the genetically inbred Fischer-344 (F344 rat to create the F344-Tp53tm1(EGFP-PacQly/Rrrc (F344-Tp53 strain. On the F344 genetic background, the tumor spectrum shifted, with the primary tumor types being osteosarcomas and meningeal sarcomas, compared to the hepatic hemangiosarcoma and lymphoma identified in the original outbred stock model. The Fischer model is more consistent with the early onset of bone and central nervous system sarcomas found in humans with germline Tp53 mutations. The frequency of osteosarcomas in F344-Tp53 homozygous and heterozygous animals was 57% and 36%, respectively. Tumors were highly representative of human disease radiographically and histologically, with tumors found primarily on long bones with frequent pulmonary metastases. Importantly, the rapid onset of osteosarcomas in this promising new model fills a current void in animal models that recapitulate human pediatric osteosarcomas and could facilitate studies to identify therapeutic targets.

  9. Fitzgerald and The Great Gatsby

    Institute of Scientific and Technical Information of China (English)

    王利娟

    2014-01-01

    F. Scott Fitzgerald, the famous American novelist in the 1920s, is famous as the spokesman and laureate of the“The Lost Generation”. Considered one of Fitzgerald’s representative works and the finest achievement of his literary career, The Great Gatsby is widely recognized as a classic of American literature. Since its publication in 1925, it has been a continual hot sub⁃ject of critical attention,and studies on it have never stopped. This paper provides a detailed account of“the Fitzgerald revival”as well as the previous criticism on The Great Gatsby.

  10. Famous puzzles of great mathematicians

    CERN Document Server

    Petković, Miodrag S

    2009-01-01

    This entertaining book presents a collection of 180 famous mathematical puzzles and intriguing elementary problems that great mathematicians have posed, discussed, and/or solved. The selected problems do not require advanced mathematics, making this book accessible to a variety of readers. Mathematical recreations offer a rich playground for both amateur and professional mathematicians. Believing that creative stimuli and aesthetic considerations are closely related, great mathematicians from ancient times to the present have always taken an interest in puzzles and diversions. The goal of this

  11. Medications for Memory Loss

    Science.gov (United States)

    ... by state Home > Alzheimer's Disease > Treatments > Medications for Memory Overview What Is Dementia? What Is Alzheimer's? Younger/ ... Interactive Tour Risk Factors Diagnosis Treatments Medications for Memory Treatments for Behavior For Sleep Changes Alternative Treatments ...

  12. Tracing Cultural Memory

    DEFF Research Database (Denmark)

    Wiegand, Frauke Katharina

    We encounter, relate to and make use of our past and that of others in multifarious and increasingly mobile ways. Tourism is one of the main paths for encountering sites of memory. This thesis examines tourists’ creative appropriations of sites of memory – the objects and future memories inspired...... by their encounters – to address a question that thirty years of ground - breaking research into memory has not yet sufficiently answered: What can we learn about the dynamics of cultural memory by examining mundane accounts of touristic encounters with sites of memory? From Blaavand Beach in Western Denmark...... to Soweto’s Regina Mundi Church, this thesis analyses tourists’ snapshots at sites of memory and outlines their tracing activity in cultural memory. It draws on central concepts of actor - network theory and visual culture studies for a cross - disciplinary methodology to comprehend the collective...

  13. Coping with Memory Loss

    Science.gov (United States)

    ... Consumers Home For Consumers Consumer Updates Coping With Memory Loss Share Tweet Linkedin Pin it More sharing ... a health professional. back to top What Causes Memory Loss? Anything that affects cognition—the process of ...

  14. Music, memory and emotion

    National Research Council Canada - National Science Library

    Jäncke, Lutz

    2008-01-01

    Because emotions enhance memory processes and music evokes strong emotions, music could be involved in forming memories, either about pieces of music or about episodes and information associated with particular music...

  15. Memory and Aging

    Science.gov (United States)

    Memory and Aging Losing keys, misplacing a wallet, or forgetting someone’s name are common experiences. But for people nearing or over age 65, such memory lapses can be frightening. They wonder if they ...

  16. The Great Principles of Computing

    OpenAIRE

    2010-01-01

    The article of record as published may be found at http://dx.doi.org/The article of record as published may be found at http://dx.doi.org/10.1145/948383.948400 American Scientist,. Computing may be the fourth great domain of science, along with the physical, life, and social sciences.

  17. The Great Gatsby. [Lesson Plan].

    Science.gov (United States)

    Zelasko, Ken

    Based on F. Scott Fitzgerald's novel "The Great Gatsby," this lesson plan presents activities designed to help students understand that adapting part of a novel into a dramatic reading makes students more intimate with the author's intentions and craft; and that a part of a novel may lend itself to various oral interpretations. The main activity…

  18. Myths of the Great War

    OpenAIRE

    Harrison, Mark

    2014-01-01

    We review some "myths" of the Great War of 1914 to 1918: that the war broke out inadvertently, that the western front saw needless slaughter, that the Allies used the food weapon to strangle Germany, and that the peace treaty that ended the war caused the rise of Hitler and the still greater war that followed.\\ud

  19. Great Lakes' regional climate regimes

    Science.gov (United States)

    Kravtsov, Sergey; Sugiyama, Noriyuki; Roebber, Paul

    2016-04-01

    We simulate the seasonal cycle of the Great Lakes' water temperature and lake ice using an idealized coupled lake-atmosphere-ice model. Under identical seasonally varying boundary conditions, this model exhibits more than one seasonally varying equilibrium solutions, which we associate with distinct regional climate regimes. Colder/warmer regimes are characterized by abundant/scarce amounts of wintertime ice and cooler/warmer summer temperatures, respectively. These regimes are also evident in the observations of the Great Lakes' climate variability over recent few decades, and are found to be most pronounced for Lake Superior, the deepest of the Great Lakes, consistent with model predictions. Multiple climate regimes of the Great Lakes also play a crucial role in the accelerated warming of the lakes relative to the surrounding land regions in response to larger-scale global warming. We discuss the physical origin and characteristics of multiple climate regimes over the lakes, as well as their implications for a longer-term regional climate variability.

  20. The Great Bug Hunt 2011

    Science.gov (United States)

    Dixon-Watmough, Rebecca

    2011-01-01

    The Association For Science Education's "schoolscience.co.uk Great Bug Hunt 2011," in association with Martin Rapley and Gatekeeper Educational, has been a resounding success--not only because it fits into the science curriculum so neatly, but also because of the passion it evoked in the children who took part. This year's entries were…

  1. The Great Goddesses of Egypt

    Institute of Scientific and Technical Information of China (English)

    SheldonGosline; KatjaReinhardt; NortheastNormalUniversity

    2000-01-01

    Norman,Oklahoma:UniversityofOklahomaPress:Norman,1999.ISBN0-8061-3202-7.Pp.319.US$19.95.TheGreatGoddessesofEgyptstelltsiebenGoettinnenindenMittelpunktderagyptischenReligionsgeschichte:Nut,Neith,Nechbet,Wadjet,Hathor,MutundIsis.JederGottinisteineigenesKapitelgewidmet,zusatzlichsindeineEinfuhrung,diesichkurzmitderFnihdynastischenZeitbeschaftigt,undeinKapitelzuTempelundKultbeigefugt.EinGlossar,dasGottinnen(keineGotter)undeinigeimTexterwahnteKoniginnenauffuhrt,undeineausfuhrlicheBibliographieschlierendasBuchab....

  2. Symbols in the Great Gatsby

    Institute of Scientific and Technical Information of China (English)

    徐琰

    2016-01-01

    This paper analyzes the symbols in the book"The Great Gatsby" which include some particular places, objects, characters, settings and actions. These symbols are considered to have values different from what they are symbolized and most of them are connected to the theme of the novel-the corruption of the American dream.

  3. The Great War. [Teaching Materials].

    Science.gov (United States)

    Public Broadcasting Service, Washington, DC.

    This package of teaching materials is intended to accompany an eight-part film series entitled "The Great War" (i.e., World War I), produced for public television. The package consists of a "teacher's guide,""video segment index,""student resource" materials, and approximately 40 large photographs. The video series is not a war story of battles,…

  4. Great Expectations and New Beginnings

    Science.gov (United States)

    Davis, Frances A.

    2009-01-01

    Great Expectation and New Beginnings is a prenatal family support program run by the Family, Infant, and Preschool Program (FIPP) in North Carolina. FIPP has developed an evidence-based integrated framework of early childhood intervention and family support that includes three primary components: providing intervention in everyday family…

  5. Experimental Studies and Modeling of Synthesis Gas Production and Fischer-Tropsch Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Rafiq, Muhammad Hamid

    2012-07-01

    In this work, an investigation on the production of synthetic fuel from gaseous hydrocarbons (HCs)/bio-HCs and liquid bio-HCs on a small-scale unit has been carried out. The research project consists of two major parts, a modified version of a plasma-assisted catalytic partial oxidation (CPO) gliding arc (GlidArc) reactor and a thermally stable single-tube fixed-bed Fischer-Tropsch (FT) reactor. The potential for the CPO of methane to produce synthesis gas (syngas) was studied experimentally and thermodynamically at a fixed pressure (1 bar) and electric power (0.3 kw). The investigations were performed in a partially adiabatic plasma-assisted (nonthermal) GlidArc reactor, using a Ni-based catalyst. Two cases were studied: in the first, normal air (molar ratio of O2/N2=21/79) was used, whereas enriched air (O2/N2=40/60) was utilized in the second. The individual effect of the O2/CH4 molar ratio, gas hour space velocity (GHSV) and bed exiting temperature (Texit) was studied for both cases. The main trends of the CH4 conversion, the syngas (H2 and CO) yield and the thermal efficiency of the reactor based on the lower heating value (LHV) were analyzed and compared. A numerical investigation of the CPO of methane to syngas using a GlidArc reactor was also studied. A 2D heterogeneous plug-flow model with radial dispersion and no gradients inside the catalyst pellet are used, including the transport equations for the gas and solid phase and reaction rate equations. The governing equations of this model formed a set of stationary differential algebraic equations coupled with the non-linear algebraic equations, and were solved numerically using in-house MATLAB code. Model results of CPO of methane were compared to previous experimental data with the GlidArc reactor found in the literature. A close match between the calculated and experimental results for temperature, reactant (CH4 and O2) conversion, H2 and CO yields and species molefraction were obtained. The developed

  6. Model studies of secondary hydrogenation in Fischer-Tropsch synthesis studied by cobalt catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Aaserud, Christian

    2003-07-01

    Mass transfer effects are very important in Fischer-Tropsch (FT) synthesis. In order to study the FT synthesis without the influence of any transport limitations, cobalt foils have been used as model catalysts. The effect of pretreatment (number of calcinations and different reduction times) for cobalt foil catalysts at 220 {sup o}C, 1 bar and H{sub 2}/CO = 3 has been studied in a microreactor. The foils were examined by Scanning electron microscopy (SEM). It was found that the catalytic activity of the cobalt foil increases with the number of pretreatments possibly due to an increase in the surface area of the cobalt foil. The SEM results support the assumption that the surface area of the cobalt foil increases with the number of pretreatments. The reduction time was also found to influence the catalytic activity of the cobalt foil. Highest activity was obtained using a reduction time of only five min (compared to one and thirty min). The decrease in activity after reduction for thirty min compared to five min was suggested to be due to restructuring of the surface of the cobalt foil and a reduction time of only 1 min was not enough to reduce the cobalt foil sufficiently. Time of reduction did also influence the product distribution. Increased reduction time resulted in a lower selectivity to light products and increased selectivity to heavier components. The paraffin/olefin ratio increased with increasing CO-conversion also for cobalt foils. The paraffin/olefin ratio also increased when the reduction period of the cobalt foil was increased at a given CO-conversion. Hydrogenation of propene to propane has been studied as a model reaction for secondary hydrogenation of olefins in the FT synthesis. The study has involved promoted and unpromoted cobalt FT catalysts supported on different types of supports and also unsupported cobalt. Hydrogenation of propene was carried out at 120 {sup o}C, 1.8 bar and H{sub 2}/C{sub 3}H{sub 6} 6 in a fixed bed microreactor. The rate

  7. Competition between copper and silver in Fischer rats with a normal copper metabolism and in Long-Evans Cinnamon rats with an abnormal copper metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Sugawara, N.; Sugawara, C. [Sapporo Medical Univ. (Japan). Dept. of Public Health

    2000-07-01

    Long-Evans Cinnamon (LEC) rats inherently lacking in serum ceruloplasmin (CP) activity and biliary Cu excretion were established from a closed colony of Long-Evans rats. These deficiencies, linked to a dysfunction of P-type ATPase, stimulate deposition of Cu and then of Cu metallothionein (MT) in the liver. Male LEC and Fischer rats were injected subcutaneously with Ag (AgNO{sub 3}), which is an antagonist to Cu. They were operated on 24 h after the injection while under anesthesia. Total uptake of Ag into the liver was not stimulated, but its uptake into the MT fraction increased significantly in the LEC rats. Ag injection notably decreased the activity of serum CP in the Fischer rats, but not in the LEC rats. The decrease was accompanied by a reduction of serum Cu. In Fischer rat serum treated with Ag, Ag was detected mainly in the albumin region and partly in the CP fraction. In LEC rat serum, however, the Ag concentration was about 1/20 of that in the Fischer rats, and Ag was not detected in the CP fraction. Ag injection decreased the biliary excretion of Cu in the Fischer rats (0.183-0.052 {mu}g Cu/20 min sampling), but not in the LEC rats (0.014-0.014 {mu}g Cu/20 min sampling). On the other hand, biliary excretion of Ag was much greater in the Fischer rats (1.25 {mu}g Ag/20 min) than in the LEC rats (0.04 {mu}g Ag/20 min). Our results suggest that uptake of Ag into the liver is not dependent on the hepatic Cu content and status, but that biliary excretion of Ag from the liver is affected by these. Hepatic MT is not a transporter of hepatobiliary excretion of Cu and Ag. It seems likely that, unlike Cu excretion, Ag is excreted by not only the CP route but also by another route into the serum. Ag may compete with Cu in the uptake into CP (conversion of apo-CP to holo-CP). (orig.)

  8. Saving Malta's music memory

    OpenAIRE

    Sant, Toni

    2013-01-01

    Maltese music is being lost. Along with it Malta loses its culture, way of life, and memories. Dr Toni Sant is trying to change this trend through the Malta Music Memory Project (M3P) http://www.um.edu.mt/think/saving-maltas-music-memory-2/

  9. Music, memory and emotion.

    Science.gov (United States)

    Jäncke, Lutz

    2008-08-08

    Because emotions enhance memory processes and music evokes strong emotions, music could be involved in forming memories, either about pieces of music or about episodes and information associated with particular music. A recent study in BMC Neuroscience has given new insights into the role of emotion in musical memory.

  10. Combining individual memory & collective memory? : Classics Illustrated’s representation of World War II

    NARCIS (Netherlands)

    Ribbens, Kees

    WWII is widely remembered and represented. Keeping the memories of this international conflict alive, both within academic and popular history writing, occurred largely within various national frameworks. On the one hand, in the immediate post-war world many stories appeared about the great events

  11. Flexible Hybrid Organic-Inorganic Perovskite Memory.

    Science.gov (United States)

    Gu, Chungwan; Lee, Jang-Sik

    2016-05-24

    Active research has been done on hybrid organic-inorganic perovskite materials for application to solar cells with high power conversion efficiency. However, this material often shows hysteresis, which is undesirable, shift in the current-voltage curve. The hysteresis may come from formation of defects and their movement in perovskite materials. Here, we utilize the defects in perovskite materials to be used in memory operations. We demonstrate flexible nonvolatile memory devices based on hybrid organic-inorganic perovskite as the resistive switching layer on a plastic substrate. A uniform perovskite layer is formed on a transparent electrode-coated plastic substrate by solvent engineering. Flexible nonvolatile memory based on the perovskite layer shows reproducible and reliable memory characteristics in terms of program/erase operations, data retention, and endurance properties. The memory devices also show good mechanical flexibility. It is suggested that resistive switching is done by migration of vacancy defects and formation of conducting filaments under the electric field in the perovskite layer. It is believed that organic-inorganic perovskite materials have great potential to be used in high-performance, flexible memory devices.

  12. Two-dimensional shape memory graphene oxide

    Science.gov (United States)

    Chang, Zhenyue; Deng, Junkai; Chandrakumara, Ganaka G.; Yan, Wenyi; Liu, Jefferson Zhe

    2016-06-01

    Driven by the increasing demand for micro-/nano-technologies, stimuli-responsive shape memory materials at nanoscale have recently attracted great research interests. However, by reducing the size of conventional shape memory materials down to approximately nanometre range, the shape memory effect diminishes. Here, using density functional theory calculations, we report the discovery of a shape memory effect in a two-dimensional atomically thin graphene oxide crystal with ordered epoxy groups, namely C8O. A maximum recoverable strain of 14.5% is achieved as a result of reversible phase transition between two intrinsically stable phases. Our calculations conclude co-existence of the two stable phases in a coherent crystal lattice, giving rise to the possibility of constructing multiple temporary shapes in a single material, thus, enabling highly desirable programmability. With an atomic thickness, excellent shape memory mechanical properties and electric field stimulus, the discovery of a two-dimensional shape memory graphene oxide opens a path for the development of exceptional micro-/nano-electromechanical devices.

  13. Memory rehabilitation for the working memory of patients with multiple sclerosis (MS).

    Science.gov (United States)

    Mousavi, Shokoufeh; Zare, Hossein; Etemadifar, Masoud; Taher Neshatdoost, Hamid

    2017-07-24

    The main cognitive impairments in multiple sclerosis (MS) affect the working memory, processing speed, and performances that are in close interaction with one another. Cognitive problems in MS are influenced to a lesser degree by disease recovery medications or treatments,but cognitive rehabilitation is considered one of the promising methods for cure. There is evidence regarding the effectiveness of cognitive rehabilitation for MS patients in various stages of the disease. Since the impairment in working memory is one of the main MS deficits, a particular training that affects this cognitive domain can be of a great value. This study aims to determine the effectiveness of memory rehabilitation on the working memory performance of MS patients. Sixty MS patients with cognitive impairment and similar in terms of demographic characteristics, duration of disease, neurological problems, and mental health were randomly assigned to three groups: namely, experimental, placebo, and control. Patients' cognitive evaluation incorporated baseline assessments immediately post-intervention and 5 weeks post-intervention. The experimental group received a cognitive rehabilitation program in one-hour sessions on a weekly basis for 8 weeks. The placebo group received relaxation techniques on a weekly basis; the control group received no intervention. The results of this study showed that the cognitive rehabilitation program had a positive effect on the working memory performance of patients with MS in the experimental group. These results were achieved in immediate evaluation (post-test) and follow-up 5 weeks after intervention. There was no significant difference in working memory performance between the placebo group and the control group. According to the study, there is evidence for the effectiveness of a memory rehabilitation program for the working memory of patients with MS. Cognitive rehabilitation can improve working memory disorders and have a positive effect on the

  14. Memory: Organization and Control

    Science.gov (United States)

    Eichenbaum, Howard

    2017-01-01

    A major goal of memory research is to understand how cognitive processes in memory are supported at the level of brain systems and network representations. Especially promising in this direction are new findings in humans and animals that converge in indicating a key role for the hippocampus in the systematic organization of memories. New findings also indicate that the prefrontal cortex may play an equally important role in the active control of memory organization during both encoding and retrieval. Observations about the dialog between the hippocampus and prefrontal cortex provide new insights into the operation of the larger brain system that serves memory. PMID:27687117

  15. Recurrence Statistics of Great Earthquakes

    CERN Document Server

    Ben-Naim, E; Johnson, P A

    2013-01-01

    We investigate the sequence of great earthquakes over the past century. To examine whether the earthquake record includes temporal clustering, we identify aftershocks and remove those from the record. We focus on the recurrence time, defined as the time between two consecutive earthquakes. We study the variance in the recurrence time and the maximal recurrence time. Using these quantities, we compare the earthquake record with sequences of random events, generated by numerical simulations, while systematically varying the minimal earthquake magnitude Mmin. Our analysis shows that the earthquake record is consistent with a random process for magnitude thresholds 7.0<=Mmin<=8.3, where the number of events is larger. Interestingly, the earthquake record deviates from a random process at magnitude threshold 8.4<=Mmin<= 8.5, where the number of events is smaller; however, this deviation is not strong enough to conclude that great earthquakes are clustered. Overall, the findings are robust both qualitat...

  16. Ohlin on the Great Depression

    OpenAIRE

    Carlson, Benny; Jonung, Lars

    2013-01-01

    Bertil Ohlin was a most active commentator on current economic events in the interwar period, combining his academic work with a journalistic output of an impressive scale. He published more than a thousand newspaper articles in the 1920s and 1930s, more than any other professor in economics in Sweden. Here we have collected ten articles by Ohlin, translated from Swedish and originally published in Stockholms-Tidningen, to trace the evolution of his thinking during the Great Depression of the...

  17. Southern Great Plains Safety Orientation

    Energy Technology Data Exchange (ETDEWEB)

    Schatz, John

    2014-05-01

    Welcome to the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ARM) Southern Great Plains (SGP) site. This U.S. Department of Energy (DOE) site is managed by Argonne National Laboratory (ANL). It is very important that all visitors comply with all DOE and ANL safety requirements, as well as those of the Occupational Safety and Health Administration (OSHA), the National Fire Protection Association, and the U.S. Environmental Protection Agency, and with other requirements as applicable.

  18. Great Basin geoscience data base

    Science.gov (United States)

    Raines, Gary L.; Sawatzky, Don L.; Connors, Katherine A.

    1996-01-01

    This CD-ROM serves as the archive for 73 digital GIS data set for the Great Basin. The data sets cover Nevada, eastern California, southeastern Oregon, southern Idaho, and western Utah. Some of the data sets are incomplete for the total area. On the CD-ROM, the data are provided in three formats, a prototype Federal Data Exchange standard format, the ESRI PC ARCVIEW1 format for viewing the data, and the ESRI ARC/INFO export format. Extensive documentation is provided to describe the data, the sources, and data enhancements. The following data are provided. One group of coverages comes primarily from 1:2,000,000-scale National Atlas data and can be assembled for use as base maps. These various forms of topographic information. In addition, public land system data sets are provided from the 1:2,500,000-scale Geologic Map of the United States and 1:500,000-scale geologic maps of Nevada, Oregon, and Utah. Geochemical data from the National Uranium Resource Evaluation (NURE) program are provided for most of the Great Basin. Geophysical data are provided for most of the Great Basin, typically gridded data with a spacing of 1 km. The geophysical data sets include aeromagnetics, gravity, radiometric data, and several derivative products. The thematic data sets include geochronology, calderas, pluvial lakes, tectonic extension domains, distribution of pre-Cenozoic terranes, limonite anomalies, Landsat linear features, mineral sites, and Bureau of Land Management exploration and mining permits.

  19. Memory dynamics under stress.

    Science.gov (United States)

    Quaedflieg, Conny W E M; Schwabe, Lars

    2017-06-19

    Stressful events have a major impact on memory. They modulate memory formation in a time-dependent manner, closely linked to the temporal profile of action of major stress mediators, in particular catecholamines and glucocorticoids. Shortly after stressor onset, rapidly acting catecholamines and fast, non-genomic glucocorticoid actions direct cognitive resources to the processing and consolidation of the ongoing threat. In parallel, control of memory is biased towards rather rigid systems, promoting habitual forms of memory allowing efficient processing under stress, at the expense of "cognitive" systems supporting memory flexibility and specificity. In this review, we discuss the implications of this shift in the balance of multiple memory systems for the dynamics of the memory trace. Specifically, stress appears to hinder the incorporation of contextual details into the memory trace, to impede the integration of new information into existing knowledge structures, to impair the flexible generalisation across past experiences, and to hamper the modification of memories in light of new information. Delayed, genomic glucocorticoid actions might reverse the control of memory, thus restoring homeostasis and "cognitive" control of memory again.

  20. Immunological memory is associative

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.J.; Forrest, S. [New Mexico Univ., Albuquerque, NM (United States). Dept. of Computer Science; Perelson, A.S. [Los Alamos National Lab., NM (United States)

    1996-12-31

    The purpose of this paper is to show that immunological memory is an associative and robust memory that belongs to the class of sparse distributed memories. This class of memories derives its associative and robust nature by sparsely sampling the input space and distributing the data among many independent agents. Other members of this class include a model of the cerebellar cortex and Sparse Distributed Memory (SDM). First we present a simplified account of the immune response and immunological memory. Next we present SDM, and then we show the correlations between immunological memory and SDM. Finally, we show how associative recall in the immune response can be both beneficial and detrimental to the fitness of an individual.

  1. Flexible kernel memory.

    Science.gov (United States)

    Nowicki, Dimitri; Siegelmann, Hava

    2010-06-11

    This paper introduces a new model of associative memory, capable of both binary and continuous-valued inputs. Based on kernel theory, the memory model is on one hand a generalization of Radial Basis Function networks and, on the other, is in feature space, analogous to a Hopfield network. Attractors can be added, deleted, and updated on-line simply, without harming existing memories, and the number of attractors is independent of input dimension. Input vectors do not have to adhere to a fixed or bounded dimensionality; they can increase and decrease it without relearning previous memories. A memory consolidation process enables the network to generalize concepts and form clusters of input data, which outperforms many unsupervised clustering techniques; this process is demonstrated on handwritten digits from MNIST. Another process, reminiscent of memory reconsolidation is introduced, in which existing memories are refreshed and tuned with new inputs; this process is demonstrated on series of morphed faces.

  2. Flexible kernel memory.

    Directory of Open Access Journals (Sweden)

    Dimitri Nowicki

    Full Text Available This paper introduces a new model of associative memory, capable of both binary and continuous-valued inputs. Based on kernel theory, the memory model is on one hand a generalization of Radial Basis Function networks and, on the other, is in feature space, analogous to a Hopfield network. Attractors can be added, deleted, and updated on-line simply, without harming existing memories, and the number of attractors is independent of input dimension. Input vectors do not have to adhere to a fixed or bounded dimensionality; they can increase and decrease it without relearning previous memories. A memory consolidation process enables the network to generalize concepts and form clusters of input data, which outperforms many unsupervised clustering techniques; this process is demonstrated on handwritten digits from MNIST. Another process, reminiscent of memory reconsolidation is introduced, in which existing memories are refreshed and tuned with new inputs; this process is demonstrated on series of morphed faces.

  3. NAND flash memory technologies

    CERN Document Server

    Aritome, Seiichi

    2016-01-01

    This book discusses basic and advanced NAND flash memory technologies, including the principle of NAND flash, memory cell technologies, multi-bits cell technologies, scaling challenges of memory cell, reliability, and 3-dimensional cell as the future technology. Chapter 1 describes the background and early history of NAND flash. The basic device structures and operations are described in Chapter 2. Next, the author discusses the memory cell technologies focused on scaling in Chapter 3, and introduces the advanced operations for multi-level cells in Chapter 4. The physical limitations for scaling are examined in Chapter 5, and Chapter 6 describes the reliability of NAND flash memory. Chapter 7 examines 3-dimensional (3D) NAND flash memory cells and discusses the pros and cons in structure, process, operations, scalability, and performance. In Chapter 8, challenges of 3D NAND flash memory are dis ussed. Finally, in Chapter 9, the author summarizes and describes the prospect of technologies and market for the fu...

  4. Generating memory with vaccination.

    Science.gov (United States)

    Castellino, Flora; Galli, Grazia; Del Giudice, Giuseppe; Rappuoli, Rino

    2009-08-01

    The goal of vaccination is to induce long-lasting protective immune memory. Although most vaccines induce good memory responses, the type of memory induced by different vaccines may be considerably different. In addition, memory responses to the same vaccine may be influenced by age, environmental and genetic factors. Results emerging from detailed and integrated profiling of immune-responses to natural infection or vaccination suggest that the type and duration of immune memory are largely determined by the magnitude and complexity of innate immune signals that imprint the acquired immune primary responses. Here we summarize results obtained from analyzing human immune memory responses to different types of vaccines. We will also discuss how extending clinical investigation to events occurring early after vaccination can help identify early predictive markers of protective memory and thus contribute to faster development of better and safer vaccines.

  5. Ruthenium Modification on Mn and Zr-Modified Co/SiO2 Catalysts for Slurry-Phase Fischer-Tropsch Synthesis

    Directory of Open Access Journals (Sweden)

    Tomohisa Miyazawa

    2015-01-01

    Full Text Available The addition of Ru to Mn and Zr-modified Co/SiO2 catalysts, while applying different preparation orders and loading amounts, was investigated as a means of enhancing the Fischer-Tropsch synthesis reaction. The coimpregnation of Zr/SiO2 with Co, Mn and Ru gave the most attractive catalytic properties. This can be attributed to the higher dispersion of Co metal resulting from the coimpregnation of Co and Mn as well as enhanced reducibility due to the presence of Ru. The addition of a moderate amount of Ru together with the appropriate order of addition affected both the Co reducibility and the catalytic activity, primarily because of increased reducibility. The addition of even 0.1 wt.% Ru resulted in an obvious enhancement of Fischer-Tropsch synthesis activity.

  6. Slurry phase Fischer-Tropsch synthesis: Cobalt plus a water-gas shift catalyst. [Quarterly] report, October 1, 1989--December 31, 1989

    Energy Technology Data Exchange (ETDEWEB)

    Yates, I.C.; Satterfield, C.N.

    1989-12-31

    The rate of synthesis gas consumption over a cobalt FischerTropsch catalyst was measured in a well-mixed, continuous-flow, slurry reactor at 220 to 240{degrees}C, 0.5 to 1.5 MPa, H{sub 2}/CO feed ratios of 1.5 to 3.5 and conversions of 7 to 68% of hydrogen and 11 to 73% of carbon monoxide. The inhibiting effect of carbon monoxide was determined quantitatively and a Langmuir-Hinshelwood-type equation of the following form was found to best represent the results: -R{sub H{sub 2+Co}} = (a P{sub CO}P{sub H{sub 2}})/(1 + b P{sub CO}){sup 2}. The apparent activation energy was 93 to 95 kJ/mol. Data from previous studies on cobalt-based Fischer-Tropsch catalysts are also well correlated with this rate expression.

  7. ["Baur-Fischer-Lenz" in 1921-1940 critical book reviews: a quantitative study of contemporary reception of racial eugenics theories].

    Science.gov (United States)

    Fangerau, Heiner

    2003-01-01

    In 1921 the distinguished scientists Erwin Baur, Eugen Fischer and Fritz Lenz published the book "Menschliche Erblichkeitslehre und Rassenhygiene" in two volumes. Until 1941 their work went through 5 editions and became the standard textbook on human heredity and racial hygiene (eugenics) in Germany. Between 1921 and 1941 Baur's, Fischer's and Lenz's book was reviewed in many German and foreign scientific and popular journals. 325 of these reviews have been systematically analysed. They paint a representative picture of the book's contemporary reception. The analysis of the reviews helps to quantify the acceptance of the book among the German scientific community and shows how the reviewers created the image of the book as a standard work. Furthermore, the analysis elucidates the style of thinking that was prevalent among the reviewers.

  8. Ectoparasite occurrence associated with males and females of wild rodents Oligoryzomys flavescens (Waterhouse) and Akodon azarae (Fischer) (Rodentia: Cricetidae: Sigmodontinae) in the Punta Lara wetlands, Argentina.

    Science.gov (United States)

    Lareschi, Marcela

    2010-01-01

    The objective of this research was to study infestation parameters and indexes of ectoparasites associated with each sex of the wild rodents Oligoryzomys flavescens (Waterhouse) andAkodon azarae (Fischer) in the Punta Lara wetlands, Argentina. A trend towards higher mean abundance (MA) and ectoparasite specific richness was observed in males of O. flavescens whereas those values were similar for both A. azarae sexes. The prevalence of the following ectoparasites was significantly higher on males (Prodent hosts, these results are epidemiologically important.

  9. Nonvolatile Memory Based on Nonlinear Magnetoelectric Effects

    Science.gov (United States)

    Shen, Jianxin; Cong, Junzhuang; Chai, Yisheng; Shang, Dashan; Shen, Shipeng; Zhai, Kun; Tian, Ying; Sun, Young

    2016-08-01

    The magnetoelectric effects in multiferroics have a great potential in creating next-generation memory devices. We use an alternative concept of nonvolatile memory based, on a type of nonlinear magnetoelectric effects showing a butterfly-shaped hysteresis loop. The principle is to utilize the states of the magnetoelectric coefficient, instead of magnetization, electric polarization, or resistance, to store binary information. Our experiments in a device made of the PMN-PT/Terfenol-D multiferroic heterostructure clearly demonstrate that the sign of the magnetoelectric coefficient can be repeatedly switched between positive and negative by applying electric fields, confirming the feasibility of this principle. This kind of nonvolatile memory has outstanding practical virtues such as simple structure, easy operation in writing and reading, low power, fast speed, and diverse materials available.

  10. Research guidance studies to assess gasoline from coal by methanol-to-gasoline and sasol-type Fischer--Tropsch technologies. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Schreiner, M.

    1978-08-01

    This study provides a technical and economic comparison between the new Mobil methanol-to-gasoline technology under development and the commercially available Fischer--Tropsch technology for the production of motor gasoline meeting U.S. quality standards. Conceptual plant complexes, sited in Wyoming, are complete grass-roots facilities. The Lurgi dry-ash, pressure technology is used to gasify sub-bituminous strip coal. Except for the Mobil process, processes used are commercially available. Coproduction of products, namely SNG, LPG and gasoline, is practiced. Four sensitivity cases have also been developed in less detail from the two base cases. In all areas, the Mobil technology is superior to Fischer--Tropsch: process complexity, energy usage, thermal efficiency, gasoline selectivity, gasoline quality, investment and gasoline selectivity, gasoline quality, investment and gasoline cost. Principal advantages of the Mobil process are its selective yield of excellent quality gasoline with minimum ancillary processing. Fischer--Tropsch not only yields a spectrum of products, but the production of a gasoline meeting U.S. specifications is difficult and complex. This superiority results in about a 25% reduction in the gasoline cost. Sensitivity study conclusions include: (1) the conversion of methanol into gasoline over the Mobil catalyst is highly efficient, (2) if SNG is a valuable product, increased gasoline yield via the reforming of SNG is uneconomical, and (3) fluid-bed operation is somewhat superior to fixed-bed operation for the Mobil methanol conversion technology.

  11. The Heart and Great Vessels.

    Science.gov (United States)

    Onwuka, Ekene; King, Nakesha; Heuer, Eric; Breuer, Christopher

    2017-03-13

    Cardiovascular disease is the leading cause of mortality worldwide. We have made large strides over the past few decades in management, but definitive therapeutic options to address this health-care burden are still limited. Given the ever-increasing need, much effort has been spent creating engineered tissue to replaced diseased tissue. This article gives a general overview of this work as it pertains to the development of great vessels, myocardium, and heart valves. In each area, we focus on currently studied methods, limitations, and areas for future study. Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.

  12. Psychophysiology of prospective memory.

    Science.gov (United States)

    Rothen, Nicolas; Meier, Beat

    2014-01-01

    Prospective memory involves the self-initiated retrieval of an intention upon an appropriate retrieval cue. Cue identification can be considered as an orienting reaction and may thus trigger a psychophysiological response. Here we present two experiments in which skin conductance responses (SCRs) elicited by prospective memory cues were compared to SCRs elicited by aversive stimuli to test whether a single prospective memory cue triggers a similar SCR as an aversive stimulus. In Experiment 2 we also assessed whether cue specificity had a differential influence on prospective memory performance and on SCRs. We found that detecting a single prospective memory cue is as likely to elicit a SCR as an aversive stimulus. Missed prospective memory cues also elicited SCRs. On a behavioural level, specific intentions led to better prospective memory performance. However, on a psychophysiological level specificity had no influence. More generally, the results indicate reliable SCRs for prospective memory cues and point to psychophysiological measures as valuable approach, which offers a new way to study one-off prospective memory tasks. Moreover, the findings are consistent with a theory that posits multiple prospective memory retrieval stages.

  13. Human learning and memory.

    Science.gov (United States)

    Johnson, M K; Hasher, L

    1987-01-01

    There have been several notable recent trends in the area of learning and memory. Problems with the episodic/semantic distinction have become more apparent, and new efforts have been made (exemplar models, distributed-memory models) to represent general knowledge without assuming a separate semantic system. Less emphasis is being placed on stable, prestored prototypes and more emphasis on a flexible memory system that provides the basis for a multitude of categories or frames of reference, derived on the spot as tasks demand. There is increasing acceptance of the idea that mental models are constructed and stored in memory in addition to, rather than instead of, memorial representations that are more closely tied to perceptions. This gives rise to questions concerning the conditions that permit inferences to be drawn and mental models to be constructed, and to questions concerning the similarities and differences in the nature of the representations in memory of perceived and generated information and in their functions. There has also been a swing from interest in deliberate strategies to interest in automatic, unconscious (even mechanistic!) processes, reflecting an appreciation that certain situations (e.g. recognition, frequency judgements, savings in indirect tasks, aspects of skill acquisition, etc) seem not to depend much on the products of strategic, effortful or reflective processes. There is a lively interest in relations among memory measures and attempts to characterize memory representations and/or processes that could give rise to dissociations among measures. Whether the pattern of results reflects the operation of functional subsystems of memory and, if so, what the "modules" are is far from clear. This issue has been fueled by work with amnesics and has contributed to a revival of interaction between researchers studying learning and memory in humans and those studying learning and memory in animals. Thus, neuroscience rivals computer science as a

  14. Quantum Associative Memory

    CERN Document Server

    Ventura, D; Ventura, Dan; Martinez, Tony

    1998-01-01

    This paper combines quantum computation with classical neural network theory to produce a quantum computational learning algorithm. Quantum computation uses microscopic quantum level effects to perform computational tasks and has produced results that in some cases are exponentially faster than their classical counterparts. The unique characteristics of quantum theory may also be used to create a quantum associative memory with a capacity exponential in the number of neurons. This paper combines two quantum computational algorithms to produce such a quantum associative memory. The result is an exponential increase in the capacity of the memory when compared to traditional associative memories such as the Hopfield network. The paper covers necessary high-level quantum mechanical and quantum computational ideas and introduces a quantum associative memory. Theoretical analysis proves the utility of the memory, and it is noted that a small version should be physically realizable in the near future.

  15. Time for memory

    DEFF Research Database (Denmark)

    Murakami, Kyoko

    2012-01-01

    This article is a continuous dialogue on memory triggered by Brockmeier’s (2010) article. I drift away from the conventionalization of the archive as a spatial metaphor for memory in order to consider the greater possibility of “time” for conceptualizing memory. The concept of time is central...... in terms of autobiographical memory. The second category of time is discussed, drawing on Augustine and Bergson amongst others. Bergson’s notion of duration has been considered as a promising concept for a better understanding of autobiographical memory. Psychological phenomena such as autobiographical...... memory should embrace not only spatial dimension, but also a temporal dimension, in which a constant flow of irreversible time, where multiplicity, momentarily, dynamic stability and becoming and emergence of novelty can be observed....

  16. Regulatory T cell memory

    Science.gov (United States)

    Rosenblum, Michael D.; Way, Sing Sing; Abbas, Abul K.

    2016-01-01

    Memory for antigen is a defining feature of adaptive immunity. Antigen-specific lymphocyte populations show an increase in number and function after antigen encounter and more rapidly re-expand upon subsequent antigen exposure. Studies of immune memory have primarily focused on effector B cells and T cells with microbial specificity, using prime challenge models of infection. However, recent work has also identified persistently expanded populations of antigen-specific regulatory T cells that protect against aberrant immune responses. In this Review, we consider the parallels between memory effector T cells and memory regulatory T cells, along with the functional implications of regulatory memory in autoimmunity, antimicrobial host defence and maternal fetal tolerance. In addition, we discuss emerging evidence for regulatory T cell memory in humans and key unanswered questions in this rapidly evolving field. PMID:26688349

  17. Shape memory polymers

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Thomas S.; Bearinger, Jane P.

    2017-08-29

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  18. Shape memory polymers

    Science.gov (United States)

    Wilson, Thomas S.; Bearinger, Jane P.

    2015-06-09

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  19. Effects of promoters on catalytic performance of Fe-Co/SiO_2 catalyst for Fischer-Tropsch synthesis

    Institute of Scientific and Technical Information of China (English)

    Xiangdong Ma; Qiwen Sun; Weiyong Ying; Dingye Fang

    2009-01-01

    2%Fe-10%Co/SiO_2 catalysts with different potassium or zirconium Ioadings were prepared by aqueous incipient wetness impregnation and tested for Fischer-Tropsch synthesis in a flow reactor,using H_2/CO = 1.6 (molar ratio) in the feed,under the condition of an overall pressure of 1 MPa,GHSV of 600 h~(-1) and temperature of 503 K. The zirconium and potassium promoters remarkably influenced hydrocarbon distribution of the products. CO conversion increased on the catalysts with the increase of zirconium loadings,which indicated that zirconium enhanced the activity of iron-cobalt catalysts. Low potassium Ioadings also enhanced the activity of the catalysts. However,high potassium loading made CO conversion on the catalysts decrease and weakened the secondary hydrogenations. The catalyst was characterized by BET,XRD and TPR. The catalyst characterization revealed that the Co_3O_4 phase was presented on the fresh catalyst,whereas the spinel phase of Fe-Co alloy and CoO existed on the used catalyst.

  20. ANÁLISE MORFOLÓGICA DO APARELHO UNGUEAL DO VEADO-CATINGUEIRO (Mazama gouazoubira, Fischer, 1814 (Artiodactyla, Cervidae

    Directory of Open Access Journals (Sweden)

    Lorenna Cardoso Rezende

    2013-06-01

    Full Text Available The species studied in this research is known as gray brocketdeer. Two Mazama gouazoubira (Fischer, 1814 adult exemplars, donated to the Laboratory of Anatomy of Domestic and Wild Animals, Faculty of Veterinary Medicine, São Paulo University, were preserved in formaldehyde (10%. There are four ungulas or hulls on each member and they protect the distal end of the limb, covering the distal phalanx. The angle of the hoof was measured and samples of the digits were processed for light microscopy and scanning electron microscopy. In macroscopy, the length of the dorsal wall of the hoof measured approximately 2.5 cm, the angle formed at the step was 35° for the forelimb and 33° for the hindlimb. In microscopy, we could visualize the outer stratum as a very thin layer (141.5 μm, the middle stratum, composed of keratin tubular pigment, which is the main support structure of the wall of the hull, and the inner layer containing parallel slides in a longitudinal distribution, which is important to connect the hoof wall to the dorsal and lateral surface of the distal phalanx. The data from the ungular apparatus of the deers studied may help to elucidate the growth and identification of the footprints of these animals.

  1. Effect of chronic caloric restriction on physiological variables related to energy metabolism in the male Fischer 344 rat.

    Science.gov (United States)

    Duffy, P H; Feuers, R J; Leakey, J A; Nakamura, K; Turturro, A; Hart, R W

    1989-05-01

    In the present study, a number of physiological and behavioral measures that are related to metabolism were continuously monitored in 19-month-old male Fischer 344 rats that were fed ad libitum or fed a caloric restricted diet. Caloric restricted rats ate fewer meals but consumed more food during each meal and spent more time eating per meal than did rats fed ad libitum. Therefore, the timing and duration of meals as well as the total number of calories consumed may be associated with life extension. Average body temperature per day was significantly lower in restricted rats but body temperature range per day and motor activity were higher in restricted rats. Dramatic changes in respiratory quotient, indicating rapid changes in metabolic pathway and lower temperature, occurred in caloric restricted rats when carbohydrate reserves were depleted. Lower body temperature and metabolism during this time interval may result in less DNA damage, thereby increasing the survival potential of restricted rats. Nighttime feeding was found to synchronize physiological performance between ad libitum and caloric restricted rats better than daytime feeding, thereby allowing investigators to distinguish the effects of caloric restriction from those related solely to the time-of-day of feeding.

  2. Effect of Potassium Addition on Coprecipitated Iron Catalysts for Fischer-Tropsch Synthesis Using Bio-oil-syngas

    Institute of Scientific and Technical Information of China (English)

    Zhao-xiang Wang; Ting Dong; Tao Kan; Quan-xin Li

    2008-01-01

    The effects of potassium addition and the potassium content on the activity and selectivity of coprecipitated iron catalyst for Fischer-Tropsch synthesis (FTS) were studied in a fixed bed reactor at 1.5 MPa,300℃, and contact time (W/F) of 12.5 gcath/mol using the model bio-oil-syngas of H2/CO/CO2/N2 (62/8/25/5, vol%).It was found that potassium addition increases the catalyst activity for FTS and the reverse water gas shift reaction.Moreover,potassium increases the average molecular weight (chain length) of the hydrocarbon products.With the increase of potassium content,it was found that CH4 selectivity decreases and the selectivity of liquid phase products (C5+) increases.The characteristics of FTS catalysts with different potassium content were also investigated by various characterization measurements including X-ray diffraction,X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller surface area.Based on experimental results,100Fe/6Cu/16Al/6K (weight ratio) was selected as the optimal catalyst for FTS from bio-oil-syngas. The results indicate that the 100Fe/6Cu/16Al/6K catalyst is one of the most promising candidates to directly synthesize liquid bio-fuel using bio-oil-syngas.

  3. Performance characterization of CNTs and γ-Al2O3 supported cobalt catalysts in Fischer-Tropsch reaction

    Science.gov (United States)

    Ali, Sardar; Zabidi, Noor Asmawati Mohd; Subbarao, Duvvuri

    2014-10-01

    Catalysts were prepared via a wet impregnation method. Different physicochemical properties of the samples were revealed by transmission electron microscope (TEM), temperature programmed reduction (H2-TPR) and carbon dioxide desorption (CO2-desorption). Fischer-Tropsch reaction (FTS) was carried out in a fixed-bed microreactor at 220°C and 1 atm, with H2/ CO = 2v / v and space velocity, SV of 12L/g.h for 5 h. Various characterization techniques revealed that there was a stronger interaction between Co and Al2O3 support compared to that of CNTs support. CNTs support increased the reducibility and decreased Co particle size. A significant increase in % CO conversion and FTS reaction rate was observed over CNTs support compared to that of Co / Al2O3. Co/CNTs resulted in higher C5+ hydrocarbons selectivity compared to that of Co / Al2O3 catalyst. CNTs are a better support for Co compared to Al2O3.

  4. Comparison of PM emissions from a commercial jet engine burning conventional, biomass, and Fischer-Tropsch fuels.

    Science.gov (United States)

    Lobo, Prem; Hagen, Donald E; Whitefield, Philip D

    2011-12-15

    Rising fuel costs, an increasing desire to enhance security of energy supply, and potential environmental benefits have driven research into alternative renewable fuels for commercial aviation applications. This paper reports the results of the first measurements of particulate matter (PM) emissions from a CFM56-7B commercial jet engine burning conventional and alternative biomass- and, Fischer-Tropsch (F-T)-based fuels. PM emissions reductions are observed with all fuels and blends when compared to the emissions from a reference conventional fuel, Jet A1, and are attributed to fuel properties associated with the fuels and blends studied. Although the alternative fuel candidates studied in this campaign offer the potential for large PM emissions reductions, with the exception of the 50% blend of F-T fuel, they do not meet current standards for aviation fuel and thus cannot be considered as certified replacement fuels. Over the ICAO Landing Takeoff Cycle, which is intended to simulate aircraft engine operations that affect local air quality, the overall PM number-based emissions for the 50% blend of F-T fuel were reduced by 34 ± 7%, and the mass-based emissions were reduced by 39 ± 7%.

  5. Effect of Ag and Pd promotion on CH4 selectivity in Fe(100) Fischer-Tröpsch catalysis.

    Science.gov (United States)

    Psarras, Peter C; Wilcox, Jennifer; Ball, David W

    2017-02-15

    The current CO2 utilization market is dominated by enhanced oil recovery and urea manufacturing; yet, the scale of demand falls well short of that deemed necessary to make a significant impact on climate change. CO2 conversion to fuels, however, is a utilization technology that can theoretically match the scale of projected CO2 capture. Fischer-Tröpsch (FT) processing is a long-established technology for converting non-petroleum based precursors into transportation fuels and other valuable chemicals. Here, we report the effects of Pd and Ag doping on CH4 selectivity over Fe(100), a common FT catalyst, as these metals have shown potential in the direct conversion of co-fed CO2. Adsorption energies for pathway specific C1 and C2 species were weakened in the presence of Ag and Pd by ca. 0.55 eV and 0.35 eV, respectively. Further, while both Ag- and Pd-promoted surfaces show decreased CH4 production, Ag introduces a prohibitively high coupling barrier; thus, only Pd offered a decrease in CH4 selectivity (-36%) relative to unmodified Fe(100).

  6. The effects of promoters of K and Zr on the mesoporous carbon supported cobalt catalysts for Fischer-Tropsch synthesis.

    Science.gov (United States)

    Chen, Liang; Song, Guoxia; Fu, Yuchuan; Shen, Jianyi

    2012-02-15

    The mesoporous carbon supported cobalt catalyst (15%Co/MC) was found to be more active and selective to C(5)(+) than the traditionally activated carbon supported one (15%Co/AC) for the Fischer-Tropsch synthesis (FTS). The addition of small amount of K(2)O and ZrO(2) significantly affected the FTS behavior of 15%Co/MC. The addition of 1% K inhibited the FTS activity dramatically, while the addition of 3% Zr increased the FTS activity significantly. The addition of K(2)O decreased the surface acidity while increased the surface basicity of 15%Co/MC, resulting in the increased heat of adsorption of CO and substantially decreased heat of adsorption of H(2) on Co. In contrast, the addition of ZrO(2) increased the surface acidity and heat of adsorption of H(2) on Co. The FTS activity was found to be related to the ratio of heats for the adsorption of CO and H(2) on the catalysts 15%Co/MC, 15%Co-1%K/MC and 15%Co-3%Zr/MC. The highest FTS activity was obtained on the catalyst with the heat ratio of 1.2. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. Role of sialylation in determining the pharmacokinetics of neutrophil inhibitory factor (NIF) in the Fischer 344 rat.

    Science.gov (United States)

    Webster, R; Taberner, J; Edgington, A; Guhan, S; Varghese, J; Feeney, H; Blocker, L; Jezequel, S G

    1999-11-01

    1. Recombinant neutrophil inhibitory factor (NIF) is a glycoprotein. Its amino acid sequence remains constant and has a molecular weight of 28.9 kD. However, approximately 40% of the total molecular weight consists of glycans with variable structure. 2. The pharmacokinetics of 11 different NIF batches with varying extents and patterns of sialylation have been investigated in the Fischer 344 rat following intravenous administration. These data indicate that reducing the extent of NIF sialylation reduces the half-life of the molecule due to an increase in the systemic clearance. Also, an increase in the number of unsialylated or neutral glycans may increase the volume of distribution of NIF, although this effect is marginal. 3. Isolated perfused rat liver (IPRL) investigations have shown that sialylated NIF has a low hepatic extraction (NIF has an extraction that is > 20-fold higher. Co-administration of asialo NIF with asialo fetuin (a protein cleared by hepatic asialoglycoprotein receptor (possibly galactose)-mediated uptake reduced the hepatic extraction of asialo NIF. 4. These data suggest that NIF molecules that have free sugar moieties (possibly galactose) interact with an asialoglycoprotein receptor (possibly galactose-mediated) in the liver (parenchymal cells/hepatocytes). Interaction with this receptor leads to cellular internalization and degradation.

  8. Stress Alters the Discriminative Stimulus and Response Rate Effects of Cocaine Differentially in Lewis and Fischer Inbred Rats

    Directory of Open Access Journals (Sweden)

    Therese A. Kosten

    2012-03-01

    Full Text Available Stress enhances the behavioral effects of cocaine, perhaps via hypothalamic-pituitary-adrenal (HPA axis activity. Yet, compared to Fischer 344 (F344 rats, Lewis rats have hyporesponsive HPA axis function and more readily acquire cocaine self-administration. We hypothesized that stress would differentially affect cocaine behaviors in these strains. The effects of three stressors on the discriminative stimulus and response rate effects of cocaine were investigated. Rats of both strains were trained to discriminate cocaine (10 mg/kg from saline using a two-lever, food-reinforced (FR10 procedure. Immediately prior to cumulative dose (1, 3, 10 mg/kg cocaine test sessions, rats were restrained for 15-min, had 15-min of footshock in a distinct context, or were placed in the shock-paired context. Another set of F344 and Lewis rats were tested similarly except they received vehicle injections to test if stress substituted for cocaine. Most vehicle-tested rats failed to respond after stressor exposures. Among cocaine-tested rats, restraint stress enhanced cocaine’s discriminative stimulus effects in F344 rats. Shock and shock-context increased response rates in Lewis rats. Stress-induced increases in corticosterone levels showed strain differences but did not correlate with behavior. These data suggest that the behavioral effects of cocaine can be differentially affected by stress in a strain-selective manner.

  9. DOSE-DEPENDENT EFFECTS OF THE ANTIPROGESTIN, RU486, ON SEXUAL BEHAVIOR OF NATURALLY-CYCLING FISCHER RATS

    Science.gov (United States)

    Uphouse, Lynda

    2015-01-01

    Regularly cycling Fischer female rats were treated with either a low (5 mg/kg) or high (5 mg/RAT; approximately 30 mg/kg) dose of the antiprogestin, RU486, before the morning of proestrus or on the morning of proestrus. The emergence of sexual behavior after treatment with RU486 was examined in a mating test with a sexually active male rat. Lordosis behavior was remarkably resistant to the effects of RU486. Only the high dose of RU486 given the evening before proestrus, approximately 22 hours before mating, reduced lordosis behavior. Independent of dose or time of treatment, proceptivity was reduced and resistance to the male’s attempts to mount was increased by RU486 treatment. In addition, the effect of a 5 min restraint stress on sexual behavior was examined. In contrast to the relative resistance of lordosis behavior of unrestrained rats to RU486 treatment, RU486 treated rats showed a significant decline in lordosis behavior after restraint. These findings allow the suggestion that the emergence of lordosis behavior is relatively resistant to the antiprogestin while the maintenance of lordosis behavior after restraint may require participation of intracellular progesterone receptors. PMID:25591479

  10. Acute and rebound effects of lorazepam on orolingual motor function in young versus aged Fischer 344/Brown Norway rats.

    Science.gov (United States)

    Zhang, Hongyu; Stanford, John A

    2008-03-01

    The purpose of this study was to measure the acute effects of lorazepam [a short-acting benzodiazepine (BZ) with no active metabolites] on orolingual motor function in young (6 months) versus aged (24 months) Fischer 344/Brown Norway hybrid (F344/BN) rats. Rats licked water from an isometric force-sensing operandum so that the number of licks per session, licking rhythm (licks/second), and lick force could be measured during daily sessions. Acute doses (1.0 and 2.0 mg/kg) of lorazepam were administered 30 min before the testing sessions, 4 days apart. Whereas aged rats produced more licks per session, lorazepam increased this measure primarily in the young group. On the days after each lorazepam dose, rats licked less than they did before receiving the drug. This effect was shown by both groups. Aged rats showed significantly slower licking rhythm than young rats. Lorazepam slowed this measure in both groups. Peak tongue forces were significantly increased by lorazepam. These findings suggest that BZs such as lorazepam can affect tongue force output and exacerbate age-related tongue motility deficits. They also suggest that although BZs can directly influence motivation to engage in water-reinforced tasks, opposite 'rebound' effects may occur, even after acute dosing.

  11. OBTENCIÓN DE COMBUSTIBLES SINTÉTICOS, MEDIANTE LA REACCIÓN DE FISCHER TROPSCH, EMPLEANDO CATALIZADORES DE HIERRO

    Directory of Open Access Journals (Sweden)

    Rodrigo Rodríguez Cepeda

    2008-03-01

    Full Text Available Se prepararon una serie de catalizadores de hierro, sobre tres tipos diferentes de soporte: alúmina y dos tipos de carbón activado. A estos soportes se les adicionó potasio como promotor, y se les depositó paladio entre 0 y 1%, mediante el método de impregnación en exceso. Los catalizadores fueron caracterizados por adsorción de N2 a 77 K, Difracción de Rayos XRD y Reducción con Temperatura Programada, y se evaluaron bajo condiciones de la síntesis de Fischer Tropsch (FT. Se encontró que los catalizadores sintetizados sobre Carbón activado Eucalipto y Tagua, con la adición de paladio, desplazan la distribución de los productos hacia hidrocarburos líquidos, disminuyendo la fracción acuosa. Igualmente se muestra que los catalizadores soportados en alúmina, forman gases y una fracción acuosa como productos mayoritarios. Por otra parte, y de acuerdo con la distribución de probabilidad estadística (αp, de Schulz – Flory todos los catalizadores presentan hidrocarburos entre gasolina, diesel y ceras.   

  12. Purification Influence of Synthesis Gas Derived from Methanol Cracking on the Performance of Cobalt Catalyst in Fischer-Tropsch Synthesis

    Institute of Scientific and Technical Information of China (English)

    Wei Zhou; Shengying Liu; Yulan Wang; Kegong Fang; Jiangang Chen; Yuhan Sun

    2005-01-01

    Synthesis gas derived from methanol cracking (SGMC) was applied as simulating feedstock of Fischer-Tropsch synthesis (FTS) in laboratory. With MS and GC detector, a trifle of sulfur compounds,a small amount of oxygenates including H2O, CH3OH, DME and CO2 as well as a few of low carbon alkanes were found in the SGMC. After purification, the sulfur compounds, H2O, CH3OH and DME could be eliminated efficiently from the SGMC while CO2 and the low carbon alkanes were partly removed.When the unpurified SGMC, the desufurized SGMC and the totally purified SGMC were sequentially applied in cobalt-based FTS, the catalytic performance of Co/ZrO2/SiO2 catalyst was gradually improved corresponding to the degree of purification. The untreated SGMC led to the serious deactivation of the cobalt catalyst, the partially treated SGMC slowed down the deactivation rate and the totally purified SGMC resulted in little deactivation of the catalyst, which was similar to what the pure synthesis gas(the mixture of pure H2 and CO) did. The results indicated that the SGMC should be purified and the purification course used in this paper was effective for the SGMC. Furthermore, the totally purified SGMC could substitute for the pure synthesis gas in cobalt FTS.

  13. Isothermal Kinetics Modelling of the Fischer-Tropsch Synthesis over the Spray-Dried Fe-Cu-K Catalyst

    Institute of Scientific and Technical Information of China (English)

    Xiaohui Guo; Ying Liu; Jie Chang; Liang Bai; Yuanyuan Xu; Hongwei Xiang; Yongwang Li

    2006-01-01

    The isothermal kinetics of the Fischer-Tropsch synthesis (FTS) over Fe-Cu-K spray-dried catalyst was studied in a spinning basket reactor. The experiments were carried out at a constant temperature of 523 K, n(H2)/n(CO) feed ratios of 0.8-2.0, reactor pressures of 1.1-2.5 MPa, and space velocity of 0.556× 10-3 Nm3/kgcat.s. Kinetic model for hydrocarbon formation was derived on the basis of simplified carbide mechanism to reduce the number of parameters. Two individual rate constants for methane and ethene were considered. Furthermore, the model was modified empirically by non-intrinsic effect, such as physisorption and fictitious olefin pressures that were taken into account, and the influences of secondary reaction of α-olefins on product distribution. The simulation results showed that the experimental phenomena of FTS and the deviations from ASF distribution, such as the relatively high yield of methane and low yield of ethene observed experimentally could be depicted basically.

  14. Efficiency of methods for Karl Fischer determination of water in oils based on oven evaporation and azeotropic distillation.

    Science.gov (United States)

    Larsson, William; Jalbert, Jocelyn; Gilbert, Roland; Cedergren, Anders

    2003-03-15

    The efficiency of azeotropic distillation and oven evaporation techniques for trace determination of water in oils has recently been questioned by the National Institute of Standards and Technology (NIST), on the basis of measurements of the residual water found after the extraction step. The results were obtained by volumetric Karl Fischer (KF) titration in a medium containing a large excess of chloroform (> or = 65%), a proposed prerequisite to ensure complete release of water from the oil matrix. In this work, the extent of this residual water was studied by means of a direct zero-current potentiometric technique using a KF medium containing more than 80% chloroform, which is well above the concentration recommended by NIST. A procedure is described that makes it possible to correct the results for dilution errors as well as for chemical interference effects caused by the oil matrix. The corrected values were found to be in the range of 0.6-1.5 ppm, which should be compared with the 12-34 ppm (uncorrected values) reported by NIST for the same oils. From this, it is concluded that the volumetric KF method used by NIST gives results that are much too high.

  15. Anthocyanin-Rich Juice Lowers Serum Cholesterol, Leptin, and Resistin and Improves Plasma Fatty Acid Composition in Fischer Rats.

    Directory of Open Access Journals (Sweden)

    Daniela Graf

    Full Text Available Obesity and obesity-associated diseases e.g. cardiovascular diseases and type 2 diabetes are spread worldwide. Anthocyanins are supposed to have health-promoting properties, although convincing evidence is lacking. The aim of the present study was to investigate the effect of anthocyanins on several risk factors for obesity-associated diseases. Therefore, Fischer rats were fed anthocyanin-rich grape-bilberry juice or an anthocyanin-depleted control juice for 10 weeks. Intervention with anthocyanin-rich grape-bilberry juice reduced serum cholesterol and tended to decrease serum triglycerides. No effects were seen for serum non-esterified fatty acids, glucose, and insulin. Anthocyanin-rich grape-bilberry juice intervention reduced serum leptin and resistin, but showed no influence on serum adiponectin and secretion of adipokines from mesenteric adipose tissue. Furthermore, anthocyanin-rich grape-bilberry juice increased the proportion of polyunsaturated fatty acids and decreased the amount of saturated fatty acids in plasma. These results indicate that anthocyanins possess a preventive potential for obesity-associated diseases.

  16. Studies on accelerated deactivation of ruthenium-promoted alumina-supported alkalized cobalt Fischer-Tropsch synthesis catalyst

    Institute of Scientific and Technical Information of China (English)

    Shohreh Tehrani; Mohamad Irani; Ahmad Tavasoli; Yadollah Mortazavi; Abbas A.Khodadadi; Ali Nakhaei Pour

    2011-01-01

    Accelerated deactivation of ruthenium-promoted alumina-supported alkalized cobalt(K-Ru-Co/-γ-Al2O3)Fischer-Tropsch(FT)synthesis catalyst along the catalytic bed over 120 h of time-on-stream(TOS)was investigated.Catalytic bed was divided into three parts and structural changes of the spent catalysts collected from each catalytic bed after FT synthesis were studied using different techniques.Rapid deactivation was observed during the reaction due to high reaction temperature and low feed flow rates.The physico-chemical properties of the catalyst charged in the Bed #1 of the reactor did not change significantly.Interaction of cobalt with alumina and the formation of CoAl2O4 increased along the catalytic bed.Reducibility percentage decreased by 4.5%,7.5% and 12.9% for the catalysts in the Beds #1,#2 and #3,respectively.Dispersion decreased by 8.8%,14.4% and 26.6% for the catalysts in the Beds #1,#2 and #3,respectively.Particle diameter increased by 0.6%,2.4% and 10.4% for the catalysts in the Beds #1,#2 and #3,respectively,suggesting higher rate of sintering at the last catalytic bed.The amount of coke at the last catalytic bed was significantly higher than those of Beds #1 and #2.

  17. Incorporation of Reaction Kinetics into a Multiphase, Hydrodynamic Model of a Fischer Tropsch Slurry Bubble Column Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Donna Guillen, PhD; Anastasia Gribik; Daniel Ginosar, PhD; Steven P. Antal, PhD

    2008-11-01

    This paper describes the development of a computational multiphase fluid dynamics (CMFD) model of the Fischer Tropsch (FT) process in a Slurry Bubble Column Reactor (SBCR). The CMFD model is fundamentally based which allows it to be applied to different industrial processes and reactor geometries. The NPHASE CMFD solver [1] is used as the robust computational platform. Results from the CMFD model include gas distribution, species concentration profiles, and local temperatures within the SBCR. This type of model can provide valuable information for process design, operations and troubleshooting of FT plants. An ensemble-averaged, turbulent, multi-fluid solution algorithm for the multiphase, reacting flow with heat transfer was employed. Mechanistic models applicable to churn turbulent flow have been developed to provide a fundamentally based closure set for the equations. In this four-field model formulation, two of the fields are used to track the gas phase (i.e., small spherical and large slug/cap bubbles), and the other two fields are used for the liquid and catalyst particles. Reaction kinetics for a cobalt catalyst is based upon values reported in the published literature. An initial, reaction kinetics model has been developed and exercised to demonstrate viability of the overall solution scheme. The model will continue to be developed with improved physics added in stages.

  18. Sulphur poisoning of a Co/Al{sub 2}O{sub 3} Fischer-Tropsch catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Visconti, C.G.; Lietti, L.; Forzatti, P. [Politecnico di Milano (Italy). Dipt. di Chimica, Materiali e Ingegneria Chimica ' Giulio Natta' ; Zennaro, R. [Eni, San Donato Milanese (Italy). Div. Refining and Marketing

    2007-07-01

    The effect of sulphur poisoning (in the range 0-2000 ppm) on the characteristics and catalytic performances in the Fischer-Tropsch synthesis of a bench-scale alumina supported cobalt catalyst was investigated in this study. It was found that sulphur does not lead to appreciable variations in the catalyst morphological characteristics; however the catalyst reducibility and hydrogenating capabilities are significantly modified upon increasing the S-loading. The comparison between the catalytic performances of the sulphured samples pointed out that the S-presence remarkably affects the productivity and the selectivity of the reaction. In particular for S-amounts lower than 100 ppm the CO conversion is decreased whereas the product distribution is not significantly affected; at higher S-loadings, on the contrary, a significant decrease in the formation of heavier products is observed along with a decrease in CO conversion. This leads to significant changes in the selectivity of the reaction. These effects had been tentatively associated with different S-effects on the catalyst active sites, i.e. on the sites responsible for CO hydrogenation and for the chain growth process. Finally the experimental data of CO conversion decay with S-loading were described according to a simple deactivation model which implies a strong S-effect on the catalyst active sites. (orig.)

  19. Organic Analysis of Catalytic Fischer-Tropsch Type Synthesis Products: Are they Similar to Organics in Chondritic Meteorites?

    Science.gov (United States)

    Yazzie, Cyriah A.; Locke, Darren R.; Johnson, Natasha M.

    2014-01-01

    Fischer-Tropsch Type (FTT) synthesis of organic compounds has been hypothesized to occur in the early solar nebula that formed our Solar System. FTT is a collection of abiotic chemical reactions that convert a mixture of carbon monoxide and hydrogen over nano-catalysts into hydrocarbons and other more complex aromatic compounds. We hypothesized that FTT can generate similar organic compounds as those seen in chondritic meteorites; fragments of asteroids that are characteristic of the early solar system. Specific goals for this project included: 1) determining the effects of different FTT catalyst, reaction temperature, and cycles on organic compounds produced, 2) imaging of organic coatings found on the catalyst, and 3) comparison of organic compounds produced experimentally by FTT synthesis and those found in the ordinary chondrite LL5 Chelyabinsk meteorite. We used Pyrolysis Gas Chromatography Mass Spectrometry (PY-GCMS) to release organic compounds present in experimental FTT and meteorite samples, and Scanning Electron Microscopy (SEM) to take images of organic films on catalyst grains.

  20. Incorporation of Reaction Kinetics into a Multiphase, Hydrodynamic Model of a Fischer Tropsch Slurry Bubble Column Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Donna Guillen, PhD; Anastasia Gribik; Daniel Ginosar, PhD; Steven P. Antal, PhD

    2008-11-01

    This paper describes the development of a computational multiphase fluid dynamics (CMFD) model of the Fischer Tropsch (FT) process in a Slurry Bubble Column Reactor (SBCR). The CMFD model is fundamentally based which allows it to be applied to different industrial processes and reactor geometries. The NPHASE CMFD solver [1] is used as the robust computational platform. Results from the CMFD model include gas distribution, species concentration profiles, and local temperatures within the SBCR. This type of model can provide valuable information for process design, operations and troubleshooting of FT plants. An ensemble-averaged, turbulent, multi-fluid solution algorithm for the multiphase, reacting flow with heat transfer was employed. Mechanistic models applicable to churn turbulent flow have been developed to provide a fundamentally based closure set for the equations. In this four-field model formulation, two of the fields are used to track the gas phase (i.e., small spherical and large slug/cap bubbles), and the other two fields are used for the liquid and catalyst particles. Reaction kinetics for a cobalt catalyst is based upon values reported in the published literature. An initial, reaction kinetics model has been developed and exercised to demonstrate viability of the overall solution scheme. The model will continue to be developed with improved physics added in stages.