WorldWideScience

Sample records for in-class ceo intervention

  1. Measuring Teacher Implementation of the "BEST in CLASS" Intervention Program and Corollary Child Outcomes

    Science.gov (United States)

    Conroy, Maureen A.; Sutherland, Kevin S.; Algina, James J.; Wilson, Reynolds E.; Martinez, Jose R.; Whalon, Kelly J.

    2015-01-01

    This study is part of a larger randomized efficacy trial examining the impact of Behavioral, Emotional, and Social Training: Competent Learners Achieving School Success ("BEST in CLASS"), a Tier 2 intervention that targets the prevention of emotional/behavioral disorders in young, high risk children. In this investigation, we examined…

  2. The Market for CEOs

    DEFF Research Database (Denmark)

    Aivazian, Varouj A.; Lai, Tat-kei; Rahaman, Mohammad M.

    2013-01-01

    We investigate empirically a market-based explanation for the rise in recent years in external CEO hiring and compensation and find, consistent with the market-based theory, that firms in industries relying on general managerial skills are more likely to hire CEOs externally than firms...... in industries relying less on such skills. We show that firms relying on internal CEOs have on average higher profits than external-CEO firms and that the difference in profits decreases as general skills become more important in the industry. We relate managerial skills to compensation and show that CEO...

  3. Aging IQ Intervention with Older Korean Americans: A Comparison of Internet-Based and In-Class Education

    Science.gov (United States)

    Jang, Yuri; Yoon, Hyunwoo; Marti, C. Nathan; Kim, Miyong T.

    2015-01-01

    Using the translated contents of the National Institute on Aging (NIA)'s Aging IQ, an educational intervention was delivered to older Korean Americans. The educational program was delivered via two different modalities, Internet-based education (n = 12) and in-class education (n = 11), and the overall feasibility and efficacy were evaluated by the…

  4. CEOS precipitation constellation

    Science.gov (United States)

    Neeck, Steven P.; Oki, Riko

    2007-10-01

    The outcomes of the 19th Committee on Earth Observing Satellites (CEOS) Plenary held in London in November 2005, recognized that the CEOS Implementation Plan for Space-Based Observations for Global Earth Observation System of Systems (GEOSS) should: - identify the supply of space-based observations required to satisfy the requirements expressed by the 10-year implementation plan for GEOSS; and - propose an innovative process whereby the many disparate types of Earth observing programs funded by CEOS Member agencies might contribute to the supply of the required observations. The CEOS Task Force charged with drafting the CEOS Implementation Plan for Space-Based Observations for GEOSS focused its early efforts on the creation of a 'new planning process' which would satisfy the various criteria demanded by member space agencies, and which would hopefully encourage a new phase of specificity and focus in the multi-lateral co-operation efforts undertaken by space agencies under the CEOS umbrella - resulting in improved engagement of all CEOS Members and real implementation results. The CEOS Constellations is the title given to this new process, and four pilot studies have been initiated in order to pioneer and test the concept. The Japan Aerospace Exploration Agency (JAXA) and the National Aeronautics and Space Administration (NASA) were selected as the lead agencies for the study of the development of a CEOS Precipitation Constellation with the support of other CEOS space agency and user community participants. The goals, approach, and anticipated outcomes for the study will be discussed.

  5. Cooperative CEO Identity and Efficient Governance: Member or Outside CEO?

    NARCIS (Netherlands)

    Q.X. Liang (Qiao Xin); G.W.J. Hendrikse (George)

    2012-01-01

    textabstractA principal-agent model is formulated to capture the efficiency of cooperatives with a member CEO and cooperatives with an employed outsider as CEO. Results of the model show that the incentive strength regarding the member CEO is stronger compared to that of the outside CEO in order to

  6. Are CEOs Different?

    DEFF Research Database (Denmark)

    Kaplan, Steven N.; Sørensen, Morten

    We use a data set of over 2,600 executive assessments to study thirty individual characteristics of candidates for top executive positions – CEO, CFO, COO and others. Candidate characteristics can be classified by four primary factors: general ability, execution skills, charisma and strategic...... also predict future career progression. Non-CEO candidates who score higher on the four factors are subsequently more likely to become CEOs. The patterns are qualitatively similar for public, private equity and venture capital owned companies. We do not find economically large differences in the four...

  7. Are CEOs Different?

    DEFF Research Database (Denmark)

    Kaplan, Steven N.; Sørensen, Morten

    We use a data set of over 2,600 executive assessments to study thirty individual characteristics of candidates for top executive positions – CEO, CFO, COO and others. Candidate characteristics can be classified by four primary factors: general ability, execution skills, charisma and strategic ski...... factors for men and women. Women, however, are ultimately less likely to become CEOs holding the four factors constant....

  8. Finding your next CEO.

    Science.gov (United States)

    Thrall, Terese Hudson

    2008-12-01

    Hospital CEOs spend an average of just six years at one organization, and the cost of turnover is high. Finding executives to fill that top spot is more complicated thanks to a jittery economy, job candidates' worries about selling their homes and other issues. That's prompting hospitals to be more flexible in their recruitment efforts: considering older candidates, reviving succession planning, and even buying and selling CEOs' houses.

  9. Are CEOs Different?

    DEFF Research Database (Denmark)

    Kaplan, Steven N.; Sørensen, Morten

    We use a dataset of over 2,600 executive assessments to study thirty individual characteristics ofcandidates for top executive positions – CEO, CFO, COO and others. We classify the thirtycandidate characteristics with four primary factors: general ability, execution vs. interpersonal,charisma vs...... on the four factors also predict future career progression. Non-CEOcandidates who score higher on the four factors are subsequently more likely to become CEOs.The patterns are qualitatively similar for public, private equity and venture capital ownedcompanies. We do not find economically large differences...

  10. The Principal as CEO

    Science.gov (United States)

    Hollar, Charlie

    2004-01-01

    They may never grace the pages of The Wall Street Journal or Fortune magazine, but they might possibly be the most important CEOs in our country. They are elementary school principals. Each of them typically serves the learning needs of 350-400 clients (students) while overseeing a multimillion-dollar facility staffed by 20-25 teachers and 10-15…

  11. The CEO's second act.

    Science.gov (United States)

    Nadler, David A

    2007-01-01

    When a CEO leaves because of performance problems, the company typically recruits someone thought to be better equipped to fix what the departing executive couldn't--or wouldn't. The board places its confidence in the new person because of the present dilemma's similarity to some previous challenge that he or she dealt with successfully. But familiar problems are inevitably succeeded by less familiar ones, for which the specially selected CEO is not quite so qualified. More often than not, the experiences, skills, and temperament that yielded triumph in Act I turn out to be unequal to Act II's difficulties. In fact, the approaches that worked so brilliantly in Act I may be the very opposite of what is needed in Act II. The CEO has four choices: refuse to change, in which case he or she will be replaced; realize that the next act requires new skills and learn them; downsize or circumscribe his or her role to compensate for deficiencies; or line up a successor who is qualified to fill a role to which the incumbent's skills and interests are no longer suited. Hewlett-Packard's Carly Fiorina exemplifies the first alternative; Merrill Lynch's Stanley O'Neal the second; Google's Sergey Brin and Larry Page the third; and Quest Diagnostics' Ken Freeman the fourth. All but the first option are reasonable responses to the challenges presented in the second acts of most CEOs' tenures. And all but the first require a power of observation, a propensity for introspection, and a strain of humility that are rare in the ranks of the very people who need those qualities most. There are four essential steps executives can take to discern that they have entered new territory and to respond accordingly: recognition that their leadership style and approach are no longer working; acceptance of others' advice on why performance is faltering; analysis and understanding of the nature of the Act II shift; and, finally, decision and action.

  12. CEO overconfidence and cost stickiness

    OpenAIRE

    Qin, B.; Mohan, A.W.; Kuang, Y.F.

    2015-01-01

    Cost stickiness occurs when costs decrease less when sales fall than they increase when sales rise. Prior literature provides both economic and agency explanations of sticky costs. Our study tackles this cost behaviour from a managerial behavioural perspective. We predict and find that cost stickiness is greater when firms are managed by overconfident CEOs. The results are consistent with the notion that overconfident CEOs are more likely to exhibit an optimistic bias and tend to be overly po...

  13. Does CEO compensation impact patient satisfaction?

    Science.gov (United States)

    Akingbola, Kunle; van den Berg, Herman A

    2015-01-01

    This study examines the relationship between CEO compensation and patient satisfaction in Ontario, Canada. The purpose of this paper is to determine what impact hospital CEO compensation has on hospital patient satisfaction. The analyses in this study were based on data of 261 CEO-hospital-year observations in a sample of 103 nonprofit hospitals. A number of linear regressions were conducted, with patient satisfaction as the dependent variable and CEO compensation as the independent variable of interest. Controlling variables included hospital size, type of hospital, and frequency of adverse clinical outcomes. CEO compensation does not significantly influence hospital patient satisfaction. Both patient satisfaction and CEO compensation appear to be driven primarily by hospital size. Patient satisfaction decreases, while CEO compensation increases, with the number of acute care beds in a hospital. In addition, CEO compensation does not even appear to moderate the influence of hospital size on patient satisfaction. There are several limitations to this study. First, observations of CEO-hospital-years in which annual nominal CEO compensation was below $100,000 were excluded, as they were not publicly available. Second, this research was limited to a three-year range. Third, this study related the compensation of individual CEOs to a measure of performance based on a multitude of patient satisfaction surveys. Finally, this research is restricted to not-for-profit hospitals in Ontario, Canada. The findings seem to suggest that hospital directors seeking to improve patient satisfaction may find their efforts frustrated if they focus exclusively on the hospital CEO. The findings highlight the need for further research on how CEOs may, through leading and supporting those hospital clinicians and staff that interact more closely with patients, indirectly enhance patient satisfaction. To the best of the authors' knowledge, no research has examined the relationship between

  14. CEOS SEO and GISS Meeting

    Science.gov (United States)

    Killough, Brian; Stover, Shelley

    2008-01-01

    The Committee on Earth Observation Satellites (CEOS) provides a brief to the Goddard Institute for Space Studies (GISS) regarding the CEOS Systems Engineering Office (SEO) and current work on climate requirements and analysis. A "system framework" is provided for the Global Earth Observation System of Systems (GEOSS). SEO climate-related tasks are outlined including the assessment of essential climate variable (ECV) parameters, use of the "systems framework" to determine relevant informational products and science models and the performance of assessments and gap analyses of measurements and missions for each ECV. Climate requirements, including instruments and missions, measurements, knowledge and models, and decision makers, are also outlined. These requirements would establish traceability from instruments to products and services allowing for benefit evaluation of instruments and measurements. Additionally, traceable climate requirements would provide a better understanding of global climate models.

  15. CEO Education and Corporate Environmental Footprint

    DEFF Research Database (Denmark)

    Amore, Mario Daniele; Bennedsen, Morten; Larsen, Birthe

    We analyze the effect of CEO education on environmental decision-making. Using a unique sample of Danish firms from 1996 to 2012, we find that CEO education significantly improves firms’ energy efficiency. We derive causality using health shocks: the hospitalization of highly educated CEOs induces...... environmental awareness: highly educated CEOs exhibit greater concerns for climate change, as measured by a survey of social preferences, and drive more environmentally-efficient cars. Taken together, our findings suggest that education shapes managerial styles giving rise to greater sustainability in corporate...... a drop in energy efficiency, whereas the hospitalization of less educated CEOs does not have any significant effect. Exploring the mechanisms at play, we show that our results are driven by the length rather than the field of education. CEO education improves corporate energy efficiency through personal...

  16. CEO compensation and hospital financial performance.

    Science.gov (United States)

    Reiter, Kristin L; Sandoval, Guillermo A; Brown, Adalsteinn D; Pink, George H

    2009-12-01

    Growing interest in pay-for-performance and the level of chief executive officers' (CEOs') pay raises questions about the link between performance and compensation in the health sector. This study compares the compensation of nonprofit hospital CEOs in Ontario, Canada to the three longest reported and most used measures of hospital financial performance. Our sample consisted of 132 CEOs from 92 hospitals between 1999 and 2006. Unbalanced panel data were analyzed using fixed effects regression. Results suggest that CEO compensation was largely unrelated to hospital financial performance. Inflation-adjusted salaries appeared to increase over time independent of hospital performance, and hospital size was positively correlated with CEO compensation. The apparent upward trend in salary despite some declines in financial performance challenges the fundamental assumption underlying this article, that is, financial performance is likely linked to CEO compensation in Ontario. Further research is needed to understand long-term performance related to compensation incentives.

  17. CEO Education and Corporate Environmental Footprint

    DEFF Research Database (Denmark)

    Amore, Mario Daniele; Bennedsen, Morten; Larsen, Birthe

    environmental awareness: highly educated CEOs exhibit greater concerns for climate change, as measured by a survey of social preferences, and drive more environmentally-efficient cars. Taken together, our findings suggest that education shapes managerial styles giving rise to greater sustainability in corporate......We analyze the effect of CEO education on environmental decision-making. Using a unique sample of Danish firms from 1996 to 2012, we find that CEO education significantly improves firms’ energy efficiency. We derive causality using health shocks: the hospitalization of highly educated CEOs induces...

  18. CEO origin and accrual-based earnings management

    NARCIS (Netherlands)

    Kuang, Y.F.; Qin, B.; Wielhouwer, J.

    2014-01-01

    This study examines the influence of CEO origin on accrual-based earnings management and how these effects evolve over the CEO's tenure in office. Compared with CEOs promoted from within the company, CEOs recruited from outside have a stronger incentive to demonstrate their abilities in the initial

  19. Nevo sebáceo

    Directory of Open Access Journals (Sweden)

    Clara García Lahera

    2014-08-01

    Full Text Available El nevo sebáceo es un hamartoma verrugoso, por lo general bien circunscrito, que aparece en muchas ocasiones con el nacimiento, localizado principalmente en la cabeza, en el cuero cabelludo. Se puede observar en el 0,3% de todos los neonatos y afecta por igual a ambos sexos. Se relaciona con múltiples tumores benignos y malignos, además constituye una facomatosis, que conlleva a la asociación de esta lesión congénita con varias alteraciones neurológicas, como son el retraso mental y la epilepsia. Se presenta el caso por ser poco frecuente la aparición de esta entidad dermatológica

  20. CEO Overconfidence, Leadership Ethics, and Institutional Investors

    Directory of Open Access Journals (Sweden)

    Joohee Park

    2016-12-01

    Full Text Available This paper explores the influence of institutional investors’ external monitoring on CEOs’ overconfidence. We particularly examine institutional monitoring’s influence on overinvestments by overconfident CEOs and the likelihood of appointing these overconfident CEOs to firms. The results indicate that firms with overconfident CEOs have more overinvestment, as the CEOs tend to be overly optimistic about investment opportunities and are more likely to act on them. The findings, more importantly, show that institutional monitoring mechanisms attenuate overconfident CEOs’ overinvestment. However, we find that institutional monitoring is only significant when long-term and/or large institutional investors hold the firms’ shares. We also discover that investors’ institutional monitoring not only actively reduces a CEO’s overinvestments, but also negatively influences the appointment of overconfident CEOs. Overall, our study provides insights into institutional monitoring’s role in corporate governance as an effective means of preventing value-destroying behaviors by an overconfident leader and cultivating an ethical business philosophy.

  1. The relationship between virtuous CEOs and corporate social responsibility

    OpenAIRE

    Frende Vega, María de los Ángeles; Carmelo Ordaz, Carmen; Ruiz Navarro, José

    2014-01-01

    This study tests the effects of virtuous CEOs on corporate social responsibility views (narrow vs broad). Using the data envelopment analysis (DEA) technique, we find that virtuous CEOs correlated positively with a broad view of corporate social responsibility (CSR). We also examine the moderating role the board of directors plays in the relationship between virtuous CEOs and CSR but finds no positive association. Our results indicate that CEOs matter and that their virtuous values may be a m...

  2. New CEO origin and Firm Performance: A Multilevel Investigation

    OpenAIRE

    Georgakakis, Dimitrios; Ruigrok, Winfried

    2014-01-01

    In this study we develop a multilevel research framework, postulating that the performance implications of outside CEO succession depend on the individual level characteristics of the new CEO, and the organizational and environmental level contingencies facing the company. First, drawing on relational demography and information processing theories, the study focuses on two types of individual level CEO characteristics: (a) relational socio-demographic attributes (i.e., CEO-TMT socio-demograph...

  3. Facile hydrothermal synthesis of CeO2 nanopebbles

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Cerium oxide (CeO2) nanopebbles have been synthesized using a facile hydrothermal method. X-ray diffraction pattern (XRD) and transmission electron microscopy analyses confirm the presence of CeO2 nanopebbles. XRD shows the formation of cubic fluorite CeO2 and the average particle size estimated from.

  4. CEO Succession in Community Colleges: A Grounded Theory.

    Science.gov (United States)

    Kirkland, Travis P.

    Intended as part of a larger study of the effects of anticipated or unanticipated changes in the chief executive officer (CEO) of a community college, a case study approach was taken to gather primary data from a multi-campus, urban community college that had recently experienced a CEO succession. The study focused on the effects of the CEO change…

  5. Hospital CEO's viewpoint for future of health care marketing.

    Science.gov (United States)

    Cox, V

    1990-01-01

    In summary, the CEOs have a wide variety of views on what role the marketer will play and what needs the marketer will fill for the CEO. It is important for the marketer to clarify the expected roles as they interview for jobs. Once in the position, it is important to keep communications open with the CEO to know the marketer's expected role.

  6. CEO Origin and Accrual-Based Earnings Management

    NARCIS (Netherlands)

    Kuang, Y.; Qin, B.; Wielhouwer, J.L.

    2014-01-01

    This study examines the influence of CEO origin on accrual-based earnings management and how these effects evolve over the CEO’s tenure in office. Compared with CEOs promoted from within the company, CEOs recruited from outside have a stronger incentive to demonstrate their abilities in the initial

  7. PENGGUNAAN LEVERAGE PADA PERUSAHAAN: PERBEDAAN ANTARA CEO PRIA DAN WANITA

    Directory of Open Access Journals (Sweden)

    Farida Titik Kritanti

    2014-07-01

    Full Text Available AbstractVarious studies show that women are more risk averse in making decisions and better long-term oriented. Women would rather risk averse than men, making it less likely they will use debt in their capital structure, since by increasing debt increases the risk of the company's financial means. This study want to test whether gender became a significant factor in financial leverage, to see whether there are differences in policy between the company's leverage, led by men and women. Financial leverage is used as a measure of corporate risk because these variables can be changed by the CEO. Data from companies listed on the Jakarta Stock Exchange as sample. The results showed that there were differences in leverage between firms that have a men CEO with the women CEO of a company. Men CEO use more debt than the women CEO. But for the performance measured by ROI, obtained different results for the type of industry studied. For the consumer goods industry, there are performance differences between the men CEO and the women. But for the internet service industry and enamel kitchen showed no performance difference between women CEO with men CEO.Key words: leverage, woman CEO, man CEO, performanceAbstrakBerbagai penelitian menunjukkan bahwa wanita lebih risk averse dalam mengambil keputusan dan lebih berorientasi jangka panjang. Wanita lebih suka menolak risiko dibandingkan pria, sehingga kecil kemungkinan mereka akan menggunakan hutang dalam struktur modalnya, karena dengan menambah hutang berarti memperbesar risiko keuangan perusahaan. Penelitian ini ingin menguji apakah jender menjadi faktor yang cukup signifikan dalam financial leverage, dengan melihat apakah ada perbedaan dalam kebijakan leverage antara perusahaan yang dipimpin oleh pria dan wanita. Financial leverage dipakai sebagai ukuran risiko perusahaan karena variabel ini bisa diubah oleh CEO. Sampel menggunakan data dari perusahaan yang listed di Jakarta Stock Exchange. Hasil penelitian

  8. Corporate governance and CEO pay: Evidence from UK Travel and Leisure listed firms

    OpenAIRE

    Al-Najjar, Basil

    2017-01-01

    This paper investigates from the UK context, the impact of board and CEO characteristics on CEO compensation in Travel and Leisure firms. Namely we employ, board size, board independence and board meetings to reflect board characteristics. We also include two CEO features, CEO tenure and CEO age into our models. Using panel data analysis, the findings in this paper indicate that board size, board independence and CEO age are important factors affecting CEO pay. In addition, we report a positi...

  9. Do women CEOs face greater threat of shareholder activism compared to male CEOs? A role congruity perspective.

    Science.gov (United States)

    Gupta, Vishal K; Han, Seonghee; Mortal, Sandra C; Silveri, Sabatino Dino; Turban, Daniel B

    2018-02-01

    We examine the glass cliff proposition that female CEOs receive more scrutiny than male CEOs, by investigating whether CEO gender is related to threats from activist investors in public firms. Activist investors are extraorganizational stakeholders who, when dissatisfied with some aspect of the way the firm is being managed, seek to change the strategy or operations of the firm. Although some have argued that women will be viewed more favorably than men in top leadership positions (so-called "female leadership" advantage logic), we build on role congruity theory to hypothesize that female CEOs are significantly more likely than male CEOs to come under threat from activist investors. Results support our predictions, suggesting that female CEOs may face additional challenges not faced by male CEOs. Practical implications and directions for future research are discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  10. Views of CEOs on Firm Performance

    Directory of Open Access Journals (Sweden)

    Dario Berginc

    2014-11-01

    Full Text Available Researching the managerial perspective of performance can contribute to a better understanding of firm performance, and offer a valuable contribution to research on objective performance measurement. The aim of this article is to examine how managers evaluate firm performance and which factors, in their opinion, have the biggest influence on performance. We particularly wanted to investigate the influence of top management and owners on firm performance. We conducted a qualitative study among the CEOs of some of the most successful Slovenian firms. The results show that CEOs connect positive performance with long-term growth and satisfying the needs of key stakeholders (employees, customers and owners, but short-term positive financial performance represents the basic foundation. The second most important factor is a united top management, capable of generating new ideas and acting as a role model to employees. This can lead to a higher degree of engagement by employees and a better understanding of the firm's goals. Owners can contribute to a positive firm performance with their active, strategic and long-term orientation, and with their ability to set clear goals and to trust top management in the long run. Another important factor that influences firm performance is the ownership structure. In the opinion of CEOs, dominant and private ownership has a more positive impact on firm performance than dispersed and state ownership. The present research findings provide several examples of good and bad practice, and highlight opportunities for further research, from an in-depth study of individual factors of firm performance to the search for a more comprehensive model of performance factors, based on a larger sample of CEOs and other managers.

  11. CeO2-ZrO2 ceramic compounds

    International Nuclear Information System (INIS)

    Melo, F.C.L.; Cairo, C.A.C.; Devezas, T.C.; Nono, M.C.A.

    1988-01-01

    In order to study the mechanical properties of tetragonal polycrystal zirconia stabilized with ceria various powder compositions with different CeO 2 content were made. Modulus of rupture for those compounds was measured. Tetragonal retained phase was determined for samples of CeO 2 -ZrO 2 ceramics with and without superficial mechanical treatment. The experimental results allowed us to evaluate the effects of CeO 2 content and sintering temperature in the mechanical properties and tetragonal transformed phase (t→ m) in ceramics of CeO 2 -ZrO 2 systems. (author) [pt

  12. The curse of the superstar CEO.

    Science.gov (United States)

    Khurana, Rakesh

    2002-09-01

    When struggling companies look for a new chief executive today, the one quality they prize above all others is charisma. But once they've recruited a larger-than-life leader, they often find that their troubles only get worse. Indeed, as the author's new research painfully reveals, the widespread belief in the powers of charismatic CEOs can be problematic. Why? First, Khurana says, there's no conclusive evidence that charismatic leadership affects an organization's performance. And yet--as Kodak's story over the past decade reveals--when a company is faltering, boards feel compelled to oust the incumbent chief executive and bring in a corporate savior. Second, the insistence on finding a charismatic leader, combined with the undefinable nature of charisma, results in selection processes that are overly conservative and even irrational. Boards end up considering only candidates who have already achieved the rank of CEO or president at a high-performing, high-profile company, even if they are not right for the job. Third, charismatic leaders deliberately destabilize organizations. This can result in a more vibrant company, as it did at General Electric during Jack Welch's tenure, but it can also leave a troubled legacy for the organization to overcome, as GE, Ford, and Enron have all found. Faith in a company, a product, or an idea can unleash tremendous innovation and productivity. But the extravagant hopes invested in charismatic CEOs resemble not mature faith but a belief in magic. If we are willing to reconsider our notion of leadership, this age of faith can be followed by an era of faith and reason.

  13. Facile hydrothermal synthesis of CeO2 nanopebbles

    Indian Academy of Sciences (India)

    Administrator

    XRD shows the formation of cubic fluorite CeO2 and the average particle size estimated from the Scherrer formula was found to be 6.69 nm. X-ray absorption spectrum of CeO2 nanopebbles exhibits two .... state.26 In our case, the valence of cerium ions will be mainly 4+ state, because the estimated particle size of.

  14. It's More than Just Talk: Patterns of CEO Impromptu Communication

    Science.gov (United States)

    Grant, Anett D.; Taylor, Amanda

    2015-01-01

    This article investigates whether CEOs actually demonstrate the communication strengths and weaknesses they think they have. Videotaped interviews with CEOs in the initial stage of executive coaching were analyzed to identify categories of communication strength and weakness: delivery, content, audience, and character. Next, the interviews and…

  15. The Influence of CEO Power on Compensation Contract Design

    NARCIS (Netherlands)

    Abernethy, M.; Kuang, Y.; Qin, B.

    2015-01-01

    We investigate whether CEO power influences a firm's decision to change its compensation system in response to regulatory and public pressure. In particular, we assess whether CEO power influences the choice of performance measures as a form of camouflage to minimize the impact of these reforms on

  16. Manajemen Laba Pada Saat Pergantian CEO (Dirut Di Indonesia

    Directory of Open Access Journals (Sweden)

    Priskila Adiasih

    2011-09-01

    Full Text Available This study investigates earnings management of CEO changes in Indonesia. CEO change is classified either as routine or non-routine based on RUPS (General Shareholders Meeting and RUPSLB (Extraordinary General Shareholders Meeting information. The samples are listed company undergoing CEO changes in the Indonesian Stock Market observed from 2000 to 2009. To identify the earnings management practice, modified Jones model of discretionary accruals and Rowchordory’ of real earnings management are employed. The study provides evidence of non-routine incoming CEO undertaking earnings management by minimizing the earnings in the year of CEO change. The evidence shows that reporting minimum earnings is consistent with the notion of new CEO’s engagement in an ‘earnings bath’. However, this study does not support the theory of management compensation contracts during routine CEO changes. In addition, the incumbent CEO in the non-routine changes does not practice earnings management in the final year before the change. Therefore, manipulating earnings is not the argument to a non routine change of CEO.

  17. Dutch space; interview with Arnaud de Jong, CEO

    NARCIS (Netherlands)

    De Jong, A.; Wink, J.; Sabbapathy, R.

    2014-01-01

    Dutch Space, the largest space company in the Netherlands and part of Airbus Defence and Space, appointed a new CEO last year. The Leonardo Times sat down with the CEO Arnaud de Jong for an interview. We discuss his career, developments in Dutch Space, his take on competition in the commercial space

  18. Maximizing Your Grant Development: A Guide for CEOs.

    Science.gov (United States)

    Snyder, Thomas

    1993-01-01

    Since most private and public sources of external funding generally expect increased effort and accountability, Chief Executive Officers (CEOs) at two-year colleges must inform faculty and staff that if they do not expend extra effort their college will not receive significant grants. The CEO must also work with the college's professional…

  19. Three-Dimensional Structure of CeO2 Nanocrystals

    DEFF Research Database (Denmark)

    Tan, Joyce Pei Ying; Tan, Hui Ru; Boothroyd, Chris

    2011-01-01

    truncated octahedral CeO2 particles through a lattice matched interface generated irregular compressed truncated octahedral CeO2 nanoparticles. The formation of this irregular shape is attributed to the lower surface diffusion and slow incorporation of atoms on surfaces by step attachment of the fused...

  20. Working Together in Class

    Directory of Open Access Journals (Sweden)

    Pateşan Marioara

    2017-12-01

    Full Text Available The scores obtained by the military students are very important as a lot of opportunities depend on them: the choice of the branch, selection for different in and off-campus activities, the appointment to the workplace and so on. A qualifier, regardless of its form of effective expression, can make a difference in a given context of issuing a value judgment, in relation to the student's performance assessment. In our research we tried to find out what motives students, what determines them to get actively involved in the tasks they are given and the ways we can improve their participation in classes and assignments. In order to have an educated generation we need to have not only well prepared teachers but ones that are open-minded, flexible and in pace with the methodological novelties that can improve the teaching learning process in class. Along the years we have noticed that in classes where students constituted a cohesive group with an increasing degree of interaction between members, the results were better than in a group that did not appreciate team-work. In this article we want to highlight the fact that a teacher can bring to class the appropriate methods and procedures can contribute decisively to the strengthening of the group cohesion and high scores.

  1. Determinants of CEO Turnover in Publicand Private Firms in Denmark - CEO and Firm Characteristics

    DEFF Research Database (Denmark)

    Sponholtz, Carina

    turnover. Finally, the inverse relationshipbetween firm performance and CEO turnover only exists in LLL firms(larger limited liability firms, both publicly and privately held), whereagency costs are assumed and found to be highest.In this study we are the first to draw on longitudinal matched employer...... only exists in LLL firms(larger limited liability firms, both publicly and privately held), whereagency costs are assumed and found to be highest....

  2. The overconfidence bias and CEO: literature review

    Directory of Open Access Journals (Sweden)

    Tereza Čuláková

    2018-06-01

    Full Text Available This systematic review deals the overconfidence bias. It is a cognitive bias which is described as the tendency of people to overestimate their abilities, prospects and chances of success. For the purpose of the research we chose to examine the influence of overconfidence bias on CEOs’ decision-making and their work in a company. The systematic review followed three main situations revealing CEOs’ overconfidence within a company – dividend policy, innovative processes and hiring new employees. According to the review of the literature, there is no obvious connection between CEOs’ overconfidence and a generous dividend policy. However, as for the innovative processes, it seems that overconfident CEOs are more willing to support a higher number of innovations. In the final situation, the literature does not yet provide decisive guidance on the relationship between CEOs’ overconfidence and the process of managing employees and hiring new ones.

  3. Committee on Earth Observation Satellites (CEOS) Systems Engineering Office (SEO). Ocean Surface Topography (OST) Workshop, Ruedesheim an Rhein, Germany. [CEOS SEO Status Report

    Science.gov (United States)

    Killough, Brian D., Jr.

    2008-01-01

    The CEOS Systems Engineering Office will present a 2007 status report of the CEOS constellation process, present a new systems engineering framework, and analysis results from the GEO Societal Benefit Area (SBA) assessment and the OST constellation requirements assessment.

  4. CEOs as risk takers--from vision to reality.

    Science.gov (United States)

    1990-11-20

    Health care management today is inherently risky. And because of the environment of high CEO turnover and bottom-line responsibility in which executives work, some CEOs become enmeshed in a crisis-management mode on a day-to-day basis. But there are some administrators with broader visions of what their institutions should be and what they should achieve, and who are willing to risk their reputations--and more--to bring those visions to reality. From a Massachusetts' hospital system's downsizing to a California medical center's pioneering advances in technology to a Nebraska hospital system's new marketing approach to an Ohio CEO's creativity mandate, here's how six CEOs in very different situations took risks.

  5. CEO Interests and Concerns in Second Wave ERP

    DEFF Research Database (Denmark)

    Simonsen, Martin Lyngaa; Nielsen, Esben Toftdahl; Kræmmergaard, Pernille

    2006-01-01

    This paper is the product of a study of what top management find interesting and what is of concern to them in relation to the Enterprise Resource Planning (ERP) systems in the second wave of ERP. Very little empirical research exists on the subject of the interests and concerns of CEOs in relation...... to a company's ERP System. However research into information system literature indicates that CEOs are valued as key players in the management of IT to secure that the IT strategy is aligned with the business strategy. Based on the fact that very little prior research exists on the CEOs' interests and concerns...... in relation to the ERP system in the second wave, we employed an interpretive explorative case study with a grounded approach carried out through open interviews with CEOs. The research was conducted in three mid-size Danish production companies all of which have an ERP system. The contribution of this paper...

  6. Committee on Earth Observation Satellites (CEOS) International Directory Portal

    Data.gov (United States)

    National Aeronautics and Space Administration — The CEOS IDN is an international effort developed to assist researchers in locating information on available datasets and services. The directory is sponsored as a...

  7. A CEO roundtable on making mergers succeed.

    Science.gov (United States)

    Mandl, A; Bohnett, D; Liddy, E; Komansky, D; Kozlowski, D; Leschly, J; Gupta, R; McDonald, M; Avery, B; Moore, N; Krekel, T

    2000-01-01

    The announcement in January of the merger between America Online and Time Warner marked the convergence of the two most important business trends of the last five years--the rise of the Internet and the resurgence of mergers and acquisitions. M&A activity is at a fever pitch, spurred in large part by the breathtaking influx of capital into the Internet space. And all signs indicate the trend will only accelerate. Against this background, an impressive group of experienced deal makers came together to share their experiences of what makes mergers work. They were assembled in Scottsdale, Arizona, under the auspices of the M&A Group, a professional society formed in 1999 for CEOs interested in M&A as a business strategy. Participants included top executives from Internet start-ups like Teligent; venture capital firms like Baroda Ventures; financial institutions like Merrill Lynch and PricewaterhouseCoopers; and major corporations like Allstate, Tyco International, SmithKline Beecham, Rohm and Haas, VF, Crown Cork & Seal, and Hughes Space and Communications. The spirited and surprisingly frank discussion cut a wide swath, considering issues such as whether most mergers fail to pan out as well as expected, how to increase the odds of success, the nuts and bolts of the integration process, the trade-offs between acquiring a company and growing from within, the importance of cultural issues, and why anyone would want to be on the board of a merged company.

  8. The CEO hits the road (and other sales tales).

    Science.gov (United States)

    Mackay, H B

    1990-01-01

    Kenneth Macke, CEO of Dayton-Hudson, the soft goods and discount store chain, often spends weekends prowling his own and competitors' stores, observing. Edwin Artzt, CEO of Procter & Gamble, once interrupted a global marketing jaunt to work with a division on its promotion plans. These are CEOs in the trenches, a place where they ought to spend a certain amount of their time so that they can learn how the business is going. "A desk is a dangerous place from which to view the world," says John le Carré, as quoted approvingly by the author. Mackay asserts that time spent on the road with the sales force is especially valuable. You will learn: Whether all the sales team knows its prospects and sets reasonable expectations. How much the salespeople know about the product, particularly in ways that differentiate it from the competition. Whether the sellers keep abreast of changes in customers' businesses. If the salespeople feel they have a stake in the business. As a rookie envelope salesman, Mackay was taken in tow by a veteran and shown the value of learning the competition's local customer base intimately. Later, as the CEO with a junior salesperson in tow, he demonstrated the value of learning not only the competition's moves but also the customers'. To close sales, salespeople and the CEO have to look over their customers' shoulders as well as their competitors'.

  9. Firm performance: The role of CEOs' emotional and cognitive characteristics

    Directory of Open Access Journals (Sweden)

    Kleanthis K. Katsaros

    2015-08-01

    Full Text Available The paper examines the relationships between CEOs’ personal traits, emotions, attitudes and tolerance of ambiguity; and subsequently, the influence of CEOs’ ambiguity tolerance in firms' performance. Design/methodology/approach – Survey data were collected from 256 ICT firms established in Greece. Their CEOs completed questionnaires examining TOA, personal traits, emotions and attitudes in the workplace. Principal components analysis and ordinary least-squares regressions were used to explore the hypotheses of the paper. Findings – Three factors characterize CEOs' emotions, namely pleasure, dominance and arousal; two factors their involvement, namely importance and interest; and, respectively, one their emotional intelligence namely, empathy/handling relationships. Further, locus of control; importance; arousal; empathy/handling relationships and interest affect decisively CEOs' tolerance of ambiguity, which in turn, seems to influence positively firms' performance. Research limitations/implications – Further research is required in Greek ICT industry regarding the influence of CEOs' emotional and cognitive attributes in organizations' financial performance. Likewise, this research should be expanded to other industries. Originality/value – The originality of this study lies in the finding that emotional and cognitive characteristics affect CEOs' TOA, which, in turn, influences significantly firms' performance. Another significant contributing factor is that the study is carried out in Greece, where few studies have been conducted in this area.

  10. 2013 CEO leadership forum, leading the 21st century DOT : a summary report.

    Science.gov (United States)

    2013-04-01

    This report summarizes the 2013 CEO Leadership Forum : for state departments of transportation (DOTs). Over : three days, transportation leaders from across the nation : explored a range of issues and developed action plans to : support CEOs and thei...

  11. New Firm Performance and the Replacement of Founder-CEOs

    DEFF Research Database (Denmark)

    Chen, Jing; Thompson, Peter

    2015-01-01

    We study the causes and consequences of the replacement of founder-CEOs in a sample of 4,172 Danish start-ups. We propose that founder-CEO replacement is driven in part by mismatches between business quality and founder ability. Our framework suggests that replacements are more likely among...... the worst- and best-performing firms, with low (high)-ability founders replaced by manager with higher (lower) ability. Replacement is not unambiguously associated with better subsequent performance. Firms that replaced the founder were much more likely to fail, but the surviving firms among them grew...

  12. Do transformational CEOs always make the difference? The role of TMT feedback seeking behavior

    NARCIS (Netherlands)

    Stoker, Janka I.; Grutterink, Hanneke; Kolk, Nanja J.

    In the present paper, we raise the question whether CEO transformational leadership invariably makes a difference for team performance and change effectiveness. Since in general, CEOs are surrounded by a team of highly influential top managers, we argue that the effectiveness of CEO transformational

  13. Novel nanostructured CeO2 as efficient catalyst for energy and ...

    Indian Academy of Sciences (India)

    CeO2 and CeO2 based hetero-nanocomposites for their suitability to important catalytic and energy-related applications. Keywords. CeO2; morphology; catalysis; soot oxidation; CO oxidation; ethanol electro-oxidation. 1. Introduction .... glycol)-poly(propylene glycol)-poly(ethylene glycol). (P123, Sigma-Aldrich) with a ...

  14. Optical properties of CeO2 thin films

    Indian Academy of Sciences (India)

    TECS

    The values of absorption coefficient, extinction coefficient, refractive index, dielectric constant, phase angle and loss angle have been calculated from the optical measurements. The X-ray diffraction of the film showed that the film is crystalline in nature. The crystallite size of CeO2 films have been evaluated and found to be.

  15. Does CEOs' familiarity with business segments affect their divestment decisions?

    NARCIS (Netherlands)

    J. Ang (James); A. de Jong (Abe); A.M. van der Poel (Marieke)

    2012-01-01

    markdownabstract__Abstract__ We examine the impact of familiarity with business segments on CEOs’ divestment decisions. We find CEOs to be less likely to divest assets from familiar than from non-familiar segments. We attribute this effect to CEOs’ comparative information advantage relative to

  16. The relationship between South African CEO compensation and ...

    African Journals Online (AJOL)

    This exploratory study is based on a statistical data analysis to determine whether a long-term correlation is present between South African CEO compensation and company performance in the banking sector. The detailed analysis, using a seven-year time period, is performed at individual company level as well as at ...

  17. CEO Interests and Concerns in Second Wave ERP

    DEFF Research Database (Denmark)

    Simonsen, Martin Lyngaa; Nielsen, Esben Toftdahl; Kræmmergaard, Pernille

    2006-01-01

    This paper is the product of a study of what top management find interesting and what is of concern to them in relation to the Enterprise Resource Planning (ERP) systems in the second wave of ERP. Very little empirical research exists on the subject of the interests and concerns of CEOs in relation...

  18. IZINDABA: A timely appointment - SAMA\\'s new CEO | Bateman ...

    African Journals Online (AJOL)

    IZINDABA: A timely appointment - SAMA\\'s new CEO. Chris Bateman. Abstract. No abstract. South African Medical Journal Vol. 95 (8) 2005: 554-556. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. HOW TO USE AJOL.

  19. The institutional determinants of CEO compensation: An international empirical evidence

    Directory of Open Access Journals (Sweden)

    Fakhfakh, H.

    2011-01-01

    Full Text Available Corporate governance literature suggests that the relationship between CEO effort and outcomes such as firm performance is highly uncertain due to the influence of numerous organizational and environmental contingencies that are outside CEOs’ control. The major focus of this study is to determine whether institutional factors explain cross-sectional differences in CEO pay structure and sensitivity to performance and luck. Thus, we address three ultimate questions; Are CEOs rewarded for luck? Does institutional features matter for CEO pay for luck? How do systematic incentive effect is sensitive to luck’s nature? Ordinary Least Squares (OLS and Instrumental Variables (I.V. estimations based on a sample of 300 publicly traded firms covering four countries from the Anglo-American and Euro-Continental corporate governance models between 2004 and 2008 show that the answers to the two first questions are a surrounding yes. Robustness check tests relying to the third question provide evidence that pay for luck is asymmetric. That is, executives are rewarded for good luck but they are safe of bad luck.

  20. Optical properties of CeO2 thin films

    Indian Academy of Sciences (India)

    TECS

    increase with increase in thickness. The values of absorp- tion coefficient, extinction coefficient, refractive index, dielectric constant, phase angle and loss angle were found to be in conformity with previous works. From the X-ray diffraction studies it is found that CeO2 thin film has crys- talline structure and a smaller crystallite ...

  1. The relationship between South African CEO compensation and ...

    African Journals Online (AJOL)

    company performance, namely market performance (share price) and accounting performance (return on equity, ..... Given the recent re-pricing of certain CEOs' basic packages, it is important to consider total compensation to ..... mmdcclxxivSTI target measures (as % of guaranteed pay) mmdcclxxv182% mmdcclxxvi162%.

  2. Consistency in behavior of the CEO regarding corporate social responsibility

    NARCIS (Netherlands)

    Elving, W.J.L.; Kartal, D.

    2012-01-01

    Purpose - When corporations adopt a corporate social responsibility (CSR) program and use and name it in their external communications, their members should act in line with CSR. The purpose of this paper is to present an experiment in which the consistent or inconsistent behavior of a CEO was

  3. Facile preparation of self-healing superhydrophobic CeO2 surface by electrochemical processes

    Science.gov (United States)

    Nakayama, Katsutoshi; Hiraga, Takuya; Zhu, Chunyu; Tsuji, Etsushi; Aoki, Yoshitaka; Habazaki, Hiroki

    2017-11-01

    Herein we report simple electrochemical processes to fabricate a self-healing superhydrophobic CeO2 coating on Type 304 stainless steel. The CeO2 surface anodically deposited on flat stainless steel surface is hydrophilic, although high temperature-sintered and sputter-deposited CeO2 surface was reported to be hydrophobic. The anodically deposited hydrophilic CeO2 surface is transformed to hydrophobic during air exposure. Specific accumulation of contaminant hydrocarbon on the CeO2 surface is responsible for the transformation to hydrophobic state. The deposition of CeO2 on hierarchically rough stainless steel surface produces superhydrophobic CeO2 surface, which also shows self-healing ability; the surface changes to superhydrophilic after oxygen plasma treatment but superhydrophobic state is recovered repeatedly by air exposure. This work provides a facile method for preparing a self-healing superhydrophobic surface using practical electrochemical processes.

  4. STK Integrated Message Production List Editor (SIMPLE) for CEO Operations

    Science.gov (United States)

    Trenchard, Mike; Heydorn, James

    2014-01-01

    Late in fiscal year 2011, the Crew Earth Observations (CEO) team was tasked to upgrade and replace its mission planning and mission operations software systems, which were developed in the Space Shuttle era of the 1980s and 1990s. The impetuses for this change were the planned transition of all workstations to the Windows 7 64-bit operating system and the desire for more efficient and effective use of Satellite Tool Kit (STK) software required for reliable International Space Station (ISS) Earth location tracking. An additional requirement of this new system was the use of the same SQL database of CEO science sites from the SMMS, which was also being developed. STK Integrated Message Production List Editor (SIMPLE) is the essential, all-in-one tool now used by CEO staff to perform daily ISS mission planning to meet its requirement to acquire astronaut photography of specific sites on Earth. The sites are part of a managed, long-term database that has been defined and developed for scientific, educational, and public interest. SIMPLE's end product is a set of basic time and location data computed for an operator-selected set of targets that the ISS crew will be asked to photograph (photography is typically planned 12 to 36 hours out). The CEO operator uses SIMPLE to (a) specify a payload operations planning period; (b) acquire and validate the best available ephemeris data (vectors) for the ISS during the planning period; (c) ingest and display mission-specific site information from the CEO database; (d) identify and display potential current dynamic event targets as map features; (e) compute and display time and location information for each target; (f) screen and select targets based on known crew availability constraints, obliquity constraints, and real-time evaluated constraints to target visibility due to illumination (sun elevation) and atmospheric conditions (weather); and finally (g) incorporate basic, computed time and location information for each selected

  5. Big-five personality as a moderating variable in the relationship of CEO's perception and the compensation received toward CEO's desire to leave the company voluntarily

    Directory of Open Access Journals (Sweden)

    Lindrianasari Lindrianasari

    2015-08-01

    Full Text Available The study aims to obtain empirical evidence for the effect of personality on the impact of compensation received by CEO in Indonesia toward CEO voluntary turnover. This study uses two sources of data, primary and secondary. The research population consists of all president directors (as a proxy of the CEOs of companies listed on the Indonesia Stock Exchange. The data on CEO turnover were collected manually by tracing the names of the Director stated on the company's annual report. To determine whether CEO turnover was involuntary or coercive, this research examined the growth of the company in which the CEO turnover occurred after the CEO had served a minimum of three consecutive years. Test result on the relationship between com-pensation and turnover indicates that compensation is not strong enough to explain voluntary CEO turnover. Only the control variables included in the model (earnings, returns and ROA can explain statistically the relationship between compensation and turnover. The result of these two tests (hypothesis one and two indicates that com-pensation is not strong enough to explain voluntary turnover.

  6. A Conversation with Howard Schultz CEO of Starbucks

    Directory of Open Access Journals (Sweden)

    Christopher Muller

    2014-04-01

    Full Text Available At the 12th annual European Food Service Summit in Zurich, Switzerland in September 2011, Professor Christopher Muller sat down with Howard Schultz, the CEO of Starbucks to discuss a wide range of topics. Their discussion touched on best management and business practices and the techniques that Schultz used to bring Starbucks back from the brink of bankruptcy to the international coffee corporation it is today.

  7. Stock Market Reaction to CEO Appointment – Preliminary Results

    Directory of Open Access Journals (Sweden)

    Katarzyna Byrka-Kita

    2017-06-01

    Full Text Available Purpose: The aim of this paper is to examine shareholders’ reaction to the decision of the supervisory board to appoint a CEO in companies listed on the Warsaw Stock Exchange. Methodology: An event study and the mean-adjusted model were applied. The abnormal returns were measured as the CAAR in the entire (-60, + 60 window and selected sub-windows. Findings: The obtained values of abnormal returns indicate the shareholder’s negative reaction. Throughout the observation window, they oscillate slightly below zero, and in the window (0, +20 they are negative at -1.566%. Irrespective of the observation window, negative abnormal returns were obtained for over half of the observation (52–57%. Therefore, preliminary results indicate the predominance of the information effect over the real one. The decrease in market value as a result of the event may result from an increase in investors’ uncertainty as to the effects of changes in strategy and skills of the new CEO. Originality: The research is a unique one. To date, no one has carried out research into shareholders’ reaction to a CEO appointment in either the Polish or Central and Eastern European capital markets. They primarily bring the value of cognition of shareholders’ behaviour in the analysed event, which is reflected in share prices. They extend the literature on the signalization instruments, i.e. the activities that boards can undertake due to the new information transmitted to the capital market participants and stakeholders. The market reaction to a CEO appointment will without a doubt interest investors; the institutions responsible for supervision (which in the case of Poland is the Financial Oversight Commission and the legislator in charge of regulations that prevent insider trading while promoting corporate disclosure transparency.

  8. F-centre luminescence in nanocrystalline CeO2

    International Nuclear Information System (INIS)

    Aškrabić, S; Dohčević-Mitrović, Z D; Araújo, V D; Ionita, G; De Lima, M M Jr; Cantarero, A

    2013-01-01

    Nanocrystalline CeO 2 powders were synthesized by two cost-effective methods: the self-propagating room temperature (SPRT) method and the precipitation method. Differently prepared samples exhibited different temperature-dependent photoluminescence (PL) in the ultraviolet and visible regions. The PL signals originated from different kinds of oxygen-deficient defect centres with or without trapped electrons (F 0 , F + or F ++ centres). The temperature-dependent PL spectra were measured using different excitation lines, below (457, 488 and 514 nm) or comparable (325 nm) to the ceria optical band gap energy, in order to investigate the positions of intragap localized defect states. Evidence for the presence of F + centres was supported by the signals observed in electron paramagnetic resonance (EPR) measurements. Based on PL and EPR measurements it was shown that F + centres dominate in the CeO 2 sample synthesized by the SPRT method, whereas F 0 centres are the major defects in the CeO 2 sample synthesized by the precipitation method. The luminescence from F ++ states, as shallow trap states, was registered in both samples. Energy level positions of these defect states in the ceria band gap were proposed. (paper)

  9. F-centre luminescence in nanocrystalline CeO2

    Science.gov (United States)

    Aškrabić, S.; Dohčević-Mitrović, Z. D.; Araújo, V. D.; Ionita, G.; de Lima, M. M., Jr.; Cantarero, A.

    2013-12-01

    Nanocrystalline CeO2 powders were synthesized by two cost-effective methods: the self-propagating room temperature (SPRT) method and the precipitation method. Differently prepared samples exhibited different temperature-dependent photoluminescence (PL) in the ultraviolet and visible regions. The PL signals originated from different kinds of oxygen-deficient defect centres with or without trapped electrons (F0, F+ or F++ centres). The temperature-dependent PL spectra were measured using different excitation lines, below (457, 488 and 514 nm) or comparable (325 nm) to the ceria optical band gap energy, in order to investigate the positions of intragap localized defect states. Evidence for the presence of F+ centres was supported by the signals observed in electron paramagnetic resonance (EPR) measurements. Based on PL and EPR measurements it was shown that F+ centres dominate in the CeO2 sample synthesized by the SPRT method, whereas F0 centres are the major defects in the CeO2 sample synthesized by the precipitation method. The luminescence from F++ states, as shallow trap states, was registered in both samples. Energy level positions of these defect states in the ceria band gap were proposed.

  10. IT Decision Making in German Hospitals - Do CEOs Open the Black Box?

    Science.gov (United States)

    Thye, Johannes; Hübner, Ursula; Hüsers, Jens; Babitsch, Birgit

    2017-01-01

    Health IT and communication systems are indispensable in German hospitals for clinical as well as administrative process support. However, IT is often regarded as a "black box" for hospital CEOs. Thus, the question arises how can CEOs decide if they do not know what is in the box? In order to answer this question, half-structured interviews with 14 German hospital CEOs were conducted. They revealed three principle decision processes: the supported decision, the joint decision and the corporate level decision. In all cases, the hospital CEO and the CIO interacted to reach the final decision, most strongly in the joint decision mode and least strongly in the corporate decision mode. Only the joint decision mode definitely forced the CEO to open the "black box" of IT. In the era of digitalisation, however, CEOs must develop better competencies to decide over complex matters.

  11. Professional Elites in "Classes" Societies

    NARCIS (Netherlands)

    S.J. Magala (Slawomir)

    2003-01-01

    textabstractModern European identity has been forged in class struggles between the French revolution and fall of the Berlin Wall, which fell twice. Once, with the rest of the city in May 1945, when a national socialist alternative to a modernizing mix of parliamentary democracy and market economy

  12. Civility in Classes and Sports

    Science.gov (United States)

    Lumpkin, Angela

    2010-01-01

    Civility is a polite or courteous act, expression, or standard of conduct, including the display of respect and tolerance to everyone. Teaching and modeling civility in classes and with sport teams is essential so students and athletes can learn the importance of and demonstrate civility in their interactions with others. Teachers and coaches…

  13. Modelling of volumetric properties of binary and ternary mixtures by CEOS, CEOS/GE and empirical models

    Directory of Open Access Journals (Sweden)

    BOJAN D. DJORDJEVIC

    2007-12-01

    Full Text Available Although many cubic equations of state coupled with van der Waals-one fluid mixing rules including temperature dependent interaction parameters are sufficient for representing phase equilibria and excess properties (excess molar enthalpy HE, excess molar volume VE, etc., difficulties appear in the correlation and prediction of thermodynamic properties of complex mixtures at various temperature and pressure ranges. Great progress has been made by a new approach based on CEOS/GE models. This paper reviews the last six-year of progress achieved in modelling of the volumetric properties for complex binary and ternary systems of non-electrolytes by the CEOS and CEOS/GE approaches. In addition, the vdW1 and TCBT models were used to estimate the excess molar volume VE of ternary systems methanol + chloroform + benzene and 1-propanol + chloroform + benzene, as well as the corresponding binaries methanol + chloroform, chloroform + benzene, 1-propanol + chloroform and 1-propanol + benzene at 288.15–313.15 K and atmospheric pressure. Also, prediction of VE for both ternaries by empirical models (Radojković, Kohler, Jackob–Fitzner, Colinet, Tsao–Smith, Toop, Scatchard, Rastogi was performed.

  14. Hanging Together, Together Hung? Career Implications of Interpersonal Ties Between CEOs and Top Managers

    Directory of Open Access Journals (Sweden)

    Stefan Hilger

    2013-05-01

    Full Text Available Is it good or bad for senior executives to have strong interpersonal ties to the CEO? We argue that a strong relationship with the CEO raises the likelihood that a top manager stays in office or makes an upward career move when the CEO leaves office voluntarily. At the same time, such interpersonal ties also reinforce the negative spillover effects of a dismissal of the CEO on the career prospects of the manager concerned. Our empirical analysis lends support to both arguments. We contribute to managerial succession research by underlining the ambivalence of interpersonal ties within top management teams.

  15. Photocatalytic degradation of dye using CeO2/SCB composite catalysts

    Science.gov (United States)

    Channei, Duangdao; Nakaruk, Auppatham; Phanichphant, Sukon

    2017-08-01

    The main task of the present work is to enhance the photocatalytic degradation efficiency of methylene blue (MB) by using CeO2/sugarcane bagasse (SCB) composite catalysts. Homogeneous precipitation method was used to synthesis CeO2-SCB composite catalysts by adding SCB powder to precursor solution of Ce base-metal. The structural analytical data indicated the pure cubic fluorite structure of CeO2. Morphological images revealed the coating of CeO2 layer on high surface area of SCB core-shell. The chemical analysis presented spectrum of the Ce 3d in CeO2/SCB sample existed in the form of the Ce3 + and Ce4 + mixed- valence states. Optical spectra showed the shift of absorption edge towards longer visible region upon supporting CeO2 with SCB. The main chemical composition of the SCB was K, Ca, and Si. Furthermore, recombination of the photogenerated electrons and holes was identified by photoluminescence techniques (PL), the data suggested inhibition of electron-hole pairs recombination by the cations from SCB loaded in CeO2/SCB composite. Photocatalytic activity of CeO2/SCB catalyst was investigated via the degradation of MB under UV-A irradiation. Experimental kinetic data followed the pseudo-first order model. CeO2 supported with SCB adsorbent had higher photocatalytic activity in dye wastewater treatment compared to the pure CeO2. The proposed mechanism explaining the high photocatalytic efficiency of CeO2/SCB was associated with high surface properties and the suppression of recombination of the photogenerated electron-hole pairs by the SCB adsorbent.

  16. Fast humidity sensors based on CeO2 nanowires

    International Nuclear Information System (INIS)

    Fu, X Q; Wang, C; Yu, H C; Wang, Y G; Wang, T H

    2007-01-01

    Fast humidity sensors are reported that are based on CeO 2 nanowires synthesized by a hydrothermal method. Both the response and recovery time are about 3 s, and are independent of the humidity. The sensitivity increases gradually as the humidity increases, and is up to 85 at 97% RH. The resistance decreases exponentially with increasing humidity, implying ion-type conductivity as the humidity sensing mechanism. A model based on the morphology and surface energy of the nanowires is given to explain these results further. Our experimental results indicate a pathway to improving the performance of humidity sensors

  17. The Contrabassist and the CEO: Moral Judgment and Collective Identity

    Directory of Open Access Journals (Sweden)

    Alessandro Pinzani

    2003-01-01

    Full Text Available How much is a moral judgment on a single act influenced by circumstances which have little to do with the nature of the act itself? How much have certain moral judgments to do with the common history and shared experience of a certain group of individuals? Using two cases taken from life (a German musician and a German CEO behaving both in a morally wrong way but with very different consequences from the point of view of moral judgement and with very different reactions from the German public, the article tries to give an answer to these questions, touching issues like: guilt, moral responsibility, collective responsibility, and collective identity.

  18. 76 FR 12337 - Request for Applicants for Appointment to the United States-Brazil CEO Forum

    Science.gov (United States)

    2011-03-07

    ... International Trade Administration Request for Applicants for Appointment to the United States- Brazil CEO Forum... 2007, the Governments of the United States and Brazil established the U.S.-Brazil CEO Forum. This... of the Forum. The current U.S. Section term will expire on June 11, 2011. DATES: Applications should...

  19. 78 FR 32239 - Request for Applicants for Appointment to the United States-Brazil CEO Forum

    Science.gov (United States)

    2013-05-29

    ... International Trade Administration Request for Applicants for Appointment to the United States- Brazil CEO Forum... 2007, the Governments of the United States and Brazil established the U.S.-Brazil CEO Forum. This... representatives to the U.S. Section of the Forum. The term of the current representatives to the U.S. Section will...

  20. CEO Business Education and Firm Financial Performance: A Case for Humility Rather than Hubris

    Science.gov (United States)

    Lindorff, Margaret; Jonson, Elizabeth Prior

    2013-01-01

    Purpose: The purpose of this paper is to examine the relationship between CEO business education and firm financial performance. Design/methodology/approach: An analysis of the relationship between three-year and five-year shareholder return as measured by dividend and change in share price and CEO educational qualification was performed.…

  1. The Lived Experiences of Asian Americans Who Became Chief Executive Officers (CEOs) of California Community Colleges

    Science.gov (United States)

    Ramones, Eric

    2017-01-01

    The purpose of this phenomenological study was to explore the lived experiences of Asian Americans who became chief executive officers (CEOs) of a California Community College District. This study discussed the experiences, the influence of Asian culture, the perception of Asian Americans, and the challenges encountered by Asian American CEOs. To…

  2. DETERMINANTS OF INTERNAL VS. EXTERNAL CEO SUCCESSIONS IN MALAYSIAN PUBLIC LISTED COMPANIES

    Directory of Open Access Journals (Sweden)

    Rokiah Ishak

    2012-01-01

    Full Text Available Following a CEO turnover, a company may select an internal or external successor. The objective of this study is to determine if firm performance, board attributes, ownership structure and incumbent power influence the decision of whether to elect an internal or external candidate. Results from logistic regression analysis on 145 succession events over a four-year period (2002 to 2005 indicate that firms which are controlled by blockholders tend to select an outsider as the successor. Further, firms that are controlled by family members and position their former CEOs within the firms are more likely to select insiders as successors. However, firm performance, board composition, CEO duality and turnover type do not affect the selection choice. This study implies that poor firm performance does not necessarily lead to outside CEO selection choice. Further, boards of Malaysian PLCs are not effective in choosing outsiders as successors as both board composition and CEO duality do not necessarily select outsiders to become new CEOs. Another implication of this study is that former CEOs who continue their directorship in the same companies do have some power in naming new CEOs as the former tend to select insiders as successors.

  3. Redox enzyme-mimicking activities of CeO2nanostructures: Intrinsic influence of exposed facets.

    Science.gov (United States)

    Yang, Yushi; Mao, Zhou; Huang, Wenjie; Liu, Lihua; Li, Junli; Li, Jialiang; Wu, Qingzhi

    2016-10-17

    CeO 2 nanoparticles (NPs) have been well demonstrated as an antioxidant in protecting against oxidative stress-induced cellular damages and a potential therapeutic agent for various diseases thanks to their redox enzyme-mimicking activities. The Ce 3+ /Ce 4+ ratio and oxygen vacancies on the surface have been considered as the major originations responsible for the redox enzyme-mimicking activities of CeO 2 NPs. Herein, CeO 2 nanostructures (nanocubes and nanorods) exposed different facets were synthesized via a facile hydrothermal method. The characterizations by X-ray photoelectron spectroscopy, Raman spectroscopy, and UV-Vis spectroscopy show that the Ce 3+ /Ce 4+ ratio and oxygen vacancy content on the surfaces of as-synthesized CeO 2 nanostructures are nearly at the same levels. Meanwhile, the enzymatic activity measurements indicate that the redox enzyme-mimicking activities of as-synthesized CeO 2 nanostructures are greatly dependent on their exposed facets. CeO 2 nanocubes with exposed {100} facets exhibit a higher peroxidase but lower superoxide dismutase activity than those of the CeO 2 nanorods with exposed {110} facets. Our results provide new insights into the redox enzyme-mimicking activities of CeO 2 nanostructures, as well as the design and synthesis of inorganic nanomaterials-based artificial enzymes.

  4. Novel nanostructured CeO 2 as efficient catalyst for energy and ...

    Indian Academy of Sciences (India)

    We report here versatile methods to engineer the microstructure and understand the fundamental physicochemical properties of CeO2 to improve its catalytic viability for practical applications. In this context, different morphologies of CeO2 are synthesized using tailored homogeneous precipitation methods and ...

  5. CEO Ideational Facilitation Leadership and Team Creativity: The Mediating Role of Knowledge Sharing

    Science.gov (United States)

    Carmeli, Abraham; Paulus, Paul B.

    2015-01-01

    The development of new ventures is often based on collective creative efforts. We conceptualize team creativity as a process of looking for and exploring new solutions and examine whether and how CEO leadership fosters creativity in top management teams (TMT). Data collected from senior executive teams indicate that CEO ideational facilitation…

  6. Heteroaggregation, transformation and fate of CeO2 nanoparticles in wastewater treatment

    International Nuclear Information System (INIS)

    Barton, Lauren E.; Auffan, Melanie; Olivi, Luca; Bottero, Jean-Yves; Wiesner, Mark R.

    2015-01-01

    Wastewater Treatment Plants (WWTPs) are a key pathway by which nanoparticles (NPs) enter the environment following release from NP-enabled products. This work considers the fate and exposure of CeO 2 NPs in WWTPs in a two-step process of heteroaggregation with bacteria followed by the subsequent reduction of Ce(IV) to Ce(III). Measurements of NP association with solids in sludge were combined with experimental estimates of reduction rate constants for CeO 2 NPs in Monte Carlo simulations to predict the concentrations and speciation of Ce in WWTP effluents and biosolids. Experiments indicated preferential accumulation of CeO 2 NPs in biosolids where reductive transformation would occur. Surface functionalization was observed to impact both the distribution coefficient and the rates of transformation. The relative affinity of CeO 2 NPs for bacterial suspensions in sludge appears to explain differences in the observed rates of Ce reduction for the two types of CeO 2 NPs studied. - Highlights: • We combine experimental and computational methods to track CeO 2 NPs through WWTPs. • We investigate the importance of environmental transformations on NP exposure. • We estimate the concentrations of CeO 2 NPs and reductive transformation byproducts. - CeO 2 nanoparticles that are released to the waste stream will preferentially associate with the solid phase (∼96%), where they will undergo significant transformation (∼50%)

  7. Synthesis of Mn-doped CeO2 nanorods and their application as ...

    Indian Academy of Sciences (India)

    as humidity sensors. C H HU, C H XIA. ∗. , F WANG, M ZHOU, P F YIN and X Y HAN. Science College of Chongqing Jiaotong University, Chongqing 400074, PR China. MS received 10 October 2010; revised 21 December 2010. Abstract. Mn-doped CeO2 nanorods have been prepared from CeO2 particles through a facile ...

  8. Share Price Reactions to CEO Resignations and Large Shareholder Monitoring in Listed French Companies

    NARCIS (Netherlands)

    Dherment-Ferere, I.; Renneboog, L.D.R.

    2000-01-01

    This study has analysed the share price reactions to changes in top management.A distinction was made among different types of CEO turnover: forced resignation, voluntary departures and age-related retirements.The announcement of a forced CEO resignation is hailed favourably by the market with a

  9. Increased self-efficacy for vegetable preparation following an online, skill-based intervention and in-class tasting experience as a part of a general education college nutrition course.

    Science.gov (United States)

    Brown, Katie N; Wengreen, Heidi J; Vitale, Tamara S; Anderson, Janet B

    2011-01-01

    Assess the effectiveness of the integration of vegetable demonstration videos and tasting experiences into a college nutrition course to influence students' readiness to change vegetable intake, self-efficacy for vegetable preparation, and usual vegetable intake. Quasiexperimental, preintervention-postintervention comparisons. College nutrition course. Of the 376 students enrolled in the course, 186 completed the online assessments (145 female, 41 male; mean age, 20 years). Participants viewed online vegetable preparation videos and participated in vegetable tasting experiences that featured four target vegetables, one vegetable each month for 4 months. Preintervention and postintervention online surveys determined usual vegetable intake, readiness to change vegetable consumption, and self-efficacy of vegetable preparation. Chi-square distribution and paired sample t-tests were used to examine differences preintervention and postintervention. Stage of readiness to change vegetable intake shifted from contemplation toward preparation (p Online vegetable demonstration videos may be an effective and cost-efficient intervention for increasing self-efficacy of vegetable preparation and readiness to increase vegetable consumption among college students. More research is needed to determine long-term effects on vegetable consumption.

  10. Gender Differences in Hospital CEO Compensation: A National Investigation of Not-for-Profit Hospitals.

    Science.gov (United States)

    Song, Paula H; Lee, Shoou-Yih Daniel; Toth, Matthew; Singh, Simone R; Young, Gary J

    2018-01-01

    Gender pay equity is a desirable social value and an important strategy to fill every organizational stratum with gender-diverse talent to fulfill an organization's goals and mission. This study used national, large-sample data to examine gender difference in CEO compensation among not-for-profit hospitals. Results showed the average unadjusted annual compensation for female CEOs in 2009 was $425,085 compared with $581,121 for male CEOs. With few exceptions, the difference existed across all types of not-for-profit hospitals. After controlling for hospital- and area-level characteristics, female CEOs of not-for-profit hospitals earned 22.6% less than male CEOs of not-for-profit hospitals. This translates into an earnings differential of $132,652 associated with gender. Explanations and implications of the results are discussed.

  11. Preparation of nanosized yttrium doped CeO2 catalyst used for photocatalytic application

    Directory of Open Access Journals (Sweden)

    A. Akbari-Fakhrabadi

    2015-09-01

    Full Text Available In the present work, the pure CeO2 and yttrium doped CeO2 nanopowders were synthesized by the nitrate-fuel self-sustaining combustion method and calcined at 700 °C for 2 h. X-ray diffraction (XRD and high resolution electron transmission microscopy (HRTEM results demonstrated a cubic fluorite with high purity and the crystallite sizes less than 20 nm calculated from Scherrer’s formula. The BET specific surface area of yttrium doped CeO2 samples showed high values than those of pure CeO2. The photocatalytic activity of yttrium doped CeO2 showed high degradation of Rhodamine B solution under visible light illumination.

  12. Oral health in Brazil - Part II: Dental Specialty Centers (CEOs

    Directory of Open Access Journals (Sweden)

    Vinícius Pedrazzi

    2008-08-01

    Full Text Available The concepts of health promotion, self-care and community participation emerged during the 1970s and, since then, their application has grown rapidly in the developed world, showing evidence of effectiveness. In spite of this, a major part of the population in the developing countries still has no access to specialized dental care such as endodontic treatment, dental care for patients with special needs, minor oral surgery, periodontal treatment and oral diagnosis. This review focuses on a program of the Brazilian Federal Government named CEOs (Dental Specialty Centers, which is an attempt to solve the dental care deficit of a population that is suffering from oral diseases and whose oral health care needs have not been addressed by the regular programs offered by the SUS (Unified National Health System. Literature published from 2000 to the present day, using electronic searches by Medline, Scielo, Google and hand-searching was considered. The descriptors used were Brazil, Oral health, Health policy, Health programs, and Dental Specialty Centers. There are currently 640 CEOs in Brazil, distributed in 545 municipal districts, carrying out dental procedures with major complexity. Based on this data, it was possible to conclude that public actions on oral health must involve both preventive and curative procedures aiming to minimize the oral health distortions still prevailing in developing countries like Brazil.

  13. Irradiation effects in UO2 and CeO2

    International Nuclear Information System (INIS)

    Ye, Bei; Oaks, Aaron; Kirk, Mark; Yun, Di; Chen, Wei-Ying; Holtzman, Benjamin; Stubbins, James F.

    2013-01-01

    Single crystal CeO 2 , as a surrogate material to UO 2 , was irradiated with 500 keV xenon ions at 800 °C while being observed using in situ transmission electron microscopy (TEM). Experimental results show the formation and growth of defect clusters including dislocation loops and cavities as a function of increasing atomic displacement dose. At high dose, the dislocation loop structure evolves into an extended dislocation line structure, which appears to remain stable to the high dose levels examined in this study. A high concentration of cavities was also present in the microstructure. Despite high atomic displacement doses, the specimen remained crystalline to a cumulated dose of 5 × 10 15 ions/cm 2 , which is consistent with the known stability of the fluorite structure under high dose irradiation. Kinetic Monte Carlo calculations show that oxygen mobility is substantially higher in hypo-stoichiometric UO 2 /CeO 2 than hyper-stoichiometric systems. This result is consistent with the ability of irradiation damage to recover even at intermediate irradiation temperatures

  14. CEO emotional bias and investment decision, Bayesian network method

    Directory of Open Access Journals (Sweden)

    Jarboui Anis

    2012-08-01

    Full Text Available This research examines the determinants of firms’ investment introducing a behavioral perspective that has received little attention in corporate finance literature. The following central hypothesis emerges from a set of recently developed theories: Investment decisions are influenced not only by their fundamentals but also depend on some other factors. One factor is the biasness of any CEO to their investment, biasness depends on the cognition and emotions, because some leaders use them as heuristic for the investment decision instead of fundamentals. This paper shows how CEO emotional bias (optimism, loss aversion and overconfidence affects the investment decisions. The proposed model of this paper uses Bayesian Network Method to examine this relationship. Emotional bias has been measured by means of a questionnaire comprising several items. As for the selected sample, it has been composed of some 100 Tunisian executives. Our results have revealed that the behavioral analysis of investment decision implies leader affected by behavioral biases (optimism, loss aversion, and overconfidence adjusts its investment choices based on their ability to assess alternatives (optimism and overconfidence and risk perception (loss aversion to create of shareholder value and ensure its place at the head of the management team.

  15. CEO- CNE relationships: building an evidence-base of chief nursing executive replacement costs.

    Science.gov (United States)

    Sredl, Darlene; Peng, Niang-Huei

    2010-06-03

    Explore professional relationships between Chief Nurse Executives (CNEs) and Chief Executive Officers (CEOs); CNE ethnic diversity; and CNE replacement costs. Theoretical frameworks - Marilyn Ray's Theory of Bureaucratic Caring, and Turkel's Theory of Relational Complexity espousing economic as well as caring variables. Exploratory mixed-method descriptive design using CNE mailed survey. CNE- cited opportunities for maintaining a positive relationship with the CEO: respect for CEO; goal- sharing (r=.782, p<0.01); having a strong relationship (r= .718, p<0.01); co-problem-solving (r=.437, p<0.01); having an interesting job (r=.406, p<0.01); having similar interests with CEO (r= .346, p<0.01); CEO and CNE maintaining specific roles (r= .261, p<0.05); satisfaction with CNE income (r=.251, p<0.05); willingness to improve relationship with CEO (r=.254, p<0.05). CNE positions demonstrated an ethnic diversity factor of 0.03%. CNE replacement costs to healthcare facilities were over 1.5 million dollars. CNE/CEO relationships have identified cohesive factors that may contribute to CNE longevity in position; an ethically diverse CNE deficit exists; and, CNE turnover and vacancy rates impact an organization's financial health and quality of care.

  16. Bio diesel synthesis from pongamia pinnata oil over modified CeO2 catalysts

    International Nuclear Information System (INIS)

    Venkatesh; Sathgatta Z, M. S.; Manjunatha, S.; Thammannigowda V, V.

    2014-01-01

    This study investigates the use of CeO 2 , ZrO 2 , Mg O and CeO 2 -ZrO 2 , CeO 2 -Mg O, CeO 2 -ZrO 2 -Mg O mixed oxides as solid base catalysts for the transesterification of Pongamia pinnata oil with methanol to produce bio diesel. SO 4 2- /CeO 2 and SO 4 2- /CeO 2 -ZrO 2 were also prepared and used as solid acid catalysts for esterification of Pongamia pinnata oil (P-oil) to reduce the % of free fatty acid (FFA) in P-oil. The oxide catalysts were prepared by an incipient wetness impregnation method and characterized by techniques such as NH 3 -Tpd for surface acidity, CO 2 -Tpd for surface basicity and powder X-ray diffraction for crystallinity. The effect of nature of the catalyst, methanol to P-oil molar ratio and reaction time in esterification as well as in transesterification was investigated. The catalytic materials were reactive d and reused for five reaction cycles and the results showed that the ceria based catalysts have reasonably good reusability both in esterification and transesterification reaction. The test results also revealed that the CeO 2 -ZrO 2 modified with Mg O could have potential for use in the large scale bio diesel production. (Author)

  17. Effects of Surfactants on the Performance of CeO2 Humidity Sensor

    Directory of Open Access Journals (Sweden)

    Chunjie Wang

    2014-01-01

    Full Text Available Nanosized CeO2 powders were synthesized via hydrothermal method with different types of surfactants (polyethylene glycol (PEG, cetyltrimethylammonium bromide (CTAB, and sodium dodecylbenzenesulfonate (SDBS. X-ray diffraction, Raman spectroscopy, and transmission electron microscopy were utilized to characterize the phase structures and morphologies of the products. The sample with CTAB as surfactant (CeO2-C has the largest specific surface area and the smallest particle size among these three samples. The humidity sensor fabricated by CeO2-C shows higher performance than those used CeO2-P and CeO2-S. The impedance of the CeO2-C sensor decreases by about five orders of magnitude with relative humidity (RH changing from 15.7 to 95%. The response and recovery time are 7 and 7 s, respectively. These results indicate that the performance of CeO2 humidity sensors can be improved effectively by the addition of cationic surfactant.

  18. Design of high quality doped CeO2 solid electrolytes with nanohetero structure

    International Nuclear Information System (INIS)

    Mori, T.; Ou, D.R.; Ye, F.; Drennan, J.

    2006-01-01

    Doped cerium (CeO 2 ) compounds are fluorite related oxides which show oxide ionic conductivity higher than yttria-stabilized zirconia in oxidizing atmosphere. As a consequence of this, a considerable interest has been shown in application of these materials for low (400-650 o C) temperature operation of solid oxide fuel cells (SOFCs). In this paper, our experimental data about the influence of microstructure at the atomic level on electrochemical properties were reviewed in order to develop high quality doped CeO 2 electrolytes in fuel cell applications. Using this data in the present paper, our original idea for a design of nanodomain structure in doped CeO 2 electrolytes was suggested. The nanosized powders and dense sintered bodies of M doped CeO 2 (M:Sm,Gd,La,Y,Yb, and Dy) compounds were fabricated. Also nanostructural features in these specimens were introduced for conclusion of relationship between electrolytic properties and domain structure in doped CeO 2 . It is essential that the electrolytic properties in doped CeO 2 solid electrolytes reflect in changes of microstructure even down to the atomic scale. Accordingly, a combined approach of nanostructure fabrication, electrical measurement and structure characterization was required to develop superior quality doped CeO 2 electrolytes in the fuel cells. (author)

  19. Homogeneously dispersed CeO2 nanoparticles on exfoliated hexaniobate nanosheets

    Science.gov (United States)

    Marques, Thalles M. F.; Strayer, Megan E.; Ghosh, Anupama; Silva, Alexandre; Ferreira, Odair P.; Fujisawa, Kazunori; Alves da Cunha, Jose R.; Abreu, Guilherme J. P.; Terrones, Mauricio; Mallouk, Thomas E.; Viana, Bartolomeu C.

    2017-12-01

    Hexaniobate nanosheets derived from the parent compound K4Nb6O17 have been decorated with CeO2 nanoparticles by ion exchange with aqueous cerium (IV) solution. Very homogeneous CeO2 nanoparticle decoration of the hexaniobate sheets can be achieved by this method and the resulting composites may absorb visible light. HRTEM images show that ∼3.0 nm diameter CeO2 nanoparticles adhere to hexaniobate nanosheets that are exfoliated and then restacked prior to Ce deposition. The interfacial interaction between CeO2 nanoparticles and nanosheets would be due to an electrostatic attraction mechanism. Raman and XRD measurements have given strong evidence that CeO2 nanoparticles have fluorite structure. EDS, FTIR and XPS results suggest almost complete exchange of TBA+ and K+ by Ce4+. Cerium ion exchange on the acid exchanged parent compound, H2.9K1.1Nb6O17, revealed that the extent of Ce ion exchange is much greater in case of nanosheets, which may be rationalized by the larger surface area available after exfoliation. XPS measurements show that the ratio of Ce4+/Ce3+ is around 4.4, in agreement with the formation of fluorite structure (CeO2). Thus, these CeO2 nanoparticle/nanosheet composites may be useful for catalytic processes.

  20. Inverse CeO2sbnd Fe2O3 catalyst for superior low-temperature CO conversion efficiency

    Science.gov (United States)

    Luo, Yongming; Chen, Ran; Peng, Wen; Tang, Guangbei; Gao, Xiaoya

    2017-09-01

    The paper presents a rational design of highly efficient and affordable catalysts for CO oxidation with a low operating temperature. A series of ceria-iron catalysts were inversely built via a co-precipitation method. The catalytic activity of low-temperature CO oxidation was much higher with CeO2-modified Fe2O3 (CeO2sbnd Fe2O3) than with Fe2O3-modified CeO2 (Fe2O3sbnd CeO2). In particular, the 7.5% CeO2sbnd Fe2O3 catalyst had the highest activity, reaching 96.17% CO conversion at just 25 °C. Catalyst characterization was carried out to explore the cause of the significantly different CO conversion efficiencies between the Fe2O3sbnd CeO2 and Fe2O3sbnd CeO2 catalysts. HRTEM showed a significant inhomogeneous phase in 7.5% CeO2sbnd Fe2O3 with small CeO2 nanoparticles highly dispersed on the rod-shaped Fe2O3 surface. Furthermore, the 7.5% CeO2sbnd Fe2O3 composite catalyst exhibited the highest ratios of Fe2+/Fe3+ and Ce3+/Ce4+ as well as the largest pore volume. These properties are believed to benefit the CO conversion in 7.5% CeO2sbnd Fe2O3.

  1. Update on Activities of CEOS Disaster Management Support Group

    Science.gov (United States)

    Wood, H. M.; Lauritson, L.

    The Committee on Earth Observation Satellites (CEOS) Disaster Management Support Group (DMSG) has supported natural and technological disaster management on a worldwide basis by fostering improved utilization of existing and planned Earth Observation (EO) satellite data. The DMSG has focused on developing and refining recommendations for the application of satellite data to selected hazard areas--drought, earthquake, fire, flood, ice, landslide, oil spill, and volcanic hazards. Particular emphasis was placed on working closely with space agencies, international and regional organizations, and commercial organizations on the implementation of these recommendations. The DMSG is in its last year with its primary focus on documenting its work and migrating on going activities to other fora. With over 300 participants from more than 140 organizations, the DMSG has found strong support among CEOS space agencies and the Integrated Global Observing Strategy (IGOS), as well as an enthusiastic reception from numerous international, regional, and national emergency managers, and distinct interest from the commercial sector. In addition, the group has worked to give full support to the work of the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) in pursuit of decisions taken at UNISPACE III and the United Nations International Strategy on Disaster Reduction (ISDR). In conjunction with the IGOS, several of the DMSG hazards teams (earthquake, landslide, and solid Earth dimensions of volcanoes) are joining in the effort to develop an IGOS Geohazards theme team. Cooperation efforts with organizations such as IGOS, COPUOS, and ISDR will hopefully lead to the pick up of much of the on going DMSG activities. Since the inception of this ad hoc working group and its predecessor project, the DMSG has developed and refined recommendations for the application of satellite data by bringing together experts from eight hazard areas to identify user needs, as well as

  2. Non-Performance Pay and Relational Contracting: Evidence from CEO Compensation

    DEFF Research Database (Denmark)

    DeVaro, Jed; Kim, Jin-Hyuk; Vikander, Nick

    2017-01-01

    CEOs are routinely compensated for aspects of firm performance that are beyond their control. This is puzzling from an agency perspective, which assumes performance pay should be efficient. Working within an agency framework, we provide a rational for this seemingly inefficient feature of CEO...... compensation by invoking the idea of informal agreements, specifically the theory of relational contracting. We derive observable implications to distinguish relational from formal contracting and, using ExecuComp data, find that CEOs' annual cash and equity incentive payments positively correlate...... with the cyclical component of sales and respond to measures of persistence as relational contracting theory predicts....

  3. Buprenorfina-naloxona en el tratamiento de la dependencia a opiáceos

    OpenAIRE

    Martínez, Beatriz; Donat, Lucas; Soler Company, Enrique; Ferrando Piqueres, Raúl; Pérez Prior, Noemí; Romero Barco, Rocío

    2007-01-01

    En los últimos diez años la buprenorfina ha aumentado su disponibilidad en Europa como alternativa a la metadona en el tratamiento de la dependencia a opiáceos. La buprenorfina es un opiáceo sintético con actividad agonista parcial utilizado en el tratamiento de sustitución de la dependencia a opiáceos. Diversos estudios han demostrado que posee una eficacia superior a placebo y similar a metadona.Con el fin de disminuir el uso inadecuado de la buprenorfina por vía intravenosa, en octubre de ...

  4. Controlled hydrothermal synthesis of CeO2 nanospheres and their excellent magnetic properties

    Science.gov (United States)

    Niu, Xiaofei

    2017-04-01

    Monodisperse spherical CeO2 nanostructures with irregular and rough surfaces have successfully been synthesized via a facile hydrothermal technology. XRD, SEM, XPS, Raman scattering, and M-H curves were employed to characterize the samples. The results showed that the spherical CeO2 nanostructures have a cubic fluorite structure and that there are Ce3+ ions and oxygen vacancies in the surface of the samples. The M-H curve of CeO2 nanospheres exhibits excellent room-temperature ferromagnetism (RT-FM), which is likely ascribed to the effects of the Ce3+ ions and oxygen vacancies.

  5. DIAGNOSTIC GUIDANCE AND EARLY INTERVENTION IN CLASS III MALOCCLUSION

    Directory of Open Access Journals (Sweden)

    Rinandri Charea Runizar

    2015-06-01

    Full Text Available Timing of orthodontic treatment for Class III malocclusion has always been somewhat controversial. Many orthodontic pioneers like Angle, Tweed, and Graber have advocated early interception of class II malocclusion because this kind of skeletal discrepancy once established, would usually progress rapidly. What kind of early treatment would be appropriate for this malocclusion? Would this approach be effective and promises a stable result? Early orthodontic treatment is defined as a treatment that is initiated during the primary or mixed dentition stage to enhance skeletal and dental development. It is usually done in two phases. The first phase is intended to correct skeletal discrepancy by taking advantage of growth and development period. The second phase followed to improve occlusal relationship. Early treatment of Class III malocclusion is a possible alternative to improve skeletal discrepancy or at the very east may serve to prevent a worsening malocclusion. Principles of Class III early treatment depend on whether it is dental Class III, functional Class III, or skeletal Class III. Practitioners should consider positive and negative factors of a patient before initiating treatment. Likewise, they should understand factors that affect prognosis and stability of the results.

  6. Eu and Sr2CeO4 : Eu phosphors suitable for near ultraviolet excitation

    Indian Academy of Sciences (India)

    Administrator

    et al 2009). It absorbs ultraviolet radiation and emits white light, when activated by Eu2+ ions. It is anticipated that the dual behaviour of Sr2CeO4 : Eu3+ and Sr2CeO4 : Eu2+ phosphors ... in stoichiometric proportions (Sr : Ce is 2 : 1) and Eu2O3. (National ..... Zhang C X, Jiang W J and Yang X J 2009 J. Alloys Compd. 474.

  7. Synthesis of Mn-doped CeO2 nanorods and their application as ...

    Indian Academy of Sciences (India)

    The responses to humidity for static and dynamic testing proved dopingMn into CeO2 can improve the humidity sensitivity. For the sample with Mn% about 1.22, the resistance changes from 375.3 to 2.7M as the relative humidity (RH) increases from 25 to 90%, indicating promising applications of the Mn-doped CeO2 ...

  8. The Impact of Entrepreneur-CEOs in Microfinance Institutions: A Global Survey

    OpenAIRE

    Randøy, Trond; Strøm, R. Øystein; Mersland, Roy

    2015-01-01

    Microfinance is a global high-growth industry, in which entrepreneurship is prevalent and substantial. Based on the theoretical argument that microfinance entrepreneur-CEOs are “motivated agents” with a unique ability to hire and socialize mission-oriented staff, we hypothesize that these CEOs produce more sustainable microfinance institutions with better social performance and lower costs. This study utilizes data from 295 microfinance institutions in 73 developing countries, assessed betwee...

  9. CEO Succession and Firm Performance: Evidence from Publicly Listed Malaysian Firms

    OpenAIRE

    Rokiah Ishak; Ku Nor Izah Ku Ismail; Shamsul Nahar Abdullah

    2013-01-01

    This study investigates the impact of CEO succession on the financial performance of publicly listed Malaysian firms. A match-paired t-test and Wilcoxon signed-rank test are used to determine if there is a change in firm performance following CEO succession. The overall results show that performance improves following post-succession. We also find significant improvement in the performance of companies that experienced forced turnovers and subsequently selected outsiders as successors. On the...

  10. New CeO2 nanoparticles-based topical formulations for the skin protection against organophosphates

    Directory of Open Access Journals (Sweden)

    Arnaud Zenerino

    2015-01-01

    Full Text Available To reinforce skin protection against organophosphates (OPs, the development of new topical skin protectants (TSP has received a great interest. Nanoparticles like cerium dioxide (CeO2 known to adsorb and neutralize OPs are interesting candidates for TSP. However, NPs are difficult to disperse into formulations and they are suspected of toxicological issues. Thus, we want to study: (1 the effect of the addition of CeO2 NPs in formulations for the skin protection (2 the impact of the doping of CeO2 NPs by calcium; (3 the effect of two methods of dispersion of CeO2 NPs: an O/W emulsion or a suspension of a fluorinated thickening polymer (HASE-F grafted with these NPs. As a screening approach we used silicone membranes as a skin equivalent and Franz diffusion cells for permeation tests. The addition of pure CeO2 NPs in both formulations permits the penetration to decrease by a 3–4-fold factor. The O/W emulsion allows is the best approach to obtain a film-forming coating with a good reproducibility of the penetration results; whereas the grafting of NPs to a thickener is the best way to obtain an efficient homogenous suspension of CeO2 NPs with a decreased of toxicological impact but the coating is less film-forming which slightly impacts the reproducibility of the penetration results.

  11. Influence of dopant concentration on spectroscopic properties of Sr2CeO4:Yb nanocrystals

    Science.gov (United States)

    Stefanski, M.; Kędziorski, A.; Hreniak, D.; Strek, W.

    2017-12-01

    Optical properties of Sr2CeO4:Yb nanocrystals synthesized via Pechini's method are reported. The samples were characterized by X-ray diffraction data measurements. The unit cell parameters were determined using Rietveld refinement. It was found that they decreased with increasing amount of Yb ions. The absorption, excitation, emission spectra and luminescence decay profiles of the Sr2CeO4:Yb nanocrystals were investigated. It was observed that optical properties were strongly dependent on Yb concentration. It was found that Yb3+-O2- charge transfer transitions have great influence on the absorption spectra. It can be seen in the emission spectra that in addition to standard bands/lines corresponding to Ce-O metal-to-ligand charge transfer of Sr2CeO4 and f-f transitions of Yb3+, there is emission band centered at 744 nm. Its intensity depends on the concentration of the dopant. Recorded decay times become shorter with increasing dopant concentration due to the Yb3+ concentration quenching. Excitation spectra indicate the energy transfer from Ce-O charge transfer states to Yb3+2F5/2 state. The issue of appearance of down-conversion process in Sr2CeO4:Yb nanocrystals is considered.

  12. Experimental evidence for self-assembly of CeO2 particles in solution: Formation of single-crystalline porous CeO2 nanocrystals

    DEFF Research Database (Denmark)

    Tan, Hui Ru; Tan, Joyce Pei Ying; Boothroyd, Chris

    2012-01-01

    Single-crystalline porous CeO2 nanocrystals, with sizes of ∼20 nm and pore diameters of 1-2 nm, were synthesized successfully using a hydrothermal method. Using electron tomography, we imaged the three-dimensional structure of the pores in the nanocrystals and found that the oriented aggregation ...... energy-loss spectroscopy. The oxygen vacancies might play an important role in oxygen diffusion in the crystals and the catalytic activities of single-crystalline porous CeO 2 structures. © 2011 American Chemical Society....

  13. A facile synthesis of high quality nanostructured CeO2 and Gd2O3-doped CeO2 solid electrolytes for improved electrochemical performance.

    Science.gov (United States)

    Kuo, Yu-Lin; Su, Yu-Ming; Chou, Hung-Lung

    2015-06-07

    This study describes the use of a composite nitrate salt solution as a precursor to synthesize CeO2 and Gd2O3-doped CeO2 (GDC) nanoparticles (NPs) using an atmospheric pressure plasma jet (APPJ). The microstructures of CeO2 and GDC NPs were found to be cubical and spherical shaped nanocrystallites with average particle sizes of 10.5 and 6.7 nm, respectively. Reactive oxygen species, detected by optical emission spectroscopy (OES), are believed to be the major oxidative agents for the formation of oxide materials in the APPJ process. Based on the material characterization and OES observations, the study effectively demonstrated the feasibility of preparing well-crystallized GDC NPs by the APPJ system as well as the gas-to-particle mechanism. Notably, the Bader charge of CeO2 and Ce0.9Gd0.1O2 characterized by density function theory (DFT) simulation and AC impedance measurements shows that Gd helps in increasing the charge on Ce0.9Gd0.1O2 NPs, thus improving their conductivity and making them candidate materials for electrolytes in solid oxide fuel cells.

  14. Interaction of Pd single atoms with different CeO2 crystal planes: A first-principles study

    Science.gov (United States)

    He, Bingling; Wang, Jinlong; Ma, Dongwei; Tian, Zhixue; Jiang, Lijuan; Xu, Yan; Cheng, Sujun

    2018-03-01

    The adsorption of single Pd atoms on the various CeO2 surfaces, including (111), (110), and (100), has been studied based on the first-principles calculations. It is found that, according to the calculated adsorption energy, interaction strength between Pd and the three CeO2 surfaces follows the order of (100) > (110) > (111). Interestingly, the effect of the electron localization on the surface Ce ions due to the Pd adsorption on its adsorption stability is more significant for the (110) surface than that for the (111) and (100) surfaces. We also find that the formal oxidation states of Pd0, Pdδ+ (δ < 1) and Pd1+ may appear on the CeO2 (111) surface, and Pdδ+ (δ < 1) and Pd1+ could coexist on the CeO2 (100) surfaces. However, under suitable conditions the CeO2 (110) surface may be covered with Pd2+ ions. Present theoretical results clearly suggest that the interaction between Pd and CeO2 nanocrystals significantly depends on the crystal planes of CeO2. It is expected that our study will give useful insights into the effect of CeO2 crystal plane on the physicochemical and catalytic properties of CeO2 supported Pd catalyst.

  15. The reasons why the CEO of ARPANSA issued the Licence to ANSTO

    International Nuclear Information System (INIS)

    Loy, J.

    2002-01-01

    After the process of assessment, the Chief Executive Officer (CEO) of ARPANSA has reached the conclusion that ANSTO's Replacement Research Reactor (RRR) design would result in a reactor that could be operated safely. Of fundamental importance is that its core can be shutdown by gravity operated systems. That is, it is relying on laws of nature, without any other form of intervention. The reactor also has important safety features built into it that meet international best practice in radiation protection and nuclear safety. It has two separate and diverse shutdown systems that can operate to shut down the reactor in any abnormal occurrence. The ability of these systems to achieve the necessary shutdown in a whole range of potential accident scenarios was a central focus of the safety assessment that made. In reaching this decision, consideration was given to the issues of spent fuel and radioactive waste management. These were very major issues in the public's mind as they were the subject of the great majority of public submissions received and considered. ANSTO's proposed route for dealing with spent fuel is that it will be shipped to France for reprocessing in the COGEMA facility at La Hague. The waste from this reprocessing would be returned to Australia as vitrified waste, suitable for long term storage.This is a viable and acceptably safe strategy. As a fall back option, ANSTO relies on its contract with the Argentinean company, Investigacion Aplicada (INVAP) that requires INVAP to find an alternative route for the processing of the RRR spent fuel into an acceptable waste form for its storage in Australia. The amount of spent fuel ultimately is not very large and does not need the enormous processing facilities that exist in France and the United Kingdom for the reprocessing of fuel from power reactors in Europe and Japan. The issue of the long term storage of the intermediate level waste arising from the processing of spent fuel is also debated. The

  16. Toward transparent nanocomposites based on polystyrene matrix and PMMA-grafted CeO2 nanoparticles.

    Science.gov (United States)

    Parlak, Onur; Demir, Mustafa M

    2011-11-01

    The association of transparent polymer and nanosized pigment particles offers attractive optical materials for various potential and existing applications. However, the particles embedded into polymers scatter light due to refractive index (RI) mismatch and reduce transparency of the resulting composite material. In this study, optical composites based on polystyrene (PS) matrix and poly(methyl methacrylate) (PMMA)-grafted CeO(2) hybrid particles were prepared. CeO(2) nanoparticles with an average diameter of 18 ± 8 nm were precipitated by treating Ce(NO(3))·6H(2)O with urea in the presence of a polymerizable surfactant, 3-methacyloxypropyltrimethoxy silane. PMMA chains were grafted on the surface of the nanoparticles upon free radical in situ solution polymerization. While blending of unmodified CeO(2) particles with PS resulted in opaque films, the transparency of the composite films was remarkably enhanced when prepared by PMMA-grafted CeO(2) hybrid particles, particularly those having a PMMA thickness of 9 nm. The improvement in transparency is presumably due to the reduction in RI mismatch between CeO(2) particles and the PS matrix when using PMMA chains at the interface.

  17. Fate and effects of CeO2 nanoparticles in aquatic ecotoxicity tests.

    Science.gov (United States)

    Van Hoecke, Karen; Quik, Joris T K; Mankiewicz-Boczek, Joanna; De Schamphelaere, Karel A C; Elsaesser, Andreas; Van der Meeren, Paul; Barnes, Clifford; McKerr, George; Howard, C Vyvyan; Van de Meent, Dik; Rydzyński, Konrad; Dawson, Kenneth A; Salvati, Anna; Lesniak, Anna; Lynch, Iseult; Silversmit, Geert; De Samber, Björn; Vincze, Laszlo; Janssen, Colin R

    2009-06-15

    Cerium dioxide nanoparticles (CeO2 NPs) are increasingly being used as a catalyst in the automotive industry. Consequently, increasing amounts of CeO2 NPs are expected to enter the environment where their fate in and potential impacts are unknown. In this paper we describe the fate and effects of CeO2 NPs of three different sizes (14, 20, and 29 nm) in aquatic toxicity tests. In each standard test medium (pH 7.4) the CeO2 nanoparticles aggregated (mean aggregate size approximately 400 nm). Four test organisms covering three different trophic levels were investigated, i.e., the unicellular green alga Pseudokirchneriella subcapitata, two crustaceans: Daphnia magna and Thamnocephalus platyurus, and embryos of Danio rerio. No acute toxicity was observed for the two crustaceans and D. rerio embryos, up to test concentrations of 1000, 5000, and 200 mg/L, respectively. In contrast, significant chronic toxicity to P. subcapitata with 10% effect concentrations (EC10s) between 2.6 and 5.4 mg/L was observed. Food shortage resulted in chronic toxicity to D. magna, for wich EC10s of > or = 8.8 and or = 0.052 and effect of dissolved Ce or CeO2 NP uptake or adsorption, nor to an indirect effect of nutrient depletion (by sorption to NPs) or physical light restriction (through shading by the NPs). However, observed clustering of NPs around algal cells may locally cause a direct or indirect effect.

  18. Diversity begets diversity? The effects of board composition on the appointment and success of women CEOs.

    Science.gov (United States)

    Cook, Alison; Glass, Christy

    2015-09-01

    Previous research on the effects of leadership diversity on firm outcomes has produced inconsistent and inconclusive findings. While some scholars argue that diversity increases organizational equity and enhances performance, others argue that diversity increases conflict, reduces cooperation and harms performance. This study tests the impact of a variety of compositional factors on firm outcomes. Specifically, we analyze whether and how board composition affects the advancement and mobility of women CEOs and firm performance. Our analysis relies on a unique data set of all Chief Executive Officers (CEOs) and Board of Directors (BODs) in Fortune 500 companies over a ten-year period. We find a marginally significant positive relationship between board diversity and the likelihood of a woman being appointed CEO. We further find that board diversity significantly and positively influences the post-promotion success of women CEOs. Our findings suggest that board composition is critical for the appointment and success of women CEOs, and increasing board diversity should be central to any organizational diversity efforts. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. The Namibia Early Flood Warning System, A CEOS Pilot Project

    Science.gov (United States)

    Mandl, Daniel; Frye, Stuart; Cappelaere, Pat; Sohlberg, Robert; Handy, Matthew; Grossman, Robert

    2012-01-01

    Over the past year few years, an international collaboration has developed a pilot project under the auspices of Committee on Earth Observation Satellite (CEOS) Disasters team. The overall team consists of civilian satellite agencies. For this pilot effort, the development team consists of NASA, Canadian Space Agency, Univ. of Maryland, Univ. of Colorado, Univ. of Oklahoma, Ukraine Space Research Institute and Joint Research Center(JRC) for European Commission. This development team collaborates with regional , national and international agencies to deliver end-to-end disaster coverage. In particular, the team in collaborating on this effort with the Namibia Department of Hydrology to begin in Namibia . However, the ultimate goal is to expand the functionality to provide early warning over the South Africa region. The initial collaboration was initiated by United Nations Office of Outer Space Affairs and CEOS Working Group for Information Systems and Services (WGISS). The initial driver was to demonstrate international interoperability using various space agency sensors and models along with regional in-situ ground sensors. In 2010, the team created a preliminary semi-manual system to demonstrate moving and combining key data streams and delivering the data to the Namibia Department of Hydrology during their flood season which typically is January through April. In this pilot, a variety of moderate resolution and high resolution satellite flood imagery was rapidly delivered and used in conjunction with flood predictive models in Namibia. This was collected in conjunction with ground measurements and was used to examine how to create a customized flood early warning system. During the first year, the team made use of SensorWeb technology to gather various sensor data which was used to monitor flood waves traveling down basins originating in Angola, but eventually flooding villages in Namibia. The team made use of standardized interfaces such as those articulated

  20. CEO perceptions of competition--and strategic response in hospital markets.

    Science.gov (United States)

    Alexander, J A; Burns, L R; Morrisey, M A; Johnson, V

    2001-06-01

    Physician-organization integration (POI) has emerged as a key issue for hospitals and health systems seeking to improve the quality and cost-effectiveness of care. Although competition and managed care are often cited as primary market drivers of the adoption of POI strategies, prior research has shown only weak associations between these market attributes and POI. This article argues that the role of key organizational decision makers has not been adequately accounted for in explaining strategic change. The study examines the role of hospital CEO perceptions of competition in predicting the adoption of five different approaches to POI. CEO perceptions of general market competition are explained by a combination of market and organizational attributes. Furthermore, when controlling for objective characteristics of the environment and organization, CEO perceptions of competition have consistent, statistically significant associations with four of five measures of POI examined.

  1. Role of Social Relations of Outside Directors with CEO in Earnings Management

    Directory of Open Access Journals (Sweden)

    Muhammad Shaique

    2017-12-01

    Full Text Available The purpose of this study is to examine the impact of social relations among the board members on earnings management in Pakistani listed companies. Specifically, we have analyzed the social networks between CEO and outside board members. The modified Jones model has been used in this study to measure earnings management and we have captured social relations through SOCIAL (Social networking index. Our results suggest that firms with more connected boards show a positive relationship between board independence and earnings management. Further, we have shown that firms with CEO duality exhibit a higher association between social connections of the board and earnings management than firms with non-duality. Social relations among the board members undermine monitoring ability of outside directors and the impact becomes more severe in the presence of CEO duality.

  2. Structural, morphological, Raman, optical, magnetic, and antibacterial characteristics of CeO2 nanostructures

    Science.gov (United States)

    Abbas, Fazal; Iqbal, Javed; Jan, Tariq; Badshah, Noor; Mansoor, Qaisar; Ismail, Muhammad

    2016-01-01

    In this study, CeO2 nanostructures were synthesized by a soft chemical method. A hydrothermal treatment was observed to lead to an interesting morphological transformation of the nanoparticles into homogeneous microspheres composed of nanosheets with an average thickness of 40 nm. Structural analysis revealed the formation of a single-phase cubic fluorite structure of CeO2 for both samples. A Raman spectroscopic study confirmed the XRD results and furthermore indicated the presence of a large number of oxygen vacancies in the nanosheets. These oxygen vacancies led to room-temperature ferromagnetism (RTFM) of the CeO2 nanosheets with enhanced magnetic characteristics. Amazingly, the nanosheets exhibited substantially greater antibacterial activity than the nanoparticles. This greater antibacterial activity was attributed to greater exposure of high-surface-energy polar surfaces and to the presence of oxygen vacancies.

  3. Does obfuscating excessive CEO pay work? The influence of remuneration report readability on say-on-pay votes

    NARCIS (Netherlands)

    Hooghiemstra, Reggy; Kuang, Yu Flora; Qin, Bo

    2017-01-01

    This paper assesses whether reducing ‘readability’ is an effective obfuscation strategy for influencing the level of shareholder say-on-pay voting dissent in firms with excessive CEO pay. Based on a sample of UK-listed firms, our results indicate that in cases of excessive CEO pay, a less readable

  4. An Evaluation of the Potential Phototoxicity of CeO2 Nanoparticles in Retinal Pigment Epithelial Cells in-vitro

    Science.gov (United States)

    Cerium dioxide (CeO2) engineered nanoparticles (NP) are used as fuel-borne catalysts in off-road diesel engines, which can lead to exhaust emissions of respirable CeO2 NP. Other metal oxides may act as photo-catalysts which induce the generation of free radicals upon exposure to ...

  5. Synthesis, Structural and Optical Characterization of Sol-Gel-Derived Y-Doped Mesoporous CeO2

    Science.gov (United States)

    Lee, Ying Chieh; Li, Kun-Dar; Lu, Cheng-Hsueh; Shen, Jung-Hsiung; Teoh, Lay Gaik; Chiang, Ghi Wei

    2013-08-01

    Highly crystalline and thermally stable undoped CeO2 and Y-doped mesoporous CeO2 particles have been synthesized from cerium(III) nitrate hexahydrate [Ce(NO3)3·6H2O] by the sol-gel method. Mesoporous CeO2 doped with 2 mol.% Y2O3 and calcined at 500°C possesses specific surface area of 130.39 m2/g and retains a surface area of 91.84 m2/g at 600°C. In comparison, undoped calcined materials have smaller specific surface areas of 43.23 m2/g and 20.24 m2/g at 500°C and 600°C, respectively. Results from x-ray diffraction (XRD) analysis, Raman spectroscopy, and selected-area electron diffraction (SAED) analysis indicated that the synthesized undoped CeO2 and Y-doped mesoporous CeO2 have the fluorite structure of bulk CeO2. The crystallite size of CeO2 is also considerably reduced by doping. The optical bandgap was found to be 3.24 eV for the undoped and 3.36 eV for the doped samples with calcination at 600°C. These results suggest that there are potential applications of Y-doped mesoporous CeO2 with nanocrystals in the design of photocatalysts and optical devices.

  6. Effect of CeO2 addition on electrical and optical properties of lithium borate glasses

    International Nuclear Information System (INIS)

    Gedam, R.S.; Ramteke, D.D.

    2011-01-01

    Rare earth (RE) ions play an important role in modern technology as an active ion in many optical materials. RE-doped glasses were used in many optical devices because of abundant number of the absorption and emission bands arising from the transitions between the RE elements energy levels. Among all rare earth, glasses containing CeO 2 are extensively studied for scintillating applications. Radiation length of CeO 2 containing lithium silicate glasses decreases and absorption edge in transmittance shift towards longer wavelength. In the present study an attempt has been made to verify similar results in borate containing glasses. Therefore glass series 15Li 2 O-xCeO 2 -(85''x)B 2 O 3 where x= 0.25, 0.5, 0.75, 1 mol% was prepared by conventional melt quench technique. Their electrical and optical properties have been investigated. It is observed that the conductivity of these glasses decreases while density, glass transition temperature and refractive index increases with the addition of CeO 2 . The conductivity of the glasses is mostly controlled by the activation energy. Since the lithium fraction in the present series is kept constant, the decrease in conductivity for glasses may be attributed to the reduction in the number of available vacant sites for the mobile lithium ions when boron is substituted with CeO 2 . The radiation length was determined using density values and it was found to decrease with the addition of CeO 2 . The absorption coefficient a were determined near the absorption edge of different photon energy for all glass samples and plot of (αhν) 1/2 Vs. hν (Tauc's plot) is shown. It is observed that the optical band gap energy (E g Opt ) decreases with the addition of CeO 2

  7. CeO2-stabilized tetragonal ZrO2 polycrystals (Ce-TZP ceramics)

    International Nuclear Information System (INIS)

    Andrade Nono, M.C. de.

    1990-12-01

    This work presents the development and the characterization of CeO 2 -stabilized tetragonal ZrO 2 polycrystals (Ce-TZP ceramics), since it is considered candidate material for applications as structural high performance ceramics. Sintered ceramics were fabricated from mixtures of powders containing different CeO 2 content prepared by conventional and nonconventional techniques. These powders and their resultant sintered ceramics were specified by chemical and physical characterization, compactation state and mechanical properties. The chemical characteristics were determined by chemical analysis and the physical characteristics were evaluated by phase content, particle and agglomerate size and aspect, and powder porosity. (author)

  8. CeO2 based catalysts for the treatment of propylene in motorcycle's exhaust gases

    OpenAIRE

    Pham, Phuong Thi Mai; Minh, Thang Le; Nguyen, Tien The; Van Driessche, Isabel

    2014-01-01

    In this work, the catalytic activities of several single metallic oxides were studied for the treatment of propylene, a component in motorcycles? exhaust gases, under oxygen deficient conditions. Amongst them, CeO2 is one of the materials that exhibit the highest activity for the oxidation of C3H6. Therefore, several mixtures of CeO2 with other oxides (SnO2, ZrO2, Co3O4) were tested to investigate the changes in catalytic activity (both propylene conversion and CO2 selectivity). Ce0.9Zr0.1O2,...

  9. Why are so few females promoted into CEO and vice-president positions?

    DEFF Research Database (Denmark)

    Smith, Nina; Smith, Valdemar; Verner, Mette

    In most OECD countries, only very few women succeed in reaching top executive positions. In this paper, the probability of promotion into VP and CEO positions is estimated based on employer-employee data on all Danish companies observed during the period 1997-2007. After controlling for a large...... number of family-related variables, including take-up history of maternity and paternity leave and proxies for 'female-friendly' companies, there is still a considerable gap in the promotion probabilities for CEO positions, but not for VP positions. Thus, the results cannot confirm recent theories...

  10. Microstructure and corrosion resistance of Ni-based alloy laser coatings with nanosize CeO2 addition

    OpenAIRE

    Hong Zhang, Shi; Xi Li, Ming; Hong Yoon, Jae; Yul Cho, Tong; Zhu He, Yi; Gyu Lee, Chan

    2008-01-01

    Micron-size Ni-base alloy (NBA) powders were mixed with both 1.5 wt.% (hereinafter %) micron-size CeO2 (m-CeO2) and also 1.5% and 3.0% nano-size CeO2 (n- CeO2) powders. These mixtures were coated on low-carbon steel (Q235) by 2.0 kW CO2 laser cladding. The effects on the microstructures, phases and electrochemical corrosion of the coatings upon the addition of m- and n- CeO2 powders to NBA (m- and n- CeO2 /NBA) have been investigated. The results showed that a smooth coating was prep...

  11. Microstructure and corrosion resistance of Ni-based alloy laser coatings with nanosize CeO2 addition

    OpenAIRE

    Shi Hong Zhang et al

    2008-01-01

    Micron-size Ni-base alloy (NBA) powders were mixed with both 1.5 wt.% (hereinafter %) micron-size CeO2 (m-CeO2) and also 1.5% and 3.0% nano-size CeO2 (n- CeO2) powders. These mixtures were coated on low-carbon steel (Q235) by 2.0 kW CO2 laser cladding. The effects on the microstructures, phases and electrochemical corrosion of the coatings upon the addition of m- and n- CeO2 powders to NBA (m- and n- CeO2 /NBA) have been investigated. The results showed that a smooth coating was prepared unde...

  12. Diesel/biodiesel soot oxidation with ceo2 and ceo2-zro2-modified cordierites: a facile way of accounting for their catalytic ability in fuel combustion processes

    Directory of Open Access Journals (Sweden)

    Rodrigo F. Silva

    2011-01-01

    Full Text Available CeO2 and mixed CeO2-ZrO2 nanopowders were synthesized and efficiently deposited onto cordierite substrates, with the evaluation of their morphologic and structural properties through XRD, SEM, and FTIR. The modified substrates were employed as outer heterogeneous catalysts for reducing the soot originated from the diesel and diesel/biodiesel blends incomplete combustion. Their activity was evaluated in a diesel stationary motor, and a comparative analysis of the soot emission was carried out through diffuse reflectance spectroscopy. The analyses have shown that the catalyst-impregnated cordierite samples are very efficient for soot oxidation, being capable of reducing the soot emission in more than 60%.

  13. Estudio comparativo entre los cuerpos silíceos de Bambusa y Guadua Estudio comparativo entre los cuerpos silíceos de Bambusa y Guadua

    Directory of Open Access Journals (Sweden)

    Londoño Ximena

    1991-12-01

    Full Text Available Se realiza un estudio anatómico comparativo de los cuerpos silíceos de la zona costal de la epidermis foliar entre Bambusa y Guadua, analizando 9 especies del género Bambusa y 8 especies del género Guadua. Se concluye que la forma no es un carácter diagnóstico que permita diferenciar los dos géneros mientras que el tamaño de los cuerpos silíceos y su distribución si lo son. An anatomical comparative study of silica bodies between Bambusa and Guadua is done.  Nine species of Bambusa and eight species of Guadua are analized. Size and distribution of the silica bodies rather than form can be used to distinguish both genera.

  14. Synthesis of Mn-doped CeO2 nanorods and their application as ...

    Indian Academy of Sciences (India)

    Mn-doped CeO2; nanorods; humidity sensitivity. 1. Introduction. It is well known that rare earth oxides have been widely used in electronics, magnetic, chemical engineering, and functional materials for their special characteristics. Cerium oxides have been found to be highly interesting materi- als in processes related to the ...

  15. CEOs and CFOs on IPOs: The Process and Success of Going Public

    NARCIS (Netherlands)

    M.J. van den Assem (Martijn); N.L. van der Sar (Nico); P.J.P.M. Versijp (Philippe)

    2017-01-01

    textabstractWe conducted 46 interviews with CEOs and CFOs who were closely involved in an initial public offering (IPO) in the Netherlands. Among other things, we find that pre-existing relationships are a primary consideration in the selection of the lead manager and other syndicate members.

  16. Oxygen Vacancies versus Fluorine at CeO 2 (111) : A Case of Mistaken Identity?

    NARCIS (Netherlands)

    Kullgren, J.; Wolf, M.J.; Castleton, C.W.M.; Mitev, P.; Briels, Willem J.; Hermansson, K.

    2014-01-01

    We propose a resolution to the puzzle presented by the surface defects observed with STM at the (111) surface facet of CeO 2 single crystals. In the seminal paper of Esch et al. [Science 309, 752 (2005)] they were identified with oxygen vacancies, but the observed behavior of these defects is

  17. Scientific team effectiveness and the external CEO: A study of biotechnology university spin-offs

    NARCIS (Netherlands)

    van der Steen, Marianne; Englis-Danskin, Paula; Englis, Basil George

    2013-01-01

    This paper presents an empirical exploration of the effectiveness of scientific teams and the role of an external CEO in the spin-off formation process. The paper contributes to the literature by focusing on the role of the experienced or 'external' entrepreneur (their commercial resources and

  18. The Italian Space Agency Support in the Committee on Earth Observation Satellites (CEOS)

    Science.gov (United States)

    Pisani, Anna Rita; Virelli, Maria; Zoffoli, Simona; Coletta, Alessandro; Candela, Laura Giulia

    2016-08-01

    The Disaster Risk Reduction (DRR) is an important political, economical and societal objective to reduce severe losses and damages caused by natural phenomena or human activity.The Earth Observation (EO) satellites data have been recognised as a useful support for politicians, decision- makers and major stakeholders in all phases of the Disaster Risk Management (DRM).In this framework since 2013 the Committee on Earth Observation Satellites (CEOS) has established the Working Group on Disasters (WG Disasters) to coordinate space agencies efforts in projects focussed on the challenge of the DRR through the EO data exploitation.In order to achieve this purpose CEOS activated three thematic pilot projects (Volcano, Seismic and Flood) and the Recovery Observatory (RO) and supports the Geohazard Supersites and Natural Laboratories (GSNL) initiative of the Group on Earth Observations (GEO). The Italian Space Agency (ASI) participates in CEOS activities since 1986 supporting the GSNL since 2012 and the DRM pilot projects and the RO since the beginning, providing COSMO-SkyMed (CSK) data.In this work recent results achieved by some among the projects in the framework of the CEOS WG Disaster projects, also reported during the last Working Group on Disasters 5th meeting held in Bonn (March 8th-10th, 2016), will be presented, with a focus on the DRM Seismic and Volcano pilots projects (Lefkada earthquake and Cordon Caulle Volcano) and on some Supersites (Hawaii, Bardarbunga and Campi Flegrei).

  19. Spray deposited CeO2–TiO2 counter electrode for electrochromic ...

    Indian Academy of Sciences (India)

    structural, morphological, molecular, optical, electrochromic and colourimetric analysis. CeO2–TiO2 films deposited at 400◦C were ... energy-conserving technology for buildings applications. WO3 thin films have been investigated ... In this contribution, an effort has been taken on the study of structural, morphological, optical ...

  20. Microstructural properties and enhanced photocatalytic performance of Zn doped CeO2nanocrystals.

    Science.gov (United States)

    Khan, M A Majeed; Khan, Wasi; Ahamed, Maqusood; Alhazaa, Abdulaziz N

    2017-10-02

    The microstructural, optical and photocatalytic properties of undoped and 5% Zn doped CeO 2 nanocrystals (NCs) have been explored through various analytical techniques, viz. powder x-ray diffraction (PXRD), x-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), UV-visible, Raman and photoluminescence (PL) spectroscopy. XRD data analysis revealed face centred cubic (FCC) crystal symmetry of the samples with average crystallite size in the range of 19-24 nm. XPS results confirmed that the Zn ions exist in +2 states and successfully incorporated into the CeO 2 matrix. Internal structure and morphology observed by TEM exhibited almost uniform cubical shape of the particles of average size ~20-26 nm. The enegy bandgap of undoped and Zn doped CeO 2 NCs had a direct transition of 3.46 eV and 3.57 eV respectively as estimated by the optical absorption data. The increase in the bandgap revealed blue shift of absorption edge due to the quantum confinement effects. The NCs exhibited an inherent luminescence emission peak at ~408 nm in PL spectra. Improvement in the photocatalytic activity was observed for Zn incorporated sample attributed to the enhanced light absorption or/and fall in charge recombination rate between CeO 2 and Zn.

  1. The possible role of cerium oxide (CeO 2 ) nanoparticles in ...

    African Journals Online (AJOL)

    Results showed that CeO2NPs resulted in partial neuroprotection against disturbances in motor performance. It also partially decreased apoptosis and oxidative stress in preventive group, while it failed to increase striatal dopamine level as compared to untreated rats. The present study verified some neuroprotective effects ...

  2. Long-term aging of a CeO2 based nanocomposite used for wood protection

    International Nuclear Information System (INIS)

    Auffan, Melanie; Masion, Armand; Labille, Jerome; Diot, Marie-Ange; Liu, Wei; Olivi, Luca; Proux, Olivier; Ziarelli, Fabio; Chaurand, Perrine; Geantet, Christophe; Bottero, Jean-Yves; Rose, Jerome

    2014-01-01

    A multi-scale methodology was used to characterize the long-term behavior and chemical stability of a CeO 2 -based nanocomposite used as UV filter in wood stains. ATR-FTIR and 13 C NMR demonstrated that the citrate coated chelates with Ce(IV) through its central carboxyl- and its α-hydroxyl- groups at the surface of the unaged nanocomposite. After 42 days under artificial daylight, the citrate completely disappeared and small amount of degradation products remained attached to the surface even after 112 days. Moreover, the release/desorption of the citrate layer led to a surface reorganization of the nano-sized CeO 2 core observed by XANES (Ce L 3 -edge). Such a surface and structural transformation of the commercialized nanocomposite could have implications in term of fate, transport, and potential impacts towards the environment. - Highlights: • Organic coating of the nano-composite is degradated after 1.5 month. • Structural reorganization of the nano-sized CeO 2 core over aging. • Potential implications in term of exposure and impact towards biological organisms. - The long-term aging of a CeO 2 nanocomposite lead to surface chemistry and structural changes in aquatic environments

  3. Spray deposited CeO2–TiO2 counter electrode for electrochromic ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 38; Issue 2. Spray deposited ... Yxy and *** coordinates signify CeO2–TiO2 films and it also exhibits the application as counter electrode in electrochromic smart windows in which they are able to retain their transparency under charge insertion/extraction.

  4. Antimicrobial potential of green synthesized CeO2nanoparticles fromOlea europaealeaf extract.

    Science.gov (United States)

    Maqbool, Qaisar; Nazar, Mudassar; Naz, Sania; Hussain, Talib; Jabeen, Nyla; Kausar, Rizwan; Anwaar, Sadaf; Abbas, Fazal; Jan, Tariq

    This article reports the green fabrication of cerium oxide nanoparticles (CeO 2 NPs) using Olea europaea leaf extract and their applications as effective antimicrobial agents. O. europaea leaf extract functions as a chelating agent for reduction of cerium nitrate. The resulting CeO 2 NPs exhibit pure single-face cubic structure, which is examined by X-ray diffraction, with a uniform spherical shape and a mean size 24 nm observed through scanning electron microscopy and transmission electron microscopy. Ultraviolet-visible spectroscopy confirms the characteristic absorption peak of CeO 2 NPs at 315 nm. Fourier transform infrared spectroscopy reflects stretching frequencies at 459 cm -1 , showing utilization of natural components for the production of NPs. Thermal gravimetric analysis predicts the successful capping of CeO 2 NPs by bioactive molecules present in the plant extract. The antimicrobial studies show significant zone of inhibition against bacterial and fungal strains. The higher activities shown by the green synthesized NPs than the plant extract lead to the conclusion that they can be effectively used in biomedical application. Furthermore, reduction of cerium salt by plant extract will reduce environmental impact over chemical synthesis.

  5. Master the Moment Fifty CEOs Teach You the Secrets of Time Management

    CERN Document Server

    Brans, Pat

    2010-01-01

    High achievers are not necessarily smarter or putting in more effort than those around them. But they do have different attitudes and are more careful how they use time. From their perspective they are moving at a comfortable pace. To the typical bystander, they are zipping past. Master The Moment reveals tips from 50 CEOs - all Masters of Time.

  6. Facile synthesis of ferromagnetic Ni doped CeO2 nanoparticles with enhanced anticancer activity

    Science.gov (United States)

    Abbas, Fazal; Jan, Tariq; Iqbal, Javed; Ahmad, Ishaq; Naqvi, M. Sajjad H.; Malik, Maaza

    2015-12-01

    NixCe1-xO2 (where x = 0, 0.01, 0.03, 0.05 and 0.07) nanoparticles were synthesized by soft chemical method and were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman, UV-vis absorption spectroscopy and vibrating sample magnetometer (VSM). XRD and Raman results indicated the formation of single phase cubic fluorite structure for the synthesized nanoparticles. Ni dopant induced excessive structural changes such as decrease in crystallite size as well as lattice constants and enhancement in oxygen vacancies in CeO2 crystal structure. These structural variations significantly influenced the optical and magnetic properties of CeO2 nanoparticles. The synthesized NixCe1-xO2 nanoparticles exhibited room temperature ferromagnetic behavior. Ni doping induced effects on the cytotoxicity of CeO2 nanoparticles were examined against HEK-293 healthy cell line and SH-SY5Y neuroblastoma cancer cell line. The prepared NixCe1-xO2 nanoparticles demonstrated differential cytotoxicity. Furthermore, anticancer activity of CeO2 nanoparticles observed to be significantly enhanced with Ni doping which was found to be strongly correlated with the level of reactive oxygen species (ROS) production. The prepared ferromagnetic NixCe1-xO2 nanoparticles with differential cytotoxic nature may be potential for future targeted cancer therapy.

  7. Scientific Team Effectiveness and the External CEO: A Study of Biotechnology University Spin-Offs

    Science.gov (United States)

    van der Steen, Marianne; Englis, Paula Danskin; Englis, Basil G.

    2013-01-01

    This paper presents an empirical exploration of the effectiveness of scientific teams and the role of an external CEO in the spin-off formation process. The paper contributes to the literature by focusing on the role of the experienced or "external" entrepreneur (their commercial resources and capabilities) in the early phase of spin-off…

  8. CEOs and CFOs on IPOs: The Process and Success of Going Public

    NARCIS (Netherlands)

    van den Assem, M.J.; Van der Sar, N.L.; Versijp, P.

    2017-01-01

    We conducted 46 interviews with CEOs and CFOs who were closely involved in an initial public offering (IPO) in the Netherlands. Among other things, we find that pre-existing relationships are a primary consideration in the selection of the lead manager and other syndicate members. Pre-marketing

  9. Remembering Apple CEO Steve Jobs as a "Transformational Leader": Implications for Pedagogy

    Science.gov (United States)

    Steinwart, Marlane C.; Ziegler, Jennifer A.

    2014-01-01

    This paper explores the implications of using Apple co-founder and former CEO Steve Jobs as a "paradigm case" of transformational leadership by comparing the practical metadiscourse of remembrances published at the time of his passing to the theoretical metadiscourse of transformational leadership. The authors report the frequency of…

  10. What's behind the leadership shift in sustainable development from politicians to CEOs?

    NARCIS (Netherlands)

    Zoeteman, B.C.J.

    2013-01-01

    Leadership in sustainable development has gradually shifted during the past decades, with forward-thinking CEOs of prominent multinational corporations increasingly taking over the role formerly played exclusively by national politicians. This paper discusses possible drivers for a growing divide in

  11. Us Knows Us in the UK : On Director Networks and CEO Compensation

    NARCIS (Netherlands)

    Renneboog, L.D.R.; Zhao, Y.

    2011-01-01

    We analyze the relation between CEO compensation and networks of executive and non-executive directors for all listed UK companies over the period 1996-2007. We examine whether networks are built for reasons of information gathering or for the accumulation of managerial influence. Both indirect

  12. Aqueous and Surface Chemistries of Photocatalytic Fe-Doped CeO2 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Duangdao Channei

    2017-01-01

    Full Text Available The present work describes the effects of water on Fe-doped nanoparticulate CeO2, produced by flame spray pyrolysis, which is a critical environmental issue because CeO2 is not stable in typical atmospheric conditions. It is hygroscopic and absorbs ~29 wt % water in the bulk when exposed to water vapor but, more importantly, it forms a hydrated and passivating surface layer when immersed in liquid water. In the latter case, CeO2 initially undergoes direct and/or reductive dissolution, followed by the establishment of a passivating layer calculated to consist of ~69 mol % solid CeO2·2H2O and ~30 mol % gelled Ce(OH4. Under static flow conditions, a saturated boundary layer also forms but, under turbulent flow conditions, this is removed. While the passivating hydrated surface layer, which is coherent probably owing to the continuous Ce(OH4 gel, would be expected to eliminate the photoactivity, this does not occur. This apparent anomaly is explained by the calculation of (a the thermodynamic stability diagrams for Ce and Fe; (b the speciation diagrams for the Ce4+-H2O, Ce3+-H2O, Fe3+-H2O, and Fe2+-H2O systems; and (c the Pourbaix diagrams for the Ce-H2O and Fe-H2O systems. Furthermore, consideration of the probable effects of the localized chemical and redox equilibria owing to the establishment of a very low pH (<0 at the liquid-solid interface also is important to the interpretation of the phenomena. These factors highlight the critical importance of the establishment of the passivating surface layer and its role in photocatalysis. A model for the mechanism of photocatalysis by the CeO2 component of the hydrated phase CeO2·2H2O is proposed, explaining the observation of the retention of photocatalysis following the apparent alteration of the surface of CeO2 upon hydration. The model involves the generation of charge carriers at the outer surface of the hydrated surface layer, followed by the formation of radicals, which decompose organic

  13. Synthesis of novel CeO2-BiVO4/FAC composites with enhanced visible-light photocatalytic properties.

    Science.gov (United States)

    Zhang, Jin; Wang, Bing; Li, Chuang; Cui, Hao; Zhai, Jianping; Li, Qin

    2014-09-01

    To utilize visible light more effectively in photocatalytic reactions, a fly ash cenosphere (FAC)-supported CeO2-BiVO4 (CeO2-BiVO4/FAC) composite photocatalyst was prepared by modified metalorganic decomposition and impregnation methods. The physical and photophysical properties of the composite have been characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and UV-Visible diffuse reflectance spectra. The XRD patterns exhibited characteristic diffraction peaks of both BiVO4 and CeO2 crystalline phases. The XPS results showed that Ce was present as both Ce(4+) and Ce(3+) oxidation states in CeO2 and dispersed on the surface of BiVO4 to constitute a p-n heterojunction composite. The absorption threshold of the CeO2-BiVO4/FAC composite shifted to a longer wavelength in the UV-Vis absorption spectrum compared to the pure CeO2 and pure BiVO4. The composites exhibited enhanced photocatalytic activity for Methylene Blue (MB) degradation under visible light irradiation. It was found that the 7.5wt.% CeO2-BiVO4/FAC composite showed the highest photocatalytic activity for MB dye wastewater treatment. Copyright © 2014. Published by Elsevier B.V.

  14. Magnetic ordered mesoporous Fe3O4/CeO2 composites with synergy of adsorption and Fenton catalysis

    Science.gov (United States)

    Li, Keyan; Zhao, Yongqin; Song, Chunshan; Guo, Xinwen

    2017-12-01

    Magnetic Fe3O4/CeO2 composites with highly ordered mesoporous structure and large surface area were synthesized by impregnation-calcination method, and the mesoporous CeO2 as support was synthesized via the hard template approach. The composition, morphology and physicochemical properties of the materials were characterized by XRD, SEM, TEM, XPS, Raman spectra and N2 adsorption/desorption analysis. The mesoporous Fe3O4/CeO2 composite played a dual-function role as both adsorbent and Fenton-like catalyst for removal of organic dye. The methylene blue (MB) removal efficiency of mesoporous Fe3O4/CeO2 was much higher than that of irregular porous Fe3O4/CeO2. The superior adsorption ability of mesoporous materials was attributed to the abundant oxygen vacancies on the surface of CeO2, high surface area and ordered mesoporous channels. The good oxidative degradation resulted from high Ce3+ content and the synergistic effect between Fe and Ce. The mesoporous Fe3O4/CeO2 composite presented low metal leaching (iron 0.22 mg L-1 and cerium 0.63 mg L-1), which could be ascribed to the strong metal-support interactions for dispersion and stabilization of Fe species. In addition, the composite can be easily separated from reaction solution with an external magnetic field due to its magnetic property, which is important to its practical applications.

  15. Morphologically controlled synthesis, structural and optical properties of CeO2/SnO2 nanocomposites

    Directory of Open Access Journals (Sweden)

    S. Usharani

    2017-09-01

    Full Text Available CeO2/SnO2 nanocomposites with different dimensional nanostructures were synthesized by a wet chemical method, using various surfactants such as SDS, CTAB and Triton X-100. The prepared CeO2/SnO2 samples were analyzed by X-ray diffraction (XRD, Fourier transform infrared (FTIR, Transmission electron microscopy (TEM, UV-Diffuse Reflectance Spectroscopy (UV-DRS, and Photoluminescence (PL spectroscopy. The XRD patterns reveal the presence of a mixed phase of SnO2 and CeO2; The TEM analysis showed the mixed morphology of uniformly dispersed spherical with ellipsoidal shape in the SDS assisted CeO2/SnO2 nanocomposites; whereas the nanostructure with spherical with hexagonal shapes was observed for the Triton X-100 assisted CeO2/SnO2 nanocomposites. The one dimensional (1D nanorod like structure observed for the CTAB assisted CeO2/SnO2 nanocomposites shows CTAB acting as a face-specific capping agent to form rod-shaped micelles. The room temperature photoluminescence emission studies of the CeO2/SnO2 nanocomposites showed strong peaks in the UV region, and several peaks in the visible region, which are likely to have originated from the oxygen vacancies and are potential materials for optoelectronic device applications. The UV results showed the absorption edges shifted to a high energy region and the blue shifts that occurred in all the samples.

  16. Synthesis, characterization, and ecotoxicity of CeO2 nanoparticles with differing properties

    Science.gov (United States)

    Alam, Bushra; Philippe, Allan; Rosenfeldt, Ricki R.; Seitz, Frank; Dey, Sonal; Bundschuh, Mirco; Schaumann, Gabriele E.; Brenner, Sara A.

    2016-10-01

    CeO2 nanoparticles with various characteristics find an increasing number of applications in the electronic, medical, and other industries and are therefore likely released in the environment. This calls for investigations linking the physicochemical properties of these particles with their potential environmental impacts. In this study, CeO2 nanoparticle powders were prepared using three different precursors [Ce(NO3)3, CeCl3, and Ce(CH3COO)3] and annealing temperatures (300, 500, and 700 °C). This procedure resulted in nine different types of nanoparticles with differing size (5-90 nm), morphology, surface Ce3+/Ce4+ ratio, and slightly different crystal structures as characterized using transmission electron microscopy, dynamic light scattering, X-ray photoelectron spectroscopy, and X-ray diffraction measurements with Rietveld refinement. These CeO2 nanoparticles underwent toxicity testing at concentrations up to 64 mg L-1 using Daphnia magna. Toxic effects were observed for three particle types with EC50 values between 5 and 64 mg L-1. No clear correlation was observed between the physicochemical properties (size, shape, oxygen occupancy, Ce3+/Ce4+ ratio) of the nanoparticles and their toxicity. However, toxicity was correlated with the amount of Ce remaining suspended in the test medium after 24 h. This indicated that toxic effects may depend on the colloidal stability of CeO2 nanoparticles during the first day of exposure. Therefore, being readily suspended and remaining stable for several days in the aquatic media increases the likelihood that CeO2 nanoparticles will cause unwanted adverse effects.

  17. Remote Sensing Education and Development Countries: Multilateral Efforts through the Committee on Earth Observation Satellites (CEOS)

    Science.gov (United States)

    Charles, Leslie Bermann

    1998-01-01

    The Committee on Earth Observation Satellites (CEOS) is an international organization which coordinates space-based Earth observations world wide. Created in 1984, CEOS now comprises 38 national space agencies, regional organizations and international space-related and research groups. The aim of CEOS is to achieve international coordination in the planning of satellite missions for Earth observation and to maximize the utilization of data from these missions world-wide. With regard to developing countries, the fundamental aim of CEOS is to encourage the creation and maintenance of indigenous capability that is integrated into the local decision-making process, thereby enabling developing countries to obtain the maximum benefit from Earth observation. Obtaining adequate access to remote sensing information is difficult for developing countries and students and teachers alike. High unit data prices, the specialized nature of the technology , difficulty in locating specific data, complexities of copyright provisions, the emphasis on "leading edge" technology and research, and the lack of training materials relating to readily understood application are frequently noted obstacles. CEOS has developed an education CD-ROM which is aimed at increasing the integration of space-based data into school curricula, meeting the heretofore unsatisfied needs of developing countries for information about Earth observation application, data sources and future plans; and raising awareness around the world of the value of Earth observation data from space. The CD-ROM is designed to be used with an Internet web browser, increasing the information available to the user, but it can also be used on a stand-alone machine. It contains suggested lesson plans and additional resources for educators and users in developing countries.

  18. Moving forward together? The relational dynamics of family-owners and non-family CEOs in private family firms

    OpenAIRE

    Kelleci, Ruveyda; Lambrechts, Frank; Voordeckers, Wim; Huybrechts, Jolien

    2015-01-01

    When an owner hires a nonfamily CEO, family firm performance is largely dependent on the ability of both actors to form an effective team. This paper aims to examine how the owner and nonfamily CEO come to form an effective team, and the relational dynamics that come in to play in doing so. Using Schein’s helping as a theoretical frame of reference, we view team formation as a relational process between the owner and the nonfamily CEO. Adopting a grounded theory approach, we identify several ...

  19. Implementation Integrity of Practice-Based Coaching: Preliminary Results from the BEST in CLASS Efficacy Trial

    Science.gov (United States)

    Sutherland, Kevin S.; Conroy, Maureen A.; Vo, Abigail; Ladwig, Crystal

    2015-01-01

    The purpose of this article is to describe the practice-based coaching model used in BEST in CLASS, a Tier-2 classroom-based intervention comprised of evidence-based instructional practices designed to prevent and ameliorate the chronic problem behaviors of young children at risk for the development of emotional/behavioral disorders. Following a…

  20. The translocation and distribution of CeO2 nanoparticles in plants (Soybeans, Chili, Eggplant and Tomato)

    Science.gov (United States)

    Li, Teng; Dai, Yanhui

    2018-02-01

    Intensive production of CeO2 nanoparticles (NPs) would lead to their release into the environment. While their use in commercial goods is constantly increasing, location of NPs in plant is still poorly documented. In this study we determined the translocation of CeO2-NPs in four plants (Soybeans, Tomato, Chili and Eggplant) grown in natural conditions. The plants were digged out 1/4 roots into 2000 mg/L CeO2-NPs solution during the blossoming period. After being exposed for one month, the contents of Ce in plant tissues were measured by inductively coupled plasma mass spectrometry (ICP-MS). There was more Ce in the leaf of treated plants than in control plants. The contents of Ce in leaf tissues was different. This research offers vital information about the translocation and distribution of CeO2-NPs in higher plants.

  1. Controlled growth of epitaxial CeO2 thin films with self-organized nanostructure by chemical solution method

    DEFF Research Database (Denmark)

    Yue, Zhao; Grivel, Jean-Claude

    2013-01-01

    a fluorite structure but exhibits an alternative in-plane texture with eight fold symmetry on the surface. According to phase and texture stability studies, these off-stoichiometric phases gradually transform back to fully oxidized CeO2 with a 45° rotated cube texture during storage in ambient air. Moreover......Chemical solution deposition is a versatile technique to grow oxide thin films with self-organized nanostructures. Morphology and crystallographic orientation control of CeO2 thin films grown on technical NiW substrates by a chemical solution deposition method are achieved in this work. Based......, the morphology of the CeO2 thin films is controlled by precisely regulating the film thickness and crystallization temperature. A temperature-induced transition from the commonly observed granular grain to an atomically flat surface is found in the CeO2–NiW constitution. Cross-sectional transmission electron...

  2. Differential genomic effects on signaling pathways by two different CeO2 nanoparticles in HepG2 cells

    Data.gov (United States)

    U.S. Environmental Protection Agency — Differential genomic effects on signaling pathways by two different CeO2 nanoparticles in HepG2 cells. This dataset is associated with the following publication:...

  3. The effect of CO-doped on the room-temperature ferromagnetism of CeO2 nanorods

    Science.gov (United States)

    Xu, H. F.; Li, H.

    2015-03-01

    Co-doped CeO2 nanorods of 10-20 nm in diameter and 200-600 nm or more in length have been synthesized by a simple co-precipitation method. The results of XRD and SADE analysis indicate that the as-synthesized CeO2 samples have the fluorite structure. X-ray photoelectron spectroscopy and Raman spectra show that Ce4+ and Ce3+ ions coexist at the surface of non-doped CeO2 nanorods. The magnetic measurements indicated that Co-doped CeO2 nanorods exhibit stronger ferromagnetism at room temperature, and while increasing the amount of Co ions, the ferromagnetism increase more, which can be associated with the presence of Ce3+ and Co2+.

  4. Microstructure and corrosion resistance of Ni-based alloy laser coatings with nanosize CeO2 addition

    Science.gov (United States)

    Zhang, Shi Hong; Li, Ming Xi; Yoon, Jae Hong; Cho, Tong Yul; Zhu He, Yi; Lee, Chan Gyu

    2008-07-01

    Micron-size Ni-base alloy (NBA) powders were mixed with both 1.5 wt.% (hereinafter %) micron-size CeO2 (m-CeO2) and also 1.5% and 3.0% nano-size CeO2 (n- CeO2) powders. These mixtures were coated on low-carbon steel (Q235) by 2.0 kW CO2 laser cladding. The effects on the microstructures, phases and electrochemical corrosion of the coatings upon the addition of m- and n- CeO2 powders to NBA (m- and n- CeO2 /NBA) have been investigated. The results showed that a smooth coating was prepared under suitable processing parameters (P= 2.0 kW, V= 180 mm min- 1) by adding 1.5% n- CeO2. In addition to the primary phases of γ-Ni, Cr23 C6 and Ni3 B in the Ni-base alloy coating, CeNi3 was formed in Ni-base alloy coatings with both n- CeO2 and m-CeO2 particles, and CeNi5 appeared in the coating upon decreasing the size of CeO2 particles. Well-developed dendrites were observed in the Ni-base alloy coating; directional dendrites grew at the interface in the coating upon the addition of m-CeO2, whereas fine and multioriented dendrites grew upon decreasing the size of CeO2 particles to the nanoscale. Actinomorphic dendrites and compact equiaxed dendrites grew from the interface to near the surface upon increasing the content of n- CeO2 from 1.5 to 3.0%. In strongly acidic HNO3 solution, the severe corrosion of dendrites occurred and there were many corrosion pits in the Ni-base alloy coating; intercrystalline corrosion also has a dominant role upon the addition of m-CeO2, whereas uniform corrosion occurs in the coating as the size of CeO2 particles is decreased to nanoscale.

  5. In vitro skin decontamination of the organophosphorus pesticide Paraoxon with nanometric cerium oxide CeO2.

    Science.gov (United States)

    Salerno, Alicia; Devers, Thierry; Bolzinger, Marie-Alexandrine; Pelletier, Jocelyne; Josse, Denis; Briançon, Stéphanie

    2017-04-01

    Organophosphorus compounds (OP), which mainly penetrate via the percutaneous pathway, represent a threat for both military and civilians. Body surface decontamination is vital to prevent victims poisoning. The development of a cost-effective formulation, which could be efficient and easy to handle in case of mass contamination, is therefore crucial. Metal oxides nanoparticles, due their large surface areas and the large amount of highly reactive sites, present high reactivity towards OP. First, this study aimed at evaluating the reaction of CeO 2 nanoparticles, synthetized by microwave path and calcined at 500 or 600 °C, with Paraoxon (POX) in aqueous solution. Results showed that both nanoparticles degraded 60%-70% of POX. CeO 2 calcined at 500 °C, owing to its larger specific area, was the most effective. Moreover, the degradation was significantly increased under Ultra-Violet irradiation (initial degradation rate doubled). Then, skin decontamination was studied in vitro using the Franz cell method with pig-ear skin samples. CeO 2 powder and an aqueous suspension of CeO 2 (CeO 2 -W) were applied 1 h after POX exposure. The efficiency of decontamination, including removal and/or degradation of POX, was compared to Fuller's earth (FE) and RSDL lotion which are, currently, the most efficient systems for skin decontamination. CeO 2 -W and RSDL were the most efficient to remove POX from the skin surface and decrease skin absorption by 6.4 compared to the control not decontaminated. FE reduced significantly (twice) the absorbed fraction of POX, contrarily to CeO 2 powder. Considering only the degradation rate of POX, the products ranged in the order CeO 2  > RSDL > CeO 2 -W > FE (no degradation). This study showed that CeO 2 nanoparticles are a promising material for skin decontamination of OP if formulated as a dispersion able to remove POX like CeO 2 -W and to degrade it as CeO 2 powder. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. Microstructure and corrosion resistance of Ni-based alloy laser coatings with nanosize CeO2 addition

    Directory of Open Access Journals (Sweden)

    Shi Hong Zhang et al

    2008-01-01

    Full Text Available Micron-size Ni-base alloy (NBA powders were mixed with both 1.5 wt.% (hereinafter % micron-size CeO2 (m-CeO2 and also 1.5% and 3.0% nano-size CeO2 (n- CeO2 powders. These mixtures were coated on low-carbon steel (Q235 by 2.0 kW CO2 laser cladding. The effects on the microstructures, phases and electrochemical corrosion of the coatings upon the addition of m- and n- CeO2 powders to NBA (m- and n- CeO2 /NBA have been investigated. The results showed that a smooth coating was prepared under suitable processing parameters (P= 2.0 kW, V= 180 mm min- 1 by adding 1.5% n- CeO2. In addition to the primary phases of γ-Ni, Cr23 C6 and Ni3 B in the Ni-base alloy coating, CeNi3 was formed in Ni-base alloy coatings with both n- CeO2 and m-CeO2 particles, and CeNi5 appeared in the coating upon decreasing the size of CeO2 particles. Well-developed dendrites were observed in the Ni-base alloy coating; directional dendrites grew at the interface in the coating upon the addition of m-CeO2, whereas fine and multioriented dendrites grew upon decreasing the size of CeO2 particles to the nanoscale. Actinomorphic dendrites and compact equiaxed dendrites grew from the interface to near the surface upon increasing the content of n- CeO2 from 1.5 to 3.0%. In strongly acidic HNO3 solution, the severe corrosion of dendrites occurred and there were many corrosion pits in the Ni-base alloy coating; intercrystalline corrosion also has a dominant role upon the addition of m-CeO2, whereas uniform corrosion occurs in the coating as the size of CeO2 particles is decreased to nanoscale.

  7. Integration of atomic layer deposition CeO2 thin films with functional complex oxides and 3D patterns

    International Nuclear Information System (INIS)

    Coll, M.; Palau, A.; Gonzalez-Rosillo, J.C.; Gazquez, J.; Obradors, X.; Puig, T.

    2014-01-01

    We present a low-temperature, < 300 °C, ex-situ integration of atomic layer deposition (ALD) ultrathin CeO 2 layers (3 to 5 unit cells) with chemical solution deposited La 0.7 Sr 0.3 MnO 3 (LSMO) functional complex oxides for multilayer growth without jeopardizing the morphology, microstructure and physical properties of the functional oxide layer. We have also extended this procedure to pulsed laser deposited YBa 2 Cu 3 O 7 (YBCO) thin films. Scanning force microscopy, X-ray diffraction, aberration corrected scanning transmission electron microscopy and macroscopic magnetic measurements were used to evaluate the quality of the perovskite films before and after the ALD process. By means of microcontact printing and ALD we have prepared CeO 2 patterns using an ozone-robust photoresist that will avoid the use of hazardous lithography processes directly on the device components. These bilayers, CeO 2 /LSMO and CeO 2 /YBCO, are foreseen to have special interest for resistive switching phenomena in resistive random-access memory. - Highlights: • Integration of atomic layer deposition (ALD) CeO 2 layers on functional complex oxides • Resistive switching is identified in CeO 2 /La 0.7 Sr 0.3 MnO 3 and CeO 2 /YBa 2 Cu 3 O 7 bilayers. • Study of the robustness of organic polymers for area-selective ALD • Combination of ALD and micro-contact printing to obtain 3D patterns of CeO 2

  8. Thermal properties of plasma sprayed CeO2-ZrO2-Y2O3

    International Nuclear Information System (INIS)

    Suzuki, T.; Takeda, H.; Itoh, M.; Takahashi, Y.

    1985-01-01

    Thermal Barrier Coatings, TBC, has been developed as an effective procedure to increase the efficiency of a cooling system used in high temperature machine parts. Usually, TBC consists of a metal bond coat and a ceramic overcoat formed by plasma spraying. Y 2 O 3 stabilized ZrO 2 is conventional for the ceramic overcoat, since thermal conductivity and thermal expansion are critical properties for TBC ceramic layer. In this view, CeO 2 is unstable at high temperature. To apply CeO 2 properly, combination with stable ZrO 2 -Y 2 O 3 system is proposed. Then thermal properties of plasma properties of plasma sprayed CeO 2 -ZrO 2 -Y 2 O 3 layer were investigated. Thermal conductivity of CeO 2 -ZrO 2 -Y 2 O 3 is lower, and thermal expansion coefficient of CeO 2 -ZrO 2 -Y 2 O 3 is larger than those of ZrO 2 -Y 2 O 3 . From this investigation, the authors showed a possibility of plasma sprayed CeO 2 -ZrO 2 -Y 2 O 3 TBC superior to ZrO 2 -Y 2 O 3 TBC

  9. Fate and Phytotoxicity of CeO2 Nanoparticles on Lettuce Cultured in the Potting Soil Environment.

    Directory of Open Access Journals (Sweden)

    Xin Gui

    Full Text Available Cerium oxide nanoparticles (CeO2 NPs have been shown to have significant interactions in plants. Previous study reported the specific-species phytotoxicity of CeO2 NPs by lettuce (Lactuca sativa, but their physiological impacts and vivo biotransformation are not yet well understood, especially in relative realistic environment. Butterhead lettuce were germinated and grown in potting soil for 30 days cultivation with treatments of 0, 50, 100, 1000 mg CeO2 NPs per kg soil. Results showed that lettuce in 100 mg·kg-1 treated groups grew significantly faster than others, but significantly increased nitrate content. The lower concentrations treatment had no impact on plant growth, compared with the control. However, the higher concentration treatment significantly deterred plant growth and biomass production. The stress response of lettuce plants, such as Superoxide dismutase (SOD, Peroxidase (POD, Malondialdehyde(MDA activity was disrupted by 1000 mg·kg-1 CeO2 NPs treatment. In addition, the presence of Ce (III in the roots of butterhead lettuce explained the reason of CeO2 NPs phytotoxicity. These findings demonstrate CeO2 NPs modification of nutritional quality, antioxidant defense system, the possible transfer into the food chain and biotransformation in vivo.

  10. A face only an investor could love: CEOs' facial structure predicts their firms' financial performance.

    Science.gov (United States)

    Wong, Elaine M; Ormiston, Margaret E; Haselhuhn, Michael P

    2011-12-01

    Researchers have theorized that innate personal traits are related to leadership success. Although links between psychological characteristics and leadership success have been well established, research has yet to identify any objective physical traits of leaders that predict organizational performance. In the research reported here, we identified leaders' facial structure as a specific physical trait that correlates with organizational performance. Specifically, we found that firms whose male CEOs have wider faces (relative to facial height) achieve superior financial performance. Decision-making dynamics within a firm's leadership team moderate this effect, such that the relationship between a given CEO's facial measurements and his firm's financial performance is stronger in firms with cognitively simple leadership teams.

  11. Raman scattering study of the anharmonic effects in CeO2-y nanocrystals

    Science.gov (United States)

    Popović, Z. V.; Dohčević-Mitrović, Z.; Cros, A.; Cantarero, A.

    2007-12-01

    We have studied the temperature dependence of the F2g Raman mode phonon frequency and broadening in CeO2-y nanocrystals. The phonon softening and phonon linewidth are calculated using a model which takes into account the three-and four-phonon anharmonic processes. A detailed comparison of the experimental data with theoretical calculations revealed the predominance of four-phonon anharmonic processes in the temperature dependence of the phonon energy and broadening of the nanocrystals. On the other hand, three-phonon processes dominate the temperature behavior of phonons in polycrystalline samples. The anti-Stokes/Stokes peak intensity ratio was also investigated and found to be smaller for nanosized CeO2 powders than in the bulk counterpart.

  12. Raman scattering study of the anharmonic effects in CeO2-y nanocrystals

    International Nuclear Information System (INIS)

    Popovic, Z V; Dohcevic-Mitrovic, Z; Cros, A; Cantarero, A

    2007-01-01

    We have studied the temperature dependence of the F 2g Raman mode phonon frequency and broadening in CeO 2-y nanocrystals. The phonon softening and phonon linewidth are calculated using a model which takes into account the three-and four-phonon anharmonic processes. A detailed comparison of the experimental data with theoretical calculations revealed the predominance of four-phonon anharmonic processes in the temperature dependence of the phonon energy and broadening of the nanocrystals. On the other hand, three-phonon processes dominate the temperature behavior of phonons in polycrystalline samples. The anti-Stokes/Stokes peak intensity ratio was also investigated and found to be smaller for nanosized CeO 2 powders than in the bulk counterpart

  13. Development of La3+ Doped CeO2 Thick Film Humidity Sensors

    Directory of Open Access Journals (Sweden)

    Chunjie Wang

    2014-01-01

    Full Text Available The humidity sensitive characteristics of the sensor fabricated from 10 mol% La2O3 doped CeO2 nanopowders with particle size 17.26 nm synthesized via hydrothermal method were investigated at different frequencies. It was found that the sensor shows high humidity sensitivity, rapid response-recovery characteristics, and narrow hysteresis loop at 100 Hz in the relative humidity range from 11% to 95%. The impedance of the sensor decreases by about five orders of magnitude as relative humidity increases. The maximum humidity hysteresis is about 6% RH, and the response and recovery time is 12 and 13 s, respectively. These results indicate that the nanosized La2O3 doped CeO2 powder has potential application as high-performance humidity sensor.

  14. Mn3O4-CeO2 nano-catalysts: Synthesis, characterization and application

    Science.gov (United States)

    Anushree, Sharma, C.; Kumar, S.

    2016-05-01

    Nano-sized Mn3O4-CeO2 catalysts were synthesized by a cost effective co-precipitation method, and were studied as a heterogeneous catalyst for wet air oxidation of paper industry wastewater at mild operating conditions of 90 °C and 1 atm. The structural, micro-structural and textural properties of synthesized catalysts were studied through various characterization techniques, i.e. XRD, TEM, N2-sorption and EDS. The catalytic activity of Mn3O4-CeO2 was interestingly found to be higher than the corresponding single-metal oxides, and the Ce50Mn50 nano-catalyst with small crystallite size (4.5 nm), high specific surface area (75 m2g-1) and high porosity (0.24 ccg-1) was found to be most efficient with 69% color, 60% COD, 59% TOC, 48% AOX removal.

  15. Synthesis and characterization of Sr2CeO4: Eu3+ phosphor by different forms

    International Nuclear Information System (INIS)

    Murthy, K.V.R.; Rao, Ch. Atchyutha; Suresh, K.; Ratna Kumar, B.W.; Nageswara Rao, B.; Poornachandra Rao, N.V.; Subba Rao, B.

    2011-01-01

    High temperature solid state reaction method was explored to synthesize undoped Sr 2 CeO 4 and Eu 3+ RE doped Sr 2 CeO 4 phosphor using inorganic materials taking in three different forms like, form (i) Strontium Carbonate (SrCO 3 ), Cerium Oxide (CeO 2 ), (ii) Strontium Nitrate (Sr(NO 3 ) 2 ), Cerium Oxide (CeO 2 ) and (iii) Strontium Nitrate (Sr(NO 3 ) 2 ), Cerium Nitrate (Ce(NO 3 ) 3 .6(NH 2 .CO.NH 2 ) in stoichiometric proportions of Sr:Ce as 2:1 and ground into a fine powder using agate mortar and pestle about an hour. The grounded samples were placed in an alumina crucible and fired at 1200 deg C for 3 hours in a muffle furnace with a heating rate of 5 deg C/min. To investigate the crystal structure, phase, morphology and luminescent properties of the synthesized phosphors XRD, SEM, Photoluminescence (PL) spectra, TL and CIE techniques were used. The Photoluminescence (PL) emission and excitation spectra were measured by Spectrofluorophotometer (SHIMADZU, RF-5301 PC) using Xenon lamp as excitation source. To identify the crystal phase, XRD analysis was carried out with a powder diffractometer (Rigaku-D/max 2500) using CuKα radiation. The microstructures of the samples were studied using a scanning electron microscopy (SEM) (XL 30 CP Philips). All the analysis was recorded at room temperature. We have compared the results of the prepared samples by different forms. From the XRD analysis it was found that the prepared phosphors are mostly in single phase of Sr 2 CeO 4 with an orthorhombic structure. From the XRD data, using Scherrer's formula the calculated average crystallite size is (i) ∼ 28 nm (ii) ∼ 9 nm (iii) ∼ 7 nm using FWHM. This indicates that, the prepared phosphors via high temperature solid state reaction method is in nano size. Sr 2 CeO 4 exhibits photoluminescence due to the charge transfer (CT) mechanism. The sample displays a broad excitation spectrum range from ∼ 220 to 400 nm. Under 350 nm excitation, the undoped Sr 2 CeO 4 shows

  16. Room temperature synthesis and enhanced photocatalytic property of CeO2/ZnO heterostructures

    Science.gov (United States)

    Wang, Chao; Fan, Huiqing; Ren, Xiaohu; Fang, Jiawen

    2018-02-01

    To achieve better photocatalytic performance, we proposed a facile solid-state reaction method to produce CeO2/ZnO heterostructures. Ceria and zinc oxide were synthesized simultaneously by thoroughly grinding the mixture of zinc acetate dihydrate, cerium nitrate hexahydrate and sodium hydroxide. The morphology of the as-prepared heterostructures varies dramatically as different amount of ceria was introduced in the composition. The photocatalytic performance of CeO2/ZnO heterojunctions was 4.6 times higher than that of pure ZnO. The enhanced photocatalytic activity could be ascribed to that more electrons and holes could transport to the surface of catalysts and react with the pollution due to the extended light-responsive range, accelerated migration, increased specific surface area and suppressed recombination of photogenerated carriers.

  17. Initial sintering stage kinetics of CeO2 studied by stepwise isothermal dilatometry

    International Nuclear Information System (INIS)

    El Sayed Ali, M.; Toft Soerensen, O.

    1985-02-01

    The kinetics of the initial sintering stage of CeO 2 is studied by a new dilatometric technique in which the heating of the sample is controlled by its shrinkage rate. By this technique the shrinkage characteristically takes place in 'isothermal steps' which allows both the mechanism and its activation energy to be determined in a single experiment. The basic equations necessary to evaluate the shrinkage data are described, and using these equations on the curves recorded for CeO 2 it it shown that the controlling mechanism for the initial sintering stage for this oxides is grain-boundary diffusion of Ce 4+ -ions with an activation energy of 119.4 kcal/mole (5.2 eV). The corresponding diffusion coefficient is estimated to vary between 8.5 x 10 -17 - 3.1 x 10 -15 cm 2 /sec (1005 - 1099sup(o)C). (author)

  18. Erosion-Corrosion Property of CeO2-Modified HVOF WC-Co Coating

    Science.gov (United States)

    Liu, Yan; Hang, Zongqiu; Chen, Hui; Ceng, Shengbo; Gou, Guoqing; Wang, Xiaomin; Tu, Mingjing; Wu, Xiangyang

    2016-04-01

    Rare-earth elements have been widely used in materials manufacturing to improve hardness and toughness. In this work, conventional, nanostructured, and CeO2-modified WC-12Co powders were sprayed using high-velocity oxygen flame spraying. The erosion-corrosion behavior and interaction of erosion and corrosion of the coatings in 3.5 wt.% NaCl solution were investigated. In situ observation was employed to analyze the failure mechanism. The results showed that the CeO2-modified WC-12Co coating possessed the best erosion-corrosion resistance, while the lowest corrosion resistance was exhibited by the conventional WC-12Co coating. The results also suggested that the erosion-corrosion mechanism in the three coatings was dominated by corrosion-accelerated erosion. However, the extent of acceleration of erosion by corrosion differed.

  19. Spray deposited CeO2–TiO2 counter electrode for electrochromic ...

    Indian Academy of Sciences (India)

    Abstract. Optically passive thin films of CeO2–TiO2 mixed oxides with molar ratio of Ce/Ti of 0.05 were deposited by the spray pyrolysis technique (SPT) on a glass and fluorine-doped tin oxide (FTO)-coated glass substrates. Precur- sor solution containing cerium nitrate hexahydrate (Ce(NO3)2·6H2O) and titanium ...

  20. The views of American Multinational CEOs on Internationalized Business Education for Prospective Employees

    OpenAIRE

    Donald A Ball; Wendell H McCulloch

    1993-01-01

    For some time, a number of industry leaders have been exhorting American business schools to train their students in the aspects of international business. As late as 1987, a group of prominent leaders from business, labor, academia and government issued a report that stated that business schools must internationalize the entire course of study and should include comparative business practices, foreign languages and analyses of other countries and cultures.But do the CEOs of the major America...

  1. Hospital strategic planning diversity integration based organizational type and CEO tenure.

    Science.gov (United States)

    Newhouse, John J

    2007-01-01

    The author investigated the strategic planning processes used by five different hospital types to integrate diversity practices into their operations. Chief executive officers from Delaware, New Jersey, New York, and Pennsylvania were surveyed to examine how their hospitals used strategic planning in this process. The central research question was: Does this process vary on the basis of hospital type? The findings indicated that some differences do exist by hospital type, as well as the length of tenure for CEOs in their positions.

  2. Electrochemical and optical properties of CeO2-SnO2 and CeO2-SnO2:X (X = Li, C, Si films

    Directory of Open Access Journals (Sweden)

    Berton Marcos A.C.

    2001-01-01

    Full Text Available Thin solid films of CeO2-SnO2 (17 mol% Sn and CeO2-SnO2:X (X = Li, C and Si were prepared by the sol-gel route, using an aqueous-based process. The addition of Li, C and Si to the precursor solution leads to films with different electrochemical performances. The films were deposited by the dip-coating technique on ITO coated glass (Donnelly Glass at a speed of 10 cm/min and submitted to a final thermal treatment at 450 °C during 10 min in air. The electrochemical and optical properties of the films were determined from the cyclic voltammetry and chronoamperometry measurements using 0.1 M LiOH as supporting electrolyte. The ion storage capacity of the films was investigated using in situ spectroelectrochemical method and during the insertion/extraction process the films remained transparent. The powders were characterized by thermal analysis (DSC/TGA and X-ray diffraction.

  3. Ceo2 Based Catalysts for the Treatment of Propylene in Motorcycle’s Exhaust Gases

    Science.gov (United States)

    Pham, Phuong Thi Mai; Le Minh, Thang; Nguyen, Tien The; Van Driessche, Isabel

    2014-01-01

    In this work, the catalytic activities of several single metallic oxides were studied for the treatment of propylene, a component in motorcycles’ exhaust gases, under oxygen deficient conditions. Amongst them, CeO2 is one of the materials that exhibit the highest activity for the oxidation of C3H6. Therefore, several mixtures of CeO2 with other oxides (SnO2, ZrO2, Co3O4) were tested to investigate the changes in catalytic activity (both propylene conversion and CO2 selectivity). Ce0.9Zr0.1O2, Ce0.8Zr0.2O2 solid solutions and the mixtures of CeO2 and Co3O4 was shown to exhibit the highest propylene conversion and CO2 selectivity. They also exhibited good activities when tested under oxygen sufficient and excess conditions and with the presence of co-existing gases (CO, H2O). PMID:28788253

  4. Ceo2 Based Catalysts for the Treatment of Propylene in Motorcycle’s Exhaust Gases

    Directory of Open Access Journals (Sweden)

    Phuong Thi Mai Pham

    2014-11-01

    Full Text Available In this work, the catalytic activities of several single metallic oxides were studied for the treatment of propylene, a component in motorcycles’ exhaust gases, under oxygen deficient conditions. Amongst them, CeO2 is one of the materials that exhibit the highest activity for the oxidation of C3H6. Therefore, several mixtures of CeO2 with other oxides (SnO2, ZrO2, Co3O4 were tested to investigate the changes in catalytic activity (both propylene conversion and CO2 selectivity. Ce0.9Zr0.1O2, Ce0.8Zr0.2O2 solid solutions and the mixtures of CeO2 and Co3O4 was shown to exhibit the highest propylene conversion and CO2 selectivity. They also exhibited good activities when tested under oxygen sufficient and excess conditions and with the presence of co-existing gases (CO, H2O.

  5. Synthesis, Characterization and Properties of CeO2-doped TiO2 Composite Nanocrystals

    Directory of Open Access Journals (Sweden)

    Oman ZUAS

    2013-12-01

    Full Text Available Pure TiO2 and CeO2-doped TiO2 (3 % CeO2-97 %TiO2 composite nanocrystals were synthesized via co-precipitation method and characterized using TGA, XRD, FTIR, DR-UV-vis and TEM. The XRD data revealed that the phase structure of the synthesized samples was mainly in pure anatase having crystallite size in the range of 7 nm – 11 nm. Spherical shapes with moderate aggregation of the crystal particles were observed under the TEM observation. The presence of the CeO2 at TiO2 site has not only affected morphologically but also induced the electronic property of the TiO2 by lowering the band gap energy from 3.29 eV (Eg-Ti to 3.15 eV (Eg-CeTi. Performance evaluation of the synthesized samples showed that both samples have a strong adsorption capacity toward Congo red (CR dye in aqueous solution at room temperature experiment, where  the capacity of the CeTi was higher than the Ti sample. Based on DR-UV data, the synthesized samples obtained in this study may also become promising catalysts for photo-assisted removal of synthetic dye in aqueous solution. DOI: http://dx.doi.org/10.5755/j01.ms.19.4.2732

  6. CEO Emoluments Determination of Non Governmental Organisations (NGO in Melaka: A Concept Paper

    Directory of Open Access Journals (Sweden)

    Hassan Masita

    2017-01-01

    Full Text Available Non-governmental organisations (NGOs are formed by mutual members in conducting activities to enhance social welfare of its members and public. The issue of governance of NGO arises when such social welfare fail to be achieved. Principal-agent theory explains that agent (elected CEO or key committees is responsible to carry out NGO activities aligned with principal’s interest (which described in NGO missions and goals. If CEO or key committees are being paid to govern NGO, emolument is primarily perceived as a signal to level of governance of NGO. This study objectively to determine factors that influence the decision of emoluments paid to elected CEO or key committees. Subsequently, this study is to analyze the level of governance of NGO. NGO registered in Melaka will be selected from Registrar of Societies (ROS in Melaka. Therefore, data for this study will be collected using data from ROS Melaka. 594 registered NGO that located in Melaka will be contacted and interviewed to complete structured questionnaire. Data collected will be analyzed using SPSS software to determine the factors that influences emolument decision. Subsequently, data will be analyzed to determine the level of governance of NGOs in Malaysia, which related to emoluments decision making.

  7. Gender bias in hospital leadership: a qualitative study on the experiences of women CEOs.

    Science.gov (United States)

    Soklaridis, Sophie; Kuper, Ayelet; Whitehead, Cynthia R; Ferguson, Genevieve; Taylor, Valerie H; Zahn, Catherine

    2017-04-10

    Purpose The purpose of this paper is to examine the experiences of gender bias among women hospital CEOs and explore to what these female leaders attribute their success within a male-dominated hospital executive leadership milieu. Design/methodology/approach This qualitative study involved 12 women hospital CEOs from across Ontario, Canada. Purposeful sampling techniques and in-depth qualitative interview methods were used to facilitate discussion around experiences of gender and leadership. Findings Responses fell into two groups: the first group represented the statement "Gender inequality is alive and well". The second group reflected the statement "Gender inequity is not significant, did not happen to me, and things are better now". This group contained a sub-group with no consciousness of systemic discrimination and that claimed having no gendered experiences in their leadership journey. The first group described gender issues in various contexts, from the individual to the systemic. The second group was ambivalent about gender as a factor impacting leadership trajectories. Originality/value Representations of women's leadership have become detached from feminism, with major consequences for women. This study reveals how difficult it is for some women CEOs to identify gender bias. The subtle everyday norms and practices within the workplace make it difficult to name and explain gender bias explicitly and may explain the challenges in understanding how it might affect a woman's career path.

  8. Controlled synthesis of CeO2 nanoparticles using novel amphiphilic cerium complex precursors

    International Nuclear Information System (INIS)

    Yan Bing; Zhu Hongxia

    2008-01-01

    Maleic anhydride was grafted by long-chain alcohols (1-hexadecanol, 1-octadecanol) to amphiphilic mono-L cis-butene dicarboxylates (L = hexadecyl, octadecyl), i.e., MAH, MAO, respectively. Subsequently, corresponding amphiphilic cerium complexes with these two mono-L cis-butene dicarboxylate ligands (Ce(L') 3 , L'= MAH, MAO) were synthesized and behaved as the precursors to prepare CeO 2 nanoparticles for both of which can form nanosized micelle-like aggregates by special self-assembly in the wet chemical process. The nanoparticles were further characterized by Fourier transform-infrared spectroscopy (FTIR), Diffuse reflectance ultraviolet-visible spectra (DRUVS), scanning electron microscope (SEM), transmission electron microscope (TEM), and x-ray diffraction (XRD). Both the CeO 2 nanoparticles are in a cubic fluorite structure and present regular and well-dispersion club-like morphology with average particle size in the range of 40-70 nm. Besides, the strong ultraviolet-visible absorption for these CeO 2 nanoparticles can be found at the long-wavelength ultraviolet to visible region of 200-500 nm.

  9. Synthesis of CeO2-based core/shell nanoparticles with high oxygen storage capacity

    Science.gov (United States)

    Uzunoglu, Aytekin; Kose, Dursun Ali; Stanciu, Lia A.

    2017-07-01

    Ceria plays a key role in various applications including sensing and catalysis owing to its high oxygen storage capacity (OSC). The aim of this work is to prepare novel MO x /CeO2 (M: Zr, Ti, Cu) metal oxide systems with core/shell structures using a facile two-step chemical precipitation method. The synthesized nanoparticles were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and N2 adsorption methods. The OSC property of the samples was evaluated using TGA analysis conducted at 600 °C under reductive (5% H2/Ar) and oxidative (synthetic air) environments. The OSCs of the samples were found to be 130, 253, and 2098 µmol-O2/g for ZrO2/CeO2, TiO2/CeO2, and CuO/CeO2, respectively. Effects of heat treatment on the physical and redox properties of the samples were also evaluated. In this regard, the samples were exposed to 500 °C for 5 h under ambient environment. It was observed that the heat treatment induced the formation of mixed metal oxide alloys and the BET surface area of the samples diminished significantly. The OSC of the samples, however, did not experience any significant chance, which was attributed to the compensation of the loss in the surface area by the alloy formation after the heat treatment.

  10. CEOS Theory: A Comprehensive Approach to Understanding Hard to Maintain Behaviour Change.

    Science.gov (United States)

    Borland, Ron

    2017-03-01

    This paper provides a brief introduction to CEOS theory, a comprehensive theory for understanding hard to maintain behaviour change. The name CEOS is an acronym for Context, Executive, and Operational Systems theory. Behaviour is theorised to be the result of the moment by moment interaction between internal needs (operational processes) in relation to environmental conditions, and for humans this is augmented by goal-directed, executive action which can transcend immediate contingencies. All behaviour is generated by operational processes. Goal-directed behaviours only triumph over contingency-generated competing behaviours when operational processes have been sufficiently activated to support them. Affective force can be generated around executive system (ES) goals from such things as memories of direct experience, vicarious experience, and emotionally charged communications mediated through stories the person generates. This paper makes some refinements and elaborations of the theory, particularly around the role of feelings, and of the importance of stories and scripts for facilitating executive action. It also sketches out how it reconceptualises a range of issues relevant to behaviour change. CEOS provides a framework for understanding the limitations of both informational and environmental approaches to behaviour change, the need for self-regulatory strategies and for taking into account more basic aspects of human functioning. © 2016 The Authors. Applied Psychology: Health and Well-Being published by John Wiley & Sons Ltd on behalf of International Association of Applied Psychology.

  11. CEOS contributions to informing energy management and policy decision making using space-based Earth observations

    International Nuclear Information System (INIS)

    Eckman, Richard S.; Stackhouse, Paul W.

    2012-01-01

    Earth observations are playing an increasingly significant role in informing decision making in the energy sector. In renewable energy applications, space-based observations now routinely augment sparse ground-based observations used as input for renewable energy resource assessment applications. As one of the nine Group on Earth Observations (GEO) societal benefit areas, the enhancement of management and policy decision making in the energy sector is receiving attention in activities conducted by the Committee on Earth Observation Satellites (CEOS). CEOS has become the “space arm” for the implementation of the Global Earth Observation System of Systems (GEOSS) vision. It is directly supporting the space-based, near-term tasks articulated in the GEO three-year work plan. This paper describes a coordinated program of demonstration projects conducted by CEOS member agencies and partners to utilize Earth observations to enhance energy management end-user decision support systems. We discuss the importance of engagement with stakeholders and understanding their decision support needs in successfully increasing the uptake of Earth observation products for societal benefit. Several case studies are presented, demonstrating the importance of providing data sets in formats and units familiar and immediately usable by decision makers. These projects show the utility of Earth observations to enhance renewable energy resource assessment in the developing world, forecast space weather impacts on the power grid, and improve energy efficiency in the built environment.

  12. The bright-side and the dark-side of CEO personality: examining core self-evaluations, narcissism, transformational leadership, and strategic influence.

    Science.gov (United States)

    Resick, Christian J; Whitman, Daniel S; Weingarden, Steven M; Hiller, Nathan J

    2009-11-01

    This article reports on an examination of the relationships between chief executive officer (CEO) personality, transformational and transactional leadership, and multiple strategic outcomes in a sample of 75 CEOs of Major League Baseball organizations over a 100-year period. CEO bright-side personality characteristics (core self-evaluations) were positively related to transformational leadership, whereas dark-side personality characteristics (narcissism) of CEOs were negatively related to contingent reward leadership. In turn, CEO transformational and contingent reward leadership were related to 4 different strategic outcomes, including manager turnover, team winning percentage, fan attendance, and an independent rating of influence. CEO transformational leadership was positively related to ratings of influence, team winning percentage, and fan attendance, whereas contingent reward leadership was negatively related to manager turnover and ratings of influence.

  13. Fabrication of CeO2–MOx (M = Cu, Co, Ni composite yolk–shell nanospheres with enhanced catalytic properties for CO oxidation

    Directory of Open Access Journals (Sweden)

    Ling Liu

    2017-11-01

    Full Text Available CeO2–MOx (M = Cu, Co, Ni composite yolk–shell nanospheres with uniform size were fabricated by a general wet-chemical approach. It involved a non-equilibrium heat-treatment of Ce coordination polymer colloidal spheres (Ce-CPCSs with a proper heating rate to produce CeO2 yolk–shell nanospheres, followed by a solvothermal treatment of as-synthesized CeO2 with M(CH3COO2 in ethanol solution. During the solvothermal process, highly dispersed MOx species were decorated on the surface of CeO2 yolk–shell nanospheres to form CeO2–MOx composites. As a CO oxidation catalyst, the CeO2–MOx composite yolk–shell nanospheres showed strikingly higher catalytic activity than naked CeO2 due to the strong synergistic interaction at the interface sites between MOx and CeO2. Cycling tests demonstrate the good cycle stability of these yolk–shell nanospheres. The initial concentration of M(CH3COO2·xH2O in the synthesis process played a significant role in catalytic performance for CO oxidation. Impressively, complete CO conversion as reached at a relatively low temperature of 145 °C over the CeO2–CuOx-2 sample. Furthermore, the CeO2–CuOx catalyst is more active than the CeO2–CoOx and CeO2–NiO catalysts, indicating that the catalytic activity is correlates with the metal oxide. Additionally, this versatile synthesis approach can be expected to create other ceria-based composite oxide systems with various structures for a broad range of technical applications.

  14. Interchange core/shell assembly of diluted magnetic semiconductor CeO2 and ferromagnetic ferrite Fe3O4 for microwave absorption

    Directory of Open Access Journals (Sweden)

    Jiaheng Wang

    2017-05-01

    Full Text Available Core/shell-structured CeO2/Fe3O4 and Fe3O4/CeO2 nanocapsules are prepared by interchange assembly of diluted magnetic semiconductor CeO2 and ferromagnetic ferrite Fe3O4 as the core and the shell, and vice versa, using a facile two-step polar solvothermal method in order to utilize the room-temperature ferromagnetism and abundant O-vacancies in CeO2, the large natural resonance in Fe3O4, and the O-vacancy-enhanced interfacial polarization between CeO2 and Fe3O4 for new generation microwave absorbers. Comparing to Fe3O4/CeO2 nanocapsules, the CeO2/Fe3O4 nanocapsules show an improved real permittivity of 3–10% and an enhanced dielectric resonance of 1.5 times at 15.3 GHz due to the increased O-vacancy concentration in the CeO2 cores of larger grains as well as the O-vacancy-induced enhancement in interfacial polarization between the CeO2 cores and the Fe3O4 shells, respectively. Both nanocapsules exhibit relatively high permeability in the low-frequency S and C microwave bands as a result of the bi-magnetic core/shell combination of CeO2 and Fe3O4. The CeO2/Fe3O4 nanocapsules effectively enhance permittivity and permeability in the high-frequency Ku band with interfacial polarization and natural resonance at ∼15 GHz, thereby improving absorption with a large reflection loss of -28.9 dB at 15.3 GHz. Experimental and theoretical comparisons with CeO2 and Fe3O4 nanoparticles are also made.

  15. RESPONSE OF SOIL MICROBIAL BIOMASS TO CeO2 NANOPARTICLES

    Directory of Open Access Journals (Sweden)

    Livia Vittori Antisari

    2011-12-01

    Full Text Available Aim of this work was to assess the impact of the chronic exposure of CeO2 nanoparticles (NPs (50 to 105 nm nominal size on soil microbial biomass.To evaluate if the CeO2 NPs can affect the soil quality, they were mixed to an A1 and A2 horizon of Epileptic Cambisols at a concentrations of 100 ppm and incubated in lab for short and medium (7 and 60 days times, at a constant temperature (25°C and moisture (60% WHC.The preliminary results of the soil physicochemical analyses have showed an insolubility of the CeO2 NPs at short-term incubation in water, EDTA and aqua regia. The biological assays detect a storing of Ce-CeO2 in the microbial biomass at short time that decreases in the C amount. An increment of the basal respiration and a decrease in the amount of carbon soil microbial biomass determined a higher metabolic quotient (qCO2 than the control test, that identifies a stressful situation, most evident in the short term condition.Physical-chemical characterization of the CeO2 NPs and of the soil before and after the NPs addition, was carried out by means of Environmental Scanning Electron Microscope (ESEM and an Energy Dispersive Spectroscopy (EDS. The investigations showed Ce-NPs and Ce-compounds in both- incubation-condition samples. The control soil showed the presence of cerium associated with other elements, like P, Nd, La, Th e Si. From literature, it appears that these elements identify Monazite-Ce/Nd minerals, whose chemical formulas are respectively (Ce, La, Nd, Th PO4 and (Nd, Ce, La (P, Si O4. The presence of CeO2 NPs was clearly detected in soil and recognized by ESEM morphological observations coupled with EDS characterization. The NPs chemical composition appears unaltered, while the size can be modified by NPs aggregation and clustering.The results contribute to setting reference baseline values of cerium in soil and indicate an impact on the amount of carbon soil microbial biomass due to a higher metabolic quotient (qCO2 that

  16. Evaluation of Pd Nanoparticle-Decorated CeO2-MWCNT Nanocomposite as an Electrocatalyst for Formic Acid Fuel Cells

    Science.gov (United States)

    Saleem, Junaid; Safdar Hossain, SK.; Al-Ahmed, Amir; Rahman, Ateequr; McKay, Gordon; Hossain, Mohammed M.

    2018-01-01

    In this work, CeO2-modified Pd/CeO2-carbon nanotube (CNT) electrocatalyst for the electro-oxidation of formic acid has been investigated. The support CNT was first modified with different amounts (5-30 wt.%) of CeO2 using a precipitation-deposition method. The electrocatalysts were developed by dispersing Pd on the CeO2-CNT supports using the borohydride reduction method. The synthesized electrocatalysts were analyzed for composition, morphology and electronic structure using x-ray diffraction (XRD), scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM/EDX), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA) techniques. The formation of Pd nanoparticles on the CeO2-CNT support was confirmed using TEM. The activity of Pd/CeO2-CNT and of Pd-CNT samples upon oxidation of formic acid was evaluated by using carbon monoxide stripping voltammetry, cyclic voltammetry, and chronoamperometry. The addition of moderate amounts of cerium oxide (up to 10 wt.%) significantly improved the activity of Pd/CeO2-CNT compared to the unmodified Pd-CNT. Pd/10 wt.% CeO2-CNT showed a current density of 2 A mg-1, which is ten times higher than that of the unmodified Pd-CNT (0.2 A mg-1). Similarly, the power density obtained for Pd/10 wt.% CeO2-CNT in an air-breathing formic acid fuel cell was 6.8 mW/cm2 which is two times higher than Pd-CNT (3.2 mW/cm2), thus exhibiting the promotional effects of CeO2 to Pd/CeO2-CNT. A plausible justification for the improved catalytic performance and stability is provided in the light of the physical characterization results.

  17. Role of Microstructure and Surface Defects on the Dissolution Kinetics of CeO2, a UO2 Fuel Analogue.

    Science.gov (United States)

    Corkhill, Claire L; Bailey, Daniel J; Tocino, Florent Y; Stennett, Martin C; Miller, James A; Provis, John L; Travis, Karl P; Hyatt, Neil C

    2016-04-27

    The release of radionuclides from spent fuel in a geological disposal facility is controlled by the surface mediated dissolution of UO2 in groundwater. In this study we investigate the influence of reactive surface sites on the dissolution of a synthesized CeO2 analogue for UO2 fuel. Dissolution was performed on the following: CeO2 annealed at high temperature, which eliminated intrinsic surface defects (point defects and dislocations); CeO2-x annealed in inert and reducing atmospheres to induce oxygen vacancy defects and on crushed CeO2 particles of different size fractions. BET surface area measurements were used as an indicator of reactive surface site concentration. Cerium stoichiometry, determined using X-ray Photoelectron Spectroscopy (XPS) and supported by X-ray Diffraction (XRD) analysis, was used to determine oxygen vacancy concentration. Upon dissolution in nitric acid medium at 90 °C, a quantifiable relationship was established between the concentration of high energy surface sites and CeO2 dissolution rate; the greater the proportion of intrinsic defects and oxygen vacancies, the higher the dissolution rate. Dissolution of oxygen vacancy-containing CeO2-x gave rise to rates that were an order of magnitude greater than for CeO2 with fewer oxygen vacancies. While enhanced solubility of Ce(3+) influenced the dissolution, it was shown that replacement of vacancy sites by oxygen significantly affected the dissolution mechanism due to changes in the lattice volume and strain upon dissolution and concurrent grain boundary decohesion. These results highlight the significant influence of defect sites and grain boundaries on the dissolution kinetics of UO2 fuel analogues and reduce uncertainty in the long term performance of spent fuel in geological disposal.

  18. Solid state speciation of uranium and its local structure in Sr2CeO4 using photoluminescence spectroscopy

    Science.gov (United States)

    Sahu, M.; Gupta, Santosh K.; Jain, D.; Saxena, M. K.; Kadam, R. M.

    2018-04-01

    An effort was taken to carry our speciation study of uranium ion in technologically important cerate host Sr2CeO4 using time resolved photoluminescence spectroscopy. Such studies are not relevant only to nuclear industry but can give rich insight into fundamentals of 5f electron chemistry in solid state systems. In this work both undoped and varied amount of uranium doped Sr2CeO4 compound is synthesized using complex polymerization method and is characterized systematically using X-ray diffraction (XRD), Raman spectroscopy, photoluminescence spectroscopy and scanning electron microscopy (SEM). Both XRD and Raman spectroscopy confirmed the formation of pure Sr2CeO4 which has tendency to decompose peritectically to SrCeO3 and SrO at higher temperature. Uranium doping is confirmed by XRD. Uranium exhibits a rich chemistry owing to its variable oxidation state from +3 to +6. Each of them exhibits distinct luminescence properties either due to f-f transitions or ligand to metal charge transfer (LMCT). We have taken Sr2CeO4 as a model host lattice to understand the photophysical characteristics of uranium ion in it. Emission spectroscopy revealed the stabilization of uranium as U (VI) in the form of UO66- (octahedral uranate) in Sr2CeO4. Emission kinetics study reflects that uranate ions are not homogeneously distributed in Sr2CeO4 and it has two different environments due to its stabilization at both Sr2+ as well as Ce4+ site. The lifetime population analysis interestingly pinpointed that majority of uranate ion resided at Ce4+ site. The critical energy-transfer distance between the uranate ion was determined based on which the concentration quenching mechanism was attributed to electric multipolar interaction. These studies are very important in designing Sr2CeO4 based optoelectronic material as well exploring it for actinides studies.

  19. Investigating the effect of Mn-doped CeO2 nanoparticles by co-precipitation method

    Science.gov (United States)

    Prabaharan, D. Durai Manoharadoss; Sadaiyandi, K.; Mahendran, M.; Sagadevan, Suresh

    2018-02-01

    The paper exhibits a detailed study about the synthesis and characterization in analysis of structural, morphological, optical and electrical investigations of pure and Mn-doped Cerium oxide (CeO2) nanoparticles which were synthesized by co-precipitation technique. Phase formation of the prepared sample was analyzed with powder X-ray diffraction (PXRD) examines, scanning electron microscopy (SEM) examination. The PXRD comes about affirmed partial crystallinity having cubic phases and the crystallite sizes of the pure and Mn-doped Cerium oxide (CeO2) were estimated by utilizing Debye-Scherrer's formula and they were calculated to be 12 and 14 nm individually. SEM pictures revealed that the particles were profoundly accumulated and were of permeable nature. The optical properties of pure and Mn-doped CeO2 were ascertained by using UV-visible absorption spectrum. The estimated band gap values for the pure and the Mn-doped CeO2 nanoparticles were observed to be 2.7 and 2.6 eV, respectively, utilizing UV-Vis spectroscopy. At different frequencies and temperatures the dielectric properties of the Mn-doped Cerium oxide (CeO2) nanoparticles, for example, the dielectric consistent, the dielectric loss and the AC conductivity, were studied.

  20. Effect of CeO2-coating on the electrochemical performances of LiFePO4/C cathode material

    International Nuclear Information System (INIS)

    Yao Jingwen; Wu Feng; Qiu Xinping; Li Ning; Su Yuefeng

    2011-01-01

    Highlights: → The first study the effect of CeO 2 coating on LiFePO 4 /C at low temperature. → Coated cathode shows improved capacities at high rates and low temperature. → CeO 2 -coating decreases electrode polarization and increases charge-transfer reaction activity. - Abstract: The effect of CeO 2 coating on LiFePO 4 /C cathode material has been investigated. The crystalline structure and morphology of the synthesized powders have been characterized by XRD, SEM, TEM and their electrochemical performances both at room temperature and low temperature are evaluated by CV, EIS and galvanostatic charge/discharge tests. It is found that, nano-CeO 2 particles distribute on the surface of LiFePO 4 without destroying the crystal structure of the bulk material. The CeO 2 -coated LiFePO 4 /C cathode material shows improved lithium insertion/extraction capacity and electrode kinetics, especially at high rates and low temperature. At -20 deg. C, the CeO 2 -coated material delivers discharge capacity of 99.7 mAh/g at 0.1C rate and the capacity retention of 98.6% is obtained after 30 cycles at various charge/discharge rates. The results indicate that the surface treatment should be an effective way to improve the comprehensive properties of the cathode materials for lithium ion batteries.

  1. Nonvolatile Flash Memory Devices Using CeO2 Nanocrystal Trapping Layer for Two-Bit per Cell Applications

    Science.gov (United States)

    Yang, Shao-Ming; Chien, Chao-Hsin; Huang, Jiun-Jia; Lei, Tan-Fu

    2007-06-01

    In this study, we demonstrated the characteristics of nonvolatile silicon oxide nitride oxide silicon (SONOS)-type memories using cerium oxide (CeO2) nanocrystals as a charge storage agent. We observed that the shape of the formed CeO2 nanocrystals is nearly spherical and that their size is almost similar identical to their high density of 5× 1011 cm-2. Such CeO2 nanocrystals were formed by depositing a thin CeO2 film of ca. 2-3 nm thickness using an evaporater gun system and then rapid thermal annealing (RTA) in O2 ambient at 900 °C for 1 min. The fabricated memory devices show good electrical properties in terms of a sufficiently large memory window (>2 V), program/erase (P/E) speed (0.1/1 ms), retention time up to 104 s with only 5% charge loss, and endurance after 105 cycles with small memory window narrowing and two-bit operation. These properties suggest that the nonvolatile SONOS-type memories with the CeO2 nanocrystal trapping agent can be applied in future flash memories.

  2. Influence of Various Surfactants on Size, Morphology, and Optical Properties of CeO2 Nanostructures via Facile Hydrothermal Route

    Directory of Open Access Journals (Sweden)

    S. Gnanam

    2013-01-01

    Full Text Available Different surfactants such as sodium dodecyl sulfate (SDS, polyethylene glycol (PEG, and cetyltrimethyl ammonium bromide (CTAB, assisted cerium oxide (CeO2 nanoparticles were synthesized by using cerium chloride and potassium hydroxide as the starting materials via facile hydrothermal route. The powder X-ray diffraction (XRD shows that cubic fluorite-type structure of pure CeO2 and the average crystallite sizes were calculated to be ~12–16 nm. Raman spectra of various surfactants assisted CeO2 consist of a single triply degenerated F2g mode characteristic of the fluorite structure. The elongated spherical-like morphology of SDS assisted CeO2 samples was observed from the SEM and TEM studies. Optical absorption spectra showed a blue shift by the capped CeO2 due to the quantum confinement effect. Photoluminescence (PL emission studies shows that there is a change in the intensity of emission peaks by the capping agents, which indicates that the capping layers did result in size changes or increased surface defect.

  3. Early cephalometric characteristics in Class III malocclusion

    OpenAIRE

    Farias,Vanessa Costa; Tesch,Ricardo de Souza; Denardin,Odilon Victor Porto; Ursi,Weber

    2012-01-01

    OBJECTIVE: Early identification of craniofacial morphological characteristics allows orthopedic segmented interventions to attenuate dentoskeletal discrepancies, which may be partially disguised by natural dental compensation. To investigate the morphological characteristics of Brazilian children with Class III malocclusion, in stages I and II of cervical vertebrae maturation and compare them with the characteristics of Class I control patients. METHODS: Pre-orthodontic treatment records of 2...

  4. Factors Related to In-Class Spiritual Experience: Relationship between Pre-Class Scripture Reading, In-Class Note-Taking, and Perceived In-Class Spiritual Experiences

    Science.gov (United States)

    Hilton, John, III; Sweat, Anthony R.; Plummer, Kenneth

    2015-01-01

    The purpose of this study is to examine the relationship between student in-class note-taking and pre-class reading with perceived in-class spiritual and religious outcomes. This study surveyed 620 students enrolled in six different sections of an introductory religion course at a private religious university. Full-time religious faculty members…

  5. Oxygen vacancies versus fluorine at CeO2(111): a case of mistaken identity?

    Science.gov (United States)

    Kullgren, J; Wolf, M J; Castleton, C W M; Mitev, P; Briels, W J; Hermansson, K

    2014-04-18

    We propose a resolution to the puzzle presented by the surface defects observed with STM at the (111) surface facet of CeO 2 single crystals. In the seminal paper of Esch et al. [Science 309, 752 (2005)] they were identified with oxygen vacancies, but the observed behavior of these defects is inconsistent with the results of density functional theory (DFT) studies of oxygen vacancies in the literature. We resolve these inconsistencies via DFT calculations of the properties of both oxygen vacancies and fluorine impurities at CeO2(111), the latter having recently been shown to exist in high concentrations in single crystals from a widely used commercial source of such samples. We find that the simulated filled-state STM images of surface-layer oxygen vacancies and fluorine impurities are essentially identical, which would render problematic their experimental distinction by such images alone. However, we find that our theoretical results for the most stable location, mobility, and tendency to cluster, of fluorine impurities are consistent with experimental observations, in contrast to those for oxygen vacancies. Based on these results, we propose that the surface defects observed in STM experiments on CeO2 single crystals reported heretofore were not oxygen vacancies, but fluorine impurities. Since the similarity of the simulated STM images of the two defects is due primarily to the relative energies of the 2p states of oxygen and fluorine ions, this confusion might also occur for other oxides which have been either doped or contaminated with fluorine.

  6. Exposure of agricultural crops to nanoparticle CeO2in biochar-amended soil.

    Science.gov (United States)

    Servin, Alia D; De la Torre-Roche, Roberto; Castillo-Michel, Hiram; Pagano, Luca; Hawthorne, Joseph; Musante, Craig; Pignatello, Joseph; Uchimiya, Minori; White, Jason C

    2017-01-01

    Biochar is seeing increased usage as an amendment in agricultural soils but the significance of nanoscale interactions between this additive and engineered nanoparticles (ENP) remains unknown. Corn, lettuce, soybean and zucchini were grown for 28 d in two different soils (agricultural, residential) amended with 0-2000 mg engineered nanoparticle (ENP) CeO 2  kg -1 and biochar (350 °C or 600 °C) at application rates of 0-5% (w/w). At harvest, plants were analyzed for biomass, Ce content, chlorophyll and lipid peroxidation. Biomass from the four species grown in residential soil varied with species and biochar type. However, biomass in the agricultural soil amended with biochar 600 °C was largely unaffected. Biochar co-exposure had minimal impact on Ce accumulation, with reduced or increased Ce content occurring at the highest (5%) biochar level. Soil-specific and biochar-specific effects on Ce accumulation were observed in the four species. For example, zucchini grown in agricultural soil with 2000 mg CeO 2  kg -1 and 350 °C biochar (0.5-5%) accumulated greater Ce than the control. However, for the 600 °C biochar, the opposite effect was evident, with decreased Ce content as biochar increased. A principal component analysis showed that biochar type accounted for 56-99% of the variance in chlorophyll and lipid peroxidation across the plants. SEM and μ-XRF showed Ce association with specific biochar and soil components, while μ-XANES analysis confirmed that after 28 d in soil, the Ce remained largely as CeO 2 . The current study demonstrates that biochar synthesis conditions significantly impact interactions with ENP, with subsequent effects on particle fate and effects. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  7. Promoting employee voice and upward communication in healthcare: the CEO's influence.

    Science.gov (United States)

    Adelman, Kimberly

    2012-01-01

    As noted by the Institute of Medicine (2004), a lack of critical upward feedback in the hospital setting has adverse effects on direct patient care and health outcomes. Employees are oftentimes reluctant to share information, as those above them might interpret the information to be negative or threatening. Leaders then may make important decisions based on assumptions or inaccurate feedback. The situation is especially significant in the healthcare setting, where hierarchical structures (Nembhard and Edmondson 2006), divisions between administrators and clinicians, and lack of collaboration across teams reinforce employee silence and undermine organizational learning (Ramanujam and Rousseau 2006). Chief executive officers play a key role in developing a culture that fosters employee voice and upward communication (Ashford, Sutcliffe, and Christianson 2009). Hospitals winning performance excellence awards, such as those utilizing the Malcolm Baldrige National Quality Award Criteria for Performance Excellence, present a model of high performance with demonstrated results. The purpose of this study was to understand specific CEO behaviors and actions promoting employee voice and upward communication in performance excellence award-winning healthcare organizations. Results suggested the award-winning CEOs facilitated employee voice by being approachable, mainly achieved through their regular presence throughout the organization. By being consistently visible and available to employees these CEOs fostered relationships, built trust, and promoted open communication. Leaders in the study created a cultural focus on continuous improvement largely built around transparency of information, particularly looking for the bad news from their employees. Voice invitation and positive voice response from leaders reinforced that critical upward feedback is not only welcome, but expected.

  8. The CEO as organizational architect: an interview with Xerox's Paul Allaire. Interview by Robert Howard.

    Science.gov (United States)

    Allaire, P

    1992-01-01

    As chairman and CEO of the Xerox Corporation, Paul Allaire leads a company that is a microcosm of the changes transforming American business. With the introduction of the first plain-paper copier in 1959, Xerox invented a new industry and launched itself on a decade of spectacular growth. But easy growth led Xerox to neglect the fundamentals of its core business, leaving the company vulnerable to low-cost Japanese competition. Starting in the mid-1980s, Xerox embarked on a long-term effort to regain its dominant position in world copier markets and to create a new platform for future growth. Thanks to the company's Leadership through Quality program, Xerox became the first major U.S. company to win back market share from the Japanese. Allaire describes his efforts to take Xerox's corporate transformation to a new level. Since becoming CEO in 1990, he has repositioned Xerox as "the document company" at the intersection of the worlds of paper-based and electronic information. And he has guided the company through a fundamental redesign of what he calls the "organizational architecture" of Xerox's document processing business. Few CEOs have approached the process of organizational redesign as systematically and methodically as Allaire has. He has created a new corporate structure that balances independent business divisions with integrated R&D and customer operations organizations. He has redefined managerial roles and responsibilities, changed the way managers are selected and compensated, and renewed the company's senior management ranks. And he has articulated the new values and behaviors Xerox managers will need to thrive in a more competitive and fast-changing business environment.

  9. A time for growth: an interview with Amgen CEO Kevin Sharer. Interview by Paul Hemp.

    Science.gov (United States)

    Sharer, Kevin

    2004-01-01

    Fast growth is a nice problem to have--but a hard one to manage well. In this interview, Kevin Sharer, the CEO of biotech giant Amgen, talks about the special challenges leaders face when their companies are on a roll. Sharer, who was also head of marketing at pre-WorldCom MCI and a division head and a staff assistant to Jack Welch at GE, offers insights drawn from his own experience--and from his own self-proclaimed blunders: "I learned the hard way that you need to become credible and enlist support inside the company before you start trying to be a change agent. If you think you're going to make change happen simply by force of personality or position or intellect, you'd better think again." And change there was: Under Sharer's leadership, Amgen overhauled its management team, altered its culture, and launched a couple of blockbuster products. How do chief executives survive in that kind of dizzying environment? "A CEO must always be switching between different altitudes--tasks of different levels of abstraction and specificity," Sharer says. "You might need to spend time working on a redesign of your organizational structure and then quickly switch to drafting a memo to all employees aimed at reinforcing one of the company's values." Having a supportive and capable top team is also key: "A top management team is the most revealing window into a CEO's style, values, and aspirations.... If you don't have the right top team, you won't have the right tiers below them. [The] A players won't work for B players. Maybe with a company like GE, the reputation of the company is so strong that it can attract top people to work for weaker managers. In a new company like Amgen, that won't happen."

  10. CEO Appointments and the Loss of Firm-Specific Knowledge - Putting Integrity Back into Hiring Decisions

    DEFF Research Database (Denmark)

    Rost, Katja; Salomo, Søren; Osterloh, Margit

    2008-01-01

    that over the past decades the dishonesty of the predecessor has become relatively more important for the appointment decisions of firms. We conclude that outside hires are a suboptimal trend because external candidates even step up the regression of integrity in firms: As nobody has an incentive to invest......A rarely studied trend in corporate governance is the increasing tendency to fill CEO openings through external hires rather than through internal promotions: Kevin J. Murphy and Ján Zábojník (2004) show that the proportion of outside hires has doubled and their pay premium almost quadrupled over...

  11. CEO Appointments and the Loss of Firm-specific Knowledge - Putting Integrity Back into Hiring Decisions

    DEFF Research Database (Denmark)

    Rost, Katja; Salomo, Søren

    2008-01-01

    that over the past decades the dishonesty of the predecessor has become relatively more important for the appointment decisions of firms. We conclude that outside hires are a suboptimal trend because external candidates even step up the regression of integrity in firms: As nobody has an incentive to invest......A rarely studied trend in corporate governance is the increasing tendency to fill CEO openings through external hires rather than through internal promotions: Kevin J. Murphy and Ján Zábojník (2004) show that the proportion of outside hires has doubled and their pay premium almost quadrupled over...

  12. OILY WASTEWATER TREATMENT FOR CATALYTIC OXIDATION WITH K-MNO2/CeO2

    OpenAIRE

    JERÔNIMO, Carlos Enrique de Medeiros; FERNANDES, Hermano Gomes; SOUSA, João Fernandes

    2012-01-01

    The search for alternatives for the treatment of industrial effluents, especially high toxicity is one of the main difficulties of the industrial treatment systems. This work aims to use potassium as a promoter of electrons for the oxidation to the catalyst by impregnating it MnO2/CeO2 to degrade the effluent coming from the processing of cashew nuts in the presence of oxygen. The experiments were performed in a slurry bed reactor. In the experiments were kept constant initial concentratio...

  13. Shape memory lifetime of CeO2-stabilized tetragonal zirconia polycrystals

    International Nuclear Information System (INIS)

    Zhe Xiaoli; Li Bo; Meng Man

    1993-01-01

    Lifetime of shape memory effect (SME) of CeO 2 -stabilized tetragonal zirconia polycrystals was studied by means of both tests of constraint stress and constraint strain mode during reverse martensite transformation. Up to 8th cycling of SME, the shape of sample entirely recovered except microcracks in the constraint stress mode and the accumulated strain reached 4.6% in the constraint strain mode. It was found that the yield stress decreased, however, the reverse transformation temperature of stress-induced martensite increased with times of the cycling. The reason of these phenomena are discussed in terms of microcracking and strain energy relaxation

  14. The CEOS Global Observation Strategy for Disaster Risk Management: An Enterprise Architect's View

    Science.gov (United States)

    Moe, K.; Evans, J. D.; Frye, S.

    2013-12-01

    The Committee on Earth Observation Satellites (CEOS) Working Group on Information Systems and Services (WGISS), on behalf of the Global Earth Observation System of Systems (GEOSS), is defining an enterprise architecture (known as GA.4.D) for the use of satellite observations in international disaster management. This architecture defines the scope and structure of the disaster management enterprise (based on disaster types and phases); its processes (expressed via use cases / system functions); and its core values (in particular, free and open data sharing via standard interfaces). The architecture also details how a disaster management enterprise describes, obtains, and handles earth observations and data products for decision-support; and how it draws on distributed computational services for streamlined operational capability. We have begun to apply this architecture to a new CEOS initiative, the Global Observation Strategy for Disaster Risk Management (DRM). CEOS is defining this Strategy based on the outcomes of three pilot projects focused on seismic hazards, volcanoes, and floods. These pilots offer a unique opportunity to characterize and assess the impacts (benefits / costs) of the GA.4.D architecture in practice. In particular, the DRM Floods Pilot is applying satellite-based optical and radar data to flood mitigation, warning, and response, including monitoring and modeling at regional to global scales. It is focused on serving user needs and building local institutional / technical capacity in the Caribbean, Southern Africa, and Southeast Asia. In the context of these CEOS DRM Pilots, we are characterizing where and how the GA.4D architecture helps participants to: - Understand the scope and nature of hazard events quickly and accurately - Assure timely delivery of observations into analysis, modeling, and decision-making - Streamline user access to products - Lower barriers to entry for users or suppliers - Streamline or focus field operations in

  15. Effect of CeO2 on TiC Morphology in Ni-Based Composite Coating

    Science.gov (United States)

    Cai, Yangchuan; Luo, Zhen; Chen, Yao

    2018-03-01

    The TiC/Ni composite coating with different content of CeO2 was fabricated on the Cr12MoV steel by laser cladding. The microstructure of cladding layers with the different content of CeO2 from the bottom to the surface is columnar crystal, cellular crystal, and equiaxed crystal. When the content of CeO2 is 0 %, the cladding layer has a coarse and nonuniform microstructure and TiC particles gathering in the cladding layer, and then the wear resistance was reduced. Appropriate rare-earth elements refined and homogenised the microstructure and enhanced the content of carbides, precipitated TiC particles and original TiC particles were spheroidised and refined, the wear resistance of the cladding layer was improved significantly. Excessive rare-earth elements polluted the grain boundaries and made the excessive burning loss of TiC particles that reduced the wear resistance of the cladding layer.

  16. Effect of processing conditions and methods on residual stress in CeO2 buffer layers and YBCO superconducting films

    International Nuclear Information System (INIS)

    Xiong Jie; Qin Wenfeng; Cui Xumei; Tao Bowan; Tang Jinlong; Li Yanrong

    2006-01-01

    CeO 2 layers have been fabricated by pulsed laser deposition (PLD) technique on (1 1 0 2) sapphire substrate. Microstructure of CeO 2 layers is characterized by X-ray diffraction as functions of substrate temperature. The effects of the substrate temperature on the residual stress have been studied. The results show that residual stress in CeO 2 film decreased with increasing substrate temperature, not the same development tendency as that of thermal stress. This means that the thermal stress is only a fraction of the residual stress. Moreover, YBCO superconducting films were prepared by direct current (DC) sputtering and pulsed laser deposition (PLD) technique. The residual stress and thermal stress of both YBCO films were measured. PLD processing apparently generated higher intrinsic compressive stresses in comparison to DC sputtering

  17. Fabrication of multianalyte CeO2 nanograin electrolyte–insulator–semiconductor biosensors by using CF4 plasma treatment

    Directory of Open Access Journals (Sweden)

    Chyuan Haur Kao

    2015-09-01

    Full Text Available Multianalyte CeO2 biosensors have been demonstrated to detect pH, glucose, and urine concentrations. To enhance the multianalyte sensing capability of these biosensors, CF4 plasma treatment was applied to create nanograin structures on the CeO2 membrane surface and thereby increase the contact surface area. Multiple material analyses indicated that crystallization or grainization caused by the incorporation of flourine atoms during plasma treatment might be related to the formation of the nanograins. Because of the changes in surface morphology and crystalline structures, the multianalyte sensing performance was considerably enhanced. Multianalyte CeO2 nanograin electrolyte–insulator–semiconductor biosensors exhibit potential for use in future biomedical sensing device applications.

  18. In situ DRIFTS investigation of NH3-SCR reaction over CeO2/zirconium phosphate catalyst

    Science.gov (United States)

    Zhang, Qiulin; Fan, Jie; Ning, Ping; Song, Zhongxian; Liu, Xin; Wang, Lanying; Wang, Jing; Wang, Huimin; Long, Kaixian

    2018-03-01

    A series of ceria modified zirconium phosphate catalysts were synthesized for selective catalytic reduction of NO with ammonia (NH3-SCR). Over 98% NOx conversion and 98% N2 selectivity were obtained by the CeO2/ZrP catalyst with 20 wt.% CeO2 loading at 250-425 °C. The interaction between CeO2 and zirconium phosphate enhanced the redox abilities and surface acidities of the catalysts, resulting in the improvement of NH3-SCR activity. The in situ DRIFTS results indicated that the NH3-SCR reaction over the catalysts followed both Eley-Rideal and Langmuir-Hinshelwood mechanisms. The amide (sbnd NH2) groups and the NH4+ bonded to Brønsted acid sites were the important intermediates of Eley-Rideal mechanism.

  19. Direct synthesis of dimethyl carbonate from methanol and carbon dioxide over CeO2(X)-ZnO(1-X) nano-catalysts.

    Science.gov (United States)

    Kang, Ki Hyuk; Joe, Wangrae; Lee, Chang Hoon; Kim, Mieock; Kim, Dong Baek; Jang, Boknam; Song, In Kyu

    2013-12-01

    CeO2(X)-ZnO(1-X) (X = 0, 0.1, 0.3, 0.5, 0.7, 0.9, and 1.0) nano-catalysts were prepared by a co-precipitation method with a variation of CeO2 content (X, mol%), and they were applied to the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. Successful formation of CeO2(X)-ZnO(1-X) nano-catalysts was well confirmed by XRD analysis. The amount of DMC produced over CeO2(X)-ZnO(1-X) catalysts exhibited a volcano-shaped curve with respect to CeO2 content. Acidity and basicity of CeO2(X)-ZnO(1-X) nano-catalysts were measured by NH3-TPD and CO2-TPD experiments, respectively, to elucidate the effect of acidity and basicity on the catalytic performance in the reaction. It was revealed that the catalytic performance of CeO2(X)-ZnO(1-X) nano-catalysts was closely related to the acidity and basicity of the catalysts. Amount of dimethyl carbonate increased with increasing both acidity and basicity of the catalysts. Among the catalysts tested, CeO2(0.7)-ZnO(0.3) with the largest acidity and basicity showed the best catalytic performance in the direct synthesis of dimethyl carbonate from methanol and carbon dioxide.

  20. Synergic effect of the TiO2-CeO2 nanoconjugate system on the band-gap for visible light photocatalysis

    International Nuclear Information System (INIS)

    Contreras-García, M.E.; García-Benjume, M. Lorena; Macías-Andrés, Víctor I.; Barajas-Ledesma, E.; Medina-Flores, A.; Espitia-Cabrera, M.I.

    2014-01-01

    Graphical abstract: - Highlights: • Nanostructured TiO 2 -CeO 2 films are successfully synthesized by combining of sputtering and electrophoresis methods. • Synergic effect of CeO 2 on TiO 2 band gap was demonstrated, CeO 2 diminishes it from 3.125 to 2.74. • Morphologic characterization of the nanoconjugate TiO 2 -CeO 2 films by different microscopy techniques. - Abstract: The TiO 2 -CeO 2 photocatalytic system in films is proposed here, in order to obtain photocatalytic systems that can be excited by solar light. The films were obtained through the electrophoretic deposition (EPD) of TiO 2 -CeO 2 gel on sputtered Ti Corning glass substrates. The synergic effect of CeO 2 in TiO 2 films was analyzed as a function of the optical band gap reduction at different concentrations (1, 5, 10, and 15 mol%). The effect of two thermal treatments was also evaluated. The lowest band gap value was obtained for the sample with 5 mol% ceria that was thermally treated at 700 °C. The nanostructured films were characterized by Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high angle annular dark field (HAADF), high resolution transmission electron microscopy (HRTEM), and atomic force microscopy (AFM). The nanocomposites were formed by TiO 2 and CeO 2 nanoparticles in the anatase and fluorite type phases, respectively

  1. Parameters dependent studies of structural, optical and electrical properties of CeO2 nanoparticles prepared via facile one-pot hydrothermal technique

    Science.gov (United States)

    Mohanty, Biswajyoti; Nayak, J.

    2017-11-01

    Cerium oxide (CeO2) nanoparticles have exceptional optical and electronic properties due to the presence of unfilled 4f orbitals in CeO2. CeO2 nanocrystals have been used in semiconductor devices due to their high thermal and chemical stability. In this work, CeO2 nanoparticles were synthesized by a facile one-pot hydrothermal technique under various experimental conditions. The effects of various process parameters on optical, structural and electrical properties of the CeO2 nanoparticles were systematically studied. The morphology, composition and the structure of the CeO2 powders were studied by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDXA) and X-ray diffraction (XRD), respectively. The XRD pattern advocated that the synthesized cerium oxide nanoparticles exhibited a cubic fluorite structure. The average crystallite size estimated from the XRD peak width was 6–11 nm for the majority of the samples. The zeta sizer nano series analyzer provided a precise image of particle size distribution with a maximum at around 147.7 nm. The optical band gaps estimated from the diffused reflectance results were from 3.08 eV to 3.18 eV. A systematic variation in the photoluminescence intensity with a change in the crystallite sizes of CeO2 nanoparticles was observed. The variation of electrical property of CeO2 nanoparticles with a change in process parameters was analytically discussed.

  2. Relational Signalling and the Rise of CEO Compensation "...It is Not Just About Money, It is About What the Money Says..."

    NARCIS (Netherlands)

    van Veen, Kees; Wittek, Rafael

    The continuous rise in CEO compensation over the past few decades has been attributed either to efficient labor market processes (efficient market theories) or to corporate governance failures leading to insufficient control of boards over CEOs (managerial power theories). We argue that both

  3. Interfacial interactions of semiconductor with graphene and reduced graphene oxide: CeO2 as a case study.

    Science.gov (United States)

    Xu, Liang; Huang, Wei-Qing; Wang, Ling-Ling; Huang, Gui-Fang

    2014-11-26

    The pursuit of superb building blocks of light harvesting systems has stimulated increasing efforts to develop graphene (GR)-based semiconductor composites for solar cells and photocatalysts. One critical issue for GR-based composites is understanding the interaction between their components, a problem that remains unresolved after intense experimental investigation. Here, we use cerium dioxide (CeO2) as a model semiconductor to systematically explore the interaction of semiconductor with GR and reduced graphene oxide (RGO) with large-scale ab initio calculations. The amount of charge transferred at the interfaces increases with the concentration of O atoms, demonstrating that the interaction between CeO2 and RGO is much stronger than that between CeO2 and GR due to the decrease of the average equilibrium distance between the interfaces. The stronger interaction between semiconductor and RGO is expected to be general, as evidenced by the results of two paradigms of TiO2 and Ag3PO4 coupled with RGO. The interfacial interaction can tune the band structure: the CeO2(111)/GR interface is a type-I heterojunction, while a type-II staggered band alignment exists between the CeO2(111) surface and RGO. The smaller band gap, type-II heterojunction, and negatively charged O atoms on the RGO as active sites are responsible for the enhanced photoactivity of CeO2/RGO composite. These findings can rationalize the available experimental reports and enrich our understanding of the interaction of GR-based composites for developing high-performance photocatalysts and solar cells.

  4. Función de los opiáceos en el comportamiento defensivo del cangrejo Chasmagnathus Granulatus

    OpenAIRE

    Romano, Arturo Gabriel

    1991-01-01

    La morfina produjo una inhibición dosis dependiente de la respuesta defensiva de despliegue lateral del merus, provocada por un estímulo eléctrico de la superficie dorsal del cefalotórax. El antagonista opiáceo naloxono revirtió dicha inhibición, sugiriendo que están involucrados receptores opiáceos. La potencia de la morfina resultó similar a la observada en vertebrados, pero el tiempo de máxima acción y de vida media resultaron mucho menores. La morfina inhibió también la respuesta de escap...

  5. Investigation of CeO2 Buffer Layer Effects on the Voltage Response of YBCO Transition-Edge Bolometers

    DEFF Research Database (Denmark)

    Mohajeri, Roya; Nazifi, Rana; Wulff, Anders Christian

    2016-01-01

    The effect on the thermal parameters of superconducting transition-edge bolometers produced on a single crystalline SrTiO3 (STO) substrate with and without a CeO2 buffer layer was investigated. Metal-organic deposition was used to deposit the 20-nm CeO2 buffer layer, whereas RF magnetron sputtering...... responses, and the results were compared with that of simulations conducted by applying a one-dimensional thermophysical model. It was observed that adding the buffer layer to the structure of the bolometer results in an increased response at higher modulation frequencies. Results from simulations made...

  6. Board composition and performance in Spanish non-listed family firms: The influence of type of directors and CEO duality

    Directory of Open Access Journals (Sweden)

    Mª Katiuska Cabrera-Suárez

    2015-10-01

    Full Text Available This study analyzes the effect that certain characteristics of board of directors in Spanish non-listed family firms have on performance. The results of a hierarchical regression analysis on a database of 544 firms show a negative effect of a higher proportion of executive directors and a positive effect of CEO duality. No effects were found in relation to the diversity of family directors (executive or non-executive. In relation to the effect of outside boards, the influence on performance is negative except when this variable was considered in interaction with CEO duality. In this case, the effect on performance was positive.

  7. Study of effect of co-doping on CIE coordinates of strontium cerium oxide phosphor (Sr2CeO4)

    International Nuclear Information System (INIS)

    Zambare, Pradip Z.; Ahirrao, P.B.; Chaudhari, D.B.; Zambare, A.P.; Mahajan, O.H.

    2016-01-01

    The phosphors Sr 2 CeO 4 doped europium and gadolinium were synthesized by modified solid state diffusion method. From emission spectra, the CIE coordinates (x, y) of x% Eu 3+ and 0.5 %Gd 3+ doped Sr 2 CeO 4 phosphors was calculated. In present paper, we investigate luminescence properties and colorimetric study of Sr 2 CeO 4 doped 0.5% Gd 3+ , x% Eu 3+ . The phosphors Sr 2 CeO 4 doped europium and gadolinium were successfully synthesized by modified solid state diffusion method. X-ray diffraction (XRD) profile confirms the orthorhombic nature of Eu 3+ and 0.5% Gd 3+ doped Sr 2 CeO 4 phosphors. In addition, scanning electron Microscopy (SEM), Fourier-Transformation IR spectroscopy (FTIR), was also used to study the synthesized phosphors

  8. Structure of Nano-sized CeO2 Materials: Combined Scattering and Spectroscopic Investigations.

    Science.gov (United States)

    Marchbank, Huw R; Clark, Adam H; Hyde, Timothy I; Playford, Helen Y; Tucker, Matthew G; Thompsett, David; Fisher, Janet M; Chapman, Karena W; Beyer, Kevin A; Monte, Manuel; Longo, Alessandro; Sankar, Gopinathan

    2016-11-04

    The structure of several nano-sized ceria, CeO 2 , systems was investigated using neutron and X-ray diffraction and X-ray absorption spectroscopy. Whilst both diffraction and total pair distribution functions (PDFs) revealed that in all of the samples the occupancy of both Ce 4+ and O 2- are very close to the ideal stoichiometry, the analysis using Reverse Monte Carlo technique revealed significant disorder around oxygen atoms in the nano-sized ceria samples in comparison to the highly crystalline NIST standard. In addition, the analysis revealed that the main differences observed in the pair correlations from various X-ray and neutron diffraction techniques were attributable to the particle size of the CeO 2 prepared by the reported three methods. Furthermore, detailed analysis of the Ce L 3 - and K-edge EXAFS data support this finding; in particular the decrease in higher shell coordination numbers with respect to the NIST standard, is attributed to differences in particle size. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. The Efficiency of the European Non-Life Insurance: CEO Power, Macroeconomic, and Market Characteristics Impact

    Directory of Open Access Journals (Sweden)

    Walid Bahloul

    2016-03-01

    Full Text Available A numbers of studies focusing on the determinant of the insurance market efficiency have increased in the last decade. In fact, many factors, like the CEO’s power, can influence the efficiency in the insurance firm. The purpose of this research is to analyze the relationship between efficiency, measured by the cost function using the stochastic frontier approach (SFA methodologies, and the market structure, as well as the macroeconomic variables. In addition, it focuses on identifying the impact of the integration of the CEO power variable in the cost function on this relation. The result shows that after the consideration of the CEO power score in the cost efficiency, the relation between insurance efficiency and the determinant of market development, as well as the domestic economy, has changed and become more significant. The result also shows that the firms become more efficient and more profitable with a higher concentration ratio and this is in accordance with the structure-conduct-performance (SCP theory.

  10. Flower-Like Mn-Doped CeO2 Microstructures: Synthesis, Characterizations, and Catalytic Properties

    Directory of Open Access Journals (Sweden)

    Ling Liu

    2015-01-01

    Full Text Available Mn-doped CeO2 flower-like microstructures have been synthesized by a facile method, involving the precipitation of metallic alkoxide precursor in a polyol process from the reaction of CeCl3·7H2O with ethylene glycol in the presence of urea followed by calcination. By introducing manganese ions, the composition can be freely manipulated. To investigate whether there was a hybrid synergic effect in CH4 combustion reaction, further detailed characteristics of Mn-doped CeO2 with various manganese contents were revealed by XRD, Raman, FT-IR, SEM, EDS, XPS, OSC, H2-TPR, and N2 adsorption-desorption measurements. The doping manganese is demonstrated to increase the storage of oxygen vacancy for CH4 and enhance the redox capability, which can efficiently convert CH4 to CO2 and H2O under oxygen-rich condition. The excellent catalytic performance of MCO-3 sample, which was obtained with the starting Mn/Ce ratios of 0.2 in the initial reactant compositions, is associated with the larger surface area and richer surface active oxygen species.

  11. Electrical and microstructural properties of Yb-doped CeO2

    Directory of Open Access Journals (Sweden)

    B. Matović

    2014-06-01

    Full Text Available Nanopowdered Ce1−xYbxO2−δ solid solutions (0 ≤ x ≤ 0.2 were synthesized by a self-propagating room temperature synthesis. XRD and SEM were used to study the properties of these materials as well as the Yb solubility in CeO2 lattice. Results showed that all the obtained powders were solid solutions with a fluorite-type crystal structure and with nanometric particle size. The average size of Ce1−xYbxO2−δ particles was approximately 3 nm. Electrochemical impedance spectroscopy for the sintered pellets depicted that it was possible to separate Rbulk and Rgb in the temperature interval of 550–800 °C. The activation energy for the bulk conduction was 1.03 eV and for grain boundary conduction was 1.14 eV. Grain boundary resistivity dominates over the other resistivities. These measurements confirmed that Yb3+-doped CeO2 material had a potential as electrolyte for intermediate-temperature solid oxide fuel cell applications.

  12. Ab initio thermodynamic evaluation of Pd atom interaction with CeO(2) surfaces.

    Science.gov (United States)

    Mayernick, Adam D; Janik, Michael J

    2009-08-28

    Palladium supported on ceria is an effective catalytic material for three-way automotive catalysis, catalytic combustion, and solid-oxide fuel cell (SOFC) anodes. The morphology, oxidation state, and particle size of Pd on ceria affect catalytic activity and are a function of experimental conditions. This work utilizes ab initio thermodynamics using density functional theory (DFT) (DFT+U) methods to evaluate the stability of Pd atoms, PdO(x) species, and small Pd particles in varying configurations on CeO(2) (111), (110), and (100) single crystal surfaces. Over specific oxygen partial pressure and temperature ranges, palladium incorporation to form a mixed surface oxide is thermodynamically favorable versus other single Pd atom states on each ceria surface. For example, Pd atoms may incorporate into Ce fluorite lattice positions in a Pd(4+) oxidation state on the CeO(2) (111) surface. The ceria support shifts the transition between formal Pd oxidation states (Pd(0), Pd(2+), Pd(4+)) relative to bulk palladium and stabilizes certain oxidized palladium species on each surface. We show that temperature, oxygen pressure, and cell potential in a SOFC can influence the stable states of palladium supported on ceria surfaces, providing insight into structural stability during catalytic operation.

  13. Pênfigo foliáceo em um eqüino Pemphigus foliaceus in a horse

    Directory of Open Access Journals (Sweden)

    Gabriel Augusto Monteiro

    2007-04-01

    Full Text Available Pênfigo foliáceo é uma rara afecção cutânea auto-imune que acomete várias espécies. Relata-se o caso de uma égua de quatro anos de idade, sem raça definida, apresentando áreas de alopecia, exsudação e crostas localizadas na face, região peitoral e membros pélvicos, além de prurido. Os exames laboratoriais para pesquisa de ácaros, bactérias e estruturas fúngicas foram negativos. O exame histopatológico revelou uma dermatite pustular intra-epidérmica com acantólise subcorneal, assim como dermatite perivascular superficial, com infiltração de eosinófilos, sendo o quadro compatível com pênfigo foliáceo.Pemphigus foliaceus is an uncommon autoimmune skin disorder affecting various species. A case of a 4-year-old mare of undefined breed, displaying alopecic areas, exsudation and crusty lesions on the face, breast region, and hindlimbs as well as pruritus, is reported. Laboratory exams for mite, bacteria and fungal structures were negative. Histopathological exam revealed an intra-epidermal pustule dermatitis with acantholysis, as well as superficial perisvascular dermatitis with infiltration of eosinophyles, conditions compatible with pemphigus foliaceus.

  14. Using an In-Class Simulation in the First Accounting Class: Moving from Surface to Deep Learning

    Science.gov (United States)

    Phillips, Mary E.; Graeff, Timothy R.

    2014-01-01

    As students often find the first accounting class to be abstract and difficult to understand, the authors designed an in-class simulation as an intervention to move students toward deep learning and away from surface learning. The simulation consists of buying and selling merchandise and accounting for transactions. The simulation is an effective…

  15. 76 FR 65696 - Request for Applicants for the Appointment to the United States-Brazil CEO Forum

    Science.gov (United States)

    2011-10-24

    ... Forum AGENCY: International Trade Administration, Department of Commerce. ACTION: Notice. SUMMARY: In March 2007, the Governments of the United States and Brazil established the U.S.-Brazil CEO Forum. This... representatives to the current U.S. Section of the Forum. The current U.S. Section term will expire on August 12...

  16. 77 FR 7132 - Request for Applicants for the Appointment to the United States-India CEO Forum

    Science.gov (United States)

    2012-02-10

    ... Forum AGENCY: Market Access and Compliance, International Trade Administration, Department of Commerce....-India CEO Forum. This notice announces membership opportunities for appointment or reappointment as representatives to the U.S. Section of the Forum's private sector Committee. DATES: Applications should be...

  17. Cetáceos de las aguas costeras del Pacífico norte y sur de Costa Rica

    Directory of Open Access Journals (Sweden)

    Damián Martínez-Fernández

    2011-03-01

    Full Text Available De las 29 especies de cetáceos presentes en Costa Rica, se han realizado investigaciones exhaustivas solamente para tres especies. Lo anterior evidencia la poca información general existente sobre cetáceos, a pesar de que Costa Rica posee un notable crecimiento de actividades de avistamiento. Debido al uso que se está generando en las zonas costeras, cada vez se hace más necesario determinar la ocurrencia de cetáceos en zonas de alta actividad turística, con el fin de proponer medidas de conservación. En el presente estudio, se determinaron variables ambientales que estaban relacionadas con la presencia de especies registradas, a partir de 166 avistamientos entre el 2005 y 2006. Las especies con mayor proporción de avistamientos fueron Stenella attenuata (68%, seguida por Megaptera novaeangliae (13% y Tursiops truncatus (10%. La presencia del delfín manchado se relaciona con cambios de salinidad y trasparencia del agua, mientras que la de la ballena jorobada estuvo relacionada con el oleaje y la temperatura superficial del agua. Se confirma la presencia de 7 especies de cetáceos en dos zonas costeras del Pacífico de Costa Rica, de las cuales tres están presentes a lo largo del año. Se encontraron variables ambientales relacionadas con la presencia de al menos dos especies.

  18. Optimization of CeO2-ZrO2 mixed oxide catalysts for ethyl acetate combustion

    Czech Academy of Sciences Publication Activity Database

    Dimitrov, M.; Ivanova, R.; Štengl, Václav; Henych, Jiří; Kovacheva, D.; Tsoncheva, T.

    2015-01-01

    Roč. 47, č. 1 (2015), s. 323-329 ISSN 0324-1130 Institutional support: RVO:61388980 Keywords : nanosized CeO2-ZrO2 * mixed oxide phase * ethyl acetate combustion Subject RIV: CA - Inorganic Chemistry Impact factor: 0.229, year: 2015

  19. 78 FR 65290 - Request for Applicants for the Appointment to the United States-India CEO Forum

    Science.gov (United States)

    2013-10-31

    ... Appointment to the United States- India CEO Forum AGENCY: Global Markets, International Trade Administration... President (or have a comparable level of responsibility) of a U.S.-owned or controlled company that is... doing business in both India and the United States. Each candidate also must be a U.S. citizen or...

  20. Solid state sintering of lime in presence of La2O3 and CeO2

    Indian Academy of Sciences (India)

    Unknown

    Abstract. The sintering of lime by double calcination process from natural limestone has been conducted with La2O3 and CeO2 additive up to 4 wt.% in the temperature range 1500–1650°C. The results show that the additives enhanced the densification and hydration resistance of sintered lime. Densification is achieved up ...

  1. Nano composite of CeO2 and High-Coercivity Magnetic Carrier with Large Specific Surface Area

    International Nuclear Information System (INIS)

    Mantlikova, A. R.; Pacakova, B.; Kubickova, S.; Vejpravova, J.; Plocek, J.; Vik, O.; Niznansky, D.; Slouf, M.

    2016-01-01

    We succeeded in the preparation of CoFe 2 O 4 /CeO 2 nano composites with very high specific surface area (up to 264 g/m 2 ). First, highly crystalline nanoparticles (NP s ) of CoFe 2 O 4 (4.7 nm) were prepared by hydrothermal method in water-alcohol-oleic acid system. The oleate surface coating was subsequently modified by ligand exchange to citrate. Then the NP s were embedded in CeO 2 using heterogeneous precipitation from diluted Ce 3 + sulphate solution. Dried samples were characterized by Powder X-Ray Diffraction, Energy Dispersive X-Ray Analysis, Scanning and Transmission Electron Microscopy, Moessbauer Spectroscopy, and Brunauer-Emmett-Teller method. Moreover, detailed investigation of magnetic properties of the bare NP s and final composite was carried out. We observed homogeneous embedding of the magnetic NP s into the CeO 2 without significant change of their size and magnetic properties. We have thus demonstrated that the proposed synthesis method is suitable for preparation of extremely fine CeO 2 nano powders and their nano composites with NP s . The morphology and magnetic nature of the obtained nano composites make them a promising candidate for magneto responsive catalysis.

  2. Solid state sintering of lime in presence of La2O3 and CeO2

    Indian Academy of Sciences (India)

    The sintering of lime by double calcination process from natural limestone has been conducted with La2O3 and CeO2 additive up to 4 wt.% in the temperature range 1500–1650°C. The results show that the additives enhanced the densification and hydration resistance of sintered lime. Densification is achieved up to 98.5% ...

  3. Consensus on the leadership of hospital CEOs and its impact on the participation of physicians in improvement projects

    NARCIS (Netherlands)

    Dückers, Michel L.A.; Stegeman, Inge; Spreeuwenberg, Peter; Wagner, Cordula; Sanders, Karin; Groenewegen, Peter P.

    2009-01-01

    Objectives: The success of a Dutch program to disseminate quality improvement projects depends on the participation of physicians working in program hospitals. The leadership of hospital executives (CEOs) is considered an important explanation. This study aims to determine whether the relation,

  4. Nanocomposite of CeO2 and High-Coercivity Magnetic Carrier with Large Specific Surface Area

    Directory of Open Access Journals (Sweden)

    Alice Reznickova Mantlikova

    2016-01-01

    Full Text Available We succeeded in the preparation of CoFe2O4/CeO2 nanocomposites with very high specific surface area (up to 264 g/m2. First, highly crystalline nanoparticles (NPs of CoFe2O4 (4.7 nm were prepared by hydrothermal method in water-alcohol-oleic acid system. The oleate surface coating was subsequently modified by ligand exchange to citrate. Then the NPs were embedded in CeO2 using heterogeneous precipitation from diluted Ce3+ sulphate solution. Dried samples were characterized by Powder X-Ray Diffraction, Energy Dispersive X-Ray Analysis, Scanning and Transmission Electron Microscopy, Mössbauer Spectroscopy, and Brunauer-Emmett-Teller method. Moreover, detailed investigation of magnetic properties of the bare NPs and final composite was carried out. We observed homogeneous embedding of the magnetic NPs into the CeO2 without significant change of their size and magnetic properties. We have thus demonstrated that the proposed synthesis method is suitable for preparation of extremely fine CeO2 nanopowders and their nanocomposites with NPs. The morphology and magnetic nature of the obtained nanocomposites make them a promising candidate for magnetoresponsive catalysis.

  5. Independent versus non-independent outside directors in European companies: Who has a say on CEO compensation?

    Directory of Open Access Journals (Sweden)

    Pablo de Andrés

    2017-04-01

    Full Text Available Our study reveals how two separate dimensions of board composition—the proportion of independent directors and of non-independent directors—influence CEO compensation in Western European firms. Controlling for the simultaneous determination of CEO pay structure and board design, we find that firms with a higher proportion of non-independent outsiders on their boards pay less direct compensation (salary + bonus and less equity-linked compensation to their CEOs. By contrast, CEOs working for firms with more independent boards receive more equity based-pay. When we control for the fact that equity linked is not granted systematically in Europe we find that firms with more independent directors on the board tend to grant equity-linked compensation more often than firms with more non independent outside directors. Our results challenge the commonly accepted view of independent directors as safeguards of shareholder value, uncovering the relevance of non-independent outsiders for pay moderation and incentives.

  6. The Adoption of Internal Audit as a Governance Control Mechanism in Australian Public Universities--Views from the CEOs

    Science.gov (United States)

    Christopher, Joe

    2012-01-01

    This study draws on the multi-theoretical approach to governance and the views of university chief executive officers (CEOs) to examine the extent to which internal auditing as a control mechanism is adopted in Australian public universities under an environment of change management. The findings highlight negative consequences of change and their…

  7. Catalytic decomposition of N2O over CeO2 supported Co3O4 catalysts

    Indian Academy of Sciences (India)

    128, No. 11, November 2016, pp. 1795–1804. c Indian Academy of Sciences. DOI 10.1007/s12039-016-1180-3. Catalytic decomposition of N2O over CeO2 supported Co3O4 catalysts. S K MAHAMMADUNNISA, T AKANKSHA, K KRUSHNAMURTY and. CH SUBRAHMANYAM. ∗. Energy and Environmental Research Lab, ...

  8. Co3O4-CeO2 mixed oxide-based catalytic materials for diesel soot oxidation

    Czech Academy of Sciences Publication Activity Database

    Dhakad, M.; Mitshuhashi, T.; Rayalu, S.; Doggali, P.; Bakardjieva, Snejana; Šubrt, Jan; Fino, D.; Haneda, H.; Labhsetwar, N.

    2008-01-01

    Roč. 132, 1-4 (2008), s. 188-193 ISSN 0920-5861 R&D Projects: GA MŠk LC523 Institutional research plan: CEZ:AV0Z40320502 Keywords : soot oxidation * diesel particulate * Co3O4-CeO2 type mixed oxide Subject RIV: CA - Inorganic Chemistry Impact factor: 3.004, year: 2008

  9. Surprise! From CEOs to Navy Seals: How a Select Group of Professionals Prepare for and Respond to the Unexpected

    Science.gov (United States)

    2013-01-01

    and respond when a surprise occurs or something otherwise does start to go wrong.8 Both the test pilot and the medical practitioners also rely heav ...test pilot, October 24, 2012. 52 Surprise! From CEOs to Navy SEALs tance between the planets . If something catastrophic were to happen to a rover

  10. Relationship between CEO remuneration and company financial performance in the South African retail and consumer goods sector

    Directory of Open Access Journals (Sweden)

    Mark Bussin

    2015-04-01

    Full Text Available Purpose: This study was motivated by the need to better understand the effects of the global financial crisis in 2008 on the relationship between company financial performance and CEO guaranteed cost to company (CTC. The aim of this study was to understand the relationship between company financial performance using DuPont analysis and CEO guaranteed CTC in the South African retail and consumer goods sector. Design: The research was a quantitative, archival study of companies listed on the Johannesburg Stock Exchange (JSE, measured over a period of six years (2006–2011. The statistical analysis included regression and correlation analysis. Findings: The research found that CEO guaranteed CTC has shown no sensitivity towards company financial performance in terms of DuPont analysis over the six-year period, which included the global financial crises in 2008. Furthermore, a negative relationship existed between the return on equity and the guaranteed CTC of CEOs in the retail and consumer goods sector during this period. Practical implications: The findings suggest that there is misalignment between company strategy and performance and the guaranteed CTC of CEOs. A practical implication would be to have independent and competent remuneration committees ensuring alignment of the interests of a company with those of its leaders in this regard.

  11. Optical characterization of hydrogen-free CeO2 doped DLC films deposited by unbalanced magnetron sputtering

    International Nuclear Information System (INIS)

    Zhang Zhenyu; Zhou Hongxiu; Guo Dongming; Gao Hang; Kang Renke

    2008-01-01

    A novel kind of hydrogen-free CeO 2 doped diamond-like carbon (DLC) films with thickness of 180-200 nm were deposited on silicon by unbalanced magnetron sputtering. Reduced reflectance and increased lifetime are expected with respect to pure DLC films, making these coatings good candidates as optical protective coatings for IR windows and solar cells. X-ray photoelectron spectroscopy confirms that CeO 2 is formed within the DLC films. Auger electron spectroscopy exhibits that the C, O, and Ce elements distribute uniformly across the film thickness, and C element diffuses into the Si substrate at the interface between the substrate and film. AFM shows that nanoparticles with diameter of around 50 nm are formed on the surface of deposited films, whose surface roughness is in the range of 1.3-2.3 nm. Raman spectra show the CeO 2 doped DLC films are amorphous DLC films, and both the G frequency and relative intensity ratio I D /I G are higher than those of pure DLC films. The photoluminescence of CeO 2 doped DLC films is obviously more intense than that of a pure DLC film, which indicates a promising potential as optical protective films for solar cells and IR window

  12. Luminescent and morphological study of Sr2CeO4 blue phosphor prepared from oxalate precursors

    International Nuclear Information System (INIS)

    Ferrari, Jefferson L.; Pires, Ana M.; Serra, Osvaldo A.; Davolos, Marian R.

    2011-01-01

    Luminescent and morphological studies of Sr 2 CeO 4 blue phosphor prepared from cerium-doped strontium oxalate precursor are reported. Powder samples were prepared from 5 and 25 mol% Ce 3+ -doped strontium oxalate as well as from a mechanical mixture of strontium oxalate and cerium oxalate at a 4:1 ratio, respectively. All the samples were characterized by XRD, IR, PLS, and SEM. The luminescent and structural properties of the Sr 2 CeO 4 material are little affected by the SrCO 3 remaining from precursors. The Sr 2 CeO 4 material consists in one-dimensional chains of edge-sharing CeO 6 octahedra that are linked together by Sr 2+ ions. The carbonate ion might be associated with oxygen ions of the linear chain, and also with the oxygen atoms located in the equatorial position, which consequently affects the charge transfer bands between O 2- and Ce 4+ . As observed by SEM, the morphological changes are related to each kind of precursor and thermal treatment, along with irregular powder particles within the size range 0.5-2 μm.

  13. CeO2/Bi2WO6Heterostructured Microsphere with Excellent Visible-light-driven Photocatalytic Performance for Degradation of Tetracycline Hydrochloride.

    Science.gov (United States)

    Zhang, Fengjun; Zou, Shuang; Wang, Tianye; Shi, Yuxi; Liu, Peng

    2017-10-01

    CeO 2 /Bi 2 WO 6 heterostructured microsphere with excellent and stable photocatalytic activity for degradation tetracyclines was successfully synthesized via a facile solvothermal route. The photocatalytic experiments indicated that CeO 2 /Bi 2 WO 6 heterostructured microspheres exhibited enhanced photocatalytic activity compared to pure Bi 2 WO 6 in both the degradation of tetracycline hydrochloride (TCH) and rhodamine B (RhB) under visible-light irradiation. The 1CeO 2 /2Bi 2 WO 6 exhibited the best photocatalytic activity for degradation of TCH, reaching 91% after 60 min reaction. The results suggested that the particular morphological conformation of the microspheres resulted in smaller size and more uniform morphology so as to increase the specific surface area. Meanwhile, the heterojunction was formed by coupling CeO 2 and Bi 2 WO 6 in the as-prepared microspheres, so that the separation efficiency of photogenerated electrons and holes was dramatically improved and the lifetimes of charge carriers were prolonged. Hence, introduction of CeO 2 could significantly enhance the photocatalytic activity of CeO 2 /Bi 2 WO 6 heterostructured microspheres and facilitate the degradation of TCH. This work provided not only a principle method to synthesize CeO 2 /Bi 2 WO 6 with the excellent photocatalytic performance for actual produce, but also a excellent property of the photocatalyst for potential application in photocatalytic treatment of tetracyclines wastewater from pharmaceutical factory. © 2017 The American Society of Photobiology.

  14. Early cephalometric characteristics in Class III malocclusion

    Directory of Open Access Journals (Sweden)

    Vanessa Costa Farias

    2012-04-01

    Full Text Available OBJECTIVE: Early identification of craniofacial morphological characteristics allows orthopedic segmented interventions to attenuate dentoskeletal discrepancies, which may be partially disguised by natural dental compensation. To investigate the morphological characteristics of Brazilian children with Class III malocclusion, in stages I and II of cervical vertebrae maturation and compare them with the characteristics of Class I control patients. METHODS: Pre-orthodontic treatment records of 20 patients with Class III malocclusion and 20 control Class I patients, matched by the same skeletal maturity index and sex, were selected. The craniofacial structures and their relationships were divided into different categories for analysis. Angular and linear measures were adopted from the analyses previously described by Downs, Jarabak, Jacobson and McNamara. The differences found between the groups of Class III patients and Class I control group, both subdivided according to the stage of cervical vertebrae maturation (I or II, were assessed by analysis of variance (ANOVA, complemented by Bonferroni's multiple mean comparisons test. RESULTS: The analysis of variance showed statistically significant differences in the different studied groups, between the mean values found for some angular (SNA, SNB, ANB and linear variables (Co - Gn, N - Perp Pog, Go - Me, Wits, S - Go, Ar - Go. CONCLUSION: Assessed children displaying Class III malocclusion show normal anterior base of skull and maxilla, and anterior positioning of the mandible partially related to increased posterior facial height with consequent mandibular counterclockwise rotation.

  15. Improving the Efficiency of DASC by Adding CeO2/CuO Hybrid Nanoparticles in Water

    Science.gov (United States)

    Midhun Mohan, V.; Sajeeb, A. M.

    Solar energy is the abundantly available source of renewable energy with least impact on environment. Direct absorption solar collector (DASC) is the commonly used device to absorb heat directly from sun and make use of it for different heating applications. In the past, many experiments have been done to increase the efficiency of DASC using nanofluids. In this paper, an examination of solar collector efficiency for hybrid CeO2/CuO-water (0.1% by volume) nanofluid under various flow rates and proportions of CeO2/CuO nanoparticles is investigated. The experiments were conducted at flow rates spanning from 20cc/min to 100cc/min and with CeO2/CuO nanoparticles proportions of 1:0, 1:0.5, 1:1, 0.5:1 and 0:1. The efficiency increases from 16.5% to 51.6% when the flow rate is increased from 20cc/min to 100cc/min for hybrid CeO2/CuO (1:1)-water nanofluid. The results also showed an increase in efficiency of 13.8%, 18.1%, 24.3%, 24.9% and 26.1% with hybrid combination of CeO2/CuO at ratios 1:0, 1:0.5, 1:1, 0.5:1 and 0:1, respectively, in comparison with water at a flow rate of 100cc/min.

  16. Synthesis and physico-chemical characterization of CeO2/ZrO2-SO42- mixed oxides

    International Nuclear Information System (INIS)

    Hernandez E, J. M.; Silva R, R.; Garcia A, R.; Garcia S, L. A.; Handy, B. E.; Cardenas G, G.; Cueto H, A.

    2012-01-01

    Environmentally friendly solid-acid catalysts CeO 2 /ZrO 2 -SO 4 2- were prepared by the sol gel method varying CeO 2 content (10, 20 and 30 wt %) and using sulfation in situ, maintaining the sulfate ions amount present in the materials at 20 wt %. ZrO 2 and ZrO 2 -SO 4 2- were also prepared for comparison proposes using the same synthesis method. The materials were characterized by X-ray diffraction, nitrogen physisorption, potentiometric titration with n-butylamine, decomposition of 2-propanol and n-pentane isomerization. The specific surface area of ZrO 2 -SO 4 2- was high (160 m 2 /g) compared with the unmodified ZrO 2 (80 m 2 /g), however this area decreased with increasing the CeO 2 content (37-100 m 2 /g). There was no significant effect of CeO 2 on the tetragonal structure of ZrO 2 -SO 4 2- . The variation of acid sites amount runs parallel to the change of specific surface area. The acid sites amount decreased with increasing cerium oxide content. The decomposition of 2-propanol results fundamentally in the formation of dehydration products such as propylene and diisopropyl ether, both involving acid sites. In addition, a good performance during the n-pentane isomerization was observed for these materials. The selectivity towards isopentane reaches 84% when the Pt/CeO 2 /ZrO 2 -SO 4 2- catalyst with the highest CeO 2 content was used. (Author)

  17. Electrochemical impedance spectroscopy study during accelerated life test of conductive oxides: Ti/(Ru + Ti + Ce)O2-system

    International Nuclear Information System (INIS)

    Silva, Leonardo M. da; Fernandes, Karla C.; Faria, Luiz A. de; Boodts, Julien F.C.

    2004-01-01

    Ti-supported (Ru + Ti + Ce)O 2 -electrodes were prepared at 450d deg. C and the service life, t 6V , determined recording chronopotentiometric curves at 0.75Acm -2 (25 ± 1 deg. C). The results revealed a strong influence of the nominal cerium concentration, [CeO 2 ] N , on t 6V , showing substitution of Ti by Ce causes a major decrease in t 6V . The degree of electrode instability, Λ, calculated from the slope of the linear segment present in the chronopotentiometric profiles, showed [CeO 2 ] N exerts a strong influence on Λ. Voltammetric curves recorded at several anodisation times, t, support final electrode deactivation is due to Ti-support passivation. The chronopotentiometric and voltammetric data permitted to present a model for the porous electrode/electrolyte interface. The electrochemical impedance spectroscopic, EIS, investigation as function of t supports the proposed model denouncing a fast growth a TiO 2 interlayer at the Ti o /oxide interface for [CeO 2 ] N >= 30mol%. The studies also support substitution of Ti by Ce leads to an increase in the coating porosity, thus favouring electrode deactivation by passivation of the Ti-substrate. The model proposed for the porous electrode/electrolyte interface combined with the results of the EIS investigation permitted to propose an equivalent circuit to describe the modifications occurring in the electrode structure during anodisation. The true electrocatalytic activity for the oxygen evolution reaction, OER, depends on t and [CeO 2 ] N . The dependency of the inductive behaviour on t was investigated according to the model proposed for the effective inductance, L E , in the high frequency domain

  18. Faceting of (001) CeO2 Films: The Road to High Quality TFA-YBa2Cu3O7 Multilayers

    International Nuclear Information System (INIS)

    Coll, M; Gazquez, J; Sandiumenge, F; Pomar, A; Puig, T; Obradors, X; Espinos, J P; Gonzalez-Elipe, A R

    2006-01-01

    CeO 2 films are technologically important as a buffer layer for the integration of superconducting YBa 2 Cu 3 O 7 films on biaxially textured Ni substrates. The growth of YBa 2 Cu 3 O 7 layers on the CeO 2 cap layers by the trifluoroacetate (TFA) route remains a critical issue. To improve the accommodation of YBa 2 Cu 3 O 7 on CeO 2 , surface conditioning or CeO 2 is required. In this work we have applied ex-situ post-processes at different atmospheres to the CeO 2 layers deposited on YSZ single crystals using rf sputtering. XPS analysis showed that post-annealing CeO 2 layer in Ar/H 2 /H 2 O catalyses in an unexpected way the growth of (001)- terraces. We also report on the growth conditions of YBa 2 Cu 3 O 7 -TFA on CeO 2 buffered YSZ single crystal grown by chemical solution deposition and we compare them with those leading to optimized YBa 2 Cu 3 O 7 -TFA films on LaAlO 3 single crystals. Critical currents up to 1.6 MA/cm 2 at 77 K have been demonstrated in 300 nm thick YBa 2 Cu 3 O 7 layers on CeO 2 /YSZ system. The optimized processing conditions have then been applied to grow YBa 2 Cu 3 O 7 -TFA films on Ni substrates having vacuum deposited cap layers of CeO 2

  19. Environmentally friendly synthesis of CeO2 nanoparticles for the catalytic oxidation of benzyl alcohol to benzaldehyde and selective detection of nitrite

    Science.gov (United States)

    Tamizhdurai, P.; Sakthinathan, Subramanian; Chen, Shen-Ming; Shanthi, K.; Sivasanker, S.; Sangeetha, P.

    2017-04-01

    Cerium oxide nanoparticles (CeO2 NPs) are favorable in nanotechnology based on some remarkable properties. In this study, the crystalline CeO2 NPs are successfully prepared by an efficient microwave combustion (MCM) and conventional route sol-gel (CRSGM) methods. The structural morphology of the as-prepared CeO2 NPs was investigated by various spectroscopic and analytical techniques. Moreover, the XRD pattern confirmed the formation of CeO2 NPs as a face centered cubic structure. The magnetometer studies indicated the low saturation magnetization (23.96 emu/g) of CeO2 NPs for weak paramagnetic and high saturation magnetization (32.13 emu/g) of CeO2 NPs for super paramagnetic. After that, the oxidation effect of benzyl alcohol was investigated which reveals good conversion and selectivity. Besides, the CeO2 NPs modified glassy carbon electrode (GCE) used for the detection of nitrite with linear concentration range (0.02-1200 μM), low limit of detection (0.21 μM) and higher sensitivity (1.7238 μAμM-1 cm-2). However, the CeO2 NPs modified electrode has the fast response, high sensitivity and good selectivity. In addition, the fabricated electrode is applied for the determination of nitrite in various water samples. Eventually, the CeO2 NPs can be regarded as an effective way to enhance the catalytic activity towards the benzyl alcohol and nitrite.

  20. Environmentally friendly synthesis of CeO2 nanoparticles for the catalytic oxidation of benzyl alcohol to benzaldehyde and selective detection of nitrite.

    Science.gov (United States)

    Tamizhdurai, P; Sakthinathan, Subramanian; Chen, Shen-Ming; Shanthi, K; Sivasanker, S; Sangeetha, P

    2017-04-13

    Cerium oxide nanoparticles (CeO 2 NPs) are favorable in nanotechnology based on some remarkable properties. In this study, the crystalline CeO 2 NPs are successfully prepared by an efficient microwave combustion (MCM) and conventional route sol-gel (CRSGM) methods. The structural morphology of the as-prepared CeO 2 NPs was investigated by various spectroscopic and analytical techniques. Moreover, the XRD pattern confirmed the formation of CeO 2 NPs as a face centered cubic structure. The magnetometer studies indicated the low saturation magnetization (23.96 emu/g) of CeO 2 NPs for weak paramagnetic and high saturation magnetization (32.13 emu/g) of CeO 2 NPs for super paramagnetic. After that, the oxidation effect of benzyl alcohol was investigated which reveals good conversion and selectivity. Besides, the CeO 2 NPs modified glassy carbon electrode (GCE) used for the detection of nitrite with linear concentration range (0.02-1200 μM), low limit of detection (0.21 μM) and higher sensitivity (1.7238 μAμM -1 cm -2 ). However, the CeO 2 NPs modified electrode has the fast response, high sensitivity and good selectivity. In addition, the fabricated electrode is applied for the determination of nitrite in various water samples. Eventually, the CeO 2 NPs can be regarded as an effective way to enhance the catalytic activity towards the benzyl alcohol and nitrite.

  1. Synergistic Opportunities for the Geostationary Satellite Constellation: Status of the CEOS Activity

    Science.gov (United States)

    Al-Saadi, J. A.; Zehner, C.

    2012-12-01

    This talk will summarize activities of the Committee on Earth Observation Satellites (CEOS) Atmospheric Composition Constellation (ACC) to collaboratively advance the next generation of air quality monitoring from space. Over the past 2 years, CEOS ACC have developed a position paper describing the benefits to be derived from such collaboration. The resulting ACC recommendations were endorsed by CEOS in May 2011. We will discuss next steps toward implementing this vision, starting with a new 3-year CEOS Action in 2012. Several countries and space agencies are currently planning to launch geostationary Earth orbit (GEO) missions in 2017-2022 to obtain atmospheric composition measurements for characterizing anthropogenic and natural distributions of tropospheric ozone, aerosols, and their precursors. These missions include Europe's ESA Sentinel-4 with EUMETSAT IRS, the United States' NASA GEO-CAPE, Korea's ME/MEST/KARI GEMS, and Japan's JAXA GMAP-Asia. GEO observations offer a quantum advance in air quality monitoring from space by providing measurements many times per day. However, a single GEO satellite views only a portion of the globe. These satellites, positioned to view Europe, East Asia, and North America, will collectively provide hourly coverage of the industrialized Northern Hemisphere at similar spatial resolutions. Planned low Earth orbit (LEO) missions will provide complementary daily global observations. Observations from a single LEO satellite will overlap those from each GEO satellite once per day, providing a means for combining the GEO observations and a necessary perspective for interpreting global impacts of smaller scale processes. The EUMETSAT Metop series, NOAA/NASA JPSS series, and ESA Sentinel-5 Precursor and Sentinel-5 missions will each provide such daily overlap with the GEO missions. The Canadian PCW PHEMOS mission will make an additional unique suite of observations. PCW will provide quasi-geostationary coverage over the Arctic that

  2. Estrongiloidíase em pacientes com pênfigo foliáceo

    Directory of Open Access Journals (Sweden)

    José Tavares-Neto

    1991-09-01

    Full Text Available Em 30 pacientes com pênfigo foliáceo, a freqüência da estrongiloidíase foi de 40,0%, através de três exames de Baermann-Moraes. No "Hospital do Pênfigo", em Uberaba, as freqüências da estrongiloidíase nos funcionários (n = 14 e escolares (n = 47 da Escola-creche, anexa, também foram altas, respectivamente 35,7% e 23,4%. Em 7 (58,3 % das 12 amostras do solo, do jardim/pátio do "Hospital", foram observadas formas de vida livre do Strongyloides stercoralis. O fator ambiental e a predisposição dos pacientes foram associados à alta transmissão da estrongiloidíase.

  3. The development and the use of a climatic database for CEOS using the COADS dataset

    OpenAIRE

    Roy, Claude; Mendelssohn, R.

    1998-01-01

    La base de données COADS (Comprehensive Ocean-Atmosphere Dataset) a été sélectionnée par CEOS pour analyser la variabilité climatique des zones d'upwelling mondiales au cours des quarante dernières années. Cette base de données rassemble 100 millions d'observations météorologiques de surface collectées par les navires marchands et d'autres plates-formes sur les océans du monde entier. La couverture est mondiale et les premières données remontent à 1854. Les principaux biais rencontrés lors de...

  4. Non-Enzymatic Glucose Biosensor Based on CuO-Decorated CeO2 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Panpan Guan

    2016-08-01

    Full Text Available Copper oxide (CuO-decorated cerium oxide (CeO2 nanoparticles were synthesized and used to detect glucose non-enzymatically. The morphological characteristics and structure of the nanoparticles were characterized through transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. The sensor responses of electrodes to glucose were investigated via an electrochemical method. The CuO/CeO2 nanocomposite exhibited a reasonably good sensitivity of 2.77 μA mM−1cm−2, an estimated detection limit of 10 μA, and a good anti-interference ability. The sensor was also fairly stable under ambient conditions.

  5. Crustáceos asociados a macroalgas en Bajo Pepito, Isla Mujeres, Caribe mexicano

    Directory of Open Access Journals (Sweden)

    Concepción Campos Vázquez

    2000-06-01

    Full Text Available Como resultado de muestreos mensuales durante un año en Bajo Pepito, Isla Mujeres, Caribe mexicano, se presentan los crustáceos asociados a macroalgas recolectadas por buceo autónomo. Se hallaron un total de 148 organismos: tres ordenes, 11 familias, 18 géneros y 19 especies en nueve tipos de asociaciones. El orden con mayor abundacia fue Isopoda (112 seguido de Amphipoda (20 y Decapoda (16.Crustaceans associated with macroalgae were collected for one year by scuba diving in Bajo Pepito, Isla Mujeres, mexican Caribbean. A total of 148 organisms were found: three orders, 11 families, 18 genera and 19 species in nine types of associations. The order with highest abundance was Isopoda (112, followed by Amphipoda (20 and Decapoda (16.

  6. Far-infrared spectroscopic study of CeO2 nanocrystals

    Science.gov (United States)

    Popović, Z. V.; Grujić-Brojčin, M.; Paunović, N.; Radonjić, M. M.; Araújo, V. D.; Bernardi, M. I. B.; de Lima, M. M.; Cantarero, A.

    2015-01-01

    We present the far-infrared reflectivity spectra of 5 nm-sized pure and copper-doped Ce1- x Cu x O2- y ( x = 0; 0.01 and 0.10) nanocrystals measured at room temperature in the 50-650 cm-1 spectral range. Reflectivity spectra were analyzed using the factorized form of the dielectric function, which includes the phonon and the free carriers contribution. Four oscillators with TO energies of approximately 135, 280, 370, and 490 cm-1 were included in the fitting procedure. These oscillators represent local maxima of the CeO2 phonon density of states, which is also calculated using the density functional theory. The lowest energy oscillator represents TA(L)/TA(X) phonon states, which become infrared-active E u modes at the L and X points of the Brillouin zone (BZ). The second oscillator originates from TO(Γ) phonon states. The oscillator at 400 cm-1 originates from Raman mode phonon states, which at the L point of BZ also becomes infrared-active E u mode. The last oscillator describes phonons with dominantly LO(Γ) infrared mode character. The appearance of phonon density of states related oscillators, instead of single F 2uinfrared-active mode in the far-infrared reflectivity spectra, is a consequence of the nanosized dimension of the CeO2 particles. The best fit spectra are obtained using the generalized Bruggeman model for inhomogeneous media, which takes into account the nanocrystal volume fraction and the pore shape.

  7. Far-infrared spectroscopic study of CeO2 nanocrystals

    International Nuclear Information System (INIS)

    Popović, Z. V.; Grujić-Brojčin, M.; Paunović, N.; Radonjić, M. M.; Araújo, V. D.; Bernardi, M. I. B.; Lima, M. M. de; Cantarero, A.

    2015-01-01

    We present the far-infrared reflectivity spectra of 5 nm-sized pure and copper-doped Ce 1−x Cu x O 2−y (x = 0; 0.01 and 0.10) nanocrystals measured at room temperature in the 50–650 cm −1 spectral range. Reflectivity spectra were analyzed using the factorized form of the dielectric function, which includes the phonon and the free carriers contribution. Four oscillators with TO energies of approximately 135, 280, 370, and 490 cm −1 were included in the fitting procedure. These oscillators represent local maxima of the CeO 2 phonon density of states, which is also calculated using the density functional theory. The lowest energy oscillator represents TA(L)/TA(X) phonon states, which become infrared-active E u modes at the L and X points of the Brillouin zone (BZ). The second oscillator originates from TO(Γ) phonon states. The oscillator at ∼400 cm −1 originates from Raman mode phonon states, which at the L point of BZ also becomes infrared-active E u mode. The last oscillator describes phonons with dominantly LO(Γ) infrared mode character. The appearance of phonon density of states related oscillators, instead of single F 2u infrared-active mode in the far-infrared reflectivity spectra, is a consequence of the nanosized dimension of the CeO 2 particles. The best fit spectra are obtained using the generalized Bruggeman model for inhomogeneous media, which takes into account the nanocrystal volume fraction and the pore shape

  8. LEVANTAMENTO FAUNÍSTICO DOS CRUSTÁCEOS DECÁPODES (ANOMURA, BRACHYURA NO LITORAL CAPIXABA

    Directory of Open Access Journals (Sweden)

    Crislene Cristo Ribeiro

    2017-02-01

    Full Text Available Levantamento faunístico dos crustáceos decápodes é de fundamental importância para o conhecimento das comunidades, servindo de base para a conservação da biodiversidade. O objetivo deste estudo foi analisar a fauna dos Anomura e Brachyura em dois costões rochosos, localizados em Anchieta e Guarapari, litoral do Espírito Santo, com ênfase na análise dos índices de diversidade e similaridade entre as espécies. Em cada região, foram amostrados quatro pontos (P1, P2, P3 e P4, durante o período de outubro/2014 a setembro/2015. A diversidade de Shannon Wiener e equitabilidade foram calculados, bem como, o grau de semelhança entre as espécies. Foram coletados 3.156 indivíduos (1.022 em Anchieta e 2.134 em Guarapari, sendo representados por oito famílias e 14 espécies. O maior valor de diversidade foi encontrado no P1 e P2 em Anchieta, além do P1 ter apresentado o maior valor de equitabilidade. As espécies com abundância e ocorrência semelhantes foram agrupadas com maior similaridade. Os locais estudados apresentam condições favoráveis para o desenvolvimento e estabelecimento desses crustáceos anumuros e braquiúros.

  9. e-Collaboration for Earth observation (E-CEO): the Cloud4SAR interferometry data challenge

    Science.gov (United States)

    Casu, Francesco; Manunta, Michele; Boissier, Enguerran; Brito, Fabrice; Aas, Christina; Lavender, Samantha; Ribeiro, Rita; Farres, Jordi

    2014-05-01

    The e-Collaboration for Earth Observation (E-CEO) project addresses the technologies and architectures needed to provide a collaborative research Platform for automating data mining and processing, and information extraction experiments. The Platform serves for the implementation of Data Challenge Contests focusing on Information Extraction for Earth Observations (EO) applications. The possibility to implement multiple processors within a Common Software Environment facilitates the validation, evaluation and transparent peer comparison among different methodologies, which is one of the main requirements rose by scientists who develop algorithms in the EO field. In this scenario, we set up a Data Challenge, referred to as Cloud4SAR (http://wiki.services.eoportal.org/tiki-index.php?page=ECEO), to foster the deployment of Interferometric SAR (InSAR) processing chains within a Cloud Computing platform. While a large variety of InSAR processing software tools are available, they require a high level of expertise and a complex user interaction to be effectively run. Computing a co-seismic interferogram or a 20-years deformation time series on a volcanic area are not easy tasks to be performed in a fully unsupervised way and/or in very short time (hours or less). Benefiting from ESA's E-CEO platform, participants can optimise algorithms on a Virtual Sandbox environment without being expert programmers, and compute results on high performing Cloud platforms. Cloud4SAR requires solving a relatively easy InSAR problem by trying to maximize the exploitation of the processing capabilities provided by a Cloud Computing infrastructure. The proposed challenge offers two different frameworks, each dedicated to participants with different skills, identified as Beginners and Experts. For both of them, the contest mainly resides in the degree of automation of the deployed algorithms, no matter which one is used, as well as in the capability of taking effective benefit from a parallel

  10. Study of the defect structure of ''pure'' and doped nonstoichiometric CeO2

    International Nuclear Information System (INIS)

    Blumenthal, R.N.

    1975-09-01

    Electrical conductivity and thermogravimetric measurements were made on Ta 2 O 5 -doped nonstoichiometric CeO 2 (i.e. Ce/sub 1-y/Ta/sub y/O/sub 2-x/ ) as a function of temperature and oxygen partial pressure. Over a limited range of temperature and nonstoichiometry, the isothermal dependence of the electrical conductivity on nonstoichiometry may be described by the equation sigma = A + Bx, where A is the electronic conductivity associated with the electronic defects produced by doping CeO 2 with Ta 2 O 5 . The electronic conductivity resulting from the nonstoichiometric defect reaction O/sup x/ + 2Ce/sub Ce//sup x/ = V 0 + 2Ce'sub Ce/ + 1 / 2 O 2 (g) is equal to Bx. The ionic conductivity may be described by the relation sigma/sub i/ = B[y+x]eμ'/sub V 0 / exp (--E/sub i//kT), and the electronic conductivity by the isothermal expressions sigma/sub e/ proportional to P/sub O 2 //sup -1/4/ and sigma/sub e/ proportional to x; x less than 3 x 10 -2 . These results are consistent with defect models involving doubly ionized oxygen vacancies. An empirical expression (i.e. Δ anti H/sub O 2 / proportional to y/2 or z/4) was obtained relating the dependence of Δ anti H/sub O 2 / on the dopant concentration of lower valent foreign cations (e.g. y/2 for Ce/sub 1-y/M/sub y/O/sub 2-y-x/ and z/4 for Ce/sub 1-z/M/sub z/O/sub 2-z/2-x/ where M = Ca, Sr and M' = Y, La). (auth)

  11. Infrared and visible emissions of rare-earth-doped CeO2 phosphor.

    Science.gov (United States)

    Chandrakar, D; Kaur, J; Dubey, V; Suryanarayana, N S; Parganiha, Y

    2015-12-01

    This paper reports the synthesis and characterization of Er(3+)-doped CeO2 phosphor with variable concentrations of erbium. The sample was synthesized using a solid-state reaction method, which is useful for the large-scale production of phosphors and is also eco-friendly. The prepared sample was characterized using an X-ray diffraction (XRD) technique. The XRD pattern confirmed that sample has the pure cubic fluorite crystal structure of CeO2. The crystallite size of the prepared phosphor was determined by Scherer's formula and the crystallite size giving an intense XRD peak is 40.06 nm. The surface morphology of the phosphor was determined by field emission gun scanning electron microscopy (FEGSEM). From the FEGSEM image, good surface morphology with some agglomerates was found. The functional group in the prepared sample was analysed by Fourier transform infrared (FTIR) spectroscopy. All samples prepared with variable concentrations of Er(3+) (0.1-2 mol%) were studied by photoluminescence analysis and it was found that the excitation spectra of the prepared phosphor shows broad excitation centred at 251 nm. Emission spectra at different concentrations of Er(3+) show strong peaks at 413 and 470 nm and a weaker peak at 594 nm. The dominant peaks at 413 and 470 nm are caused by the allowed electronic transition (4)S3/2 → (4)I15/2 and the weaker transition at 594 nm is due to the transition (4)F9/2 → (4)I15/2. Spectrophotometric determinations of peaks were evaluated using the Commission Internationale de I'Eclairage (CIE) technique. The emission spectra were also observed using an infrared (IR) laser 980 nm source, and three distinct peaks were found in the IR region at 848, 870 and 980 nm. The prepared phosphor has utility for application in display devices. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Implementation and impact of in-class physical activities in a positive mental health perspective

    DEFF Research Database (Denmark)

    Christiansen, Lars Breum Skov; Holt, Anne-Didde; Smedegaard, Søren

    Introduction School physical activity and other activities with the body in focus hold the potential to benefit student’s positive mental health and psychosocial well-being. In-class activities (ICAs) (e.g. energizers, active breaks, brain breaks) can positively influence social connectedness...... intervention components in the RCT-designed ‘Move for well-being in school’ research program. The program comprises 2797 students 9-13 years old on 12 intervention schools and 12 comparison schools. During a full school year ICAs should be delivered two times every day focusing on four different aims: social...... interaction, energizing, coordination and wellness. A mixed methods design was used to evaluate the intervention comprising questionnaires and interviews with teachers and students. The collected data was used to assess the degree of implementation; perception of advantages and pitfalls of ICAs...

  13. Promoting Effect of CeO2 Addition on Activity and Catalytic Stability in Steam Reforming of Methane over Ni/Al2O3

    International Nuclear Information System (INIS)

    Rakib, A.; Gennequin, C.; Ringot, S.; Aboukais, A.; Abi-Aad, E.; Dhainaut, T.

    2011-01-01

    Hydrogen production by steam reforming of methane was studied over Ni catalysts supported on CeO 2 , Al 2 O 3 and CeO 2 -Al 2 O 3 . These catalysts were prepared using the impregnation method and characterized by XRD. The effect of CeO2 promoter on the catalytic performance of Ni/Al 2 O 3 catalyst for methane steam reforming reaction was investigated. In fact, CeO 2 had a positive effect on the catalytic activity in this reaction. Experimental results demonstrated that Ni/CeO 2 -Al 2 O 3 catalyst showed excellent catalytic activity and high reaction performance. In addition, the effects of reaction temperature and metal content on the conversion of CH 4 and H 2 /CO ratio were also investigated. Results indicated that CH4 conversion increased significantly with the increase of the reaction temperature and metal content. (author)

  14. Sonocatalytic and sonophotocatalytic activity of ternary Fe3O4/CeO2/ZnO for waste water removal

    Science.gov (United States)

    Harno, F. F.; Taufik, A.; Saleh, R.

    2017-07-01

    In this study, CeO2 nanoparticles were modified by Fe3O4 and ZnO to enhance their sono- and sonophotocatalytic activity for degrading Methylene Blue dye pollutant. The molar ratio between Fe3O4, CeO2, and ZnO was 0.05:1:1, 0.1:1:1, 0.3:1:1, 0.5:1:1. The ternary Fe3O4/CeO2/ZnO nanocomposites with various molar ratios were fabricated by the sol-gel method. The structure of ternary Fe3O4/CeO2/ZnO nanocomposites was investigated by XRD Diffraction, while the surface area was investigated by Brunauer-Emmett-Teller (BET). The conditions such as the molar ratio, catalyst dosage, and scavengers were investigated to see the degradation of Methylene Blue under ultrasonic and combination of ultrasonic and ultraviolet irradiations, simultaneously.

  15. Enhancement of photocatalytic properties of TiO2 nanoparticles doped with CeO2 and supported on SiO2 for phenol degradation

    International Nuclear Information System (INIS)

    Hao, Chunjing; Li, Jing; Zhang, Zailei; Ji, Yongjun; Zhan, Hanhui; Xiao, Fangxing; Wang, Dan; Liu, Bin; Su, Fabing

    2015-01-01

    Highlights: • CeO 2 -TiO 2 /SiO 2 composites were prepared via a facile co-precipitation method. • Introduction of SiO 2 support increases the dispersion of CeO 2 -TiO 2 . • CeO 2 -TiO 2 /SiO 2 exhibits an enhanced photocatalytic efficiency for phenol degradation. • Ce 3+ /Ce 4+ pair coexisting in CeO 2 improves electron–hole pairs separation efficiency. - Abstract: A series of CeO 2 -TiO 2 and CeO 2 -TiO 2 /SiO 2 composites were prepared with TiCl 4 and Ce (NO 3 ) 3 ·6H 2 O as precursors via a facile co-precipitation method. The obtained samples were characterized by various techniques such as X-ray diffraction (XRD), nitrogen adsorption (N 2 -BET), Fourier transformation infrared spectrum (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV–Vis spectroscopy measurements. The results indicated that TiO 2 doped with CeO 2 and supported on SiO 2 could reduce the crystallite size, inhibit the phase transformation, enhance the thermal stability, and effectively extend the spectral response from UV to visible range. When applied to the phenol photodegradation on a homemade batch reactor with an external cooling jacket, the CeO 2 -TiO 2 /SiO 2 catalysts exhibited significantly enhanced photodegradation efficiency in comparison with commercial Degussa P25 and CeO 2 -TiO 2 . The unique catalytic properties of CeO 2 -TiO 2 /SiO 2 were ascribed to improved electron–hole pairs separation efficiency and formation of more reactive oxygen species owing to the presence of Ce 3+ /Ce 4+ , as well as high dispersion of active component of CeO 2 -TiO 2 as a result of the introduction of SiO 2 support. Furthermore, the catalysts can be easily recovered from the reaction solution by centrifugation and reused for four cycles without significant loss of activity

  16. Hierarchical CeO2/Bi2MoO6 heterostructured nanocomposites for photoreduction of CO2 into hydrocarbons under visible light irradiation

    Science.gov (United States)

    Dai, Weili; Hu, Xu; Wang, Tengyao; Xiong, Wuwan; Luo, Xubiao; Zou, Jianping

    2018-03-01

    CeO2/Bi2MoO6 heterostructured microspheres with excellent and stable catalytic activity for CO2 photoreduction were successfully synthesized via a solvothermal route. The morphology, porosity, phase, chemical structure, optical and electronic properties of the as-prepared samples are characterized. It is observed that the CeO2/Bi2MoO6 nanocomposites with heterojunction showed greatly increased specific surface area, enhanced response to visible light, promoted charge carrier separation and transfer efficiency. Furthermore, the mechanism of CO2 photoreduction was also investigated. It demonstrates that the CO32-and HCO3- would be the reactive species, proving the thermodynamic feasibility of CO2 photoreduction. Notably, the presence of basic CeO2 on Bi2MoO6 surface dramatically enhances the adsorption ability of CO2, which could be further transferred into b-CO32-and b-HCO3- species as reactive intermediates for the photoreduction reaction. Consequently, introduction of CeO2 could significantly enhance the CO2 photoreduction performance of CeO2/Bi2MoO6 nanocomposites, attributing to the synergistic role of CeO2 as photosensitizer and CO2 adsorbent. The maximum total yield of CH3OH and C2H5OH was 58.4 μmol gcat-1 obtained over 5C-BM, which was about 1.9 and 4.1 times higher than that over pure Bi2MoO6 and pure CeO2. Moreover, the CeO2/Bi2MoO6 nanocomposites exhibit excellent chemical stability and recyclability.

  17. The hazard assessment of nanostructured CeO2-based mixed oxides on the zebrafish Danio rerio under environmentally relevant UV-A exposure

    International Nuclear Information System (INIS)

    Jemec, Anita; Djinović, Petar; Črnivec, Ilja Gasan Osojnik; Pintar, Albin

    2015-01-01

    The effect of nanomaterials on biota under realistic environmental conditions is an important question. However, there is still a lack of knowledge on how different illumination conditions alter the toxicity of some photocatalytic nanomaterials. We have investigated how environmentally relevant UV-A exposure (intensity 8.50 ± 0.61 W/m 2 , exposure dose 9.0 J/cm 2 ) affected the toxicity of cerium oxide (CeO 2 )-based nanostructured materials to the early-life stages of zebrafish Danio rerio. Pure cerium oxide (CeO 2 ), copper–cerium (CuO–CeO 2 ) (with a nominal 10, 15 and 20 mol.% CuO content), cerium–zirconium (CeO 2 –ZrO 2 ) and nickel and cobalt (Ni–Co) deposited over CeO 2 –ZrO 2 were tested. It was found that under both illumination regimes, none of the tested materials affected the normal development or induced mortality of zebrafish early-life stages up to 100 mg/L. Only in the case of CuO–CeO 2 , the growth of larvae was decreased (96 h LOEC values for CuCe10, CuCe15 and CuCe20 were 50, 50 and 10 mg/L, respectively). To conclude, CeO 2 -based nanostructured materials are not severely toxic to zebrafish and environmentally relevant UV-A exposure does not enhance their toxicity. - Highlights: • CeO 2 –ZrO 2 nanomaterials and pure CeO 2 (up to 100 mg/L) were not harmful to zebrafish. • Only CuO modified CeO 2 affected the growth of zebrafish larvae. • UV-A radiation did not enhance the toxicity of tested nanomaterials

  18. Stress response and tolerance of Zea mays to CeO2 nanoparticles: cross talk among H2O2, heat shock protein, and lipid peroxidation.

    Science.gov (United States)

    Zhao, Lijuan; Peng, Bo; Hernandez-Viezcas, Jose A; Rico, Cyren; Sun, Youping; Peralta-Videa, Jose R; Tang, Xiaolei; Niu, Genhua; Jin, Lixin; Varela-Ramirez, Armando; Zhang, Jian-ying; Gardea-Torresdey, Jorge L

    2012-11-27

    The rapid development of nanotechnology will inevitably release nanoparticles (NPs) into the environment with unidentified consequences. In addition, the potential toxicity of CeO(2) NPs to plants and the possible transfer into the food chain are still unknown. Corn plants (Zea mays) were germinated and grown in soil treated with CeO(2) NPs at 400 or 800 mg/kg. Stress-related parameters, such as H(2)O(2), catalase (CAT), and ascorbate peroxidase (APX) activity, heat shock protein 70 (HSP70), lipid peroxidation, cell death, and leaf gas exchange were analyzed at 10, 15, and 20 days post-germination. Confocal laser scanning microscopy was used to image H(2)O(2) distribution in corn leaves. Results showed that the CeO(2) NP treatments increased accumulation of H(2)O(2), up to day 15, in phloem, xylem, bundle sheath cells and epidermal cells of shoots. The CAT and APX activities were also increased in the corn shoot, concomitant with the H(2)O(2) levels. Both 400 and 800 mg/kg CeO(2) NPs triggered the up-regulation of the HSP70 in roots, indicating a systemic stress response. None of the CeO(2) NPs increased the level of thiobarbituric acid reacting substances, indicating that no lipid peroxidation occurred. CeO(2) NPs, at both concentrations, did not induce ion leakage in either roots or shoots, suggesting that membrane integrity was not compromised. Leaf net photosynthetic rate, transpiration, and stomatal conductance were not affected by CeO(2) NPs. Our results suggest that the CAT, APX, and HSP70 might help the plants defend against CeO(2) NP-induced oxidative injury and survive NP exposure.

  19. Design of MnO2/CeO2-MnO2hierarchical binary oxides for elemental mercury removal from coal-fired flue gas.

    Science.gov (United States)

    Ma, Yongpeng; Mu, Bailong; Yuan, Dongli; Zhang, Hongzhong; Xu, Haomiao

    2017-07-05

    MnO 2 /CeO 2 -MnO 2 hierarchical binary oxide was synthesized for elemental mercury (Hg 0 ) removal from coal-fired flue gas. CeO 2 in-situ grow on the surface of carbon spheres, and that CeO 2 @CSs acted as precursor for porous MnO 2 /CeO 2 -MnO 2 . XRD, Raman, XPS, FT-IR, and H 2 -TPR were selected for the physical structural and chemical surface analysis. The results indicated that the composite has sufficient surface oxygen and hierarchical porous structure. The Hg 0 removal experiments results indicated that MnO 2 /CeO 2 -MnO 2 exhibited excellent Hg 0 removal performance, with an 89% removal efficiency of total 300min at 150°C under 4% O 2 . MnO 2 was the primary active site for Hg 0 catalytic oxidation. The porous structure was beneficial for gaseous mercury physically adsorption. In addition, CeO 2 enhanced the oxygen capture performance of the composite and the oxidation performance for MnO 2 . Moreover, the effects of O 2 , SO 2 and H 2 O were also tested in this study. O 2 promoted the Hg 0 removal reaction. While SO 2 and H 2 O can poison the MnO 2 active site, resulted in a low Hg 0 removal efficiency. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Surface Reduced CeO2 Nanowires for Direct Conversion of CO2 and Methanol to Dimethyl Carbonate: Catalytic Performance and Role of Oxygen Vacancy

    Directory of Open Access Journals (Sweden)

    Zhongwei Fu

    2018-04-01

    Full Text Available Ultralong 1D CeO2 nanowires were synthesized via an advanced solvothermal method, surface reduced under H2 atmosphere, and first applied in direct synthesis of dimethyl carbonate (DMC from CO2 and CH3OH. The micro morphologies, physical parameters of nanowires were fully investigated by transmission electron microscopy (TEM, X-ray diffraction (XRD, N2 adsorption, X-ray photoelectron spectrum (XPS, and temperature-programmed desorption of ammonia/carbon dioxide (NH3-TPD/CO2-TPD. The effects of surface oxygen vacancy and acidic/alkaline sites on the catalytic activity was explored. After reduction, the acidic/alkaline sites of CeO2 nanowires can be dramatically improved and evidently raised the catalytic performance. CeO2 nanowires reduced at 500 °C (CeO2_NW_500 exhibited notably superior activity with DMC yield of 16.85 mmol gcat−1. Furthermore, kinetic insights of initial rate were carried out and the apparent activation energy barrier of CeO2_NW_500 catalyst was found to be 41.9 kJ/mol, much tiny than that of CeO2_NW catalyst (74.7 KJ/mol.

  1. A novel high-performance supercapacitor based on high-quality CeO2/nitrogen-doped reduced graphene oxide nanocomposite

    Science.gov (United States)

    Heydari, Hamid; Gholivand, Mohammad Bagher

    2017-03-01

    In this work, we have developed a novel nanocomposite via deposition of ceria (CeO2) on nitrogen-doped reduced graphene (CeO2/NRGO). NRGO was synthesized through a facile, safe, and scalable method to achieve simultaneous thermal reduction along with nitrogen doping of graphene oxide (GO) in air at much lower reaction temperature. CeO2/NRGO was prepared via a sonochemical method in which ceria nanoparticles were uniformly distributed on NRGO sheets. The structure and morphology of CeO2/NRGO nanocomposites were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), and Raman spectroscopy. Electrochemical properties of the proposed nanocomposite electrodes were investigated by cyclic voltammetry (CV), galvanostatic charge/discharge, continuous cyclic voltammetry (CCV), and electrochemical impedance spectroscopy (EIS) measurements. CeO2-NRGO nanocomposite electrodes showed excellent supercapacitive behavior, including much higher specific capacitance (230 F g-1 at 2 mV s-1) and higher rate capability compared to pure N-graphene. The cycling stability of the electrodes was measured by continues cyclic voltammetry (CCV) technique. The CCV showed that the specific capacitance of the CeO2/NRGO and NRGO nanocomposite maintained at 94.1 and 93.2% after 4000 cycles. The results suggest its promising potential as efficient electrode material for supercapacitors.

  2. Synthesis by Sol-gel and characterization of catalysts Ag/Al2O3-CeO2

    International Nuclear Information System (INIS)

    Zayas, M.L.; Perez H, R.; Rubio, E.; Velasco, A.

    2004-01-01

    Aluminia, cerium and mixed oxides Al 2 O 3 -CeO 2 with different relationship Al/Ce (0.75, 0.50 and 0.25) were prepared by sol-gel and used as support for the Ag. The samples were characterized by XRD, DRIFT, TPR and adsorption of N 2 to temperature of liquid nitrogen. The surface area BET showed that the materials that contain aluminia present near values among them. XRD allowed to identify to the cerianite in the oxides that whose support contains cerium and to the α-aluminia. A mixture of phases was observed in the aluminia. Vibration bands attributed to the bond Al-O and Ce-O were observed by DRIFT in the catalytic materials. TPR showed differences in the reducibility of the Ag precursor in the indicative catalysts of a different interaction with the support. (Author)

  3. Kinetic Monte Carlo model of defect transport and irradiation effects in La-doped CeO2

    International Nuclear Information System (INIS)

    Oaks, Aaron; Yun Di; Ye Bei; Chen Weiying; Stubbins, James F.

    2011-01-01

    A generalized Kinetic Monte Carlo code was developed to study oxygen mobility in UO 2 type nuclear fuels, using lanthanum doped CeO 2 as a surrogate material. Molecular Statics simulations were performed using interatomic potentials for CeO 2 developed by Gotte, Minervini, and Sayle to calculate local configuration-dependent oxygen vacancy migration energies. Kinetic Monte Carlo simulations of oxygen vacancy diffusion were performed at varying lanthanum dopant concentrations using the developed generalized Kinetic Monte Carlo code and the calculated configuration-dependent migration energies. All three interatomic potentials were found to confirm the lanthanum trapping effect. The results of these simulations were compared with experimental data and the Gotte potential was concluded to yield the most realistic diffusivity curve.

  4. Erosion behavior of HVOF thermal sprayed NiAl intermetallic coatings with different CeO2

    International Nuclear Information System (INIS)

    Wang, Y.; Chen, W.

    2003-01-01

    The influence of CeO 2 and heat treatment on the microstructure, hardness and especially erosion behavior of HVOF thermal sprayed NiAl intermetallic coatings was studied in this investigation. Among the NiAl intermetallic coatings studied, the NiAl coating containing 8 wt.% CeO 2 has the highest erosion rate, while the coating containing 2-5 wt.%CeO 2 exhibits the lowest erosion rate. Erosion surface morphologies showed a combined ductile and brittle feature. Heat treatment at temperatures higher than 600 o C softened the coating materials, leading to an increased erosion rate. Work hardening has occurred during erosion testing, and the highest degree of work hardening occurred in the NiAl coating containing about 5 wt.% CeO 2 . The degree of work hardening of the as-sprayed coating appeared larger than that of coating being heat-treated. Due to work hardening, the erosion rate becomes less discernible at the elongated erosion time among coatings with different hardness values. (author)

  5. Structural, optical and electrical properties of CeO2 thin films simultaneously prepared by anodic and cathodic electrodeposition

    Science.gov (United States)

    Yang, Yumeng; Du, Xiaoqing; Yi, Chenxi; Liu, Jiao; Zhu, Benfeng; Zhang, Zhao

    2018-05-01

    CeO2 thin films were deposited on stainless steel (SS) and indium tin oxide (ITO)-coated glass by simultaneous anodic and cathodic electrodeposition, and the influence of negative potential on the formation of ceria films was studied with scanning electron microscopy, X-ray diffraction, Raman spectroscopy, van der Pauw measurements, UV-visible spectroscopy and X-ray photoelectron spectroscopy. The results show that CeO2 films on the anode are slightly affected by the potential, but the particle size, crystal orientation, strain, film thickness, resistivity and Ce(III) content of the films on the cathode increases with increasing potential on the SS substrate. Contradictory to the results of the SS cathode, redshift (Ed changed from 3.95 eV to 3.56 eV and Ei changed from 3.42 eV to 3.04 eV) occurring in the absorption spectrum of CeO2 deposited on the ITO-coated glass cathode indicates that the content of Ce3+ in the cathodic films is dependent on the adopted substrates and decreases as the applied potential is increased.

  6. A comparative interlaboratory study on photocatalytic activity of commercial ZnO and CeO2 nanoparticles

    Science.gov (United States)

    Yin, Hong; Tsuzuki, Takuya; Millington, Keith R.; Casey, Philip S.

    2014-10-01

    Photocatalytic activity (PCA) was one of a number of physicochemical end points identified by the Organisation for Economic Cooperation and Development (OECD) as relevant to environmental safety and human health as part of their Sponsorship Programme for the Testing of Manufactured Nanomaterial. Photoactive surfaces can produce reactive oxygen species including free radicals which have the potential to cause oxidative stress in tissue or even oxidative damage to DNA. Here we report a study that involved three laboratories in Australia that independently characterised the PCA of commercially available ZnO and CeO2 NPs provided by the OECD programme. This inter-laboratory comparison found that PCA is a stable characteristic of NPs which was insensitive to variations in interlaboratory protocols and with ZnO NPs being more photoactive (by an order of magnitude) than CeO2 NPs. Comparisons were made between NPs of different sizes and the effect of the presence or absence of a surface coating on PCA. Because the competition between surface and volume effects determined PCA, a critical particle size was found for CeO2 NPs to achieve maximum PCA. The presence of a surface coating appeared to significantly mitigate, but not eliminate PCA.

  7. Effect of surface modification of CeO2 buffer layers on Jc and defect microstructures of large-area YBCO thin films

    International Nuclear Information System (INIS)

    Develos-Bagarinao, K; Yamasaki, H; Nakagawa, Y

    2006-01-01

    High-quality CeO 2 buffer layers are requisite for the successful growth of YBCO thin films with excellent properties on sapphire substrates. In this study, we evaluated the effect of surface modification of the CeO 2 layers on the properties of the YBCO thin films prepared by large-area pulsed laser deposition (PLD), in particular the critical current density J c and defect microstructure. High-temperature annealing (1050 deg. C ) has been found to significantly smoothen the very rough and granular surfaces of the as-grown CeO 2 layers (surface roughness rms∼5-10 nm) to atomic flatness (rms∼0.5 nm). However, a rather unique characteristic of the CeO 2 layers deposited by large-area PLD is the development of pores when subjected to prolonged high-temperature annealing. For very short annealing periods (10-20 min), the surface morphology becomes atomically flat, along with the appearance of a high density of 'nanopores' that are ∼40-100 nm in diameter and ∼3-5 nm in depth. Extending the annealing period to 60 min or more results in the development of a surface subtended with enlarged pores ∼0.2-0.5 μm in diameter. Compared with the YBCO thin films deposited on as-grown CeO 2 , YBCO thin films on annealed CeO 2 exhibited better homogeneity of J c and better crystalline texture. Among the YBCO thin films deposited on annealed CeO 2 , higher self-field and in-field J c was obtained for YBCO thin films deposited on CeO 2 with smooth surfaces but interspersed with nanopores. Investigation of the defect microstructure via the etch pit method in conjunction with atomic force microscopy (AFM) of the YBCO thin films revealed a high density of linear defects in the form of screw and edge dislocations, which correlated well with a high density of nanopores on annealed CeO 2 . Transmission electron microscopy (TEM) further confirmed the presence of threading dislocations clearly emanating from the nanopore sites. Angular dependence of J c revealed enhanced flux

  8. How much is CEO education worth to a firm? Evidence from European firms

    Directory of Open Access Journals (Sweden)

    Ottorino Morresi

    2017-09-01

    Full Text Available The emergence of an industry dedicated to evaluating the quality of university institutions around the world makes it possible to analyze whether students who graduate from highly-ranked schools perform better during their working lives. We focus on the education of CEOs who lead European listed firms, and analyze its impact on firm performance. If better schools produced better managers, we should find better firm performance for the firms led by managers who have graduated from highly-ranked schools. However, we do not find clear support for this claims, and rather our analysis shows that the ranking position of a university is not significantly linked to firm performance. Moreover, we find that the results of any such estimate are highly sensitive to the performance measure used and the type of ranking chosen. "QS University Rankings" and "Times Higher Education University Rankings" produce results that are more in line with our assumption. Unlike accounting ratios, market-based performance measures tend to provide stronger support for our hypothesis. JEL codes: G34; I26; J24

  9. The GOFC-GOLD/CEOS Land Cover Harmonization and Validation Initiative: Technical Design and Implementation

    Science.gov (United States)

    Herold, M.; Woodcock, C.; Stehman, S.; Nightingale, J.; Friedl, M.; Schmullius, C.

    2010-12-01

    A global effort to assess the accuracy of existing and future land cover products derived from a variety of satellite sensors over a range of spatial resolutions is being led by the Land Cover Implementation Team (LC-IT) of GOFC/GOLD (Global Observation of Land Cover Dynamics) in conjunction with the CEOS (Committee on Earth Observation Satellites) WGCV (Working Group on Calibration and Validation) LPV (Land Product Validation) subgroup. The first phase of this effort is complete and culminated in a publication of community consensus "best practices" for validation of global land cover datasets (2). The next phase is to implement the recommendations outlined in the "best practices" document. A "living database" of global randomized sample sites will form the basis of accuracy assessment for a host of global land cover products (GLC2000, MODIS land cover, GLOBCOVER, United Nation's Forest Resource Assessment (FRA2010), and the Mid-Decadal Global Land Survey. This "living dataset" will also be a community resource available for use in validation of regional or national mapping efforts using LCCS (UN FAO's Land Cover Classification System). Based on the known accuracy of existing land cover products, GOFC/GOLD will to develop and update a "best currently available" global land cover map. Individual geographic regions may be selected from different land cover products (global, national or regional), or they may be combined in various ways

  10. Structural and Raman Vibrational Studies of CeO2-Bi2O3 Oxide System

    Directory of Open Access Journals (Sweden)

    L. Bourja

    2009-01-01

    Full Text Available A series of ceramics samples belonging to the CeO2-Bi2O3 phase system have been prepared via a coprecipitation route. The crystallized phases were obtained by heating the solid precursors at 600∘C for 6 hours, then quenching the samples. X-ray diffraction analyses show that for x<0.20 a solid solution Ce1−xBixO2−x/2 with fluorine structure is formed. For x ranging between 0.25 and 0.7, a tetragonal β′ phase coexisting with the FCC solid solution is observed. For x ranging between 0.8 and 0.9, a new tetragonal β phase appears. The β′ phase is postulated to be a superstructure of the β phase. Finally, close to x=1, the classical monoclinic α Bi2O3 structure is observed. Raman spectroscopy confirms the existence of the phase changes as x varies between 0 and 1.

  11. Stability and Temperature-Induced Agglomeration of Rh Nanoparticles Supported by CeO2.

    Science.gov (United States)

    Varga, Erika; Pusztai, Péter; Oszkó, Albert; Baán, Kornélia; Erdőhelyi, András; Kónya, Zoltán; Kiss, János

    2016-03-22

    The effects of reduction by H2 and by heat treatment in vacuum and in O2 flow on Rh particle size changes of Rh/CeO2 samples were studied by X-ray photoelectron spectroscopy (XPS), high-resolution electron microscopy (HRTEM), and CO adsorption followed by diffuse reflectance infrared spectroscopy (DRIFTS). Low-temperature (373-423 K) reduction of Rh without agglomeration is demonstrated. An average particle size of 2.3 ± 1.1 nm was measured by HRTEM regardless of the metal loading (1-5%). On Rh/CeO2, a significant particle size increase of the Rh particles was detected on heating (773 K). In this work, we suggest that the temperature-induced surface decrease resulting from the sintering of Rh is favored only for well-dispersed particles. XP spectra revealed that the mobile oxygens of CeO2 fundamentally determine the oxidation state of the supported metals. At elevated temperature, the oxidation of the reduced support surface as well as the metal component takes place because of the segregation of ceria oxygens. When the aggregated particles were reoxidized, the redispersion of Rh was observed probably because of the formation of Rh-O-Ce bonds.

  12. The structure and catalytic properties of Rh-doped CeO2catalysts.

    Science.gov (United States)

    Derevyannikova, E A; Kardash, T Yu; Kibis, L S; Slavinskaya, E M; Svetlichnyi, V A; Stonkus, O A; Ivanova, A S; Boronin, A I

    2017-12-06

    The average structure and the local structure of nanocrystalline Rh-doped CeO 2 catalysts, prepared using a co-precipitation method, were studied using a set of structural (PDF, HRTEM, XRD) and spectral (XPS, Raman spectroscopy) methods. The samples with Rh content less than 10 wt%, calcined at 450 °C, were homogeneous solid solutions. A comparison of the experimental results and Pair distribution function (PDF) modeling data showed that Rh 3+ substitutes Ce 4+ ions in the fluorite phase. Charge equilibrium is obtained by the oxygen vacancy for each Rh 3+ cation introduced into the ceria cell. The solid solution demonstrated high catalytic activity in low-temperature CO oxidation (LTO CO). The solid solutions were stable only in a nanocrystalline state and decomposed upon thermal treatment. The calcination of the solid solution at T > 450 °C results in a decrease in the catalytic activity that is accompanied by Rh association in the subsurface area and strong distortion of the anionic subcell. At T = 800 °C α-Rh 2 O 3 nanoparticles are formed on the surface of the fluorite phase. The XRD-detectable Rh oxide phases are formed after calcination at 1000 °C. However, some parts of Rh within the subsurface Rh x Ce 1-x O 2-δ solid solution remain and they preserve catalytic properties for low-temperature oxidation.

  13. Estrongiloidíase em pacientes com pênfigo foliáceo

    Directory of Open Access Journals (Sweden)

    José Tavares-Neto

    1991-09-01

    Full Text Available Em 30 pacientes com pênfigo foliáceo, a freqüência da estrongiloidíase foi de 40,0%, através de três exames de Baermann-Moraes. No "Hospital do Pênfigo", em Uberaba, as freqüências da estrongiloidíase nos funcionários (n = 14 e escolares (n = 47 da Escola-creche, anexa, também foram altas, respectivamente 35,7% e 23,4%. Em 7 (58,3 % das 12 amostras do solo, do jardim/pátio do "Hospital", foram observadas formas de vida livre do Strongyloides stercoralis. O fator ambiental e a predisposição dos pacientes foram associados à alta transmissão da estrongiloidíase.In 30 patients with foliaceous pemphigus the frequency of strongyloidiasis was 40%, by three Baermann- Moraes examination. In the "Hospital do Penfigo", for patients with pemphigus of Uberaba, the frequencies of strongyloidiasis in the employees (n = 14 and students (n=47, of the annexed nursery, also were high, respectively 35.7 % and 23.4%. In 7(58.3 of 12 samples from the soil of the hospital courtyard were found free-life forms of Strongyloides. The environmental factor and the susceptibility of the pacients were associated with the high transmission of the strongyloidiasis.

  14. TEM investigation of irradiation damage in single crystal CeO2

    International Nuclear Information System (INIS)

    Ye Bei; Kirk, Mark A.; Chen, Weiying; Oaks, Aaron; Rest, Jeffery; Yacout, Abdellatif; Stubbins, James F.

    2011-01-01

    In order to understand the evolution of radiation damage in oxide nuclear fuel, 150-1000 keV Kr ions were implanted into single crystal CeO 2 , as a simulation of fluorite ceramic UO 2 , while in situ transmission electron microscopy (TEM) observations were carried out. Two characteristic defect structures were investigated: dislocation/dislocation loops and nano-size gas bubbles. The growth behavior of defect clusters induced by 1 MeV Kr ions up to doses of 5 x 10 15 ions/cm 2 were followed at 600 deg. C and 800 deg. C. TEM micrographs clearly show the development of defect structures: nucleation of dislocation loops, transformation to extended dislocation lines, and the formation of tangled dislocation networks. The difference in dislocation growth rates at 600 deg. C and 800 deg. C revealed the important role which Ce-vacancies play in the loop formation process. Bubble formation, studied through 150 keV Kr implantations at room temperature and 600 deg. C, might be influenced by either the mobility of metal-vacancies correlated with at threshold temperature or the limitation of gas solubility as a function of temperature.

  15. Factors Influencing Spanish Instructors' In-Class Feedback Decisions

    Science.gov (United States)

    Gurzynski-Weiss, Laura

    2016-01-01

    While oral corrective feedback is a principal focus in second language acquisition research, most studies examine feedback once it has been provided. Investigating how instructors make in-class feedback decisions has not been thoroughly explored, despite the fact that classroom feedback occurs at the discretion of the individual language…

  16. CeO2-TiO2 Photocatalyst: Ionic Liquid-Mediated Synthesis, Characterization, and Performance for Diisopropanolamine Visible Light Degradation

    Directory of Open Access Journals (Sweden)

    Jagath Retchahan Sivalingam

    2018-01-01

    Full Text Available CeO2-TiO2 photocatalyst with Ce:Ti molar ratio of 1:9 was synthesized via co-precipitation method in the presence of 1-ethyl-3-methyl imidazolium octylsulfate, [EMIM][OctSO4] (CeO2-TiO2-IL. The ionic liquid acts as a templating agent for particle growth. The CeO2-TiO2 and TiO2 photocatalysts were also synthesized without any ionic liquid for comparison. Calcination was conducted on the as-synthesized materials at 400˚C for 2 h. The photocatalysts were characterized using diffuse reflectance UV-Vis spectroscopy (DR-UV-Vis, field emission scanning electron microscopy (FESEM, X-ray powder diffraction (XRD, and surface area and pore size analyzer (SAP. The presence of CeO2 has changed the optical property of TiO2. It has extended the absorption edge of TiO2 from UV to visible region. The calculated band gap energy decreased from 2.82 eV (TiO2 to 2.30 eV (CeO2-TiO2-IL. The FESEM morphology showed that samples forms aggregates and the surface smoothens when ionic liquid was added. The average crystallite size of TiO2, CeO2-TiO2, and CeO2-TiO2-IL were 20.8 nm, 5.5 nm, and 4 nm. In terms of performance, photodegradation of 1000 ppm of diisopropanolamine (DIPA was conducted in the presence of hydrogen peroxide (H2O2 and visible light irradiation which was provided by a 500 W halogen lamp. The best performance was displayed by CeO2-TiO2-IL calcined at 400˚C. It was able to remove 82.0% DIPA and 54.8% COD after 6 h reaction.  Copyright © 2018 BCREC Group. All rights reserved Received: 26th July 2017; Revised: 22nd October 2017; Accepted: 29th October 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018 How to Cite: Sivalingam, J.R., Kait, C.F., Wilfred, C.D. (2018. CeO2-TiO2 Photocatalyst: Ionic Liquid-Mediated Synthesis, Characterization, and Performance for Diisopropanolamine Visible Light Degradation. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1: 170-178 (doi:10.9767/bcrec.13.1.1396.170-178

  17. Sm doped mesoporous CeO2 nanocrystals: aqueous solution-based surfactant assisted low temperature synthesis, characterization and their improved autocatalytic activity.

    Science.gov (United States)

    Mandal, Bappaditya; Mondal, Aparna; Ray, Sirsendu Sekhar; Kundu, Amar

    2016-01-28

    Mesoporous Sm(3+) doped CeO2 (Ce-Sm) with a nanocrystalline framework, a high content of Ce(3+) and surface area (184 m(2) g(-1)), have been synthesized through a facile aqueous solution-based surfactant assisted route by using inorganic precursors and sodium dodecyl sulphate as a template. The XRD results indicate that the calcined Ce-Sm and even the as-prepared material have a cubic fluorite structure of CeO2 with no crystalline impurity phase. XRD studies along with HRTEM results confirmed the formation of mesoporous nanocrystalline CeO2 at a lower temperature as low as 100 °C. A detailed analysis revealed that Sm(3+) doping in CeO2 has increased the lattice volume, surface area, mesopore volume and engineered the surface defects. Higher concentrations of Ce(3+) and oxygen vacancies of Ce-Sm resulted in lowering of the band gap. It is evident from the H2-TPR results that Sm(3+) doping in CeO2 strongly modified the reduction behavior of CeO2 by shifting the bulk reduction at a much lower temperature, indicating increased oxygen mobility in the sample which enables enhanced oxygen diffusion at lower temperatures, thus promoting reducibility, i.e., the process of Ce(4+)→ Ce(3+). UV-visible transmission studies revealed improved autocatalytic performance due to easier Ce(4+)/Ce(3+) recycling in the Sm(3+) doped CeO2 nanoparticles. From the in vitro cytotoxicity of both pure CeO2 and Sm(3+) doped CeO2 calcined at 500 °C in a concentration as high as 100 μg mL(-1) (even after 120 h) on MG-63 cells, no obvious decrease in cell viability is observed, confirming their excellent biocompatibility. The presence of an increased amount of surface hydroxyl groups, mesoporosity, and surface defects have contributed towards an improved autocatalytic activity of mesoporous Ce-Sm, which appear to be a potential candidate for biomedical (antioxidant) applications.

  18. Synthesis and Characterization of CeO2-SiO2 Nanoparticles by Microwave-Assisted Irradiation Method for Photocatalytic Oxidation of Methylene Blue Dye

    Directory of Open Access Journals (Sweden)

    R. M. Mohamed

    2012-01-01

    Full Text Available CeO2-SiO2 nanoparticles were synthesized for the first time by a facile microwave-assisted irradiation process. The effect of irradiation time of microwave was studied. The materials were characterized by N2 adsorption, XRD, UV-vis/DR, and TEM. All solids showed mesoporous textures with high surface areas, relatively small pore size diameters, and large pore volume. The X-ray diffraction results indicated that the as-synthesized nanoparticles exhibited cubic CeO2 without impurities and amorphous silica. The transmission electron microscopy (TEM images revealed that the particle size of CeO2-SiO2 nanoparticles, which were prepared by microwave method for 30 min irradiation times, was around 8 nm. The photocatalytic activities were evaluated by the decomposition of methylene blue dye under UV light irradiations. The results showed that the irradiation under the microwave produced CeO2-SiO2 nanoparticles, which have the best crystallinity under a shorter irradiation time. This indicates that the introduction of the microwave really can save energy and time with faster kinetics of crystallization. The sample prepared by 30 min microwave irradiation time exhibited the highest photocatalytic activity. The photocatalytic activity of CeO2-SiO2 nanoparticles, which were prepared by 30 min irradiation times was found to have better performance than commercial reference P25.

  19. Synthesis of nano-sized ceria (CeO2 particles via a cerium hydroxy carbonate precursor and the effect of reaction temperature on particle morphology

    Directory of Open Access Journals (Sweden)

    Majid Farahmandjou

    2015-06-01

    Full Text Available Cerium oxide (CeO2 or ceria has been shown to be an interesting support material for noble metals in catalysts designed for emission control, mainly due to its oxygen storage capacity. Ceria nanoparticles were prepared by precipitation method. The precursor materials used in this research were cerium nitrate hexahydrate (as a basic material, potassium carbonate and potassium hydroxide (as precipitants. The morphological properties were characterized by high resolution transmission electron microscopy (HRTEM, scanning electron microscopy (SEM and X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR and UV-Vis spectrophotometer. XRD results showed face centered cubic CeO2 nanoparticles for annealed nanoparticles at 1000°C. SEM measurement showed that by increasing the calcinations temperature from 200 to 600°C, the crystallite size decreased from 90 to 28 nm. The SEM results showed that the size of the CeO2 nanoparticles decreased with increasing temperature. The particle size of CeO2 was around 25 nm as estimated by XRD technique and direct HRTEM observation. SEM and TEM studies showed that the morphology of the prepared powder was sphere-like with a narrow size distribution. The sharp peaks in FTIR spectrum determined the purity of CeO2 nanoparticles and absorbance peak of UV-Vis spectrum showed the small band gap energy of 3.26 ev.

  20. Adsorption mechanism and kinetics of azo dye chemicals on oxide nanotubes: a case study using porous CeO2 nanotubes

    Science.gov (United States)

    Wu, Junshu; Wang, Jinshu; Du, Yucheng; Li, Hongyi; Jia, Xinjian

    2016-07-01

    Metal oxide nanotubes are believed to be promising materials with adsorption functionality for water purification due to their synergistic effect of the overall microscale morphology for easy separation and nanoscale surface characters providing enough surface active absorption sites. This work shows the synthesis of uniform hierarchical porous CeO2 nanotubes via nanowire-directed templating method and describes the adsorption behavior of CeO2 nanotubes for a typical azo dye Congo red which has resistance to oxidation and decoloration in natural conditions. Fourier transform infrared spectroscopy spectra provided the evidence that Congo red was successfully coated on the surface of CeO2 nanotubes by both bidentate-type bridge link of Ce4+ cations from sulfonate SO3 - groups and the electrostatic attraction between the protonated surface generated by oxygen vacancies and dissociated sulfonate groups. The adsorption kinetic data fitted well to the pseudo-second-order kinetic equation, whereas the Langmuir isotherm equation exhibited better correlation with the experimental data. The calculated maximum adsorption capacity from the isothermal model was 362.32 mg/g. In addition, the prepared CeO2 nanotubes exhibited good recyclability and reusability as highly efficient adsorbents for Congo red removal after regeneration. These favorable performances enable the obtained CeO2 nanotubes to be promising materials for dye removal from aqueous solution.

  1. Examination of oxygen vacancy formation in Mn-doped CeO2 (111) using DFT+U and the hybrid functional HSE06.

    Science.gov (United States)

    Krcha, Matthew D; Janik, Michael J

    2013-08-13

    MnO(x)-CeO(x) mixed oxide systems exhibit interesting sulfur adsorption capacities and catalytic activity. We examined the electronic structure of Mn-doped fluorite CeO2 bulk solid and surface using density functional theory (DFT) with the Hubbard U term or the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional. We specifically evaluate the reducibility and formation energies of Mn-doped CeO2 surfaces. The use of a U value on the d-states of Mn is examined, and a value of 4 eV is chosen based upon results from DFT+U calculations on bulk MnO(x),1 XANES characterization of oxidation states in calcined and reduced Mn-doped CeO2, and comparison with HSE06 hybrid functional results. Electronic structure impacts of the U inclusion are discussed. The concentration and orientation of Mn atoms doped into the surface of CeO2 have a great influence on the reducibility of the surface. Based upon formation energies, Mn will not favor doping into the surface of CeO2 in a fully oxidized system (Mn(4+)). Under reducing environments, Mn will dope into the surface with oxygen vacancies present (Mn(3+) and Mn(2+)). The first oxygen vacancy is not likely catalytically important in fluorite MnO(x)-CeO(x) systems as formation of the fully oxidized surface is not stable. A greater degree of reduction would occur during a catalyzed redox reaction.

  2. Generación controlada de nanocoloides de plata en materiales silíceos amorfos

    Directory of Open Access Journals (Sweden)

    Gil, C.

    2004-04-01

    Full Text Available Amorphous silica-based materials bulk and superficially doped with silver nanocolloids were prepared. Bulk doped glasses were obtained by conventional melting and doped monolithic slabs by sol-gel. Superficially doped glasses were obtained by ion-exchange and doped coatings by sol-gel. The samples were characterised by TEM and UV-VIS spectrophotometry. Depending on the composition, the silver incorporation process, and the thermal treatments, several colourings were obtained. By controlling these parameters, metallic silver nanocolloids can be generated in the matrices studied. Colloids aggregation and growing up depends on the matrix nature and on the experimental process carried out.

    Se prepararon materiales silíceos amorfos dopados con nanocoloides de plata en masa y en superficie. Se obtuvieron vidrios dopados en masa por fusión convencional y láminas monolíticas dopadas por sol-gel. Asimismo se prepararon vidrios dopados superficialmente por cambio iónico y recubrimientos dopados por sol-gel. Los materiales se caracterizaron por MET y espectrofotometría UV-VIS. Dependiendo de la composición del material, del proceso de incorporación de la plata y de los tratamientos térmicos, se obtuvieron diferentes coloraciones. El control de estas variables permitió generar nanocoloides metálicos de plata en las matrices estudiadas. La agregación y crecimiento de los coloides depende de la naturaleza de la matriz y del proceso experimental utilizado.

  3. Utility of regional satellite volcano deformation monitoring in Latin America: The CEOS pilot project

    Science.gov (United States)

    Delgado, F.; Pritchard, M. E.; Biggs, J.; Arnold, D.

    2014-12-01

    Satellite observations are a cost effective tool for monitoring large numbers of volcanoes in areas with scarce instrumentation or difficult access. In the context of the 2012 Santorini Report on satellite Earth Observation and Geohazards, CEOS (Committee on Earth Observation Satellites) has developed a pilot project to showcase remote sensing for volcano hazard mitigation and response. Specifically, the pilot aims to demonstrate the feasibility of global volcano monitoring of Holocene volcanoes by undertaking regional monitoring of volcanic arcs in Latin America, using satellite earth observations data to track deformation as well as gas, ash, and thermal emissions. Latin America was chosen because the volcanoes are situated in a diversity of environments, providing a good test of the capabilities of different types of satellite data under different conditions; volcanic activity is abundant, and monitoring agencies in Latin American countries would directly benefit from the resources that this pilot will make available. It is hoped that the regional study will demonstrate that Earth observation data can help to identify volcanoes that may become active in the future as well as track eruptive activity that may impact populations and infrastructure on the ground and in the air, ultimately leading to improved targeting for permanent satellite-based observations and in-situ volcanic monitoring efforts. The pilot project is posible thanks to data provided by the various space agencies (ESA, ASI, DLR, JAXA, NASA, CNES, CSA). In this contribution, we focus on premilinary ground deformation results using SAR satellites for selected areas in the Northern and Southern Andes as well as the Caribbean with recent unrest. For example, in the Southern Andes we will present ALOS time series at Llaima (-38.7 S) and Peteroa (-35.2 S) volcanoes, both of which have had eruptions during the past ten years.

  4. Linking space observations to volcano observatories in Latin America: Results from the CEOS DRM Volcano Pilot

    Science.gov (United States)

    Delgado, F.; Pritchard, M. E.; Biggs, J.; Arnold, D. W. D.; Poland, M. P.; Ebmeier, S. K.; Wauthier, C.; Wnuk, K.; Parker, A. L.; Amelug, F.; Sansosti, E.; Mothes, P. A.; Macedo, O.; Lara, L.; Zoffoli, S.; Aguilar, V.

    2015-12-01

    Within Latin American, about 315 volcanoes that have been active in the Holocene, but according to the United Nations Global Assessment of Risk 2015 report (GAR15) 202 of these volcanoes have no seismic, deformation or gas monitoring. Following the 2012 Santorini Report on satellite Earth Observation and Geohazards, the Committee on Earth Observation Satellites (CEOS) has developed a 3-year pilot project to demonstrate how satellite observations can be used to monitor large numbers of volcanoes cost-effectively, particularly in areas with scarce instrumentation and/or difficult access. The pilot aims to improve disaster risk management (DRM) by working directly with the volcano observatories that are governmentally responsible for volcano monitoring, and the project is possible thanks to data provided at no cost by international space agencies (ESA, CSA, ASI, DLR, JAXA, NASA, CNES). Here we highlight several examples of how satellite observations have been used by volcano observatories during the last 18 months to monitor volcanoes and respond to crises -- for example the 2013-2014 unrest episode at Cerro Negro/Chiles (Ecuador-Colombia border); the 2015 eruptions of Villarrica and Calbuco volcanoes, Chile; the 2013-present unrest and eruptions at Sabancaya and Ubinas volcanoes, Peru; the 2015 unrest at Guallatiri volcano, Chile; and the 2012-present rapid uplift at Cordon Caulle, Chile. Our primary tool is measurements of ground deformation made by Interferometric Synthetic Aperture Radar (InSAR) but thermal and outgassing data have been used in a few cases. InSAR data have helped to determine the alert level at these volcanoes, served as an independent check on ground sensors, guided the deployment of ground instruments, and aided situational awareness. We will describe several lessons learned about the type of data products and information that are most needed by the volcano observatories in different countries.

  5. Cyberinfrastructure Initiatives of the Committee on Earth Observation Satellites (CEOS) Working Group on Information Systems and Services (WGISS)

    Science.gov (United States)

    McDonald, K. R.; Faundeen, J. L.; Petiteville, I.

    2005-12-01

    The Committee on Earth Observation Satellites (CEOS) was established in 1984 in response to a recommendation from the Economic Summit of Industrialized Nations Working Group on Growth, Technology, and Employment's Panel of Experts on Satellite Remote Sensing. CEOS participants are Members, who are national or international governmental organizations who operate civil spaceborne Earth observation satellites, and Associates who are governmental organizations with civil space programs in development or international scientific or governmental bodies who have an interest in and support CEOS objectives. The primary objective of CEOS is to optimize benefits of satellite Earth observations through cooperation of its participants in mission planning and in development of compatible data products, formats, services, applications and policies. To pursue its objectives, CEOS establishes working groups and associated subgroups that focus on relevant areas of interest. While the structure of CEOS has evolved over its lifetime, today there are three permanent working groups. One is the Working Group on Calibration and Validation that addresses sensor-specific calibration and validation and geophysical parameter validation. A second is the Working Group on Education, Training, and Capacity Building that facilitates activities that enhance international education and training in Earth observation techniques, data analysis, interpretation and applications, with a particular focus on developing countries. The third permanent working group is the Working Group on Information Systems and Services (WGISS). The purpose of WGISS is to promote collaboration in the development of the systems and services based on international standards that manage and supply the Earth observation data and information from participating agencies' missions. WGISS places great emphasis on the use of demonstration projects involving user groups to solve the critical interoperability issues associated with the

  6. Toxicity of CeO2 nanoparticles at different trophic levels--effects on diatoms, chironomids and amphibians.

    Science.gov (United States)

    Bour, Agathe; Mouchet, Florence; Verneuil, Laurent; Evariste, Lauris; Silvestre, Jérôme; Pinelli, Eric; Gauthier, Laury

    2015-02-01

    The aim of the present work is to provide wider information on the toxicity of cerium dioxide nanoparticles (CeO2 NPs) in aquatic environments, by studying the toxicity of two types of CeO2 NPs for four species (diatoms Nitzschia palea, the sediment-dwelling invertebrate Chironomus riparius, and the amphibian larvae Xenopus laevis and Pleurodeles waltl.). The two types of CeO2 NPs have different intrinsic properties: some of them are small citrate-coated spheres (2-5 nm), and the others are larger uncoated plates (20-60 nm). Acute toxicity (mortality at 48 or 96 h, depending on the test-organism) was assessed for the four species, from 0.1 to 100 mg L(-1) of NPs. Sub-lethal effects were assessed on chironomids exposed between 0.01 and 1 mg L(-1) of NPs. Mortality, growth inhibition and genotoxic effects were evaluated on amphibian larvae from 0.1 to 10 mg L(-1). Results reveal that no acute toxicity occurs on any species after short exposures, even at the highest concentrations. Mortality (35%) is observed on Xenopus larvae after 12d of exposure at the highest concentration of one type of NPs. No significant effects were observed on chironomids during chronic exposure. Xenopus larvae growth was inhibited from 1 mg L(-1) of both NPs while growth inhibition is observed on Pleurodeles only at the highest concentration of one type of NPs. No genotoxicity was observed on Xenopus but Pleurodeles exhibited dose-dependent genotoxic effects when exposed to one type of NPs. Observed differences in toxicity are discussed focusing on the studied compartment, routes of exposure, species and NPs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. ¿Es necesario disponer de tratamientos con buprenorfina/naloxona para los presos dependientes de opiáceos?

    Directory of Open Access Journals (Sweden)

    A. Marco

    Full Text Available La utilización de programas de tratamiento con agonistas opiáceos (TAO, junto con un abordaje psicosocial, es la forma más efectiva de prevenir recaídas en los pacientes con dependencia a opiáceos. Estos programas disminuyen la morbimortalidad así como las conductas de riesgo de transmisión del VIH y de otras infecciones, mejoran la calidad de vida y la retención en tratamiento, y tienen un impacto positivo sobre los comportamientos asociales, por lo que son muy útiles en presos con antecedente de consumo de opiáceos. Los TAO basados en el uso de buprenorfina/naloxona (B/N, igual que los basados en metadona (MT, están actualmente disponibles en España. El tratamiento diversificado ofrece una alternativa de tratamiento para la dependencia de opioides más individualizada y adaptada a las características de los pacientes. En cuanto a eficacia ambos fármacos son muy similares, pero B/N es más segura, con menor perfil de interacciones con posibilidad de dispensación en farmacias una vez que el paciente sea puesto en libertad, lo que puede ayudar a la reintegración social. Económicamente, el tratamiento con B/N es más costoso que el de MT. Se aconseja disponer de las diferentes modalidades de TAO y que estas se prescriban según las características y necesidades de cada caso, sin que la reclusión menoscabe el derecho al tratamiento farmacológico, que debe ser similar al efectuado extrapenitenciariamente.

  8. Emission and Performance Analysis of ZrO2 And CeO2 Coated Piston Using Refined Vegetable Oils

    Science.gov (United States)

    Hemanandh, J.; Narayanan, K. V.; Manoj, Vemuri

    2017-05-01

    Increase in global warming and pollution leads to look for an alternative fuel. The aim of this paper to improve the performance and to reduce the emissions in DI diesel engine. The 80% of ZrO2 and 20% of CeO2 were mixed and coated on the piston head using plasma spray method. The B10 fuel of various refined vegetable oil methyl esters were used as fuel. The test was conducted in the 4-stroke DI diesel engine at a constant speed of 1500 rpm. The results show that the brake thermal efficiency, NOx and BSFC was increased. The CO and HC were decreased.

  9. Mindfulness Interventions.

    Science.gov (United States)

    Creswell, J David

    2017-01-03

    Mindfulness interventions aim to foster greater attention to and awareness of present moment experience. There has been a dramatic increase in randomized controlled trials (RCTs) of mindfulness interventions over the past two decades. This article evaluates the growing evidence of mindfulness intervention RCTs by reviewing and discussing (a) the effects of mindfulness interventions on health, cognitive, affective, and interpersonal outcomes; (b) evidence-based applications of mindfulness interventions to new settings and populations (e.g., the workplace, military, schools); (c) psychological and neurobiological mechanisms of mindfulness interventions; (d) mindfulness intervention dosing considerations; and (e) potential risks of mindfulness interventions. Methodologically rigorous RCTs have demonstrated that mindfulness interventions improve outcomes in multiple domains (e.g., chronic pain, depression relapse, addiction). Discussion focuses on opportunities and challenges for mindfulness intervention research and on community applications.

  10. Mineralization of volatile organic compounds (VOCs) over the catalyst CuO-Co3O4-CeO2 and its applications in industrial odor control

    KAUST Repository

    Somekawa, Shouichi

    2011-12-01

    Volatile organic compounds (VOCs) present at ppm levels were decomposed over the catalyst CuO-Co3O4-CeO2 (Cu:Co:Ce = 10:45:45 in mol) in an attempt to scale up for industrial odor control. In addition to enhancing the catalytic activity, CuO-Co3O4 and CeO2 helped, respectively, to maintain the strength of the pelleted catalysts and inhibit their sintering. Using toluene as a VOC model compound, kinetic analysis of the total oxidation to carbon dioxide was conducted. The odor emitted from paint-drying processes could be eliminated effectively using CuO-Co3O4-CeO2 (Cu:Co:Ce = 10:45:45) pelleted catalysts (188 ml) in a large-scale system. © 2011 Elsevier B.V. All rights reserved.

  11. Fabrication of Ni-5 at. %W Long Tapes with CeO2 Buffer Layer by Reel-to-Reel Method

    DEFF Research Database (Denmark)

    Ma, Lin; Tian, Hui; Yue, Zhao

    2015-01-01

    A 10-m-long homemade textured Ni-5at.%W (Ni5W) long tape with a CeO2 buffer layer has been prepared successfully by means of rolling-assisted biaxially textured substrate (RABiTS) route followed by a chemical solution deposition method in a reel-to-reel manner. Globally, the Ni5W substrate and CeO2...... film exhibit high homogeneity in terms of biaxial texture over the tape. The average values of full width at half maximum of in-plane and out-of-plane texture are 7.2° and 6.1° in Ni5W substrate, 7.6° and 6.1° in CeO2 buffer layer, respectively, all of those with a small standard deviation...

  12. Removals of aqueous sulfur dioxide and hydrogen sulfide using CeO2-NiAl-LDHs coating activated carbon and its mix with carbon nano-tubes

    KAUST Repository

    Li, Jing

    2015-07-01

    Ce-doped NiAl/layered double hydroxide was coated at activated carbon by urea hydrolysis method (CeO2-NiAl-LDHs/AC) in one pot, which was characterized by X-ray diffraction, infrared spectra, field emission scanning electron microscope and electrochemical techniques. CeO2-NiAl-LDHs/AC shows good uptake for aqueous sulfur dioxide (483.09mg/g) and hydrogen sulfide (181.15mg/g), respectively at 25°C. Meanwhile, the electrochemical removals of aqueous sulfur dioxide and hydrogen sulfide were respectively investigated at the mix of CeO2-NiAl-LDHs/AC and carbon nano-tubes modified homed paraffin-impregnated electrode. Both sulfur dioxide and hydrogen sulfide could be effectively oxidized to sulfuric acid at 1.0V in alkaline aqueous solution. © 2015 Elsevier B.V.

  13. Synthesis and characterization of bimetallic Pd-Ni catalysts in a CeO2 matrix for the generation of H2 by the reforming reaction of methanol

    International Nuclear Information System (INIS)

    Contreras C, R.

    2016-01-01

    The hydrothermal method was used for the synthesis of CeO 2 nano rods using Ce(NO 3 ) 3 ·6H 2 O and NH 4 OH. The catalytic support was calcined at 700 degrees Celsius. The synthesis of CeO 2 nano rods were impregnated with an aqueous solution of Ni(NO 3 ) 2 ·6H 2 O by an incipient wetness impregnation method at an appropriate concentration to yield 5 and 15% of Ni in the catalysts. Then 0.5% of Pd was impregnated using PdCl 2 . The samples obtained were calcined at 400 and reduced at 450 degrees Celsius. The catalytic materials were characterized by: temperature programmed reduction (TPR), Scanning Electron Microscopy (Sem) , surface area and X-ray diffraction (XRD) . Sem results showed that the CeO 2 is formed by nano rods and in lesser proportion semi spherical particles. Bet surface area of the catalysts decreases with Ni loading onto the CeO 2 nano rods. Pd O and Ni O were reduced at low and high temperature as was observed by TPR. The CeO 2 one-dimensional nano rods showed a highly crystalline structure with sharp diffraction peaks, with a typical fluorite structure (cubic structure of the CeO 2 ) and characteristic peaks corresponding to metallic Ni. No diffraction peaks of Pd were found. This is due to the low concentration of this metal in the catalyst. These catalysts showed high activity and selectivity to H 2 at maximum reaction temperature. According to the results of activity and selectivity, the catalysts with Pd-Ni are an alternative for the H 2 production in auto thermal reforming reaction of methanol. (Author)

  14. Construction of g-C3N4/CeO2/ZnO ternary photocatalysts with enhanced photocatalytic performance

    Science.gov (United States)

    Yuan, Yuan; Huang, Gui-Fang; Hu, Wang-Yu; Xiong, Dan-Ni; Zhou, Bing-Xin; Chang, Shengli; Huang, Wei-Qing

    2017-07-01

    Promoting the spatial separation of photoexcited charge carriers is of paramount significance for photocatalysis. In this work, binary g-C3N4/CeO2 nanosheets are first prepared by pyrolysis and subsequent exfoliation method, then decorated with ZnO nanoparticles to construct g-C3N4/CeO2/ZnO ternary nanocomposites with multi-heterointerfaces. Notably, the type-II staggered band alignments existing between any two of the constituents, as well as the efficient three-level transfer of electron-holes in unique g-C3N4/CeO2/ZnO ternary composites, leads to the robust separation of photoexcited charge carriers, as verified by its photocurrent increased by 8 times under visible light irradiation. The resulting g-C3N4/CeO2/ZnO ternary nanocomposites unveil appreciably increased photocatalytic activity, faster than that of pure g-C3N4, ZnO and g-C3N4/CeO2 by a factor of 11, 4.6 and 3.7, respectively, and good stability toward methylene blue (MB) degradation. The remarkably enhanced photocatalytic activity of g-C3N4/CeO2/ZnO ternary heterostructures can be interpreted in terms of lots of active sites of nanosheet shapes and the efficient charge separation owing to the resulting type-II band alignment with more than one heterointerface and the efficient three-level electron-hole transfer. A plausible mechanism is also elucidated via active species trapping experiments with various scavengers, which indicating that the photogenerated holes and •OH radicals play a crucial role in photodegradation reaction under visible light irradiation. This work suggest that the rational design and construction of type II multi-heterostructures is powerful for developing highly efficient and reusable visible-light photocatalysts for environmental purification and energy conversion.

  15. Investigation of the physical, optical, and photocatalytic properties of CeO2/Fe-doped InVO4 composite

    Science.gov (United States)

    Chaison, Jindaporn; Wetchakun, Khatcharin; Wetchakun, Natda

    2017-12-01

    The CeO2/Fe-doped InVO4 composites with various Fe concentrations (0.5, 1.0, 2.0, 5.0 and 6.0 mol%) was synthesized by homogeneous precipitation and hydrothermal methods. The as-synthesized samples were characterized by powder X-ray diffraction (XRD), Brunauer Emmett and Teller (BET)-specific surface area, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and UV-visible diffuse reflectance spectroscopy (DRS). Fe-doping into InVO4 crystal induces the distortion of the crystalline structure, the transformation of InVO4 morphology, and the new energy subband level generation of Fe between the CB and VB edge of InVO4. The electron excitation from the VB to Fe orbitals results in the decreased band gap and the extended absorption of visible-light, and thus enhances its photocatalytic performance. Visible-light-driven photocatalytic degradation of Rhodamine B (RhB) dye in water was used to evaluate the photocatalytic performance of CeO2/Fe-doped InVO4 composites. The results revealed that there is an optimum Fe (5.0 mol %) doping level. The composite with the optimum doping level obtains high photocatalytic activity of CeO2/Fe-doped InVO4 composite compared to pure CeO2 and pure InVO4 host. The increase of photocatalytic activity of CeO2/Fe-doped InVO4 composite was ascribed to the surface area, crystal defect, and band gap energy. Moreover, the photocatalytic enhancement is also because iron ions act as a trapping site, which results in the higher separation efficiency of photogenerated electrons and holes pairs in the CeO2/InVO4 composite. The evaluation of radical scavengers confirmed that hydroxyl radical was the main active species during the photodegradation of RhB. These synergistic effects are responsible for the enhanced photocatalytic activity of CeO2/Fe-doped InVO4 composite. Furthermore, the possible enhanced photocatalytic mechanism

  16. Yönetim Değişikliği ve Finansal Rapor Manipülasyonları = Ceo Turnover and Financial Report Manipulations

    Directory of Open Access Journals (Sweden)

    Selim AREN

    2009-01-01

    Full Text Available This paper interrogates if a manipulation exists in the financial statements of ISE (Istanbul Stock Exchange traded companies due to the changes of their CEOs in the period of 1998-2003. Analysis of variance has been conducted to clarify if the study variables have significant mean differences among those companies that changed their CEOs and those that did not. As a result, it is found that some types of manipulation might happen related to some study variables ; and beside others, the mostly preferred variables are general managerial costs and long term debts.

  17. Incineration of a Commercial Coating with Nano CeO2

    Science.gov (United States)

    Le Bihan, Olivier; Ounoughene, Ghania; Meunier, Laurent; Debray, Bruno; Aguerre-Chariol, Olivier

    2017-06-01

    The potential environmental risk arising from the incineration of waste containing nanomaterials is a new field which deserves further attention. Some recent studies have begun to focus on this topic but the data are incomplete. In addition, there is a need to consider real life waste. The present study gives some insight into the fate and behavior of a commercial coating containing a commercial additive (7% w/w) based on nano-CeO2 (aggregates of 10 to 40 nm, with elemental particles of 2-3 nm). The tests have been conducted with a system developed in the frame of the NanoFlueGas project. The test protocol was designed to respect the regulatory criteria of a good combustion in incineration plants (temperature around 850°C, highly ventilated combustion, at least 2 s residence time for the combustion gas in a post-combustion chamber at 850°C, and high oxygen/fuel contact). Time tracking by electric low pressure impaction (ELPI) shows that the incineration produces aerosol with number concentration dominated by sub-100 nm particles. Cerium is observed by TEM and EDS analysis but as a minor compound of a sub-group of particles. No nanoCeO2 particles have been observed in the aerosol. ICP-MS analysis indicates that the residual material consists mainly of CeO2 (60% of the mass). Observation by TEM establishes that this material is in the form of aggregates with individual particle of 40-200 nm and suggests that sintering occurred during incineration. As a conclusion, the lab scale incineration study led mainly to the release of nano-CeO2 in the residual material, as the major component. Its size distribution is different than the one of the nano-CeO2 observed in the initial sample before incineration. Additional research is needed to improve the understanding of nanoCeO2 behavior, and to integrate experiments at lab and real scale.

  18. Fabrication of CeO2nanoparticles decorated three-dimensional flower-like BiOI composites to build p-n heterojunction with highly enhanced visible-light photocatalytic performance.

    Science.gov (United States)

    Song, Hongbo; Wu, Ruiyang; Yang, Junfeng; Dong, Jianchao; Ji, Guijuan

    2018-02-15

    Three-dimensional (3D) flower-like CeO 2 /BiOI heterostructures with different Ce/Bi molar ratio were successfully synthesized via a hydrothermal method using polyvinylpyrrolidone (PVP) as surfactant. The X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) results indicate that the CeO 2 nanoparticles were successfully loaded on the surface of the flower-like BiOI. The photodegradation experiment demonstrated that the photocatalytic efficiency of CeO 2 /BiOI samples were higher than that of pure BiOI and CeO 2 , and CeO 2 /BiOI heterostructure showed the best photocatalytic performance when the amount of CeO 2 located at BiOI up to 15%. The result also exhibits that CeO 2 /BiOI catalysts possess higher photocatalytic efficiency for Rhodamine B (RhB) and methylene orange (MO) degradation, while it has a slight influence for phenol elimination. Meanwhile, the repeated photocatalytic degradation of RhB experiment reveals excellent photostability. A possible mechanism of photocatalysis was also explored and proposed. Furthermore, loading CeO 2 on the surface of BiOI can accelerate the separation rate of photogenerated electron-hole pairs, which is analyzed by photoluminescence (PL) spectroscopy, photocurrent experiments (PC) and electrochemical impedance spectroscopy (EIS). These results exhibit that BiOI can be modified by CeO 2 and there exists synergistic effect between CeO 2 and BiOI. The present work provides a new means to synthesize heterostructured photocatalyst for environmental remediation. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Shape tailored green synthesis of CeO2:Ho3+ nanopowders, its structural, photoluminescence and gamma radiation sensing properties

    Science.gov (United States)

    Malleshappa, J.; Nagabhushana, H.; Kavyashree, D.; Prashantha, S. C.; Sharma, S. C.; Premkumar, H. B.; Shivakumara, C.

    2015-06-01

    CeO2:Ho3+ (1-9 mol%) nanopowders have been prepared by efficient and environmental friendly green combustion method using Aloe vera gel as fuel for the first time. The final products are well characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), fourier transform infrared (FTIR). Bell, urchin, core shell and flower like morphologies are observed with different concentrations of the A. vera gel. It is apparent that by adjusting the concentration of the gel, considerable changes in the formation of CeO2:Ho3+ nano structures can be achieved. Photoluminescence (PL) studies show green (543, 548 nm) and red (645, 732 nm) emissions upon excited at 400 nm wavelength. The emission peaks at ∼526, 548, 655 and 732 nm are associated with the transitions of 5F3 → 5I8, 5S2 → 5I8, 5F5 → 5I8 and 5S2 → 5I7, respectively. Three TL glow peaks are observed at 118, 267 and 204 °C for all the γ irradiated samples which specify the surface and deeper traps. Linear TL response in the range 0.1-2 kGy shows that phosphor is fairly useful as γ radiation dosimeter. Kinetic parameters associated with the glow peaks are estimated using Chen's half width method. The CIE coordinate values show that phosphor is quite useful for the possible applications in WLEDs as orange red phosphor.

  20. Extended parental care in crustaceans: an update Cuidado parental extendido en crustáceos: conocimiento actual

    Directory of Open Access Journals (Sweden)

    MARTIN THIEL

    2003-06-01

    increase in dispersal distances of crustaceans with XPC via rafting, surpassing that of crustaceans with pelagic larvae. Since crustaceans with XPC may be particularly susceptible to changing environmental conditions, especially in the terrestrial environment where populations are often small and locally restricted, conservation of biodiversity should focus on these (and other invertebrate species with XPCMuchas especies de crustáceos presentan cuidado parental extendido (XPC, donde individuos juveniles completamente desarrollados son cuidados por los padres. En la presente contribución se revisa el conocimiento actual del XPC, sus consecuencias y además se identifican tópicos importantes para ser investigados en el futuro. Los crustáceos que presentan XPC pueden ser encontrados en ambientes marinos, límnicos y terrestres, pero el XPC es más conspicuo y aparentemente más común en el ambiente terrestre. En todas las especies analizadas, las hembras desarrollan las principales tareas relacionadas con el XPC. Crustáceos que portan sus juveniles en alguna estructura del cuerpo (i.e. marsupio durante el XPC liberan a estos tempranamente, mientras que las especies que habitan refugios pueden albergar a sus crías incluso cuando éstas alcanzan estadios tardíos de desarrollo, o bien, la adultez. Además de proveer un microhabitat adecuado y seguro para las crías, las madres comparten el alimento con, limpian y/o defienden activamente a sus juveniles. Entre los beneficios más importantes del XPC figura el incremento de las tasas de crecimiento y sobrevivencia de los juveniles. El XPC puede producir conflictos entre las crías o entre los padres y sus crías, especialmente durante la etapa tardía del XPC, cuando algunos recursos (alimento y espacio pueden llegar a ser aún más limitantes. De manera similar, debido a la proximidad y frecuente interacción entre padres y crías, epibiontes (e.g., parásitos pueden ser transferidos desde los padres hacia los juveniles

  1. Laser clad Ni-base alloy added nano- and micron-size CeO 2 composites

    Science.gov (United States)

    Zhang, Shi Hong; Li, Ming Xi; Cho, Tong Yul; Yoon, Jae Hong; Lee, Chan Gyu; He, Yi Zhu

    2008-07-01

    Micron-size Ni-base alloy (NBA) powders are mixed with both 1.5 wt% (%) micron-CeO 2 (m-CeO 2) and also 1.0-3.0% nano-CeO 2 (n-CeO 2) powders. These mixtures are coated on low carbon steel (Q235) by 2.0 kW CO 2 laser cladding. The effects on microstructures, microhardness and wear resistance of the coating by the addition of m- and n-CeO 2 powders to NBA (m- and n-CeO 2/NBA) have been investigated. Addition to the primary phases of γ-Ni, Cr 23C 6 and Ni 3B of NBA coating, CeNi 3 shows up both in m- and n-CeO 2/NBA coatings and CeNi 5 appears only in n-CeO 2/NBA coating. Directional dendrite and coarse equiaxed dendrite are grown in m-CeO 2/NBA coating from interface to central zone, whereas multi-oriented dendrite and fine equiaxed dendrite growth by addition of n-CeO 2. The microhardness and wear resistance of coatings are greatly improved by CeO 2 powder addition, and compared to the addition of 1.0% and 3.0%, 1.5% n-CeO 2/NBA is the best. Hardness and wear resistance of the coating improves with decreasing CeO 2 size from micron to nano.

  2. Hybrid nanocomposite from aniline and CeO2 nanoparticles: Surface protective performance on mild steel in acidic environment

    Science.gov (United States)

    Sasikumar, Y.; Kumar, A. Madhan; Gasem, Zuhair M.; Ebenso, Eno E.

    2015-03-01

    This present work contributes to the development of a new generation of active corrosion inhibitors composed of CeO2 nanoparticles covered with polyaniline that are able to release entrapped nanoparticles in acidic medium. Nanocomposites of aniline and CeO2 nanoparticles have been chemically synthesized by in-situ polymerization. The structural evolutions and morphological characteristics of PANI/CeO2 nanocomposite (PCN) have performed using various techniques such as XRD, IR, XPS, SEM and TEM analysis. It was illustrated from SEM and TEM observation that the PCN has globular particle with core-shell structure. The inhibition properties of synthesized PCN on mild steel (MS) corrosion in 0.5 M HCl were estimated using weight loss and electrochemical techniques. Potentiodynamic polarization results revealed PCN to be a mixed-type inhibitor, while impedance results indicate the adsorption of the PCN film on the MS surface. The inhibition efficiency of PCN was found to increase almost linearly with concentration. Moreover, an increase in the water contact-angle with PCN indicated its adsorption at the MS surface, and ATR-IR, SEM/EDAX and AFM visualization confirmed the formation of a protective film adsorbed on a MS surface. Finally, it was concluded that the PCN is a potential inhibitor for mild steel in HCl medium.

  3. ceosé řízení pohonů v inteligentní budově

    OpenAIRE

    Uherka, Bohumil

    2010-01-01

    Bakalářská práce se zabývá problematikou víceosého řízení pohonů pomocí elektronické vačky a elektronické převodovky. Výsledkem práce bylo vytvoření modelu vstupních vrat a programu víceosého řízení pohonů. Tato problematika byla demonstrována na motorech ovládajících vstupní vrata u inteligentního domu. S použitím krokových motorů byl vytvořen model vstupních vrat, který byl propojen pomocí vstupních a výstupních modulů s Power Panelem (programovatelný automat s dotykovým displejem), na němž...

  4. Some Pros and Cons of Laptop Use in Class

    Science.gov (United States)

    Harris, R. W.

    2018-05-01

    We did not have laptops or computer networks in schools in 1968, when I started teaching physics. When classroom computers became available, followed by the internet, I greeted them as great educational tools. I developed my own website in order to provide reference material and assignments for my students. I found that online assignments were more likely than traditional ones to be completed. I also had my own system making password-protected grades available online. The parents loved it. I began giving some tests online. However, there is a downside to laptop use in class.

  5. Preparation and characterization of p–n heterojunction CuBi2O4/CeO2 and its photocatalytic activities under UVA light irradiation

    Directory of Open Access Journals (Sweden)

    Abdelkader Elaziouti

    2015-04-01

    Full Text Available CuBi2O4/CeO2 nanocomposites were synthesized by the solid state method and were characterized by a number of techniques such as X-ray diffraction, scanning electron microscopy and UV–Vis diffuse reflectance spectroscopy. The photocatalytic activity of the samples was investigated under UVA light and assessed using Congo red (CR dye as probe reaction. The efficiency of the coupled CuBi2O4/CeO2 photocatalyst was found to be related to the amount of added CuBi2O4 and to the pH medium. The CuBi2O4/CeO2 photocatalyst exhibited the high efficiency as a result of 83.05% of degradation of CR under UVA light for 100 min of irradiation time with 30 wt% of CuBi2O4 at 25 °C and pH 7, which is about 6 times higher than that of CeO2. The photodegradation reactions satisfactorily correlated with the pseudo-first-order kinetic model. The mechanism of the enhanced photocatalytic efficiency was explained by the heterojunction model.

  6. Corrosion of alloy 800H and the effect of surface-applied CeO2 in a sulphidizing/oxidizing/carburizing environment at 700°C

    NARCIS (Netherlands)

    Stroosnijder, M.F.; Guttmann, V.; Fransen, T.; de Wit, J.H.W.

    The corrosion behavior of a wrought austenitic Fe-20Cr-32Ni steel, Alloy 800H, was studied in a simulated coal-gasification atmosphere at 700°C for exposure times up to 2500 hr. The influence of preoxidation and CeO2-surface application followed by preoxidation on the corrosion resistance of this

  7. Dissolved cerium contributes to uptake of Ce in the presence of differently sized CeO2-nanoparticles by three crop plants.

    Science.gov (United States)

    Schwabe, Franziska; Tanner, Simon; Schulin, Rainer; Rotzetter, Aline; Stark, Wendelin; von Quadt, Albrecht; Nowack, Bernd

    2015-03-01

    We investigated the uptake of cerium (Ce) dioxide nanoparticles (NPs) by hydroponically grown wheat, pumpkin and sunflower plants. The presence of plant roots in nutrient solution led to a substantial increase in the dissolution of CeO2-NP compared to plant-free medium. Experiments with Zr/CeOx-NP revealed that Ce was not only taken up in the form of NPs, but simultaneously to a significant degree also as dissolved Ce(iii) ions, which then re-precipitated in the form of CeO2-NPs inside the leaves. The contribution of dissolved Ce uptake was particularly large for particles smaller than 10 nm due to their higher dissolution rate. Our data also indicate that the translocation of Ce resulting from NP-root-exposure is species dependent. When Ce was supplied as dissolved ions, sunflower had the highest capacity of Ce-ion accumulation inside the leaves, while there was no significant difference between pumpkin and wheat. We found no Ce translocation from roots into shoots when only NPs bigger than 20 nm were applied. This study highlights that plant root activity can have a significant impact on the dissolution of CeO2-NPs in soil solution and that uptake of dissolved Ce(iii) followed by re-precipitation needs to be considered as an important pathway in studies of CeO2-NP uptake by plants.

  8. Facile Synthesis of CeO2-LaFeO3 Perovskite Composite and Its Application for 4-(Methylnitrosamino-1-(3-Pyridyl-1-Butanone (NNK Degradation

    Directory of Open Access Journals (Sweden)

    Kaixuan Wang

    2016-04-01

    Full Text Available A facile and environmentally friendly surface-ion adsorption method using CeCO3OH@C as template was demonstrated to synthesize CeO2-LaFeO3 perovskite composite material. The obtained composite was characterized by X-ray diffraction (XRD, fourier transform infrared spectra (FT-IR, field-emission scanning electron microscopy (FE-SEM, transmission electron microscopy (TEM, thermo-gravimetric analysis and differential scanning calorimetry (TG-DSC, N2 adsorption/desorption isotherms and X-ray photoelectron spectra (XPS measurements. The catalytic degradation of nitrosamine 4-(methylnitrosamino-1-(3-pyridyl-1-butanone (NNK was tested to evaluate catalytic activity of the CeO2-LaFeO3 composite. Much better activity was observed for the CeO2-LaFeO3 composite comparing with CeO2 and LaFeO3. These results suggested that perovskite composite materials are a promising candidate for the degradation of tobacco-specific nitrosamines (TSNAs.

  9. It's an inside job. Tenet moves Fetter to CEO: now he has to convince critics it doesn't take an outsider to solve the company's problems.

    Science.gov (United States)

    Galloro, Vince

    2003-09-22

    Tenet Healthcare Corp. has made it official-naming Trevor Fetter, left, the company's chief executive officer. He had served as acting CEO since Jeffrey Barbakow resigned last spring. Fetter had a lot going for him in the race for the post--he worked at Tenet and its spinoff Broadlane since 1995, but he faces many challenges at the troubled company.

  10. Metabolomic effects of CeO2, SiO2 and CuO metal oxide nanomaterials on HepG2 cells

    Data.gov (United States)

    U.S. Environmental Protection Agency — The data set is a matrix of cellular biochemical (metabolites) in HepG2 cells treated with various metal oxide nanomaterials composed of CeO2, SiO2 and CuO. This...

  11. Influence of argon and oxygen pressure ratio on bipolar-resistive switching characteristics of CeO2- x thin films deposited at room temperature

    Science.gov (United States)

    Ismail, Muhammad; Ullah, Rehmat; Hussain, Riaz; Talib, Ijaz; Rana, Anwar Manzoor; Hussain, Muhammad; Mahmood, Khalid; Hussain, Fayyaz; Ahmed, Ejaz; Bao, Dinghua

    2018-02-01

    Cerium oxide (CeO2-x) film was deposited on Pt/Ti/SiO2/Si substrate by rf magnetron sputtering at room temperature. Resistive switching characteristics of these ceria films have been improved by increasing oxygen content during deposition process. Endurance and statistical analyses indicate that the operating stability of CeO2-x-based memory is highly dependent on the oxygen content. Results indicate that CeO2-x film-based RRAM devices exhibit optimum performance when fabricated at an argon/oxygen ratio of 6:24. An increase in the oxygen content introduced during CeO2-x film deposition not only stabilizes the conventional bipolar RS but also improves excellent switching uniformity such as large ON/OFF ratio (102), excellent switching device-to-device uniformity and good sweep endurance over 500 repeated RS cycles. Conduction in the low-resistance state (LRS) as well as in the low bias field region in the high-resistance state (HRS) is found to be Ohmic and thus supports the conductive filament (CF) theory. In the high voltage region of HRS, space charge limited conduction (SCLC) and Schottky emission are found to be the dominant conduction mechanisms. A feasible filamentary RS mechanism based on the movement of oxygen ions/vacancies under the bias voltage has been discussed.

  12. Separation of carrier-free gadolinium produced in an 80 MeV 12C6+ irradiated CeO2 target

    International Nuclear Information System (INIS)

    Nayak, Dalia; Lahiri, Susanta; Das, N.R.; Das, S.K.; Ramaswami, A.; Manohor, S.B.

    1999-01-01

    Charged particle activation of natural CeO 2 with 80 MeV 12 C +6 results in the formation of the carrier-free gadolinium isotopes, 147,149 Gd, in the matrix. The liquid cation exchanger, HDEHP, has been utilized effectively as an extractant in the quantitative separation of these gadolinium isotopes from the bulk target matrix of ceric oxide

  13. Efficient degradation of chlorobenzene in a non-thermal plasma catalytic reactor supported on CeO2/HZSM-5 catalysts.

    Science.gov (United States)

    Jiang, Liying; Nie, Guofeng; Zhu, Runye; Wang, Jiade; Chen, Jianmeng; Mao, Yubo; Cheng, Zhuowei; Anderson, Willam A

    2017-05-01

    Chlorobenzene removal was investigated in a non-thermal plasma reactor using CeO 2 /HZSM-5 catalysts. The performance of catalysts was evaluated in terms of removal and energy efficiency. The decomposition products of chlorobenzene were analyzed. The results show that CeO 2 /HZSM-5 exhibited a good catalytic activity, which resulted in enhancements of chlorobenzene removal, energy efficiency, and the formation of lower amounts of by-products. With regards to CO 2 selectivity, the presence of catalysts favors the oxidation of by-products, leading to a higher CO 2 selectivity. With respect to ozone, which is considered as an unavoidable by-product in air plasma reactors, a noticeable decrease in its concentration was observed in the presence of catalysts. Furthermore, the stability of the catalyst was investigated by analyzing the evolution of conversion in time. The experiment results indicated that CeO 2 /HZSM-5 catalysts have excellent stability: chlorobenzene conversion only decreased from 78% to 60% after 75hr, which means that the CeO 2 /HZSM-5 suffered a slight deactivation. Some organic compounds and chlorinated intermediates were adsorbed or deposited on the catalysts surface as shown by the results of Fourier Transform Infrared (FT-IR) spectroscopy, scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses of the catalyst before and after the reaction, revealing the cause of catalyst deactivation. Copyright © 2016. Published by Elsevier B.V.

  14. Metabolomic effects of CeO2, SiO2 and CuO metal oxide nanomaterials on HepG2 cells

    Science.gov (United States)

    Abstract Background To better assess potential hepatotoxicity of nanomaterials, human liver HepG2 cells were exposed for 3 days to five different CeO2 (either 30 or 100 μg/ml), 3 SiO2 based (30 μg/ml) or 1 CuO (3 μg/ml) nanomaterials with dry primary particle sizes r...

  15. Strongly coupled CeO2/Co3O4/poly(3,4-ethylenedioxythiophene) nanofibers with enhanced nanozyme activity for highly sensitive colorimetric detection

    Science.gov (United States)

    Chi, Maoqiang; Zhu, Yun; Yang, Zezhou; Gao, Mu; Chen, Sihui; Song, Na; Wang, Ce; Lu, Xiaofeng

    2017-07-01

    In this work, we have prepared CeO2/Co3O4 composite nanofibers via an electrospinning technique followed by a calcination process. Then core-shell structured CeO2/Co3O4/poly(3,4-ethylenedioxythiophene) (PEDOT) composite nanofibers were fabricated through a redox reaction between the 3,4-ethylenedioxythiophene (EDOT) monomer and Co3O4 on the surface of CeO2/Co3O4 composite nanofibers. The morphology and composition of the two composite nanofibers were confirmed by field-emission scanning electron microscopy, transmission electron microscopy, x-ray diffraction, Fourier transform infrared spectroscopy, and x-ray photoelectron spectra measurements. Due to the synergistic effect between CeO2 and Co3O4, the catalytic activity was enhanced compared to that of independent oxide nanofibers. After the growth of PEDOT, the catalytic activity process was further improved, having achieved a secondary synergistic effect. Application of the two prepared composite nanofibers as peroxidase-like catalysts for the colorimetric detection of H2O2 was investigated. It is anticipated that this work can inspire researchers to develop various novel functional nanocomposites for applications in biosensing and environmental monitoring.

  16. Water-based synthesis of TiO2/CeO2 composites supported on plasma-treated montmorillonite for parathion methyl degradation

    Czech Academy of Sciences Publication Activity Database

    Henych, Jiří; Kormunda, M.; Šťastný, Martin; Janoš, P.; Vomáčka, Petr; Matoušek, J.; Štengl, Václav

    2017-01-01

    Roč. 144, AUG (2017), s. 26-35 ISSN 0169-1317 R&D Projects: GA MŠk(CZ) LM2015073 Institutional support: RVO:61388980 Keywords : Montmorillonite * Parathion methyl * Plasma treatment * TiO2 /CeO2 composites Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 3.101, year: 2016

  17. Study of the defect structure of ''pure'' and doped nonstoichiometric CeO2. Final report, January 1, 1965--May 31, 1977

    International Nuclear Information System (INIS)

    Blumenthal, R.N.

    1977-11-01

    The defect structure and transport properties of defects in nonstoichiometric oxides was studied based on their electrical and thermodynamic behavior. Similar studies were also made on doped-nonstoichiometric oxides to determine the effect of the ionic radii, valence and concentration of the dopant cation on the nonstoichiometric defect structure and the transport properties of these defects. The thermodynamic and electrical property study on ''pure'' and doped-nonstoichiometric CeO 2 /sub -x/ is reviewed. The combined study of the electrical conductivity, ionic transference, and thermodynamic measurements initiated on CaO-doped CeO 2 as a function of temperature, oxygen pressure and CaO content is discussed. The results of similar measurements on CeO 2 doped with other oxides (e.g., ThO 2 , Ta 2 O 5 , etc.) which have cations with different valences and ionic radii are also discussed. The primary objective of these studies was to determine the effect of ionic radii, valence and concentration of the dopant cation on (1) the nonstoichiometric behavior, (2) the thermodynamic quantities ΔantiH/sub O 2 / and ΔantiS/sub O 2 /, (3) the nonstoichiometric defect structure, (4) the electronic and ionic conductivities, and (5) the mobility of electrons and oxygen vacancies in doped CeO 2 /sub -x/

  18. Comment on 'The characterization of doped CeO2 electrodes in solid oxide fuel cells' by B.G. Pound

    DEFF Research Database (Denmark)

    Ranløv, J.; Poulsen, F.W.; Mogensen, Mogens Bjerg

    1993-01-01

    Electrode tests and ac impedance measurements presented by Pound on Ni, Co and Mn doped CeO2 are reviewed. We find that the stability of solid solutions in the systems of NiO-CeO2 and CoO-CeO2 are improbable and that therefore the interpretation of ac impedance data and electrode tests should...

  19. Building the "fable hospital"--the CEO's perspective: an interview with Michael H. Covert, president and chief executive officer, Palomar Pomerado Health. Interview by David A Tam.

    Science.gov (United States)

    Covert, Michael

    2012-01-01

    Hospital construction is a significant event in any health system. The financial implications are great, especially at a time of shrinking capital resources. Personnel are affected, as are the processes to perform their tasks. Often, new facilities are catalysts that change organizational culture; it has been clearly shown that new facilities have a positive impact on patient satisfaction scores. The members of the C-suite of a hospital/health system play important roles in construction projects. However, no one is more critical to the success of such major endeavors than the chief executive officer (CEO). The CEO sets the tone for the project, giving direction to the design and construction process that may have implications for the rest of the organization. Palomar Pomerado Health (PPH) is the largest public health district in California. In 2002, the PPH governing board authorized the creation of a new facility master plan for the district, which included the construction of a replacement facility for its tertiary care trauma center. The new Palomar Medical Center is slated to open in August 2012. HERD had the opportunity to speak with PPH CEO Michael H. Covert on the role of the CEO in the building of this "fable hospital".

  20. Germination and early plant development of 10 plant species exposed to Nano TiO2 and CeO2

    Science.gov (United States)

    Ten agronomic plant species were exposed to different concentrations of nano-TiO2 or CeO2 (0, 250, 500 and 1000 ug/l) and followed to examine effects on germination and early seedling development. For TiO2, cabbage showed increased and corn decreased percent germination, while ...

  1. Dose-Dependent Effects of CeO2 on Microstructure and Antibacterial Property of Plasma-Sprayed TiO2 Coatings for Orthopedic Application

    Science.gov (United States)

    Zhao, Xiaobing; Liu, Gaopeng; Zheng, Hai; Cao, Huiliang; Liu, Xuanyong

    2015-02-01

    Titanium and its alloys have been used extensively for orthopedic and dental implants. Although these devices have achieved high rates of success, two major complications may be encountered: the lack of osseointegration and the biomaterial-related infection. Accordingly, cerium oxide (CeO2)-doped titanium oxide (TiO2) materials were coated on titanium by an atmospheric plasma spraying (APS) technique. The phase structures, morphologies, and surface chemical states of the obtained coatings were characterized by x-ray diffraction, scanning electron microscopy, and x-ray photoelectron spectroscopy techniques. The in vitro antibacterial and cytocompatibility of the materials were studied with Staphylococcus aureus ( S. aureus, ATCC25923) and osteoblast precursor cell line MC3T3-E1. The results indicated that the addition of CeO2 shifts slightly the diffraction peaks of TiO2 matrix to low angles but does not change its rutile phase structure. In addition, the CeO2/TiO2 composite coatings possess dose-dependent corrosion resistance and antimicrobial properties. And doping of 10 wt.% CeO2 exhibits the highest activity against S. aureus, improved corrosion resistance, and competitive cytocompatibility, which argues a promising option for balancing the osteogenetic and antibacterial properties of titanium implants.

  2. Controlled synthesis of CeO2 microstructures from 1D rod-like to 3D lotus-like and their morphology-dependent properties

    Science.gov (United States)

    Gong, Jinfeng; Meng, Fanming; Fan, Zhenghua; Li, Huijie

    2016-10-01

    Monodisperse 3D lotus-like CeO2 microstructures have been successfully synthesized via controlling the morphology of CeCO3OH precursors under hydrothermal condition as well as subsequent calcination. The reaction time was systematically investigated. XRD, FT-IR, SEM, TEM, XPS, Raman scattering and Photoluminescence (PL) spectra were employed to characterize the samples. The lotus-like CeO2 hierarchical structures with an average of 4-6 μm are composed of many nanoplates of 100-200 nm in thickness as the petals stacking together to form open flowers and have a fluorite cubic structure. Based on the time-dependent morphology evolution evidences, a nucleation-dissolution-recrystallization mechanism has been proposed to explain the transformation from rod-like structures to lotus-like CeO2 hierarchical structures with the increase of reaction time. It is found that there are Ce3+ ions and oxygen vacancies in surface of samples. The magnetic and photoluminescence measurements indicated that all CeO2 samples exhibit excellent ferromagnetism and optical properties at room temperature, and while increasing the reaction time, the ferromagnetism and optical properties increase more, which can be reasonably explained for the influences of the different morphology of the particles and the concentration of oxygen vacancies and Ce3+ ions. [Figure not available: see fulltext.

  3. The Classification for Early-onset Scoliosis (C-EOS) Correlates With the Speed of Vertical Expandable Prosthetic Titanium Rib (VEPTR) Proximal Anchor Failure

    Science.gov (United States)

    Park, Howard Y.; Matsumoto, Hiroko; Feinberg, Nicholas; Roye, David P.; Kanj, Wajdi W.; Betz, Randal R.; Cahill, Patrick J.; Glotzbecker, Michael P.; Luhmann, Scott J.; Garg, Sumeet; Sawyer, Jeffrey R.; Smith, John T.; Flynn, John M.; Vitale, Michael G.

    2017-01-01

    Background The Classification for Early-onset Scoliosis (C-EOS) was developed by a consortium of early-onset scoliosis (EOS) surgeons. This study aims to examine if the C-EOS classification correlates with the speed (failure/unit time) of proximal anchor failure in EOS surgery patients. Methods A total of 106 EOS patients were retrospectively queried from an EOS database. All patients were treated with vertical expandable prosthetic titanium rib and experienced proximal anchor failure. Patients were classified by the C-EOS, which includes a term for etiology [C: Congenital (54.2%), M: Neuromuscular (32.3%), S: Syndromic (8.3%), I: Idiopathic (5.2%)], major curve angle [1: ≤20 degrees (0%), 2: 21 to 50 degrees (15.6%), 3: 51 to 90 degrees (66.7%), 4: >90 degrees (17.7%)], and kyphosis [“−”: ≤20 (13.5%), “N”: 21 to 50 (42.7%), “+”: >50 (43.8%)]. Outcome was measured by time and number of lengthenings to failure. Results Analyzing C-EOS classes with >3 subjects, survival analysis demonstrates that the C-EOS discriminates low, medium, and high speed of failure. The low speed of failure group consisted of congenital/51-90/hypokyphosis (C3−) class. The medium-speed group consisted of congenital/51-90/normal and hyperkyphosis (C3N, C3+), and neuromuscular/51-90/hyperkyphosis (M3+) classes. The high-speed group consisted of neuromuscular/51-90/normal kyphosis (M3N), and neuromuscular/>90/normal and hyperkyphosis (M4N, M4+) classes. Significant differences were found in time (P 90 degrees demonstrated significantly faster speed of failure compared with patients with major curve angle 21 to 50 degrees (P = 0.011). Conclusions The ability of the C-EOS to discriminate the speeds of failure of the various classification subgroups supports its validity and demonstrates its potential use in guiding decision making. Further experience with the C-EOS may allow more tailored treatment, and perhaps better outcomes of patients with EOS. Level of Evidence Level III

  4. Cetáceos del Pacífico de Guatemala: Cincuenta años de historia Guatemala's Pacific Cetaceans: Fifty Years of History

    Directory of Open Access Journals (Sweden)

    Andrea A. Cabrera Arreola

    2014-10-01

    Full Text Available En Guatemala el estudio de los cetáceos inició en la década de los sesenta con los primeros registros de varamiento y captura incidental. Sin embargo, pocos trabajos científicos con datos de cetáceos han sido publicados. Con el objetivo de centralizar la información de cetáceos y obtener conocimiento biológico para el desarrollo de planes de manejo y conservación, se realizó una revisión bibliográfica de cetáceos en Guatemala que recaba información de los últimos 50 años. Se obtuvo un total de 1,014 registros de avistamiento (1979-2011, 62 registros de captura incidental (1961/85 y 16 registros de varamientos (1975, 2007-2012, los cuales se analizaron en mapas batimétricos y en mapas de presiones antropogénicas. Se identificaron diecinueve especies pertenecientes a cinco familias de cetáceos, incluyendo Balaenopteridae, Delphinidae, Ziphiidae, Kogiidae y Physeteridae. El esfuerzo y área de muestreo varió durante 1961-2012. Se identificaron diferentes patrones de distribución especie-específicos. La mayoría de avistamientos se registraron cerca de zonas con topografía compleja. Aunque los eventos de captura incidental se registraron únicamente en alta mar, los resultados sugieren que especies de distribución costera se encuentran en zonas con mayor riesgo antropogénico. Se reportaron ocho especies de cetáceos varados, eventos ocurridos principalmente en el departamento de Escuintla desde el año 2007. Debido a la gran diversidad en los patrones de distribución, comportamiento y uso de hábitat de los cetáceos, combinado con los riesgos antropogénicos de la zona, es necesario que se considere un enfoque integral cuando se implementen planes de manejo y conservación marina en Guatemala.

  5. Colloidal stability of CeO2 nanoparticles coated with either natural organic matter or organic polymers under various hydrochemical conditions

    Science.gov (United States)

    Dippon, Urs; Pabst, Silke; Klitzke, Sondra

    2016-04-01

    The worldwide marked for engineered nanoparticles (ENPs) is growing and concerns on the environmental fate- and toxicity of ENPs are rising. Understanding the transport of ENPs within and between environmental compartments such as surface water and groundwater is crucial for exposition modeling, risk assessment and ultimately the protection of drinking water resources. The transport of ENPs is strongly influenced by the surface properties and aggregation behavior of the particles, which is strongly controlled by synthetic and natural organic coatings. Both, surface properties and aggregation characteristics are also key properties for the industrial application of ENPs, which leads to the development and commercialization of an increasing number of surface-functionalized ENPs. These include metals and oxides such as Cerium dioxide (CeO2) with various organic coatings. Therefore, we investigate CeO2 ENPs with different surface coatings such as weakly anionic polyvinyl alcohol (PVA) or strongly anionic poly acrylic acid (PAA) with respect to their colloidal stability in aqueous matrix under various hydrochemical conditions (pH, ionic strength) and their transport behavior in sand filter columns. Furthermore, we investigate the interaction of naturally occurring organic matter (NOM) with CeO2 ENPs and its effect on surface charge (zeta potential), colloidal stability and transport. While uncoated CeO2 ENPs aggregate at pH > 4 in aqueous matrix, our results show that PAA and PVA surface coatings as well as NOM sorbed to CeO2-NP surfaces can stabilize CeO2 ENPs under neutral and alkaline pH conditions in 1 mM KCl solution. Under slightly acidic conditions, differences between the three particle types were observed. PVA can stabilize particle suspensions in presence of 1 mM KCl at pH > 4.3, PAA at pH >4.0 and NOM at >3.2. While the presence of KCl did not influence particle size of NOM-CeO2 ENPs, CaCl2 at >2 mM lead to aggregation. Further results on the influence of KCl

  6. Estudos higiênicos sôbre os crustáceos e moluscos da Baía de Guanabara (Rio de Janeiro

    Directory of Open Access Journals (Sweden)

    Lejeune Pacheco Henriques de Oliveira

    1944-04-01

    Full Text Available Revisão da literatura médica sôbre higiene de crustáceos e moluscos marinhos. Intoxicações por elementos extranhos às carnes de crustáceos e moluscos: por sais de cobre, vegetais tóxicos; estranho e chumbo nas conservas de crustáceos; botulismo. Putrefação de ostras e doenças de ostras provocadas por cogumelos; crustáceos e moluscos guardados em geladeiras bolorentas. Lista das espécies de moluscos comestíveis da Bahia de Guanabara. Lista das espécies de crustáceos comestíveis da Bahia de Guanabara. Veiculação de micro-organismos patogênicos ao homem por intermédio das carnes de crustáceos e de moluscos: veiculação do vibrião colérico, dos bacilos tíficos e paratíficos e de germes do grupo coli e do gênero Proteus. Vitalidade dos bacilos tíficos nas ostras. Listas dos moluscos veiculadores dos agentes causadores das febres tíficas e paratíficas. Conceitos antigos e modernos sõbre intoxicações por crustáceos; partidas de crustáceos salubres ou não conforme o local de venda. Estudos experimentais sôbre a "talassina" princípio tóxico existente em alguns crustáceos. "Mitilotoxina", intoxicações por mexilhões e outros acidentes incriminados aos moluscos. Enterotoxina estavfilocócica em ostras. Métodos de determinação da salubridade dos moluscos; verificações nas ostras brasileiras. Depuração dos crustáceos pelas soluções cloradas. Estabulação de caranguejos denominados vulgarmente de "guaiamus" e "ussás".Recording main medical publication on Hygiene of Mollusca and Crustacea. Food-poisoning. Decomposing oysters, and shell-fish sickness by fungi. Catalogue of eatable Crustacea and Mollusca of Rio de Janeiro. Significance of Mollusca and Crustacea in the spread of diseases. Longevity of Vibrio comma, Eberthella typhosa, Salmonella schottmuelleri, Salmonella paratiphi. Escherichia coli in oysters, Microorganisms in marked oysters. Comparison old written papers with moderns publications on food

  7. Macroporous graphene capped Fe3O4for amplified electrochemiluminescence immunosensing of carcinoembryonic antigen detection based on CeO2@TiO2.

    Science.gov (United States)

    Yang, Lei; Zhu, Wenjuan; Ren, Xiang; Khan, Malik Saddam; Zhang, Yong; Du, Bin; Wei, Qin

    2017-05-15

    A novel electrochemiluminescence (ECL) signal-amplified immunosensing strategy was proposed by using gold nanoparticles (Au NPs) functionalized reduced graphene oxide (rGO) capped Fe 3 O 4 (Au-FrGO). In this work, CeO 2 @TiO 2 was prepared by a sol-gel method to wrap CeO 2 with TiO 2 . In the presence of CeO 2 , CeO 2 @TiO 2 exhibited better ECL activity than TiO 2 with peroxydisulfate as coreactant. In addition, FrGO with macroporous structure was synthesized by self-assembly of rGO sheets capped cationic Fe 3 O 4 nanoparticles, exhibiting larger specific surface area than rGO. Due to the low toxicity and magnetism of Fe 3 O 4 , FrGO owned more favorable biocompatibility and the application of magnetic-separation simplified the preparation procedure. After hybridizing with Au NPs, FrGO exhibited more excellent electrical conductivity and could immobilize more CeO 2 @TiO 2 and antibodies. Therefore, a novel label-free ECL immunosensor based on Au-FrGO-CeO 2 @TiO 2 was constructed which generated higher ECL response. To investigate the performance of the immunosensor, carcinoembryonic antigen (CEA) was chosen as a model target analyte. Under optimal conditions, the immunosensor had sensitive response to CEA in a wide linear range of 0.01pgmL -1 to 10ngmL -1 with a detection limit of 3.28 fg mL -1 . The proposed ECL immunosensor exhibited excellent stability, repeatability and selectivity, which opened another promising avenue for CEA determination in real serum samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Green chemical approach towards the synthesis of CeO2 doped with seashell and its bacterial applications intermediated with fruit extracts.

    Science.gov (United States)

    Arasu, Mariadas Valan; Thirumamagal, R; Srinivasan, M P; Al-Dhabi, Naif Abdullah; Ayeshamariam, A; Saravana Kumar, D; Punithavelan, N; Jayachandran, M

    2017-08-01

    Nanomaterials of CeO 2 with A. vera were synthesized by using simple chemical method. Grapes drops are used as an oxidizing agent. Structural and morphological studies of nanomaterials of cerium oxide (CeO 2 ), were studied for combustion method of preparation. The precursor solution was initialized by a hydrothermal reaction. Cerium hydroxyl carbonate precursors which involves cerium (III) nitrate Ce(NO 3 ) 3 . 6 H 2 O with (1.0M) of seashell powder, 3% A. vera, extracts, grapes and pomegranate drops and this complex solution was used to produce the CeO 2 powder particles. We have prepared another sample with 5% of Aloe vera extract and found that 3% Aloe vera extract has lesser grain size and enhanced band gap values, so the article explained the sample analysis of combination with 3% extract of Aloe vera. The product has the rod pattern which was the unusual features appear to originate from the unique crystal chemistry aspects. From the optical absorption spectrum, it has been shown that the CeO 2 rods have 3.847eV of direct band gap energy. The minimum inhibitory concentration (MIC) values of the synthesized compounds exhibited activity towards various microbial pathogens such as B. subtilis (15μg/mL), S. aureus (50μg/mL), S. epidermidis (20μg/mL), E. faecalis (25μg/mL) and towards E. coli (100μg/mL), K. pneumoniae (50μg/mL) and P. aeruginosa (75μg/mL) respectively. The tests on bacterial activities confirmed that the CeO 2 rods are suitable hand for the biological applications. The seashell structure and the phytochemical contents of A. vera might enhance its bacterial activities. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Estudo microestrutural do catalisador Ni/gama-Al2O3: efeito da adição de CeO2 na reforma do metano com dióxido de carbono Microstructural study of Ni/gamma-Al2O3 catalyst: addition effects of CeO2 on carbon dioxide reforming of methane

    Directory of Open Access Journals (Sweden)

    Antoninho Valentini

    2003-10-01

    Full Text Available The carbon dioxide reforming of methane was carried out over nickel catalysts supported on the gamma-Al2O3/CeO2 system prepared by wet impregnation. With the increase of the CeO2 weight in the catalyst, a higher stability was observed in the catalytic activity, together with an excellent resistance to carbon deposition and a better Ni dispersion. The catalysts were characterized by means of surface area measurements, TPR, H2 chemisorption, XRD, SEM, EDX, XPS and TEM. An interaction between Ni and CeO2 was observed to the Ni/CeO2 sample after activation in a H2 atmosphere above 300 ºC. Such behavior has a significantly influence on the catalytic activity.

  10. Incidência do pênfigo vulgar ultrapassa a do pênfigo foliáceo em região endêmica para pênfigo foliáceo: análise de série histórica de 21 anos

    OpenAIRE

    Gonçalves,Gilson Antonio Pereira; Brito,Moema Mignac Cumming; Salathiel,Adriana Martinelli; Ferraz,Thais Serraino; Alves,Domingos; Roselino,Ana Maria Ferreira

    2011-01-01

    FUNDAMENTO: Há dois tipos principais de pênfigo: pênfigo vulgar e pênfigo foliáceo. Nos últimos anos, mudanças clínicas e epidemiológicas relacionadas aos pênfigos têm sido observadas. OBJETIVOS: Teve-se por objetivo analisar uma série histórica de 21 anos de casos de pênfigo vulgar e pênfigo foliáceo no nordeste do estado de São Paulo, área endêmica para o pênfigo foliáceo. MÉTODOS: Neste estudo descritivo, foram analisados os dados relacionados à incidência anual e à idade de início do quad...

  11. Cetáceos de las aguas costeras del Pacífico norte y sur de Costa Rica

    Directory of Open Access Journals (Sweden)

    Damián Martínez-Fernández

    2011-03-01

    Full Text Available De las 29 especies de cetáceos presentes en Costa Rica, se han realizado investigaciones exhaustivas solamente para tres especies. Lo anterior evidencia la poca información general existente sobre cetáceos, a pesar de que Costa Rica posee un notable crecimiento de actividades de avistamiento. Debido al uso que se está generando en las zonas costeras, cada vez se hace más necesario determinar la ocurrencia de cetáceos en zonas de alta actividad turística, con el fin de proponer medidas de conservación. En el presente estudio, se determinaron variables ambientales que estaban relacionadas con la presencia de especies registradas, a partir de 166 avistamientos entre el 2005 y 2006. Las especies con mayor proporción de avistamientos fueron Stenella attenuata (68%, seguida por Megaptera novaeangliae (13% y Tursiops truncatus (10%. La presencia del delfín manchado se relaciona con cambios de salinidad y trasparencia del agua, mientras que la de la ballena jorobada estuvo relacionada con el oleaje y la temperatura superficial del agua. Se confirma la presencia de 7 especies de cetáceos en dos zonas costeras del Pacífico de Costa Rica, de las cuales tres están presentes a lo largo del año. Se encontraron variables ambientales relacionadas con la presencia de al menos dos especies.Inshore cetaceans from the North and South Pacific coast of Costa Rica. Twenty nine cetacean species occur in Costa Rican waters but extensive research has been conducted only for three species. The latter shows there is a lack of general and local information about these mammals, even when the country, has shown a remarkable growth in whale watching activities. The increasing use of marine resources in coastal areas has also developed the need to determine the occurrence of cetaceans in areas showing high tourist presence, in order to propose sound conservation measures. In this study, environmental variables were determined and subsequently related to the

  12. Memory resistive switching in CeO2-based film microstructures patterned by a focused ion beam

    DEFF Research Database (Denmark)

    Velichko, A.; Boriskov, P.; Grishin, A.

    2014-01-01

    ) with insulating properties and a semiconducting ormetallic lowresistance state (ON) with resistance ratios up to 104. The influence of micro-scaling and defects formed at the cell boundaries during etching on its electrical characteristics has been analyzed. The appearance of a switching channel at the moment......Heteroepitaxial CeO2 (80 nm)/La0.5Sr0.5CoO3 (500 nm) film structure has been pulsed laser deposited on a sapphire substrate. The Ag/CeO2 microjunctions patterned by a focused ion beam on a La0.5Sr0.5CoO3 film exhibit reproducible reversible switching between a high resistance state (OFF...... of the electrical forming, responsible for the memory effect, has been proved, along with a mechanism of a self-healing electrical breakdown. © 2014 Elsevier B.V. All rights reserved....

  13. Synthesis and characterization of biomorphic CeO2 obtained by using egg shell membrane as template

    Directory of Open Access Journals (Sweden)

    Marija Prekajski

    2014-06-01

    Full Text Available A new technology based on bio-templating approach was proposed in this paper. Egg-shell membrane (ESM has been employed as a natural biotemplate. Fibrous oxide ceramics was prepared by wet impregnation of biological template with water solution of cerium nitrate. The template was derived from membranes of fresh chicken eggs. Repeated impregnation, pyrolysis and final calcination in the range of 600 to 1200 °C in air resulted in template burnout and consolidation of the oxide layers. At low temperatures, the obtained products had structure which corresponded to the negative replication of biological templates. Unique bio-morphic CeO2 microstructures with interwoven networks were synthesized and characterized by scanning electron microscope (SEM and X-ray diffraction (XRD, whereas low-temperature nitrogen adsorption (BET method was used in order to characterize porous properties.

  14. The effects of physicochemical properties of CeO2 nanoparticles on toxicity to soil denitrification processes

    Science.gov (United States)

    Dahle, Jessica Teague

    The studies presented in this thesis identify the impact of NP CeO 2 on soil denitrifying microbial communities and reveal that physical and chemical characteristics including particle size, speciation, concentration, pH, and presence of ligands are key to predicting environmental fate and reactivity of NP CeO2 in the soil. A review of the literature in Chapter 1 revealed a widespread lack of toxicological information for soil exposures to NP CeO2. Soil denitrifying bacteria are a keystone species because they serve an important role in the global nitrogen cycle controlling the atmospheric nitrogen input. Soil denitrifiers are important to this study because the reducing conditions during denitrification could induce phase transformation of Ce(IV) to Ce(III), potentially influencing the toxicity of Ce. Cerium is well known for being the only lanthanide that is thermodynamically stable in both the trivalent and tetravalent state in low temperature geochemical environments. Using well characterized NP Ce(IV)O 2 as well as bulk soluble Ce(III), batch denitrification experiments were conducted to evaluate the toxicity of Ce species to the denitrifying community in a Toccoa sandy loam soil. The statistical analysis on the antimicrobial effect on soil denitrifiers was conducted using both steady-state evaluation and zero-order kinetic models in order to compare the toxicity of the Ce(III) species to the NPs. These studies, presented in Chapter 3, show that soluble Ce(III) is far more toxic than Ce(IV)O2 NPs when an equal total concentration of Ce is used, though both species exhibit toxicity to the denitrifiers via statistically significant inhibition of soil denitrification processes. Particle-size dependent toxicity, species-dependent toxicity, and concentration-dependent toxicity were all observed in this study for both the steady-state and the kinetic evaluations. The possibility of toxicity enhancement and diminishment via dissolution and ligand complexation

  15. Thermodynamic equilibrium calculations of sulfur poisoning in Ce-O-S and La-O-S systems

    Energy Technology Data Exchange (ETDEWEB)

    Karjalainen, Heidi; Lassi, Ulla; Rahkamaa-Tolonen, Katariina; Kroeger, Virpi; Keiski, Riitta L. [University of Oulu, Department of Process and Environmental Engineering, P.O. Box 4300, FIN-90014 Oulu (Finland)

    2005-02-28

    Sulfur poisoning is still a problem in many application areas of exhaust gas catalysts despite the fact that the sulfur levels, e.g. in gasoline are being continuously reduced. The aim of this study was to calculate thermodynamic equilibrium compositions of sulfur in Ce-O-S and La-O-S systems in the presence of precious metals (Pt, Pd, and Rh), which all were considered as bulk materials, in order to understand the experimentally observed sulfur poisoning under the real applications of exhaust gas catalysts. Depending on temperature and oxygen partial pressure, sulfur can be present in the form of sulfates, sulfides and oxysulfides. It is thermodynamically favorable that cerium oxide reacts with SO{sub 2} to form cerium sulfate at low temperatures and cerium oxysulfides at high temperatures. Lanthanum oxide reacts with SO{sub 2} to form sulfate under oxidizing conditions and sulfides under reducing conditions.

  16. Experimental study on polishing performance of CeO2 and nano-SiO2 mixed abrasive

    Science.gov (United States)

    He, Qiang

    2018-02-01

    In this paper, superfine SiO2 nanoparticles are utilized as composite abrasive additive to improve the polishing property of CeO2, which is prepared through chemical precipitation method by rare-earth chloride as raw materials, silicofluoric acid as fluoride, Na2CO3 as modifier, and NH4HCO3 as precipitator. XRD, SEM, particle size analyzer, and atomic force microscopy are applied to characterize the physical structure, morphology, and size distribution. Furthermore, the as-prepared composite abrasive is used to perform chemical mechanical polishing (CMP) experiment on K9 glass to identify the impact of different mass fraction of SiO2 on the CMP property of work materials. The results show that the composite abrasive contained 0.5% SiO2 has the best polishing property, the surface roughness, and material removal rate of glass after polishing can reach at 1.3157 nm and 22.6 nm/min, respectively.

  17. Voltage tunable dielectric properties of oxides at nanoscale: TiO2 and CeO2 as model systems

    Science.gov (United States)

    Prakash, T.; Tamil Selvan, A.; Suraiya Begum, S. N.

    2016-03-01

    Carrier transport through electrically active grain boundaries has been studied under biased condition using Solartron 1260 impedance/gain phase analyzer with an applied AC potential of 250 mV in the frequency range 1 Hz-1 MHz for nanocrystalline TiO2 and CeO2 as the model systems. Prior to the measurement both the materials were converted into cylindrical pellets with (8 mm diameter and 1 mm thick) by applying uni-axial pressure of 4 ton using a hydraulic press, then sintered at 300, 450 and 600 °C for 30 min for TiO2 sample and for the case of CeO2 it was done at 300, 600 and 900 °C for 30 min. Further, they were characterized using powder X-ray diffractometer (XRD) and transmission electron microscopy (TEM) to know the crystal structure, average crystallite size and morphology. The impedance measurements were performed at room temperature under applied DC bias voltages from 0 to 3 V in the periodic increment of 0.2 V. The observed applied bias voltage effect on dielectric constant of both the systems was analyzed with 'grain boundary double Schottky potential barrier height model' for different grain sizes. The percentage of voltage tunable dielectric constant (T%) as a function of frequency was estimated for all the grain sizes and it was found to be increase with reduction of grain size. Our experimental findings reveal the possibilities of utilizing these nanocrystals as a potential active material for phased array antenna since both the samples exhibits T% = 85% at 100 Hz frequency.

  18. In-Class Robot Flyby of an Endoplanet

    Science.gov (United States)

    Chadwick, A. J.; Capaldi, T.; Aurnou, J. M.

    2013-12-01

    For our Introduction to Computing class, we have developed a miniature robotic spacecraft mission that performs a flyby of an in-class 'endoplanet.' Our constructed endoplanet contains an internal dipole magnet, tilted with a dip angle that is unknown a priori. The spacecraft analog is a remotely controlled LEGO MINDSTORMS robot programmed using LabVIEW. Students acquire magnetic field data via a first spacecraft flyby past the endoplanet. This dataset is then imported into MATLAB, and is inverted to create a model of the magnet's orientation and dipole moment. Students use their models to predict the magnetic field profile along a different flyby path. They then test the accuracy of their models, comparing their predictions against the data acquired from this secondary flyby. We will be demonstrating this device at our poster in the Moscone Center.

  19. Learning Strategy in Class Management: A Reflection from Manado Case

    Science.gov (United States)

    Suardi Wekke, Ismail; Yandra, Alexander; Hamuddin, Budianto

    2017-12-01

    This article is a research conducted with qualitative approach with various case studies underlining a strategy that becomes the basis for classroom management. The article discusses and links to the learning revolution that becomes today’s demands, including a discussion that analyses the condition of learners. The article based its data preliminary study conducted in Manado in the province of North Sulawesi in Indonesia. This region has its own characteristics with the encounter of Muslims and the Protestant community for century. Due to its uniqueness 3 Moslem schools and 3 Protestant schools in Manado were selected to study. Data collection was conducted for a year, from May 2016 to April 2017. The study employ four stages research steps: identification, data collection, data validity checking, and directed discussion. The stages include observation and in-depth interviews and conducting focus group discussions. Two important thought about the essence of learning strategy and learning revolution in class were shared briefly within this article.

  20. Robust Strategy for Crafting Li5Cr7Ti6O25@CeO2Composites as High-Performance Anode Material for Lithium-Ion Battery.

    Science.gov (United States)

    Mei, Jie; Yi, Ting-Feng; Li, Xin-Yuan; Zhu, Yan-Rong; Xie, Ying; Zhang, Chao-Feng

    2017-07-19

    A facile strategy was developed to prepare Li 5 Cr 7 Ti 6 O 25 @CeO 2 composites as a high-performance anode material. X-ray diffraction (XRD) and Rietveld refinement results show that the CeO 2 coating does not alter the structure of Li 5 Cr 7 Ti 6 O 25 but increases the lattice parameter. Scanning electron microscopy (SEM) indicates that all samples have similar morphologies with a homogeneous particle distribution in the range of 100-500 nm. Energy-dispersive spectroscopy (EDS) mapping and high-resolution transmission electron microscopy (HRTEM) prove that CeO 2 layer successfully formed a coating layer on a surface of Li 5 Cr 7 Ti 6 O 25 particles and supplied a good conductive connection between the Li 5 Cr 7 Ti 6 O 25 particles. The electrochemical characterization reveals that Li 5 Cr 7 Ti 6 O 25 @CeO 2 (3 wt %) electrode shows the highest reversibility of the insertion and deinsertion behavior of Li ion, the smallest electrochemical polarization, the best lithium-ion mobility among all electrodes, and a better electrochemical activity than the pristine one. Therefore, Li 5 Cr 7 Ti 6 O 25 @CeO 2 (3 wt %) electrode indicates the highest delithiation and lithiation capacities at each rate. At 5 C charge-discharge rate, the pristine Li 5 Cr 7 Ti 6 O 25 only delivers an initial delithiation capacity of ∼94.7 mAh g -1 , and the delithiation capacity merely achieves 87.4 mAh g -1 even after 100 cycles. However, Li 5 Cr 7 Ti 6 O 25 @CeO 2 (3 wt %) delivers an initial delithiation capacity of 107.5 mAh·g -1 , and the delithiation capacity also reaches 100.5 mAh g -1 even after 100 cycles. The cerium dioxide modification is a direct and efficient approach to improve the delithiation and lithiation capacities and cycle property of Li 5 Cr 7 Ti 6 O 25 at large current densities.

  1. Role of CeO2 promoter in NiO/α-Al2O3 catalyst for dry reforming of methane

    Science.gov (United States)

    Loc, Luu Cam; Phuong, Phan Hong; Tri, Nguyen

    2017-09-01

    A series of Ni/α-Al2O3 (NiAl) catalysts promoted by CeO2 was prepared by co-impregnation methods with content of (NiO+CeO2) being in the range of 10-30 wt%. The NiO:CeO2 weight ratio was fluctuated at 1:1, 1:2 and 1:3. Several techniques, including X-ray powder diffraction (XRD), Hydrogen temperature-programmed reduction (H2-TPR), and transmission electron microscopy (TEM) were used to investigate catalysts' physico-chemical properties. The activity of these catalysts in dry reforming of CH4 was investigated at temperature range of 550-800 °C. The results revealed that the most suitable CeO2 promoted Ni catalyst contained 20 wt% of (NiO+CeO2) and NiO:CeO2 weight ratio of 1:2. The best catalytic performance of catalyst [20(1Ni2Ce)Al] due to a better reducibility resulted in a higher amount of free small particle NiO. At 700 °C and CH4:CO2 molar ratio of 1:1, the conversion of CH4 and CO2 on the most suitable CeO2 promoted Ni catalyst reached 86% and 67%, respectively; H2 and CO selectivity of 90% and H2:CO molar ratio of 1.15 were obtained. Being similar to MgO [1], promoter CeO2 could improve catalytic activity of Ni/α-Al2O3 catalyst at a lower range of temperature. Besides, both MgO and CeO2 had a great impact on improving coke resistance of Ni catalysts. At higher temperature, the role of CeO2 as well as MgO in preventing coke formation on catalyst was clarified by temperature-programmed oxidation (TPO) technique. Coke amount formed after 30-h TOS on 20(1Ni2Ce) catalyst was found to be 22.18 mgC/gcat, being less than on non-promoted catalyst (36.75 mgC/gcat), but more than on 20(1Ni2Mg)Al one (5.25 mgC/gcat).

  2. Mining amino acid association patterns in class B GPCRs.

    Science.gov (United States)

    Kumari, Tannu; Pardasani, Kamal Raj

    2015-01-01

    Class B GPCR family is a small group of receptors which are activated by peptides of intermediate length that range from 30 to 40 amino acid residues including hormones, neuropeptides and autocrine factors that mediate diverse physiological functions. They are involved in physiological processes like glucose homeostasis (glucagon and glucagon-like peptide-1), calcium homeostasis and bone turnover (parathyroid hormone and calcitonin), and control of the stress axis (corticotropin-releasing factor). Most of the GPCR structures and their functions are still unknown. Thus, the study of amino acid association patterns can be useful in prediction of their structure and functions. In view of above, in this paper, an attempt has been made to explore amino acid association patterns in class B GPCRs and their relationships with secondary structures and physiochemical properties. The fuzzy association rule mining is employed to take care of uncertainty due to variation in length of sequences. The association rules have been generated with the help of patterns discovered in the sequences.

  3. Relative solubility of cations in Class F fly ash.

    Science.gov (United States)

    Kim, Ann G; Kazonich, George; Dahlberg, Michael

    2003-10-01

    Coal utilization byproducts (CUB), such as fly ash, contain cations that may be released during exposure to fluids such as acid rain or acid mine drainage. Researchers at the Department of Energy's National Energy Technology Laboratory (DOE/NETL) have conducted a long-term column leaching study of 32 Class F fly ash samples from pulverized coal (PC) combustion, and quantified the release of 19 cations in four leachants with a pH between 1.2 and 12. The relative solubility (M(L/T)) of each cation was defined as the total mass leached (M(L)) relative to the concentration (M(T)) of that element in the fly ash sample. A frequency distribution of relative solubility values was computed with ranges defined as insoluble, slightly soluble, moderately soluble, and very soluble. On the basis of this sample set, Ba, Cd, Fe, Pb, Sb, and Se in PC fly ash are insoluble. The elements Al, Be, Ca, Co, Cr, Cu, K, Mg, Mn, Na, Ni, and Zn are slightly to moderately acid soluble. Only Ca and Na are water soluble; As and Ca are soluble in the basic solution, The results of this study indicate that the extent to which cations in Class F PC fly ash can be leached by naturally occurring fluids is very limited.

  4. Promotional effect of Al2O3 on WO3/CeO2-ZrO2 monolithic catalyst for selective catalytic reduction of nitrogen oxides with ammonia after hydrothermal aging treatment

    Science.gov (United States)

    Xu, Haidi; Liu, Shuang; Wang, Yun; Lin, Qingjin; Lin, Chenlu; Lan, Li; Wang, Qin; Chen, Yaoqiang

    2018-01-01

    Hydrothermal stability of catalysts for selective catalytic reduction of NOx with NH3 (NH3-SCR) has always been recognized as a challenge in development of candidate catalysts for applications in diesel engine emissions. In this study, Al2O3 was introduced into CeO2-ZrO2 to improve the NH3-SCR activity of WO3/CeO2-ZrO2 after hydrothermal aging (HA) treatment at 800 °C for 12 h. The activity results indicated that the NH3-SCR activity of WO3/CeO2-ZrO2-HA was obviously improved in the whole reaction temperature range after doping Al2O3 into CeO2-ZrO2, for example, the average and maximum NOx conversion were separately increased by ca. 20% and 25% after HA treatment. XRD, Raman, TEM and EDX results revealed that the introduction of Al2O3 inhibited the sintering and agglomeration of CeO2-ZrO2 and WO3 and the formation of Ce2(WO4)3 after HA treatment. Accordingly, WO3/CeO2-ZrO2-Al2O3-HA showed remarkably improved structural stability and reducibility, increased surface acidity, and facilitated the reactivity between adsorbed NH3 and nitrate species, which together contributed to its better catalytic performance after hydrothermal aging treatment.

  5. Trifluoroacetate metal organic deposition derived (Y0.77Gd0.23)Ba2Cu3O y films on CeO2 buffered R-plane Al2O3 substrates

    Science.gov (United States)

    Sakuma, Keita; Sato, Michio; Miura, Masashi

    2018-03-01

    (Y0.77Gd0.23)Ba2Cu3O y [(Y,Gd)BCO] films were grown on CeO2 buffered R-plane sapphire (R-Al2O3) substrates using trifluoroacetate metal organic deposition (TFA-MOD). Annealing of the CeO2 buffered R-Al2O3 substrates was performed to control the crystallinity and surface morphology of the CeO2 buffer layer. The annealing treatment led to a significant improvement in the crystallinity and surface morphology of the CeO2 buffer layer. A (Y,Gd)BCO film grown on the CeO2 buffer layer with high crystallinity and an atomically flat surface exhibited high self-field (at 77 K) and in-field (at 20 K, 9 T, μ0 H∥c) critical current densities (J c). Annealing of the CeO2 buffer layer thus enabled enhancement of not only the self-field J c for the (Y,Gd)BCO film but also the in-field J c.

  6. Interventional neuroradiology

    International Nuclear Information System (INIS)

    Mehta, B.A.; Quint, D.J.; Sanders, W.P.; Patel, S.C.; Boulos, R.S.; Burke, T.H.

    1987-01-01

    This presentation reviews the authors' angiographic approach to interventional cases and demonstrates examples of procedures we have performed including preoperative embolizations (dural, arteriovenous malformations, meningioma, juvenile angiofibroma, gliosarcoma, glomus tympanicum, hemangiopericytoma, and spinal hemangioma), therapeutic interventions (balloon occlusion of cavernous-carotid and vertebral fistulas, intracranial and extracranial aneurysms, and angioplasty of vertebral, external carotid, and subclavian arteries), and pain management (alcohol injection of spine metastases). Potential and actual complications are reviewed

  7. Hydrophilic CeO2 nanocubes protect pancreatic β-cell line INS-1 from H2O2-induced oxidative stress

    Science.gov (United States)

    Lyu, Guang-Ming; Wang, Yan-Jie; Huang, Xue; Zhang, Huai-Yuan; Sun, Ling-Dong; Liu, Yan-Jun; Yan, Chun-Hua

    2016-04-01

    Oxidative stress plays a key role in the occurrence and development of diabetes. With their unique redox properties, CeO2 nanoparticles (nanoceria) exhibit promising potential for the treatment of diabetes resulting from oxidative stress. Here, we develop a novel preparation of hydrophilic CeO2 nanocubes (NCs) with two different sizes (5 nm and 25 nm) via an acetate assisted hydrothermal method. Dynamic light scattering, zeta potential measurements and thermogravimetric analyses were utilized to investigate the changes in the physico-chemical characteristics of CeO2 NCs when exposed to in vitro cell culture conditions. CCK-8 assays revealed that the CeO2 NCs did not impair cell proliferation in the pancreatic β-cell line INS-1 at the highest dose of 200 μg mL-1 over the time scale of 72 h, while being able to protect INS-1 cells from H2O2-induced cytotoxicity even after protein adsorption. It is also noteworthy that nanoceria with a smaller hydrodynamic radius exhibit stronger antioxidant and anti-apoptotic effects, which is consistent with their H2O2 quenching capability in biological systems. These findings suggest that nanoceria can be used as an excellent antioxidant for controlling oxidative stress-induced pancreatic β-cell damage.Oxidative stress plays a key role in the occurrence and development of diabetes. With their unique redox properties, CeO2 nanoparticles (nanoceria) exhibit promising potential for the treatment of diabetes resulting from oxidative stress. Here, we develop a novel preparation of hydrophilic CeO2 nanocubes (NCs) with two different sizes (5 nm and 25 nm) via an acetate assisted hydrothermal method. Dynamic light scattering, zeta potential measurements and thermogravimetric analyses were utilized to investigate the changes in the physico-chemical characteristics of CeO2 NCs when exposed to in vitro cell culture conditions. CCK-8 assays revealed that the CeO2 NCs did not impair cell proliferation in the pancreatic β-cell line INS-1 at

  8. Development of One Meter Long Double-Sided CeO2 Buffered Ni-5at.%W Templates by Reel-to-Reel Chemical Solution Deposition Route

    DEFF Research Database (Denmark)

    Yue, Zhao; Konstantopoulou, K.; Wulff, Anders Christian

    2013-01-01

    High performance long-length coated conductors fabricated using various techniques have attracted a lot of interest recently. In this work, a reel-to-reel design for depositing double-sided coatings on long-length flexible metallic tapes via a chemical solution method is proposed and realized......%W template. The CeO2 films on both sides exhibit a dense, crack-free morphology, and a high fraction of cube texture on the surface. Homogeneity studies on global texture over the length also reveal that the average full width at half maximum values of the in-plane and out-of-plane orientation on the CeO2......, demonstrating the possibility of producing long-length texture templates for coated conductors by this low cost deposition route....

  9. Additive Manufacturing of a 316L Steel Matrix Composite Reinforced with CeO2 Particles: Process Optimization by Adjusting the Laser Scanning Speed

    Directory of Open Access Journals (Sweden)

    Omar O. Salman

    2018-02-01

    Full Text Available The synthesis of novel materials by additive manufacturing requires the optimization of the processing parameters in order to obtain fully-dense defect-free specimens. This step is particularly important for processing of composite materials, where the addition of a second phase may significantly alter the melting and solidification steps. In this work, a composite consisting of a 316L steel matrix and 5 vol.% CeO2 particles was fabricated by selective laser melting (SLM. The SLM parameters leading to a defect-free 316L matrix are not suitable for the production of 316L/CeO2 composite specimens. However, highly-dense composite samples can be synthesized by carefully adjusting the laser scanning speed, while keeping the other parameters constant. The addition of the CeO2 reinforcement does not alter phase formation, but it affects the microstructure of the composite, which is significantly refined compared with the unreinforced 316L material.

  10. Changing organizational culture: using the CEO cancer gold standard policy initiatives to promote health and wellness at a school of public health.

    Science.gov (United States)

    Towne, Samuel D; Anderson, Kelsey E; Smith, Matthew Lee; Dahlke, Deborah Vollmer; Kellstedt, Debra; Purcell, Ninfa Pena; Ory, Marcia G

    2015-09-03

    Worksite wellness initiatives for health promotion and health education have demonstrated effectiveness in improving employee health and wellness. We examined the effects of a multifaceted health promotion campaign on organizational capacity to meet requirements to become CEO Cancer Gold Standard Accredited. We conducted an online survey to assess perceived organizational values and support for the five CEO Cancer Gold Standard Pillars for cancer prevention: tobacco cessation; physical activity; nutrition; cancer screening and early detection; and accessing information on cancer clinical trials. Baseline and follow-up surveys were sent 6-months apart to faculty, staff, and students at a school of public health to test the impact of a multifaceted health promotion campaign on perceived organizational change. Descriptive analyses were used to characterize percent improvement. Multivariate logistic regression analyses were used to control for participants' university status. The current organizational culture highly supported tobacco cessation at both time points. Significant improvements (p initiatives.

  11. Angle dependence of Shubnikov-de Haas effect of filled skutterudite compounds CeOs4Sb12 and NdOs4Sb12

    Science.gov (United States)

    Ho, P.-C.; Singleton, J.; Balakirev, F. F.; Maple, M. B.; Yanagisawa, T.

    Intriguingly the three filled skutterudite compounds CeOs4Sb12, PrOs4Sb12, and NdOs4Sb12 span the range from the Kondo insulator with a 1K antiferromagnetic (AFM) order, a 1.85K unconventional superconductor (SC), to a 1K mean-field type ferromagnet (FM), indicating that they reside near quantum critical points of AFM and FM with unconventional SC induced within this regime. Therefore, understanding the Fermi surfaces of NdOs4Sb12 and CeOs4Sb12 becomes crucial in elucidating the superconducting pairing mechanism in PrOs4Sb12. Penetration depths of single crystals of CeOs4Sb12 and NdOs4Sb12 were measured for temperatures down to 1.3 K and magnetic fields up to 60 tesla by using proximity detection oscillators in the Pulsed Field Facility at NHMFL/LANL. Angle dependence of Shubnikov-de Haas oscillations was detected for rotating the field with respect to the crystalline orientations [010] and [0-10]. The results indicate that LaOs4Sb12, PrOs4Sb12 and NdOs4Sb12 have similar Fermi surfaces. The Fermi surface of CeOs4Sb12 is rather isotropic and is much different from the other three compounds. Research at CSU-Fresno is supported by NSF DMR-1506677; at UCSD by NSF DMR-1206553 and US DOE DE-FG02-04ER46105; at NHMFL by DOE, NSF, and FL; at Hokkaido U by Graint-In-Aid No. 2600342,Jpn.

  12. Separation of carrier free 152,153Dy and 152,153Tb produced in 16O irradiated CeO2 target matrix

    International Nuclear Information System (INIS)

    Nayak, Dalia; Lahiri, Susanta; Das, N.R.; Das, S.K.; Ramaswami, A.; Manohor, S.B.

    1999-01-01

    Heavy ion activation of nat CeO 2 with ∼ 80 MeV 16 O results in the formation of carrier free radioisotopes, 152,153 Dy and its daughter product, 152,153 Tb, in the matrix. The liquid cation exchanger, HDEHP, has effectively been utilised as an extractant in the separation of the carrier free radioisotopes from the bulk target matrix. (author)

  13. Ru 4 ion in CeO 2 (Ce 0.95 Ru 0.05 O 2− ): A non-deactivating ...

    Indian Academy of Sciences (India)

    A new WGS catalyst, Ce1−RuO2− (0 ≤ ≤ 0.1) was prepared by hydrothermal method using melamine as a complexing agent. The Catalyst does not require any pre-treatment. Among the several compositions prepared and tested, Ce0.95Ru0.05O2− (5% Ru4+ ion substituted in CeO2) showed very high WGS ...

  14. Metabolomic effects in HepG2 cells exposed to CeO2, SiO2 and CuO nanomaterials.

    Science.gov (United States)

    To better assess potential hepatotoxicity of nanomaterials, human liver HepG2 cells were exposed for three days to 5 different CeO2 (either 30 or 100 ug/ml), 3 SiO2 based (30 ug/ml) or 1 CuO (3 ug/ml) nanomaterials with dry primary particle sizes ranging from 15 to 213 nm. Metab...

  15. The Effect of CEO Duality, Board Composition and Board Size on Organizational Performance of Companies Listed on the Kuala Lumpur Stock Exchange

    OpenAIRE

    Muhammad, Nordin; Harjito, D. Agus; Muhammad, Junaina

    2009-01-01

    This study examined the effect of CEO duality, board composition and board size on organizational performance of Bourse Malaysia or Kuala Lumpur Stock Exchange (KLSE) listed companies. For comparison purpose, this study examined these variables for main board companies as the proxy of large size companies, second board as the proxy for small size companies, and the whole market as proxy for developing country. This study employed 196 companies selected from the main board (96) and the second ...

  16. The Effect of CEO Duality, Board Composition and Board Size on Organizational Performance of Companies Listed on the Kuala Lumpur Stock Exchange

    OpenAIRE

    Muhammad, Nordin; Harjito, D. Agus; Muhammad, Junaina

    2005-01-01

    This study examined the effect of CEO duality, board composition and board size on organizational performance of Bourse Malaysia or Kuala Lumpur Stock Exchange (KLSE) listed companies. For comparison purpose, this study examined these variables for main board companies as the proxy of large size companies, second board as the proxy for small size companies, and the whole market as proxy for developing country. This study employed 196 companies selected from the main board (96) and the second ...

  17. Metabolomic effects of CeO2, SiO2 and CuO metal oxide nanomaterials on HepG2 cells

    Science.gov (United States)

    To better assess potential hepatotoxicity of nanomaterials, human liver HepG2 cells were exposed for 3 days to five different CeO2 (either 30 or 100 μg/ml), 3 SiO2 based (30 μg/ml) or 1 CuO (3 μg/ml) nanomaterials with dry primary particle sizes ranging from 15 to 213 nm. Metabol...

  18. One-pot hydrothermal growth of raspberry-like CeO2 on CuO microsphere as copper-based catalyst for Rochow reaction

    International Nuclear Information System (INIS)

    Jin, Zheying; Li, Jing; Shi, Laishun; Ji, Yongjun; Zhong, Ziyi; Su, Fabing

    2015-01-01

    Graphical abstract: - Highlights: • Ce–CuO composites were prepared via a one-pot and template-free hydrothermal method. • Ce–CuO consisted of raspberry-like CeO 2 particles dispersed on porous CuO microspheres. • CuO microspheres were formed by self-assembly of nanorods. • Ce–CuO exhibited superior catalytic activity for dimethyldichlorosilane synthesis. - Abstract: In this work, we prepared a novel structure comprising of raspberry-like CeO 2 deposited on CuO microspheres (Ce–CuO) for Rochow reaction. The synthesis was carried out via a facile one-pot hydrothermal reaction without using any template, in which, the basic copper carbonate microspheres were first formed via self-assembly of basic copper carbonate nanorods, followed with deposition of cerium hydroxide. After calcination, they were transformed into Ce–CuO but still maintained the hierarchical structure, and meanwhile, mesoporous structure was formed (for simplicity, we will only state them as metal oxide in the following context). The samples were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), and scanning electron microscopy (SEM) techniques. When used as a Cu-based catalyst, Ce–CuO exhibited superior catalytic property to the single CuO, CeO 2 and their physically mixture in the Rochow reaction with dimethyldichlorosilane (M2) selectivity increased from ca. 65 to 83.7%. The higher M2 selectivity of Ce–CuO is mainly due to its larger surface area and the synergistic effect between CuO and CeO 2 . This work demonstrates that catalytic performance of the Cu-based can be improved by adding Ce rare-earth element and by carefully controlling their structures.

  19. The On Line Validation Exercise (OLIVE) Tool: a CEOS/LPV initiative for validation of global land products

    Science.gov (United States)

    Weiss, M.; Baret, F.; Block, T.; Koetz, B.; Burini, A.; Fernandes, R. A.; Nightingale, J. M.

    2012-12-01

    The OLIVE (On Line Interactive Validation Exercise) system enables transparent and traceable validation and inter-comparison of EO land products (LAI, FAPAR, FCOVER). The ultimate objective of OLIVE is to provide consistent and reliable information on the accuracy and associated uncertainty of EO products. The validation exercise follows the guidelines proposed by CEOS/LPV and allows for regular updates when new versions or products are available. OLIVE is accessible to the whole EO community which can run validation exercises, including existing or new products. The validation process involves several criterions listed hereafter: (i) continuity of products, i.e. evaluation of the spatial and temporal distribution of missing values,(ii) accuracy assessment achieved by comparing the product value derived from satellite observations to ground measurements of the corresponding biophysical variable (i.e. direct validation) (iii) precision assessment, mainly regarding the temporal and spatial consistency, including the long term temporal stability mandatory for several applications, and (iv) intercomparison between currently existing products. OLIVE is a web platform and provides three main functionalities: 1. Easy and transparent access to validation exercise results, including product definition, description of the validation process and associated data. 2. Evaluate new EO products/versions developed by any producer. Formats required for the candidate input product are described in details. The validation can be run in two modes: (i) the 'private' mode for which the validation results are only visible to this user. This mode is dedicated to perform tests when the product may not be mature enough for public scrutiny; (ii) the 'public' mode, for more mature products, where the results are published on the system and accessible to the community. In the latter case, the data used for the validation are stored on the system and available to the community for inter

  20. Financial restatement and firm performance in family controlled and CEO duality companies: evidence from post 2007 Malaysian Code of Corporate Governance

    Directory of Open Access Journals (Sweden)

    Chin Sok Fun

    2017-01-01

    Full Text Available Do financial restatements dampen firm performance? One argument about this is that restatements hurt investor confidence in the credibility of a firm’s disclosure, resulting in a decline in demand for the firm’s securities, thereby, leading to a significant drop in asset price. On the other hand, agency theory suggests that family ownership could have potential benefits to a firm’s performance. An increase in family ownership will have a greater concern for reputation to the controlling family in producing high quality accounting information and, thereby, reduce the likelihood of financial restatements. We evaluate these arguments by distinguishing the effects of restatements on firm performance under two corporate governance environments; family-controlled and CEO duality companies. Based on a sample of Malaysian listed companies in 2008 after the post MCCG 2007 initiative, our findings suggest that (1 restatements dampen firm performance, (2 the dampening impacts of restatements are completely mitigated in family-controlled companies, and (3 the dampening effects are more pronounced in non-family controlled companies than family-controlled companies in non-CEO duality companies. Using this evidence, we recommend that Malaysian regulators develop policies that are unique to the Malaysian markets so as to curtail accounting irregularities. They should reconsider the relevance of requiring CEO nonduality as a practice of good corporate governance and encourage more investment in family-controlled companies.

  1. The CEOS-Land Surface Imaging Constellation Portal for GEOSS: A resource for land surface imaging system information and data access

    Science.gov (United States)

    Holm, Thomas; Gallo, Kevin P.; Bailey, Bryan

    2010-01-01

    The Committee on Earth Observation Satellites is an international group that coordinates civil space-borne observations of the Earth, and provides the space component of the Global Earth Observing System of Systems (GEOSS). The CEOS Virtual Constellations concept was implemented in an effort to engage and coordinate disparate Earth observing programs of CEOS member agencies and ultimately facilitate their contribution in supplying the space-based observations required to satisfy the requirements of the GEOSS. The CEOS initially established Study Teams for four prototype constellations that included precipitation, land surface imaging, ocean surface topography, and atmospheric composition. The basic mission of the Land Surface Imaging (LSI) Constellation [1] is to promote the efficient, effective, and comprehensive collection, distribution, and application of space-acquired image data of the global land surface, especially to meet societal needs of the global population, such as those addressed by the nine Group on Earth Observations (GEO) Societal Benefit Areas (SBAs) of agriculture, biodiversity, climate, disasters, ecosystems, energy, health, water, and weather. The LSI Constellation Portal is the result of an effort to address important goals within the LSI Constellation mission and provide resources to assist in planning for future space missions that might further contribute to meeting those goals.

  2. Acetic Acid Reforming over Rh Supported on La2O3/CeO2-ZrO2: Catalytic Performance and Reaction Pathway Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lemonidou, Angeliki A.; Vagia, Ekaterini C.; Lercher, Johannes A.

    2013-07-11

    Reforming of acetic acid was investigated on Rh supported on CeO2-ZrO2 modified with 3 wt % La. The active catalyst converted acetic acid to H-2-rich gas and hardly formed coke. The low rate of coke formation is concluded to be related to the presence of redox-active oxygen limiting the concentration of coke precursors. Temperature-programmed O-18(2)) isotope exchange measurements showed that the La2O3 and Rh enhanced the mobility of lattice oxygen compared with that of the parent CeO2-ZrO2. Ketonization and decarboxylation of acetic acid are the dominating reactions over the latter up to 600 degrees C, whereas above 600 degrees C, steam reforming and water gas shift also contribute. Over 0.5 wt % Rh on La2O3/CeO2-ZrO2, reforming and water gas shift reactions dominate, even below 300 degrees C, producing mostly H-2 and CO2. Using isotope labeling, it is shown that acetic acid adsorbs dissociatively on Rh, forming acetates, which sequentially decarboxylate and form surface methyl groups. The latter are in turn converted to CO, CO2, and H-2.

  3. Oxygen and chlorine evolution on RuO2 + TiO2 + CeO2 + Nb2O5 mixed oxide electrodes

    International Nuclear Information System (INIS)

    Santana, Mario H.P.; Faria, Luiz A. de

    2006-01-01

    A systematic investigation was conducted on the mechanism and electrocatalytic properties of O 2 and Cl 2 evolution on mixed oxide electrodes of nominal composition: Ti/[Ru (0.3) Ti (0.6) Ce (0.1-x) ]O 2 [Nb 2 O 5 ] (x) (0 ≤ x ≤ 0.1). For the oxygen evolution, a 30 mV Tafel slope is obtained in the presence of CeO 2 , while in its absence a 40 mV coefficient is observed. The intrinsic electrocatalytic activity is mainly due to electronic factors, as result of the synergism between Ru and Ce oxides. For chlorine evolution, the Tafel slope (30 mV) is independent on oxide composition. The best global electrocatalytic activity for ClER was observed in the absence of Nb 2 O 5 additive. Variation of the voltammetric charge throughout the experiments confirms high CeO 2 content compositions are fragile, due mainly to the porosity caused by CeO 2 presence. On the other hand, Nb 2 O 5 addition decreases considerably this instability

  4. CeO2-CuO/Cu2O/Cu monolithic catalysts with three-kind morphologies Cu2O layers for preferential CO oxidation

    Science.gov (United States)

    Jing, Guojuan; Zhang, Xuejiao; Zhang, Aiai; Li, Meng; Zeng, Shanghong; Xu, Changjin; Su, Haiquan

    2018-03-01

    The supports of copper slices with three-kind morphologies Cu2O layers were prepared by the hydrothermal method. The Cu2O layers are rod-like structure, three-dimensional reticular and porous morphology as well as flower-like morphology, respectively. The CeO2-CuO/Cu2O/Cu monolithic catalysts present porous and network structure or foam morphology after loading CeO2 and CuO. Cu and Ce elements are uniformly dispersed onto the support surface. It is found that the monolithic catalyst with flower-like Cu2O layer displays better low-temperature activity because of highly-dispersed CuO and high Olatt concentration. The monolithic catalysts with rod-like or reticular-morphology Cu2O layers present high-temperature activity due to larger CuO crystallite sizes and good synergistic effect at copper-ceria interfacial sites. The as-prepared CeO2-CuO/Cu2O/Cu monolithic catalysts show good performance in the CO-PROX reaction. The generation of Cu2O layers with three-kind morphologies is beneficial to the loading and dispersion of copper oxides and ceria.

  5. Do similarities or differences between CEO leadership and organizational culture have a more positive effect on firm performance? A test of competing predictions.

    Science.gov (United States)

    Hartnell, Chad A; Kinicki, Angelo J; Lambert, Lisa Schurer; Fugate, Mel; Doyle Corner, Patricia

    2016-06-01

    This study examines the nature of the interaction between CEO leadership and organizational culture using 2 common metathemes (task and relationship) in leadership and culture research. Two perspectives, similarity and dissimilarity, offer competing predictions about the fit, or interaction, between leadership and culture and its predicted effect on firm performance. Predictions for the similarity perspective draw upon attribution theory and social identity theory of leadership, whereas predictions for the dissimilarity perspective are developed based upon insights from leadership contingency theories and the notion of substitutability. Hierarchical regression results from 114 CEOs and 324 top management team (TMT) members failed to support the similarity hypotheses but revealed broad support for the dissimilarity predictions. Findings suggest that culture can serve as a substitute for leadership when leadership behaviors are redundant with cultural values (i.e., they both share a task- or relationship-oriented focus). Findings also support leadership contingency theories indicating that CEO leadership is effective when it provides psychological and motivational resources lacking in the organization's culture. We discuss theoretical and practical implications and delineate directions for future research. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  6. The use of CeO2-Co3O4 oxides as a catalyst for the reduction of N2O emission

    Directory of Open Access Journals (Sweden)

    Rajska Maria

    2016-01-01

    Full Text Available The morphological characterization of a series of cobalt-cerium oxide composites prepared by the deposition of CeO2 onto Co3O4 powder with a molar ratio of cerium oxide to Co3O4 in the range of 0 to 1 was performed. The powders were also impregnated with a solution of K2CO3 to obtain the theoretical content of potassium atoms 2at·nm−2. To investigate the effect of adding specific amount of CeO2 on the catalytic activity, the X-ray diffraction, SEM-EDX, laser particle size distribution and BET surface area measurements were used. The catalysts were tested through the low-temperature decomposition of nitrous oxide in the temperature range of 50°C to 700°C. The addition of CeO2 and K always moved the temperature of a complete N2O conversion towards lower temperatures (480°C-540°C to 340°C-420°C. The best catalytic properties were shown by the samples in which the ratio of cerium oxide to cobalt oxide ranged from 0.4 to 0.7.

  7. Microleakage of four composite resin systems in class II restorations.

    Science.gov (United States)

    Majeed, A; Osman, Y I; Al-Omari, T

    2009-11-01

    To compare the microleakage at the enamel and dentine/cementum margins of three nanocomposites and a microhybrid composite in Class II restorations. Four light-cured dental resin restorative materials in combination with their respective bonding agents were investigated. Eighty non-carious, extracted human molars were divided into 4 groups of 20 teeth each. The apices of the teeth were sealed with a resin modified glass ionomer cement. Standardized Class II slot cavities were prepared on the proximal surfaces of each tooth. Each group had an equal number of cavities with gingival margins on enamel and on dentine/cementum. Restorations were placed as indicated: Group 1 (G1): Ceram-X mono/Prime & Bond NT (Dentsply), G2: Premise/ OptiBond Solo Plus (Kerr), G3: Grandio/Admira Bond (VOCO), G4: Z100/Adper Scotchbond Multi-Purpose (3M ESPE). After thermocycling and immersion in 0.5% methylene blue dye solution, the teeth were sectioned and dye penetration was scored on a scale of 0 to 3 on both the enamel and dentine/cementum margins. The data were analyzed using a Kruskal-Wallis one way ANOVA and Mann-Whitney U test of ranks (significance at p Grandio/Admira Bond showed significantly lower microleakage when compared to the other materials tested while Z100/Adper Scotchbond Multi-Purpose showed the largest microleakage (p Grandio/Admira Bond showing the least microleakage when compared to the other three materials tested. At the enamel margins, all materials tested performed reasonably well.

  8. L-Arginine-Triggered Self-Assembly of CeO2 Nanosheaths on Palladium Nanoparticles in Water.

    Science.gov (United States)

    Wang, Xiao; Zhang, Yibo; Song, Shuyan; Yang, Xiangguang; Wang, Zhuo; Jin, Rongchao; Zhang, Hongjie

    2016-03-24

    Pd@CeO2 core-shell nanostructures with a tunable Pd core size, shape, and nanostructure as well as a tunable CeO2 sheath thickness were obtained by a biomolecule-assisted method. The synthetic process is simple and green, as it involves only the heating of a mixture of Ce(NO3 )3 , l-arginine, and preformed Pd seeds in water without additives. Importantly, the synthesis is free of thiol groups and halide ions, thus providing a possible solution to the problem of secondary pollution by Pd nanoparticles in the sheath-coating process. The Pd/CeO2 nanostructures can be composited well with γ-Al2 O3 to create a heterogeneous catalyst. In subsequent tests of catalytic NO reduction by CO, Pd@CeO2 /Al2 O3 samples based on Pd cubes (6, 10, and 18 nm), Pd octahedra (6 nm), and Pd cuboctahedra (9 nm) as well as a simply loaded Pd cube (6 nm)-CeO2 /Al2 O3 sample were used as catalysts to investigate the effects of the Pd core size and shape and the hybrid nanostructure on the catalytic performance. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. ROS mediated malignancy cure performance of morphological, optical, and electrically tuned Sn doped CeO2 nanostructures

    Directory of Open Access Journals (Sweden)

    Fazal Abbas

    2017-09-01

    Full Text Available To grapple with cancer, implementation of differentially cytotoxic nanomedicines have gained prime attention of the researchers across the globe. Now, ceria (CeO2 at nanoscale has emerged as a cut out therapeutic agent for malignancy treatment. Keeping this in view, we have fabricated SnxCe1-xO2 nanostructures by facile, eco-friendly, and biocompatible hydrothermal method. Structural examinations via XRD and FT-IR spectroscopy have revealed single phase cubic-fluorite morphology while SEM analysis has depicted particle size ranging 30-50nm for pristine and doped nanostructures. UV-Vis spectroscopy investigation explored that Sn doping significantly tuned the band gap (eV energies of SnxCe1-xO2 nanostructures which set up the base for tremendous cellular reactive oxygen species (ROS generations involved in cancer cells’ death. To observe cytotoxicity, synthesized nanostructures were found selectively more toxic to neuroblastoma cell lines as compared to HEK-293 healthy cells. This study anticipates that SnxCe1-xO2 nanostructures, in future, might be used as nanomedicine for safer cancer therapy.

  10. Static force fields simulations of reduced CeO2 (110) surface: Structure and adsorption of H2O molecule

    Science.gov (United States)

    Vives, Serge; Meunier, Cathy

    2018-02-01

    The CeO2(110) surface properties are largely involved in the catalysis, energy and biological phenomenon. The Static Force Fields simulations are able to describe large atomic systems surface even if no information on the electronic structure can be obtained. We employ those simulations to study the formation of the neutral 2 CeCe‧ VO•• cluster. We focus on seven different cluster configurations and find that the defect formation energy is the lower for the 1N-2N configurations. Two geometries are possible, as it is the case for the ab initio studies, the in plane and the more stable bridging one. We evidence the modifications of the surface energy and the Potential Energy Surface due to the presence of the 2 CeCe‧ VO•• defect. The physical adsorption of a water molecule is calculated and the geometry described for all the cluster configurations. The H2O molecule physisorption stabilizes the Ce(110) surface and the presence of the 2 CeCe‧ VO•• defect increases this effect.

  11. Electrochemical reduction of CerMet fuels for transmutation using surrogate CeO2-Mo pellets

    Science.gov (United States)

    Claux, B.; Souček, P.; Malmbeck, R.; Rodrigues, A.; Glatz, J.-P.

    2017-08-01

    One of the concepts chosen for the transmutation of minor actinides in Accelerator Driven Systems or fast reactors proposes the use of fuels and targets containing minor actinides oxides embedded in an inert matrix either composed of molybdenum metal (CerMet fuel) or of ceramic magnesium oxide (CerCer fuel). Since the sufficient transmutation cannot be achieved in a single step, it requires multi-recycling of the fuel including recovery of the not transmuted minor actinides. In the present work, a pyrochemical process for treatment of Mo metal inert matrix based CerMet fuels is studied, particularly the electroreduction in molten chloride salt as a head-end step required prior the main separation process. At the initial stage, different inactive pellets simulating the fuel containing CeO2 as minor actinide surrogates were examined. The main studied parameters of the process efficiency were the porosity and composition of the pellets and the process parameters as current density and passed charge. The results indicated the feasibility of the process, gave insight into its limiting parameters and defined the parameters for the future experiment on minor actinide containing material.

  12. Effects of Sm doping content on the ionic conduction of CeO2 in SOFCs from first principles

    Science.gov (United States)

    Fu, Zhaoming; Sun, Qian; Ma, Dongwei; Zhang, Na; An, Yipeng; Yang, Zongxian

    2017-07-01

    Sm-doping effects on ionic conduction of the CeO2 electrolyte in solid oxide fuel cells (SOFCs) are investigated using the first-principles calculations. We focus on the influence of the Sm content on ionic conductivity in Sm-doped ceria (SDC). In previous studies, the Sm-doping effects are attributed to the increase in the oxygen vacancies induced by Sm3+. However, our investigations reveal that Sm doping contents play multiple roles in affecting the ionic conductivity. First, the activity of oxygen migration can be controlled by the Sm concentration. Second, the association energy between the dopant and oxygen vacancies, which is very important for O conductivity in SDC, can also be tuned by changing the dopant content. In addition, oxygen-rich and oxygen-poor conditions will significantly modify the band structures of SDC. Our work is helpful to understand the mechanism of high ionic conductivity in the electrolyte of Sm-doped ceria in SOFCs.

  13. Enhanced activity and stability of La-doped CeO2 monolithic catalysts for lean-oxygen methane combustion.

    Science.gov (United States)

    Zhu, Wenjun; Jin, Jianhui; Chen, Xiao; Li, Chuang; Wang, Tonghua; Tsang, Chi-Wing; Liang, Changhai

    2018-02-01

    Effective utilization of coal bed methane is very significant for energy utilization and environment protection. Catalytic combustion of methane is a promising way to eliminate trace amounts of oxygen in the coal bed methane and the key to this technology is the development of high-efficiency catalysts. Herein, we report a series of Ce 1-x La x O 2-δ (x = 0-0.8) monolithic catalysts for the catalytic combustion of methane, which are prepared by citric acid method. The structural characterization shows that the substitution of La enhance the oxygen vacancy concentration and reducibility of the supports and promote the migration of the surface oxygen, as a result improve the catalytic activity of CeO 2 . M-Ce 0.8 La 0.2 O 2-δ (monolithic catalyst, Ce 0.8 La 0.2 O 2-δ coated on cordierite honeycomb) exhibits outstanding activity for methane combustion, and the temperature for 10 and 90% methane conversion are 495 and 580 °C, respectively. Additionally, Ce 0.8 La 0.2 O 2-δ monolithic catalyst presents excellent stability at high temperature. These Ce 1-x La x O 2-δ monolithic materials with a small amount of La incorporation therefore show promises as highly efficient solid solution catalysts for lean-oxygen methane combustion. Graphical abstract ᅟ.

  14. Toxicity of inhaled 144CeO2 in immature, young adult and aged Syrian hamsters. II

    International Nuclear Information System (INIS)

    Hobbs, C.H.; McClellan, R.O.; Benjamin, S.A.

    1974-01-01

    Syrian hamsters have been exposed to aerosols of 144 CeO 2 at 28 (immature), 84 (young adult), and 340 (aged) days of age to better define the dose-response relationships following inhalation of this radionuclide by a population with a wide range of ages such as would be the case with a human population following a catastrophic nuclear accident. The animals were exposed to achieve graded initial lung burdens (ILB) for the younger exposure ages of about 20, 5, 1.25, 0.31, 0.80, and 0.01 μCi and control groups exposed to stable cerium oxide. The aged animals were exposed to achieve ILB of 20, 5, 1.25, and 0.31 μCi as well as a control group. Animals are being maintained both for serial sacrifice to determine the radiation dose pattern and for lifespan observation to determine dose-response relationships. The effective half-life of 144 Ce in the lung appears to be about 63 days. This would result in a dose to lung of about 4000 rads/μCi of ILB. Animals with ILB of about 20 μCi have died at early times with radiation pneumonitis and pulmonary fibrosis. No excessive mortality compared to that of controls has been observed in the remaining exposure levels. Histopathologic examination is not complete on all animals that have died, but no pulmonary neoplasms have been observed to date. (U.S.)

  15. Electrical Properties of a CeO2-Bi2O3 Mix System Elaborated at 600°C

    Directory of Open Access Journals (Sweden)

    Lamia Bourja

    2012-01-01

    Full Text Available The electrical conduction of a series of polycristalline [(1−xCeO2⋅x/2Bi2O3] samples has been analyzed using electrical impedance spectroscopy, in the temperature range 25 to 750∘C. Samples have been prepared via a coprecipitation route followed by a pyrolysis process at 600∘C. For compositions x≤0.20, Ce1−xBixO2−x/2 solid solutions, with fluorite cubic structure, are obtained. In the composition range 0.30≤x≤1, the system is biphasic with coexistence of cubic and tetragonal structures. To interpret the Nyquist representations of electrical analyses, various impedance models including constant phase elements and Warburg impedances have been used. In the biphasic range (0.30≤x≤0.7, the conductivity variation might be related to the increasing fraction of two tetragonal β′ and β-Bi2O3 phases. The stabilization of the tetragonal phase coexisting with substituted ceria close to composition x=0.7 is associated with a high conduction of the mix system CeO2-Bi2O3.

  16. Ordered misfit dislocations in epitaxial Gd doped CeO2 thin films deposited on (001)YSZ single crystal substrates

    Science.gov (United States)

    Petrișor, T.; Meledin, A.; Boulle, A.; Moș, R. B.; Gabor, M. S.; Ciontea, L.; Petrișor, T.

    2018-03-01

    Misfit dislocations are ubiquitous in thin film systems, and their presence can profoundly affect the chemical and physical properties of materials. In the present paper, we investigate the misfit dislocation array present at the interface of a Gd doped CeO2 thin film epitaxially grown on a (001) yttria stabilized zirconia (YSZ) single crystal substrate. Because of the large misfit strain (-4.9%), the growth takes place by domain-matching epitaxy with the formation of geometrical misfit dislocations. Transmission electron microscopy (TEM) observations, combined with geometrical phase analysis and strain field calculations (in the case of elastic isotropy), reveal that the misfit dislocations are of purely edge type with Burgers vector b = ½[110] and with the dislocations lines parallel to the [1-10] direction. X-ray diffraction, combined with Monte Carlo simulations, allow to quantify the statistical properties of the dislocations ensemble. It is found that the dislocations are distributed according to a Gamma distribution with a mean dislocation spacing of 7.4 nm and with a spacing ranging from 3.5 to 12 nm, in excellent agreement with TEM observations and with the values expected from the relaxation of the misfit strain.

  17. Synthesis of cerium oxide (CeO2) with high surface area through microwave assisted hydrothermal method

    International Nuclear Information System (INIS)

    Oliveira, M.J.C. de; Neiva, L.S.; Gama, L.; Oliveira, J.B.

    2011-01-01

    The objective of this research is synthesize nanoparticles with high surface area of Ceria (CeO 2 ) catalyst by a microwave hydrothermal method. For that it was used a 5% concentration in weight of [Ce(NO 3 ) 3. 6H 2 O] and 10 mL of [NaOH (5M)] under processing conditions in the equipment: maximum temperature of 150 deg C for 60 min with heating rate of 15 C /min. The resulting sample was characterized by XRD, SEM and BET method. It was observed that the Ceria particles are presented spatially in cubic structure, with crystallite size of 10 nm and surface area of 112 m²/g. Through the pore size distribution it was possible to observe that these were in mesoporous size, ranging from 3 to 30 nm. The possibility of obtaining catalysts with nanometer scale and high surface area by beans of microwave hydrothermal method, which involves low energy (low temperatures) and short synthesis time, makes this method very interesting and promising. (author)

  18. Photoluminescence and electrochemical properties of transparent CeO2-ZnO nanocomposite thin films prepared by Pechini method

    Science.gov (United States)

    Sani, Z. Khosousi; Ghodsi, F. E.; Mazloom, J.

    2017-02-01

    Nanocomposite thin films of CeO2-ZnO with different molar ratios of Zn/Ce (=0, 0.25, 0.5, 0.75 and 1) were prepared by the Pechini sol-gel route. Various spectroscopic and electrochemical techniques were applied to investigate the films. XRD patterns of all the samples exhibited the peaks corresponding to cubic fluorite structure of ceria and the (101) and (103) peaks of ZnO with hexagonal structure was just observed in the sample with molar ratio of 1. EDS confirmed the presence of constituent of element in the samples. FESEM images of the films showed a surface composed of nanograins. AFM analysis revealed that root mean square roughness was enhanced as molar ratio of Zn/Ce increased. Moreover, fractal dimension of surfaces were calculated by cube counting approach. Optical measurements indicated that the film with molar ratio of 1 has the highest transmission and lowest reflectivity. The optical band gap values varied between 2.95 and 3.42 eV. The compositional dependence of refractive index and extinction coefficient were reported. The UV and blue emission appeared in PL spectra. The highest photoluminescence emission intensity was observed in the 1:1 molar ratio sample. The cyclic voltammetry measurements indicated the highest charge density (9.75 mC cm-2) and diffusion coefficient (3.507 × 10-17 cm2 s-1) belonged to the Ce/Zn (1:1) thin film.

  19. ROS mediated malignancy cure performance of morphological, optical, and electrically tuned Sn doped CeO2 nanostructures

    Science.gov (United States)

    Abbas, Fazal; Iqbal, Javed; Maqbool, Qaisar; Jan, Tariq; Ullah, Muhammad Obaid; Nawaz, Bushra; Nazar, Mudassar; Naqvi, M. S. Hussain; Ahmad, Ishaq

    2017-09-01

    To grapple with cancer, implementation of differentially cytotoxic nanomedicines have gained prime attention of the researchers across the globe. Now, ceria (CeO2) at nanoscale has emerged as a cut out therapeutic agent for malignancy treatment. Keeping this in view, we have fabricated SnxCe1-xO2 nanostructures by facile, eco-friendly, and biocompatible hydrothermal method. Structural examinations via XRD and FT-IR spectroscopy have revealed single phase cubic-fluorite morphology while SEM analysis has depicted particle size ranging 30-50nm for pristine and doped nanostructures. UV-Vis spectroscopy investigation explored that Sn doping significantly tuned the band gap (eV) energies of SnxCe1-xO2 nanostructures which set up the base for tremendous cellular reactive oxygen species (ROS) generations involved in cancer cells' death. To observe cytotoxicity, synthesized nanostructures were found selectively more toxic to neuroblastoma cell lines as compared to HEK-293 healthy cells. This study anticipates that SnxCe1-xO2 nanostructures, in future, might be used as nanomedicine for safer cancer therapy.

  20. Empiricist Interventions

    DEFF Research Database (Denmark)

    Munk, Anders Kristian; Abrahamsson, Sebastian

    2012-01-01

    Recent papers by prominent scholars in science and technology studies (notably JohnLaw and Bruno Latour) have crystallized a fundamental disagreement about the scope and purpose of intervention in actor-network theory or what we here choose to bracket as empirical philosophy. While the precept...

  1. Cognitive training for children with ADHD: a randomized controlled trial of cogmed working memory training and 'paying attention in class'.

    Science.gov (United States)

    van der Donk, Marthe; Hiemstra-Beernink, Anne-Claire; Tjeenk-Kalff, Ariane; van der Leij, Aryan; Lindauer, Ramón

    2015-01-01

    The goal of this randomized controlled trial was to replicate and extend previous studies of Cogmed Working Memory Training (CWMT) in children with Attention-deficit/hyperactivity disorder (ADHD). While a large proportion of children with ADHD suffer from academic difficulties, only few previous efficacy studies have taken into account long term academic outcome measures. So far, results regarding academic outcome measures have been inconsistent. Hundred and two children with ADHD between the age of 8 and 12 years (both medicated and medication naïve) participated in current randomized controlled trial. Children were randomly assigned to CWMT or a new active combined working memory- and executive function compensatory training called 'Paying Attention in Class.' Primary outcome measures were neurocognitive functioning and academic performance. Secondary outcome measures contained ratings of behavior in class, behavior problems, and quality of life. Assessment took place before, directly after and 6 months after treatment. Results showed only one replicated treatment effect on visual spatial working memory in favor of CWMT. Effects of time were found for broad neurocognitive measures, supported by parent and teacher ratings. However, no treatment or time effects were found for the measures of academic performance, behavior in class or quality of life. We suggest that methodological and non-specific treatment factors should be taken into account when interpreting current findings. Future trials with well-blinded measures and a third 'no treatment' control group are needed before cognitive training can be supported as an evidence-based treatment of ADHD. Future research should put more effort into investigating why, how and for whom cognitive training is effective as this would also potentially lead to improved intervention- and study designs.

  2. Student Evaluation of Instruction: Comparison between In-Class and Online Methods

    Science.gov (United States)

    Capa-Aydin, Yesim

    2016-01-01

    This study compares student evaluations of instruction that were collected in-class with those gathered through an online survey. The two modes of administration were compared with respect to response rate, psychometric characteristics and mean ratings through different statistical analyses. Findings indicated that in-class evaluations produced a…

  3. Children's relative age in class and use of medication for ADHD: a Danish Nationwide Study

    DEFF Research Database (Denmark)

    Pottegård, Anton; Hallas, J.; Hernandez, Diaz

    2014-01-01

    estimated the prevalence proportion ratio (PPR) of receiving ADHD medication between the youngest children in class (born in October-December) and the oldest in class (born in January-March), specified by grade level, calendar year and gender. As a sensitivity analysis, we added children not on their age...

  4. Online Quizzes Promote Inconsistent Improvements on In-Class Test Performance in Introductory Anatomy and Physiology

    Science.gov (United States)

    Brown, Gregory A.; Bice, Matthew R.; Shaw, Brandon S.; Shaw, Ina

    2015-01-01

    Review quizzes can provide students with feedback and assist in the preparation for in-class tests, but students often do not voluntarily use self-testing resources. The purpose of the present study was to evaluate if taking a mandatory online review quiz alters performance on subsequent in-class tests. During two semesters of a single-semester…

  5. Interventional MRI

    Energy Technology Data Exchange (ETDEWEB)

    Fukatsu, Hiroshi [Nagoya Univ. (Japan). School of Medicine

    2002-01-01

    MR guided interventional procedures have become useful clinical tools recently. In this article the authors discuss the usefulness and problems of MR-guided needle biopsy and MR-guided laser induced thermotherapy (LITT) for clinical cases. MR enabled optimal plane monitoring with desired image contrast during the procedure without X-ray irradiation for puncture and tissue sampling. Also only MR could non-invasively provide interstitial temperature information during laser ablation. Bone and soft tissue lesions are likely to be candidates for MR interventions because they are free from any physiological motions, and radiologists should compare MR-guidance with CT- or US guidance for individual cases in order to achieve a less invasive diagnosis or treatment. (author)

  6. Spinal interventions.

    Science.gov (United States)

    Ruiz Santiago, F; Filippiadis, D K; Guzmán Álvarez, L; Martínez Martínez, A; Castellano, M M

    2016-04-01

    We review the state of the art in imaging-guided percutaneous interventional procedures used to diagnose and/or treat the diverse causes of back pain. These procedures can be used for diagnosis, treatment, or both. They are focused on the vertebral bodies, the facet joints, the intervertebral discs, and the nerve structures. Copyright © 2015 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

  7. A qualitative study of how to create supportive environments for the implementation of in-class-activities in middle school

    DEFF Research Database (Denmark)

    Holt, Anne-Didde; Smedegaard, Søren; Christiansen, Lars Breum Skov

    the intervention period, a case study comprising 10 semi-structured focus group interviews were carried out with 37 4th and 6th-grade students. Furthermore, the involved class teachers were interviewed. The interviews aimed to gain insight into students and teachers experiences with the implementation of ICA......Purpose School physical activity (SPA) holds the potential to benefit children’s psychosocial well-being. PA can positively influence mental health through social connectedness, physical self-perception, and improvements in emotions. For such reasons, in-class-activities (ICA) (e.g. energizers......, active breaks) has been given increased attention in the literature. However, if all students are to benefit from the potential mental health qualities of ICA, the right supportive environment is crucial. The purpose of this study was, on the basis of students and teachers feedback to an ICA...

  8. Pressure-induced phase transitions and correlation between structure and superconductivity in iron-based superconductor Ce(O(0.84)F(0.16))FeAs.

    Science.gov (United States)

    Zhao, Jinggeng; Liu, Haozhe; Ehm, Lars; Dong, Dawei; Chen, Zhiqiang; Liu, Qingqing; Hu, Wanzheng; Wang, Nanlin; Jin, Changqing

    2013-07-15

    High-pressure angle-dispersive X-ray diffraction experiments on iron-based superconductor Ce(O(0.84)F(0.16))FeAs were performed up to 54.9 GPa at room temperature. A tetragonal to tetragonal isostructural phase transition starts at about 13.9 GPa, and a new high-pressure phase has been found above 33.8 GPa. At pressures above 19.9 GPa, Ce(O(0.84)F(0.16))FeAs completely transforms to a high-pressure tetragonal phase, which remains in the same tetragonal structure with a larger a-axis and smaller c-axis than those of the low-pressure tetragonal phase. The structure analysis shows a discontinuity in the pressure dependences of the Fe-As and Ce-(O, F) bond distances, as well as the As-Fe-As and Ce-(O, F)-Ce bond angles in the transition region, which correlates with the change in T(c) of this compound upon compression. The isostructural phase transition in Ce(O(0.84)F(0.16))FeAs leads to a drastic drop in the superconducting transition temperature T(c) and restricts the superconductivity at low temperature. For the 1111-type iron-based superconductors, the structure evolution and following superconductivity changes under compression are related to the radius of lanthanide cations in the charge reservoir layer.

  9. One-pot synthesis of La0.7Sr0.3MnO3 supported on flower-like CeO2 as electrocatalyst for oxygen reduction reaction in aluminum-air batteries

    Science.gov (United States)

    Xue, Yejian; Huang, Heran; Miao, He; Sun, Shanshan; Wang, Qin; Li, Shihua; Liu, Zhaoping

    2017-08-01

    A novel La0.7Sr0.3MnO3-CeO2 (LSM-CeO2) hybrid catalyst for oxygen reduction reaction (ORR) has been synthesized by a facile one-pot method. The flower-like CeO2 with the diameter of about 3 μm is formed by the agglomeration of nanosheets with the thickness of about 40 nm. The LSM particles with the diameter of about 150 nm are well distributed on the flower-like CeO2, thus the interaction between LSM and CeO2 is built. Therefore, the LSM-CeO2 composite catalyst exhibits the much higher catalytic activity toward ORR with the direct four-electron transfer mechanism in alkaline solution than LSM or CeO2. Furthermore, the stability of LSM-CeO2 is superior to that of Pt/C, and the current retention is 93% after 100000 s. The maximum power density of the aluminum-air battery using LSM-CeO2 as the ORRC can reach 238 mW cm-2, which is about 29% higher than that with LSM (184 mW cm-2). It indicates that LSM-CeO2 composite material is a promising cathodic electrocatalyst for metal-air batteries.

  10. Carcinoma sebáceo palpebral: Presentación de un caso Palpeebral sebaceous carcinoma: A case report

    Directory of Open Access Journals (Sweden)

    María Cáceres Toledo

    1999-06-01

    Full Text Available Se presenta a un paciente de 26 años de edad, con diagnóstico clínico de chalación gigante del párpado inferior del ojo derecho de 6 meses de evolución, con un gran componente inflamatorio y bordes ulcerados que no había respondido a la terapéutica médica ni quirúrgica. El resultado de la biopsia tomada de este lesión fue, carcinoma epidermoide infiltrante, por lo que decidimos hacer la cirugía con margen oncológico, que requirió de un colgajo libre del párpado superior con fines estéticos y funcionales. El estudio histológico de la tumoración evidenció un carcinoma sebáceo. La evolución posoperatoria de este paciente, al año de operado, ha sido satisfactoriaA 26-year-old patient wich clinical diagnosis of giant chalazi on of the lower eyelid of the right eye with 6 months of evolution and with a great inflamatory component and ulcerated edges that had not responded to mechical and surgical therapeutics is presented. The result of the biopsy was infiltrating epidermoid carcinoma, so it was decided to perform surgery with oncological margin that required a free flap of the upper eyelid with aesthetic functional ends. The histological study of the tumor proved the existance of a sebaceous carcinoma. The posoperative evolution of the patient after a year has been satisfactory

  11. Kinetics of oxygen exchange over CeO2-ZrO2 fluorite-based catalysts.

    Science.gov (United States)

    Sadovskaya, Ekaterina M; Ivanova, Yulia A; Pinaeva, Larisa G; Grasso, Giacomo; Kuznetsova, Tatiana G; van Veen, Andre; Sadykov, Vladislav A; Mirodatos, Claude

    2007-05-24

    The kinetics of 18O/16O isotopic exchange over CeO2-ZrO2-La2O3 and Pt/CeO2-ZrO2 catalysts have been investigated under the conditions of dynamic adsorption-desorption equilibrium at atmospheric pressure and a temperature range of 650-850 degrees C. The rates of oxygen adsorption-desorption on Pt sites, support surface, oxygen transfer (spillover) from Pt to the support as well as the amount of oxygen accumulated in the oxide bulk, and oxygen diffusion coefficient were estimated. The nanocrystalline structure of lanthana-doped ceria-zirconia prepared via the Pechini route with a developed network of domain boundaries and specific defects guarantees a high oxygen mobility in the oxide bulk (D = (1.5 / 2.0).10-18 m2 s-1 at 650 degrees C) and allows accumulation of over-stoichiometric/excess oxygen. For Pt/CeO2-ZrO2, oxygen transfer from Pt to support (characteristic time surface. The rate of direct exchange between the gas phase and surface oxygen is increased as well due to the increased concentration (up to 2 monolayers) of surface/near subsurface oxygen species accumulated on the oxygen vacancies (originated from the incorporation of highly dispersed Pt atoms). The characteristic time of diffusion of the oxygen localized in the subsurface layers is about 1 s. The overall quantity of over-stoichiometric oxygen and/or hydroxyl groups accumulated in the bulk can reach the equivalent of 10 monolayers, and characteristic time of oxygen diffusion within the bulk is about 20 s. All these kinetic data are required for the further step of modeling partial oxidation of hydrocarbons under steady- and unsteady-state conditions.

  12. Synthesis and room-temperature ferromagnetism of CeO2 nanocrystals with nonmagnetic Ca2+ doping.

    Science.gov (United States)

    Chen, Xiaobo; Li, Guangshe; Su, Yiguo; Qiu, Xiaoqing; Li, Liping; Zou, Zhigang

    2009-03-18

    This work initiates an investigation on the creation of room-temperature ferromagnetism in diamagnetic solid via a nonmagnetic doping. CeO(2) is taken as a prototype compound. A series of Ce(1-x)Ca(x)O(2-delta) solid solutions with x = 0-0.25 were prepared by a solution combustion method using L-glutamic acid as the fuel. Sample characterization indicates that all as-prepared samples crystallized in a pure face-centered cubic fluorite structure with crystallite sizes smaller than 10 nm. On increasing the dopant content, the crystallite size decreased from about 8 to 4 nm, while the lattice parameter increased systematically. At room temperature, all samples are ferromagnetic admixed with an apparent diamagnetic component, as composed to a mixture of paramagnetic and antiferromagnetic behaviors or the absence of the ferromagnetism reported in the literature (Bouaine et al 2007 J. Phys. Chem. C 111 2924-8; Ney et al 2008 Phys. Rev. Lett. 100 157201) for magnetically doped semiconductors such as Sn(1-x)Co(x)O(2) and Zn(1-x)Co(x)O. The coercivity and saturation magnetization for x = 0 are 110 Oe and 2.01 x 10(-4) emu g(-1), respectively, which slightly increased to 148 Oe and 2.26 x 10(-4) emu g(-1) on increasing the dopant content to x = 0.10. Upon annealing the as-prepared samples at 800 degrees C for 2 h, these magnetic parameters were weakened. This observation was interpreted in terms of the mixed valence state of Ce(3+)/Ce(4+) and the doping effects. Finally, the nature of the room-temperature ferromagnetism is discussed by taking into account the oxygen vacancies and defects at the surface/interfaces that act as the electron and hole traps.

  13. Shubnikov-de Haas Oscillations of filled skutterudite compounds CeOs4Sb12andNdOs4Sb12

    Science.gov (United States)

    Ho, P.-C.; Singleton, J.; Balakirev, F. F.; Maple, M. B.; Yanagisawa, T.

    2015-03-01

    The filled skutterudite compounds CeOs4Sb12, PrOs4Sb12,andNdOs4Sb12 are respectively a 1 K antiferromagnetic (AFM) Kondo insulator, a 1.85 K unconventional superconductor (SC), and a 1 K mean-field type ferromagnet (FM). Since SC in PrOs4Sb12 exhibits non-BCS properties, it may originate from proximity to AFM and FM quantum-critical points. Therefore, Fermi-surface measurements of NdOs4Sb12andCeOs4Sb12 become crucial in understanding the SC pairing mechanism in PrOs4Sb12. MHz skin-depth measurements of single crystals of CeOs4Sb12andNdOs4Sb12 were performed for temperatures down to 1.3 K and magnetic fields of up to 60 tesla in the Pulsed Field Facility at NHMFL/LANL. Proximity detection oscillator (PDO) data are taken in the 60 tesla generator-driven magnet (~ 1 s) using a rotational probe. Shubnikov-de Haas oscillations were detected for various direction of the magnetic field with respect to the crystalline orientations. The results indicate that NdOs4Sb12 has similar Fermi surfaces to those of PrOs4Sb12andLaOs4Sb12 but that the Fermi surface of CeOs4Sb12 is much different from those of the other three compounds. Research at CSU-Fresno is supported by NSF DMR-1104544; at UCSD by NSF DMR-1206553 and US DOE DE-FG02-04ER46105; at at NHMFL by DOE, NSF, and FL; at Hokkaido U by MEXT, Jpn.

  14. REVISIÓN DE LA EVIDENCIA CIENTÍFICA SOBRE LAS ALTERNATIVAS A LA METADONA EN EL TRATAMIENTO PSICOFARMACOLÓGICO DE LA DEPENDENCIA A OPIÁCEOS

    Directory of Open Access Journals (Sweden)

    Álvaro Iruín

    2001-01-01

    Full Text Available Fundamento: El establecimiento de los programas de mantenimiento con metadona supuso un auténtico hito en el tratamiento de aquellos pacientes dependientes a opiáceos que habían fracasado con las diferentes alternativas terapéuticas existentes en su momento. En este trabajo se hace una revisión de la evidencia científica sobre las ventajas e inconvenientes de las diferentes alternativas farmacológicas de sustitución a la metadona en personas dependientes de opiáceos. Para identificar los ensayos clínicos realizados se llevaron a cabo búsquedas en Medline (1966-1999, el sistema IDIS (Iowa Drug Information System(1985-1999 y la base de datos de ensayos clínicos de la Cochrane Library 1999 (3er trimestre. Selección y síntesis de la literatura. De la revisión realizada se concluye que metadona es el fármaco de elección en el tratamiento sustitutivo de pacientes dependientes a opiáceos. LAAM aparece como una alternativa a la metadona en pacientes estables que no requieran un seguimiento estrecho, si bien desde marzo de 2001 ha sido suspendida la autorización de comercialización por recomendación del Comité Científico de la Agencia Europea de Evaluación de Medicamentos. Buprenorfina puede ser una alternativa a la metadona, pero todavía no se conoce su régimen óptimo de dosificación. La heroína es la alternativa menos estudiada; si bien, los escasos estudios existentes indican que podría ser una alternativa útil en heroinómanos en los que otros tratamientos de mantenimiento hayan fracasado.

  15. Caracterização de material compósito diatomáceo natural Characterization of natural diatomaceous composite material

    Directory of Open Access Journals (Sweden)

    G. P. Souza

    2003-03-01

    Full Text Available O presente trabalho mostra os resultados de um estudo sobre as características físico-químicas e morfológicas de uma amostra de material compósito diatomáceo obtida de uma lagoa de água doce (Campos dos Goytacazes-RJ. Este material foi selecionado de modo que suas características com respeito a morfologia, composição química, difração de raios X, análise térmica, análise de tamanho de partícula e superfície específica pudessem ser estudadas. Os resultados revelaram uma morfologia tubular para o material diatomáceo. Este material é constituído basicamente por sílica e caulinita, bem como apresenta um tamanho de frústula acima de 15 mim. Os resultados obtidos indicam que o material diatomáceo tem potencial para aproveitamento para beneficiamento.The present work focuses on the morphological and physical-chemical characteristics of a diatomaceous composite material sample obtained of a fresh-water pond. This material was selected so that its characteristics regarding morphology, chemical composition, X-ray diffraction, thermal analysis, particle size analysis and specific surface could be studied. It was found tubular morphology for the diatomaceous composite material. In addition, it is constituted basically by silica and kaolinite, as well as presents a diatomaceous earth size above 15 mum. The obtained results suggest also that the diatomaceous material has potentiality to be employed for processing.

  16. Interventional Oncology.

    Science.gov (United States)

    Culp, William T N

    2016-05-01

    The approach to the treatment of cancer in veterinary patients is constantly evolving. Whenever possible and practical, surgery is pursued because it provides the greatest opportunity for tumor control and may result in a cure. Other cancer treatments, such as chemotherapy and radiation therapy, are commonplace in veterinary medicine, and the data outlining treatment regimens are growing rapidly. An absence of treatment options for veterinary cancer patients, however, has historically existed for some tumors. Interventional oncology options have opened the door to the potential for better therapeutic response and improved patient quality of life. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Synthesis by sol-gel and characterization of catalysts Ag/Al2O3- CeO2 for the elimination of nitric oxide

    International Nuclear Information System (INIS)

    Zayas R, M.L.

    2005-01-01

    The environmental pollution is one from the big problems to solve at the present time, because the quality of the alive beings life is affected. For such reason, more clean and economic technologies are required, that it conduces to develop new catalytic alternatives to diminish the nitrogen oxides that due to its chemical processes in the environment contribute considerably in the air pollution. The main objective of the present work, is the preparation and characterization of catalytic materials with base of silver supported in simple and mixed aluminium oxides (Al 2 O 3 ) and Cerium oxide (CeO 2 ), and its catalytic evaluation that through of the reduction of nitric oxide (NO) using hydrogen (H 2 ) as reducer agent. It was synthesized alumina (Al 2 O 3 ) and Cerium oxide (CeO 2 ) and mixed oxides (Al 2 O 3 - CeO 2 ), by the sol-gel method and the cerium oxide (CeO 2 ) by precipitation of the cerium nitrate (III) hexa hydrated. The oxides were stabilized thermally at 900 C by 5 hr. The catalysts were prepared by impregnation using silver nitrate (AgNO 3 ), the nominal concentration of Ag was of 5% in weight. The catalysts were reduced at 400 C by 2 hr, in hydrogen flow of 60 cc/min. The characterization of the catalytic materials was carried out through different techniques as: nitrogen adsorption to determine the surface area BET, scanning electron microscopy (SEM) to observe the final morphology of the catalysts, X-ray diffraction (XRD) to identify the crystalline phases of the catalytic materials, Infrared spectroscopy (DRIFT) to know the structural characterization of the catalysts, reduction to programmed temperature (TPR) to evidence the interaction metal-support. The catalytic properties of the catalysts were evaluated in the model reaction NO + H 2 , to determine the activity and selectivity. The results indicate that the preparation technique, the precursors and the thermal treatments that underwent these materials influence in the catalyst and by

  18. Tratamiento con enjuagues de ketamina asociado o no a fentanilo transmucoso en el dolor oncológico orofacial resistente a opiáceos mayores

    OpenAIRE

    Cortiñas Saenz, Manuel; Espín Galvez, Fernando; Alférez García, Inmaculada; Menoyo Alonso, Miren Beatriz; Vega Salvador, Ana; García-Carricondo, Ana

    2015-01-01

    Objetivo: Evaluar la efectividad de los enjuagues de ketamina asociados o no a fentanilo transmucoso en una serie de diversos dolores orofaciales de etiología neoplásica de difícil control analgésico. Material y métodos: Estudio prospectivo de 20 pacientes, con 8 pacientes que recibieron enjuagues de ketamina (40 mg = 4 ml), 8 pacientes que recibieron ketamina asociada a citrato de fentanilo por vía transmucosa oral a dosis de 200 mcg y 4 pacientes con opiáceos sistémicos para el dolor oro...

  19. Total catalytic wet oxidation of phenol and its chlorinated derivates with MnO2/CeO2 catalyst in a slurry

    OpenAIRE

    Luna, A. J.; Rojas, L. O. A.; Melo, D. M. A.; Benachour, M.; Sousa, J. F. de

    2009-01-01

    In the present work, a synthetic effluent of phenol was treated by means of a total oxidation process-Catalyzed Wet Oxidation (CWO). A mixed oxide of Mn-Ce (7:3), the catalyst, was synthesized by co-precipitation from an aqueous solution of MnCl2 and CeCl3 in a basic medium. The mixed oxide, MnO2/CeO2, was characterized and used in the oxidation of phenol in a slurry reactor in the temperature range of 80-130ºC and pressure of 2.04-4.76 MPa. A phenol solution containing 2.4-dichlorophenol and...

  20. Ionic conductivity ageing behaviour of 10 mol.% Sc2O3–1 mol.% CeO2–ZrO2 ceramics

    DEFF Research Database (Denmark)

    Omar, Shobit; Bonanos, Nikolaos

    2010-01-01

    The long-term ionic conductivity behaviour of samples of zirconia co-doped with 10 mol.% of Sc2O3 and 1 mol.% CeO2 is evaluated in oxidizing and reducing atmospheres at 600 °C. After 3,000 h, the sample kept in reducing atmospheres exhibits 20% loss in the ionic conductivity, while the sample kept...... in air shows 6% degradation. No phase transitions were observed in the samples after both the ageing studies. The main contribution towards the loss in the ionic conductivity of the sample kept in air comes from grain boundaries; however, for the sample aged in reducing conditions, both grain and grain...

  1. Inmunopatogenia del pénfigo vulgar y el pénfigo foliáceo = Immunopathogenesis of pemphigus vulgaris and pemphigus foliaceus

    OpenAIRE

    Valencia Ocampo, Óscar Jairo; Velásquez Lopera, Margarita María

    2011-01-01

    El pénfigo vulgar y el pénfigo foliáceo son enfermedades ampollosas autoinmunes mediadas por autoanticuerpos dirigidos contra proteínas de los desmosomas, las desmogleínas 1 y 3. Están asociadas con moléculas del complejo mayor de histocompatibilidad (HLA) que por su estructura tienen la capacidad de presentar péptidos antigénicos de las desmogleínas. En los individuos afectados se han descrito la presencia de linfocitos T y B autorreactivos y alteraciones en la regulación del sistema inmune ...

  2. ETNOECOLOGIA DE PEQUENOS CETÁCEOS POR PESCADORES ARTESANAIS DO MUNICÍPIO DE MARABÁ, SUDESTE DO ESTADO DO PARÁ-BRASIL

    Directory of Open Access Journals (Sweden)

    Tiago Pereira Brito

    2016-09-01

    Full Text Available O pescador ao desenvolver a pesca passa a interagir cotidianamente com o ambiente, adquirindo um conhecimento ecológico sobre o meio, sua fauna e flora. Conhecimento esse fundamental para o manejo e a conservação dos estoques pesqueiros e espécies que de alguma forma interagem com a atividade. Diante disso, o presente estudo objetivou avaliar os aspectos etnoecológicos dos pescadores de Marabá, sudeste do estado do Pará, quanto a ocorrência de cetáceos na região e os tipos de interações desses com a pesca. Foram realizadas 50 entrevistas semi-estruturadas com os pescadores do município. A observação de cetáceos foi confirmada por todos os pescadores. O boto-tucuxi (Sotalia fluviatilis tem sido observado por 100,0% dos entrevistados, enquanto o boto-rosa (Inia geoffrensis, por 86,0%. Os animais podem ser avistados em pequenos grupos de dois a três indivíduos, no entanto, o tucuxi comumente tem sido observado em grupos de 10 e 40 animais ou com filhotes. Os tipos de interações desses cetáceos com a pesca foram: aproximação do boto ao pescador; aproximação do animal às embarcações; aproximação do animal ao petrecho pesqueiro; afugentamento dos cardumes; consumo dos peixes capturados; danos aos artefatos pesqueiros; e capturas acidentais. Todos os pescadores afirmam que os cetáceos prejudicam a atividade pesqueira. Oito entrevistados afirmam ter capturado acidentalmente botos em redes (arrasto e emalhe, os quais são soltos, não havendo registrado de consumo deles. O conhecimento a respeito das interações entre a pesca e esses animais pode contribuir para o aperfeiçoamento das artes pesqueiras, de modo a reduzir as capturas acidentais e otimizar o desenvolvimento da atividade, bem como contribuir para conservação desses animais na região. Palavras-chave: Conhecimento ecológico. Interação Operacional. Inia geoffrensis. Sotalia fluviatilis.

  3. CHx adsorption (x = 1-4) and thermodynamic stability on the CeO2(111) surface: A first-principles investigation

    KAUST Repository

    Fronzi, Marco

    2014-01-01

    We present an ab initio investigation of the interaction between methane, its dehydrogenated forms and the cerium oxide surface. In particular, the stoichiometric CeO2(111) surface and the one with oxygen vacancies are considered. We study the geometries, energetics and electronic structures of various configurations of these molecules adsorbed on the surface in vacuum, and we extend the analysis to realistic environmental conditions. A phase diagram of the adsorbate-surface system is constructed and relevant transition phases are analyzed in detail, showing the conditions where partial oxidation of methane can occur. © 2014 The Royal Society of Chemistry.

  4. Resistive switching effects in CeO2/La0.7(Sr0.1Ca0.9)0.3MnO3/Pt heterostructures prepared by pulse laser deposition method

    International Nuclear Information System (INIS)

    Chen, X.G.; Fu, J.B.; Li, L.Z.; Yun, C.; Zhao, H.; Zhang, X.F.; Wang, C.S.; Yang, Y.C.; Yang, J.B.

    2014-01-01

    The heterostructural junctions of CeO 2 /La 0.7 (Sr 0.1 Ca 0.9 ) 0.3 MnO 3 /Pt (CeO 2 /LSCMO/Pt) were prepared using pulse laser deposition technique. Their resistive switching (RS) behavior was investigated. As compared to the metal/manganite/Pt junction, the CeO 2 /LSCMO/Pt device displayed an improved switching characteristic. The RS effects with characteristics of bipolar, threshold, and complementary were realized by adjusting the thicknesses of the CeO 2 layer in the CeO 2 /LSCMO/Pt junctions. Under a higher external bias voltage, the threshold and complementary switching modes of the junctions could turn into bipolar switching mode. The switching behavior shows strong dependence on the O 2 partial pressure during the fabrication, indicating that the amount and behavior of the oxygen at the interface play an important role in the determination of the RS behavior. The observed switching behavior is related to the modification of the accumulation/depletion layers as well as the interfacial potential barrier due to the migration of the oxygen vacancies. - Highlights: • Heterostructure of CeO 2 /LSMO/Pt displayed an improved resistance switching characteristic. • Resistance switching with characteristics of bipolar, threshold and complementary was found. • Threshold and complementary switching mode could turn into bipolar switching mode. • Switching behavior is related to the modification of the accumulation/depletion layers. • Interfacial potential barrier due to the migration of oxygen vacancies was proposed

  5. Plasma-catalyst hybrid reactor with CeO2/γ-Al2O3 for benzene decomposition with synergetic effect and nano particle by-product reduction.

    Science.gov (United States)

    Mao, Lingai; Chen, Zhizong; Wu, Xinyue; Tang, Xiujuan; Yao, Shuiliang; Zhang, Xuming; Jiang, Boqiong; Han, Jingyi; Wu, Zuliang; Lu, Hao; Nozaki, Tomohiro

    2018-04-05

    A dielectric barrier discharge (DBD) catalyst hybrid reactor with CeO 2 /γ-Al 2 O 3 catalyst balls was investigated for benzene decomposition at atmospheric pressure and 30 °C. At an energy density of 37-40 J/L, benzene decomposition was as high as 92.5% when using the hybrid reactor with 5.0wt%CeO 2 /γ-Al 2 O 3 ; while it was 10%-20% when using a normal DBD reactor without a catalyst. Benzene decomposition using the hybrid reactor was almost the same as that using an O 3 catalyst reactor with the same CeO 2 /γ-Al 2 O 3 catalyst, indicating that O 3 plays a key role in the benzene decomposition. Fourier transform infrared spectroscopy analysis showed that O 3 adsorption on CeO 2 /γ-Al 2 O 3 promotes the production of adsorbed O 2 - and O 2 2‒ , which contribute benzene decomposition over heterogeneous catalysts. Nano particles as by-products (phenol and 1,4-benzoquinone) from benzene decomposition can be significantly reduced using the CeO 2 /γ-Al 2 O 3 catalyst. H 2 O inhibits benzene decomposition; however, it improves CO 2 selectivity. The deactivated CeO 2 /γ-Al 2 O 3 catalyst can be regenerated by performing discharges at 100 °C and 192-204 J/L. The decomposition mechanism of benzene over CeO 2 /γ-Al 2 O 3 catalyst was proposed. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Incidência do pênfigo vulgar ultrapassa a do pênfigo foliáceo em região endêmica para pênfigo foliáceo: análise de série histórica de 21 anos Incidence of pemphigus vulgaris exceeds that of pemphigus foliaceus in a region where pemphigus foliaceus is endemic: analysis of a 21-year historical series

    OpenAIRE

    Gilson Antonio Pereira Gonçalves; Moema Mignac Cumming Brito; Adriana Martinelli Salathiel; Thais Serraino Ferraz; Domingos Alves; Ana Maria Ferreira Roselino

    2011-01-01

    FUNDAMENTO: Há dois tipos principais de pênfigo: pênfigo vulgar e pênfigo foliáceo. Nos últimos anos, mudanças clínicas e epidemiológicas relacionadas aos pênfigos têm sido observadas. OBJETIVOS: Teve-se por objetivo analisar uma série histórica de 21 anos de casos de pênfigo vulgar e pênfigo foliáceo no nordeste do estado de São Paulo, área endêmica para o pênfigo foliáceo. MÉTODOS: Neste estudo descritivo, foram analisados os dados relacionados à incidência anual e à idade de início do quad...

  7. Cambios de CEO y presidentes de directorio en el Perú : un enfoque para las empresas peruanas con mayor frecuencia de negociación en la BVL de 1992 al 2014

    OpenAIRE

    Asencios Flores, Ilich Ivan; Caballero Del Pino, César; Valencia Martínez, Miguel Angel

    2016-01-01

    Esta investigación tiene como objetivo determinar si los anuncios de cambios de CEO y presidentes de Directorio de las empresas listadas en la Bolsa de Valores de Lima (BVL) afectan el valor de la firma en los días cercanos al anuncio. Fue la pronta salida de Steve Jobs como CEO de Apple Inc., a causa de una enfermedad mortal, lo que nos generó el cuestionamiento respecto a cuál sería el desempeño que tienen las acciones cuyas compañías pasan por eventos similares. Como se sabe, el mercado...

  8. College Can Fire Teacher for Swearing at Student in Class, U.S. Court Rules.

    Science.gov (United States)

    Mangan, Katherine S.

    1987-01-01

    An appellate court found that a college faculty member's use of offensive language in class was unprofessional, interfered with instruction, and not protected by principles of free speech and academic freedom. (MSE)

  9. Representation of Power in Class Discourse: A Study of Communication Ethnography

    Directory of Open Access Journals (Sweden)

    Jumadi Jumadi

    2016-02-01

    Full Text Available This study is aimed at describing the use of power in class discourse covering representation of power in speech act, representation of power in communication patterns and function of power in class discourse. Communication ethnography and pragmatic methods were used. The research results show that the use of directive, assertive, and expressive acts in class discourse represent the power with certain domination; that the control of speech topics, interruptions, and overlapping tend to represent the power with certain domination that also effect the legitimacy of the user of this strategy. In relation to its function, power in class discourse is applied as a preventive, supportive, and corrective acts in order to achieve instructional objective.

  10. PRODUÇÃO DE QUITOSANA A PARTIR DA QUITINA EXTRAÍDA DE RESÍDUOS DE CRUSTÁCEOS

    Directory of Open Access Journals (Sweden)

    Caroline de Souza Fontes

    2017-02-01

    Full Text Available A atividade pesqueira brasileira gera um PIB de R$ 5 bilhõese mobiliza 800 mil profissionais. Em função desta atividade econômica, o descarte de resíduos de crustáceos sem nenhum tratamento tem se tornado um problema ambiental, uma proposta para minimiza-lo é a utilização destes resíduos para a obtenção de matéria prima de interesse industrial. Sendo assim, foi avaliado o efeito da concentração do NaOH no processo de obtenção da quitosana. Com base na utilização de materiais comuns de laboratório, a obtenção da quitosana foi realizada a partir da algumas etapas, como a desacetilação da quitina. Esta proposta demonstrou-se eficiente uma vez que o aumento no teor de NaOH promoveu um aumento no rendimento na produção da quitosana. Acredita-se que este trabalho venha a contribuir com a redução de resíduos de crustáceos, visto que o interesse industrial pela quitosana vem aumentando devido as suas propriedades bacteriostáticas, fungistática e cicatrizantes.

  11. Thermoluminescence induced by UV radiation in ZrO2-La2O3 and ZrO2-CeO2 mixed systems

    International Nuclear Information System (INIS)

    Estrada G, R.; Salas C, P.; Mendoza A, D.; Gonzalez, P.R.

    2002-01-01

    Nowadays, the development of catalytic materials by means of pure or mixed oxides mainly as TiO 2 , Al 2 O 3 , ZrO 2 , La 2 O 3 and CeO 2 used as support or active phases, are widely used in oxidation-reduction reactions in the chemical industry and in petroleum refining processes. the cerium and lanthanum oxides in zircon, have been studied recently in processes for reduction of pollutant gases (SO x , NO x , etc.). They result very interesting for resolving the problems of environmental pollution. Moreover, it has been observed that some of these materials are highly sensitive to ultraviolet radiation (UV), characteristic that can be took in advantage for detecting this type of radiation. In this work the preliminary obtained results on the thermoluminescent response (Tl) induced by the UV radiation in ZrO 2 -La 2 O 3 and ZrO 2 -CeO 2 mixed systems obtained by the sol-gel method are presented. The results show that the first system has a high sensitivity to UV radiation with a Tl curve composed by three peaks, two ones of greater intensity located in 70 and 140 Centigrade degrees. Likewise it was observed that for both materials, the peak located at low temperature is fadeout in few minutes after irradiation, while that the second one peak presented very good stability, resulting promising for dosimetric applications in UV radiation fields. (Author)

  12. COLONIZACIÓN DE MOLUSCOS Y CRUSTÁCEOS EN RAÍCES DE MANGLE ROJO EN UNA LAGUNA COSTERA DE LA PUNTA NORTE DEL GOLFO DE MORROSQUILLO

    Directory of Open Access Journals (Sweden)

    PRÜSMANN JOHANNA

    2010-05-01

    Full Text Available Se evaluaron la colonización y sucesión de moluscos y crustáceos en un sustrato de raíces de mangle en tres estaciones en la ciénaga La Boquilla, Punta San Bernardo en la parte norte del Golfo de Morrosquillo. Para el seguimiento del proceso de colonización se ubicaron tres sitios en las márgenes occidental, norte y oriental, y se fijaron en cada estación seis raíces aéreas deshojadas de Rhizophora mangle. Luego de 76 y 200 días de exposición, se retiraron tres raíces de cada sitio y se identificaron los organismos por morfoespecie. Después de 200 días de exposición, se determinaron 19 especies de moluscos y cinco de crustáceos. El anfípodo Corophium sp. y el bivalvo Brachidontes exustus fueron las especies mas numerosas y agruparon una fracción muy importante de la totalidad de los individuos recolectados. La mayoría de las especies encontradas son típicas de la fauna acompañante de las raíces de mangle en el Caribe colombiano.

  13. Synthesis and physicochemical characterizations of nanostructured Pt/Al2O3-CeO2 catalysts for total oxidation of VOCs.

    Science.gov (United States)

    Abbasi, Zahra; Haghighi, Mohammad; Fatehifar, Esmaeil; Saedy, Saeed

    2011-02-28

    Pt/Al(2)O(3)-CeO(2) nanocatalysts with Pt loading of 1% and ceria loading of 10, 20 and 30% were successfully prepared via wet impregnation method to be utilized in catalytic oxidation of BTX. The nanocatalysts were characterized using XRD, FESEM, TEM, N(2) adsorption, FTIR and TPR-H(2) techniques. The XRD patterns confirmed the formation of cerium oxide as the crystalline phase on alumina with the average crystallite size of 8.1-8.7 nm, derived by Scherrer equation. FESEM images confirmed that these nanocatalysts had ceria particles in nano-ranges. TEM analysis showed that platinum particles were fairly well dispersed on Al(2)O(3)-CeO(2) with an average size of 5-20 nm. BET surface area presented large surface area for nanocatalysts. TPR patterns showed that by adding 1% platinum to support, the reducibility is highly increased. These patterns also revealed the promoting effect of ceria on reducibility of Pt and Al(2)O(3). The results of toluene oxidation indicated that the synthesized nanocatalysts were highly active and able to remove nearly 100% of toluene and xylene and about 85% of benzene as representative VOCs. The presence of nanoparticles along with good characteristics of the synthesized nanocatalysts presented them as highly efficient materials for catalytic oxidation of VOCs. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. Probing the interaction of Rh, Co and bimetallic Rh-Co nanoparticles with the CeO2 support: catalytic materials for alternative energy generation.

    Science.gov (United States)

    Varga, E; Pusztai, P; Óvári, L; Oszkó, A; Erdőhelyi, A; Papp, C; Steinrück, H-P; Kónya, Z; Kiss, J

    2015-10-28

    The interaction of CeO2-supported Rh, Co and bimetallic Rh-Co nanoparticles, which are active catalysts in hydrogen production via steam reforming of ethanol, a process related to renewable energy generation, was studied by X-ray diffraction (XRD), high resolution electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and low energy ion scattering (LEIS). Furthermore, diffuse reflectance infrared spectroscopy (DRIFTS) of adsorbed CO as a probe molecule was used to characterize the morphology of metal particles. At small loadings (0.1%), Rh is in a much dispersed state on ceria, while at higher contents (1-5%), Rh forms 2-8 nm particles. Between 473-673 K pronounced oxygen transfer from ceria to Rh is observed and at 773 K significant agglomeration of Rh occurs. On reduced ceria, XPS indicates a possible electron transfer from Rh to ceria. The formation of smaller ceria crystallites upon loading with Co was concluded from XRD and HRTEM; for 10% Co, the CeO2 particle size decreased from 27.6 to 10.7 nm. A strong dissolution of Co into ceria and a certain extent of encapsulation by ceria were deduced by XRD, XPS and LEIS. In the bimetallic system, the presence of Rh enhances the reduction of cobalt and ceria. During thermal treatments, reoxidation of Co occurs, and Rh agglomeration as well as oxygen migration from ceria to Rh are hindered in the presence of cobalt.

  15. Aspectos dermatoscópicos do siringocistoadenoma papilífero associado a nevo sebáceo Dermoscopic aspects of syringocystadenoma papilliferum associated with nevus sebaceus

    Directory of Open Access Journals (Sweden)

    Carolina Barbosa Bruno

    2011-12-01

    Full Text Available O siringocistoadenoma papilífero é uma neoplasia anexial benigna rara, com frequente diferenciação apócrina. Localiza-se preferencialmente no couro cabeludo e está associado ao nevo sebáceo em 40% dos casos. Apesar da variabilidade clínica, a histologia é característica. Há relatos da dermatoscopia de tumores anexiais, como poroma écrino, hidradenoma e angio-histiocitoma; porém, até o momento, não há descrição da dermatoscopia do siringocistoadenoma. Apresentamos aspectos dermatoscópicos de um caso de siringocistoadenoma associado a nevo sebáceo, visualizando-se padrão vascular polimorfo e vasos em ferradura.Syringocystadenoma papilliferum is a rare benign adnexal tumor that frequently shows apocrine differentiation. It usually develops on the scalp and is associated with a nevus sebaceus in 40% of cases. Although the clinical presentation may differ, its histology is characteristic. Reports have been made of dermoscopy used in cases of adnexal tumors such as eccrine poromas, hidradenomas and angiohistiocytomas; however, up to the present moment there have been no reports of dermoscopy in a case of syringocystadenoma. This paper describes the dermoscopic features found in a case of syringocystadenoma associated with a nevus sebaceus, revealing a polymorphous vascular pattern including a horseshoe-shaped arrangement of vessels.

  16. Tuning the hybridization and magnetic ground state of electron and hole doped CeOs2Al10 : An x-ray spectroscopy study

    Science.gov (United States)

    Chen, Kai; Sundermann, Martin; Strigari, Fabio; Kawabata, Jo; Takabatake, Toshiro; Tanaka, Arata; Bencok, Peter; Choueikani, Fadi; Severing, Andrea

    2018-04-01

    Here we present linear and circular polarized soft x-ray absorption spectroscopy (XAS) data at the Ce M4 ,5 edges of the electron (Ir) and hole-doped (Re) Kondo semiconductor CeOs2Al10 . Both substitutions have a strong impact on the unusual high Néel temperature TN=28.5 K, and also the direction of the ordered moment in case of Ir. The substitution dependence of the linear dichroism is weak thus validating the crystal-field description of CeOs2Al10 being representative for the Re and Ir substituted compounds. The impact of electron and hole doping on the hybridization between conduction and 4 f electrons is related to the amount of f0 in the ground state and reduction of x-ray magnetic circular dichroism. A relationship of c f -hybridization strength and enhanced TN is discussed. The direction and doping dependence of the circular dichroism strongly supports the idea of strong Kondo screening along the crystallographic a direction.

  17. EXAFS analysis of the L3 edge of Ce in CeO2: effects of multielectron excitations and final-state mixed valence

    International Nuclear Information System (INIS)

    Fonda, E.; Andreatta, D.; Colavita, P.E.; Vlaic, G.

    1999-01-01

    Cerium oxide (IV) (CeO 2 ) is extensively employed in heterogeneous catalysis, particularly as a promoter of noble metal action in three-way catalysts. For this reason there is a great scientific and economical interest in the development of any possible chemical or structural analysis technique that could provide information on these systems. EXAFS spectroscopy has revealed itself as a powerful technique for structural characterization of such catalysts. Unfortunately, good quality K-edge spectra of cerium are not yet easily obtainable because of the high photon energy required (>40 keV). On the other hand, at lower energies it is easy to collect very good spectra of the L 3 edge (5.5 keV), but L 3 -edge spectra of cerium (IV) are characterized by the presence of two undesired additional phenomena that interfere with EXAFS analysis: final-state mixed-valence behaviour and intense multi-electron excitations. Here, a comparative analysis of the K, L 3 , L 2 and L 1 edges of Ce in CeO 2 has been made and a procedure for obtaining structural parameters from L 3 -edge EXAFS, even in the presence of these features, has been developed. This procedure could allow further studies of catalytic compounds containing tetravalent cerium surrounded by oxygen ligands. (au)

  18. Ensamble de crustáceos bentónicos en un lago salino tropical Benthic crustaceans assemblage in a tropical, saline lake

    Directory of Open Access Journals (Sweden)

    Ma. del Carmen Hernández

    2010-10-01

    Full Text Available El presente trabajo reconoce la composición, estructura y distribución espacial del ensamble de crustáceos bentónicos de Alchichica, un lago salino tropical ubicado en el extremo oriental del altiplano mexicano. El lago presenta una riqueza taxonómica de crustáceos bentónicos compuesta por 1 anfípodo (Hyalella azteca, 1 isópodo (Caecidotea williamsi y 2 ostrácodos (Limnocythere inopinata y Candona sp.. Comparada con otros lagos tropicales, la riqueza de especies es reducida. A pesar de lo anterior, es importante mencionar el grado elevado de endemismo representado por C. williamsi, recientemente descrita para el lago Alchichica; adicionalmente, es factible que tanto Candona como H. azteca sean especies nuevas y endémicas del lago. Los crustáceos bentónicos se distribuyen desde la zona litoral hasta la zona más profunda del lago (62 m con abundancias y riqueza taxonómica variables. Los ostrácodos fueron los crustáceos que con mayor frecuencia se recolectaron en el lago, en la zona litoral, en el talud, y en la zona profunda de la que son habitantes exclusivos. Los anfípodos constituyeron el segundo grupo en abundancia de la zona litoral y talud y estuvieron ausentes en la zona profunda. Los isópodos sólo se encuentran asociados a los depósitos de tufa, hábitat característico del lago que se extiende a lo largo del talud, por lo que con las técnicas de muestreo tradicional empleadas en el presente estudio no fueron capturados. En este ensamble de crustáceos predominan las especies de desarrollo directo y con posiciones tróficas que incluyen componentes herbívoros (H. azteca, omnívoros (C. williamsi y bacterívoros (L. inopinata y Candona sp..This work acknowledges the composition, structure and spatial distribution of the benthic crustaceans assemblage of Alchichica, a tropical saline lake located in the easternmost portion of the Mexican highlands. The benthic crustaceans' assemblage was comprised by 1 amphipod

  19. Using In-class Group Exercises to Enhance Lectures and Provide Introductory Physics Students an Opportunity to Perfect Problem Solving Skills through Interactions with Fellow Students

    Science.gov (United States)

    Trout, Joseph; Bland, Jared

    2013-03-01

    In this pilot project, one hour of lecture time was replaced with one hour of in-class assignments, which groups of students collaborated on. These in-class assignments consisted of problems or projects selected for the calculus-based introductory physics students The first problem was at a level of difficulty that the majority of the students could complete with a small to moderate amount of difficulty. Each successive problem was increasingly more difficult, the last problem being having a level of difficulty that was beyond the capabilities of the majority of the students and required some instructor intervention. The students were free to choose their own groups. Students were encouraged to interact and help each other understand. The success of the in-class exercises were measured using pre-tests and post-tests. The pre-test and post-test were completed by each student independently. Statistics were also compiled on each student's attendance record and the amount of time spent reading and studying, as reported by the student. Statistics were also completed on the student responses when asked if they had sufficient time to complete the pre-test and post-test and if they would have completed the test with the correct answers if they had more time. The pre-tests and post-tests were not used in the computation of the grades of the students.

  20. AIP appoints New CEO

    Science.gov (United States)

    The American Institute of Physics (AIP) has announced the appointment of a new chief executive officer, Kenneth W. Ford, who is to succeed H. William Koch when Koch retires on March 28, 1987. Koch has held the position since 1966.AIP is a not-for-profit scientific organization made up of 10 member societies, including AGU, that represent more than 90,000 scientists. Its main activities include scientific publishing and marketing of 76 primary physics journals, including translations of foreign journals, books, conference proceedings, and the magazine Physics Today. AIP also is involved with electronic abstracting and other scientific communications and has active programs in education, public information, manpower statistics, and the history of physics.

  1. Hvis Thorning var CEO

    DEFF Research Database (Denmark)

    Boje Rasmussen, Martin Møller

    2013-01-01

    Helle Thorning-Schmidt er som statsminister blevet konfronteret med de samme syv overraskelser, som ifølge strategi- og ledelsesguruen Michael Porter udfordrer enhver nyudnævnt topleder. Regeringens fortsatte overlevelse afhænger af, hvor hurtigt statsministeren erkender det og handler....

  2. CeO2/rGO/Pt sandwich nanostructure: rGO-enhanced electron transmission between metal oxide and metal nanoparticles for anodic methanol oxidation of direct methanol fuel cells.

    Science.gov (United States)

    Yu, Xue; Kuai, Long; Geng, Baoyou

    2012-09-21

    Pt-based nanocomposites have been of great research interest. In this paper, we design an efficient MO/rGO/Pt sandwich nanostructure as an anodic electrocatalyst for DMFCs with combination of the merits of rigid structure of metallic oxides (MOs) and excellent electronic conductivity of reduced oxidized graphene (rGO) as well as overcoming their shortcomings. In this case, the CeO(2)/rGO/Pt sandwich nanostructure is successfully fabricated through a facile hydrothermal approach in the presence of graphene oxide and CeO(2) nanoparticles. This structure has a unique building architecture where rGO wraps up the CeO(2) nanoparticles and Pt nanoparticles are homogeneously dispersed on the surface of rGO. This novel structure endows this material with great electrocatalytic performance in methanol oxidation: it reduces the overpotential of methanol oxidation significantly and its electrocatalytic activity and stability are much enhanced compared with Pt/rGO, CeO(2)/Pt and Pt/C catalysts. This work supplies a unique MO/rGO/Pt sandwich nanostructure as an efficient way to improve the electrocatalytic performance, which will surely shed some light on the exploration of some novel structures of electrocatalyst for DMFCs.

  3. Liquid-Phase Ethanol Oxidation and Gas-Phase CO Oxidation Reactions over M Doped (M = Ag, Au, Pd, and Ni and MM′ Codoped CeO2 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Yohan Park

    2016-01-01

    Full Text Available Transition metal doped metal oxides have been studied extensively for potential applications to environments and chemical industry. Herein, M doped (M = Ag, Au, Pd, and Ni and MM′ codoped CeO2 nanoparticles (NPs were prepared by a hydrothermal method and their liquid-phase ethanol and gas-phase CO oxidation performances were examined by UV-visible absorption spectroscopy and temperature programmed mass spectrometry, respectively. The ethanol and CO oxidation performances were enhanced greatly by metal-doping and were dependent on the relative concentration of codoped metals. For ethanol oxidation, the concentration of acetaldehyde became saturated at low levels, while that of ethyl acetate continuously increased to become a final major product. For M doped CeO2 NPs, the ethanol oxidation performance showed an order of Ni < Ag < Pd ≪ Au. For MM′ codoped CeO2 NPs, the activity of Au doped CeO2 deteriorated drastically upon adding other metals (Ag, Ni, and Pd as a cocatalyst.

  4. Effect of CeO2 and Y2O3 on microstructure, bioactivity and degradability of laser cladding CaO-SiO2 coating on titanium alloy.

    Science.gov (United States)

    Li, H C; Wang, D G; Chen, C Z; Weng, F

    2015-03-01

    To solve the lack of strength of bulk biomaterials for load-bearing applications and improve the bioactivity of titanium alloy (Ti-6Al-4V), CaO-SiO2 coatings on titanium alloy were fabricated by laser cladding technique. The effect of CeO2 and Y2O3 on microstructure and properties of laser cladding coating was analyzed. The cross-section microstructure of ceramic layer from top to bottom gradually changes from cellular-dendrite structure to compact cellular crystal. The addition of CeO2 or Y2O3 refines the microstructure of the ceramic layer in the upper and middle regions. The refining effect on the grain is related to the kinds of additives and their content. The coating is mainly composed of CaTiO3, CaO, α-Ca2(SiO4), SiO2 and TiO2. Y2O3 inhibits the formation of CaO. After soaking in simulated body fluid (SBF), the calcium phosphate layer is formed on the coating surface, indicating the coating has bioactivity. After soaking in Tris-HCl solution, the samples doped with CeO2 or Y2O3 present a lower weight loss, indicating the addition of CeO2 or Y2O3 improves the degradability of laser cladding sample. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Aortoiliac interventions

    International Nuclear Information System (INIS)

    Chatziioannou, A.

    2012-01-01

    Full text: Atheromatosis is a systemic disease that involves various vascular beds. The most known risk factors are smoking, diabetes mellitus, dyslipedemia, hypertension, advanced age, black gender and male sex. Occlusive aortoiliac disease is due to atheromatosis in the vast majority of cases and is a common distribution of that pathology. Historically aortoiliac occlusions were treated with surgery. Nowadays, the endovascular minimally invasive techniques have revolutionized the treatment of such lesions. The success rate is extremely high with a technical success of 96%. Long term (5 years) patency of the diseased vessel can be as high as 71%. These results combined to the advent of new materials and techniques have set the new standards for treating aortoiliac occlusive disease. The first TASC recommendations (TASC I) were recently revised (TASC II) and the new guidelines (TASC III) will be shortly published. On the other hand endovascular techniques are not always successful. Technical failure (inability to cross the lesion) is estimated to be approximately 5% in single short iliac occlusions and can rise up to 15- 20% in complex long or multiple occlusive lesions. Possible, although not very frequent, complications are dissection, rupture and distal embolization. In the case of total occlusions we can use different materials and techniques. For example in an acute or subacute total occlusion chemical (urokinase or rtPA), mechanical or aspiration thrombolysis can be implemented. These minimally invasive techniques are of the outmost importance if we consider that the majority of the patients are old with a high rate of cardiac and other co-morbidities and therefore cannot go into surgery. That is the reason why the risk of morbidity and mortality following open surgical intervention remains high (5 - 20%). In chronic lesions we can use rentry catheters, glidewires, laser or thrombolysis/thrombectomy (if the clot is not very 'old'). Nevertheless, it should

  6. Facile biological synthetic strategy to morphologically aligned CeO2/ZrO2core nanoparticles using Justicia adhatoda extract and ionic liquid: Enhancement of its bio-medical properties.

    Science.gov (United States)

    Pandiyan, Nithya; Murugesan, Balaji; Sonamuthu, Jegatheeswaran; Samayanan, Selvam; Mahalingam, Sundrarajan

    2018-01-01

    In this study, a typical green synthesis route has approached for CeO 2 /ZrO 2 core metal oxide nanoparticles using ionic liquid mediated Justicia adhatoda extract. This synthesis method is carried out at simple room temperature condition to obtain the core metal oxide nanoparticles. XRD, SEM and TEM studies employed to study the crystalline and surface morphological properties under nucleation, growth, and aggregation processes. CeO 2 /ZrO 2 core metal oxides display agglomerated nano stick-like structure with 20-45nm size. GC-MS spectroscopy confirms the presence of vasicinone and N,N-Dimethylglycine present in the plant extract, which are capable of converting the corresponding metal ion precursor to CeO 2 /ZrO 2 core metal oxide nanoparticles. In FTIR, the corresponding stretching for Ce-O and Zr-O bands indicated at 498 and 416cm -1 and Raman spectroscopy also supports typical stretching frequencies at 463 and 160cm -1 . Band gap energy of the CeO 2 /ZrO 2 core metal oxide is 3.37eV calculated from UV- DRS spectroscopy. The anti-bacterial studies performed against a set of bacterial strains the result showed that core metal oxide nanoparticles more susceptible to gram-positive (G+) bacteria than gram-negative (G-) bacteria. A unique feature of the antioxidant behaviors core metal oxides reduces the concentration of DPPH radical up to 89%. The CeO 2 /ZrO 2 core metal oxide nanoparticles control the S. marcescent bio-film formation and restrict the quorum sensing. The toxicology behavior of CeO 2 /ZrO 2 core metal oxide NPs is found due to the high oxygen site vacancies, ROS formation, smallest particle size and higher surface area. This type of green synthesis route may efficient and the core metal oxide nanoparticles will possess a good bio-medical agent in future. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Carga parasitaria en crustáceos decápodos de la costa central de Chile: ¿existe alguna asociación con la abundancia de los hospedadores definitivos?

    Directory of Open Access Journals (Sweden)

    Natalia Leiva

    2015-09-01

    Full Text Available Los crustáceos tienen un rol importante en el ciclo de vida de los parásitos, ya que actúan como hospedadores intermediarios. No obstante, en Chile y a nivel mundial existen pocos estudios parasitológicos sobre crustáceos que habitan el intermareal rocoso. En este estudio se registró y comparó la carga parasitaria de crustáceos decápodos, y se relacionó con la abundancia de sus hospedadores definitivos (peces y aves. Entre julio y septiembre de 2013 se recolectaron 409 crustáceos, correspondientes a 16 especies, desde el intermareal rocoso de dos localidades de Chile central (33°S, Las Cruces y Montemar. El 65,5% de la muestra estaba parasitada, recolectándose 2.410 metacercarias y 18 nemátodos. Algunas metacercarias correspondían a la familia Opecoelidae, mientras que otras a Microphallidae; los nematodos eran de la familia Cystidicolidae. La mayor prevalencia y abundancia de Microphallidae se registró en Petrolisthes tuberculosus (42,3%; 4,8 ± 11,08 parásitos/crustáceo y de Opecoelidae en P. violaceus (96,9%; 13,59 ± 17,50 parásitos/crustáceo, mientras que Cystidicolidae fue poco prevalente y abundante en ambas localidades. Las infecciones parasíticas fueron afectadas por la localidad de muestreo, especie y tamaño del hospedador. No se encontró asociación entre la abundancia de los hospedadores definitivos y las cargas parasitarias que presentaban los crustáceos. La nula relación entre las cargas parasitarias y la abundancia de hospedadores definitivos puede ocurrir si estos últimos tienen un amplio espectro trófico o viajan largas distancias, de este modo, la transmisión de los parásitos no sería afectada directamente por la abundancia de los hospedadores definitivos.

  8. Etnoecologia de pequenos cetáceos: interações entre a pesca artesanal e golfinhos no norte do estado do Rio de Janeiro, Brasil

    Directory of Open Access Journals (Sweden)

    Gabrielle Amorim Rosa

    2012-04-01

    Full Text Available http://dx.doi.org/10.5007/2175-7925.2012v25n3p293   Estudos no norte do Rio de Janeiro indicam interações entre a pesca artesanal e os cetáceos, mas não existem pesquisas que abordem o conhecimento de pescadores sobre estes animais. O objetivo deste estudo é descrever as interações entre os cetáceos e a pesca através da percepção dos pescadores de Atafona (RJ. Entre fevereiro e março de 2010 foram selecionados 20 pescadores através da técnica “bola-de-neve” e aplicado um questionário etnográfico a fim de obter dados através de relatos da percepção cultural sobre os pequenos cetáceos no norte fluminense. Cada pescador descreveu mais de um golfinho, o que explica o tamanho amostral das respostas (N=34 maior que o número de entrevistados (N=20. Pelos relatos dos informantes foram identificadas três espécies e um gênero: Sotalia guianensis (N=15; 75%; Pontoporia blainvillei (N=9; 45%; Steno bredanensis (N=6; 30% e Stenella spp. (N=4; 20%. A resposta “colisão com artefatos” (rede de espera foi a única descrita na questão da ocorrência de acidentes entre a pesca e os golfinhos (N=24; 71% e a rede de espera é o artefato responsável pelo emalhe dos animais. As carcaças dos golfinhos emalhados podem ser descartadas ao mar e/ou a musculatura e gordura utilizadas como isca na pescaria de elasmobrânquios. As quatro principais espécies reportadas na literatura para a área foram as identificadas pelos pescadores. Para todos os entrevistados o emalhe é causado pelos golfinhos o que prejudica a pesca.

  9. Ultrasonic, FTIR and thermal investigations of SiO2-Na2O-CaO-P2O5 glasses doped with CeO2

    Science.gov (United States)

    Marzouk, Samir Y.

    2010-11-01

    The longitudinal and shear ultrasonic wave velocities for different compositions of SiO2-Na2O-CaO-P2O5 glasses were measured at room temperature (305 K) using a pulse-echo method at a frequency of 4 MHz. The elastic moduli, Poisson's ratio, microhardness, Debye temperature and other ultrasonic parameters were obtained from experimental data and analyzed using bond compression theory. By calculating the number of network bonds per unit volume, the average stretching constant, and the average ring size, information about the structure of the glass can be deduced. Structural changes after doping with CeO2 were investigated by FTIR spectroscopy, and by measurements of the thermal expansion coefficient, glass transition and softening temperature to throw more light on the characterization of these glasses.

  10. Characterization and Catalytic Activity for the Oxidation of Ethane and Propane on Platinum and Copper Supported on CeO2/Al2O3

    Directory of Open Access Journals (Sweden)

    Cataluña R.

    1998-01-01

    Full Text Available Ethane and propane oxidation on platinum and copper supported on Al2O3 and CeO2/Al2O3 catalysts were studied comparatively by examining reaction rates as a function of temperature. Results show that the addition of cerium oxide shifts the catalytic activity to higher temperatures. This negative influence is less pronounced in the case of supported copper samples, which on the basis of EPR and FTIR of adsorbed CO results is attributed to the low relative amount of this metal is in contact with ceria. The decrease in activity the presence of ceria might be due to changes in metal particle size or to the stabilization of the oxidized states of the metals, induced by their interactions with cerium oxide. The higher activity of platinum, in comparison with copper, is attributed to its higher reducibility along with an easier hydrocarbon activation on that metal.

  11. Preparations and characterizations of γ-Ce2S3 red pigments from Pr-doped CeO2 with improved thermal stabilities

    Science.gov (United States)

    Gao, Y. Q.; Li, Y. M.; Wang, Z. M.; Shen, Z. Y.; Xie, Z. X.

    2018-02-01

    The Pr-doped γ-Ce2S3 red pigment was prepared by a hydrothermal combine sulfurize process. CeCl3·7H2O, Pr6O11, and CS2 were used as cerium source, dopant source, and sulfur source, respectively. Pr-doped CeO2 precursor was prepared at 180 °C with hydrothermal method, followed by sulfurize treatment 150 min at 900 °C. The effect of doped proportion, sulfurize condition to phase composition of red pigment was observed. Furthermore, the thermal stabilities and chromaticity of as-prepared pigment were investigated. Results of calcinations in the air and color measure indicated that Pr-doping enhances the resistant temperature for oxidization of pigment. A red color ( L* = 25.58, a* = 29.47, b* = 17.27) was still remained after heated at 470 °C in the air.

  12. Successive Interfacial Reaction-Directed Synthesis of CeO2@Au@CeO2-MnO2 Environmental Catalyst with Sandwich Hollow Structure.

    Science.gov (United States)

    Chen, Guozhu; Wang, Yong; Wei, Yunwei; Zhao, Wei; Gao, Daowei; Yang, Hongxiao; Li, Cuncheng

    2018-04-11

    Noble metal nanoparticle-based catalysts are widely used for the removal of hazardous materials. During the catalytic reactions, it is of particular importance for developing novel strategies to avoid the leaching or sintering of noble metal nanoparticles. Here, the 4-nitrophenol (4-NP) and CO, typical hazardous chemicals in industrial water and exhaust gases from vehicles, are studied for their removal using CeO 2 @Au@CeO 2 -MnO 2 catalyst. The sandwich hollow structure is achieved by means of successive interfacial redox reaction without any surfactants and without involving any surface modifications. Because of the synergistic interaction between Au nanoparticles and oxides, the as-prepared environmental catalyst exhibits remarkable activity toward the 4-NP reduction. Moreover, the sandwich structure inhibits the growth of the Au nanoparticles and the as-prepared catalyst still displays high activity toward CO oxidation even when the catalyst is treated at 600 °C.

  13. A versatile CeO2/Co3O4coated mesh for food wastewater treatment: Simultaneous oil removal and UV catalysis of food additives.

    Science.gov (United States)

    Liu, Ya'nan; Liu, Na; Chen, Yuning; Zhang, Weifeng; Qu, Ruixiang; Zhang, Qingdong; Tzungyu-Shih; Feng, Lin; Wei, Yen

    2018-03-09

    Food waste water is one of the most urgent environmental problems for the close connection between food and our daily life. Herein, we use a simple hydrothermal method to prepare a highly efficient catalyst-CeO 2 /Co 3 O 4 compound on the stainless steel mesh, aiming for food waste water treatment. Possessing the superhydrophilic property and catalytic ability under ultraviolet light, CeO 2 /Co 3 O 4 coated mesh has successfully processed three representative contaminants in food wastewater, which are soybean oil (food oil), AR (food dye) and VA (food flavor) simultaneously with an one-step filtration. Besides, the mesh is stable in a wide pH range and performs well in reusability. Therefore, such a multifunctional material with simple preparation method, high processing efficiency and facile operation shows a promising prospect for practical production and application for food wastewater treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Synthesis and characterization of the TiO2-DOPED (CeO2)0,8(GdO1,5)0,2

    Energy Technology Data Exchange (ETDEWEB)

    Silva, R.I.V.; Domingues, S.; Santos, D.I.; Saeki, M.J. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sao Paulo, SP (Brazil); Cavalheiro, A.A. [Universidade Estadual do Mato Grosso do Sul (UEMS), Campo Grande, MS (Brazil)

    2009-07-01

    Full text: Among several types, the Solid Oxide Fuel Cell (SOFC) shows the higher efficiency for the energy conversion. The doped CeO2 have attracted much attention as an alternative material for anodic support due to its high ionic and electronic conduction. Titanium oxide (TiO2) is added to improve this property as well as it is used as a catalyst support for the selective oxidation reactions. This work aims to investigate TiO2 effect on the structure of cerium/gadolinium oxide, [(CeO2)0,8(GdO1,5)0,2]1-y(TiO2)y, where 0

  15. Synthesis and characterization of CeO2 - TiO2 system for use in heterogeneous photocatalysis in photodegradation of methylene blue dye

    International Nuclear Information System (INIS)

    Bragatto, Julia

    2016-01-01

    This study has as its goal the synthesis of a mixed oxide system type CeO 2 - TiO 2 , through the polymeric precursor method, to be used in heterogeneous photocatalysis. The synthesized materials were characterized by Thermogravimetry (TG), Derivative Thermogravimetry (DTG), Differential Thermal Analysis (DTA) and X-Ray Diffraction (XRD). The results of the thermal analysis showed in what temperature ranges certain events occur such as the formation of cerium oxide between 600 and 800 ° C, which refers to the crystallization of the material. Regarding the formation of titanium oxide, events between 600 and 800 ° C are perceived, which suggests the transformation of anatase to rutile phase. The XRD analysis showed no occurrence of the same phase for all materials, meaning that there is a variation in the formation of phases according to concentration of precursor for each sample. Noteworthy are the formation of CeO 2 for Ce75-Ti25 and Ce50-Ti50 concentrations, with cubic crystal structure of the fluorite type. In Ce75-Ti25 and Ce25-Ti75 it is present the TiO 2 in the anatase and rutile phase, with crystal structure of the tetragonal and tetrahedron type, respectively, as well as the formation of CeTi 2 O 6 in Ce50-Ti50 and Ce25-Ti75, with structure monoclinic. From these analyses, it is possible to see which samples, and in which temperatures of calcination the material has increased crystallinity, making the choice for their application in heterogeneous photocatalysis, aiming the degradation of methylene blue dye. Among the tested materials for methylene blue, the sample that stood out was the Ce50-Ti50, with calcination temperature of 800 °C, with values close to 50% degradation, because it was the sample that showed higher dye adsorption capacity, which is the step that precedes photodegradation. (author)

  16. Bioatividade de três espécies vegetais nativas da Floresta Atlântica brasileira frente ao microcrustáceo Artemia salina

    Directory of Open Access Journals (Sweden)

    W.M Pompilho

    2014-09-01

    Full Text Available Este trabalho teve por objetivo a investigação fitoquímica e propriedades antioxidantes de extratos das folhas de Trigynaea oblongifolia Schltdl (Annonaceae, Ottonia frutescens Trel (Piperaceae, e Bathysa australis (St Hill Hooz (Rubiaceae, bem como avaliar, in vitro, a letalidade frente ao microcrustáceo Artemia salina Leach. Os extratos foram preparados por maceração em metanol 10% (p/v por sete dias, à temperatura ambiente. A atividade antioxidante dos extratos foi determinada pela metodologia que utiliza o radical estável DPPH. A toxicidade dos extratos foi avaliada frente ao microcrustáceo A. salina. Os extratos de O. frutescens e B. australis apresentaram as seguintes classes de metabólitos secundários: Alcalóides, Antraquinonas, Cumarinas, Polifenóis (Taninos, Saponinas. Nos extratos de T. oblongifolia, além dos metabólitos citados anteriormente, foi detectada a presença de Flavonóides. A atividade antioxidante, observada em 30 minutos na concentração de 24 µg/mL de extrato, foi de: O. frutescens - 38,3%, T. oblongifolia - 32,3%, e B. australis - 32,1%. A Concentração Letal, CL50, dos extratos em A. salina foi de: O. frutescens - 149,75 ± 1,02 µg/mL, T. oblongifolia - 148,8 ± 1,74 µg/mL, e B. australis - 684 ± 9,04 µg/mL. Neste contexto, destacamos as espécies, nativas da Floresta Atlântica, O. frutescens e T. oblongifolia de grande potencial na bioprospecção de moléculas biologicamente ativas.

  17. The Magnetic Sentences Industry Game: A Competitive In-Class Experience of Business-Level Strategy

    Science.gov (United States)

    Casile, Maureen; Wheeler, Jane V.

    2005-01-01

    The Magnetic Sentences Industry Game is a high-energy in-class exercise designed to help students gain hands-on experience with setting, implementing, evaluating, and revising business-level strategy. Students compete in teams to create and market sentences using Magnetic Poetry (a product of Magnetic Poetry, Inc.). Revenues earned are highly…

  18. An Examination of In-Class Physical Activity across Games Classifications

    Science.gov (United States)

    Perlman, Dana J.; Forrest, Greg

    2015-01-01

    The purpose of this study was to examine the in-class physical activity opportunities across game classifications. A total of 221 (male, 100; female, 121) Year 9/10 physical education students were used within this study. Each student was engaged in four sport-based units (target, net/wall, striking/fielding, and invasion). Physical activity data…

  19. The Effects and Predictor Value of In-Class Texting Behavior on Final Course Grades

    Science.gov (United States)

    McDonald, Sylvia E.

    2013-01-01

    Cell phones have become a norm within the collegiate environment but little research has examined their impact on academic attainment. The purpose of this study was to examine the effects that in-class texting behavior had on the final grade score in a freshmen level introductory social science course. Students in three different sections were…

  20. Maxillary first molar extraction in Class II malocclusion : Follow-up studies on treatment effects

    NARCIS (Netherlands)

    Livas, Christos

    2015-01-01

    This PhD research investigated treatment effects of extraction of one and two maxillary first molars in Class II subdivision and Class II/1 malocclusion cases respectively from a longer time perspective. Private practice records were scrutinized to evaluate aspects of a treatment technique combining

  1. The role of charge transfer in the oxidation state change of Ce atoms in the TM13-CeO2(111) systems (TM = Pd, Ag, Pt, Au): a DFT + U investigation.

    Science.gov (United States)

    Tereshchuk, Polina; Freire, Rafael L H; Ungureanu, Crina G; Seminovski, Yohanna; Kiejna, Adam; Da Silva, Juarez L F

    2015-05-28

    Despite extensive studies of transition metal (TM) clusters supported on ceria (CeO2), fundamental issues such as the role of the TM atoms in the change in the oxidation state of Ce atoms are still not well understood. In this work, we report a theoretical investigation based on static and ab initio molecular dynamics density functional theory calculations of the interaction of 13-atom TM clusters (TM = Pd, Ag, Pt, Au) with the unreduced CeO2(111) surface represented by a large surface unit cell and employing Hubbard corrections for the strong on-site Coulomb correlation in the Ce f-electrons. We found that the TM13 clusters form pyramidal-like structures on CeO2(111) in the lowest energy configurations with the following stacking sequence, TM/TM4/TM8/CeO2(111), while TM13 adopts two-dimensional structures at high energy structures. TM13 induces a change in the oxidation state of few Ce atoms (3 of 16) located in the topmost Ce layer from Ce(IV) (itinerant Ce f-states) to Ce(III) (localized Ce f-states). There is a charge flow from the TM atoms to the CeO2(111) surface, which can be explained by the electronegativity difference between the TM (Pd, Ag, Pt, Au) and O atoms, however, the charge is not uniformly distributed on the topmost O layer due to the pressure induced by the TM13 clusters on the underlying O ions, which yields a decrease in the ionic charge of the O ions located below the cluster and an increase in the remaining O ions. Due to the charge flow mainly from the TM8-layer to the topmost O-layer, the charge cannot flow from the Ce(IV) atoms to the O atoms with the same magnitude as in the clean CeO2(111) surface. Consequently, the effective cationic charge decreases mainly for the Ce atoms that have a bond with the O atoms not located below the cluster, and hence, those Ce atoms change their oxidation state from IV to III. This increases the size of the Ce(III) compared with the Ce(IV) cations, which builds-in a strain within the topmost Ce layer, and

  2. Pulsed laser deposition of {CeO_2} and {Ce_{1-x}M_xO_2} (M = La, Zr): Application to insulating barrier in cuprate heterostructures

    Science.gov (United States)

    Berger, S.; Contour, J.-P.; Drouet, M.; Durand, O.; Khodan, A.; Michel, D.; Régi, F.-X.

    1998-03-01

    SrTiO_3 had been often tentatively used as an insulating barrier for HT superconductor/insulator heterostructures. Unfortunately, the deposition of SrTiO_3 on the YBa_2Cu_3O_7 inverse interface results in a poor epitaxial regrowth producing a high roughness dislocated titanate layer. Taking into account the good matching with YBa_2Cu_3O_7 and LaAlO_3, CeO_2 and Ce_{1-x}M_xO_2 (M = La, Zr), epitaxial layers were grown by pulsed laser deposition on LaAlO_3 substrates and introduced into YBa_2Cu_3O_7 based heterostructures as insulating barrier. After adjusting the growth parameters from RHEED oscillations, epitaxial growth is achieved, the oxide crystal axes being rotated by 45^circ from those of the substrate. The surface roughness of 250 nm thick films is very low with a rms value lower than 0.5 nm over 1;μ m^2. The YBa_2Cu_3O_7 layers of a YBa_2Cu_3O_7/CeO_2 /YBa_2Cu_3O_7 heterostructures grown using these optimized parameters show an independent resistive transition, when the thickness is larger than 25 nm, respectively at T_c_1 = 89.6;K and T_c_2 = 91.4;{K}. SrTiO3 est souvent utilisé comme barrière isolante dans des hétérostructures SIS de cuprates supraconducteurs, cependant les défauts générés lors de la croissance de ce titanate sur l'interface inverse de YBa2Cu3O7 conduisent à un matériau dont la qualité cristalline et les propriétés physiques sont médiocres. L'oxyde de cérium CeO2 est également une barrière isolante potentielle intéressante pour ces structures SIS basées sur YBa2Cu3O7 car cet oxyde cubique (a = 0,5411 nm, asqrt{2}/2 = 0,3825 nm) qui est peu désaccordé par rapport au plan ab du cuprate (Δ a/a = - 0,18 %, Δ b/a = 1,6 %) présente de plus un coefficient de dilatation thermique (10,6 × 10^{-6 circ}C^{-1}) très voisin de celui de YBa2Cu3O7 (13 × 10^{-6 circ}C^{-1}). Nous avons donc étudié l'épitaxie de CeO2 et des oxydes de type Ce{1-x}MxO2 (M = La, Zr) en ablation laser pulsée afin de définir des conditions de

  3. Desempeño de dos diseños de muestreo empleados en la evaluación de crustáceos demersales mediante el método de área barrida

    OpenAIRE

    Canales,Cristian; Arana,Patricio

    2009-01-01

    Se simula la densidad teórica de la variable Captura por Unidad de Área (CPUA) que podría tener un crustáceo demersal distribuido sobre la plataforma continental en una locación geográfica pre-defmida. Sobre esta densidad se simulan dos diseños de muestreo empleados tradicionalmente para la evaluación de crustáceos en Chile mediante el método de área barrida. Se evalúa el desempeño de un muestreo sistemático y otro aleatorio estratificado, considerando distintos escenarios en el número de est...

  4. Posible impacto en la salud pública del encallamiento de cetáceos en Costa Rica Potential public health impact of the stranding of cetaceans

    Directory of Open Access Journals (Sweden)

    Olga Rivas-Solano

    2013-06-01

    Full Text Available El encallamiento de cetáceos se presenta cuando estos mamíferos llegan a la playa sin poder regresar al mar por sus propios medios. En Costa Rica, la mayoría de los casos se han registrado en las costas del Pacífico. Entre las posibles causas de este fenómeno, están las enfermedades infecciosas como la brucelosis marina. Dicha enfermedad es provocada por bacterias del género Brucella, y se puede transmitir a los humanos. El contacto entre humanos y cetáceos ha venido en aumento debido a actividades recreativas y ocupacionales. Además, el varamiento usualmente llama la atención de turistas y locales, quienes tienden mantener un acercamiento estrecho con el animal encallado para tratar de regresarlo al mar. Lo anterior potencia el riesgo de transmisión de cepas patogénicas desde los mamíferos marinos hacia los humanos y otros animales. En Costa Rica se desarrolló, durante los años 2009 y 2011, un proyecto de investigación en cual participaron expertos de universidades estatales, de instituciones gubernamentales y de la Fundación Keto. Como parte del mismo, se organizaron talleres de capacitación a profesionales en salud, líderes comunales y autoridades locales de la costa pacífica, con el fin de concientizarlos sobre los protocolos a seguir para la atención integral de la problemática de los encallamientos de cetáceos, con miras a prevenir posibles situaciones de riesgo a la salud pública.Cetacean stranding occurs when those animals arrive to the beach without having the possibility to come back to the sea. In Costa Rica, most of the cases have been registered along the pacific coast.  Between the possible causes of the stranding, there are infectious diseases like marine brucellosis. This disease is caused by bacteria from the genus Brucella and it can be transmitted to humans. Contact between humans and cetaceans, has been increased because of touristic and working activities. Besides, stranding phenomenon usually calls

  5. Self-efficacy as a mediator of children's achievement motivation and in-class physical activity.

    Science.gov (United States)

    Gao, Zan; Lochbaum, Marc; Podlog, Leslie

    2011-12-01

    The present study was designed to examine the mediating effect of self-efficacy on relations of middle school students' four achievement goals with their perceptions of two motivational climates and in-class physical activity in physical education. The four achievement goals (mastery-approach, mastery-avoidance, performance-approach, and performance-avoidance), perceptions of the motivational climate (mastery- and performance-involving climates), and self-efficacy were measured in a sample of 194 students (93 boys, 101 girls) in a public school. Students' in-class physical activity was assessed using Actical Accelerometers. A series of multiple-regression analyses supported the mediating effect of self-efficacy on the relationships among students' mastery-approach goal, perceived mastery-involving climate, and physical activity.

  6. Dedication for Safety-Related Fuses used in Class-1E Power System

    International Nuclear Information System (INIS)

    Hong, Younghee

    2014-01-01

    The safety-related fuses used in class-1E power system provide overcurrent protection for electrical system and isolate the class 1E circuit from a fault or overload condition. These days, the number of nuclear grade suppliers has been reduced. Accordingly, commercial grade, instead of safety-related, fuses are procured and used in the utilities through the dedication process. Therefore, this paper introduces the commercial grade fuse dedication process/engineering and how to assure the quality requirements with this process and engineering. The fuses used in class-1E power system are to protect overcurrent and to isolate fault. Therefore the fuse for acceptance in order to improve the quality and reliability for commercial grade fuses shall be dedicated. The fuse resistance value may be useful as an indicator of acceptance. The current carrying capacity test can change the fuse performance properties. Therefore these critical characteristics are needed for additional review and analysis with fuse manufactures

  7. Oxygen Transfer on Substituted ZrO2, Bi2O3, and CeO2 Electrolytes with Platinum Electrodes. I. Electrode Resistance by D-C Polarization

    NARCIS (Netherlands)

    Verkerk, M.J.; Hammink, W.J.; Burggraaf, A.J.

    1983-01-01

    The electrode behavior of Pt-sputtered and PT-gauze electrodes on ZrO2-Y2O3, Bi2O3-Er2O3, and CeO2-Gd2O3 solid electrolyteswas investigated by means of d-c measurements in the temperature region of 770–1050 K and in the oxygen partialpressure region of 10–5 – 1 atm O2 using N2-O2 mixtures. On these

  8. "BiC in Sustainability?" : die Transparenz von Best in Class-Nachhaltigkeitsfonds in Deutschland

    OpenAIRE

    Schäfer, Henry; Bauer, Fabian; Bracht, Felix

    2015-01-01

    Der vorliegende Beitrag analysiert in Deutschland vertriebene Publikumsinvestmentfonds, die den Anspruch als Nachhaltigkeitsfonds erheben und nach dem Best in Class-Ansatz (BiC-Ansatz) in Kombination mit einem Negative-Screening (verstanden als Ausschlusskriterien) konstruiert sind. Ziel ist es zu erheben, auf welche Weise die den Fonds vom Anbieter zugrunde gelegten BiC- und Screening-Methoden Anlegern transparent gemacht werden und worin zwischen den Fonds diesbezüglich Unterschiede bestehe...

  9. Moluscos; anélidos y crustáceos asociados a las raíces de Rhizophora mangle linnaeus, en la región de Santa Marta, caribe colombiano Moluscos; anélidos y crustáceos asociados a las raíces de Rhizophora mangle Linnaeus, en la región de Santa Marta, caribe colombiano

    Directory of Open Access Journals (Sweden)

    Reyes Rosalba

    1992-09-01

    Full Text Available A qualitative and quantitative study of the community of macro invertebrates associated to the submerged stilt roots of the red mangrove, Rhizophora mangle Linnaeus, 1753, was carried out trimonthly between December 1988 and September 1989, in three stations at the Cienaga Grande de Santa Marta (CGSM and three at the Parque Nacional Natural Tayrona (PNNT, Bahia de Chengue, Bahia de Nenguange, Colombian Caribbean. 181 species were determined: 99 crustaceans, 50 molluscs and 32 annellids. Most of the 26.729 individuals counted were crustaceans (12.213 moluscs (11.635 and annellids (2.881. The lowest diversity and evenness values, and the highest dominance values were found at the CGSM, while the opposite occurred at the PNNT. Moreover, cluster analysis showed that at the CGSM temporal variations in community composition were greater than spatial ones, while at the PNNT spatial differences were stronger. Other factors that could be importantin determinig community structure were detected, such as vecinity to other ecosystems and/or species- specific biological aspects as adaptations to fluctuating conditions, reproductive acti vities, feeding habits and migration to protected and shaded habitats. Se realizó un estudio trimestral cualitativo y cuantitativo de la comunidad de moluscos, anélidos y crustáceos asociados a las raíces sumergidas del mangle rojo, Rhizophora mangle Linnaeus, entre diciembre de 1988 y septiembre de 1989, en tres estaciones en la Ciénaga Grande de Santa Marta (CGSM y tres en el Parque Nacional Natural Tayrona (PNNT, Bahía de Chengue y Bahía de Nenguange, Caribe colombiano. Se determinaron 181 especies: 99 crustáceos, 50 moluscos y 32 anélidos. En total se contaron 26.729 individuos: 12.213 crustáceos, 11.635 moluscos y 2.881 anélidos. Los valores más bajos de diversidad y equitatividad, y los mayores valores de dominancia, se encontraron en la CGSM, mientras que lo opuesto ocurrió en el PNNT. El análisis de

  10. Comparative study of palatal rugae pattern in class II div 1 and class I individuals

    Directory of Open Access Journals (Sweden)

    Chandrasekhar Gandikota

    2012-01-01

    Full Text Available Aims: To determine if the palatal rugae have a characteristic pattern in untreated class II div 1 malocclusions compared to normal class I occlusions, and to provide a valuable insight whether palatal rugae can be taken up as additional criteria for classifying malocclusions. Materials and Methods: The study was conducted on initial maxillary dental casts of 24 individuals with untreated class II div 1 malocclusion with an overjet of minimum of 5mm, of whom 12 were females and 12 were males, with age ranging from 16 to 24 years and compared with Class I patients casts. Results: There was no statistically significant difference in the mean intermolar widths of the two groups. The first, second and third palatal rugae were shorter in class II div 1 patients than in class I patients which was statistically significant. All the patients with Angle′s class I occlusion had good pattern of palatal rugae falling in the score range of 1-3, whereas 22% of the patients with class II div 1 had poor pattern of palatal rugae, with score 4 and 2 patients exhibiting a score of 4 and 5, respectively, but this was not statistically significant. Conclusion: There was a significant constriction of the palatal rugae in class II div 1 individuals as compared to class I individuals, though they were matched for the same intermolar widths. There was a distinct pattern of palatal rugae between the two groups.

  11. Comparative study of palatal rugae pattern in class II div 1 and class I individuals.

    Science.gov (United States)

    Gandikota, Chandrasekhar; Venkata, Yudhister Palla; Challa, Padmalatha; Juvvadi, Shubhaker Rao; Mathur, Anirudh

    2012-08-01

    To determine if the palatal rugae have a characteristic pattern in untreated class II div 1 malocclusions compared to normal class I occlusions, and to provide a valuable insight whether palatal rugae can be taken up as additional criteria for classifying malocclusions. The study was conducted on initial maxillary dental casts of 24 individuals with untreated class II div 1 malocclusion with an overjet of minimum of 5mm, of whom 12 were females and 12 were males, with age ranging from 16 to 24 years and compared with Class I patients casts. There was no statistically significant difference in the mean intermolar widths of the two groups. The first, second and third palatal rugae were shorter in class II div 1 patients than in class I patients which was statistically significant. All the patients with Angle's class I occlusion had good pattern of palatal rugae falling in the score range of 1-3, whereas 22% of the patients with class II div 1 had poor pattern of palatal rugae, with score 4 and 2 patients exhibiting a score of 4 and 5, respectively, but this was not statistically significant. There was a significant constriction of the palatal rugae in class II div 1 individuals as compared to class I individuals, though they were matched for the same intermolar widths. There was a distinct pattern of palatal rugae between the two groups.

  12. Effect of Ce doping of TiO2 support on NH3-SCR activity over V2O5-WO3/CeO2-TiO2 catalyst.

    Science.gov (United States)

    Cheng, Kai; Liu, Jian; Zhang, Tao; Li, Jianmei; Zhao, Zhen; Wei, Yuechang; Jiang, Guiyuan; Duan, Aijun

    2014-10-01

    CeO2-TiO2 composite supports with different Ce/Ti molar ratios were prepared by a homogeneous precipitation method, and V2O5-WO3/CeO2-TiO2 catalysts for the selective catalytic reduction (SCR) of NOx with NH3 were prepared by an incipient-wetness impregnation method. These catalysts were characterized by means of BET, XRD, UV-Vis, Raman and XPS techniques. The results showed that the catalytic activity of V2O5-WO3/TiO2 was greatly enhanced by Ce doping (molar ratio of Ce/Ti=1/10) in the TiO2 support. The catalysts that were predominantly anatase TiO2 showed better catalytic performance than the catalysts that were predominantly fluorite CeO2. The Ce additive could enhance the surface adsorbed oxygen and accelerate the SCR reaction. The effects of O2 concentration, ratio of NH3/NO, space velocity and SO2 on the catalytic activity were also investigated. The presence of oxygen played an important role in NO reduction. The optimal ratio of NH3/NO was 1/1 and the catalyst had good resistance to SO2 poisoning. Copyright © 2014. Published by Elsevier B.V.

  13. Peers and Academic Achievement: A Longitudinal Study on Selection and Socialization Effects of In-Class Friends

    Science.gov (United States)

    Fortuin, Janna; van Geel, Mitch; Vedder, Paul

    2016-01-01

    The present study was conducted to analyze whether in-class friends influence each other's grades, and whether adolescents tend to select friends that are similar to them in terms of academic achievement. During 1 academic year, 542 eighth-grade students (M age = 13.3 years) reported on 3 different occasions on their in-class friendship networks.…

  14. Interventional Radiology: Stroke

    Science.gov (United States)

    ... Government affairs Global outreach Publications Annual Report IR Quarterly Journal of Vascular and Interventional Radiology Newsletters Practice Resources Quality Improvement Clinical practice MACRA Matters Health Policy, Economics, Coding Toolkits Society of Interventional Radiology 3975 Fair ...

  15. Development and characterization of nickel catalysts supported in CeO2-ZrO2-Al2O3, CeO2-La2O3-Al2O3 e ZrO2-La2O3-Al2O3 matrixes evaluated for methane reforming reactions

    International Nuclear Information System (INIS)

    Abreu, Amanda Jordão de

    2012-01-01

    Nowadays, the methane reforming is large interest industrial for the take advantage of these gas in production the hydrogen and synthesis gas (syngas). Among in the reactions of methane stand of the reactions steam reforming and carbon dioxide reforming of methane. The main catalysts uses in the methane reforming is Ni/Al 2 O 3 . However, the supported-nickel catalyst is susceptible to the deactivation or the destruction by coke deposition. The carbon dissolves in the nickel crystallite and its diffuses through the nickel, leading for formation of the carbon whiskers, which results in fragmentation of the catalyst. Modification of such catalysts, like incorporation of suitable promoters, is desirable to achieve reduction of the methane hydrogenolysis and/or promotion of the carbon gasification. Catalysts 5%Ni/Al 2 O 3 supported on solid solutions formed by ZrO 2 -CeO 2 , La 2 O 3 and CeO 2 -ZrO 2 -La 2 O 3 were prepared, characterized and evaluated in reactions steam and carbon dioxide reforming and partial oxidation of methane with objective the value effect loading solution solid in support. The supports were prepared by co-precipitation method and catalysts were prepared by impregnation method and calcined at 500 deg C. The supports and catalysts were characterized by Nitrogen Adsorption, method -rays diffraction (XRD), X-rays dispersive spectroscopy (XDS), spectroscopy in the region of the ultraviolet and the visible (UV-vis NIR) to and temperature programmed reduction (TPR), Raman Spectroscopy, X-ray absorption spectroscopy and Thermogravimetric Analysis. After all the catalytic reactions check which the addition of solid solution is beneficial for Ni/Al 2 O 3 catalysts and the best catalysts are Ni/CeO 2 -La 2 O 3 -Al 2 O 3 . (author)

  16. Paediatric Interventional Uroradiology

    International Nuclear Information System (INIS)

    Barnacle, Alex M.; Wilkinson, A. Graham; Roebuck, Derek J.

    2011-01-01

    Paediatric interventional uroradiology lies at the intersection of the disciplines of paediatric interventional radiology and paediatric endourology. Interdisciplinary collaboration has led to the development of new techniques and refinement of procedures adopted from adult practice. This article reviews the major procedures used in paediatric interventional uroradiology, with emphasis on nephrostomy, percutaneous nephrolithotomy, balloon-burst pyeloplasty, and antegrade ureteric stenting.

  17. Inmunopatogenia del pénfigo vulgar y el pénfigo foliáceo = Immunopathogenesis of pemphigus vulgaris and pemphigus foliaceus

    Directory of Open Access Journals (Sweden)

    Valencia Ocampo, Óscar Jairo

    2011-09-01

    Full Text Available El pénfigo vulgar y el pénfigo foliáceo son enfermedades ampollosas autoinmunes mediadas por autoanticuerpos dirigidos contra proteínas de los desmosomas, las desmogleínas 1 y 3. Están asociadas con moléculas del complejo mayor de histocompatibilidad (HLA que por su estructura tienen la capacidad de presentar péptidos antigénicos de las desmogleínas. En los individuos afectados se han descrito la presencia de linfocitos T y B autorreactivos y alteraciones en la regulación del sistema inmune con desequilibrio de las respuestas Th1/Th2. No se conocen con precisión los mecanismos de daño pero la investigación actual indica que los anticuerpos tienen un papel patogénico, inician diferentes cascadas de señalización que provocan la acantólisis y apoptosis de los queratinocitos. El conocimiento de la inmunopatogenia de las enfermedades ampollosas autoinmunes ha permitido el desarrollo y la puesta en práctica de nuevas alternativas terapéuticas.

  18. Influence of synthesis conditions on the crystal structure of the powder formed in the ZrO2 - Ce2O3/CeO2 system

    International Nuclear Information System (INIS)

    Popov, V V; Menushenkov, A P; Khubbutdinov, R M; Sharapov, A S; Svetogorov, R D; Zubavichus, Ya V; Kurilkin, V V

    2016-01-01

    Influence of synthesis conditions (type of atmosphere, reduction and oxidation, annealing temperature) on the chemical composition and structure of the compounds formed in the “ZrO 2 - Ce 2 O 3 / CeO 2 ” system has been investigated by X-ray absorption fine structure (XAFS) spectroscopy combined with X-ray diffraction (XRD) and thermogravimetric analysis (TGA). It is revealed that isothermal annealing of precursor at temperatures less than 1000 °C in air leads to formation of Ce 0.5 Zr 0.5 O 2 powders with cubic fluorite-type structure (Fm-3m). Further increase of annealing temperatures above 1000 °C causes decomposition of formed crystal structure into two phases: cubic and tetragonal. Annealing in reduction hydrogen atmosphere causes formation of Ce 4 + 2xCe 3 + 2-2xZr 2 O 7 + x compounds with intermediate valency of cerium, where value of x depends on the reducing conditions and treatment parameters of precursor. Annealing in vacuum at 1400 °C strongly reduces the content of Ce 4 + in a powder samples and leads to formation of pyrochlore structure (space group Fd-3 m ) with practically Ce 3+ valence state. (paper)

  19. Estudo do comportamento dos linfócitos derivados do timo em pacientes com pênfigo foliáceo na presença de levamisol

    Directory of Open Access Journals (Sweden)

    Maria Dolores Porto Acedo

    1984-03-01

    Full Text Available Foram estudados linfócitos T de pacientes portadores de pênfigo foliáceo em relação à sua capacidade de formar rosáceas "E'. diante de diferentes concentrações do imunopotenciador levamisol. O levamisol é uma substância que estimula formação de rosáceas de linfócitos T ativos em indivíduos normais. Os linfócitos de pacientes antes da corticoterapia sistêmica não responderam ao levamisol; já os linfócitos de pacientes em tratamento com corticóides tiveram inibida sua capacidade de formar rosáceas. Esses achados sugerem alteração no metabolismo celular dos linfócitos de pacientes penfigosos devido provavelmente a alguma falha no sistema enzimático dessas células envolvendo a fosfodiesterase do AMPc.T lymphocytes from patients with Pemphigus foliaceus were studied fortheir ability to form E rosettes in thepresence of different concentrations of the immunostimulant levamisole. Lymphocytes from patients before systemic corticotherapy did not show stimulation when incubated with levamisole. Lymphocytes from patients submitted to corticotherapy had their ability to form rosettes inhibited. Those data suggest that the lymphocytes from patients with Pemphigus foliaceus may have some kind of defect in the phosphodiesterase of cyclic AMP.

  20. Renewable H2 from glycerol steam reforming: effect of La2O3 and CeO2 addition to Pt/Al2O3 catalysts.

    Science.gov (United States)

    Montini, Tiziano; Singh, Rakesh; Das, Piyali; Lorenzut, Barbara; Bertero, Nicolás; Riello, Pietro; Benedetti, Alvise; Giambastiani, Giuliano; Bianchini, Claudio; Zinoviev, Sergey; Miertus, Stanislav; Fornasiero, Paolo

    2010-05-25

    Glycerol is the main byproduct of biodiesel production and its increased production volume derives from the increasing demand for biofuels. The conversion of glycerol to hydrogen-rich mixtures presents an attractive route towards sustainable biodiesel production. Here we explored the use of Pt/Al(2)O(3)-based catalysts for the catalytic steam reforming of glycerol, evidencing the influence of La(2)O(3) and CeO(2) doping on the catalyst activity and selectivity. The addition of the latter metal oxides to a Pt/Al(2)O(3) catalyst is found to significantly improve the glycerol steam reforming, with high H(2) and CO(2) selectivities. A good catalytic stability is achieved for the Pt/La(2)O(3)/Al(2)O(3) system working at 350 degrees C, while the Pt/CeO(2)/Al(2)O(3) catalyst sharply deactivates after 20 h under similar conditions. Studies carried out on fresh and exhausted catalysts reveal that both systems maintain high surface areas and high Pt dispersions. Therefore, the observed catalyst deactivation can be attributed to coke deposition on the active sites throughout the catalytic process and only marginally to Pt nanoparticle sintering. This work suggests that an appropriate support composition is mandatory for preparing high-performance Pt-based catalysts for the sustainable conversion of glycerol into syngas.

  1. Template-assisted formation of microsized nanocrystalline CeO2 tubes and their catalytic performance in the carboxylation of methanol

    Directory of Open Access Journals (Sweden)

    Jörg J. Schneider

    2011-11-01

    Full Text Available Polymethylmethacrylate (PMMA/ceria composite fibres were synthesized by using a sequential combination of polymer electrospinning, spray-coating with a sol, and a final calcination step to yield microstructured ceria tubes, which are composed of nanocrystalline ceria particles. The PMMA template is removed from the organic/inorganic hybrid material by radio frequency (rf plasma etching followed by calcination of the ceramic green-body fibres. Microsized ceria (CeO2 tubes, with a diameter of ca. 0.75 µm, composed of nanocrystalline agglomerated ceria particles were thus obtained. The 1-D ceramic ceria material was characterized by X-ray diffraction, scanning electron microscopy (SEM, high-resolution transmission electron microscopy (HRTEM, UV–vis and photoluminescence spectroscopy (PL, as well as thermogravimetric analysis (TGA. Its catalytic performance was studied in the direct carboxylation of methanol with carbon dioxide leading to dimethyl carbonate [(CH3O2CO, DMC], which is widely employed as a phosgene and dimethyl sulfate substitute, and as well as a fuel additive.

  2. Template-assisted formation of microsized nanocrystalline CeO(2) tubes and their catalytic performance in the carboxylation of methanol.

    Science.gov (United States)

    Schneider, Jörg J; Naumann, Meike; Schäfer, Christian; Brandner, Armin; Hofmann, Heiko J; Claus, Peter

    2011-01-01

    Polymethylmethacrylate (PMMA)/ceria composite fibres were synthesized by using a sequential combination of polymer electrospinning, spray-coating with a sol, and a final calcination step to yield microstructured ceria tubes, which are composed of nanocrystalline ceria particles. The PMMA template is removed from the organic/inorganic hybrid material by radio frequency (rf) plasma etching followed by calcination of the ceramic green-body fibres. Microsized ceria (CeO(2)) tubes, with a diameter of ca. 0.75 µm, composed of nanocrystalline agglomerated ceria particles were thus obtained. The 1-D ceramic ceria material was characterized by X-ray diffraction, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), UV-vis and photoluminescence spectroscopy (PL), as well as thermogravimetric analysis (TGA). Its catalytic performance was studied in the direct carboxylation of methanol with carbon dioxide leading to dimethyl carbonate [(CH(3)O)(2)CO, DMC], which is widely employed as a phosgene and dimethyl sulfate substitute, and as well as a fuel additive.

  3. X-ray and neutron powder investigations of pure and yttrium doped CeO2 at temperatures up to 1600 K

    International Nuclear Information System (INIS)

    Berber, K.; Martin, U.; Mursic, Z.; Schneider, J.; Boysen, H.; Frey, F.

    1991-01-01

    Ceria, CeO 2 powders and sintermaterials with different amounts of yttria, Y 2 O 3 , (0-10 mole %) were investigated up to 1600 K by X-ray and neutron powder diffraction. In the sample with 3 mole % yttria the onset of a solid-state reaction or a kind of phase change at 900 K is indicated by a change of the lattice expansion coefficient and by an increase of the slope of the B iso (T) curve. Microstrains are present in the sintered material above 900 K. Anharmonic contributions to the temperature factor of the oxygens become significant at higher temperatures. We deduce from a non-zero part B T ≠0 some static disorder within the O-sublattice. Pdf-maps of the oxygens show clearly deformations of the 'normal' isotropic behaviour, but exceptional smearing out or even closed pathways are not observed. Thus, the superior anionic conductivity of this material is not reflected by the features of the averaged structure. It is most likely due to a disordered 'interface-structure' between ordered domains. A temperature dependent 'structured' background scattering supports this conclusion. (author) 6 figs., 9 refs

  4. Elevated Temperature Solid Particle Erosion Performance of Plasma-Sprayed Co-based Composite Coatings with Additions of Al2O3 and CeO2

    Science.gov (United States)

    Nithin, H. S.; Desai, Vijay; Ramesh, M. R.

    2017-11-01

    In this paper, investigation into solid particle erosion behavior of atmospheric plasma-sprayed composite coating of CoCrAlY reinforced with Al2O3 and CeO2 oxides on Superni 76 at elevated temperature of 600 °C is presented. Alumina particles are used as erodent at two impact angles of 30° and 90°. The microstructure, porosity, hardness, toughness and adhesion properties of the as-sprayed coatings are studied. The effects of temperature and phase transformation in the coatings during erosion process are analyzed using XRD and EDS techniques. Optical profilometer is used for accurate elucidation of erosion volume loss. CoCrAlY/CeO2 coating showed better erosion resistance with a volume loss of about 50% of what was observed in case of CoCrAlY/Al2O3/YSZ coating. Lower erosion loss is observed at 90° as compared to 30° impact angle. The erosion mechanism evaluated using SEM micrograph revealed that the coatings experienced ductile fracture exhibiting severe deformation with unusual oxide cracks. Reinforced metal oxides provide shielding effect for erodent impact, enabling better erosion resistance. The oxidation of the coating due to high-temperature exposure reforms erosion process into oxidation-modified erosion process.

  5. Co3O4/Sm-Doped CeO2/Co3O4Trilayer Coating on AISI 441 Interconnect for Solid Oxide Fuel Cells.

    Science.gov (United States)

    Shen, Fengyu; Lu, Kathy

    2017-02-22

    In this work, a novel Co/Sm-doped CeO 2 (SDC)/Co trilayer of ∼6 μm is deposited by alternating electrodeposition and electrophoresis and oxidized to a Co 3 O 4 /SDC/Co 3 O 4 trilayer structure. This coating is unique and effective in the following aspects: (1) The area specific resistance of the coated interconnect is more stable and lower than that of the uncoated interconnect after thermal treatment at 800 °C for 400 h. (2) The Co 3 O 4 /SDC/Co 3 O 4 coating layer can effectively inhibit Cr diffusion and evaporation and significantly slow the oxidation rate of the interconnect. (3) The Sm 0.5 Sr 0.5 Co 0.2 Fe 0.8 O 3 cathode in the electrolyte/cathode/interconnect half-cell retains its initial stoichiometry after 100 h of the thermal treatment. Subsequently, the ohmic resistance R Ω , high frequency polarization resistance R H , and low frequency polarization resistance R L of the half-cell with the Co 3 O 4 /SDC/Co 3 O 4 coated interconnect are all smaller than those of the half-cell with the bare interconnect. The Co 3 O 4 /SDC/Co 3 O 4 coating layer has great advantages to be used as a protective layer for the metallic interconnect in solid oxide fuel cells to improve cell performance, stability, and durability.

  6. Dehydrogenation of Surface-Oxidized Mixtures of 2LiBH4 + Al/Additives (TiF3 or CeO2

    Directory of Open Access Journals (Sweden)

    Juan Luis Carrillo-Bucio

    2017-11-01

    Full Text Available Research for suitable hydrogen storage materials is an important ongoing subject. LiBH4–Al mixtures could be attractive; however, several issues must be solved. Here, the dehydrogenation reactions of surface-oxidized 2LiBH4 + Al mixtures plus an additive (TiF3 or CeO2 at two different pressures are presented. The mixtures were produced by mechanical milling and handled under welding-grade argon. The dehydrogenation reactions were studied by means of temperature programmed desorption (TPD at 400 °C and at 3 or 5 bar initial hydrogen pressure. The milled and dehydrogenated materials were characterized by scanning electron microscopy (SEM, X-ray diffraction (XRD, and Fourier transformed infrared spectroscopy (FT-IR The additives and the surface oxidation, promoted by the impurities in the welding-grade argon, induced a reduction in the dehydrogenation temperature and an increase in the reaction kinetics, as compared to pure (reported LiBH4. The dehydrogenation reactions were observed to take place in two main steps, with onsets at 100 °C and 200–300 °C. The maximum released hydrogen was 9.3 wt % in the 2LiBH4 + Al/TiF3 material, and 7.9 wt % in the 2LiBH4 + Al/CeO2 material. Formation of CeB6 after dehydrogenation of 2LiBH4 + Al/CeO2 was confirmed.

  7. Hydrogen Production by Ethanol Steam Reforming (ESR over CeO2 Supported Transition Metal (Fe, Co, Ni, Cu Catalysts: Insight into the Structure-Activity Relationship

    Directory of Open Access Journals (Sweden)

    Michalis Konsolakis

    2016-03-01

    Full Text Available The aim of the present work was to investigate steam reforming of ethanol with regard to H2 production over transition metal catalysts supported on CeO2. Various parameters concerning the effect of temperature (400–800 °C, steam-to-carbon (S/C feed ratio (0.5, 1.5, 3, 6, metal entity (Fe, Co, Ni, Cu and metal loading (15–30 wt.% on the catalytic performance, were thoroughly studied. The optimal performance was obtained for the 20 wt.% Co/CeO2 catalyst, achieving a H2 yield of up to 66% at 400 °C. In addition, the Co/CeO2 catalyst demonstrated excellent stability performance in the whole examined temperature range of 400–800 °C. In contrast, a notable stability degradation, especially at low temperatures, was observed for Ni-, Cu-, and Fe-based catalysts, ascribed mainly to carbon deposition. An extensive characterization study, involving N2 adsorption-desorption (BET, X-ray diffraction (XRD, Scanning Electron Microscopy (SEM/EDS, X-ray Photoelectron Spectroscopy (XPS, and Temperature Programmed Reduction (H2-TPR was undertaken to gain insight into the structure-activity correlation. The excellent reforming performance of Co/CeO2 catalysts could be attributed to their intrinsic reactivity towards ethanol reforming in combination to their high surface oxygen concentration, which hinders the deposition of carbonaceous species.

  8. Total catalytic wet oxidation of phenol and its chlorinated derivates with MnO2/CeO2 catalyst in a slurry

    Directory of Open Access Journals (Sweden)

    A. J. Luna

    2009-09-01

    Full Text Available In the present work, a synthetic effluent of phenol was treated by means of a total oxidation process-Catalyzed Wet Oxidation (CWO. A mixed oxide of Mn-Ce (7:3, the catalyst, was synthesized by co-precipitation from an aqueous solution of MnCl2 and CeCl3 in a basic medium. The mixed oxide, MnO2/CeO2, was characterized and used in the oxidation of phenol in a slurry reactor in the temperature range of 80-130ºC and pressure of 2.04-4.76 MPa. A phenol solution containing 2.4-dichlorophenol and 2.4-dichlorophenoxyacetic acid was also degraded with good results. A lumped kinetic model, with two parallel reaction steps, fits precisely with the integrated equation and the experimental data. The kinetic parameters obtained are in agreement with the Arrhenius equation. The activation energies were determined to be 38.4 for the total oxidation and 53.4 kJ/mol for the organic acids formed.

  9. Impact of catalytically cracked jatropha oil using CeO2 and SiO2 as catalysts on DI diesel engine performance and emission characteristics

    Directory of Open Access Journals (Sweden)

    Mylswamy Thirunavukkarasu

    2017-01-01

    Full Text Available The biooil is thermally cracked under catalytic environment in a catalytic cracking process. This process is able to replace the transesterification process to match the biofuel properties with diesel. In this study the silicon dioxide and cerium oxide were chosen as catalyst for cracking the jatropha vegetable oil. The catalytically cracked jatropha biofuel gas is delivered at constant rate to the inlet manifold of the diesel engine. Before and after cracking, the characteristics of the catalysts were analyzed using scanning electron microscope and X-ray diffraction. The condensed cracked jatropha biofuel properties were analyzed with the results of Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry analysis, and it matches with the diesel fuel. From the experimental results, the increase in brake thermal efficiency of the engine with higher oxides of nitrogen emission was observed compared with diesel for both the catalytically cracked jatropha biofuels. Notably, SiO2 as catalyst showed the better mixing towards homogeneity with higher performance and emission results than the CeO2 as catalyst.

  10. Fe-doped CeO2 solid solutions: Substituting-site doping versus interstitial-site doping, bulk doping versus surface doping

    Science.gov (United States)

    Bao, Huizhi; Qian, Kun; Fang, Jun; Huang, Weixin

    2017-08-01

    Doping CeO2 cubic fluorite with transitional metal ions can effectively improve its redox behavior, oxygen storage capacity and catalytic performance, but the relevant fundamental understanding of the promotion effect is still insufficient due to the difficulty on determining the distribution of dopant. We herein demonstrate an effective approach to determine this dopant distribution by combining X-ray absorption spectroscopy and selective chemisorption. Cubic CexFe1-xO2 fluorite solid solutions (x ≥ 0.70) were prepared by co-precipitation method. With the increasing of Fe molar ratio in CexFe1-xO2, Fe3+ initially substitutes Ce4+ and/or occupy intersitial sites with x ≥ 0.80, and then transfers to form sub-Fe2O3 structure in fluorite lattice as more Fe3+ are present; meanwhile, the Fe3+ doping initially occurs only in the bulk with x ≥ 0.96 and then extends to the surface with 0.87 ≤ x fluorite solid solutions at the molecular level that are of great importance for the fundamental understanding of their properties.

  11. Influence of ɣ and ultrasonic irradiations on the physicochemical properties of CeO2-Fe2O3-Al2O3 for textile dyes removal applications

    Science.gov (United States)

    Ibrahim, Marwa M.; El-Molla, Sahar A.; Ismail, Sahar A.

    2018-04-01

    In this study highly effective adsorbent ternary mixed oxide CeO2-Fe2O3-Al2O3 was prepared by precipitation method. Various methods used to treat the mixed hydroxide like calcination, ultrasonic, hydrothermal and ɣ radiation with different doses to obtain the ternary mixed oxide. XRD, TEM, EDX, FTIR and SBET are used to study the physicochemical properties of nanoparticles. The CFAH and CFAɣ0.8 have the different morphologies and high surface area. Batch adsorption experiments were performed to remove anionic Remazol Red RB-133 dye. The experimental data showed that The CFAH and CFAɣ0.8 have high adsorption rate for removing of dye. The removal of dye is enhanced by ultrasonic radiation and high temperature. The adsorption process was fitted well for pseudo second order kinetics and followed the Freundlich isotherm model. In addition to, Thermodynamic results of adsorption process displayed that, the adsorption of dye on adsorbent was spontaneous, endothermic and chemisorptions process.

  12. Density Functional Theory plus Hubbard U Study of the Segregation of Pt to the CeO2- x Grain Boundary.

    Science.gov (United States)

    Zhou, Guoli; Li, Pan; Ma, Qingmin; Tian, Zhixue; Liu, Ying

    2018-03-14

    Grain boundaries (GBs) can be used as traps for solute atoms and defects, and the interaction between segregants and GBs is crucial for understanding the properties of nanocrystalline materials. In this study, we have systematically investigated the Pt segregation and Pt-oxygen vacancies interaction at the ∑3 (111) GB in ceria (CeO 2 ). The Pt atom has a stronger tendency to segregate to the ∑3 (111) GB than to the (111) and (110) free surfaces, but the tendency is weaker than to (112) and (100). Lattice distortion plays a dominant role in Pt segregation. At the Pt-segregated-GB (Pt@GB), oxygen vacancies prefer to form spontaneously near Pt in the GB region. However, at the pristine GB, oxygen vacancies can only form under O-poor conditions. Thus, Pt segregation to the GB promotes the formation of oxygen vacancies, and their strong interactions enhance the interfacial cohesion. We propose that GBs fabricated close to the surfaces of nanocrystalline ceria can trap Pt from inside the grains or other types of surface, resulting in the suppression of the accumulation of Pt on the surface under redox reactions, especially under O-poor conditions.

  13. Benchmarking road safety performance: Identifying a meaningful reference (best-in-class).

    Science.gov (United States)

    Chen, Faan; Wu, Jiaorong; Chen, Xiaohong; Wang, Jianjun; Wang, Di

    2016-01-01

    For road safety improvement, comparing and benchmarking performance are widely advocated as the emerging and preferred approaches. However, there is currently no universally agreed upon approach for the process of road safety benchmarking, and performing the practice successfully is by no means easy. This is especially true for the two core activities of which: (1) developing a set of road safety performance indicators (SPIs) and combining them into a composite index; and (2) identifying a meaningful reference (best-in-class), one which has already obtained outstanding road safety practices. To this end, a scientific technique that can combine the multi-dimensional safety performance indicators (SPIs) into an overall index, and subsequently can identify the 'best-in-class' is urgently required. In this paper, the Entropy-embedded RSR (Rank-sum ratio), an innovative, scientific and systematic methodology is investigated with the aim of conducting the above two core tasks in an integrative and concise procedure, more specifically in a 'one-stop' way. Using a combination of results from other methods (e.g. the SUNflower approach) and other measures (e.g. Human Development Index) as a relevant reference, a given set of European countries are robustly ranked and grouped into several classes based on the composite Road Safety Index. Within each class the 'best-in-class' is then identified. By benchmarking road safety performance, the results serve to promote best practice, encourage the adoption of successful road safety strategies and measures and, more importantly, inspire the kind of political leadership needed to create a road transport system that maximizes safety. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. An Eectromyographic Ccomparison Between the Activities of Temporal and Masseter Muscles in Class III Skeletal

    Directory of Open Access Journals (Sweden)

    T Hossein-Zadeh-Nik

    2002-02-01

    Full Text Available Electromyographic (EMG investigations about the activities of the muscles have been the focus of attention for many years. In the field of orthodontics, investigators, among other things, tried to evaluate correlation between EMG activity, occlusal relationships and craniofacial morphology to analyze the effect of muscular activity, as an etiological factor in malocclusion. The purpose of the present investigation is to analyze the effect of EMG activity of temporal and masseter muscles quantitatively in skeletal class III malocclusion. 26 patients (9 to If years old, with class III malocclusion were selected and their EMG activity of temporal and masseter muscles in rest position, centric occlusion, clenching, mastication and swallowing were compared with 20 normal children at the same age range. Then the statistical correlation between 13 cephalometric parameters and EMG activities were analyzed and then the regression analysis was performed and the results were as follows:1- The mean amplitude of masseter and temporal muscles activity in rest position, centric occlusion, mastication, and clenching in class III samples were greater than normal group (PO.05.2- The mean duration of masseter and temporal muscles activity in rest position and centric occlusion in class III samples were more than normal group (PO.05.3- According to regression analysis, a linear correlation was observed between ANB angle and temporal muscle activity in rest and centric occlusion that was not observed in other cases.The findings of this study showed that difference in temporal muscle activity in class III malocclusion, in comparison with the normal group, is correlated with skeletal morphology of the face, but according to other investigations it is not ture for the masseter muscle.

  15. Craniofacial changes in Class III malocclusion as related to skeletal and dental maturation.

    Science.gov (United States)

    Baccetti, Tiziano; Reyes, Brian C; McNamara, James A

    2007-08-01

    In this large cross-sectional study, we aimed to analyze growth trends in white subjects with Class III malocclusion using both skeletal and dental maturation staging. The sample consisted of 1091 pretreatment lateral cephalometric records of Class III patients (560 female, 531 male). Cephalometric dentoskeletal measurements were compared at subsequent stages in cervical vertebral maturation and Hellman's categorization of dental development by means of ANOVA with Bonferroni post-hoc tests in both sexes separately. The findings indicated that, in Class III malocclusion, the pubertal peak in mandibular growth occurs between stages 3 and 4 of cervical vertebral maturation, with average increases in total mandibular length of about 8 and 5.5 mm in Class III boys and girls, respectively. Significant changes in total mandibular length occur until young adulthood (18 years on average), with increases between late maturation stages (4 through 6) that were twice as large as in subjects with normal occlusion for the Class III females, and 3 times as large as in subjects with normal occlusion for the Class III males. Growth trends toward accentuated Class III profile and increased vertical dimension of the face also become apparent at late developmental stages (corresponding with complete eruption of the second and third molars).

  16. Soft tissue profile changes after Functional Mandibular Advancer or Herbst appliance treatment in class II patients.

    Science.gov (United States)

    Hourfar, Jan; Lisson, Jörg Alexander; Gross, Ulrich; Frye, Linda; Kinzinger, Gero Stefan Michael

    2018-03-01

    The objective of the present study is to compare the effects on soft tissue profile in class II patients after treatment with either "Functional Mandibular Advancer" (FMA) or Herbst appliance. The study included n = 42 patients treated with either FMA (n = 21) or Herbst appliance (n = 21) by the same experienced orthodontist. The treatment followed a single-step advancement protocol. Lateral cephalograms were analyzed through a set of customized measurements. The actual therapeutic effect was calculated using data from a growth survey. After testing for normal distribution and homogeneity of variance, data were analyzed by one-sample Student's t tests and independent Student's t tests. Statistical significance was set at p profile were found in FMA and Herbst appliance patients. All remaining variables revealed no significant differences. Treatment-related changes on the facial soft tissue profile could be regarded similar in class II patients treated with FMA or Herbst appliance. No treatment-related changes that were specific for FMA or Herbst appliance could be identified. Only moderate changes were noted comparing pre- and posttreatment soft tissue profiles. Despite proven differences in skeletal and dental treatment effects, the facial profile has not to be taken into consideration when choosing between FMA and Herbst appliance for class II treatment.

  17. Combination of interventions can change students’ epistemological beliefs

    Directory of Open Access Journals (Sweden)

    Calvin S. Kalman

    2015-12-01

    Full Text Available This study was based on the hypothesis that students’ epistemological beliefs could become more expertlike with a combination of appropriate instructional activities: (i preclass reading with metacognitive reflection, and (ii in-class active learning that produces cognitive dissonance. This hypothesis was tested through a five-year study involving close to 1000 students at two institutions, in four physics courses. Using an experimental design, data from student interviews, writing product assessments, and the Discipline-Focused Epistemological Beliefs Questionnaire (DFEBQ we demonstrate that the beliefs of novice science learners became more expertlike on 2 of the 4 DFEBQ factors. We conclude that a combination of an activity that gets students to examine textual material metacognitively (Reflective Writing with one or more types of in-class active learning interventions can promote positive change in students’ epistemological beliefs.

  18. Combination of interventions can change students' epistemological beliefs

    Science.gov (United States)

    Kalman, Calvin S.; Sobhanzadeh, Mandana; Thompson, Robert; Ibrahim, Ahmed; Wang, Xihui

    2015-12-01

    This study was based on the hypothesis that students' epistemological beliefs could become more expertlike with a combination of appropriate instructional activities: (i) preclass reading with metacognitive reflection, and (ii) in-class active learning that produces cognitive dissonance. This hypothesis was tested through a five-year study involving close to 1000 students at two institutions, in four physics courses. Using an experimental design, data from student interviews, writing product assessments, and the Discipline-Focused Epistemological Beliefs Questionnaire (DFEBQ) we demonstrate that the beliefs of novice science learners became more expertlike on 2 of the 4 DFEBQ factors. We conclude that a combination of an activity that gets students to examine textual material metacognitively (Reflective Writing) with one or more types of in-class active learning interventions can promote positive change in students' epistemological beliefs.

  19. Guideline for Early Interventions

    Science.gov (United States)

    2006-04-01

    RTO-MP-HFM-134 6 - 1 Guideline for Early Interventions Maaike de Vries Impact Foundation, Dutch Knowledge & Advice Centre for Post...assistance, also referred to as ‘ early interventions ’ or ‘debriefing’, is offered following shocking events. These may be large scale disasters or...calamities, but also military deployment and individual incidents. During the last years, the demand for early interventions has been increasing

  20. Tanaidáceos (Crustacea: Peracarida de los litorales de Guerrero y Oaxaca, México Littoral tanaidaceans (Crustacea: Peracarida from Guerrero and Oaxaca, Mexico

    Directory of Open Access Journals (Sweden)

    Jani Jarquín-González

    2010-10-01

    Full Text Available Los tanaidáceos son componentes esenciales de las cadenas tróficas del bentos marino, son fuente de alimento para especies de relevancia comercial y para otros organismos marinos. A pesar de su importancia, el conocimiento del grupo se ha rezagado debido a los problemas relacionados con su biología y taxonomía, y por la carencia de muestreos exhaustivos y sistemáticos; así, en las costas de Guerrero y Oaxaca sólo se había registrado 1 género. Por lo anterior, el objetivo fue conocer la composición específica y los patrones de distribución de los tanaidáceos litorales de Guerrero y Oaxaca. De 4 275 ejemplares, se identificaron 6 familias y 9 morfotipos: Hexapleomera robusta, Sinelobus stanfordi, Leptochelia cf. dubia, Paratanais cf. denticulatus, Paradoxapseudes cf. garthi, Apseudormorpha sp., Cyclopoapseudes cf. indecorus, Synapseudes sp. y Parapseudes pedispinis. Todos son registros nuevos para el litoral de Guerrero y Oaxaca. Se amplía el intervalo de distribución hacia el norte, para H. robusta de islas Galápagos a Guerrero. Para S. stanfordi y P. pedispinis se proporcionan localidades intermedias que rompen con la distribución disyunta previa en el Pacífico oriental. Hay 6 especies, posiblemente nuevas, con distribución restringida; 2 son de amplia distribución y 1 restringida al Pacífico oriental tropical.The tanaidaceans are essential components in food chains of marine benthos, since they are the main food source for commercially important species and other marine organisms. Despite their importance, problems related to their biology and taxonomy have delayed the understanding of the group, as observed on the coasts of Guerrero and Oaxaca, where only 1 genus was previously known. The aim was to determine the species richness and distribution patterns of littoral tanaids from Guerrero and Oaxaca. A total of 4 275 specimens were collected and 6 families and 9 morphotypes have been identified: Hexapleomera robusta