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Sample records for cement western countries

  1. Social mix in Western countries

    NARCIS (Netherlands)

    Musterd, S.; Ostendorf, W.; Smith, S.J.; Elsinga, M.; Eng, O.S.; Fox O’Mahony, L.; Wachter, S.

    2012-01-01

    In Western countries, it appears to have become ‘fashionable’ for politicians who are engaged in urban issues to argue for more social mix of the population at the neighbourhood level. It is assumed that a concentration of poverty reproduces a lack of social opportunities. Therefore, a more balanced

  2. Peritoneal Dialysis in Western Countries.

    Science.gov (United States)

    Struijk, Dirk G

    2015-12-01

    better quality of life worldwide, but its prevalence is significantly lower than that of HD in all countries, with the exception of Hong Kong. Allowing reimbursement of PD but not HD has permitted to increase the use of PD over HD in many Asian countries like Hong Kong, Vietnam, Taiwan, Thailand, as well as in New Zealand and Australia over the last years. In the Western world, however, HD is still promoted, and the proportion of patients treated with PD decreases. Japan remains an exception in Asia where PD penetration is very low. Lack of adequate education of practitioners and information of patients might as well be reasons for the low penetration of PD in both the East and West. (2) Patient survival of PD varies between and within countries but is globally similar to HD. (3) Peritonitis remains the main cause of morbidity in PD patients. South Asian countries face specific issues such as high tuberculosis and mycobacterial infections, which are rare in developed Asian and Western countries. The infection rate is affected by climatic and socio-economic factors and is higher in hot, humid and rural areas. (4) Nevertheless, the promotion of a PD-first policy might be beneficial particularly for remote populations in emerging countries where the end-stage renal disease rate is increasing dramatically.

  3. Acute Kidney Injury in Western Countries.

    Science.gov (United States)

    Bouchard, Josée; Mehta, Ravindra L

    2016-10-01

    Acute kidney injury (AKI) is frequent and is associated with poor outcomes, including increased mortality, higher risk of chronic kidney disease, and prolonged hospital lengths of stay. The epidemiology of AKI mainly derives from studies performed in Western high-income countries. More limited data are available from Western low-income and middle-income countries (LMICs) located in Central and South America. In this review, we summarize the most recent data on the epidemiology of AKI in Western countries, aiming to contrast results from industrialized high-income countries with LMICs. The global picture of AKI in LMICs is not as well characterized as in the USA and Europe. In addition, in some LMICs, the epidemiology of AKI may vary depending on the region and socioeconomic status, which contributes to the difficulty of getting a better portrait of the clinical condition. In low-income regions and tropical countries, AKI is frequently attributed to diarrhea, infections, nephrotoxins, as well as obstetric complications. As opposed to the situation in high-income countries, access to basic care in LMICs is limited by economic constraints, and treatment is often delayed due to late presentation and recognition of the condition, which contribute to worse outcomes. In addition, dialysis is often not available or must be paid by patients, which further restricts its use. There are great disparities in the epidemiology of AKI between Western high-income countries and Western LMICs. In LMICs, education and training programs should increase the public awareness of AKI and improve preventive and basic treatments to improve AKI outcomes. (1) More than 90% of the patients recruited in AKI studies using KDIGO-equivalent criteria originate from North America, Europe, or Oceania, although these regions represent less than a fifth of the global population. However, the pooled incidence of AKI in hospitalized patients reaches 20% globally with moderate variance between regions. (2

  4. Solar Energy and the Western Asian Countries

    Science.gov (United States)

    De Morais Mendonca Teles, Antonio

    2016-07-01

    The Western Asian countries receive the most abundant solar radiation of the world. They also have enormous reserves of oil and natural gas. But the world reserves of those fuels will certainly diminish greatly as the worldwide demand for energy will increase steadily in the coming decades. And the suppliers of energy will have to contend with public concerns about the polluting effects of those fuels and the possible dangers of nuclear energy. Clearly a power source based on an non exhaustible and non-polluting fuel could be expected to find a role. It now appears that such a source is at hand in the solar energy. Here in this paper, under the principles in the United Nations' Agenda 21, we suggest to Western Asian countries, the study and own development of the following technologies based on solar energy; and comment about them: *photo-voltaic solar cell power plants - in the future, its cost per kilowatt-hour will probably be competitive as to other sources of electrical energy. A new technique, the solar non-imaging concentrator, with amorphous silicon-based thin films solar cells at the focus of the concentrators, can collect and intensify solar radiation far better than conventional concentrators do, thus reducing much more the cost; *bio-gas - using biological gas to produce energy and for heating/cooling purposes; *wind generation of electricity - it's nowadays, a non-expensive technique; *water pump for irrigation and human consuming, driving their power from photovoltaic cells; *and the study and own development of solar lasers for peaceful scientific studies. In this new kind of laser, the external necessary pumping energy comes from the high intensity of sunlight, produced with non-imaging concentrators. Solar lasers can give unexpected new great uses for mankind. Those achievements will require international cooperation and transfer of information, sustained research and development work, and some initial subsides by independent governments. Solar

  5. The behaviour of cemented backfill and the surrounding rockmass at western deep levels south mine

    CSIR Research Space (South Africa)

    York, G

    1992-11-01

    Full Text Available Cemented backfill is used at Western Deep Mine as local and regional support areas of high stopping width. The in situ performance is reported and compared to laboratory tests. A back analysis was carried out to obtain a more accurate value...

  6. Political mechanisms of sustainable energy development in western countries

    International Nuclear Information System (INIS)

    Yershin, Sh. A.; Yershin, Sh. C.

    2014-01-01

    This article is about the development of politic mechanisms in sustainable energy in western countries (primarily EC, USA). The development of sustainable energy in western countries should be greatly based on government and business support and common ways of such help are described below. Also shown the significance of development of sustainable energy, its importance for environmental protection and perspectives Key words: sustainable energy, government regulation, wind energy, EC, USA, biofuel

  7. A hybrid multidimensional approach to select a country for global cement plant location

    International Nuclear Information System (INIS)

    Ali, M.K.

    2015-01-01

    The globalization and saturated domestic markets force international firms to gradually expand their businesses across the borders to capture potential emerging markets. The decision to select a country for a new cement plant location demands analysis of a large number of factors. It is a multifaceted problem which requires investigation and prioritization of factors in a hierarchical way. This paper uses an FAHP (Fuzzy Analytic Hierarchy Process) based procedure proposing a practical framework for solution of the GCPLP (Global Cement Plant Location Problem). It deals with real world ambiguities and handles a broader spectrum of influencing factors. The criteria for selection of a country for a new cement plant installation are prioritized from the FAHP based evaluation made by experts. Different global databases including the World Bank are used for the fuzzy ratings of the alternatives. It has been learnt in this particular problem that cement specific and cost related factors are the most sensitive while legal regulations and economic conditions are relatively less sensitive for the decision makers. Therefore, the countries having strong lime stone reserves, cheaper fuel costs and good internal marketing positions are higher in ranking. The paper concludes with different rankings of the four countries analyzed which assist the strategic managers in making decisions on the basis of mathematically computed results. (author)

  8. A Hybrid Multidimensional Approach to Select a Country for Global Cement Plant Location

    Directory of Open Access Journals (Sweden)

    Muhammad Khurram Ali

    2015-04-01

    Full Text Available The globalization and saturated domestic markets force international firms to gradually expand their businesses across the borders to capture potential emerging markets. The decision to select a country for a new cement plant location demands analysis of a large number of factors. It is a multifaceted problem which requires investigation and prioritization of factors in a hierarchical way.This paper uses an FAHP (Fuzzy Analytic Hierarchy Process based procedure proposing a practical framework for solution of the GCPLP (Global Cement Plant Location Problem. It deals with real world ambiguities and handles a broader spectrum of influencing factors. The criteria for selection of a country for a new cement plant installation are prioritized from the FAHP based evaluation made by experts. Different global databases including the World Bank are used for the fuzzy ratings of the alternatives. It has been learnt in this particular problem that cement specific and cost related factors are the most sensitive while legal regulations and economic conditions are relatively less sensitive for the decision makers. Therefore, the countries having strong lime stone reserves, cheaper fuel costs and good internal marketing positions are higher in ranking. The paper concludes with different rankings of the four countries analyzed which assist the strategic managers in making decisions on the basis of mathematically computed results.

  9. WESTERN BALKANS’ COUNTRIES IN FOCUS OF GLOBAL ECONOMIC CRISIS

    OpenAIRE

    Engjell PERE; Albana HASHORVA

    2011-01-01

    The paper intends to analyze the impact of global economic crisis on the economies of Western Balkan Region. Albania, Bosnia & Herzegovina, Croatia, Macedonia (FYROM), Montenegro, Serbia, and Kosovo are part of this Region. The purpose of the paper is not to analyze the global crisis impact on specific sectors of the economies of the Western Balkan Countries, indeed, it focuses mainly on the macroeconomic level, identifying and analyzing fluctuations of major macroeconomic indicators of the e...

  10. International Students in Western Developed Countries: History, Challenges, and Prospects

    Science.gov (United States)

    Akanwa, Emmanuel E.

    2015-01-01

    Many scholars have described the various challenges international students face in Western developed countries including the United States, the United Kingdom, and Australia. Some of the challenges include differences in culture, language barriers, adjustment problems, medical concerns, pedagogical challenges, housing issues, lack of support…

  11. The Development of Green Care in Western European Countries

    NARCIS (Netherlands)

    Haubenhofer, D.K.; Elings, M.; Hassink, J.; Hine, R.E.

    2010-01-01

    This article represents a review of green care across Western European countries. The following questions are addressed: What is green care, and what are its basic goals? What are the most commonly known types of green care interventions, and how are they connected to each other? There are different

  12. How to establish endoscopic submucosal dissection in Western countries

    Science.gov (United States)

    Oyama, Tsuneo; Yahagi, Naohisa; Ponchon, Thierry; Kiesslich, Tobias; Berr, Frieder

    2015-01-01

    Endoscopic submucosal dissection (ESD) has been invented in Japan to provide resection for cure of early cancer in the gastrointestinal tract. Professional level of ESD requires excellent staging of early neoplasias with image enhanced endoscopy (IEE) to make correct indications for ESD, and high skills in endoscopic electrosurgical dissection. In Japan, endodiagnostic and endosurgical excellence spread through personal tutoring of skilled endoscopists by the inventors and experts in IEE and ESD. To translocate this expertise to other continents must overcome two fundamental obstacles: (1) inadequate expectations as to the complexity of IEE and ESD; and (2) lack of suitable lesions and master-mentors for ESD trainees. Leading endoscopic mucosal resection-proficient endoscopists must pioneer themselves through the long learning curve to proficient ESD experts. Major referral centers for ESD must arise in Western countries on comparable professional level as in Japan. In the second stage, the upcoming Western experts must commit themselves to teach skilled endoscopists from other referral centers, in order to spread ESD in Western countries. Respect for patients with early gastrointestinal cancer asks for best efforts to learn endoscopic categorization of early neoplasias and skills for ESD based on sustained cooperation with the masters in Japan. The strategy is discussed here. PMID:26523097

  13. Bringing Western-standard service stations to the Baltic countries

    International Nuclear Information System (INIS)

    Pesonen, H.

    1992-01-01

    Neste is the only Western oil company so far to have established a service station presence in the Baltic, with the exception of Norway's Statoil, which has one outlet near Tallinn Airport. Neste has an important logistical advantage compared to other companies in this respect as its two Finnish refineries are ideally located for supplying the region with high-quality petroleum products. Neste's first joint venture in the Baltic, Traffic Service, based in Estonia, was set up with Eesti Kutus in 1988 and opened its first service station in 1990. Other joint ventures are now up and running in Latvia, Lithuania, Poland, and St. Petersburg. A total of 10 - 15 stations, the majority strategically located along the route of the Via Baltica, are expected to be operational by the end of this year. The Neste network comprises a combination of new outlets and refurbished older stations that have been modernized to bring them up to Western standards. These offer a comprehensive range of fuels, lubricants, spare parts, and accessories, as well as food, confectionery, and coffee shop services. Some stations also offer repair and car wash facilities. Adapting to the transition from a communist economy to a Western, capitalist one has not been easy for the Baltic countries, and has inevitably created difficulties for companies like Neste, in areas such as legislation covering land ownership. Neste's joint ventures have also encountered difficulties in instilling the Western approach to business efficiency, and customer service in a workforce used to the Soviet retail system

  14. Prospective thermal power generation in the Western Balkan countries

    Directory of Open Access Journals (Sweden)

    Tomasović Nikola

    2015-01-01

    Full Text Available The aim of this paper is to analyze the expansion of the thermal generation in the long-term for the Western Balkan region. This paper concentrates on the estimation of long-term energy data for the (Western Balkan countries. The process was implemented by the use of the PRIMES model in order to perform simulations for the future growth of electricity supply and demand in the region. Two scenarios were applied. The first (Baseline scenario was based on the current energy path of each country and on the absence of any specific energy policy like tax emissions or renewable subsidies. The second (Reference scenario was practically a series of “environmental” sub-scenarios, based on specific energy subsidy policy applied to the electricity generated by renewable sources. Results were given for the period between 2015 and 2050 in 5-year steps and conclusions were made for the whole region. As such, the results can feed up trials of energy planning referring to the future energy condition.

  15. Understanding the motives for food choice in Western Balkan Countries.

    Science.gov (United States)

    Milošević, Jasna; Žeželj, Iris; Gorton, Matthew; Barjolle, Dominique

    2012-02-01

    Substantial empirical evidence exists regarding the importance of different factors underlying food choice in Western Europe. However, research results on eating habits and food choice in the Western Balkan Countries (WBCs) remain scarce. A Food Choice Questionnaire (FCQ), an instrument that measures the reported importance of nine factors underlying food choice, was administered to a representative sample of 3085 adult respondents in six WBCs. The most important factors reported are sensory appeal, purchase convenience, and health and natural content; the least important are ethical concern and familiarity. The ranking of food choice motives across WBCs was strikingly similar. Factor analysis revealed eight factors compared to nine in the original FCQ model: health and natural content scales loaded onto one factor as did familiarity and ethical concern; the convenience scale items generated two factors, one related to purchase convenience and the other to preparation convenience. Groups of consumers with similar motivational profiles were identified using cluster analysis. Each cluster has distinct food purchasing behavior and socio-economic characteristics, for which appropriate public health communication messages can be drawn. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Analysis of prospects for advanced nuclear reactors in western countries

    International Nuclear Information System (INIS)

    Di Sapia, R.

    1994-01-01

    Nuclear energy deployment faces stagnation in western european and north american countries as a result of barriers that have appeared over the years. Such barriers were identified in the domains of economics, public acceptance, energy policy, technology, licensing and regulations as well as environment and waste disposal. It is to the nuclear community and particularly the industry to take the initiative and the leadership role for the most significant approaches to overcome these barriers. These approaches include concentration of efforts, lowering of costs and financial risks and extensive use of the experience accumulated so far; clear setting of priorities and long-term global consideration of the energy issue; encouraging an appropriate, stable regulatory environment and harmonization of general safety objectives and principles, and adequate, globally consistent and clear information to the public. Also within the prime responsibility of the nuclear community belong the safe operation of existing plants; making available all necessary information to the public, the media and the political leaders, supporting the development and execution of national energy policies; supporting authorities in improving regulatory processes; taking all measures to improve economics of nuclear power; pursuing plans for the safe disposal of radioactive wastes. Governments should place energy issues in the appropriate priority level and encourage the establishment of an equally favourable environment for nuclear energy, including a greater consensus among controversial opinion representatives. Finally, authorities should established reasonable, transparent and predictable regulatory enviroments. This paper describes the barriers in a systematic way and proposes appropriate measures to overcame them

  17. Bespilotne letelice zapadnih zemalja / Unmanned aircraft of Western countries

    Directory of Open Access Journals (Sweden)

    Slavko Pokorni

    2002-11-01

    Full Text Available Trend sve češće primene bespilotnih letelica biće nastavljen nesumnjivo, i tokom ove decenije. U vezi s tim stiče se utisak da će razvoj borbenih bespilotnih letilica biti u usponu. Mada je u proteklom periodu težište bilo na razvoju bespilotnih letilica za vojne primene (gde su ulagana velika sredstva, a civilni sektor je, uglavnom, koristio rezultate razvoja vojnih bespilotnih letelica, u narednom periodu se očekuje porast ulaganja i u razvoj bespilotnih letelica u civilnom sektoru. Bespilotne letelice su imale značajnu ulogu u zadacima koje su obavljale multinacionalne snage u toku rata u Bosni i Hercegovini i agresije NATO-a na SRJ, pa je poznavanje karakteristika bespilotnih letelica, za pripadnike Vojske, od velikog značaja. U sažetom tabelarnom pregledu prikazani su podatci o bespilotnim letelicama uglavnom proizvođača iz zapadnih zemalja, što ne znači da ih ne proizvode i druge zemlje, posebno Ruska federacija kao i neke susedne zemlje (Bugarska, Hrvatska. / The increasingly frequent use of unmanned aircraft will continue unabated throughout this decade. About that the impression is that the development of combat drones will rise. Although in the past period the focus was on the development of unmanned military vehicles (where large funds were invested, and the civil sector used mainly the development of military drones, in the coming period, investment in the development of unmanned aircraft in the civil sector is expected . Unmanned aircraft played a significant role in the tasks performed by multinational forces during the war in Bosnia and Herzegovina and NATO aggression in the FR Yugoslavia, so the knowledge of the characteristics of drones for members of the Army is of great importance. The summary table shows the data on unmanned aircraft mainly manufactured from Western countries, which does not mean that they are not produced by other countries, especially the Russian Federation as well as some neighboring

  18. Factors affecting the use of prenatal care by non-western women in industrialized western countries: a systematic review

    NARCIS (Netherlands)

    Boerleider, A.W.; Wiegers, T.A.; Manniën, J.; Francke, A.L.; Deville, W.L.J.M.

    2013-01-01

    Background: Despite the potential of prenatal care for addressing many pregnancy complications and concurrent health problems, non-western women in industrialized western countries more often make inadequate use of prenatal care than women from the majority population do. This study aimed to give a

  19. Factors affecting the use of prenatal care by non-western women in industrialized western countries: a systematic review.

    NARCIS (Netherlands)

    Boerleider, A.W.; Wiegers, T.A.; Manniën, J.; Francke, A.L.; Devillé, W.L.J.M.

    2013-01-01

    Background: Despite the potential of prenatal care for addressing many pregnancy complications and concurrent health problems, non-western women in industrialized western countries more often make inadequate use of prenatal care than women from the majority population do. This study aimed to give a

  20. Factors affecting the use of prenatal care by non-western women in industrialized western countries: a systematic review

    NARCIS (Netherlands)

    Boerleider, A.W.; Wiegers, T.A.; Manniën, J.; Francke, A.L.; Devillé, W.L.J.M.

    2013-01-01

    Background Despite the potential of prenatal care for addressing many pregnancy complications and concurrent health problems, non-western women in industrialized western countries more often make inadequate use of prenatal care than women from the majority population do. This study aimed to give a

  1. The Prevalence and Management of Systemic Amyloidosis in Western Countries.

    Science.gov (United States)

    Nienhuis, Hans L A; Bijzet, Johan; Hazenberg, Bouke P C

    2016-04-01

    , evidence of systemic deposition, reliable typing, precursor assessment, severity of organ disease, risk assessment and prognosis, choice of treatment, and planned monitoring during follow-up. (1) AL amyloidosis is the most prevalent type of amyloidosis accounting for 65% of the amyloidosis-diagnosed patients in the UK and for 93% of the amyloidosis-diagnosed patients in China. The predisposition of men over women to develop AL amyloidosis might be higher in China than in Western countries (2:1 vs. 1.3:1). Both in the East and West, incidence increases with age. At the time of diagnosis, edema is twice as frequent and the proportion of renal involvement is higher in Chinese compared to Western patients. (2) Melphalan followed by autologous stem cell transplantation (ASCT) is the current standard therapy but is restricted to eligible patients. The efficacy and safety of bortezomib combined with dexamethasone were proven in Western patients and recently confirmed in a Chinese cohort. Recent studies in China and the US indicate that bortezomib induction prior to ASCT increases the response rate. Thalidomide and lenalidomide have shown benefit, but toxicity and lack of clinical evidence exclude these agents from first-line therapy. The green tea extract epigallocatechin-3-gallate is under investigation as an inhibitor of AL amyloid formation and a compound that might dissolve amyloid.

  2. Epilepsy misconceptions and stigma reduction: Current status in Western countries.

    Science.gov (United States)

    Herrmann, Lynn K; Welter, Elisabeth; Berg, Anne T; Perzynski, Adam T; Van Doren, Jamie R; Sajatovic, Martha

    2016-07-01

    This systematized literature review identified reports describing epilepsy misconceptions in the developed Western countries and research interventions focused on reducing these misconceptions. English language publications from January 2004 to January 2015 that described original research conducted in Europe, North/Central/South America, or Australia on misconceptions about epilepsy among the general public were used for this review. Eighty-one publications were selected. Most studies were conducted in the Americas (N=30) and Europe (N=31). Misconceptions and attitudes about epilepsy were assessed among clinical providers (N=9), family members of people with epilepsy (PWE) (N=5), teachers (N=11), students (N=22), and the general public (N=25). Most studies used structured questionnaires, sometimes adding open-ended questions. Misconceptions reflected socially exclusionary attitudes directed at PWE, ignorance about treatment, and overgeneralizations that are stigmatizing when applied to all PWE. Misconceptions were more prevalent in those with less education, lower socioeconomic status, and no exposure to PWE. There were only 12 intervention studies. While intervention studies were generally effective in improving attitudes, many were targeted to healthcare and education settings, were time-intensive, and impractical for broad general population implementation. None incorporated newer technology-based strategies regarding effective health communication approaches. Types of epilepsy misconceptions were similar in reports published over the last decade, although most referred to misconceptions that have already been previously described. Existing questionnaires may fail to identify more subtle forms of current misconceptions and negative attitudes. Few interventional studies specifically target epilepsy stigma. Practical and broad scalable approaches to destigmatize epilepsy may help reduce misconceptions. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Improving estimates of the prevalence of Female Genital Mutilation/Cutting among migrants in Western countries

    OpenAIRE

    Livia Elisa Ortensi; Patrizia Farina; Alessio Menonna

    2015-01-01

    Background: Female Genital Mutilation/Cutting (FGM/C) is an emerging topic in immigrant countries as a consequence of the increasing proportion of African women in overseas communities. Objective: While the prevalence of FGM/C is routinely measured in practicing countries, the prevalence of the phenomenon in western countries is substantially unknown, as no standardized methods exist yet for immigrant countries. The aim of this paper is to present an improved method of indirect estimation ...

  4. Gender inequalities in the education of the second generation in Western countries

    NARCIS (Netherlands)

    Fleischmann, Fenella; Kristen, Cornelia; Heath, Anthony F.; Brinbaum, Yaël; Deboosere, Patrick; Granato, Nadia; Jonsson, Jan O.; Kilpi-Jakonen, Elina; Lorenz, Georg; Lutz, Amy C.; Mos, David; Mutarrak, Raya; Phalet, Karen; Rothon, Catherine; Rudolphi, Frida; van de Werfhorst, Herman G.

    2014-01-01

    Drawing on comparative analyses from nine Western countries, we ask whether local-born children from a wide range of immigrant groups show patterns of female advantage in education that are similar to those prevalent in their host Western societies. We consider five outcomes throughout the

  5. Factors affecting the use of prenatal and postnatal care by women of non-western immigrant origin in industrialized western countries.

    NARCIS (Netherlands)

    Boerleider, A.W.; Devillé, W.L.J.M.; Francke, A.L.; Wiegers, T.A.

    2011-01-01

    Background: In many industrialized western countries immigrants constitute a substantial part of the population, which is also seen in the prenatal and postnatal care client population. Research in several industrialized western countries has shown that women of non-western immigrant origin make

  6. Factors affecting the use of prenatal care by non-western women in industrialized western countries: a systematic review

    Science.gov (United States)

    2013-01-01

    Background Despite the potential of prenatal care for addressing many pregnancy complications and concurrent health problems, non-western women in industrialized western countries more often make inadequate use of prenatal care than women from the majority population do. This study aimed to give a systematic review of factors affecting non-western women’s use of prenatal care (both medical care and prenatal classes) in industrialized western countries. Methods Eleven databases (PubMed, Embase, PsycINFO, Cochrane, Sociological Abstracts, Web of Science, Women’s Studies International, MIDIRS, CINAHL, Scopus and the NIVEL catalogue) were searched for relevant peer-reviewed articles from between 1995 and July 2012. Qualitative as well as quantitative studies were included. Quality was assessed using the Mixed Methods Appraisal Tool. Factors identified were classified as impeding or facilitating, and categorized according to a conceptual framework, an elaborated version of Andersen’s healthcare utilization model. Results Sixteen articles provided relevant factors that were all categorized. A number of factors (migration, culture, position in host country, social network, expertise of the care provider and personal treatment and communication) were found to include both facilitating and impeding factors for non-western women’s utilization of prenatal care. The category demographic, genetic and pregnancy characteristics and the category accessibility of care only included impeding factors. Lack of knowledge of the western healthcare system and poor language proficiency were the most frequently reported impeding factors. Provision of information and care in women’s native languages was the most frequently reported facilitating factor. Conclusion The factors found in this review provide specific indications for identifying non-western women who are at risk of not using prenatal care adequately and for developing interventions and appropriate policy aimed at

  7. Factors affecting the use of prenatal care by non-western women in industrialized western countries: a systematic review.

    Science.gov (United States)

    Boerleider, Agatha W; Wiegers, Therese A; Manniën, Judith; Francke, Anneke L; Devillé, Walter L J M

    2013-03-27

    Despite the potential of prenatal care for addressing many pregnancy complications and concurrent health problems, non-western women in industrialized western countries more often make inadequate use of prenatal care than women from the majority population do. This study aimed to give a systematic review of factors affecting non-western women's use of prenatal care (both medical care and prenatal classes) in industrialized western countries. Eleven databases (PubMed, Embase, PsycINFO, Cochrane, Sociological Abstracts, Web of Science, Women's Studies International, MIDIRS, CINAHL, Scopus and the NIVEL catalogue) were searched for relevant peer-reviewed articles from between 1995 and July 2012. Qualitative as well as quantitative studies were included. Quality was assessed using the Mixed Methods Appraisal Tool. Factors identified were classified as impeding or facilitating, and categorized according to a conceptual framework, an elaborated version of Andersen's healthcare utilization model. Sixteen articles provided relevant factors that were all categorized. A number of factors (migration, culture, position in host country, social network, expertise of the care provider and personal treatment and communication) were found to include both facilitating and impeding factors for non-western women's utilization of prenatal care. The category demographic, genetic and pregnancy characteristics and the category accessibility of care only included impeding factors.Lack of knowledge of the western healthcare system and poor language proficiency were the most frequently reported impeding factors. Provision of information and care in women's native languages was the most frequently reported facilitating factor. The factors found in this review provide specific indications for identifying non-western women who are at risk of not using prenatal care adequately and for developing interventions and appropriate policy aimed at improving their prenatal care utilization.

  8. Does NATO Enlargement Spread Democracy? The Democratic Stabilization of Western Balkan Countries.

    Directory of Open Access Journals (Sweden)

    Zdeněk Kříž

    2012-04-01

    Full Text Available This article deals with NATO enlargement toward Western Balkan countries and tries to answer the question of whether NATO enlargement has contributed to the democratic stabilization of the Western Balkans. The authors conclude that NATO has truly contributed to the democratic stabilization of candidate countries. Nevertheless, we have no evidence supporting the thesis that the democratic stabilization of Albania, Croatia, or Macedonia is progressing solely due to the NATO enlargement policy; it is not clear that NATO is viewed as one of the Western institutions into which these countries want to join. On the one hand, this study shows that NATO enlargement may not have as significant an impact on democratization as has been hoped for by its proponents, who started this process in the mid-90s. On the other hand, the impact of NATO on the consolidation of democratic regimes in candidate countries is by no means zero or even marginal.

  9. Knowledge economy readiness, innovativeness and competitiveness of the Western Balkan countries

    Directory of Open Access Journals (Sweden)

    Cvetanović Slobodan

    2015-01-01

    Full Text Available The Western Balkan countries have set themselves the goal to join the European Union as soon as possible. Accordingly, they must adjust the key components of their development policies to the Europe 2020 strategy, focusing on key priorities such as smart, sustainable and inclusive growth. This paper explores the relationship among knowledge economy readiness, innovativeness, and competitiveness of six Western Balkan countries (Albania, Bosnia and Herzegovina, Macedonia, Serbia, Croatia, and Montenegro and the group of six selected neighboring EU countries (Austria, Bulgaria, Greece, Hungary, Romania, and Slovenia. The paper relies on the data obtained from the Knowledge Economy Index of the World Bank Institute, INSEAD's Global Innovation Index and the Global Competitiveness Index of the World Economic Forum for 2013. Obtained data from all three sources indicated significantly lower readiness for the development of economy based on knowledge, innovation and competitiveness in the Western Balkans countries in comparison to the selected EU countries. The analysis of the interdependence of the aforementioned variables points to: a statistically significant correlation between the indicator knowledge economy index and the global innovation index for both groups of countries; b statistically significant linear correlation between innovativeness and innovation efficiency ratio for the Western Balkan countries. Conversely, no respective correlation has been registered for the group of selected EU countries; c no statistically significant correlation between the global innovation index and the global competitiveness index in the Western Balkan countries, while in respect of the group of selected EU countries, the existence of significant linear correlation between these variables has been revealed.

  10. Assessing variation in tolerance in 23 Muslim-majority and Western countries.

    Science.gov (United States)

    Milligan, Scott; Andersen, Robert; Brym, Robert

    2014-08-01

    Scholars disagree over whether Islam hinders the development of liberal democracy in Muslim-majority countries. We contribute to this debate by assessing the influence of Islam at the individual and national levels on ethnic, racial, and religious tolerance in 23 countries. Our analyses are based on a set of multilevel models fitted to World Values Survey data and national-level contextual information from various sources. Our findings suggest that people living in Muslim-majority countries tend to be less tolerant than are those living in Western countries. Although a significant part of this difference is attributable to variation in level of economic development and income inequality, Muslim countries remain less tolerant even after controlling for these factors. On the other hand, controlling for other individual-level factors, nonpracticing Muslims in Western countries are more tolerant than are all others in both Muslim-majority and Western countries. This finding challenges common claims about the effects of Islam as a religion on tolerance, suggesting that it is Islamic political regimes--not Islam itself--that pose problems for social tolerance.

  11. Performances of hydrated cement treated crushed rock base for Western Australian roads

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    Suphat Chummuneerat

    2014-12-01

    Full Text Available The resilient modulus (RM of hydrated cement treated crushed rock base (HCTCRB affected by amount of hydration periods, compaction and dryback processes was presented using repeated load triaxial tests. The related trends of RM corresponding to the different hydration periods still cannot be concluded. Instead, It is found that the moisture content plays more major influence on the RM performance. Higher additional water during compaction of HCTCRB, even at its optimum moisture content and induced higher dry density, led to the inferior RM performance compared to the sample without water addition. The RM of damper samples can be improved through dryback process and superior to that of the sample without water addition at the same moisture content. However, the samples without water addition during compaction deliver the comparable RM values even its dry density is lower than the other two types. These results indicate the significant influence of moisture content to the performances of HCTCRB with regardless of the dry density. Finally, the experimental results of HCTCRB and parent material are evaluated with the K-θ model and the model recommended by Austroads. These two models provide the excellent fit of the tested results with high degree of determination.

  12. The Participatory Research Approach in Non-Western Countries: Practical Experiences from Central Asia and Zambia

    Science.gov (United States)

    Katsui, Hisayo; Koistinen, Mari

    2008-01-01

    This paper focuses on the application of the participatory research approach in non-Western contexts. The aim is to provide critical insights into the participatory research discourse through an examination of its theory and practice based on our own experiences of using this approach in our doctoral research in five Central Asian countries and…

  13. Modelling Factors of Students' Work in Western Balkan Countries

    Science.gov (United States)

    Savic, Mirko; Kresoja, Milena

    2018-01-01

    The positive side of employment during studies is the increase of net investments in human capital. The main objective of this paper is to discover factors influencing the work of students in Serbia, Bosnia and Herzegovina and Montenegro and to compare students' employment in these three Western Balkan countries. Quantitative analysis based on…

  14. Framing the Iraq war: a cross-national comparison of newspaper framing in four Western countries

    NARCIS (Netherlands)

    Vliegenthart, R.; Schröder, H.

    2010-01-01

    In this paper we compare the newspaper attention for and framing of the Iraq issue in four Western countries (US, UK, Germany and the Netherlands) during the period September 2002 until August 2003. Using computer assisted coding based on wordlists constructed by human coders, we analyzed more than

  15. Peculiarities of Future Finance and Economics Specialists' Training in Western European Countries and Ukraine

    Science.gov (United States)

    Homoniuk, Olena; Pokudina, Larysa

    2016-01-01

    The article touches on the peculiarities of future finance and economics specialists' training in educational establishments of Western Europe and Ukraine. The problem of higher economic education has been considered. The experience of higher economic education organization in developed European countries has been generalized. The peculiarities of…

  16. Tolerance of suicide, religion and suicide rates : an ecological and individual study in 19 Western countries

    NARCIS (Netherlands)

    Neeleman, J; Halpern, D; Leon, D; Lewis, G

    Background. Negative associations between religion and suicide, in individuals and countries, may be mediated by the degree to which suicide is tolerated. Methods. Linear regression was used to examine ecological associations between suicide tolerance, religion and suicide rates in 19 Western

  17. Intercultural Effectiveness Training in three Western immigrant countries : A cross-cultural evaluation of critical incidents

    NARCIS (Netherlands)

    Herfst, Selma L.; van Oudenhoven, Jan Pieter; Timmerman, Marieke E.

    The purpose of the present study is the evaluation of material for a new intercultural training instrument. More specifically, we examine the validity of 21 critical incidents used in the training. The training programme is targeted at natives in Western immigrant countries dealing - mostly

  18. Medicine Availability and Prescribing Policy for Non-Communicable Diseases in the Western Balkan Countries.

    Science.gov (United States)

    Pekez-Pavlisko, Tanja; Racic, Maja; Kusmuk, Srebrenka

    2017-01-01

    During the transition processes, the Western Balkan countries were affected by conflicts and transition-related changes. Life expectancy in these countries is lower, while the mortality from non-communicable diseases (NCDs) is higher in comparison with western and northern parts of Europe. The primary aim of this study was to analyze the treatment possibilities for the most common NCDs in the Western Balkan countries. The secondary aim was to understand and compare the policies regarding prescribing-related competencies of family physicians. In June and July 2017, a document analysis was performed of national positive medicines lists, strategic documents, and clinical guidelines for the treatment of the most frequent NCDs; arterial hypertension, diabetes, hyperlipidemia, asthma, and chronic obstructive pulmonary disease (COPD). All text phrases that referred to medicines prescribing were extracted and sorted into following domains: medicine availability, prescribing policy, and medication prescribing-related competencies. Possibilities for treatment of arterial hypertension, diabetes, hyperlipidemia, asthma, and COPD vary across the Western Balkan countries. This variance is reflected in the number of registered medicines, number of parallels, and number of different combinations, as well as restrictions placed on family physicians in prescribing insulin, inhaled corticosteroids, statins and angiotensin II receptor blockers (ARBs), without consultant's recommendation. Western Balkan countries are capable of providing essential medicines for the treatment of NCDs, with full or partial reimbursement. There are some exceptions, related to statins, newer generation of oral antidiabetic agents and some of the antihypertensive combinations. Prescribing-related competences of family physicians are limited. However, this practice is not compliant to the practices of family medicine, its principles and primary care structures, and may potentially result in increased health

  19. Peculiarities of the Research of the History of Western European Countries, Case of Norway

    Directory of Open Access Journals (Sweden)

    Alexey A. Vorobiev

    2015-01-01

    Full Text Available Abstract: Researcing of history of small advanced countries of Western Europe has a number of specific features, which are connected to its socio-economic level and dynamic development and the dependence on the external economic factor. So the article is devoted to the analysis of regularity of the development of the industry of Norwegian economic specialization (energy sector in the international division of labour as an important element of its historical development. The author of the article analyzes the influence of the energy sector on the political life of the country, the balance of political forces, legislation, foreign policy priorities, and the history of the development of society. At the same time he uses the interdisciplinary approach to determine the relationship of cause and effect between historical events to compile a complete historical picture. The author concludes that the regularities in history are universal and concern all small highly developed countries of Western Europe including Norway. The complex of economic, social, political, financial, legal, tax, environmental and other measures of state support to specialized branches of the national economy is the main semantic rod of historical events in many of the small countries of Western Europe. Analysis of individual industries of the economy in the international division of labor should be an integral part of researches of the historical development of small countries which have a narrow structure of economy, because it helps to understand the peculiarities of the historical development of nations.

  20. Mergers and Acquisitions in the Banking Sector: The Case of Western Balkan Countries / BKT Albania

    Directory of Open Access Journals (Sweden)

    Lulzim Rashiti

    2016-11-01

    Full Text Available This paper aims to explain the financial system which is the engine force for the development of a trade economy. This system ensures payment means in economy and has an impact on its real activity, through the implementation of financial intermediation, acquisitions and mergers in the banking industry that have occurred in recent years in the Western Balkan countries, and monetary policy transmission in these countries. In developing countries, among which are also: Serbia, Macedonia, Albania, Montenegro, etc., banking industry is o" en almost the most important area in the financial system. Therefore, this paper will focus on the way the acquisitions and mergers occurred in the banking system, by assuming that many of the conclusions are applicable to the entire financial system in the Western Balkans. This paper will elaborate on this aspect a case study that deals with the acquisition of Banka Kombetare Tregtare (National Commercial Bank in Albania by the Turkish company Calik Holding (Akif Bank.

  1. The Impact of Tourism on Economic Growth in the Western Balkan Countries: An Empirical Analysis

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    Prof. Dr Nasir Selimi

    2017-06-01

    Full Text Available Purpose: The purpose of this research paper is to empirically analyse the effects of tourism on economic growth in Western Balkan countries (Albania, Bosnia and Herzegovina, Croatia, FYROM, Montenegro and Serbia. Design/Methodology/Approach: The empirical analysis consists of 17-year panel data of 6 countries over the period 1998 to 2014. Several models are analysed using the panel regression econometric techniques. The study investigates the random and fixed effects, as well as individual heterogeneity across those countries. Also, the Hausman Taylor IV estimator is used as the most appropriate model for this analysis. The real income per capita of the sample countries is modelled as dependent on the lagged income per capita, tourist arrivals, tourism receipts, FDI stock, exports and government expenditures. Findings: The estimation results in all types of models, and indicate that tourism has a positive and significant impact on economic growth in the Western Balkan countries. The Hausman Taylor IV model suggests that for every 1% increase of tourist arrivals, the output will increase approximately by 0.08%. Research limitations/implications: Although the Hausman Taylor IV model performs well, the results should be interpreted with caution. The analysis has its limitations; firstly, the total number of observations is relatively small for a panel regression analysis; secondly, the problem of endogenity is not completely avoided. However, the study implies that these countries should enhance efforts for joint tourism sector policies to engender economic sustainability. Originality/Value: To our best knowledge, this is the first attempt of estimating the effects of tourism on economic growth in the Western Balkan countries using the Hausman Taylor IV model.

  2. Physical self-concept of adolescents in Western Balkan countries: a pilot study.

    Science.gov (United States)

    Janić, Snežana Radisavljević; Jurak, Gregor; Milanović, Ivana; Lazarević, Dušanka; Kovač, Marjeta; Novak, Dario

    2014-10-01

    The aim of this study was to explore physical self-concept of adolescents of the Western Balkans (Serbia, Slovenia, Croatia, and Bosnia and Herzegovina) according to sex and country. The participants were 2,606 students, ages 13 and 14 years (M = 13.5, SD = 0.9). The Physical Self-Description Questionnaire (PSDQ) was used to assess multidimensional physical self-concept. The results show the interaction of sex and country for three dimensions of physical self-concept (Appearance, Global Physical Self-Concept, and Self-Esteem). It was shown that female and male adolescents' perception of physical appearance, self-esteem, and global physical self-concept is more susceptible to influences of socio-cultural factors in the monitored countries. In all other dimensions of Physical self-concept, sex differences were consistently manifested in favour of male adolescents, except in Flexibility. Regardless of adolescents' sex, under the increasing influence of Western culture in the Western Balkan countries, adolescents more critically evaluate their body and motor abilities.

  3. DOCTRINAL AND IDEOLOGICAL PARADIGM OF THE CONSERVATISM IN THE WESTERN EUROPEAN COUNTRIES

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    Nikola Gjorshoski

    2015-04-01

    Full Text Available This paper is an illustration of certain specifications in the conservative discourse in a certain European western countries. Each one of the countries from the western hemisphere has its particular peculiarities that determine the usage of the political operation by the conservative parties. Certainly, the complexity of the conservative ideology study has been enriching with the perception of the most basic practices in the political activity of the right parties in some western countries. This paper consists of a short definition about the conservatism followed by its primary and secondary principles. Then, continues to an individual cases in a three highly developed European countries where as a sample are taken the most significant parties in the conservative and Christian Democrat ideology. The conservatism as a political ideology has been formed in the middle of the XVII century as a resistance towards the shifts and the challenges that were under influence of the enlightenment, industrialization and the urbanization. If the conservatism as a political theory, ideology and practice originates from the countries with foregoing activities, logically emerges a need to study their characteristics. The author’s intention is to represent the traits creating the content of that ideology and activity, what are the distinction marks that would be the most appealing of the certain country, as well as to prove the link with the parties from the conservative family on a European level. The study of the conservatism as a political ideology in the modern ideological- doctrinal spectrum would be certainly impossible if there is no closer look to those paradigms.

  4. Sample selection and bribing behaviour: Evidence from post-socialist countries and Western Europe

    OpenAIRE

    Ivlevs, A.; Hinks, T.

    2015-01-01

    We study the individual-level determinants of bribing public officials. Particular attention is paid to the issue of respondents’ non-random selection into contact with public officials, which may result in biased estimates. Data come from the 2010 Life in Transition Survey, covering 30 post-socialist and five Western European countries. The results suggest that the elderly tend to be less likely to bribe public officials, while people with higher income and, especially, low trust in public i...

  5. Dietary Heterogeneity among Western Industrialized Countries Reflected in the Stable Isotope Ratios of Human Hair

    OpenAIRE

    Valenzuela, Luciano O.; Chesson, Lesley A.; Bowen, Gabriel J.; Cerling, Thure E.; Ehleringer, James R.

    2012-01-01

    Although the globalization of food production is often assumed to result in a homogenization of consumption patterns with a convergence towards a Western style diet, the resources used to make global food products may still be locally produced (glocalization). Stable isotope ratios of human hair can quantify the extent to which residents of industrialized nations have converged on a standardized diet or whether there is persistent heterogeneity and glocalization among countries as a result of...

  6. Labour Market Institutions in the Western Balkan Countries and their Economic Implications: Evidence for Kosova

    Directory of Open Access Journals (Sweden)

    MSc. Anera Alishani

    2013-12-01

    To address this issue, this paper provides a literature review of the notion of flexicurity and then investigates the relevance of flexicurity for the countries of the Western Balkans through its found components (flexible and reliable contractual arrangements, lifelong learning, active employment policies and social security system. Even though flexicurity can be a way out for low performed economies it is considered as highly costly.

  7. SUSPECTED CHILD ABUSE: UNUSUAL DEATH IN WESTERN COUNTRY. SUICIDE OR HOMICIDE?

    Directory of Open Access Journals (Sweden)

    Letizia Averna

    2012-03-01

    Full Text Available This case report describes a particular case of carbonized corpse, found in his burnt-out car in an isolated Palermo’s west suburban zone. The goal of this case report is to describe the shame and the social stigma related with suspicious of pedophilia and how it led a man to suicide by fire, considering that is an unusual way to die in western countries.

  8. International cooperation in basic space science, Western Asian countries and the world

    Science.gov (United States)

    de Morais Mendonca Teles, Antonio

    The world will never better develop and attain a global peace state, if it does not exist a world-wide cooperation, union of interests among all countries on planet Earth, respecting and understanding each other culture differences. So, if the countries interested in space science want to create or better develop this field, they need to firstly construct peace states and social cooperation, while scientific and technological cooperation will develop -among them. Here in this paper, under the principles in the United Nations (UN)' Agenda 21 (UN UNCED, 1992), I propose four points that can lead to a practical and solid international cooperation in basic aerospace science and technology, based on ground studies, with sustainable space programs in countries with social necessities, and to the construction of an avenue of peace states in those areas and in the world, 1) The creation of LINKS among the "developing" countries, among the "developed" ones and between them -with scientists, engineers, educators and administrative personnel. This can catalyze a self-sustainable scientific and technological production in the "developing" countries. Financial matters could be done through the World Bank in coopera-tion with UNESCO. 2) The administration of this difficult enterprise of international coopera-tion. With the increasing complexity of relationships among the aerospace-interested countries, it will be necessary the creation of a center capable to serve as an INTERNATIONAL CO-ORDINATOR CENTER FOR AEROSPACE ACTIVITIES. 3) CULTURE: in Western Asian countries there is a cultural habit that when somebody gives something valuable to a person, this person should give something back. Thus, the Western Asian countries receiving infor-mation on basic aerospace science and technology from the "developed" ones, those countries would probably feel they should give something in return. Western Asian countries could trans-mit their costumes, thinking ways, habits, persons' worries

  9. The contribution of tourism industry on the GDP growth of Western Balkan countries

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    Čerović Slobodan

    2015-01-01

    Full Text Available Tourism industry records various economic, social, political and others influences and provides itself important position in the overall economic development of many countries. The analysis of the available data of tourist arrivals and number of tourist overnight stays in observed countries of the Western Balkans (Serbia, Macedonia, Montenegro led us to conduct research in order to determine tourism contribution to the overall economic growth. Based on the modified methodology used by Brida et al. (2008 for calculating real GDP growth rates and tourism contribution to the overall economic growth, the paper indicates that tourism makes a modest direct contribution to the overall economic growth in the examined countries, regardless of the continuous increase in the number of foreign tourist arrivals. The level of tourism contribution to the overall economic growth varies and it is primarily related to diversity and quality of supply (the highest contribution is recorded in Montenegro, while lowest contribution is observed in Macedonia.

  10. Improving estimates of the prevalence of Female Genital Mutilation/Cutting among migrants in Western countries

    Directory of Open Access Journals (Sweden)

    Livia Elisa Ortensi

    2015-02-01

    Full Text Available Background: Female Genital Mutilation/Cutting (FGM/C is an emerging topic in immigrant countries as a consequence of the increasing proportion of African women in overseas communities. Objective: While the prevalence of FGM/C is routinely measured in practicing countries, the prevalence of the phenomenon in western countries is substantially unknown, as no standardized methods exist yet for immigrant countries. The aim of this paper is to present an improved method of indirect estimation of the prevalence of FGM/C among first generation migrants based on a migrant selection hypothesis. A criterion to assess reliability of indirect estimates is also provided. Methods: The method is based on data from Demographic Health Surveys (DHS and Multiple Indicator Cluster Surveys (MICS. Migrants' Selection Hypothesis is used to correct national prevalence estimates and obtain an improved estimation of prevalence among overseas communities. Results: The application of the selection hypothesis modifies national estimates, usually predicting a lower occurrence of FGM/C among immigrants than in their respective practicing countries. A comparison of direct and indirect estimations confirms that the method correctly predicts the direction of the variation in the expected prevalence and satisfactorily approximates direct estimates. Conclusions: Given its wide applicability, this method would be a useful instrument to estimate FGM/C occurrence among first generation immigrants and provide corresponding support for policies in countries where information from ad hoc surveys is unavailable.

  11. Dietary intake and habits of South Asian immigrants living in Western countries.

    Science.gov (United States)

    LeCroy, Madison N; Stevens, June

    2017-06-01

    Previous reviews have indicated that immigration from South Asian to Western countries leads to unhealthy changes in diet; however, these reviews have been limited by the methods used in some included studies. This critical narrative review summarizes findings from original research articles that performed appropriate statistical analyses on diet data obtained using culturally appropriate diet assessment measures. All studies quantitatively compared the diets of South Asian immigrants with those of residents of Western or South Asian countries or with those of South Asian immigrants who had varying periods of time since immigration. Most studies examined total energy and nutrient intake among adults. Total energy intake tended to decrease with increasing duration of residence and immigrant generation, and immigrants consumed less protein and monounsaturated fat compared with Westerners. However, findings for intakes of carbohydrate, total fat, saturated fat, polyunsaturated fat, and micronutrients were mixed. Studies that examine food group intake and include South Asians living in South Asia as a comparison population are needed. © The Author(s) 2017. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  12. Dietary heterogeneity among Western industrialized countries reflected in the stable isotope ratios of human hair.

    Directory of Open Access Journals (Sweden)

    Luciano O Valenzuela

    Full Text Available Although the globalization of food production is often assumed to result in a homogenization of consumption patterns with a convergence towards a Western style diet, the resources used to make global food products may still be locally produced (glocalization. Stable isotope ratios of human hair can quantify the extent to which residents of industrialized nations have converged on a standardized diet or whether there is persistent heterogeneity and glocalization among countries as a result of different dietary patterns and the use of local food products. Here we report isotopic differences among carbon, nitrogen and sulfur isotope ratios of human hair collected in thirteen Western European countries and in the USA. European hair samples had significantly lower δ(13C values (-22.7 to -18.3‰, and significantly higher δ(15N (7.8 to 10.3‰ and δ(34S (4.8 to 8.3‰ values than samples from the USA (δ(13C: -21.9 to -15.0‰, δ(15N: 6.7 to 9.9‰, δ(34S: -1.2 to 9.9‰. Within Europe, we detected differences in hair δ(13C and δ(34S values among countries and covariation of isotope ratios with latitude and longitude. This geographic structuring of isotopic data suggests heterogeneity in the food resources used by citizens of industrialized nations and supports the presence of different dietary patterns within Western Europe despite globalization trends. Here we showed the potential of stable isotope analysis as a population-wide tool for dietary screening, particularly as a complement of dietary surveys, that can provide additional information on assimilated macronutrients and independent verification of data obtained by those self-reporting instruments.

  13. The Impact of Foreign Direct Investment on the Export Performance: Empirical Evidence for Western Balkan Countries

    Directory of Open Access Journals (Sweden)

    Dr.Sc. Nasir Selimi

    2016-07-01

    Full Text Available Recently there are many authors that have studied and analyzed the impact of foreign direct investments (FDI on the export performance. They have different opinions about the effect of foreign direct investments on the export performance. Some of them in their papers conclude that FDI have positive effect on the export performance and some not. There are also findings that FDI do not have any impact on the export performance. Of course for economic benefit of host country it is not important only the amount of FDI, but also their structure. To measure the effect of FDI on the export performance is not easy. Therefore, the main objective of this paper is to analyze empirically the foreign direct investments and exports performance during the period of 1996-2013 in Western Balkan countries. The paper also investigates for the fixed effects and individual heterogeneity across countries and years. Based on the panel regression techniques and Least Square Dummy Variable (LSDV regression method, FDI positively affect export performance in the sample countries in various model specifications. The results and conclusions of this paper we hope that will help everybody who are interested and studying this matter, especially the policy makers.  The last ones have the obligation to facilitate and promote the export if they award confirm that FDI contribute on developing their economy.

  14. Naso-ethmoidal encephalocele with bilateral orbital extension: report of a case in a western country.

    Science.gov (United States)

    Secci, Francesca; Consales, Alessandro; Merciadri, Paolo; Ravegnani, Giuseppe Marcello; Piatelli, Gianluca; Pavanello, Marco; Cama, Armando

    2013-10-01

    Encephalocele is a rare congenital malformation of the central nervous system with protrusion of cranial content (meninges, brain, and ventricles in different combinations) beyond the normal confines of the skull. Anterior encephaloceles occur with a high frequency in Southeast Asia, while in the Western countries occipital encephaloceles prevail. The treatment of an anterior (naso-ethmoidal) encephalocele involves a neurosurgeon or a multidisciplinary team (neurosurgeon, maxillofacial surgeon, plastic surgeon, and ENT surgeon) dealing with craniofacial surgery. Goals of surgery include removal or repositioning of nonfunctional cerebral tissue, closure of the dura, and reconstruction of skeletal and cutaneous structures. The prognosis depends from the anatomical site, volume of neural contents, and the presence of coexisting malformations. We report the case of an Italian child suffering from a naso-ethmoidal encephalocele with bilateral orbital extension. The surgical treatment was performed in two steps. Sincipital encephalocele is a complex pathology without a unique standardized surgical treatment. Its low incidence in Western countries can make its management particularly tricky.

  15. Impact of unemployment variations on suicide mortality in Western European countries (2000-2010).

    Science.gov (United States)

    Laanani, Moussa; Ghosn, Walid; Jougla, Eric; Rey, Grégoire

    2015-02-01

    A scientific debate is currently taking place on whether the 2008 economic crisis caused an increase in suicide rates. Our main objective was to assess the impact of unemployment rate on suicide rate in Western European countries between 2000 and 2010. We then tried to estimate the excess number of suicides attributable to the increase of unemployment during the 2008-2010 economic crisis. The yearly suicide rates were modelled using a quasi-Poisson model, controlling for sex, age, country and a linear time trend. For each country, the unemployment-suicide association was assessed, and the excess number of suicides attributable to the increase of unemployment was estimated. Sensitivity analyses were performed, notably in order to evaluate whether the unemployment-suicide association found was biased by a confounding context effect ('crisis effect'). A significant 0.3% overall increase in suicide rate for a 10% increase in unemployment rate (95% CI 0.1% to 0.5%) was highlighted. This association was significant in three countries: 0.7% (95% CI 0.0% to 1.4%) in the Netherlands, 1.0% (95% CI 0.2% to 1.8%) in the UK and 1.9% (95% CI 0.8% to 2.9%) in France, with a significant excess number of suicides attributable to unemployment variations between 2008 and 2010 (respectively 57, 456 and 564). The association was modified inconsistently when adding a 'crisis effect' into the model. Unemployment and suicide rates are globally statistically associated in the investigated countries. However, this association is weak, and its amplitude and sensitivity to the 'crisis effect' vary across countries. This inconsistency provides arguments against its causal interpretation. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  16. Experience of Forming Professional and Communicative Competency of Future Social Workers in Education Systems of Western European Countries

    Science.gov (United States)

    Baranyuk, Vita

    2015-01-01

    The article analyzes the experience of forming professional and communicative competency of future social workers in the education systems of Western European countries, in particular, France, Germany and Switzerland. On the basis of generalization of the studied data it has been found out that each country has its own techniques of forming…

  17. Mingadhuga Mingayung: Respecting Country through Mother Mountain's Stories to Share Her Cultural Voice in Western Academic Structures

    Science.gov (United States)

    McKnight, Anthony

    2015-01-01

    The cultural invasion of Yuin Country in Australia not only colonized the Yuin people and Yuin Country itself, but also contributed to non-Aboriginal people's continual colonized journey of disconnecting self from Mother Earth. Cultural awareness is a process driven by Western theories informed by the colonial dualism that functions on separation…

  18. Integrative review of cervical cancer screening in Western Asian and Middle Eastern Arab countries.

    Science.gov (United States)

    Ali, Suhailah; Skirton, Heather; Clark, Maria T; Donaldson, Craig

    2017-12-01

    Population-based screening programs have resulted in minimizing mortality and morbidity from cervical cancer. The aim of this integrative review was to explore the factors influencing access of women from Western Asian and Middle Eastern Arab countries to cervical cancer screening. A systematic search for studies conducted in Arab countries in those regions, and published in English between January 2002 and January 2017, was undertaken. Thirteen papers were selected and subjected to quality appraisal. A three step analysis was used, which involved a summary of the evidence, analysis of both quantitative and qualitative data, and integration of the results in narrative form. Few population-based cervical cancer screening programs had been implemented in the relevant countries, with low knowledge of, and perceptions about, cervical screening among Arab women, the majority of whom are Muslim. Factors affecting the uptake of cervical cancer screening practices were the absence of organized, systematic programs, low screening knowledge among women, healthcare professionals' attitudes toward screening, pain and embarrassment, stigma, and sociocultural beliefs. Policy changes are urgently needed to promote population-based screening programs. Future research should address the promotion of culturally-sensitive strategies to enable better access of Arab Muslim women to cervical cancer screening. © 2017 John Wiley & Sons Australia, Ltd.

  19. Factors associated with smoking in immigrants from non-western to western countries - what role does acculturation play? A systematic review.

    Science.gov (United States)

    Reiss, Katharina; Lehnhardt, Jessica; Razum, Oliver

    2015-01-01

    We aimed to identify factors associated with smoking among immigrants. In particular, we investigated the relationship between acculturation and smoking, taking into consideration the stage of the 'smoking epidemic' in the countries of origin and host countries of the immigrants. We searched PubMed for peer-reviewed quantitative studies. Studies were included if they focused on smoking among adult immigrants (foreign-born) from non-western countries now residing in the USA, Canada, Ireland, Germany, the Netherlands, Norway, the UK, and Australia. Studies were excluded if, among others, a distinction between immigrants and their (native-born) offspring was not made. We retrieved 27 studies published between 1998 and 2013. 21 of the 27 studies focused on acculturation (using bidimensional multi-item scales particularly designed for the immigrant group under study and/or proxy measures such as language proficiency or length of stay in host country) and 16 of those found clear differences between men and women: whereas more acculturated women were more likely to smoke than less acculturated women, the contrary was observed among men. Immigrants' countries of origin and host countries have reached different stages of the 'smoking epidemic' where, in addition, smoking among women lags behind that in men. Immigrants might 'move' between the stages as (I) the (non-western) countries of origin tend to be in the early phase, (II) the (western) host countries more in the advanced phase of the epidemic and (III) the arrival in the host countries initiates the acculturation process. This could explain the 'imported' high (men)/low (women) prevalence among less acculturated immigrants. The low (men)/high (women) prevalence among more acculturated immigrants indicates an adaptation towards the social norms of the host countries with ongoing acculturation.

  20. Risk factors for acute care hospital readmission in older persons in Western countries

    DEFF Research Database (Denmark)

    Pedersen, Mona Kyndi; Meyer, Gabriele; Uhrenfeldt, Lisbeth

    2017-01-01

    BACKGROUND: Hospital readmission in older persons is common and reported as a post-discharge adverse outcome from hospitalization. Readmission relates to a mix of factors associated with increasing age, living conditions, progression of disease as well as factors related to the processes of care...... extracted verbatim using a data extraction form, which identified the components from the standardized JBI data extraction tool from JBI-MAStARI and was adapted to the needs of the present review. DATA SYNTHESIS: Due to the clinical and methodological heterogeneity of the studies included, a narrative...... summary and metasynthesis of the quantitative findings was conducted. RESULTS: Based on a review of nine studies from ten Western countries, we found several significant risk factors pertaining to readmission to an acute care hospital within one month of discharge in persons aged 65 years and over...

  1. Attitudes of medical school deans toward interprofessional education in Western Pacific Region countries.

    Science.gov (United States)

    Lee, Bumsuk; Celletti, Francesca; Makino, Takatoshi; Matsui, Hiroki; Watanabe, Hideomi

    2012-11-01

    To examine the attitudes of medical school deans toward interprofessional education (IPE) and collaborative practice (CP), we conducted survey research in the Western Pacific Region. This regional survey was conducted as a collaborative research project with the World Health Organization. A survey was distributed to the medical school deans in Malaysia, the Philippines, Republic of Korea and Japan. Thirty-five surveys were returned from four countries. The survey demonstrated that many medical school deans have positive attitudes toward IPE and CP. However, respondents also reported that it is not easy to introduce interprofessional learning in their academic settings. It is suggested that collaboration between education systems and health systems is needed to introduce IPE in the academic setting. The possible role of international organizations is mentioned. This information helps to identify local efforts on which global health organizations and national governments can build.

  2. Product availability from delivery aspect: Evidence from retailers in selected Western Balkan countries

    Directory of Open Access Journals (Sweden)

    Grubor Aleksandar

    2016-01-01

    Full Text Available Bearing in mind that it represents one of the main preconditions of sales, product availability is the key task of retail companies and their delivery systems. This paper analyses its levels from the aspect of centralized and DSD systems. The research is conducted in Serbia, Bosnia and Herzegovina and Montenegro, including 84 stores and more than 70 FMCG products per each store. Thereby, the comparisons in product availability levels between alternative delivery systems are carried out within different trading formats and within different product categories. Unlike the results of similar studies and ongoing changes on retail markets, this research shows that at retailers in these Western Balkan countries, availability levels are higher in the case of DSD system.

  3. Welfare State Regimes and Attitudes Towards Redistribution in 15 Western European Countries

    DEFF Research Database (Denmark)

    Jæger, Mads

    In this paper we analyse how different welfare state regimes affect popular support for redistribution across 15 Western European countries. We suggest that the main reasons why previous studies have not been able to connect welfare state regimes and popular attitudes towards the welfare state...... Social Survey and the third wave of the European Values Study, and by means of an ordered mixed probit model with concomitant variables, we find strong evidence that structural characteristics affect mass opinion in a manner consistent with regime theory. For example, public support for redistribution...... at: http://www.sfi.dk/s%c3%b8geresultat-10668.aspx?Action=1&NewsId=248&PID=32427#sthash.ISdYS6vF.dpuf...

  4. Electricity pricing as a demand-side management strategy: Western lessons for developing countries

    Energy Technology Data Exchange (ETDEWEB)

    Hill, L.J.

    1990-12-01

    Electric utilities in the Western world have increasingly realized that load commitments can be met not only by constructing new generating plants but also by influencing electricity demand. This demand-side management (DSM) process requires that electric utilities promote measures on the customer's side of the meter to directly or indirectly influence electricity consumption to meet desired load objectives. An important demand-side option to achieve these load objectives is innovative electricity pricing, both by itself and as a financial incentive for other demand-site measures. This study explores electricity pricing as a DSM strategy, addressing four questions in the process: What is the Western experience with DSM in general and electricity pricing in particular Do innovative pricing strategies alter the amount and pattern of electricity consumption Do the benefits of these pricing strategies outweigh the costs of implementation What are future directions in electricity pricing Although DSM can be used to promote increases in electricity consumption for electric utilities with excess capacity as well as to slow demand growth for capacity-short utilities, emphasis here is placed on the latter. The discussion should be especially useful for electric utilities in developing countries that are exploring alternatives to capacity expansion to meet current and future electric power demand.

  5. The Clinical Factors for Predicting Severe Diverticulitis in Korea: A Comparison with Western Countries

    Science.gov (United States)

    Kim, Sun Young; Seo, Ji Young; Jeon, Tae Joo; Seo, Dong Dae; Shin, Won Chang; Choi, Won Choong; Jeong, Myeong Ja

    2012-01-01

    Background/Aims It is unclear whether the risk factors associated with complicated diverticulitis in Asian and Western countries are the same. We evaluated the risk factors associated with severe diverticulitis (SD) in Korea and compared the clinical characteristics of diverticulitis according to location. Methods A retrospective review of 190 patients hospitalized with acute diverticulitis from January 2005 to June 2010 was conducted. SD was defined as one of the following: perforation, abscess, obstruction, sepsis, or peritonitis that required an urgent operation. Results Twenty-four patients (12.6%) were diagnosed with SD. SD was significantly associated with older age, a fever over 38℃, changes in bowel habits and a high visceral adipose tissue (VAT)/total adipose tissue (TAT) ratio. Multivariate analysis showed that the risk factors for developing SD were an age of 40 years or more (odds ratio [OR], 3.2; p=0.032), male gender (OR, 4.0; p=0.021) and left-sided diverticulitis (OR, 6.2; p=0.017). Right-sided diverticulitis (n=175, 92.1%) was significantly associated with younger ages, fewer changes in bowel habits, fewer comorbidities and non-SD. Conclusions This study suggests that the risk factors for developing SD in Korea, where right-sided diverticulitis is predominant, are the male gender, an age of more than 40 years old, and left-sided diverticulitis. Given that there are different risk factors for developing SD in Western countries, different strategies for the treatment of diverticulitis in the Korean population seem to be needed. PMID:22375175

  6. [Assurance and assessment of quality education in occupational medicine in selected countries of western Europe and in the United States. 1. Western Europe].

    Science.gov (United States)

    Boczkowski, A

    2000-01-01

    The author discusses the studies undertaken with the general aim to provide education in occupational medicine and assure and assess its quality in some countries of Western Europe advanced more than Poland in this area. It becomes quite evident that despite a widespread interest in quality of education, there is a lack of basic systemic solutions. A gap between basic theoretical and methodological guidelines and a large number of dispersed reports on concrete analytical and evaluation studies can be still observed. In addition to the presentation of an inside view of research activities carried out in some countries of Western Europe and the United States, based on selected professional publications, the author formulates general conclusions on how the assurance and quality assessment of education in occupational medicine function in those countries.

  7. Iceland as a western country. How to classify medieval church law in the vernacular

    Directory of Open Access Journals (Sweden)

    Lára Magnúsardóttir

    2015-12-01

    Full Text Available Iceland’s subjection to the king of Norway in 1262-64 was followed by a legislation in which a law book for Church and spiritual matters was composed in the vernacular for each country. Such law was implemented in Iceland in 1275 along with a separate secular law book in 1281. Both books remained in force until the middle of the 16th century. A church law that was separate, both from the secular law and that of Roman Church appears to set Iceland apart from other Western European countries where spiritual matters were governed according to the Latin law of the Roman Church. This has been viewed as an indication of constant rivalry between the religious and secular authorities, usually presenting the Church as an overreaching and even oppressive institution against which laity struggled. But a comparison of Icelandic Church law with the Latin Canon law shows that the Church in Iceland submitted entirely to the authority of the Roman Church and thus shows that the Icelandic Church law was, despite its obscure language, a specific representation of the law of the Roman Church. A Norwegian concordat from 1277 shows the king’s recognition of separate spiritual and temporal jurisdictions. This cooperation is readily apparent in later court cases.

  8. Nurse prescribing of medicines in Western European and Anglo-Saxon countries: a survey on forces, conditions and jurisdictional control

    NARCIS (Netherlands)

    Kroezen, M.; Francke, A.L.; Groenewegen, P.P.; van Dijk, L.

    2012-01-01

    Background: The number of Western European and Anglo-Saxon countries where nurses are legally allowed to prescribe medicines is growing. As the prescribing of medicines has traditionally been the task of the medical profession, nurse prescribing is changing the relationship between the medical and

  9. Nurse prescribing of medicines in Western European and Anglo-Saxon countries: a survey on forces, conditions and jurisdictional control.

    NARCIS (Netherlands)

    Kroezen, M.; Francke, A.L.; Groenewegen, P.P.; Dijk, L. van

    2012-01-01

    Background: The number of Western European and Anglo-Saxon countries where nurses are legally allowed to prescribe medicines is growing. As the prescribing of medicines has traditionally been the task of the medical profession, nurse prescribing is changing the relationship between the medical and

  10. Explaining the gender gap in radical right voting: A cross-national investigation in 12 Western European countries

    NARCIS (Netherlands)

    Immerzeel, Tim; Coffe, Hilde; van der Lippe, Tanja

    2015-01-01

    It is common wisdom in radical right research that men are over-represented among the radical right electorate. We explore whether a radical right gender gap exists across 12 Western European countries and examine how this gap may be explained. Using the European Values Study (2010), we find a

  11. Family-Centered Care As a Western-Centric Model in Developing Countries: Luxury Versus Necessity.

    Science.gov (United States)

    Al-Motlaq, Mohammad A; Shields, Linda

    Family-centered care (FCC) is a model of care that emerged over many years and is broadly defined as promoting a partnership between the parents and health care professionals in the care of the child. Although recognized by many as the ideal way to care for children and families, previous reviews showed a lack of evidence for its efficacy. A recent Cochrane review recommended further rigorous research to assess the model's effect. Other reports emerged to ascertain FCC poor implementation. There is also a paucity of studies investigating the model outside the Western context. This article dissects the literature and provides a comprehensive summary on FCC in the context of limited resources versus best practice. Lessons learned from the literature for the reproducibility of the model in the developing world are provided. Considered a luxury, the autocratic health systems in most of these countries will not easily accept such a model of care except with a greater understanding and support for the model and high-quality research that can guide hospitals, health systems, and policy makers.

  12. Economic analysis of different supporting policies for the production of electrical energy by solar photovoltaics in western European Union countries

    International Nuclear Information System (INIS)

    Dusonchet, Luigi; Telaretti, Enrico

    2010-01-01

    Within various renewable energy technologies, photovoltaics (PV) today attracts considerable attention due to its potential to contribute a major share of renewable energy in the future. However, PV market development is, undoubtedly, dependent on the political support of any given country. In this paper, after a brief analysis of national support policies in PV technology in western European Union (EU) countries, the authors perform an economic analysis of the main support mechanisms as implemented in the same countries, based on the calculation of the cash flow, the Net Present Value (NPV) and the Internal Rate of Return (IRR) indices. The analysis shows that in some situations support policies can be inconvenient for the owner of the PV-based generation system and that, in many cases, the differences between the implementation of the same support policy in different countries, can give rise to significantly different results. The analysis carried out in this work could help: ·to assess the impact of PV energy policies in different western European member states; ·renewable energy companies to identify potential PV markets and investigate the policy landscape across western EU countries.

  13. Determinants of the sustainability of farming on leased agricultural land in Poland in comparison with selected Western European countries

    Directory of Open Access Journals (Sweden)

    Adam Majchrzak

    2014-08-01

    Full Text Available In Western Europe the lease is the dominant form of land management in agriculture. This is not only due to the tradition of this institution, but also to the scope of the regulations that guarantee the stability of the legal relationship and ensure the independence of the lessee in production process based on the subject of the lease. This article attempts to assess the instruments for the protection of farming on leased agricultural land in Poland in comparison with solutions applicable in after countries of Western Europe. In this paper, a review of regulations relating to the length of the lease, the obligation to care for the preservation of the quality of the resource, as well as the criteria for determining the amount of the rent, is examines . On this basis, it has been shown that the regulations determining the stability of the lease in Poland deviate far from the norms provided in most Western European countries. This implies that the legal position of a lessee in Poland is weaker than it is in the rest of Western Europe, which is a negative assessment from point of view the of agrarian structure in Poland.

  14. Geoarchaeological studies of the Yalibirri Mindi rock shelter, Weld Range, Wajarri Yamaji Country, Western Australia

    Science.gov (United States)

    Leopold, Matthias; Brown, Viviene; Carson, Anneliese; D'Ovidio, Belinda; Yusiharni, Emielda; Winton, Vicky

    2017-04-01

    Understanding of past environmental conditions can be used to answer archaeologically based questions. Geoarchives such as soils and sediments inside rockshelters store information about chemical and physical processes from their time of formation thus allowing the reconstruction of the past. This study seeks to understand the sediment and soil formation factors at the 'Yalibirri Mindi' rock shelter, located in the Weld Range in the country of the Wajarri Yamaji Aboriginal people of Mid West Western Australia. The project is part of the 'federally funded Weld Range Web of Knowledge Project' . The aim of the work is to evaluate the origin of dated carbon material and associated sediments. Rockshelter sediments as well as two soil profiles outside the shelter were characterized using a series of different laboratory techniques such as pH and EC, nested particle sieving, ICP-OES, XRD, XRF, CN and radiocarbon analysis as well as magnetic susceptibility. An additional heating experiment was performed to simulate the influence of frequent fire on the magnetic properties of the sediments to evaluate potential anthropogenic origin of fire remains (charcoal). Pleistocene age estimates were obtained for some of the charcoal found in association with Aboriginal flaked stone artefacts. The lowest layer containing Aboriginal artefacts was dated to 29,089 ± 132 years uncal. BP providing the first evidence for Pre-Last Glacial Maximum occupation of the inland Mid West in Australia. Sediment analyses indicate that the rockshelter sediments are the result of in-situ weathering with contemporaneous human occupation rather than transport from outside. Gypsum (CaSO4.2H2O), which is not part of the natural environment in the surrounding area was identified in the rockshelter sediments and might be indicative of heating and evaporation during wood fire burning. Human induced fires had also altered the magnetic susceptibility of the sediments. Sedimentological analyses strongly support

  15. Comparison of perceived barriers to entrepreneurship in Eastern and Western European countries

    NARCIS (Netherlands)

    Iakovleva, T.A.; Kolvereid, L.; M.J. Gorgievski-Duijvesteijn (Marjan); Sørhaug, Ø

    2014-01-01

    textabstractThis qualitative study among 591 business students from four European countries investigated cross-country differences in the kind of barriers people perceive to business start-up. In line with institutional theory, the most important perceived barriers in all countries related to

  16. Emergence in Western African Countries of MDR-TB, Focus on Côte d’Ivoire

    Directory of Open Access Journals (Sweden)

    Euloge Ekaza

    2013-01-01

    Full Text Available Tuberculosis (TB is responsible for a high mortality rate (2.5% worldwide, mainly in developing countries with a high prevalence of human immunodeficiency virus (HIV. The emergence of multiresistant strains of TB poses an extreme risk for TB outbreaks and highlights the need for global TB control strategies. Among Western African countries, Côte d’Ivoire (CI represents a specific example of a country with great potential to prevent TB. Specifically, CI has a promising healthcare system for monitoring diseases, including vaccination programs. However, military and political conflict in CI favors the spread of infectious diseases, TB being among the most devastating. Compilation of the studies identifying common causes of TB would be extremely beneficial for the development of treatment and prevention strategies. Therefore, the purpose of this comprehensive review is to evaluate the epidemiology of TB in CI, describe the factors involved in pathogenesis, and suggest simple and applicable prevention strategies.

  17. Cement Formation

    DEFF Research Database (Denmark)

    Telschow, Samira; Jappe Frandsen, Flemming; Theisen, Kirsten

    2012-01-01

    Cement production has been subject to several technological changes, each of which requires detailed knowledge about the high multiplicity of processes, especially the high temperature process involved in the rotary kiln. This article gives an introduction to the topic of cement, including...... an overview of cement production, selected cement properties, and clinker phase relations. An extended summary of laboratory-scale investigations on clinkerization reactions, the most important reactions in cement production, is provided. Clinker formations by solid state reactions, solid−liquid and liquid...

  18. Class voting in Western industrialized countries, 1945-1990: Systematizing and testing explanations

    NARCIS (Netherlands)

    Nieuwbeerta, P.; Ultee, W.C.

    1999-01-01

    Analyzing data obtained from the literature and our own calculations, significant differences were found among countries in their levels of class voting. The Scandinavian countries had the highest and Canada and the USA the lowest levels of class voting. Since the 1950s, there was a decline in

  19. East Asian's Perception of Western Countries' Urban Hygiene and Public Health in the Late Nineteenth Century: A Review Article.

    Science.gov (United States)

    Min, You-Ki; Park, Sam-Hun

    2017-10-01

    Modern hygiene administration in Japan and Korea began to be organized in the end of 19th Century by accepting Western public health system. Then, how did the elite in these two East Asian countries recognize and understand Western public health movement in the 19th Century? Answering this question could provide historical knowledge about the background of starting modern hygiene administration in East Asia. To understand the birth of modern public health system in East Asia, Japanese and Korean elite's records on Western countries were reviewed. The documents examined were The Iwakura Embassy 1871-73 published in 1878 as an account of Japanese Meiji government's special ambassador sent to the United States and Europe, and Seoyugyeonmun (observations on travels in the West) published in 1895 by a Korean intelligent. The Iwakura Embassy 1871-73 suggested modern water supply and drainage, roadside trees, and parks, to prevent contagious diseases and improve urban hygiene. Seoyugyeonmun emphasizes that hygiene is an important task that civilized government has to be in charge. So, specific tasks of public health should be imposed on sanitary police. Public health was one of the major factors that contributed to national prosperity in the 19th century. Such recognition enabled organization of hygiene administration to be part of the project pursuing enlightenment, modernization, and civilization at the end of the 19th century in Japan and Korea.

  20. Petrologic and stable isotopic studies of a fossil hydrothermal system in ultramafic environment (Chenaillet ophicalcites, Western Alps, France): Processes of carbonate cementation

    Science.gov (United States)

    Lafay, Romain; Baumgartner, Lukas P.; Stephane, Schwartz; Suzanne, Picazo; German, Montes-Hernandez; Torsten, Vennemann

    2017-12-01

    The Late Jurassic Chenaillet ophiolitic complex (Western Alps) represents parts of an oceanic core-complex of the Liguria-Piemonte domain. A model for the origin and evolution of the Chenaillet ophicalcites based on textural and isotopic characterization is presented. The Chenaillet ophicalcites correspond to brecciated serpentinized peridotites that record seafloor shallow serpentinization at a minimum temperatures of 150 °C followed by authigenic carbonation. Carbonation starts with a network of micrometric to millimetric pre- or syn-clast formation calcite veins accompanied by a pervasive carbonation of residual olivine and serpentine inside the serpentinite mesh core. A matrix of small calcite (values that range between - 5‰ and + 0.4‰. The lower values were obtained for calcite within the serpentinite clasts. The δ18O (VSMOW) values have a range between + 11‰ and + 16‰ in carbonated clasts. The δ18O values in the matrix are fairly homogeneous with an average at + 12‰ and the late calcite veins have values between + 12.5 and + 15.5‰. These values suggest a relatively high temperature of formation for all the carbonates. Carbonates within clast are mainly characterized by a formation temperature in the range of 110 °C to 180 °C assuming a δ18O value of seawater of 0‰, the matrix forms at a temperature of ca. 165 °C. Late veins are characterized by a formation temperature ranging between 120and 155 °C. We propose a model where serpentinization is followed by discrete carbonation then brecciation and cementation as a consequence of continuous hydrothermal fluid circulation in the serpentinite basement. This is comparable to observations made in the stockwork of present-day long-lived oceanic hydrothermal systems.

  1. Population thiamine status and varying cancer rates between western, Asian and African countries.

    Science.gov (United States)

    Boros, L G

    2000-01-01

    The role of food supplements in the form of vitamins has not been extensively investigated in relation to varying cancer rates between populations of different geographical regions. New data indicate that thiamine (vitamin B1), a common food supplement in Western food products, is directly involved in nucleic acid ribose synthesis of tumor cells in its biologically activated form through the non-oxidative transketolase catalyzed pentose cycle reaction. Whether thiamine plays a role in increased cancer rates in the Western World by enhancing tumor cell proliferation, while increased consumption of thiaminase rich food limiting thiamine availability protects against common malignancies in Asia and Africa has not been evaluated. In the Western World, thiamine is a popular vitamin supplement in the form of tablets and it is also added to basic food items such as milled flour, cereals, peanut butter, refreshment drinks and pastas. On the contrary, thiaminase, the natural thiamine-degrading enzyme, is abundantly present in raw and fermented fish, certain vegetables and roasted insects consumed primarily in Africa and Asia. Excess thiamine supplementation in common food products may contribute to the increased cancer rates of the Western World.

  2. From Tegucigalpa to Teheran: Brazil's diplomacy as an emerging Western country

    Directory of Open Access Journals (Sweden)

    Andrea Quirino Steiner

    2014-01-01

    Full Text Available This paper reviews Brazil's pursuit for international insertion by: discussing its search for new partners; presenting an overview of the historical, cultural, and political features that render it the most Western of the emerging nations; and analyzing its participation in the management of two major international crises, the Honduran constitutional crisis and the Iranian nuclear crisis.

  3. Nurse prescribing of medicines in Western European and Anglo-Saxon countries: a systematic review of the literature.

    Science.gov (United States)

    Kroezen, Marieke; van Dijk, Liset; Groenewegen, Peter P; Francke, Anneke L

    2011-05-27

    A growing number of countries are introducing some form of nurse prescribing. However, international reviews concerning nurse prescribing are scarce and lack a systematic and theoretical approach. The aim of this review was twofold: firstly, to gain insight into the scientific and professional literature describing the extent to and the ways in which nurse prescribing has been realised or is being introduced in Western European and Anglo-Saxon countries; secondly, to identify possible mechanisms underlying the introduction and organisation of nurse prescribing on the basis of Abbott's theory on the division of professional labor. A comprehensive search of six literature databases and seven websites was performed without any limitation as to date of publication, language or country. Additionally, experts in the field of nurse prescribing were consulted. A three stage inclusion process, consisting of initial sifting, more detailed selection and checking full-text publications, was performed independently by pairs of reviewers. Data were synthesized using narrative and tabular methods. One hundred and twenty-four publications met the inclusion criteria. So far, seven Western European and Anglo-Saxon countries have implemented nurse prescribing of medicines, viz., Australia, Canada, Ireland, New Zealand, Sweden, the UK and the USA. The Netherlands and Spain are in the process of introducing nurse prescribing. A diversity of external and internal forces has led to the introduction of nurse prescribing internationally. The legal, educational and organizational conditions under which nurses prescribe medicines vary considerably between countries; from situations where nurses prescribe independently to situations in which prescribing by nurses is only allowed under strict conditions and supervision of physicians. Differences between countries are reflected in the jurisdictional settlements between the nursing and medical professions concerning prescribing. In some

  4. Nurse prescribing of medicines in Western European and Anglo-Saxon countries: a systematic review of the literature

    Directory of Open Access Journals (Sweden)

    Groenewegen Peter P

    2011-05-01

    Full Text Available Abstract Background A growing number of countries are introducing some form of nurse prescribing. However, international reviews concerning nurse prescribing are scarce and lack a systematic and theoretical approach. The aim of this review was twofold: firstly, to gain insight into the scientific and professional literature describing the extent to and the ways in which nurse prescribing has been realised or is being introduced in Western European and Anglo-Saxon countries; secondly, to identify possible mechanisms underlying the introduction and organisation of nurse prescribing on the basis of Abbott's theory on the division of professional labor. Methods A comprehensive search of six literature databases and seven websites was performed without any limitation as to date of publication, language or country. Additionally, experts in the field of nurse prescribing were consulted. A three stage inclusion process, consisting of initial sifting, more detailed selection and checking full-text publications, was performed independently by pairs of reviewers. Data were synthesized using narrative and tabular methods. Results One hundred and twenty-four publications met the inclusion criteria. So far, seven Western European and Anglo-Saxon countries have implemented nurse prescribing of medicines, viz., Australia, Canada, Ireland, New Zealand, Sweden, the UK and the USA. The Netherlands and Spain are in the process of introducing nurse prescribing. A diversity of external and internal forces has led to the introduction of nurse prescribing internationally. The legal, educational and organizational conditions under which nurses prescribe medicines vary considerably between countries; from situations where nurses prescribe independently to situations in which prescribing by nurses is only allowed under strict conditions and supervision of physicians. Conclusions Differences between countries are reflected in the jurisdictional settlements between the

  5. Cementing of low pressure formations

    Energy Technology Data Exchange (ETDEWEB)

    Brownlie, D. [Trican Well Service Ltd., Calgary, AB (Canada); Coupland, M. [Baytex Energy Ltd., Calgary, AB (Canada)

    2001-07-01

    This paper proposed a solution to the notorious problem of squeeze cementing low pressure formations. It is a well known fact within the petroleum industry that it is difficult to squeeze cement low pressure formations in certain areas. Short of fracturing, most geological formations will not allow cement to penetrate the actual rock. In standard cement squeezing, cement slurries are placed across perforations and then pressure is applied to force the cement into perforation tunnels against the formation causing partial dehydration of the slurry. The cement left in the perforation tunnels makes a seal between the formation and the wellbore that has high compressive strength and low permeability. However, experience has shown that some wells are not capable of holding the hydrostatic pressure of a water column. This paper presented case studies that examined formations with modified geology, a highly unconsolidated sandstone where large volumes of sand were extracted during the production process. In particular, the paper refers to a low pressure field in Western Canada, the remedial cementing in Lloydminster. Within a 3 year period 18 zones were cement squeezed and drilled out. Nine of the zones were cement squeezed using a retainer with thixotropic cement followed by a 0:1:0 Class G cement. Only 11 per cent of the 9 zones was successful on the first attempt. The other 9 zones were cement squeezed using the bullhead technique in which a fluid is shot into the well casing before the downhole equipment. This latter technique proved to be more successful on the first attempt. 2 refs.

  6. Pharmacological treatment for attention deficit hyperactivity disorder: functional outcomes in children and adolescents from non-Western countries

    Directory of Open Access Journals (Sweden)

    Murat Altin

    2013-09-01

    Full Text Available Objective: Functional outcomes were measured over a 12-month period in children and adolescents with attention deficit hyperactivity disorder (ADHD after they received monotherapy. Design: Prospective, observational, noninterventional study. Setting: Conducted in six non-Western countries. Participants: Outpatients 6 to 17 years of age with a verified diagnosis of ADHD in accordance with the Diagnostic and Statistical Manual, Fourth Edition, Text Revision (DSM-IV-TR, together with their physicians, decided to initiate or switch treatment for ADHD. Patients were prescribed pharmacological monotherapy: methylphenidate (n=221, nootropic agents (n=91, or atomoxetine (n=234. Measurements: Patients were followed for changes in their functional status and quality of life, which were assessed with the Child Health and Illness Profile–Child Edition (CHIPCE Achievement domain. Results: At the end of the study, a mean improvement on the CHIP-CE Achievement domain score was observed for all countries and therapies except in Taiwan, where patients received atomoxetine, and in Lebanon, where patients received methylphenidate. No patient experienced a serious adverse event during the study. Four patients discontinued due to a treatment-emergent adverse event. Conclusion: After 12 months of treatment, clinical and functional outcomes were improved in children and adolescents from non-Western countries who initiated and remained on their prescribed pharmacological monotherapy.

  7. Contextual explanations for numeracy and literacy skill disparities between native and foreign-born adults in western countries.

    Directory of Open Access Journals (Sweden)

    Mark Levels

    Full Text Available Using new direct measures of numeracy and literacy skills among 85,875 adults in 17 Western countries, we find that foreign-born adults have lower mean skills than native-born adults of the same age (16 to 64 in all of the examined countries. The gaps are small, and vary substantially between countries. Multilevel models reveal that immigrant populations' demographic and socioeconomic characteristics, employment, and language proficiency explain about half of the cross-national variance of numeracy and literacy skills gaps. Differences in origin countries' average education level also account for variation in the size of the immigrant-native skills gap. The more protective labor markets in immigrant-receiving countries are, the less well immigrants are skilled in numeracy and literacy compared to natives. For those who migrate before their teens (the 1.5 generation, access to an education system that accommodates migrants' special needs is crucial. The 1 and 1.5 generation have smaller numeracy and literacy skills gaps in more ethnically diverse societies.

  8. Elaborating the History of Our Cementing Societies

    DEFF Research Database (Denmark)

    Cao, Zhi; Shen, Lei; Løvik, Amund N.

    2017-01-01

    development of cement in-use stocks in residential, nonresidential, and civil engineering sectors of all world countries. We found that global cement production spreads unevenly among 184 countries, with China dominating the global production and consumption after the 1990s. Nearly all countries have shown...

  9. Western-style fast food intake and cardiometabolic risk in an Eastern country.

    Science.gov (United States)

    Odegaard, Andrew O; Koh, Woon Puay; Yuan, Jian-Min; Gross, Myron D; Pereira, Mark A

    2012-07-10

    Western-style fast food contributes to a dietary pattern portending poor cardiometabolic health in the United States. With globalization, this way of eating is becoming more common in developing and recently developed populations. We examined the association of Western-style fast food intake with risk of incident type 2 diabetes mellitus and coronary heart disease mortality in Chinese Singaporeans. This analysis included men and women 45 to 74 years of age who enrolled in the Singapore Chinese Health Study from 1993 to 1998. For CHD mortality, 52 584 participants were included and 1397 deaths were identified through December 31, 2009, via registry linkage. For type 2 diabetes mellitus, 43 176 participants were included and 2252 cases were identified during the follow-up interview (1999-2004) and validated. Hazard ratios for incident type 2 diabetes mellitus and coronary heart disease mortality were estimated with thorough adjustment for demographic, lifestyle, and dietary factors. Chinese Singaporeans with relatively frequent intake of Western-style fast food items (≥2 times per week) had an increased risk of developing type 2 diabetes mellitus (hazard ratio, 1.27; 95% confidence interval, 1.03-1.54) and dying of coronary heart disease (hazard ratio, 1.56; 95% confidence interval, 1.18-2.06) relative to their peers with little or no reported intake. These associations were not materially altered by adjustments for overall dietary pattern, energy intake, and body mass index. Western-style fast food intake is associated with increased risk of developing type 2 diabetes mellitus and of coronary heart disease mortality in an Eastern population. These findings suggest the need for further attention to global dietary acculturation in the context of ongoing epidemiological and nutrition transitions.

  10. Access to information on nuclear safety in some Western countries. Additional expertise commissioned by the Public Debate National Commission

    International Nuclear Information System (INIS)

    Marignac, Y.; Schneider, Th.; Drouet, F.

    2006-01-01

    The authors report the analysis of procedures implemented in different western countries (Switzerland, Finland, United Kingdom, Germany, Sweden and United States) about the access to information on nuclear safety in the broad sense, i.e. as far as population protection against accidental or malevolent situations is concerned. They aimed at analysing how these procedures conciliate pluralism and comprehensive debate while preserving national and industrial interests as well as population's confidence. For each country, they present the different pubic bodies or agencies in charge of nuclear installations and nuclear safety, the existing legal framework related to information on government and nuclear activities, and give examples of information related to nuclear safety (incident or accident concerning nuclear power station or radioactive wastes). The comparative analysis considers different issues: access to information, and pluralist expertise

  11. Peer victimization and subjective health among students reporting disability or chronic illness in 11 Western countries

    DEFF Research Database (Denmark)

    Sentenac, Mariane; Gavin, Aoife; Nic Gabhainn, Saoirse

    2013-01-01

    victimization and poor subjective health according to the D/CI status. RESULTS: Overall, 13.5% of the students reported having been bullied at least two or three times a month. The percentage of victims was significantly higher among those reporting D/CI than among others in all countries studied. Victims...... of bullying were more likely to report poor self-rated health, low life satisfaction and multiple health complaints. However, there were no differences in the associations between peer victimization and subjective health indicators according to the D/CI status. CONCLUSIONS: In all countries studied, students...... reporting D/CI were more likely to report being victims of bullying. Victims of bullying reported more negative subjective health outcomes regardless of their D/CI status. Although inclusive education is currently a major topic of educational policies in most countries, additional efforts should be made...

  12. Who Decides: Me or We? Family Involvement in Medical Decision Making in Eastern and Western Countries.

    Science.gov (United States)

    Alden, Dana L; Friend, John; Lee, Ping Yein; Lee, Yew Kong; Trevena, Lyndal; Ng, Chirk Jenn; Kiatpongsan, Sorapop; Lim Abdullah, Khatijah; Tanaka, Miho; Limpongsanurak, Supanida

    2018-01-01

    Research suggests that desired family involvement (FI) in medical decision making may depend on cultural values. Unfortunately, the field lacks cross-cultural studies that test this assumption. As a result, providers may be guided by incomplete information or cultural biases rather than patient preferences. Researchers developed 6 culturally relevant disease scenarios varying from low to high medical seriousness. Quota samples of approximately 290 middle-aged urban residents in Australia, China, Malaysia, India, South Korea, Thailand, and the USA completed an online survey that examined desired levels of FI and identified individual difference predictors in each country. All reliability coefficients were acceptable. Regression models met standard assumptions. The strongest finding across all 7 countries was that those who desired higher self-involvement (SI) in medical decision making also wanted lower FI. On the other hand, respondents who valued relational-interdependence tended to want their families involved - a key finding in 5 of 7 countries. In addition, in 4 of 7 countries, respondents who valued social hierarchy desired higher FI. Other antecedents were less consistent. These results suggest that it is important for health providers to avoid East-West cultural stereotypes. There are meaningful numbers of patients in all 7 countries who want to be individually involved and those individuals tend to prefer lower FI. On the other hand, more interdependent patients are likely to want families involved in many of the countries studied. Thus, individual differences within culture appear to be important in predicting whether a patient desires FI. For this reason, avoiding culture-based assumptions about desired FI during medical decision making is central to providing more effective patient centered care.

  13. Building Capacity for Structural Reform in Higher Education of Western Balkan Countries

    OpenAIRE

    Barbareev, Kiril

    2011-01-01

    Core Experts’ Group under the scheme of STREW Project The inaugural meeting of the Core Experts’ Group in the Tempus-funded project, ‘Building Capacity for Structural Reform in Higher Education of Western Balkan Countries’ (STREW), was hosted by the HEA on 16 February 2011. The purpose of the meeting was to progress the first of the key activities comprising the first work package of the project, namely to draft a guidelines/questionnaire for self-evaluation reporting by stakeholders in hi...

  14. Labour Market Institutions in the Western Balkan Countries and their Economic Implications: Evidence for Kosova

    OpenAIRE

    MSc. Anera Alishani; BA. Ariana Shabani; Dr.Sc. Muje Gjonbalaj

    2013-01-01

    Flexicurity as one of the most important priorities of employment policies in the EU and its Member States is considered to be also important for the other states of Central and Eastern Europe, including the Western Balkans. According to European Commission (2007, p.7), flexicurity as a combination of flexibility and security in working arrangements can be suggested as an answer to dynamic changes happening in today’s national and international economies; it is an answer to the EU’s dilemma o...

  15. Contextual explanations for numeracy and literacy skill disparities between native and foreign-born adults in western countries

    Science.gov (United States)

    Jencks, Christopher

    2017-01-01

    Using new direct measures of numeracy and literacy skills among 85,875 adults in 17 Western countries, we find that foreign-born adults have lower mean skills than native-born adults of the same age (16 to 64) in all of the examined countries. The gaps are small, and vary substantially between countries. Multilevel models reveal that immigrant populations’ demographic and socioeconomic characteristics, employment, and language proficiency explain about half of the cross-national variance of numeracy and literacy skills gaps. Differences in origin countries’ average education level also account for variation in the size of the immigrant-native skills gap. The more protective labor markets in immigrant-receiving countries are, the less well immigrants are skilled in numeracy and literacy compared to natives. For those who migrate before their teens (the 1.5 generation), access to an education system that accommodates migrants’ special needs is crucial. The 1 and 1.5 generation have smaller numeracy and literacy skills gaps in more ethnically diverse societies. PMID:28301541

  16. Options of biofuel trade from Central and Eastern to Western European countries

    NARCIS (Netherlands)

    van Dam, J.; Faaij, A.P.C.; Lewandowski, I.M.; Van Zeebroeck, B.

    2009-01-01

    Central and Eastern European countries (CEEC) have a substantial biomass production and export potential. The objective of this study is to assess whether the market for biofuels and trade can be profitable enough to realize a supply of biofuels from the CEEC to the European market and to estimate

  17. Trends in higher education : statistical trends in nine Western-European countries, 1990-1999

    NARCIS (Netherlands)

    Kaiser, Frans; Lub, Anneke; Boezerooy, Petra

    2002-01-01

    This presentation is based on the third trendreport in the framework of the CHEPS Higher Education Monitor. In this report the statistical trends over the period 1990-1999 on a number of key indicators from the CHEPS database is presented for the following nine countries: Austria, Denmark, Flanders,

  18. Interethnic contacts : a dynamic analysis of interaction between immigrants and natives in Western countries

    NARCIS (Netherlands)

    Martinovic, B.

    2010-01-01

    This book studies social integration of immigrants (i.e. contacts between immigrants and natives in leisure time) from a dynamic perspective. The central objective is to examine how such interethnic contacts change during the immigrants’ stay in the host country (do they increase, stagnate or

  19. Determinants of Life Satisfaction among Immigrants from Western Countries and from the FSU in Israel

    Science.gov (United States)

    Amit, Karin

    2010-01-01

    This study examines the integration of immigrants via their satisfaction with life in the new country. While most studies on immigrant integration have focused on objective integration parameters such as education, occupation and salary (e.g., Borjas in "Friends or strangers: the impact of immigrants on the US economy." Basic Books, New…

  20. Rectal Tumour Staging with Endorectal Ultrasound: Is There Any Difference between Western and Eastern European Countries?

    Directory of Open Access Journals (Sweden)

    Anna Fábián

    2016-01-01

    Full Text Available Background. Rectal tumour management depends highly on locoregional extension. Rectal endoscopic ultrasound (ERUS is a good alternative to computed tomography and magnetic resonance imaging. However, in Hungary only a small amount of rectal tumours is examined with ERUS. Methods. Our retrospective study (2006–2012 evaluates the diagnostic accuracy of ERUS and compares the results, the first data from Central Europe, with those from Western Europe. The effect of neoadjuvant therapy, rectal probe type, and investigator’s experience were also assessed. Results. 311 of the 647 ERUS assessed locoregional extension. Histological comparison was available in 177 cases: 67 patients underwent surgery alone; 110 received neoadjuvant chemoradiotherapy (CRT; ERUS preceded CRT in 77 and followed it in 33 patients. T-staging was accurate in 72% of primarily operated patients. N-staging was less accurate (62%. CRT impaired staging accuracy (64% and 59% for T- and N-staging. Rigid probes were more accurate (79%. At least 30 examinations are needed to master the technique. Conclusions. The sensitivity of ERUS complies with the literature. ERUS is easy to learn and more accurate in early stages but unnecessary for restaging after CRT. Staging accuracy is similar in Western and Central Europe, although the number of examinations should be increased.

  1. Go East: Differences between Poland and Western European countries in the motivational structures underlying seafood consumption

    DEFF Research Database (Denmark)

    Scholderer, Joachim; Brunsø, Karen; Olsen, Svein Ottar

    Central Europe is an emerging market for seafood products, with rapidly developing opportunities for foreign direct investment and export. Although Poland in particular is widely regarded as a land of opportunity in the seafood business, surprisingly little effort has been made until now to gain...... and compared in terms of the motivational structures underlying seafood consumption. In Poland, intentions to consume seafood in the near future were mainly determined by the perceived difficulty of preparing fish dishes (problems with bone handling and smells) and the degree to which consumers believed...... they had the necessary cooking skills. The preferences of consumers and their household members had a much weaker but still significant impact on intentions. In the comparison samples from Western Europe, motivational structures varied considerably. The highest degree of similarity with Poland was found...

  2. Prevalence of childhood abuse among people who are homeless in Western countries: a systematic review and meta-analysis.

    Science.gov (United States)

    Sundin, Eva C; Baguley, Thom

    2015-02-01

    This article systematically reviews studies of prevalence of childhood experience of physical and sexual abuse in adult people who are homeless in Western countries. Medline, PsychInfo, and the Cochrane Library were searched using the keywords: homeless*, child* abuse, child* trauma, and child* adversity and the bibliographies of identified articles were reviewed. Sources of heterogeneity in the prevalence rates were explored by meta-regression analysis. Twenty-four reports published between January 1990 and August 2013 in three countries provided estimates obtained from up to 9,730 adult individuals who were homeless. Prevalence of reported childhood physical abuse ranged from 6 to 94% with average prevalence of 37%, 95% CI [25, 51]. Reported sexual abuse ranged from 4 to 62%, with average prevalence estimated as 32%, 95% CI [23, 44] for female and 10% for male, 95% CI [6, 17]. Substantial heterogeneity was observed among the studies (I2 ≥ 98%). Including moderators greatly reduced but did not eliminate this heterogeneity. Moderator analyses suggested that reported physical abuse tended to be higher for predominately white samples and tended to be lower for younger samples. Sexual abuse was far more prevalent in predominately female samples and slightly higher in non-US samples and convenience samples. The findings of this study suggest that childhood physical and sexual abuse is more prevalent among the homeless in Western countries than in the global population. Physical abuse appears to be particularly prevalent in younger samples and sexual abuse rates are higher in predominately female samples. Further investigation is needed to advance our understanding of how trauma informed treatment and care for the homeless effectively can take into account the service user's experiences of childhood abuse.

  3. The prevalence of mental disorders among the homeless in western countries: systematic review and meta-regression analysis.

    Directory of Open Access Journals (Sweden)

    Seena Fazel

    2008-12-01

    Full Text Available BACKGROUND: There are well over a million homeless people in Western Europe and North America, but reliable estimates of the prevalence of major mental disorders among this population are lacking. We undertook a systematic review of surveys of such disorders in homeless people. METHODS AND FINDINGS: We searched for surveys of the prevalence of psychotic illness, major depression, alcohol and drug dependence, and personality disorder that were based on interviews of samples of unselected homeless people. We searched bibliographic indexes, scanned reference lists, and corresponded with authors. We explored potential sources of any observed heterogeneity in the estimates by meta-regression analysis, including geographical region, sample size, and diagnostic method. Twenty-nine eligible surveys provided estimates obtained from 5,684 homeless individuals from seven countries. Substantial heterogeneity was observed in prevalence estimates for mental disorders among the studies (all Cochran's chi(2 significant at p 85%. The most common mental disorders were alcohol dependence, which ranged from 8.1% to 58.5%, and drug dependence, which ranged from 4.5% to 54.2%. For psychotic illness, the prevalence ranged from 2.8% to 42.3%, with similar findings for major depression. The prevalence of alcohol dependence was found to have increased over recent decades. CONCLUSIONS: Homeless people in Western countries are substantially more likely to have alcohol and drug dependence than the age-matched general population in those countries, and the prevalences of psychotic illnesses and personality disorders are higher. Models of psychiatric and social care that can best meet these mental health needs requires further investigation.

  4. The Prevalence of Mental Disorders among the Homeless in Western Countries: Systematic Review and Meta-Regression Analysis

    Science.gov (United States)

    Fazel, Seena; Khosla, Vivek; Doll, Helen; Geddes, John

    2008-01-01

    Background There are well over a million homeless people in Western Europe and North America, but reliable estimates of the prevalence of major mental disorders among this population are lacking. We undertook a systematic review of surveys of such disorders in homeless people. Methods and Findings We searched for surveys of the prevalence of psychotic illness, major depression, alcohol and drug dependence, and personality disorder that were based on interviews of samples of unselected homeless people. We searched bibliographic indexes, scanned reference lists, and corresponded with authors. We explored potential sources of any observed heterogeneity in the estimates by meta-regression analysis, including geographical region, sample size, and diagnostic method. Twenty-nine eligible surveys provided estimates obtained from 5,684 homeless individuals from seven countries. Substantial heterogeneity was observed in prevalence estimates for mental disorders among the studies (all Cochran's χ2 significant at p 85%). The most common mental disorders were alcohol dependence, which ranged from 8.1% to 58.5%, and drug dependence, which ranged from 4.5% to 54.2%. For psychotic illness, the prevalence ranged from 2.8% to 42.3%, with similar findings for major depression. The prevalence of alcohol dependence was found to have increased over recent decades. Conclusions Homeless people in Western countries are substantially more likely to have alcohol and drug dependence than the age-matched general population in those countries, and the prevalences of psychotic illnesses and personality disorders are higher. Models of psychiatric and social care that can best meet these mental health needs requires further investigation. PMID:19053169

  5. Questionnaire-based survey on the distribution and incidence of canine babesiosis in countries of Western Europe

    Directory of Open Access Journals (Sweden)

    Halos Lénaïg

    2014-01-01

    Full Text Available The incidence of canine babesiosis may vary considerably from one country to another depending on the distribution of the causative parasite species and their specific vectors. The aim of the present study was to evaluate the clinical occurrence of canine babesiosis diagnosed in European veterinary clinics and propose an updated map of the disease distribution in Western Europe. Questionnaires were sent to companion animal veterinary clinics in Spain, France, Benelux, Germany and Austria. The annual number of babesiosis cases in 2010, the number of practitioners in the clinic and the location of the clinic were recorded. The total numbers of dogs and practitioners in each country were used for definition of the reference populations and the annual incidence of canine babesiosis was calculated by dividing the total number of reported babesiosis cases by the total number of dogs in the veterinary practices involved in the study. Data were georeferenced for distribution map construction. The overall annual incidence of clinical babesiosis amongst the investigated dog population was 0.7%, with significant variations amongst countries and regions. Three epidemiological situations were described: (i Spain, with co-existence of several species of piroplasms and patchy distribution of babesiosis, (ii France, with overall presence of babesiosis due to Babesia canis and local variations and (iii Benelux, Germany and Austria, with overall low prevalence of the disease associated with localised description related either to imported cases or to small autochthonous foci of B. canis infection.

  6. Parenting and globalization in western countries: explaining differences in parent-child interactions.

    Science.gov (United States)

    Prevoo, Mariëlle Jl; Tamis-LeMonda, Catherine S

    2017-06-01

    We review research on intra-cultural differences in parenting, and the sources of those differences. Ethnic-minority parents differ from majority parents in parenting values, childrearing goals and resources-differences that affect parenting practices and children's development. Within-country comparisons indicate less sensitivity, more authoritarian discipline, less child-focused communications, and less engagement in learning activities in ethnic-minority compared to ethnic-majority parents, which help account for disparities in children. Despite group differences in parenting, associations between parenting and child development generalize across cultures, with rare exceptions. However, a focus on intra-cultural differences is based on comparisons of group 'averages', which masks the enormous variation within ethnic-minority samples. Within-group variation can be partly explained by stressors associated with low socioeconomic status (SES), acculturation and discrimination. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. [The current malariological situation in the countries of western Africa. 1. The Republic of Guinea].

    Science.gov (United States)

    Bespiatov, V F; Khromov, A S; Chistiakov, D A; Zhil'tsov, Iu P

    1992-01-01

    Favorable climatic conditions in the Republic of Guinea are conducive to a high prevalence of infectious and parasitic diseases, responsible for 70% of primary consultations of the population, malaria being diagnosed in 40% of cases. Five landscape malariologic zones were singled out in the country, that are characterized by a certain level of malariogenicity. In the lowland/river and mountain/river zones the parasite index of children aged 2 to 9 varied from 16.4 to 45%, and in some foci it reached 63.1%. Foci in the Guinea-Sudan type wet savanna zone are also referred to meso- and hyperendemic ones. The mountain/forest zones are mainly mesoendemic. Malaria foci in the forest/savanna zone in southern Guinea and in the Sierra Leone northern provinces are hyper- and holoendemic, with the parasite index of children aged 2 to 9 being 76.3-92%.

  8. Severe Anemia with Hemoperitoneum as a First Presentation for Multinodular Hepatocellular Carcinoma: A Rare Event in Western Countries

    Directory of Open Access Journals (Sweden)

    Thein Swe

    2016-01-01

    Full Text Available Hemoperitoneum due to spontaneous rupture of hepatocellular carcinoma is a life-threatening and rare condition in western countries with an incidence of less than 3% because of early detection of cirrhosis and neoplasm. Here, we describe a case of a 66-year-old male patient with altered mental status with hemorrhagic shock. Computed tomography scan of abdomen revealed hemoperitoneum and mass in liver. Patient underwent resection of liver tumor and biopsy revealed multinodular hepatocellular carcinoma. A high degree of suspicion is required where severe anemia and hemoperitoneum can be a first presentation for hepatocellular carcinoma especially in patients with chronic hepatitis C infection. Early diagnosis is crucial since mortality rates remain high for untreated cases.

  9. The moral code in Islam and organ donation in Western countries: reinterpreting religious scriptures to meet utilitarian medical objectives.

    Science.gov (United States)

    Rady, Mohamed Y; Verheijde, Joseph L

    2014-06-02

    End-of-life organ donation is controversial in Islam. The controversy stems from: (1) scientifically flawed medical criteria of death determination; (2) invasive perimortem procedures for preserving transplantable organs; and (3) incomplete disclosure of information to consenting donors and families. Data from a survey of Muslims residing in Western countries have shown that the interpretation of religious scriptures and advice of faith leaders were major barriers to willingness for organ donation. Transplant advocates have proposed corrective interventions: (1) reinterpreting religious scriptures, (2) reeducating faith leaders, and (3) utilizing media campaigns to overcome religious barriers in Muslim communities. This proposal disregards the intensifying scientific, legal, and ethical controversies in Western societies about the medical criteria of death determination in donors. It would also violate the dignity and inviolability of human life which are pertinent values incorporated in the Islamic moral code. Reinterpreting religious scriptures to serve the utilitarian objectives of a controversial end-of-life practice, perceived to be socially desirable, transgresses the Islamic moral code. It may also have deleterious practical consequences, as donors can suffer harm before death. The negative normative consequences of utilitarian secular moral reasoning reset the Islamic moral code upholding the sanctity and dignity of human life.

  10. The moral code in Islam and organ donation in Western countries: reinterpreting religious scriptures to meet utilitarian medical objectives

    Science.gov (United States)

    2014-01-01

    End-of-life organ donation is controversial in Islam. The controversy stems from: (1) scientifically flawed medical criteria of death determination; (2) invasive perimortem procedures for preserving transplantable organs; and (3) incomplete disclosure of information to consenting donors and families. Data from a survey of Muslims residing in Western countries have shown that the interpretation of religious scriptures and advice of faith leaders were major barriers to willingness for organ donation. Transplant advocates have proposed corrective interventions: (1) reinterpreting religious scriptures, (2) reeducating faith leaders, and (3) utilizing media campaigns to overcome religious barriers in Muslim communities. This proposal disregards the intensifying scientific, legal, and ethical controversies in Western societies about the medical criteria of death determination in donors. It would also violate the dignity and inviolability of human life which are pertinent values incorporated in the Islamic moral code. Reinterpreting religious scriptures to serve the utilitarian objectives of a controversial end-of-life practice, perceived to be socially desirable, transgresses the Islamic moral code. It may also have deleterious practical consequences, as donors can suffer harm before death. The negative normative consequences of utilitarian secular moral reasoning reset the Islamic moral code upholding the sanctity and dignity of human life. PMID:24888748

  11. Body image perceptions in Western and post-communist countries: a cross-cultural pilot study of children and parents.

    Science.gov (United States)

    Humenikova, Lenka; Gates, Gail E

    2008-07-01

    The development of an unrealistic ideal body image and body size dissatisfaction among children is common in Western countries, including the USA and many European nations. However, little is known about children's body image perceptions in post-communist countries. This pilot study evaluated body image perceptions in a sample of Czech school-aged children and their parents and compared them with the perceptions of American children and parents. Ninety-seven Czech and 45 American 4th-6th graders and their parents from eight urban schools participated in this study. A previously developed silhouette body image instrument was utilized in a parent questionnaire and during child interviews to measure perceived and ideal body image perceptions of children and parents. Descriptive statistics, independent t-tests and paired t-tests were used to compare differences between children's and parents' perceived and ideal body image perceptions. Associations between body image perceptions and other variables were explored using bivariate correlations. American children had a thinner ideal body image compared with Czech children (P image for their children did not differ by nationality (P = 0.858). While the pressure on children to look thinner was apparent among both American and Czech children, Czech children considered a larger body size as more ideal. A future study should evaluate body image perceptions and factors influencing these perceptions in a representative sample of Czech children and parents.

  12. A review of abortion laws in Western-European countries. A cross-national comparison of legal developments between 1960 and 2010.

    Science.gov (United States)

    Levels, Mark; Sluiter, Roderick; Need, Ariana

    2014-10-01

    The extent to which women have had access to legal abortions has changed dramatically in Western-Europe between 1960 and 2010. In most countries, abortion laws developed from completely banning abortion to allowing its availability on request. Both the timing and the substance of the various legal developments differed dramatically between countries. Existing comparative studies on abortion laws in Western-European countries lack detail, usually focus either on first-trimester abortions or second trimester abortions, cover a limited time-span and are sometimes inconsistent with one another. Combining information from various primary and secondary sources, we show how and when the conditions for legally obtaining abortion during the entire gestation period in 20 major Western-European countries have changed between 1960 and 2010. We also construct a cross-nationally comparable classification of procedural barriers that limit abortion access. Our cross-national comparison shows that Western-Europe witnessed a general trend towards decreased restrictiveness of abortion laws. However, legal approaches to regulating abortion are highly different in detail. Abortion access remains limited, sometimes even in countries where abortion is legally available without restrictions relating to reasons. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  13. Contentious Institutions: An Augmented Rational-Actor Analysis of the Origins and Path Dependency of Welfare State Institutions in the Western Countries

    OpenAIRE

    Korpi, Walter

    2000-01-01

    Welfare states in the Western countries have had very similar goals, yet the choice of institutions to approach these shared goals has generated protracted power struggles among major interest groups and great cross-country variation in institutional structures. Relating recent debates on new institutionalism to earlier debates on power, this paper outlines an augmented rational-actor approach to the explanation of the origins of welfare state institutions and of variations in their degree of...

  14. Pacific Rim: A Simulation of a Race through the Western Pacific Rim Countries, Developing Awareness of Their Lands, Peoples, and Customs.

    Science.gov (United States)

    Plantz, Connie; Callis, Janette M.

    This simulation allows students to learn about the lands and customs of the people living in the countries found along the western rim of the Pacific Ocean. The class is divided into eight teams. The phases of the unit include: (1) research; (2) activities; (3) race; and (4) summing up and festival. Each stage of play involves completion of tasks…

  15. A review of abortion laws in Western-European countries. A cross-national comparison of legal developments between 1960 and 2010

    NARCIS (Netherlands)

    Levels, Mark; Sluiter, Roderick; Need, Ariana

    2014-01-01

    The extent to which women have had access to legal abortions has changed dramatically in Western-Europe between 1960 and 2010. In most countries, abortion laws developed from completely banning abortion to allowing its availability on request. Both the timing and the substance of the various legal

  16. Prevalence and clinical implications of epstein-barr virus infection in de novo diffuse large B-cell lymphoma in Western countries

    DEFF Research Database (Denmark)

    Ok, Chi Young; Li, Ling; Xu-Monette, Zijun Y

    2014-01-01

    PURPOSE: Epstein-Barr virus-positive (EBV(+)) diffuse large B-cell lymphoma (DLBCL) of the elderly is a variant of DLBCL with worse outcome that occurs most often in East-Asian countries and is uncommon in the Western hemisphere. We studied the largest cohort of EBV(+) DLBCL, independent of age...

  17. A review of abortion laws in Western-European countries: A cross-national comparison of legal developments between 1960 and 2010

    NARCIS (Netherlands)

    Levels, M.; Sluiter, R.; Need, A.

    2014-01-01

    The extent to which women have had access to legal abortions has changed dramatically in Western-Europe between 1960 and 2010. In most countries, abortion laws developed from completely banning abortion to allowing its availability on request. Both the timing and the substance of the various legal

  18. A Comparison of Food Supply from 1984 to 2009 and Degree of Dietary Westernization in Taiwan with Asian Countries and World Continents

    Directory of Open Access Journals (Sweden)

    Cheau-Jane Peng

    2015-01-01

    Full Text Available Objective. To compare quality, quantity, and trends of food supply from 1984 to 2009 and degree of food westernization in Taiwan with Asian countries and world continents by using food balance data. Methods. We compiled data from food balance sheets of Taiwan and Food and Agriculture Organization, including five continents and three most populated countries each in Eastern, Southern, and Southeastern Asia over the period 1984–2009. Quantity of food supply per capita was referenced to Taiwan food guides. The population-weighted means of food supply from Europe, North America, South America, and Australia and New Zealand continents in terms of energy and nutrient distributions, animal/plant sources, and sugar/alcohol contribution were used as indicators of westernization. Trends of food supply per capita of six food groups were plotted, and linear regression was applied to evaluate food changes. Findings. Taiwan’s food supply provided sufficient quantity in food energy, with the lowest cereals/roots supply and rice to wheat ratio, but the highest meat and oil supplies per capita among the 10 studied Asian countries. Taiwan food supply showed the most westernization among these countries. Conclusion. Food supply of Taiwan, although currently sufficient, indicated some security problems and high tendency of diet westernization.

  19. A review of abortion laws in Western-European countries. A cross-national comparison of legal developments between 1960 and 2010.

    NARCIS (Netherlands)

    Levels, M.; Sluiter, R.; Need, A.

    2014-01-01

    The extent to which women have had access to legal abortions has changed dramatically in Western-Europe between 1960 and 2010. In most countries, abortion laws developed from completely banning abortion to allowing its availability on request. Both the timing and the substance of the various legal

  20. The Media as a Dual Mediator of the Political Agenda–Setting Effect of Protest : A Longitudinal Study in Six Western European Countries

    NARCIS (Netherlands)

    Vliegenthart, R.; Walgrave, S.; Wouters, R.; Hutter, S.; Jennings, W.; Gava, R.; Tresh, A.; Varone, F.; Grossman, E.; Breunig, C.; Brouard, S.; Chaques-Bonafont, L.

    2016-01-01

    The study investigates the impact of media coverage of protest on issue attention in parliament (questions) in six Western European countries. Integrating several data sets on protest, media, and political agendas, we demonstrate that media coverage of protest affects parliamentary agendas: the more

  1. Trends in Daily and Extreme Temperature and Precipitation Indices for the Countries of the Western Indian Ocean, 1975-2008

    Science.gov (United States)

    Aguilar, Enric; Vincent, Lucie A.

    2010-05-01

    In the framework of the project "Renforcement des Capacités des Pays de la COI dans le Domaine de l'Adaptation au Changement Climatique (ACCLIMATE)" (Comission de l'Ocean Indien, COI), a workshop on homogenization of climate data and climate change indices analysis was held in Mauritius in October 2009, using the successful format prepared by the CCl/CLIVAR/JCOMM Expert Team on Climate Change Detection and Indices. Scientists from the five countries in Western Indian Ocean brought daily climatological data from their region for a meticulous assessment of the data quality and homogeneity, and for the preparation of climate change indices which can be used for analyses of changes in climate extremes. Although the period of analysis is very short, it represents a seminal step for the compilation of longer data set and allows us to examine the evolution of climate extremes in the area during the time period identified as the decades where anthropogenic warming es larger than natural forcings. This study first presents some results of the homogeneity assessment using the software package RHtestV3 (Wang and Feng 2009) which has been developed for the detection of changepoints in climatological datasets. Indices based on homogenized daily temperatures and precipitations were also prepared for the analysis of trends at more than 50 stations across the region. The results show an increase in the percentage of warm days and warm nights over 1975-2008 while changes in extreme precipitations are not as consistent.

  2. Violent video game effects on aggression, empathy, and prosocial behavior in eastern and western countries: a meta-analytic review.

    Science.gov (United States)

    Anderson, Craig A; Shibuya, Akiko; Ihori, Nobuko; Swing, Edward L; Bushman, Brad J; Sakamoto, Akira; Rothstein, Hannah R; Saleem, Muniba

    2010-03-01

    Meta-analytic procedures were used to test the effects of violent video games on aggressive behavior, aggressive cognition, aggressive affect, physiological arousal, empathy/desensitization, and prosocial behavior. Unique features of this meta-analytic review include (a) more restrictive methodological quality inclusion criteria than in past meta-analyses; (b) cross-cultural comparisons; (c) longitudinal studies for all outcomes except physiological arousal; (d) conservative statistical controls; (e) multiple moderator analyses; and (f) sensitivity analyses. Social-cognitive models and cultural differences between Japan and Western countries were used to generate theory-based predictions. Meta-analyses yielded significant effects for all 6 outcome variables. The pattern of results for different outcomes and research designs (experimental, cross-sectional, longitudinal) fit theoretical predictions well. The evidence strongly suggests that exposure to violent video games is a causal risk factor for increased aggressive behavior, aggressive cognition, and aggressive affect and for decreased empathy and prosocial behavior. Moderator analyses revealed significant research design effects, weak evidence of cultural differences in susceptibility and type of measurement effects, and no evidence of sex differences in susceptibility. Results of various sensitivity analyses revealed these effects to be robust, with little evidence of selection (publication) bias.

  3. [Assurance and assessment of education quality in occupational medicine of selected countries of Western Europe and the United States. II. USA].

    Science.gov (United States)

    Boczkowski, A

    2000-01-01

    The author discusses the studies undertaken with the general aim to provide education in occupational medicine and assure its quality assessment in some countries of Western Europe advanced more than Poland in this area. It becomes quite evident that despite a widespread interest in quality of education, there is a lack of basic systemic solutions, and a gap between basic theoretical and methodological guidelines and a large number of dispersed reports on concrete analytical and evaluation studies can be still observed. In addition to the presentation of an inside view of research activities carried out in some countries of Western Europe and the United States, based on selected professional publications, the author formulates general conclusions on how the assurance and quality assessment of education in occupational medicine function in those countries.

  4. Intra-organizational dynamics as drivers of entrepreneurship among physicians and managers in hospitals of western countries.

    Science.gov (United States)

    Koelewijn, Wout T; Ehrenhard, Michel L; Groen, Aard J; van Harten, Wim H

    2012-09-01

    During the past decade, entrepreneurship in the healthcare sector has become increasingly important. The aging society, the continuous stream of innovative technologies and the growth of chronic illnesses are jeopardizing the sustainability of healthcare systems. In response, many European governments started to reform healthcare during the 1990s, replacing the traditional logic of medical professionalism with business-like logics. This trend is expected to continue as many governments will have to reduce their healthcare spending in response to the current growing budget deficits. In the process, entrepreneurship is being stimulated, yet little is known about intra-hospital dynamics leading to entrepreneurial behavior. The purpose of this article is to review existing literature concerning the influence of intra-organizational dynamics on entrepreneurship among physicians and managers in hospitals of Western countries. Therefore, we conducted a theory-led, systematic review of how intra-organizational dynamics among hospital managers and physicians can influence entrepreneurship. We designed our review using the neo-institutional framework of Greenwood and Hinings (1996). We analyze these dynamics in terms of power dependencies, interest dissatisfaction and value commitments. Our search revealed that physicians' dependence on hospital management has increased along with healthcare reforms and the resulting emphasis on business logics. This has induced various types of responses by physicians. Physicians can be pushed to adopt an entrepreneurial attitude as part of a defensive value commitment toward the business-like healthcare logic, to defend their traditionally dominant position and professional autonomy. In contrast, physicians holding a transformative attitude toward traditional medical professionalism seem more prone to adopt the entrepreneurial elements of business-like healthcare, encouraged by the prospect of increased autonomy and income. Interest

  5. CEMENT SLURRIES FOR GEOTHERMAL WELLS CEMENTING

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    1994-12-01

    Full Text Available During a well cementing special place belongs to the cement slurry design. To ensure the best quality of cementing, a thorough understanding of well parameters is essential, as well as behaviour of cement slurry (especially at high temperatures and application of proven cementing techniques. Many cement jobs fail because of bad job planning. Well cementing without regarding what should be accomplished, can lead to well problems (channels in the cement, unwanted water, gas or fluid production, pipe corrosion and expensive well repairs. Cementing temperature conditions are important because bot-tomhole circulating temperatures affect slurry thickening time, arheology, set time and compressive strength development. Knowing the actual temperature which cement encounters during placement allows the selection of proper cementing materials for a specific application. Slurry design is affected by well depth, bottom hole circulating temperature and static temperature, type or drilling fluid, slurry density, pumping time, quality of mix water, fluid loss control, flow regime, settling and free water, quality of cement, dry or liquid additives, strength development, and quality of the lab cement testing and equipment. Most Portland cements and Class J cement have shown suitable performances in geot-hermal wells. Cement system designs for geothermal wells differ from those for conventional high temperature oil and gas wells in the exclusive use of silica flour instead of silica sand, and the avoidance of fly ash as an extender. In this paper, Portland cement behaviour at high temperatures is described. Cement slurry and set cement properties are also described. Published in literature, the composition of cement slurries which were tested in geothermal conditions and which obtained required compressive strength and water permeability are listed. As a case of our practice geothermal wells Velika Ciglena-1 and Velika Ciglena-la are described.

  6. Cement replacement materials. Properties, durability, sustainability

    International Nuclear Information System (INIS)

    Ramezanianpour, Ali Akbar

    2014-01-01

    The aim of this book is to present the latest findings in the properties and application of Supplementary Cementing Materials and blended cements currently used in the world in concrete. Sustainability is an important issue all over the world. Carbon dioxide emission has been a serious problem in the world due to the greenhouse effect. Today many countries agreed to reduce the emission of CO2. Many phases of cement and concrete technology can affect sustainability. Cement and concrete industry is responsible for the production of 7% carbon dioxide of the total world CO2 emission. The use of supplementary cementing materials (SCM), design of concrete mixtures with optimum content of cement and enhancement of concrete durability are the main issues towards sustainability in concrete industry.

  7. Socioeconomic development as a determinant of the levels of organochlorine pesticides and PCBs in the inhabitants of Western and Central African countries

    Energy Technology Data Exchange (ETDEWEB)

    Luzardo, Octavio P., E-mail: operez@dcc.ulpgc.es [Toxicology Unit, Department of Clinical Sciences, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria (Spain); Boada, Luis D. [Toxicology Unit, Department of Clinical Sciences, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria (Spain); Carranza, Cristina [Infectious Diseases and Tropical Medicine Unit, Hospital Universitario Insular de Gran Canaria, Las Palmas de Gran Canaria (Spain); Medical Sciences and Surgery Department, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria (Spain); Ruiz-Suárez, Norberto; Henríquez-Hernández, Luis Alberto; Valerón, Pilar F.; Zumbado, Manuel; Camacho, María [Toxicology Unit, Department of Clinical Sciences, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria (Spain); Arellano, José Luis Pérez [Infectious Diseases and Tropical Medicine Unit, Hospital Universitario Insular de Gran Canaria, Las Palmas de Gran Canaria (Spain); Medical Sciences and Surgery Department, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria (Spain)

    2014-11-01

    Several studies of environmental samples indicate that the levels of many persistent organic pollutants (POPs) are increasing in Africa, but few studies have been conducted in humans. Simultaneously, many African countries are experiencing a rapid economic growth and implementing information and communication technologies (ICT). These changes have generated high amounts of electronic waste (e-waste) that have not been adequately managed. We tested the hypothesis that the current levels of two main classes of POPs in Western and Central African countries are affected by the degree of socioeconomic development. We measured the levels of 36 POPs in the serum of recent immigrants (N = 575) who came from 19 Sub-Saharan countries to the Canary Islands (Spain). We performed statistical analyses on their anthropometric and socioeconomic data. High median levels of POPs were found in the overall sample, with differences among the countries. Organochlorine pesticide (OCP) and polychlorinated biphenyl (PCB) levels increased with age. People from low-income countries had significantly higher OCP levels and much lower PCB levels than those from high-income countries. We found a significant association between the implementation of ICT and PCB contamination. Immigrants from the countries with a high volume of imports of second-hand electronic equipment had higher PCB levels. The economic development of Africa and the e-waste generation have directly affected the levels of POPs. The POP legacies of these African populations most likely are due to the inappropriate management of the POPs' residues. - Highlights: • Higher levels of organochlorine pesticides in Africans from low-income countries • Higher levels of PCBs in Africans from high-income countries • Levels of PCBs are significantly higher in people from West Africa. • Significant association between implementation of ICT and PCB contamination • High volume of second-hand electronic equipment is associated

  8. Socioeconomic development as a determinant of the levels of organochlorine pesticides and PCBs in the inhabitants of Western and Central African countries

    International Nuclear Information System (INIS)

    Luzardo, Octavio P.; Boada, Luis D.; Carranza, Cristina; Ruiz-Suárez, Norberto; Henríquez-Hernández, Luis Alberto; Valerón, Pilar F.; Zumbado, Manuel; Camacho, María; Arellano, José Luis Pérez

    2014-01-01

    Several studies of environmental samples indicate that the levels of many persistent organic pollutants (POPs) are increasing in Africa, but few studies have been conducted in humans. Simultaneously, many African countries are experiencing a rapid economic growth and implementing information and communication technologies (ICT). These changes have generated high amounts of electronic waste (e-waste) that have not been adequately managed. We tested the hypothesis that the current levels of two main classes of POPs in Western and Central African countries are affected by the degree of socioeconomic development. We measured the levels of 36 POPs in the serum of recent immigrants (N = 575) who came from 19 Sub-Saharan countries to the Canary Islands (Spain). We performed statistical analyses on their anthropometric and socioeconomic data. High median levels of POPs were found in the overall sample, with differences among the countries. Organochlorine pesticide (OCP) and polychlorinated biphenyl (PCB) levels increased with age. People from low-income countries had significantly higher OCP levels and much lower PCB levels than those from high-income countries. We found a significant association between the implementation of ICT and PCB contamination. Immigrants from the countries with a high volume of imports of second-hand electronic equipment had higher PCB levels. The economic development of Africa and the e-waste generation have directly affected the levels of POPs. The POP legacies of these African populations most likely are due to the inappropriate management of the POPs' residues. - Highlights: • Higher levels of organochlorine pesticides in Africans from low-income countries • Higher levels of PCBs in Africans from high-income countries • Levels of PCBs are significantly higher in people from West Africa. • Significant association between implementation of ICT and PCB contamination • High volume of second-hand electronic equipment is associated

  9. How are countries in the Western Pacific Region tracking the HIV epidemic? Results from a 2011 survey of ministries of health.

    Science.gov (United States)

    Yu, Dongbao; Wi, Teodora; Calleja, Jesus Garcia

    2013-01-01

    In 2011, as part of the World Health Organization global reporting tool to collect data on the progress of improving the health sector response to HIV/AIDS towards universal access, a questionnaire was sent to ministries of health of Western Pacific Region Member States on the scope and functioning of their HIV surveillance systems. Of the 17 countries that responded, 13 were low- to middle-income countries and four were high-income countries. Regular serosurveillance surveys are conducted with female sex workers in all lower- and middle-income countries that responded to the survey but less so with people who inject drugs and men who have sex with men. Furthermore, there are no surveillance activities of the key populations in most of the Pacific island countries. It is recommended that estimations of high-risk populations be conducted in priority Pacific island countries and tailored surveillance systems be designed. Efforts should also be made to gather and accumulate data from sufficient geographic coverage to allow the HIV epidemic to continue to be monitored.

  10. Institutional shifts in inter-municipal service delivery: an analysis of developments in eight Western European countries

    NARCIS (Netherlands)

    Hulst, J.R.; van Montfort, A.J.G.M.; Haveri, A.; Airaksinen, J.; Kelly, J.

    2009-01-01

    Comparative research on inter-municipal cooperation in eight European countries shows that there is a great variety of institutional arrangements for cooperation across the different countries. Also, these arrangements tend to change over time in terms of the scope of cooperation among partners,

  11. Is the Mediterranean diet a feasible approach to preserving cognitive function and reducing risk of dementia for older adults in Western countries? New insights and future directions.

    Science.gov (United States)

    Knight, Alissa; Bryan, Janet; Murphy, Karen

    2016-01-01

    The rise in the ageing population has resulted in increased incident rates of cognitive impairment and dementia. The subsequent financial and societal burden placed on an already strained public health care system is of increasing concern. Evidence from recent studies has revealed modification of lifestyle and dietary behaviours is, at present, the best means of prevention. Some of the most important findings, in relation to the Mediterranean diet (MedDiet) and the contemporary Western diet, and potential molecular mechanisms underlying the effects of these two diets on age-related cognitive function, are discussed in this review. A major aim of this review was to discuss whether or not a MedDiet intervention would be a feasible preventative approach against cognitive decline for older adults living in Western countries. Critical appraisal of the literature does somewhat support this idea. Demonstrated evidence highlights the MedDiet as a potential strategy to reduce cognitive decline in older age, and suggests the Western diet may play a role in the aetiology of cognitive decline. However, strong intrinsic Western socio-cultural values, traditions and norms may impede on the feasibility of this notion. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. North Korea's Trade Expansion with Western Countries in the Early 1970's and Its Implications on North Korea's Current Attempts at Economic Rehabilitation

    Directory of Open Access Journals (Sweden)

    Jong-Woon Lee

    2002-12-01

    Full Text Available The purpose of this study is to provide the analytical background of North Korea's trade expansion with Western countries in the early 1970's and examine in depth the resulting impacts on the North Korean economy. Indeed, this study explores the implications of the mechanism and consequences of North Korea's increased trade with Western countries in the 1970's for the current situation of the country's trade expansion based on the rapid increase in imports and large trade deficit. As a result of researching North Korea's economic trajectory during the 1970's within this focus, this study asserts that, despite some positive aspects, North Korea's rapid increase of foreign trade in recent years possesses the immanent possibility of generating serious obstacles to the process of economic recovery. In this vein, this paper intends to explore some policy options North Korea should choose in order to create conditions conducive to economic rehabilitation and prevent the recurrence of similar situation as experienced in the 1970's.

  13. Socioeconomic development as a determinant of the levels of organochlorine pesticides and PCBs in the inhabitants of Western and Central African countries.

    Science.gov (United States)

    Luzardo, Octavio P; Boada, Luis D; Carranza, Cristina; Ruiz-Suárez, Norberto; Henríquez-Hernández, Luis Alberto; Valerón, Pilar F; Zumbado, Manuel; Camacho, María; Arellano, José Luis Pérez

    2014-11-01

    Several studies of environmental samples indicate that the levels of many persistent organic pollutants (POPs) are increasing in Africa, but few studies have been conducted in humans. Simultaneously, many African countries are experiencing a rapid economic growth and implementing information and communication technologies (ICT). These changes have generated high amounts of electronic waste (e-waste) that have not been adequately managed. We tested the hypothesis that the current levels of two main classes of POPs in Western and Central African countries are affected by the degree of socioeconomic development. We measured the levels of 36 POPs in the serum of recent immigrants (N=575) who came from 19 Sub-Saharan countries to the Canary Islands (Spain). We performed statistical analyses on their anthropometric and socioeconomic data. High median levels of POPs were found in the overall sample, with differences among the countries. Organochlorine pesticide (OCP) and polychlorinated biphenyl (PCB) levels increased with age. People from low-income countries had significantly higher OCP levels and much lower PCB levels than those from high-income countries. We found a significant association between the implementation of ICT and PCB contamination. Immigrants from the countries with a high volume of imports of second-hand electronic equipment had higher PCB levels. The economic development of Africa and the e-waste generation have directly affected the levels of POPs. The POP legacies of these African populations most likely are due to the inappropriate management of the POPs' residues. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Are All Socialists Anti-religious? Anti-religiosity and the Socialist Left in 21 Western European Countries (1990-2008

    Directory of Open Access Journals (Sweden)

    Эгберт Рибберинк

    2016-12-01

    Full Text Available The political situation in the Soviet Union during the twentieth century has led some to suggest that socialism is some kind of secular religion as opposed to ‘normal’ religion. In modern Europe, however, there have been vibrant Christian socialist movements. This article looks into the different attitudes of socialists towards religion and answers the question whether it is pressure of religious activity or pressure of religious identity that makes socialists resist religion. The results from a multilevel analysis of three waves of the European Values Study (1990-2008 in 21 Western European countries specifically point to an increase in anti-religiosity by socialists in countries marked by Catholic and Orthodox religious identities.

  15. Blood donation barriers and facilitators of Sub-Saharan African migrants and minorities in Western high-income countries: a systematic review of the literature.

    Science.gov (United States)

    Klinkenberg, E F; Huis In 't Veld, E M J; de Wit, P D; van Dongen, A; Daams, J G; de Kort, W L A M; Fransen, M P

    2018-03-01

    The present study aimed to gain more insight into, and summarise, blood donation determinants among migrants or minorities of Sub-Saharan heritage by systematically reviewing the current literature. Sub-Saharan Africans are under-represented in the blood donor population in Western high-income countries. This causes a lack of specific blood types for transfusions and prevention of alloimmunisation among Sub-Saharan African patients. Medline, EMBASE, PsycINFO and BIOSIS were searched for relevant empirical studies that focused on barriers and facilitators of blood donation among Sub-Saharan Africans in Western countries until 22 June 2017. Of the 679 articles screened by title and abstract, 152 were subsequently screened by full text. Paired reviewers independently assessed the studies based on predefined eligibility and quality criteria. Of the 31 included studies, 24 used quantitative and 7 used qualitative research methods. Target cohorts varied from Black African Americans and refugees from Sub-Sahara Africa to specific Sub-Saharan migrant groups such as Comorians or Ethiopians. Main recurring barriers for Sub-Saharan Africans were haemoglobin deferral, fear of needles and pain, social exclusion, lack of awareness, negative attitudes and accessibility problems. Important recurring facilitators for Sub-Saharan Africans were altruism, free health checks and specific recruitment and awareness-raising campaigns. The findings of this review can be used as a starting point to develop recruitment and retention strategies for Sub-Saharan African persons. Further research is needed to gain more insight in the role of these determinants in specific contexts as socioeconomic features, personal histories and host country regulations may differ per country. © 2018 The Authors. Transfusion Medicine published by John Wiley & Sons Ltd on behalf of British Blood Transfusion Society.

  16. Nurse prescribing of medicines in Western European and Anglo-Saxon countries: a systematic review of the literature.

    NARCIS (Netherlands)

    Kroezen, M.; Dijk, L. van; Groenewegen, P.P.; Francke, A.L.

    2011-01-01

    Background: A growing number of countries are introducing some form of nurse prescribing. However, international reviews concerning nurse prescribing are scarce and lack a systematic and theoretical approach. The aim of this review was twofold: firstly, to gain insight into the scientific and

  17. Building multi-country collaboration on watershed management: lessons on linking environment and public health from the Western Balkans

    Science.gov (United States)

    Community-based watershed resilience programs that bridge public health and environmental outcomes often require cross-boundary, multi-country collaboration. The CRESSIDA project, led by the Regional Environmental Center for Central and Eastern Europe (REC) and supported by the U...

  18. Nurse prescribing of medicines in Western European and Anglo-Saxon countries: a systematic review of the literature.

    NARCIS (Netherlands)

    Kroezen, M.; Dijk, L. van; Groenewegen, P.P.; Francke, A.L.

    2011-01-01

    BACKGROUND: A growing number of countries are introducing some form of nurse prescribing. However, international reviews concerning nurse prescribing are scarce and lack a systematic and theoretical approach. The aim of this review was twofold: firstly, to gain insight into the scientific and

  19. The prevalence of mental disorders among the homeless in western countries: systematic review and meta-regression analysis.

    OpenAIRE

    Seena Fazel; Vivek Khosla; Helen Doll; John Geddes

    2008-01-01

    Editors' Summary Background. In 2007, it was estimated that there were more than 1 million homeless people worldwide. The true magnitude of the problem is difficult to estimate with no internationally agreed definition for homelessness and with the different approaches taken by countries and organizations in counting homeless people. What we do know is that this is a diverse group of people who have poorer physical and mental health than the general population, leading to premature death. We ...

  20. Using reference nutrient density goals with food balance sheet data to identify likely micronutrient deficits for fortification planning in countries in the Western Pacific region.

    Science.gov (United States)

    Gibson, Rosalind S; Cavalli-Sforza, Tommaso

    2012-09-01

    Collection of nationwide food consumption data at the individual level is the preferred option for planning fortification programs. However, such data are seldom collected in low-income countries. In contrast, Food Balance Sheets (FBS), published annually for approximately 180 countries, may provide a source of national data for program planning. To explore the use of micronutrient densities from FBS data to identify likely deficits for eight micronutrients in national diets. Micronutrient densities in the daily available food supply per capita were calculated from the micronutrient contents of 95 food commodities in 17 Western Pacific Region countries. Densities were compared with reference nutrient density goals developed to ensure that at least 95% of individuals, irrespective of life-stage group, are likely to have adequate intakes. Of the eight micronutrients, Cambodia and Korea D.P.R. had likely deficits for six; China, Fiji, Kiribati, Korea Republic, Lao P.D.R., Philippines, Solomon Islands, Vanuatu, and Viet Nam had likely deficits for five; Brunei Darussalam, Malaysia, Mongolia, New Zealand, and Papua New Guinea had likely deficits for four; and New Caledonia had likely deficits for three. The most frequent deficits were for iron, zinc, and calcium (all countries), followed by vitamin B2 and vitamin A (n = 13), vitamin B1 (n = 2), and vitamin B12 (n = 1). The nutrient density approach could be applied to FBS data for ranking countries according to likely micronutrient deficits, but it provides no information on distribution of nutrient supply for fortification program planning. The approach described here could be applied to data from Household Consumption and Expenditures Surveys (HCES) to characterize households at greatest risk.

  1. Cements research progress. 1988

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    This book reviews a survey of the literature on the science of cements published during 1988. The book focuses on an aspect of cement utilization of increasing importance, the immobilization of nuclear wastes

  2. The European Struggle to Educate and Include Roma People: A Critique of Differences in Policy and Practice in Western and Eastern EU Countries

    Directory of Open Access Journals (Sweden)

    Christine O'Hanlon

    2016-02-01

    Full Text Available Multiculturalism is an established feature of the UK and other European States since the establishment of the Treaty of Rome in 1959. Enlargement has brought EU membership from six (1952 to twenty eight members since its foundation, and allowed free migration across its borders. However, many countries, in spite of agreements to adhere to ‘democratic’ practices, deny minority citizens their full rights, particularly in education contexts. Some recent accession EU States have education systems that are less adaptive to expected policy responsibilities. It is a more unstable aspect of Eastern Europe because of the failure of many of these countries to reduce social and educational inequalities and to establish rights for minority groups, particularly the Roma. An educational focus is used as a platform to highlight issues re the segregation, and discrimination against, Roma children in Europe, typically through the use of special education, which is not suitable for them. Europe generally, both East and West has failed to fully integrate the Roma. Often, institutional blame is placed on Roma communities, rather than situate them socially and economically due to ingrained structural inequalities. Stereotyped categories are often used to ‘label’ them. Countries with high Roma populations, four in Western and five in Eastern Europe are evaluated and compared in relation to the education of Roma children.

  3. Sulfur polymer cement concrete

    International Nuclear Information System (INIS)

    Weber, H.H.; McBee, W.C.

    1990-01-01

    Sulfur-based composite materials formulated using sulfur polymer cement (SPC) and mineral aggregates are described and compared with conventional portland cement based materials. Materials characteristics presented include mechanical strength, chemical resistance, impact resistance, moisture permeation, and linear shrinkage during placement and curing. Examples of preparation and placement of sulfur polymer cement concrete (SC) are described using commercial scale equipment. SC applications presented are focused into hostile chemical environments where severe portland cement concrete (PCC) failure has occurred

  4. Self-management Following a Cardiac Event in People of Chinese Ethnicity Living in Western Countries: A Scoping Review.

    Science.gov (United States)

    Zhang, Ling; Gallagher, Robyn; Ding, Ding; Neubeck, Lis

    2017-04-13

    Health outcomes and impact of cardiovascular disease vary between populations, where ethnic minorities and immigrant groups are more likely to be disadvantaged. Compared with the majority residents, health outcomes, especially short-term mortality from coronary heart disease event are worse in people of Chinese ethnicity, potentially due to poor self-management and experiences with the healthcare system in host countries. A scoping review was conducted. Four overarching themes were found: (1) understanding of heart disease, risk factors and symptom recognition, (2) adherence to medication and lifestyle modification, (3) health service/information choice, and (4) family role in disease self-management and decision making. All themes were greatly influenced by English language proficiency and cultural practices. English language proficiency and cultural practices should be taken into consideration when providing healthcare services for people of Chinese ethnicity, as it plays an important role in self-management and experiences with the healthcare system.

  5. Implementing preventive iron-folic acid supplementation among women of reproductive age in some Western Pacific countries: possibilities and challenges.

    Science.gov (United States)

    Smitasiri, Suttilak; Solon, Florentino S

    2005-12-01

    Lack of effective implementation mechanisms is identified as a major obstacle in the prevention and control of iron-deficiency anemia. This paper discusses experiences gained from implementing iron-folic acid supplementation in the Philippines, Vietnam, and Cambodia. The understanding of contextual elements is proposed as a foundation for planning interventions. Moreover, it is suggested that a social marketing framework should provide a way of thinking about how to influence related behaviors. The application of a social marketing framework applied using a "5 P's" approach: public relations and collaboration, product, price, place, and promotion, is described, as well as enabling factors (possibilities) and inhibiting factors (challenges) of this approach. Although a program to improve iron nutrition among women of reproductive age may not be simple to implement, it is essential to enhancing health, human development, and economic advancement in developing countries.

  6. The relationship between the traditional and contemporary elements in the church architecture of the Western Christian countries in the 20th century

    Directory of Open Access Journals (Sweden)

    Manić Božidar

    2015-01-01

    Full Text Available Church architecture has been developing continually within Western Christianity since the 4th century, It gradually becomes less important from the end of the Middle Ages, especially with the advent of the ideas of Reformation and Enlightment, going almost out of the focus of contemporary architecture with the advent of modernism in the 20th century. The most important factors for the development of this building type in the 20th century, were the emergence of modernism in architecture and strengthening of the movements of liturgical renewal. It was a time in which the diametrically opposed concepts - radically modernizing and conservatively traditional - were expressed to the extreme, with many transitional forms, Striving to active participation of believers can lead to completely different results - strengthening the liturgical assembly, on one hand, and radical desacralisation of worship, on the other. There is a large number of architectural solutions, some of which share common characteristics concerning spatial organization and the distribution of laity and clergy, but with a great diversity of other architectural characteristics and different relations of traditional and contemporary elements. The experiences of Western Christian countries can be of use, to some extent, in the research of contemporary Orthodox church architecture.

  7. CHH Cement Composite

    Science.gov (United States)

    Cwirzen, A.; Habermehl-Cwirzen, K.; Nasibulina, L. I.; Shandakov, S. D.; Nasibulin, A. G.; Kauppinen, E. I.; Mudimela, P. R.; Penttala, V.

    The compressive strength and electrical resistivity for hardened pastes produced from nanomodified Portland SR cement (CHH- Carbon Hedge Hog cement) were studied. The nanomodification included growing of carbon nanotubes (CNTs) and carbon nanofibers (CNFs) on the cement particles. Pastes having water to binder ratio of 0.5 were produced. The obtained hardened material was characterized by increased compressive strength in comparison with the reference specimens made from pristine SR cement, which was attributed to reinforcing action of the CNTs and CNFs. The electrical resistivity of CHH composite was lower by one order of magnitude in comparison with reference Portland cement paste.

  8. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2001-04-15

    The objective of this project is to develop an improved ultra-lightweight cement using ultralight hollow glass spheres (ULHS). Work reported herein addresses Task 1: Assess Ultra-Lightweight Cementing Problems and Task 3: Test Ultra-Lightweight Cements. Results reported this quarter include a review and summary of Halliburton Energy Services (HES) and BJ Services historical performance data for lightweight cement applications. These data are analyzed and compared to ULHS cement and foamed cement performances. Similar data is expected from Schlumberger, and an analysis of this data will be completed in the following phases of the project. Quality control testing of materials used to formulate ULHS cements in the laboratory was completed to establish baseline material performance standards. A testing protocol was developed employing standard procedures as well as procedures tailored to evaluate ULHS and foamed cement. This protocol is presented and discussed. Results of further testing of ULHS cements are presented along with an analysis to establish cement performance design criteria to be used during the remainder of the project. Finally, a list of relevant literature on lightweight cement performance is compiled for review during the next quarter.

  9. Trends and patterns of antidepressant use in children and adolescents from five western countries, 2005-2012

    DEFF Research Database (Denmark)

    Bachmann, Christian J; Aagaard, Lise; Burcu, Mehmet

    2016-01-01

    and stratified by age, sex, and according to subclass and specific drug. Across the years, the prevalence of ATD use increased from 1.3% to 1.6% in the US data (+26.1%); 0.7% to 1.1% in the UK data (+54.4%); 0.6% to 1.0% in Denmark data (+60.5%); 0.5% to 0.6% in the Netherlands data (+17.6%); and 0.3% to 0......Following the FDA black box warning in 2004, substantial reductions in antidepressant (ATD) use were observed within 2 years in children and adolescents in several countries. However, whether these reductions were sustained is not known. The objective of this study was to assess more recent trends...... in ATD use in youth (0-19 years) for the calendar years 2005/6-2012 using data extracted from regional or national databases of Denmark, Germany, the Netherlands, the United Kingdom (UK), and the United States (US). In a repeated cross-sectional design, the annual prevalence of ATD use was calculated...

  10. The use of Limestone Powder as an Alternative Cement Replacement

    African Journals Online (AJOL)

    user

    cement productivity, reduced production cost and environmental protection with a significant reduction of CO2 and ... The use of limestone filler in combination with. Portland cement is a common practice in many countries in .... in plastic bags with a content of 1350 g. Water. Throughout the investigation, tap water supplied.

  11. Prolactinoma and hyperprolactinaemia: a transcultural comparative study between Germany as a western, liberal, industrialised country and Syria as an oriental society with a strong Islamic tradition.

    Science.gov (United States)

    Kann, Peter Herbert; Juratli, Nour; Kabalan, Younes

    2010-10-01

    Prolactinomas and hyperprolactinaemia cause hypogonadism and impairment of sexual and reproductive function. In this transcultural study, clinical characteristics of prolactinoma/hyperprolactinaemia were compared between a liberal, western, industrialised country and a more traditional, Islamic, oriental society. Sixty-two Syrian patients with hyperprolactinaemia were compared to 62 German patients with hyperprolactinaemia. In Syria and Germany, prolactinoma and hyperprolactinaemia were more frequent in females than in males (Syria 87% females; Germany 63% females). Prolactinomas were larger in males, males were older at diagnosis in both countries. Recorded clinical symptoms were comparable, even if culturally determined differences in spontaneous reporting of and asking for symptoms might be considered. The average age of the Syrian patients at diagnosis of hyperprolactinaemia was more than 6 years lower than in the German cohort (33.4 ± 10.4 vs. 39.7 ± 17.6 years). In Germany, a variety of therapeutic regimens were applied. In Syria, bromocriptine was prescribed exclusively. The differences may be attributed to culturally determined differences in sexual and reproductive behaviour, i.e. sexual intercourses of young, unmarried girls and women in association to the use of oral contraceptives regulating the menstrual cycle, maternal age at first delivery and birth frequency. Exclusive prescription of bromocriptine in Syria may be associated to limited resources and the safety of bromocriptine during pregnancy.

  12. Cement for Oil Well Cementing Operations in Ghana

    African Journals Online (AJOL)

    Michael

    performance of three locally manufactured cement samples and imported class G cement sample for oil and gas well ... cement. 2 Materials and Methods. 2.1 Materials. Three brands of cement available on the Ghanaian market and commonly used by Ghanaians for construction ..... Cement Slurry using Factorial Design”,.

  13. Coronary heart disease incidence among non-Western immigrants compared to Danish-born people: effect of country of birth, migrant status, and income.

    Science.gov (United States)

    Bo, Anne; Zinckernagel, Line; Krasnik, Allan; Petersen, Jorgen H; Norredam, Marie

    2015-10-01

    Increasing global migration has made immigrants' health an important topic worldwide. We examined the effect of country of birth, migrant status (refugee/family-reunified) and income on coronary heart disease (CHD) incidence. This was a historical prospective register-based cohort study. The study cohort consisted of immigrants above 18 years from non-Western countries who had obtained a residence permit in Denmark as a refugee (n = 29,045) or as a family-reunified immigrant (n = 28,435) from 1 January 1993-31 December 1999 and a Danish-born reference population (n = 229,918). First-time CHD incidence was identified from 1 January 1993-31 December 2007. Incidence ratios for 11 immigrant groups were estimated using Cox regression analysis. Immigrants from Afghanistan, Iraq, Turkey, Eastern Europe and Central Asia, South Asia, the Former Yugoslavia, and the Middle East and North Africa had significantly higher incidences of CHD (hazard ratio (HR) = 1.36; 95% confidence interval (CI): 1.05-1.75 to HR = 2.86; 95% CI: 2.01-4.08) compared with Danish-born people. Immigrants from Somalia, South and Middle America, Sub-Saharan Africa and women from East Asia and the Pacific did not differ significantly from Danish-born people, whereas immigrant men from East Asia and the Pacific had a significantly lower incidence (HR = 0.32; 95% CI: 0.17-0.62). When also including migrant status, the higher incidences were reduced. Refugee men (HR = 1.35; 95% CI: 1.11-1.65) and women (HR = 1.33; 95% CI: 1.08-1.65) had a significantly higher incidence of CHD than family-reunified immigrants. When migrant status and income were included simultaneously, the incidences decreased to an insignificant level for most immigrant groups. Most non-Western immigrant groups had a higher incidence of CHD than Danish-born people. The study revealed that migrant status and income are important underlying mechanisms of the effect of country of birth on CHD. © The European

  14. Recent and future of cement and concrete industries- a root of our development

    Directory of Open Access Journals (Sweden)

    Ts Erdenebat

    2014-09-01

    Full Text Available This paper considers that cement and concrete industry is contributing to our country development positively, and cement and concrete industry also can be reduced environmental pressure by;- Continuously reducing the CO2 emission from cement production by increased use of biofuels and alternative raw materials as well as introducing modified low energy clinker types and cement with reduced clinker content or geopolymer cement and a new type concrete.- Exploiting the potential of waste bricks, cement and concrete recycling to decrease the emission of CO2.- Exploiting the thermal mass of concrete to create energy optimized solutions for heating and cooling residential and office buildings.

  15. Systemic Measures and Legislative and Organizational Frameworks Aimed at Preventing or Mitigating Drug Shortages in 28 European and Western Asian Countries

    Directory of Open Access Journals (Sweden)

    Tomasz Bochenek

    2018-01-01

    Full Text Available Drug shortages have been identified as a public health problem in an increasing number of countries. This can negatively impact on the quality and efficiency of patient care, as well as contribute to increases in the cost of treatment and the workload of health care providers. Shortages also raise ethical and political issues. The scientific evidence on drug shortages is still scarce, but many lessons can be drawn from cross-country analyses. The objective of this study was to characterize, compare, and evaluate the current systemic measures and legislative and organizational frameworks aimed at preventing or mitigating drug shortages within health care systems across a range of European and Western Asian countries. The study design was retrospective, cross-sectional, descriptive, and observational. Information was gathered through a survey distributed among senior personnel from ministries of health, state medicines agencies, local health authorities, other health or pharmaceutical pricing and reimbursement authorities, health insurance companies and academic institutions, with knowledge of the pharmaceutical markets in the 28 countries studied. Our study found that formal definitions of drug shortages currently exist in only a few countries. The characteristics of drug shortages, including their assortment, duration, frequency, and dynamics, were found to be variable and sometimes difficult to assess. Numerous information hubs were identified. Providing public access to information on drug shortages to the maximum possible extent is a prerequisite for performing more advanced studies on the problem and identifying solutions. Imposing public service obligations, providing the formal possibility to prescribe unlicensed medicines, and temporary bans on parallel exports are widespread measures. A positive finding of our study was the identification of numerous bottom-up initiatives and organizational frameworks aimed at preventing or mitigating

  16. Systemic Measures and Legislative and Organizational Frameworks Aimed at Preventing or Mitigating Drug Shortages in 28 European and Western Asian Countries

    Science.gov (United States)

    Bochenek, Tomasz; Abilova, Vafa; Alkan, Ali; Asanin, Bogdan; de Miguel Beriain, Iñigo; Besovic, Zeljka; Vella Bonanno, Patricia; Bucsics, Anna; Davidescu, Michal; De Weerdt, Elfi; Duborija-Kovacevic, Natasa; Fürst, Jurij; Gaga, Mina; Gailīte, Elma; Gulbinovič, Jolanta; Gürpınar, Emre U.; Hankó, Balázs; Hargaden, Vincent; Hotvedt, Tor A.; Hoxha, Iris; Huys, Isabelle; Inotai, Andras; Jakupi, Arianit; Jenzer, Helena; Joppi, Roberta; Laius, Ott; Lenormand, Marie-Camille; Makridaki, Despina; Malaj, Admir; Margus, Kertu; Marković-Peković, Vanda; Miljković, Nenad; de Miranda, João L.; Primožič, Stanislav; Rajinac, Dragana; Schwartz, David G.; Šebesta, Robin; Simoens, Steven; Slaby, Juraj; Sović-Brkičić, Ljiljana; Tesar, Tomas; Tzimis, Leonidas; Warmińska, Ewa; Godman, Brian

    2018-01-01

    Drug shortages have been identified as a public health problem in an increasing number of countries. This can negatively impact on the quality and efficiency of patient care, as well as contribute to increases in the cost of treatment and the workload of health care providers. Shortages also raise ethical and political issues. The scientific evidence on drug shortages is still scarce, but many lessons can be drawn from cross-country analyses. The objective of this study was to characterize, compare, and evaluate the current systemic measures and legislative and organizational frameworks aimed at preventing or mitigating drug shortages within health care systems across a range of European and Western Asian countries. The study design was retrospective, cross-sectional, descriptive, and observational. Information was gathered through a survey distributed among senior personnel from ministries of health, state medicines agencies, local health authorities, other health or pharmaceutical pricing and reimbursement authorities, health insurance companies and academic institutions, with knowledge of the pharmaceutical markets in the 28 countries studied. Our study found that formal definitions of drug shortages currently exist in only a few countries. The characteristics of drug shortages, including their assortment, duration, frequency, and dynamics, were found to be variable and sometimes difficult to assess. Numerous information hubs were identified. Providing public access to information on drug shortages to the maximum possible extent is a prerequisite for performing more advanced studies on the problem and identifying solutions. Imposing public service obligations, providing the formal possibility to prescribe unlicensed medicines, and temporary bans on parallel exports are widespread measures. A positive finding of our study was the identification of numerous bottom-up initiatives and organizational frameworks aimed at preventing or mitigating drug shortages. The

  17. Effect of olive waste (Husk on behavior of cement paste

    Directory of Open Access Journals (Sweden)

    Sharaf Alkheder

    2016-12-01

    Full Text Available Jordan is a famous country in terms of olive trees agriculture that resulted in a mass production of olive oil products. The huge amounts of olive waste (husk that resulted from olives processing to produce olive oil represent an environmental challenge in the country. The idea in this paper comes to use olive waste as a partial replacement for Portland cement in cement paste to conserve the environment, reduce cement consumption and increase cost efficiency. The wastes were burned properly in an oven and maintained for 6 h until it was fully transformed into ashes. Then, the oven was turned off and ashes were allowed to cool. After cooling, the material passed sieve #200 were used. The sieved ashes were used in the cement mix as a partial cement replacement for making the mortar and cement paste. Normal consistency and setting time were determined as well as soundness, compressive strength. Results indicated that normal consistency of the cement pastes containing different percentage of olive waste is somehow lower than that of the ordinary cement paste and slightly decreases with increasing the percentage. The results also indicated that the compressive strength of hardened blended cement paste containing different percentages of olive waste slightly decrease with olive waste content at 3, 7, and 28 days.

  18. The contemporary cement cycle of the United States

    Science.gov (United States)

    Kapur, A.; Van Oss, H. G.; Keoleian, G.; Kesler, S.E.; Kendall, A.

    2009-01-01

    A country-level stock and flow model for cement, an important construction material, was developed based on a material flow analysis framework. Using this model, the contemporary cement cycle of the United States was constructed by analyzing production, import, and export data for different stages of the cement cycle. The United States currently supplies approximately 80% of its cement consumption through domestic production and the rest is imported. The average annual net addition of in-use new cement stock over the period 2000-2004 was approximately 83 million metric tons and amounts to 2.3 tons per capita of concrete. Nonfuel carbon dioxide emissions (42 million metric tons per year) from the calcination phase of cement manufacture account for 62% of the total 68 million tons per year of cement production residues. The end-of-life cement discards are estimated to be 33 million metric tons per year, of which between 30% and 80% is recycled. A significant portion of the infrastructure in the United States is reaching the end of its useful life and will need to be replaced or rehabilitated; this could require far more cement than might be expected from economic forecasts of demand for cement. ?? 2009 Springer Japan.

  19. Screening for depression and anxiety among older Chinese immigrants living in Western countries: The use of the Geriatric Depression Scale (GDS) and the Geriatric Anxiety Inventory (GAI).

    Science.gov (United States)

    Lin, Xiaoping; Haralambous, Betty; Pachana, Nancy A; Bryant, Christina; LoGiudice, Dina; Goh, Anita; Dow, Briony

    2016-03-01

    Depression and anxiety are two common mental health problems among older people. There is evidence that using well-validated screening tools can improve detection of depression and anxiety among this group. The review explored the use of the Geriatric Depression Scale (GDS) and the Geriatric Anxiety Inventory (GAI) for screening depression and anxiety among older Chinese immigrants, one of the largest and fastest growing groups of older immigrants in Western society. It focused on the GDS and GAI because both are designed specifically for older people. Online literature searches were conducted in MEDLINE, CINAHL, and PsycINFO. A narrative approach was used to review included papers. A total of 21 articles were included. There were limited data on anxiety among older Chinese immigrants, with only one unpublished report identified. There were 13 studies (20 articles) using the GDS with this group. Results of these studies indicated that the GDS is a reliable tool in this population; however, there was limited validity data. Two versions of the GDS-15 have been used with older Chinese immigrants, including the standard GDS-15 and Mui's GDS-15. Prevalence of depression ranged between 20% and 30% in most reviewed studies. Results of this review have practical implications for clinicians in their use of these tools with older Chinese immigrants in Western countries, such as the different GDS versions. It also suggests a number of directions for future research, such as the inclusion of clinical samples and consideration of the diversity within this group. © 2015 Wiley Publishing Asia Pty Ltd.

  20. A systematic review of issues around antenatal screening and prenatal diagnostic testing for genetic disorders: women of Asian origin in western countries.

    Science.gov (United States)

    Yu, Juping

    2012-07-01

    Antenatal screening has become standard practice in many countries. However, not all pregnant women choose to be tested. In the UK, the incidence of some birth defects is found to be higher in babies of Asian women than in those of women from other ethnic groups, while there is some evidence suggesting that ethnic minorities, especially Asian women, are less likely to undergo antenatal screening and prenatal diagnosis, the reasons for which are unclear. This study aims to identify and describe the literature on issues around antenatal screening and prenatal diagnostic testing for genetic disorders among women of Asian descent in western countries. The Medline, CINAHL, ASSIA and PsycInfo databases were searched for the period of 1995 and 2010. Twenty-one studies met the inclusion criteria and were therefore reviewed. In general, Asian women were found to hold favourable attitudes towards testing. However, they reported a poorer understanding of testing than white women and not being offered a test, and were less able to make informed choices. Asian women in the UK and Australia were found to be less likely than their white counterparts to have undergone prenatal diagnosis, while such differences were not found in the USA and Canada. The equity of access to quality antenatal care, alongside comprehensive well thought out antenatal screening programmes, can be assured if strategies are in place which actively involve all ethnic groups and take account of social and cultural appropriateness for the population served. An understanding of broad factors that inform women's decision-making on test uptake would help health professionals provide women and their families with more culturally sensitive information and support that they may additionally need to make more informed choices. © 2011 Blackwell Publishing Ltd.

  1. Retention of crowns cemented on implant abutments with temporary cements.

    Science.gov (United States)

    Nagasawa, Yuko; Hibino, Yasushi; Nakajima, Hiroshi

    2014-01-01

    This study was to examine the retentive force of crowns to implant abutments with commercial temporary cements. Six different temporary cements were investigated. Cast crowns were cemented to the abutments using each cement and their retentive forces to abutments were determined 7 or 28 days after cementing (n=10). The retentive force of the cements to abutments varied widely among the products [27-109 N (7-day), 18-80 N (28-days)]. The retentive force of all the cements was not reduced as the time elapsed, except for two products tested. The polycarboxylate cements and paste-mixing type eugenol-free cements revealed comparable retentive force after 28 days of storage. The powder-liquid type cements showed a positive correlation (pcement between the retentive force and compressive strength. Mechanical strength of temporary cements could not be a prominent predicting factor for retention of the crowns on the abutments.

  2. Peritoneal Dialysis in Western Countries

    NARCIS (Netherlands)

    Struijk, Dirk G.

    2015-01-01

    Peritoneal dialysis (PD) for the treatment of end-stage renal failure was introduced in the 1960s. Nowadays it has evolved to an established therapy that is complementary to hemodialysis (HD), representing 11% of all patients treated worldwide with dialysis. Despite good clinical outcomes and

  3. Magnesium oxychloride cement concrete

    Indian Academy of Sciences (India)

    TECS

    are available all over the world. The cement is affected by excessive exposure to moisture, particularly at high temperatures. Use of various additives has been suggested to enhance the durability of this cement. (Bludnov et al 1974; Paul 1975; Mingfen and Wei 1989;. Misra and Mathur 1993; Chandrawat and Yadav 2000).

  4. Advanced cementation concepts

    International Nuclear Information System (INIS)

    Howard, C.G.

    1989-10-01

    The purpose of this programme of work was to investigate whether improvements could be made to existing formulations for cement suitable for the immobilization of intermediate level radioactive waste. Two additives were selected, microsilica and limestone flour. Improvements to the cement were only slight. (author)

  5. Assessment of radon and thoron exhalation from Indian cement samples using smart radon and thoron monitors

    International Nuclear Information System (INIS)

    Sahoo, B.K.; Sapra, B.K; Agarwal, T.K.; Babu, D.A.R.

    2015-01-01

    It has been established that primarily, there exist two important sources that contribute to indoor radon/thoron namely, the exhalation from ground and building materials. The contribution from ground, although significant, is treated as a case of existing exposure. Then, the only source that can be controlled during the construction is the choice of building materials. Cement is an important building material used in the construction of houses and buildings in India. The housing sector is the largest cement consumer with 53% of the total Indian cement demand followed by the infrastructure sector. India with a production capacity of 165 million tones (MT) (in 2007), was the second largest cement producer in the world after China. The industry produces various types of cement like ordinary portland cement (OPC), Portland pozzolana cement (PPC), portland slag cement (PSC), rapid hardening portland cement (RHPC), sulphate resistant cement (SRC) and white cement (WC). Several studies have been undertaken on cement in various countries because it is commonly used in bulk quantities in the construction of houses and other civil structures. However, detailed information regarding the radon and thoron exhalation into indoor air from various types of cements produced in India is scarce. In the present work, an attempt has been made to systematically determine the radon and thoron exhalation from 50 cement samples (17 OPC, 15 PPC, 04 PSC, 06 RHPC, 04 WC and 04 SRC). The data thus obtained is used to calculate the indoor radon and thoron source term and the contributed inhalation dose based on a model room structure. The measured values of radon and thoron exhalation from cement samples were comparable with the reported values in other countries. This study showed that the cement samples used in civil constructions do not pose any radiological hazard to the Indian population. (author)

  6. Cement composite delivery system.

    Science.gov (United States)

    Convery, F R; Devine, S D; Hollis, J M; Woo, S L

    1986-09-01

    Several new and innovative techniques have recently been introduced that purport to increase the strength of polymethyl methacrylate bone cement. One of these concepts is the use of carbon and polymer fibers to form a cement composite. Bone cement composites usually 1% fiber, are very difficult to use clinically. The composite is very sticky and viscous, which precludes effective hand packing or the use of conventional delivery systems. A new delivery system for very viscous materials is presented and examples of in vitro application are shown.

  7. Energy optimization and reduction of carbon footprint in cement manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Gallestey, Eduardo; Crosley, Gabriela; Wilson, Andrew; Maier, Urs; Hoppler, Rolf; Boerrnert, Thomas

    2010-09-15

    Cement producers are large consumers of thermal and electrical energy, which are only available at steadily increasing costs. Efforts to reduce demands by using higher efficiency equipment and substituting -fuels and raw materials to lower production costs have been addressed in recent years. Under the Kyoto Protocol industrialised countries agreed to reduce their collective greenhouse gas emissions. Cement producers as some of the largest emitters of CO2 have been especially challenged to find new and innovative ways to reduce greenhouse gas emissions. This paper summarise some ABB technologies developed to assist the cement industry to meet these goals.

  8. Barnacle cement: a polymerization model based on evolutionary concepts

    Science.gov (United States)

    Dickinson, Gary H.; Vega, Irving E.; Wahl, Kathryn J.; Orihuela, Beatriz; Beyley, Veronica; Rodriguez, Eva N.; Everett, Richard K.; Bonaventura, Joseph; Rittschof, Daniel

    2009-01-01

    Summary Enzymes and biochemical mechanisms essential to survival are under extreme selective pressure and are highly conserved through evolutionary time. We applied this evolutionary concept to barnacle cement polymerization, a process critical to barnacle fitness that involves aggregation and cross-linking of proteins. The biochemical mechanisms of cement polymerization remain largely unknown. We hypothesized that this process is biochemically similar to blood clotting, a critical physiological response that is also based on aggregation and cross-linking of proteins. Like key elements of vertebrate and invertebrate blood clotting, barnacle cement polymerization was shown to involve proteolytic activation of enzymes and structural precursors, transglutaminase cross-linking and assembly of fibrous proteins. Proteolytic activation of structural proteins maximizes the potential for bonding interactions with other proteins and with the surface. Transglutaminase cross-linking reinforces cement integrity. Remarkably, epitopes and sequences homologous to bovine trypsin and human transglutaminase were identified in barnacle cement with tandem mass spectrometry and/or western blotting. Akin to blood clotting, the peptides generated during proteolytic activation functioned as signal molecules, linking a molecular level event (protein aggregation) to a behavioral response (barnacle larval settlement). Our results draw attention to a highly conserved protein polymerization mechanism and shed light on a long-standing biochemical puzzle. We suggest that barnacle cement polymerization is a specialized form of wound healing. The polymerization mechanism common between barnacle cement and blood may be a theme for many marine animal glues. PMID:19837892

  9. Fabrication of Phosphate Cement with High Integrity

    International Nuclear Information System (INIS)

    Yang, Jae Hwan; Lee, Chang Hwa; Heo, Cheol Min; Jeon, Min Ku; Kang, Kweon Ho

    2011-01-01

    As the development of industrial society has accelerated, hazardous wastes are generated as well. According to the 1986 statistics of U.S.A, each person made 40 tons of waste in America that year. Treatment of radioactive waste is one of the most important and serious problems related to waste treatments, because its radioactivity and decaying heat have harmful effects to human and environment for a long time. Nuclear developed countries have used conventional method of treatment such as vitrification or cementation in order to stabilize and solidify radioactive waste. Although the former guarantees the formation of high leaching resistant and durable waste form, it requires several hundred (or even more than one thousand) temperature to melt glass frit. This process generates secondary waste volatilized, as well as being non-economical. Cement technology played a role of immobilizing low and middle class wastes. It has advantages of low temperature setting, low cost, easy process, etc. The alkalinity of ordinary cement, however, constrains the utility of cement to the solidification of alkaline waste. In addition, leachability and mechanical strength of cements are not quite appropriate for the stabilization of high level waste. In this regard, chemically bonded phosphate cement(CBPC), which sets by an acid-base reaction, is a potentially expectable material for immobilization of radioactive waste. CBPC not only sets at room temperature, but also encapsulates various isotopes chemically. The performance of CBPC can be enhanced by the addition of fly ash, sand, wollastonite, etc. This study aims at fabricating the CBPC containing fly ash with high integrity. Morphology, microstructure, and compressive strength are evaluated using SEM, and digital compressing machine

  10. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2001-10-23

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). Work reported herein addresses tasks performed in the fourth quarter as well as the other three quarters of the past year. The subjects that were covered in previous reports and that are also discussed in this report include: Analysis of field laboratory data of active cement applications from three oil-well service companies; Preliminary findings from a literature review focusing on problems associated with ultra-lightweight cements; Summary of pertinent information from Russian ultra-lightweight cement literature review; and Comparison of compressive strengths of ULHS systems using ultrasonic and crush methods Results reported from the fourth quarter include laboratory testing of ULHS systems along with other lightweight cement systems--foamed and sodium silicate slurries. These comparison studies were completed for two different densities (10.0 and 11.5 lb/gal) and three different field application scenarios. Additional testing included the mechanical properties of ULHS systems and other lightweight systems. Studies were also performed to examine the effect that circulation by centrifugal pump during mixing has on breakage of ULHS.

  11. Human papillomavirus prevalence and type-distribution, cervical cancer screening practices and current status of vaccination implementation in Russian Federation, the Western countries of the former Soviet Union, Caucasus region and Central Asia.

    Science.gov (United States)

    Rogovskaya, Svetlana I; Shabalova, Irina P; Mikheeva, Irina V; Minkina, Galina N; Podzolkova, Nataly M; Shipulina, Olga Y; Sultanov, Said N; Kosenko, Iren A; Brotons, Maria; Buttmann, Nina; Dartell, Myassa; Arbyn, Marc; Syrjänen, Stina; Poljak, Mario

    2013-12-31

    Limited data are available on the burden of human papillomavirus (HPV) and its associated diseases in the Russian Federation, the Western Countries of the former Soviet Union (Belarus, Republic of Moldova, Ukraine), the Caucasus region and Central Asia (Armenia, Azerbaijan, Georgia, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, Uzbekistan). Both the incidence and mortality rate of cervical cancer are higher in these countries than in most Western European countries. In this article, we review available data on HPV prevalence and type distribution in women with normal cytology, women from the general population, cervical precancerous lesions and cervical cancer, as well as data on national policies of cervical cancer screening and HPV vaccination initiatives in these countries. Based on scarce data from the 12 countries, the high-risk HPV (hrHPV) prevalence among 5226 women with normal cytology ranged from 0.0% to 48.4%. In women with low-grade cervical lesions, the hrHPV prevalence among 1062 women varied from 29.2% to 100%. HrHPV infection in 565 women with high-grade cervical lesions ranged from 77.2% to 100% and in 464 invasive cervical cancer samples from 89.8% to 100%. HPV16 was the most commonly detected hrHPV genotype in all categories. As the HPV genotype distribution in cervical diseases seems to be similar to that found in Western Europe the implementation of HPV testing in screening programs might be beneficial. Opportunistic screening programs, the lack of efficient call-recall systems, low coverage, and the absence of quality assured cytology with centralized screening registry are major reasons for low success rates of cervical cancer programs in many of the countries. Finally, HPV vaccination is currently not widely implemented in most of the twelve countries mainly due to pricing, availability, and limited awareness among public and health care providers. Country-specific research, organized nationwide screening programs, registries and well

  12. Internal globalization of Western Balkan

    Directory of Open Access Journals (Sweden)

    Vukotić Veselin

    2006-01-01

    Full Text Available What are potential and real effects of the globalization process on the economic connection between Western Balkan countries? What is the crucial change in relations between Western Balkan countries and its economies inexorably brought by globalization? What are the elements of political economy of Western Balkan globalization? What are reflections of the conflict between political and economic areas of Western Balkan? These are some of the issues discuses in this paper.

  13. Technology Roadmaps: Cement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    To support its roadmap work focusing on key technologies for emissions reductions, the International Energy Agency (IEA) also investigated one particular industry: cement. Cement production includes technologies that are both specific to this industry and those that are shared with other industries (e.g., grinding, fuel preparation, combustion, crushing, transport). An industry specific roadmap provides an effective mechanism to bring together several technology options. It outlines the potential for technological advancement for emissions reductions in one industry, as well as potential cross-industry collaboration.

  14. Cementation of liquid radioactive waste

    International Nuclear Information System (INIS)

    Efremenkov, V.

    2004-01-01

    The cementation methods for immobilisation of radioactive wastes are discussed in terms of methodology, chemistry and properties of the different types of cements as well as the worldwide experience in this field. Two facilities for cementation - DEWA and MOWA - are described in details

  15. Center for Cement Composite Materials

    Science.gov (United States)

    1990-01-31

    DSP cement pastes were prepared using white Portland cement (PC), amorphous silica fume, and a superplasticizer . The fume/cement ratios varied from... superplasticized PC pastes without silica fume. This is due to a reduction in the amount and size of porosity formed in DSP. Specific: surface areas measured

  16. Reducing cement's CO2 footprint

    Science.gov (United States)

    van Oss, Hendrik G.

    2011-01-01

    The manufacturing process for Portland cement causes high levels of greenhouse gas emissions. However, environmental impacts can be reduced by using more energy-efficient kilns and replacing fossil energy with alternative fuels. Although carbon capture and new cements with less CO2 emission are still in the experimental phase, all these innovations can help develop a cleaner cement industry.

  17. Cementing a wellbore using cementing material encapsulated in a shell

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Spadaccini, Christopher M.; Cowan, Kenneth Michael

    2016-08-16

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in the space between the wellbore and the pipe.

  18. Cementing a wellbore using cementing material encapsulated in a shell

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Floyd, III, William C.; Spadaccini, Christopher M.; Vericella, John J.; Cowan, Kenneth Michael

    2017-03-14

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in the space between the wellbore and the pipe.

  19. The mechanical effect of the existing cement mantle on the in-cement femoral revision.

    LENUS (Irish Health Repository)

    Keeling, Parnell

    2012-08-01

    Cement-in-cement revision hip arthroplasty is an increasingly popular technique to replace a loose femoral stem which retains much of the original cement mantle. However, some concern exists regarding the retention of the existing fatigued and aged cement in such cement-in-cement revisions. This study investigates whether leaving an existing fatigued and aged cement mantle degrades the mechanical performance of a cement-in-cement revision construct.

  20. Prevalence and Social Determinants of Smoking in 15 Countries from North Africa, Central and Western Asia, Latin America and Caribbean: Secondary Data Analyses of Demographic and Health Surveys.

    Science.gov (United States)

    Sreeramareddy, Chandrashekhar T; Pradhan, Pranil Man Singh

    2015-01-01

    Article 20 of the World Health Organisation Framework Convention on Tobacco Control calls for a cross-country surveillance of tobacco use through population-based surveys. We aimed to provide country-level prevalence estimates for current smoking and current smokeless tobacco use and to assess social determinants of smoking. Data from Demographic and Health Surveys done between 2005 and 2012, among men and women from nine North African, Central and West Asian countries and six Latin American and Caribbean countries were analyzed. Weighted country-level prevalence rates were estimated for 'current smoking' and 'current use of smokeless tobacco (SLT) products' among men and women. In each country, social determinants of smoking among men and women were assessed by binary logistic regression analyses by including men's and women's sampling weights to account for the complex survey design. Prevalence of smoking among men was higher than 40% in Armenia (63.1%), Moldova (51.1%), Ukraine (52%), Azerbaijan (49.8 %), Kyrgyz Republic (44.3 %) and Albania (42.52%) but the prevalence of smoking among women was less than 10% in most countries except Ukraine (14.81%) and Jordan (17.96%). The prevalence of smokeless tobacco use among men and women was less than 5% in all countries except among men in the Kyrgyz Republic (10.6 %). Smoking was associated with older age, lower education and poverty among men and higher education and higher wealth among women. Smoking among both men and women was associated with unskilled work, living in urban areas and being single. Smoking among men was very high in Central and West Asian countries. Social pattern of smoking among women that was different from men in education and wealth should be considered while formulating tobacco control policies in some Central and West Asian countries.

  1. EVALUATION OF CHEMICALS INCORPORATED WOOD FIBRE CEMENT MATRIX PROPERTIES

    Directory of Open Access Journals (Sweden)

    MST. SADIA MAHZABIN

    2013-08-01

    Full Text Available Wood fibre cement (WFC boards are well established commercially and widely used in many developed countries. The combination of the properties of two important materials, i.e., cement, and previously treated fibrous materials like wood or agricultural residues; which made up the board, contributed in the performance of the board as building material. In this work, the WFC matrix (WFCM samples are produced to determine the physical properties of WFCM such as the density and water absorption. The wood fibres are incorporated/treated with three different chemical additives; calcium formate (Ca(HCOO2, sodium silicate (Na2.SiO3 and magnesium chloride (MgCl2 prior to mixing with cement. The mechanical properties of the WFCM, with or without chemicals treatment of fibres, such as the compressive strength and flexural strength are evaluated. Three wood/cement ratios (50:50, 40:60, 30:70 are used and the percentages of water and accelerator were 80% and 3% based on the cement weight, respectively. Three moisture-conditioned samples; accelerated aging, dry and wet conditions are used for flexural test. The results reveal that the wood/cement ratio, chemical additives and moisture content had a marked influence on the physical and mechanical properties of the matrix. Finally, it has been shown that the 40:60 wood/cement ratio samples with prior chemicals treatment of the fibres that undergo accelerated aging conditioning achieve higher strength then dry and wet-conditioned boards.

  2. Chest radiological findings in pakistani cement mill workers

    International Nuclear Information System (INIS)

    Meo, Sultan A.

    2003-01-01

    Chest radiological findings in Pakistani cement mill workers Even in the 21st century, in developing countries millions of people work daily in dusty environments. They are exposed to different types of health hazards namely, fumes, gases and dust, which are risk factors for developing occupational diseases. Therefore, the aim of this study was to perform chest radiology to determine the occupational hazards of cement dust on the lungs of cement mill workers. This study was carried out in the Department of Physiology, Faculty of Health and Medical Sciences, Hamdard University Karachi, Pakistan, during the period June to August 2000. In this study 50, apparently healthy volunteer male cement mill workers were randomly selected with an average of 13 years exposure with age ranging from 20-60 years. They were matched with 50, healthy male control subjects in terms of age, height, weight and socioeconomic status. Both groups met with exclusion criteria as per standard. Radiology was performed by Trophy radiology. Results: The present study demonstrated 12% of cases with interstitial lung disease and 2% of cases with pleural thickening and chronic bronchitis in cement mill workers. Conclusion: Exposure to cement dust causes interstitial lung disease, pleural thickening and chronic bronchitis in cement mill workers. (author)

  3. Blood donation barriers and facilitators of Sub-Saharan African migrants and minorities in Western high-income countries: a systematic review of the literature

    NARCIS (Netherlands)

    Klinkenberg, E. F.; Huis In 't Veld, E. M. J.; de Wit, P. D.; van Dongen, A.; Daams, J. G.; de Kort, W. L. A. M.; Fransen, M. P.

    2018-01-01

    The present study aimed to gain more insight into, and summarise, blood donation determinants among migrants or minorities of Sub-Saharan heritage by systematically reviewing the current literature. Sub-Saharan Africans are under-represented in the blood donor population in Western high-income

  4. Retention, marginal leakage, and cement solubility of provisional crowns cemented with temporary cement containing stannous fluoride.

    Science.gov (United States)

    Lewinstein, Israel; Fuhrer, Nitzan; Gelfand, Katerina; Cardash, Harold; Pilo, Raphael

    2003-01-01

    This in vitro study investigated the (1) retention and microleakage of provisional crowns cemented with temporary cements to which stannous fluoride (SnF2) was added, and (2) solubility of these cements. Provisional crowns were constructed of acrylic resin with shoulder preparations for 12 molars. The crowns were luted with Tempbond, Tempbond NE, and Freegenol temporary cements, and also with SnF2 added to these cements. Specimens were thermocycled 100 times, stored for 6 days, and immersed in 0.5% basic fuschin. Seven days after cementation, crown removal (retention) tests were conducted. Marginal leakage was assessed using a five-level scale to score dye penetration. Solubility in water of the cements with and without SnF2 was assessed using cement disks. Freegenol was more retentive than the other cements. The incorporation of SnF2 significantly increased the retention capacity of Freegenol and Tempbond NE but had no effect on Tempbond. Tempbond showed significantly higher dye penetration than Freegenol. The addition of SnF2 did not alter the dye penetration of the cements. There were no significant differences in the solubility of the cements. However, the incorporation of SnF2 increased the solubility of Freegenol and Tempbond NE (P crowns cemented with Tempbond NE and Freegenol but did not affect the retention of those cemented with Tempbond. The marginal leakage of crowns cemented with the tested temporary cements with and without the incorporation of SnF2 was similar. However, the addition of SnF2 increased the solubility of the cements.

  5. Magnesium oxychloride cement concrete

    Indian Academy of Sciences (India)

    TECS

    ting. It is used in industrial floorings, ship decks, railway passenger coach floorings, hospital floors, ammunition factory floors, missile silos and underground armament factories and bunkers. Recently, concrete of high compres- sive and tensile strength prepared with magnesium oxy- chloride cement and recycled rubber ...

  6. Cement manufacture and the environment - Part I: Chemistry and technology

    Science.gov (United States)

    Van Oss, H. G.; Padovani, A.C.

    2002-01-01

    Hydraulic (chiefly portland) cement is the binding agent in concrete and mortar and thus a key component of a country's construction sector. Concrete is arguably the most abundant of all manufactured solid materials. Portland cement is made primarily from finely ground clinker, which itself is composed dominantly of hydraulically active calcium silicate minerals formed through high-temperature burning of limestone and other materials in a kiln. This process requires approximately 1.7 tons of raw materials perton of clinker produced and yields about 1 ton of carbon dioxide (CO2) emissions, of which calcination of limestone and the combustion of fuels each contribute about half. The overall level of CO2 output makes the cement industry one of the top two manufacturing industry sources of greenhouse gases; however, in many countries, the cement industry's contribution is a small fraction of that from fossil fuel combustion by power plants and motor vehicles. The nature of clinker and the enormous heat requirements of its manufacture allow the cement industry to consume a wide variety of waste raw materials and fuels, thus providing the opportunity to apply key concepts of industrial ecology, most notably the closing of loops through the use of by-products of other industries (industrial symbiosis). In this article, the chemistry and technology of cement manufacture are summarized. In a forthcoming companion article (part II), some of the environmental challenges and opportunities facing the cement industry are described. Because of the size and scope of the U.S. cement industry, the analysis relies primarily on data and practices from the United States.

  7. Use of alternative fuels in the Polish cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Mokrzycki, Eugeniusz; Uliasz-Bochenczyk, Alicja [Polish Academy of Sciences, Mineral and Energy Economy Research Inst., Krakow (Poland); Sarna, Mieczyslaw [Lafarge Cement Polska S.A., Malogoszcz (Poland)

    2003-02-01

    Alternative fuels are made up of mixtures of different wastes, such as industrial, municipal and hazardous wastes. These fuels need to have an appropriate chemical energy content which depends on the type of components and their organic content. An industry that is particularly well suited to the employment of alternative fuels is the cement industry. There are a number of factors that promote the use of alternative fuels in cement kilns. Of these factors, the most notable are: the high temperatures developed, the appropriate kiln length, the long period of time the fuel stays inside the kiln and the alkaline environment inside the kiln. There are a number of countries that use their own alternative fuels in cement plants. These fuels have different trade names and they differ in the amounts and the quality of the selected municipal and industrial waste fractions used. The fuels used should fall within the extreme values of parameters such as: minimum heating value, maximum humidity content, and maximum content of heavy and toxic metals. Cement plants in Poland also use alternative fuels. Within the Lafarge Group, the cement plants owned by Lafarge Poland Ltd. have initiated activities directed at promoting the wider use of alternative fuels. There are a number of wastes that can be incinerated as fuel in cement plants. Some that can be mentioned are: selected combustible fractions of municipal wastes, liquid crude-oil derived wastes, car tyres, waste products derived from paint and varnish production, expired medicines from the pharmaceutical industry and others. The experience gained by the cement plants of Lafarge Cement Poland Ltd confirms that such activities are economically and ecologically beneficial. The incineration of alternative fuels in cement plants is a safe method for the utilisation of waste that is ecologically friendly and profitable for the industrial plants and society alike. (Author)

  8. First forum ''BISE'' for: the intelligent energy in the municipalities and the new member states, of candidate countries and western Balkans

    International Nuclear Information System (INIS)

    2004-01-01

    The european commission and the european association of municipalities (Energie Cites) established a permanent ''Intelligent Energy Forum of European Municipalities'' (named BISE Forum) as form of periodical information exchange between municipal associations and other potential partners in Europe. In the framework of the reduction of the sustainable energy gap between the Central and Eastern European Countries and the most advanced energy-efficient EU 15 countries, the aim of this forum is to promote the creation of national energy cities networks, to integrate the initiatives and networks at an European scale and to promote the idea of an European Emergency Plan in order to improve energy efficiency in Eastern European Countries as quickly as possible. This document presents the proceedings and a selection of cases studies linked to the first BISE Forum. (A.L.B.)

  9. INORGANIC CEMENT CONCRETE

    Directory of Open Access Journals (Sweden)

    Alisson Clay Rios Silva

    2014-07-01

    Full Text Available In this work, a Geopolymeric Cement Concrete (GCC was developed through adequate portions of geopolymer components. Its characteristics were compared with Portland Cement Concrete (PCC, through of the establishment of some parameters of design, as consumption of binders, water/aggregates ratio and mortar content. The concrete mechanical performance was evaluated with emphasis to the fatigue behavior. Were tested the effects of different tensile strength maximum (increasing and decreasing. The results of fatigue tests had shown that GCC presents a better performance when compared to PCC. Its fatigue strength was 15% higher than that of PCC, when 70% of rupture tension of the concrete in static bending (SR, was applied. Tensions of about 80% SR resulted in 96% of increase, when compared to GCC. The SEM microstructural analysis showed that the GCC has a matrix/aggregate bonding very strong, when compared to PCC, probably due to the massive nature of the geopolymeric matrix.

  10. Performance of Cement Containing Laterite as Supplementary Cementing Material

    Directory of Open Access Journals (Sweden)

    Abbas Bukhari, Z. S.

    2013-03-01

    Full Text Available The utilization of different industrial waste, by-products or other materials such as ground granulated blast furnace slag, silica fume, fly ash, limestone, and kiln dust, etc. as supplemen- tary cementing materials has received considerable attention in recent years. A study has been conducted to look into the performance of laterite as Supplementary Cementing Materials (SCM. The study focuses on compressive strength performance of blended cement containing different percentage of laterite. The cement is replaced accordingly with percentage of 2 %, 5 %, 7 % and 10 % by weight. In addition, the effect of use of three chemically different laterites have been studied on physical performance of cement as in setting time, Le-Chatlier expansion, loss on ignition, insoluble residue, free lime and specifically compressive strength of cement cubes tested at the age of 3, 7, and 28 days. The results show that the strength of cement blended with laterite as SCM is enhanced. Key words: Portland cement, supplementary cementing materials (SCM, laterite, compressive strength KUI – 6/2013 Received January 4, 2012 Accepted February 11, 2013

  11. Activity of oritavancin against methicillin-resistant staphylococci, vancomycin-resistant enterococci and β-haemolytic streptococci collected from western European countries in 2011.

    Science.gov (United States)

    Morrissey, Ian; Seifert, Harald; Canton, Rafael; Nordmann, Patrice; Stefani, Stefania; Macgowan, Alasdair; Janes, Regina; Knight, Daniel

    2013-01-01

    To determine the activity of oritavancin against methicillin-resistant staphylococci, vancomycin-resistant enterococci (VRE) and β-haemolytic streptococci recently isolated from acute bacterial skin and skin structure infections or bacteraemia in western Europe. Forty-one centres in Spain (8), Italy (9), Germany (8), France (8) and the UK (8) submitted 866 isolates [204 methicillin-resistant Staphylococcus aureus (MRSA), 177 methicillin-resistant coagulase-negative staphylococci (MRCoNS), 101 VRE, 193 Streptococcus agalactiae and 191 Streptococcus pyogenes] that were collected during the first 6 months of 2011. These were re-identified and susceptibilities to oritavancin and comparators were determined. Oritavancin was very active against MRSA (MIC(50)/MIC(90) 0.03/0.06 mg/L), MRCoNS (0.06/0.12 mg/L), VRE (0.03/0.06 mg/L), S. agalactiae (0.03/0.06 mg/L) and S. pyogenes (0.06/0.25 mg/L). The highest oritavancin MIC observed was 0.25 mg/L (species were S. aureus, Staphylococcus epidermidis, Staphylococcus hominis, S. agalactiae, S. pyogenes and Enterococcus faecalis). These data from recently collected Gram-positive bacteria in western Europe confirm the potent in vitro activity of oritavancin against a wide range of resistant MRSA, MRCoNS and VRE isolates, including ones resistant to newer agents.

  12. Rheology of acrylic bone cements.

    Science.gov (United States)

    Ferracane, J L; Greener, E H

    1981-01-01

    The rheological properties of setting acrylic bone cements were examined with a rotational cone and plate viscometer. The cements were tested over two orders of magnitude of shear rate to determine the nature of any non-Newtonian flow behavior. All three cements behaved with moderate pseudoplasticity (i.e., shear thinning) during setting, suggesting the use of higher pressures during administration for better flow and penetration. The low viscosity brand was found to be nearly one-half as viscous as the conventional cements during the working time (i.e., 2-5 minutes). A series of sieving experiments were performed to determine the particle size distributions of the powder components. Statistical analysis (chi square) showed the cements to have different distributions, with the low viscosity brand containing a larger proportion of smaller polymer particles. This difference is thought to contribute to the lower viscosity of this cement.

  13. properties of cement paste and concrete containing calcium carbide

    African Journals Online (AJOL)

    user

    2017-01-01

    Jan 1, 2017 ... The alternatives to conventional materials include use of pozzolanas as substitutes to cement or as mineral admixtures and use of other binders from agricultural wastes and by-products from industrial processes as admixtures or additives. In many developing countries the demand for building construction ...

  14. potentials of cement kiln dust in sub-grade improvement

    African Journals Online (AJOL)

    2013-03-01

    Mar 1, 2013 ... Abstract. The ever increasing cost of construction materials in Nigeria and other developing countries has created the need for research into locally and readily available materials and also on how to convert materials considered to be waste by-product such as cement kiln dust (CKD) for use in construction.

  15. Compressive Strength Of Rice Husk Ash-Cement Sandcrete Blocks ...

    African Journals Online (AJOL)

    There is growing demand for alternative, low-cost building material in developing countries. The effect of partial substitution of ordinary Portland cement with Rice Husk Ash (RHA) on the compressive strength of hollow sandcrete block was investigated through laboratory experimental procedures. The specific gravity, initial ...

  16. Coal Bottom Ash for Portland Cement Production

    Directory of Open Access Journals (Sweden)

    Cristina Argiz

    2017-01-01

    Full Text Available Because of industrialization growth, the amount of coal power plant wastes has increased very rapidly. Particularly, the disposal of coal bottom ash (CBA is becoming an increasing concern for many countries because of the increasing volume generated, the costs of operating landfill sites, and its potential hazardous effects. Therefore, new applications of coal bottom ash (CBA have become an interesting alternative to disposal. For instance, it could be used as a Portland cement constituent leading to more sustainable cement production by lowering energy consumption and raw material extracted from quarries. Coal fly and bottom ashes are formed together in the same boiler; however, the size and shape of these ashes are very different, and hence their effect on the chemical composition as well as on the mineralogical phases must be studied. Coal bottom ash was ground. Later, both ashes were compared from a physical, mechanical, and chemical point of view to evaluate the potential use of coal bottom ash as a new Portland cement constituent. Both ashes, produced by the same electrical power plant, generally present similar chemical composition and compressive strength and contribute to the refill of mortar capillary pores with the reaction products leading to a redistribution of the pore size.

  17. Association between forgone care and household income among the elderly in five Western European countries – analyses based on survey data from the SHARE-study

    Science.gov (United States)

    Mielck, Andreas; Kiess, Raphael; Knesebeck, Olaf von dem; Stirbu, Irina; Kunst, Anton E

    2009-01-01

    Background Studies on the association between access to health care and household income have rarely included an assessment of 'forgone care', but this indicator could add to our understanding of the inverse care law. We hypothesize that reporting forgone care is more prevalent in low income groups. Methods The study is based on the 'Survey of Health, Ageing and Retirement in Europe (SHARE)', focusing on the non-institutionalized population aged 50 years or older. Data are included from France, Germany, Greece, Italy and Sweden. The dependent variable is assessed by the following question: During the last twelve months, did you forgo any types of care because of the costs you would have to pay, or because this care was not available or not easily accessible? The main independent variable is household income, adjusted for household size and split into quintiles, calculating the quintile limits for each country separately. Information on age, sex, self assessed health and chronic disease is included as well. Logistic regression models were used for the multivariate analyses. Results The overall level of forgone care differs considerably between the five countries (e.g. about 10 percent in Greece and 6 percent in Sweden). Low income groups report forgone care more often than high income groups. This association can also be found in analyses restricted to the subsample of persons with chronic disease. Associations between forgone care and income are particularly strong in Germany and Greece. Taking the example of Germany, forgone care in the lowest income quintile is 1.98 times (95% CI: 1.08–3.63) as high as in the highest income quintile. Conclusion Forgone care should be reduced even if it is not justified by an 'objective' need for health care, as it could be an independent stressor in its own right, and as patient satisfaction is a strong predictor of compliance. These efforts should focus on population groups with particularly high prevalence of forgone care

  18. Utilisation of psychiatrists and psychologists in private practice among non-Western labour immigrants, immigrants from refugee-generating countries and ethnic Danes

    DEFF Research Database (Denmark)

    Nielsen, Signe Smith; Jensen, Natasja Koitzsch; Kreiner, Svend

    2015-01-01

    PURPOSE: The stressful migration process has been associated with higher vulnerability for mental health problems, implying a greater need for mental healthcare among immigrants compared with native-born. Our objective was to investigate whether potential differences in the use of psychiatrists...... and psychologists in labour immigrants, immigrants from refugee-generating countries (RGC), and ethnic Danes could be fully explained by mental health status. METHODS: We conducted a nationwide survey in 2007 with 3,573 individuals aged 18-66 comprising ethnic Danes, labour immigrants (Pakistan and Turkey...

  19. Thermal Shock-resistant Cement

    Energy Technology Data Exchange (ETDEWEB)

    Sugama T.; Pyatina, T.; Gill, S.

    2012-02-01

    We studied the effectiveness of sodium silicate-activated Class F fly ash in improving the thermal shock resistance and in extending the onset of hydration of Secar #80 refractory cement. When the dry mix cement, consisting of Secar #80, Class F fly ash, and sodium silicate, came in contact with water, NaOH derived from the dissolution of sodium silicate preferentially reacted with Class F fly ash, rather than the #80, to dissociate silicate anions from Class F fly ash. Then, these dissociated silicate ions delayed significantly the hydration of #80 possessing a rapid setting behavior. We undertook a multiple heating -water cooling quenching-cycle test to evaluate the cement’s resistance to thermal shock. In one cycle, we heated the 200 and #61616;C-autoclaved cement at 500 and #61616;C for 24 hours, and then the heated cement was rapidly immersed in water at 25 and #61616;C. This cycle was repeated five times. The phase composition of the autoclaved #80/Class F fly ash blend cements comprised four crystalline hydration products, boehmite, katoite, hydrogrossular, and hydroxysodalite, responsible for strengthening cement. After a test of 5-cycle heat-water quenching, we observed three crystalline phase-transformations in this autoclaved cement: boehmite and #61614; and #61543;-Al2O3, katoite and #61614; calcite, and hydroxysodalite and #61614; carbonated sodalite. Among those, the hydroxysodalite and #61614; carbonated sodalite transformation not only played a pivotal role in densifying the cementitious structure and in sustaining the original compressive strength developed after autoclaving, but also offered an improved resistance of the #80 cement to thermal shock. In contrast, autoclaved Class G well cement with and without Class F fly ash and quartz flour failed this cycle test, generating multiple cracks in the cement. The major reason for such impairment was the hydration of lime derived from the dehydroxylation of portlandite formed in the autoclaved

  20. Ghetto poverty and pollution in Egypt: a deadly threat for western countries caused by new and infectious mutants. A cultural, social and microbiological synopsis.

    Science.gov (United States)

    Wassili, J H; Baradaeus, Cyril

    2012-10-01

    Egypt, whose soil germinated the first civilization, monotheism, refined ethics and culture of sharing the abundance of extracted natural resources among its populace became the crucible proliferating de-novo genotypes of organic and moral maladies. The enigma is these mutations are synchronized by several factors, namely; failing medical health, if there is any, abundant filth, cultural bankruptcy, over population, dogmatic militarism, societal deprivation and characterization, etc. These domineering ingredients fossilized Egypt as of 1952 coup in an irrevocable national apoptosis, together with the crippled social justice and imbalanced distribution of wealth among Egyptians, rates of bacterial and viral evolution to second generation resistant to known medical interventions are expected to exponentially accelerate. Therefore, it deemed essential to elaborate on pollution and psychosis-induced inflammations and grievous crimes evoked by dogmatic cults at the breeding source, e.g., ghettos and sporadic locations of the homeless in Cairo, Alexandria and Upper Egyptian villages. While this second generation of viral and bacterial diseases could labor plagues threatening the precariously maintained so-called social fabric of Middle Eastern countries, that are uniquely segregating its populace according to their dogmatic affiliations and soaked into intolerance, it would definitely compromise the integrity of the expensively managed medical care system of developed countries.

  1. Health hazards of cement dust

    International Nuclear Information System (INIS)

    Meo, Sultan A.

    2004-01-01

    ven in the 21st century, millions of people are working daily in a dusty environment. They are exposed to different types of health hazards such as fume, gases and dust, which are risk factors in developing occupational disease. Cement industry is involved in the development of structure of this advanced and modern world but generates dust during its production. Cement dust causes lung function impairment, chronic obstructive lung disease, restrictive lung disease, pneumoconiosis and carcinoma of the lungs, stomach and colon. Other studies have shown that cement dust may enter into the systemic circulation and thereby reach the essentially all the organs of body and affects the different tissues including heart, liver, spleen, bone, muscles and hairs and ultimately affecting their micro-structure and physiological performance. Most of the studies have been previously attempted to evaluate the effects of cement dust exposure on the basis of spirometry or radiology, or both. However, collective effort describing the general effects of cement dust on different organ and systems in humans or animals, or both has not been published. Therefore, the aim of this review is to gather the potential toxic effects of cement dust and to minimize the health risks in cement mill workers by providing them with information regarding the hazards of cement dust. (author)

  2. Nuclear Energy in Western Europe: At the End of its Business Cycle? A review of policies in selected West European countries and Russia

    Energy Technology Data Exchange (ETDEWEB)

    Tangen, Kristian

    1997-12-31

    A series of seminars were held in Norway in 1995-97 focusing on nuclear energy policies, mainly in Europe. The key questions were: (1) What are the major driving forces behind the development of the nuclear industry?, and (2) Are we seeing the end of the nuclear energy era, or will we actually discover that the nuclear energy is moving towards its second blossom? This report summarizes the discussions at the seminars and discusses the above questions. The nature of the driving forces depends on the country in question. In France and Russia the nuclear sectors are large and prestigious and the course is difficult to change. In Germany and Sweden, political parties have adopted an anti-nuclear attitude and the issue is controversial, involving arguments both pro and con. The British nuclear sector has come to the end of the road. The main driving force has been the deregulation of the electricity market. In all countries, climate issues, independence from energy import, prestige and low costs have been arguments against close-downs. Massive expansion of nuclear power in Europe is unlikely. However, new plants might appear in Finland, Turkey or France. It is likely that technological development of the nuclear power sector, if any, will come in Asia. It is unclear whether this sector will benefit from climate issues. Renewable energy could become an important competitor if enough electricity could be produced. A state has been reached in which nuclear energy is both difficult to expand and to phase out. The nuclear energy issues are unlikely to affect the European gas market significantly. 53 refs., 10 refs., 13 tabs.

  3. Challenges of the growing African cement market – environmental issues, regulative framework, and quality infrastructure requirements

    Directory of Open Access Journals (Sweden)

    Schmidt Wolfram

    2018-01-01

    Full Text Available The African cement, concrete and construction business is growing at rapid pace. The cement sales are expected to grow rapidly until 2050. The number of newly built cement plants increases dramatically and in addition more cements are being imported from outside the continent, e.g. from Turkey, Pakistan, Indonesia, and China, driven by overcapacities in the countries of origin. This causes a high number of potentials and challenges at the same time. Newly built cement plants can operate directly at best technological state of the art and thus incorporate more sustainable technologies as well as produce new and more sustainable products such as cements blended with sustainable supplementary cementitious materials such as calcined clays, and industrial or agricultural by products. At the same time the new variety of binding agent as well as the international imports, which are driven by price considerations, make the cement market prone to quality scatter. This puts pressure on the quality control regulations and institutions to ensure safety of construction, healthy application, and environmental safety for the population. The paper presents possible solutions to build up the rapidly increasing African cement production more sustainably than in the rest of the world as well as the related challenges and obstacles that need to be overcome. Based on experiences with a series of pan-African cement testing laboratory proficiency schemes conclusions are made on technical, regulative and political level.

  4. Simulating Spatial Growth Patterns in Developing Countries: an Agent Based Modelling Approach. A Case of Shama in the Western Region of Ghana

    Science.gov (United States)

    Inkoom, J. N.

    2011-12-01

    In Sub-Saharan Africa, rapid urban growth is characterized by prolific expansion of unplanned (informal) structures, and unguided spatial expansion. These unguided expansions by human agents have outstripped the regulatory capacities of Central and Local government. Governmental institutions in finding solutions to the unguided expansion in unplanned use of land have to call for the modelling of what influences the spatial decision and role of human agents in the growth of informal settlement. The objective of the study is to simulate spatial growth pattern of settlements in the Shama district using an agent based model. The study was conducted within a framework of NetLogo. The NetLogo assisted to incorporate and simulate driving forces that affect location decision-making by households and the growth of informal settlement. A survey was conducted to obtain household location decision preferences. The development of unplanned settlement has been a function of land price, proximity to economic centre's, household economic potential, and the location decision-making patterns of households. The exploratory analysis found particularly that majority of spontaneous development took place on areas liable to floods suggesting that some structures fall outside the required building regulations. The application of the proposed model indicates its potential to improve urban planning policies and decision-making processes in emerging cities of developing countries. Also, the result of the simulation suggests potential preferential location for residential development. The research justifies an approach in the area of simulating urban dynamics with agent-based models.

  5. 21 CFR 888.4200 - Cement dispenser.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cement dispenser. 888.4200 Section 888.4200 Food... DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4200 Cement dispenser. (a) Identification. A cement dispenser is a nonpowered syringe-like device intended for use in placing bone cement (§ 888.3027) into...

  6. Crown and bridge cements: clinical applications.

    Science.gov (United States)

    Bunek, Sabiha S; Powers, John M

    2012-12-01

    Cement selection can be confusing because factors such as substrate, the type of restoration, and patient needs must be considered. Some substrates require additional treatment before cementation. This article describes the most commonly used traditional crown and bridge cements (GI and RMGI) used for metal and metal-ceramic restorations, and resin cements used for all-ceramic restorations. Advantages, disadvantages, indications, and contraindications of cements have been reviewed. Recommended uses of cements for metal, ceramic, and laboratory composite restorations have been presented. General guidelines for surface treatment ot silica- and zirconia-based restorations when using resin cements have been discussed.

  7. The characterisation, improvement and modelling aspects of Frost Salt Scaling of Cement-Based Materials with a High Slag Content

    NARCIS (Netherlands)

    Copuroglu, O.

    2006-01-01

    Blast furnace slag cement concrete is used extensively in a number of countries. In comparison with OPC, it is particularly well known for its excellent performance in marine environments. One dis-advantage of slag cement is its vulnerability to scaling under the combined load of freezing-thawing

  8. Cement/slag chemistry studies

    International Nuclear Information System (INIS)

    Glasser, F.P.; Macphee, D.; Atkins, M.; Beckley, N.; Carson, S.O.; Wilding, C.R.; McHugh, G.

    1988-01-01

    The performance of cement-based matrices intended for radwaste immobilization is assessed. The long-term performance of the matrix is characterized by thermodynamic evaluation of experimental data. The results are presented in a general form, amenable to a range of specific formulations. The interaction of specific radwaste components with cements has been studied, using Iodine as an example. It occurs as both I - and IO 3 - species, but these differ sharply in sorption characteristics. The effect of ionizing radiation of the pH and E h of cement matrices is reported. (author)

  9. Cements in Radioactive Waste Disposal

    International Nuclear Information System (INIS)

    Glasser, F.P.

    2013-01-01

    The use of cement and concrete to immobilise radioactive waste is complicated by the wide- ranging nature of inorganic cementing agents available as well as the range of service environments in which cement is used and the different functions expected of cement. For example, Portland cement based concretes are widely used as structural materials for construction of vaults and tunnels. These constructions may experience a long pre-closure performance lifetime during which they are required to protect against collapse and ingress of water: strength and impermeability are key desirable characteristics. On the other hand, cement and concrete may be used to form backfills, ranging in permeability. Permeable formulations allow gas readily to escape, while impermeable barriers retard radionuclide transport and reduce access of ground water to the waste. A key feature of cements is that, while fresh, they pass through a fluid phase and can be formed into any shape desired or used to infiltrate other materials thereby enclosing them into a sealed matrix. Thereafter, setting and hardening is automatic and irreversible. Where concrete is used to form structural elements, it is also natural to use cement in other applications as it minimises potential for materials incompatibility. Thus cement- mainly Portland cement- has been widely used as an encapsulant for storage, transport and as a radiation shield for active wastes. Also, to form and stabilise structures such as vaults and silos. Relative to other potential matrices, cement also has a chemical immobilisation potential, reacting with and binding with many radionuclides. The chemical potential of cements is essentially sacrificial, thus limiting their performance lifetime. However performance may also be required in the civil engineering sense, where strength is important, so many factors, including a geochemical description of service conditions, may require to be assessed in order to predict performance lifetime. The

  10. Sliding wear of cemented carbides

    International Nuclear Information System (INIS)

    Engqvist, H.; Ederyd, S.; Uhrenius, B.; Hogmark, S.

    2001-01-01

    Cemented carbides are known to be very hard and wear resistant and are therefor often used in applications involving surface damage and wear. The wear rate of cemented carbides is often measured in abrasion. In such tests it has been shown that the wear rate is inversely dependent on the material hardness. The sliding wear is even more of a surface phenomenon than a abrasion, making it difficult to predict friction and wear from bulk properties. This paper concentrates on the sliding wear of cemented carbides and elucidates some wear mechanisms. It is especially shown that a fragmenting wear mechanism of WC is very important for the description of wear of cemented carbides. (author)

  11. Alternative Fuels in Cement Production

    DEFF Research Database (Denmark)

    Larsen, Morten Boberg

    The substitution of alternative for fossil fuels in cement production has increased significantly in the last decade. Of these new alternative fuels, solid state fuels presently account for the largest part, and in particular, meat and bone meal, plastics and tyre derived fuels (TDF) accounted...... for the most significant alternative fuel energy contributors in the German cement industry. Solid alternative fuels are typically high in volatile content and they may differ significantly in physical and chemical properties compared to traditional solid fossil fuels. From the process point of view......, considering a modern kiln system for cement production, the use of alternative fuels mainly influences 1) kiln process stability (may accelerate build up of blockages preventing gas and/or solids flow), 2) cement clinker quality, 3) emissions, and 4) decreased production capacity. Kiln process stability...

  12. Rheological measurements on cement grouts

    International Nuclear Information System (INIS)

    Dalton, M.J.

    1986-06-01

    This report describes the techniques which have been developed at Winfrith for assessing the rheological properties of cement grouts. A discussion of the theory of rheology and its application to cement is given and the methodology for calibrating a special paddle measuring system for a commercial viscometer is described. The use of the system for determining flow curves, equilibrium viscosity, viscosity as a function of shearing time and structure changes is also discussed. (author)

  13. Low pH Cements

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David; Benbow, Steven [Quintessa Ltd., Henley-on-Thames (United Kingdom)

    2007-05-15

    The development of low-pH cements for use in geological repositories for radioactive waste stems from concerns over the potential for deleterious effects upon the host rock and other EBS materials (notably bentonite) under the hyperalkaline conditions (pH > 12) of cement pore fluids. Low pH cement (also known as low heat cement) was developed by the cement industry for use where large masses of cement (e.g. dams) could cause problems regarding heat generated during curing. In low pH cements, the amount of cement is reduced by substitution of materials such as fly ash, blast furnace slag, silica fume, and/or non-pozzolanic silica flour. SKB and Posiva have ruled out the use of blast furnace slag and fly-ash and are focusing on silica fume as a blending agent. Currently, no preferred composition has been identified by these agencies. SKB and Posiva have defined a pH limit {<=} 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate (CSH) gel with a Ca/Si ratio {<=} 0.8. Although there are potential implications for the performance of the spent fuel and cladding due to the presence of hyperalkaline fluids from cement, the principal focus for safety assessment lies with the behaviour of bentonite. There are a number of potential constraints on the interaction of hyperalkaline cement pore fluids with bentonite, including mass balance, thermodynamic issues, mass transport, and kinetics, but none of these is likely to be limiting if conventional OPC cements are employed in repository construction. Nevertheless: Low-pH cements may supply approximately 50 % less hydroxyl ions than conventional OPC for a given volume of cement, but mass balance constraints are complicated by the uncertainty concerning the type of secondary minerals produced during cement-bentonite interaction. The change of aqueous

  14. Low pH Cements

    International Nuclear Information System (INIS)

    Savage, David; Benbow, Steven

    2007-05-01

    The development of low-pH cements for use in geological repositories for radioactive waste stems from concerns over the potential for deleterious effects upon the host rock and other EBS materials (notably bentonite) under the hyperalkaline conditions (pH > 12) of cement pore fluids. Low pH cement (also known as low heat cement) was developed by the cement industry for use where large masses of cement (e.g. dams) could cause problems regarding heat generated during curing. In low pH cements, the amount of cement is reduced by substitution of materials such as fly ash, blast furnace slag, silica fume, and/or non-pozzolanic silica flour. SKB and Posiva have ruled out the use of blast furnace slag and fly-ash and are focusing on silica fume as a blending agent. Currently, no preferred composition has been identified by these agencies. SKB and Posiva have defined a pH limit ≤ 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate (CSH) gel with a Ca/Si ratio ≤ 0.8. Although there are potential implications for the performance of the spent fuel and cladding due to the presence of hyperalkaline fluids from cement, the principal focus for safety assessment lies with the behaviour of bentonite. There are a number of potential constraints on the interaction of hyperalkaline cement pore fluids with bentonite, including mass balance, thermodynamic issues, mass transport, and kinetics, but none of these is likely to be limiting if conventional OPC cements are employed in repository construction. Nevertheless: Low-pH cements may supply approximately 50 % less hydroxyl ions than conventional OPC for a given volume of cement, but mass balance constraints are complicated by the uncertainty concerning the type of secondary minerals produced during cement-bentonite interaction. The change of aqueous

  15. International students' experience of a western medical school: a mixed methods study exploring the early years in the context of cultural and social adjustment compared to students from the host country.

    Science.gov (United States)

    McGarvey, A; Brugha, R; Conroy, R M; Clarke, E; Byrne, E

    2015-07-02

    Few studies have addressed the challenges associated with international students as they adapt to studying medicine in a new host country. Higher level institutions have increasing numbers of international students commencing programmes. This paper explores the experiences of a cohort of students in the early years of medical school in Ireland, where a considerable cohort are from an international background. A mixed exploratory sequential study design was carried out with medical students in the preclinical component of a five year undergraduate programme. Data for the qualitative phase was collected through 29 semi-structured interviews using the peer interview method. Thematic analysis from this phase was incorporated to develop an online questionnaire combined with components of the Student Adaptation to College Questionnaire and Student Integration Questionnaire. First year students were anonymously surveyed online. The Mokken Scaling procedure was used to investigate the students' experiences, both positive and negative. Three main themes are identified; social adjustment, social alienation and cultural alienation. The response rate for the survey was 49% (467 Respondents). The Mokken Scaling method identified the following scales (i) Positive experience of student life; (ii) Social alienation, which comprised of negative items about feeling lonely, not fitting in, being homesick and (iii) Cultural alienation, which included the items of being uncomfortable around cultural norms of dress and contact between the sexes. With the threshold set to H = 0.4. Subscales of the positive experiences of student life scale are explored further. Overall student adjustment to a western third level college was good. Students from regions where cultural distance is greatest reported more difficulties in adjusting. Students from these regions also demonstrate very good adaptation. Some students from the host country and more similar cultural backgrounds were also

  16. Polymer-cement interactions towards improved wellbore cement fracture sealants

    Science.gov (United States)

    Beckingham, B. S.; Iloejesi, C.; Minkler, M. J.; Schindler, A. K.; Beckingham, L. E.

    2017-12-01

    Carbon capture, utilization, and storage (CCUS) in deep geologic formations is a promising means of reducing point source emissions of CO2. In these systems, CO2 is captured at the source and then injected to be utilized (eg. in enhanced oil recovery or as a working fluid in enhanced geothermal energy plants) or stored in geologic formations such as depleted oil and gas reservoirs or saline aquifers. While CCUS in subsurface systems could aid in reducing atmospheric CO2 emissions, the potential for CO2 leakage from these systems to overlying formations remains a major limitation and poses a significant risk to the security of injected CO2. Thus, improved materials for both initial wellbore isolation and repairing leakage pathways that develop over time are sought. One approach for the repair of cement fractures in wellbore (and other) systems is the injection of polymer materials into the fracture with a subsequent environmentally dependent (temperature, pressure, pH, etc.) densification or solidification. Here, we aim to investigate novel polymer materials for use to repair leaking wellbores in the context of CCUS. We synthesize and fully characterize a series of novel polymer materials and utilize a suite of analysis techniques to examine polymer-cement interactions at a range of conditions (namely temperature, pressure and pH). Initial findings will be leveraged to design novel polymer materials for further evaluation in polymer-cement composite cores, cement fracture healing, and the aging behavior of healed cements.

  17. Recent developments in the cement industry: a comparative study between Mexico and India

    Directory of Open Access Journals (Sweden)

    Ganesh Babu Kumaran

    2008-10-01

    Full Text Available Since early twentieth century, the use of cement has become a popular and strategic product for economic growth of every country. In India as in Mexico, the first factories began in the earlier twentieth century, India is nowadays the world’s second largest producer and Mexico is the third firm in cement production, despite being the tenth world producer. The eighties have significate for both countries major structural changes in its economy, which have radically altered the structure and functioning of the cement industry and even more during the decade of the nineties. This article discusses the recent performance of the cement industry in both countries, compares the dynamics and causes that gave rise to these changes. It examines changes in the structure of domestic market in both countries and the strategies employed by large companies that operate in both, including a brief analysis of the role of transnational corporations in their development at the stage of globalization and liberalization of markets that characterizes the last two decades. Finally, it explores the great changes that make possible the growth and expansion of the cement industry during the period, based on technological change, the determinants of competitiveness and the role of economic policies in the development of industry in both countries.

  18. Following “the Roots” of Kratom (Mitragyna speciosa): The Evolution of an Enhancer from a Traditional Use to Increase Work and Productivity in Southeast Asia to a Recreational Psychoactive Drug in Western Countries

    Science.gov (United States)

    Cinosi, Eduardo; Martinotti, Giovanni; Simonato, Pierluigi; Singh, Darshan; Demetrovics, Zsolt; Roman-Urrestarazu, Andres; Bersani, Francesco Saverio; Vicknasingam, Balasingam; Piazzon, Giulia; Li, Jih-Heng; Yu, Wen-Jing; Kapitány-Fövény, Máté; Farkas, Judit; Di Giannantonio, Massimo; Corazza, Ornella

    2015-01-01

    The use of substances to enhance human abilities is a constant and cross-cultural feature in the evolution of humanity. Although much has changed over time, the availability on the Internet, often supported by misleading marketing strategies, has made their use even more likely and risky. This paper will explore the case of Mitragyna speciosa Korth. (kratom), a tropical tree used traditionally to combat fatigue and improve work productivity among farm populations in Southeast Asia, which has recently become popular as novel psychoactive substance in Western countries. Specifically, it (i) reviews the state of the art on kratom pharmacology and identification; (ii) provides a comprehensive overview of kratom use cross-culturally; (iii) explores the subjective experiences of users; (iv) identifies potential risks and side-effects related to its consumption. Finally, it concludes that the use of kratom is not negligible, especially for self-medication, and more clinical, pharmacological, and socioanthropological studies as well as a better international collaboration are needed to tackle this marginally explored phenomenon. PMID:26640804

  19. Following "the Roots" of Kratom (Mitragyna speciosa): The Evolution of an Enhancer from a Traditional Use to Increase Work and Productivity in Southeast Asia to a Recreational Psychoactive Drug in Western Countries.

    Science.gov (United States)

    Cinosi, Eduardo; Martinotti, Giovanni; Simonato, Pierluigi; Singh, Darshan; Demetrovics, Zsolt; Roman-Urrestarazu, Andres; Bersani, Francesco Saverio; Vicknasingam, Balasingam; Piazzon, Giulia; Li, Jih-Heng; Yu, Wen-Jing; Kapitány-Fövény, Máté; Farkas, Judit; Di Giannantonio, Massimo; Corazza, Ornella

    2015-01-01

    The use of substances to enhance human abilities is a constant and cross-cultural feature in the evolution of humanity. Although much has changed over time, the availability on the Internet, often supported by misleading marketing strategies, has made their use even more likely and risky. This paper will explore the case of Mitragyna speciosa Korth. (kratom), a tropical tree used traditionally to combat fatigue and improve work productivity among farm populations in Southeast Asia, which has recently become popular as novel psychoactive substance in Western countries. Specifically, it (i) reviews the state of the art on kratom pharmacology and identification; (ii) provides a comprehensive overview of kratom use cross-culturally; (iii) explores the subjective experiences of users; (iv) identifies potential risks and side-effects related to its consumption. Finally, it concludes that the use of kratom is not negligible, especially for self-medication, and more clinical, pharmacological, and socioanthropological studies as well as a better international collaboration are needed to tackle this marginally explored phenomenon.

  20. Following “the Roots” of Kratom (Mitragyna speciosa: The Evolution of an Enhancer from a Traditional Use to Increase Work and Productivity in Southeast Asia to a Recreational Psychoactive Drug in Western Countries

    Directory of Open Access Journals (Sweden)

    Eduardo Cinosi

    2015-01-01

    Full Text Available The use of substances to enhance human abilities is a constant and cross-cultural feature in the evolution of humanity. Although much has changed over time, the availability on the Internet, often supported by misleading marketing strategies, has made their use even more likely and risky. This paper will explore the case of Mitragyna speciosa Korth. (kratom, a tropical tree used traditionally to combat fatigue and improve work productivity among farm populations in Southeast Asia, which has recently become popular as novel psychoactive substance in Western countries. Specifically, it (i reviews the state of the art on kratom pharmacology and identification; (ii provides a comprehensive overview of kratom use cross-culturally; (iii explores the subjective experiences of users; (iv identifies potential risks and side-effects related to its consumption. Finally, it concludes that the use of kratom is not negligible, especially for self-medication, and more clinical, pharmacological, and socioanthropological studies as well as a better international collaboration are needed to tackle this marginally explored phenomenon.

  1. Degradable borate glass polyalkenoate cements.

    Science.gov (United States)

    Shen, L; Coughlan, A; Towler, M; Hall, M

    2014-04-01

    Glass polyalkenoate cements (GPCs) containing aluminum-free borate glasses having the general composition Ag2O-Na2O-CaO-SrO-ZnO-TiO2-B2O3 were evaluated in this work. An initial screening study of sixteen compositions was used to identify regions of glass formation and cement compositions with promising rheological properties. The results of the screening study were used to develop four model borate glass compositions for further study. A second round of rheological experiments was used to identify a preferred GPC formulation for each model glass composition. The model borate glasses containing higher levels of TiO2 (7.5 mol %) tended to have longer working times and shorter setting times. Dissolution behavior of the four model GPC formulations was evaluated by measuring ion release profiles as a function of time. All four GPC formulations showed evidence of incongruent dissolution behavior when considering the relative release profiles of sodium and boron, although the exact dissolution profile of the glass was presumably obscured by the polymeric cement matrix. Compression testing was undertaken to evaluate cement strength over time during immersion in water. The cements containing the borate glass with 7.5 mol % TiO2 had the highest initial compressive strength, ranging between 20 and 30 MPa. No beneficial aging effect was observed-instead, the strength of all four model GPC formulations was found to degrade with time.

  2. Radwaste solidification system (cement)

    International Nuclear Information System (INIS)

    1977-04-01

    The radwaste solidification system described herein is designed to package and solidify radioactive waste material produced at nuclear power plants using cement solidification agents, and is referred to as RSS(C). This integrated system consists of all the equipment necessary to store and transfer solidification agents and additives, collect and transfer process waste in the form of solids, liquids, slurries, and sludges, and continuously mix these materials under controlled conditions prior to letdown into a disposable container. As an integrated system, the RSS(C) also includes the process instrumentation necessary to monitor all process conditions throughout the radwaste packaging cycle and provides the operator with the controls necessary to operate the system in a variety of packaging modes. A single process train which is considered adequate for PWR's is described. A dual process train with crossover capability and two separate filling stations is recommended for most BWR applications. A general description of the solidification process by system configuration and subsystem and detailed equipment descriptions including process equipment data sheets are presented. Equipment listings are also presented. A narrative discussion of the operating procedures for processing a variety of radwaste types normally produced in BWR's and PWR's is presented. A safety analysis is presented, and a detailed discussion of system maintenance requirements and the estimated radiation exposure incident to maintenance is presented. The results of laboratory and prototype testing conducted by Hitman Nuclear and Development Corp. (HNDC) to establish the process parameters required to achieve a satisfactory solidified product are given. A summary of the engineering and quality verification requirements implemented through the HNDC Quality Assurance Program is presented

  3. 76 FR 76760 - Gray Portland Cement and Cement Clinker From Japan

    Science.gov (United States)

    2011-12-08

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-461 (Third Review)] Gray Portland Cement... duty order on gray Portland cement and cement clinker from Japan would be likely to lead to... the Commission are contained in USITC Publication 4281 (December 2011), entitled Gray Portland Cement...

  4. Seating load parameters impact on dental ceramic reinforcement conferred by cementation with resin-cements.

    LENUS (Irish Health Repository)

    Addison, Owen

    2010-09-01

    Cementation of all-ceramic restorations with resin-cements has been demonstrated to reduce the incidence of fracture in service. The aim was to investigate the influence of loading force and loading duration applied during cementation on the reinforcement conferred by a resin-cement on a leucite reinforced glass-ceramic.

  5. Traction test of temporary dental cements

    OpenAIRE

    Román Rodríguez, Juan Luis; Millan Martínez, Diego; Fons Font, Antonio; Agustín Panadero, Rubén; Fernández Estevan, Lucía

    2017-01-01

    Background Classic self-curing temporary cements obstruct the translucence of provisional restorations. New dual-cure esthetic temporary cements need investigation and comparison with classic cements to ensure that they are equally retentive and provide adequate translucence. The objective is to analyze by means of traction testing in a in vitro study the retention of five temporary cements. Material and Methods Ten molars were prepared and ten provisional resin restorations were fabricated u...

  6. Radioactivity concentrations in common brands of cement in Nigeria

    International Nuclear Information System (INIS)

    Farai, I.P.; Ejeh, J.E.

    2006-01-01

    Radioactivity concentrations of 238 U, 232 Th and 40 K in common brands of Portland cement in Nigeria have been measured using a shielded 7.6 cm x 7.6 cm NaI(Tl) detector coupled to a Canberra series 10 plus multichannel analyzer. The cement samples show significant spread in their radioactivity concentrations, even among samples of the same brand. The weighted means of the activity concentrations of 238 U, 232 Th and 40 K in the different brands were 52.4, 4.1 and 91.8 Bq/kg, respectively. The radium equivalent ranged between 29.1 and 128.1 Bq/kg with a weighted mean value of 68.5 Bq/kg. The values are lower than corresponding values in cement samples in most other countries as contained in recent publications. They are also lower than the UNSCEAR recommended maximum of 370 Bq/kg. The safety criteria developed by ITB Poland for radioactivity in building materials, especially for radon build-up in homes were however, exceeded in some of the cement samples. (authors)

  7. Cementation unit for radioactive wastes

    International Nuclear Information System (INIS)

    Dellamano, Jose Claudio; Vicente, Roberto; Lima, Jose Rodrigues de

    2001-01-01

    This communication describes the waste cementation process and facility developed at Instituto de Pesquisas Energeticas e Nucleares - IPEN. The process is based on 200 litres batch operation, in drum mixing, with continuous cement feeding. The equipment is a single recoverable helicoidal mixer and a turning table that allows the drum to rotate during the mixing operation, simulating a planetary mixer. The facility was designed to treat contact handled liquids and wet solid wastes, but can be adapted for shielded equipment and remote operation. (author)

  8. ADVANCED CEMENTS FOR GEOTHERMAL WELLS

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.

    2007-01-01

    Using the conventional well cements consisting of the calcium silicate hydrates (CaO-SiO{sub 2}-H{sub 2}O system) and calcium aluminum silicate hydrates (CaO-Al{sub 2}O{sub 3}-SiO{sub 2}-H{sub 2}O system) for the integrity of geothermal wells, the serious concern confronting the cementing industries was their poor performance in mechanically supporting the metallic well casing pipes and in mitigating the pipe's corrosion in very harsh geothermal reservoirs. These difficulties are particularly acute in two geological regions: One is the deep hot downhole area ({approx} 1700 m depth at temperatures of {approx} 320 C) that contains hyper saline water with high concentrations of CO{sub 2} (> 40,000 ppm) in conjunction with {approx} 100 ppm H{sub 2}S at a mild acid of pH {approx} 5.0; the other is the upper well region between the well's surface and {approx} 1000 m depth at temperatures up to 200 C. The specific environment of the latter region is characterized by highly concentrated H{sub 2}SO{sub 4} (pH < 1.5) brine containing at least 5000 ppm CO{sub 2}. When these conventional cements are emplaced in these harsh environments, their major shortcoming is their susceptibility to reactions with hot CO{sub 2} and H{sub 2}SO4, thereby causing their deterioration brought about by CO{sub 2}-catalyzed carbonation and acid-initiated erosion. Such degradation not only reduced rapidly the strength of cements, lowering the mechanical support of casing pipes, but also increased the extent of permeability of the brine through the cement layer, promoting the rate of the pipe's corrosion. Severely carbonated and acid eroded cements often impaired the integrity of a well in less than one year; in the worst cases, casings have collapsed within three months, leading to the need for costly and time-consuming repairs or redrilling operations. These were the reasons why the geothermal well drilling and cementing industries were concerned about using conventional well

  9. 21 CFR 872.3275 - Dental cement.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental cement. 872.3275 Section 872.3275 Food and... DENTAL DEVICES Prosthetic Devices § 872.3275 Dental cement. (a) Zinc oxide-eugenol—(1) Identification... filling or as a base cement to affix a temporary tooth filling, to affix dental devices such as crowns or...

  10. Multicomponent modelling of Portland cement hydration reactions

    NARCIS (Netherlands)

    Ukrainczyk, N.; Koenders, E.A.B.; Van Breugel, K.

    2012-01-01

    The prospect of cement and concrete technologies depends on more in depth understanding of cement hydration reactions. Hydration reaction models simulate the development of the microstructures that can finally be used to estimate the cement based material properties that influence performance and

  11. Rice Husk Ash Cement – An alternative pozzolana cement for ...

    African Journals Online (AJOL)

    The engineering properties of the cement resulting from a mixture of OPC plus RHA and lime plus RHA were satisfactory with addition of up to 50% RHA. The RHA improved greatly the compressive strength of lime. The cost of producing RHA was considered in pricing the resulting binder and it showed that the use of RHA ...

  12. Experimental Evaluation of Cement Replacement Fillers on the Performance of Slurry Seal

    Science.gov (United States)

    Fakhri, Mansour; Alrezaei, Hossein Ali; Naji Almasi, Soroush

    2016-10-01

    Reducing the level of roads service is a process that starts from the first day of the operation of road and the slope of deterioration curve of road sustainability becomes faster with the passage of time. After building the road, adopting an economic approach in order to maintain the road is very important. Slurry seal as one type of protective asphalts that works by sealing inactive cracks of the road and increasing skid resistance is the most effective types of restoration with environmentally friendly behaviour. Fillers are responsible for adjusting set time in slurry seal. Cement is the most common filler used in slurry seal. Cements having suitable properties as a filler, has a very energy demanding manufacturing process and a notable amount of energy is used for manufacturing cement in the country annually. On the other hand, manufacturing process and application of cement have increased levels of pollutant gases, followed by significant environmental pollution. So in this study other options as a filler such as hydrated lime, stone powder and the slag from iron melting furnace were compared with two common types of cement (Portland and type-v cement) in the mixtures of slurry seal by wet abrasion and cohesion tests. Results indicated that, in both tests, lime and slag fillers had behaviours close to the cement filler.

  13. Western Sufism

    DEFF Research Database (Denmark)

    Sedgwick, Mark

    , of thought both familiar and less familiar: Neoplatonic emanationism, perennialism, pantheism, universalism, and esotericism. Western Sufism, then, is the product not of the new age but of Islam, the ancient world, and centuries of Western religious and intellectual history. Drawing on sources from antiquity...

  14. Mineralogenic characteristics of osteogenic lineage-committed human dental pulp stem cells following their exposure to a discoloration-free calcium aluminosilicate cement.

    Science.gov (United States)

    Niu, Li-Na; Pei, Dan-Dan; Morris, Matthew; Jiao, Kai; Huang, Xue-Qing; Primus, Carolyn M; Susin, Lisiane F; Bergeron, Brian E; Pashley, David H; Tay, Franklin R

    2016-10-01

    An experimental discoloration-free calcium aluminosilicate cement has been developed with the intention of maximizing the beneficial attributes of tricalcium silicate cements and calcium aluminate cements. The present study examined the effects of this experimental cement (Quick-Set2) on the mineralogenic characteristics of osteogenic lineage-committed human dental pulp stem cells (hDPSCs), by comparing the cellular responses with a commercially available tricalcium silicate cement (white mineral trioxide aggregate (ProRoot(®) MTA); WMTA). The osteogenic potential of hDPSCs exposed to the cements was examined using qRT-PCR for osteogenic gene expressions, Western blot for osteogenic-related protein expressions, alkaline phosphatase enzyme activity, Alizarin red S staining, Fourier transform infrared spectroscopy and transmission electron microscopy of extracellular calcium deposits. Results of the six assays indicated that osteogenic differentiation of hDPSCs was significantly enhanced after exposure to the tricalcium silicate cement or the experimental calcium aluminosilicate cement, with the former demonstrating better mineralogenic stimulation capacity. The better osteogenic stimulating effect of the tricalcium silicate cement on hDPSCs may be due to its relatively higher silicate content, or higher OH(-) and Ca(2+) release. Further investigations with the use of in vivo animal models are required to validate the potential augmenting osteogenic effects of the experimental discoloration-free calcium aluminosilicate cement. Published by Elsevier Ltd.

  15. Assessment of natural radioactivity levels and radiation hazards due to cement industry.

    Science.gov (United States)

    El-Taher, A; Makhluf, S; Nossair, A; Abdel Halim, A S

    2010-01-01

    The cement industry is considered as one of the basic industries that plays an important role in the national economy of developing countries. Activity concentrations of (226)Ra, (232)Th and (40)K in Assiut cement and other local cement types from different Egyptian factories has been measured by using gamma-ray spectrometry. From the measured gamma-ray spectra, specific activities were determined. The measured activity concentrations for these natural radionuclides were compared with the reported data for other countries. The average values obtained for (226)Ra, (232)Th and (40)K activity concentration in different types of cement are lower than the corresponding global values reported in UNSCEAR publications. The obtained results show that the averages of radiation hazard parameters for Assiut cement factory are lower than the acceptable level of 370Bqkg(-1) for radium equivalent Ra(eq), 1 for level index Igammar, the external hazard index Hex dose rate. The manufacturing operation reduces the radiation hazard parameters. Cement does not pose a significant radiological hazard when used for construction of buildings.

  16. False set in aireated cements

    Directory of Open Access Journals (Sweden)

    Vázquez, T.

    1986-06-01

    Full Text Available The influence of aireation on the appearance or elimination of the false setting in industrial portland cements is studied by means of infrared spectroscopy.

    Se estudia por medio de la espectroscopia infrarroja la influencia de la aireación sobre la aparición o eliminación del fraguado, en cemento portland industriales.

  17. Polymer reinforcement of cement systems

    International Nuclear Information System (INIS)

    Swamy, R.N.

    1979-01-01

    In the last couple of decades several cement- and concrete-based composites have come into prominence. Of these, cement-polymer composites, like cement-fibre composites, have been recognised as very promising, and considerable research and development on their properties, fabrication methods and application are in progress. Of the three types of concrete materials which incorporate polymers to form composites, polymer impregnated concrete forms a major development in which hardened concrete is impregnated with a liquid monomer which is subsequently polymerized to form a rigid polymer network in the pores of the parent material. In this first part of the extensive review of the polymer reinforcement of cement systems, the process technology of the various monomer impregnation techniques and the properties of the impregnated composite are assessed critically. It is shown that the high durability and superior performance of polymer impregnated concrete can provide an economic and competitive alternative in in situ strengthening, and in other areas where conventional concrete can only at best provide adequate performance. The review includes a section on radiation-induced polymerization. (author)

  18. Electrically conductive Portland cement concrete.

    Science.gov (United States)

    1986-01-01

    There is a need for an effective, simple-to-install secondary anode system for use in the cathodic protection of reinforced concrete bridge decks. In pursuit of such a system, carbon fibers and carbon black were incorporated in portland cement concre...

  19. Sustainability of cement kiln co-processing of wastes in India: a pilot study.

    Science.gov (United States)

    Baidya, Rahul; Ghosh, Sadhan Kumar; Parlikar, Ulhas V

    2017-07-01

    Co-processing in cement kiln achieves effective utilization of the material and energy value present in the wastes, thereby conserving the natural resources by reducing the use of virgin material. In India, a number of multifolded initiatives have been taken that take into account the potential and volume of waste generation. This paper studies the factors which might influence the sustainability of co-processing of waste in cement kilns as a business model, considering the issues and challenges in the supply chain framework in India in view of the four canonical pillars of sustainability. A pilot study on co-processing was carried out in one of the cement plant in India to evaluate the environmental performance, economical performance, operational performance and social performance. The findings will help India and other developing countries to introduce effective supply chain management for co-processing while addressing the issues and challenges during co-processing of different waste streams in the cement kilns.

  20. THE USE OF SISAL FIBRE AS REINFORCEMENT IN CEMENT BASED COMPOSITES

    Directory of Open Access Journals (Sweden)

    Romildo Dias Tolêdo Filho

    1999-08-01

    Full Text Available ABSTRACT The inclusion of fibre reinforcement in concrete, mortar and cement paste can enhance many of the engineering properties of the basic materials, such as fracture toughness, flexural strength and resistance to fatigue, impact, thermal shock and spalling. In recent years, a great deal of interest has been created worldwide on the potential applications of natural fibre reinforced, cement based composites. Investigations have been carried out in many countries on various mechanical properties, physical performance and durability of cement based matrices reinforced with naturally occurring fibres including sisal, coconut, jute, bamboo and wood fibres. These fibres have always been considered promising as reinforcement of cement based matrices because of their availability, low cost and low consumption of energy. In this review, the general properties of the composites are described in relation to fibre content, length, strength and stiffness. A chronological development of sisal fibre reinforced, cement based matrices is reported and experimental data are provided to illustrate the performance of sisal fibre reinforced cement composites. A brief description on the use of these composite materials as building products has been included. The influence of sisal fibres on the development of plastic shrinkage in the pre-hardened state, on tensile, compressive and bending strength in the hardened state of mortar mixes is discussed. Creep and drying shrinkage of the composites and the durability of natural fibres in cement based matrices are of particular interest and are also highlighted. The results show that the composites reinforced with sisal fibres are reliable materials to be used in practice for the production of structural elements to be used in rural and civil construction. This material could be a substitute asbestos-cement composite, which is a serious hazard to human and animal health and is prohibited in industrialized countries. The

  1. The interaction of pH, pore solution composition and solid phase composition of carbonated blast furnace slag cement paste activated with aqueous sodium monofluorophosphate

    NARCIS (Netherlands)

    Kempl, J.; Copuroglu, O.

    2015-01-01

    Blast Furnace Slag (BFS) is a waste product of industrial steel production and a common additive in the cement industry in Northern European countries. However, cementitious materials made from slag-rich cement, particularly CEM III /B, are very susceptible to carbonation. Recent investigations have

  2. Synthesis of Portland cement and calcium sulfoaluminate-belite cement for sustainable development and performance

    Science.gov (United States)

    Chen, Irvin Allen

    Portland cement concrete, the most widely used manufactured material in the world, is made primarily from water, mineral aggregates, and portland cement. The production of portland cement is energy intensive, accounting for 2% of primary energy consumption and 5% of industrial energy consumption globally. Moreover, portland cement manufacturing contributes significantly to greenhouse gases and accounts for 5% of the global CO2 emissions resulting from human activity. The primary objective of this research was to explore methods of reducing the environmental impact of cement production while maintaining or improving current performance standards. Two approaches were taken, (1) incorporation of waste materials in portland cement synthesis, and (2) optimization of an alternative environmental friendly binder, calcium sulfoaluminate-belite cement. These approaches can lead to less energy consumption, less emission of CO2, and more reuse of industrial waste materials for cement manufacturing. In the portland cement part of the research, portland cement clinkers conforming to the compositional specifications in ASTM C 150 for Type I cement were successfully synthesized from reagent-grade chemicals with 0% to 40% fly ash and 0% to 60% slag incorporation (with 10% intervals), 72.5% limestone with 27.5% fly ash, and 65% limestone with 35% slag. The synthesized portland cements had similar early-age hydration behavior to commercial portland cement. However, waste materials significantly affected cement phase formation. The C3S--C2S ratio decreased with increasing amounts of waste materials incorporated. These differences could have implications on proportioning of raw materials for cement production when using waste materials. In the calcium sulfoaluminate-belite cement part of the research, three calcium sulfoaluminate-belite cement clinkers with a range of phase compositions were successfully synthesized from reagent-grade chemicals. The synthesized calcium sulfoaluminate

  3. Primary cemented total hip arthroplasty: 10 years follow-up

    Directory of Open Access Journals (Sweden)

    Nath Rajendra

    2010-01-01

    Full Text Available Background: Primary cemented total hip arthroplasty is a procedure for non-traumatic and traumatic affections of the hip. Long term follow-up is required to assess the longevity of the implant and establish the procedure. Indo-Asian literature on long term result of total hip arthroplasty is sparse. We present a 10-year follow-up of our patients of primary cemented total hip arthroplasty. Materials and Methods: We operated 31 hips in 30 patients with primary cemented total hip arthroplasty. We followed the cases for a minimum period of 10 years with a mean follow-up period of 12.7 years. The mean age of the patients was 60.7 years (range 37-82 yrs male to female ratio was 2:1. The clinical diagnoses included - avascular necrosis of femoral head (n=15, sero positive rheumatoid arthritis (n=5, seronegative spondylo-arthropathy (n=4, neglected femoral neck fractures (n=3, healed tubercular arthritis (n=2 and post traumatic osteoarthritis of hip (n=2. The prostheses used were cemented Charnley′s total hip (n=12 and cemented modular prosthesis (n=19. The results were assessed according to Harris hip score and radiographs taken at yearly intervals. Results: The mean follow-up is 12.7 yrs (range 11-16 yrs Results in all operated patients showed marked improvement in Harris hip score from preoperative mean 29.2 to 79.9 at 10 years or more followup. However, the non-inflammatory group showed more sustained long term improvement as compared to the inflammatory group, as revealed by the Harris hip score. Mean blood loss was 450ml (±3.7 ml, mean transfusion rate was 1.2 units (±.3. The complications were hypotension (n=7, shortening> 1.5 cm (n=9, superficial infection (n=2 and malposition of prosthesis (n=1. Conclusion: The needs of Indian Asian patients, vary from what is discussed in literature. The pain tolerance is greater than western population and financial constraints are high. Thus revision surgery among Indian-Asian patients is less compared

  4. Research of magnesium phosphosilicate cement

    Science.gov (United States)

    Ding, Zhu

    Magnesium phosphosilicate cement (MPSC) is a novel phosphate bonded cement, which consists mainly of magnesia, phosphate and silicate minerals. The traditional magnesium phosphate cements (MPCs) usually composed by ammonium phosphate, and gaseous ammonia will emit during mixing and in service. There is no noxious ammonia released from MPSC, furthermore, it can recycle a large volume of the non-hazardous waste. The goal of this research is to investigate the composition, reaction products, reaction mechanism, microstructure, properties, durability and applications of the MPSC. MPSC sets rapidly and has high early strength. It reacts better with solid industrial waste when compared to Portland cement. Many solid industrial wastes, such as fly ash, steel slag, coal gangue, red coal gangue, red mud, barium-bearing slag, copper slag, silica fume, and ground granulated blast furnace slag, have been used as the main component (40% by weight) in MPSC. The research has found that these aluminosilicate (or ironsilicate, or calciumsilicate) minerals with an amorphous or glass structure can enhance the performance of MPSC. The disorganized internal structure of amorphous materials may make it possess higher reactivity compared to the crystalline phases. Chemical reaction between phosphate and these minerals may form an amorphous gel, which is favorable to the cementing. Borax, boric acid and sodium tripolyphosphate have been used as retardants in the MPSC system. It is found that boric acid has a higher retarding effect on the setting of cement, than borax does. However, sodium polyphosphate accelerates the reaction of MPSC. The hydration of MPSC is exothermic reaction. The heat evolution may prompt hydrates formation, and shorten the setting process. Modern materials characterization techniques, XRD, DSC, TG-DTA FTIR, XPS, MAS-NMR, SEM, TEM, MIP, etc. were used to analyze the phase composition, micro morphology, and microstructure of hardened MPSC. The main hydration product

  5. Predictors of excess cement and tissue response to fixed implant-supported dentures after cementation.

    Science.gov (United States)

    Korsch, Michael; Robra, Bernt-Peter; Walther, Winfried

    2015-01-01

    The cementation of fixed implant-supported restorations involves the risk of excess cement remaining in the peri-implant tissue that may cause a peri-implant tissue response with attachment loss. The aim was to study the peri-implant tissue response after cementation and to detect potential predictors of excess cement. Clinical complications after cementation in several index cases led to a recall of all patients treated with a special methacrylate cement (one hundred five patients with one hundred eighty-eight implants) and systematic reevaluation of 71 patients (68%) with one hundred twenty-six implants (67%). In all cases, suprastructures including abutments were removed, and findings were documented. Implant diameter was significantly associated with the frequency of excess cement. Implant location or system had no significant effect. Excess cement in turn was associated with bleeding on probing, suppuration, and peri-implant attachment loss. In the absence of excess cement 58.8% of implants had no peri-implant attachment loss versus 37.3% when excess cement was present. With increasing retention time of the methacrylate cement, more peri-implant attachment loss was detected. However, the latter association was not significant. Larger diameters are significantly associated with excess cement in peri-implant tissue. Consequences of excess cement may be increased bleeding on probing, suppuration, and possibly peri-implant attachment loss. © 2013 Wiley Periodicals, Inc.

  6. Retention of gold alloy crowns cemented with traditional and resin cements.

    Science.gov (United States)

    Pinzón, Lilliam M; Frey, Gary N; Winkler, Mark M; Tate, William H; Burgess, John O; Powers, John M

    2009-01-01

    The aim of this study was to measure in vitro retention of cast gold crowns cemented with traditional and resin cements. Forty-eight human molars were prepared on a lathe to produce complete crown preparations with a consistent taper and split into six groups, eight crowns in each group. Crowns were cast in a high-gold alloy and then cemented. After 24 hours, the retention force (N) was recorded and mean values were analyzed by one-way analysis of variance and the Fisher post-hoc least significant difference (PLSD) multiple comparisons test (a = .05). Failure sites were examined under 3100 magnification and recorded. Mean values (SD) for each group in increasing order of retention force were: Harvard Cement: 43 N (27), TempoCem: 59 N (16), PermaCem Dual: 130 N (42), RelyX Luting Cement: 279 N (26), Contax and PermaCem Dual: 286 N (38), and TempoCem with Contax and PermaCem Dual: 340 N (14). The Fisher PLSD interval (P = .05) for comparing cements was 29 N. Zinc-phosphate cement and provisional resin cements had the lowest retention forces. Resin cement with a bonding agent and the hybrid-ionomer cement had similar retention forces. Resin cement with a bonding agent applied after use of a provisional resin cement had a significantly higher retention force than the other cements tested.

  7. Retention of provisional crowns cemented with eight temporary cements: comparative study.

    Science.gov (United States)

    Rego, Mariana Ribeiro de Moraes; Santiago, Luiz Carlos

    2004-09-01

    Many temporary cements are commercially available; therefore, it is necessary to indicate them for each clinical requirement with regard to the tensile strength of prosthetic retainers. Thus, the purpose of this study was to compare the retention of provisional crowns cemented with eight temporary cements, over full crown preparations with standardized mechanical principles as height, taper, and length. For that purpose, eighty human first premolars received full crown preparation with standardized height and taper. Provisional crowns were fabricated and luted with eight brands of temporary cements. Twenty four hours after cementation, the restorations were submitted to tensile strength test in a universal testing machine and the data submitted to ANOVA and Bonferroni tests. Mean tensile strength values ranged from 20.1N for Nogenol cement to 67.5N for Hydro C cement. Statistically significant difference (pcrowns cemented with Hydro C cement were more retentive that than those cemented with the other cements, except for Rely X Temp and Temp Bond. The less retentive crowns were those cemented with Nogenol and Freegenol temporary cements.

  8. Evaluation of the Performance of Local Cements with Imported Class

    African Journals Online (AJOL)

    Portland cement is the most commonly used cement in the oil and gas industry and it accounts for about 99% of all primary cementing operations throughout the world. For Portland cement to qualify as oil well cement, the chemical and physical properties must meet the required standards of the American Petroleum Institute ...

  9. Use sulfoferritic cements in construction

    Science.gov (United States)

    Samchenko, Svetlana V.; Zorin, Dmitriy A.

    2018-03-01

    Currently, high-rise construction has received increasing attention around the world. In the big cities under construction is less space and one solution is the high-rise construction. However, high-rise buildings use special requirements, such as strength, thermal insulation, wind load and others. When concrete is exposed to continuous loads by wind or to mechanical loads, it undergoes abrasion. Resistance to this process depends on the characteristics of materials that the concrete and finishing seams are made of. Research on increasing impact and abrasion resistance of calcium sulfoferrite-based cement stone from the perspective of formation of cement stone structure will be instrumental in developing durable materials for application in high-rise construction.

  10. ROTARY SCREW SYSTEMS IN CEMENT

    OpenAIRE

    Taratuta V. D.; Belokur K. A.; Serga G. V.

    2016-01-01

    The article presents results of research of rotary-screw systems in relation to the creation of rotary kilns for the annealing of-cuttings in the preparation of cement clinker. Using the proposed design, in comparison with known designs of similar purpose, it significantly improves performance, reduces size and power consumption through the use of rotary screw systems in the form of screw rotors and drums made hollow with sidewalls assembled from separate strips or plates of different geometr...

  11. Initial acidity of dental cements.

    Science.gov (United States)

    Brune, D; Evje, D M

    1984-04-01

    The acidity in aqueous solutions following release of acid components from glass ionomer, silicate, zinc phosphate and zinc polycarboxylate cements has been registered by pH measurements. One brand of each type was studied. Initial setting was accomplished at two different temperatures; 23 degrees C and in the interval from 23 degrees C to about 60 degrees C. In the latter case external heat was transferred to the samples by infrared radiation for a period of 2 min. The highest acidity was associated with the silicate specimen, while the lowest acidity was recorded for the zinc polycarboxylate specimen. Exposure to infrared radiation resulted in a reduced acidity for all types of cements. The effect of infrared exposure was most pronounced for the silicate specimens, resulting in a reduction of acid release by a factor of about 10 compared to the nontreated samples. The resistance to acid release was found to be improved by a factor of about 5 for the glass ionomer and about 3 for the zinc phosphate cement treated in a similar way. Clinically, it seems possible considerably to reduce the risk of pulpal injuries associated with the insertion of silicate restorations by using a moderate infrared radiation treatment. Furthermore, the susceptibility of glass ionomer cements to a high initial erosion should be reduced by the use of such a technique. After exposure of the glass ionomer and silicate specimens to infrared radiation at the temperature interval applied, the samples had a more glossy, tooth-like appearance compared to the nonexposed samples, improving the aesthetic properties.

  12. Western Samoa.

    Science.gov (United States)

    1985-12-01

    This discussion of Western Samoa, which lies 2575 km northeast of Auckland, New Zealand, focuses on the following: geography; the people; history; government; political conditions; the economy; foreign relations; and relations the US. The population of Western Samoa, as of 1985, totals 163,000 with an annual growth rate of 0.9%. The infant mortality rate is 13/1000; life expectancy is 65 years. The main islands are formed ranges of extinct volcanoes. Volcanic activity last occurred in 1911. More than 2000 years age, waves of Polynesians migrated from Southeast Asia to the Samoan Islands. Samoans are the 2nd largest Polynesian group, after the Maoris of New Zealand, and speak a Polynesian dialect. Samoans have tended to retain their traditional ways despite exposure to European influence for more than 150 years. Most Samoans live within the traditional social system based on an extended family group, headed by a chief. Western Samoans are Christian. Education is free but not compulsory. In 1967, 95% of the children of primary school age attended school. From 1947 to 1961, a series of constitutional advances, assisted by visits from UN missions, brought Western Samoa from dependent status to self-government and finally to independence. The 1960 constitution is based on the British pattern of parliamentary democracy, modified to take Samoan customs into account. The present head of state holds his position for life. Future heads of state will be elected by the Legislative Assembly for 5-year terms. The Parliament consists of the Legislative Assembly and the head of state. The Supreme Court is the superior court of record and has full jurisdiction in civil, criminal, and constitutional matters. The "matai" of chief system still dominates the politics of Western Samoa, although several political parties have been formed and seem to be taking root. The "matai" system is a predominantly conservative force but does provide for change. Western Samoa is predominantly

  13. Natural cement as the precursor of Portland cement: Methodology for its identification

    International Nuclear Information System (INIS)

    Varas, M.J.; Alvarez de Buergo, M.; Fort, R.

    2005-01-01

    When cements appeared in the 19th century, they took the place of traditional binding materials (lime, gypsum, and hydraulic lime) which had been used until that time. Early cements can be divided into two groups, natural and artificial (Portland) cements. Natural cements were introduced first, but their widespread usage was short-lived as they were quickly replaced by artificial cements (Portland), still the most important and predominant today. The main differences between natural and artificial cements arise during the manufacturing process. The final properties of the cements are greatly influenced by differences in the raw materials and burning temperatures employed. The aim of this paper is to assess the efficiency of traditional analytical techniques (petrographic microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR)) used to differentiate natural and artificial cements

  14. Use of Incineration Solid Waste Bottom Ash as Cement Mixture in Cement Production

    Science.gov (United States)

    Jun, N. H.; Abdullah, M. M. A. B.; Jin, T. S.; Kadir, A. A.; Tugui, C. A.; Sandu, A. V.

    2017-06-01

    Incineration solid waste bottom ash was use to examine the suitability as a substitution in cement production. This study enveloped an innovative technology option for designing new equivalent cement that contains incineration solid waste bottom ash. The compressive strength of the samples was determined at 7, 14, 28 and 90 days. The result was compared to control cement with cement mixture containing incineration waste bottom ash where the result proved that bottom ash cement mixture able achieve its equivalent performance compared to control cement which meeting the requirement of the standards according to EN 196-1. The pozzolanic activity index of bottom ash cement mixture reached 0.92 at 28 days and 0.95 at 90 and this values can be concluded as a pozzolanic material with positive pozzolanic activity. Calcium hydroxide in Portland cement decreasing with the increasing replacement of bottom ash where the reaction occur between Ca(OH)2 and active SiO2.

  15. Modelling porewater chemistry in hydrated Portland cement

    International Nuclear Information System (INIS)

    Berner, U.R.

    1987-01-01

    Extensive employment of concrete is foreseen in radioactive waste repositories. A prerequisite for modelling the interactions between concrete and formation waters is characterization of the concrete system. Available experimental data from high pressure squeezing of cement pore-water indicate that, besides the high pH due to alkali hydroxide dissolution, cement composition itself influences the solubility determining solid phases. A model which simulates the hydration of Portland cement assuming complete hydration of the main clinker minerals is presented. The model also includes parameters describing the reactions between the cement and blending agents. Comparison with measured pore-water data generally gives a consistent picture and, as expected, the model gives correct predictions for pure Portland cements. For blended cements, the required additional parameters can, to some extent, be derived from pore-water analysis. 14 references, 1 figure, 4 tables

  16. 76 FR 50252 - Gray Portland Cement and Cement Clinker From Japan; Scheduling of an Expedited Five-Year Review...

    Science.gov (United States)

    2011-08-12

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-461 (Third Review)] Gray Portland Cement... Duty Order on Gray Portland Cement and Cement Clinker From Japan AGENCY: United States International... Act) to determine whether revocation of the antidumping duty order on gray portland cement and cement...

  17. Globalisation and western music historiography

    Directory of Open Access Journals (Sweden)

    Romanou Katy

    2015-01-01

    Full Text Available Globalisation of musicology and music history aims to fuse the divisions created during Western music’s acme, and is referred to as “post-European historical thinking”. Therefore, “post” and “pre” European historical thinking have much in common. One aspect of this process of fragmentation was that music history was separated from theory and that Western Music Histories succeeded General Music Histories (a development described in some detail in the article. Connecting global music history with “post-European” historical thinking is one among numerous indications of Western awareness that European culture has reached some sort of a terminal phase. Concurrently, countries that have been developing by following Western Europe as a prototype, are leading today some past phase of Western development, which, with the ideas of cultural relativism prevailing, are not considered inferior.

  18. The ovens of the industry of the cement and their contribution to the handling of solid residuals and dangerous

    International Nuclear Information System (INIS)

    Riveros Rojas, Marcelo

    1995-01-01

    The substitution of certain row matters in the process of elaboration of the cement, as flying ashes, polluted soils with petroleum, muds of the industry of the petroleum, oxides of the industry of the steel, foundry sand and tires, they can replace until 40% of the necessities of energy of a cement oven contributing to improve the conservation of the environment. This new technology is using with success in United States and some countries of Europe

  19. Incorporation of bitumen and calcium silicate in cement and lime stabilized soil blocks

    Science.gov (United States)

    Kwan, W. H.; Cheah, C. B.; Ramli, M.; Al-Sakkaf, Y. K.

    2017-04-01

    Providing affordable housing is the most critical problem in many of the developing countries. Using earth materials in building construction is one of the feasible methods to address this issue and it can be a way towards sustainable construction as well. However, the published information on the stabilized soil blocks is limited. Therefore, the present study is conducted to examine the characterization of the soils and engineering properties of the stabilized soil blocks. Four types of stabilizer were used in the study, namely; cement, slaked lime, bitumen emulsion and calcium silicate. Cement and slaked lime were added at different percentages in the range of 5% to 15%, with interval of 2.5%. The percentage was determined based on weight of soil. Meanwhile, bitumen emulsion and calcium silicate were incorporated at various percentages together with 10% of cement. Dosage of bitumen emulsion is in the range of 2% to 10% at interval of 2% while calcium silicate was incorporated at 0.50%, 0.75%, 1.00%, 1.25%, 1.50% and 2.00%. Results show that cement is the most viable stabilizer for the soil block among all stabilizers in this study. The bulk density, optimum moisture content and compressive strengths were increased with the increasing cement content. The most suitable cement content was 10% added at moisture content of 12%. Lime, bitumen and calcium contents were recommended at 5.0%, 6.0% and 1.25%, respectively.

  20. Water dynamics in glass ionomer cements

    Science.gov (United States)

    Berg, M. C.; Jacobsen, J.; Momsen, N. C. R.; Benetti, A. R.; Telling, M. T. F.; Seydel, T.; Bordallo, H. N.

    2016-07-01

    Glass ionomer cements (GIC) are an alternative for preventive dentistry. However, these dental cements are complex systems where important motions related to the different states of the hydrogen atoms evolve in a confined porous structure. In this paper, we studied the water dynamics of two different liquids used to prepare either conventional or resin-modified glass ionomer cement. By combining thermal analysis with neutron scattering data we were able to relate the water structure in the liquids to the materials properties.

  1. The influence of ultrasound on removal of prefabricated metal post cemented with different resin cements

    Directory of Open Access Journals (Sweden)

    Atiyeh Feiz

    2013-01-01

    Conclusion: Ultrasonic energy did not decrease the retention of posts cemented with Panavia or Maxcem Elite cements. Furthermore, it seems that there is no significant difference between removal force of self-etch (Panavia and the self-etch self-adhesive (Maxcem Elite resin cements.

  2. Evaluation of cement thixotropy for the cement of oil wells in areas ...

    African Journals Online (AJOL)

    ... economical for cementing job operations in wells with loss zones. The results also show that the effect of LHF is positive, since in addition to his contribution to long term performances, especially the durability of hardened concrete, it improves the thixotropy of cement made of plaster. Keywords: cementing; lost circulation; ...

  3. Properties of paving units incorporating slag cement

    Directory of Open Access Journals (Sweden)

    Hanan A. El Nouhy

    2013-04-01

    Full Text Available The aim of this study is to investigate the effect and possibility of using Portland slag cement in the production of interlocking paving units. Paving units consist of two layers. Four mixes were cast. The first mix was the control mix, in which Portland cement was used in the two layers. In the second mix, Portland slag cement was used in the upper layer, Portland cement was used in the backing layer. In the third mix, Portland cement was placed in the upper layer, while Portland slag cement was used in the backing layer. Finally, in the fourth mix, Portland cement was fully replaced by Portland slag cement in both layers. Tests were carried out in order to investigate the properties of the manufactured specimens at ages 28 and 180 days, respectively. Compressive strength and abrasion resistance were conducted according to the American Society for Testing and Materials (ASTM C 140 and ASTM C418. Water absorption, split tensile strength, abrasion resistance, as well as, skid resistance were performed according to both Egyptian Standard Specifications (ESS 4382 and European Standard (EN 1338. The Egyptian standard is identical with the European standard. The results indicate that it is feasible to use Portland slag cement in the manufacture of paving blocks as the conditions of the conducted tests were satisfied at age180 days except for the minimum splitting tensile strength test.

  4. Integer programming of cement distribution by train

    Science.gov (United States)

    Indarsih

    2018-01-01

    Cement industry in Central Java distributes cement by train to meet daily demand in Yogyakarta and Central Java area. There are five destination stations. For each destination station, there is a warehouse to load cements. Decision maker of cement industry have a plan to redesign the infrastructure and transportation system. The aim is to determine how many locomotives, train wagons, and containers and how to arrange train schedules with subject to the delivery time. For this purposes, we consider an integer programming to minimize the total of operational cost. Further, we will discuss a case study and the solution the problem can be calculated by LINGO software.

  5. Immobilisation of ion exchange resins in cement

    International Nuclear Information System (INIS)

    Howard, C.G.; Jolliffe, C.B.; Lee, D.J.

    1990-09-01

    The removal of activity from spent decontaminating solutions eg LOMI can be achieved using organic ion exchange resins. These resins can be successfully immobilised in cement based matrices. The optimum cement system contained 10% ordinary Portland cement 84% gg blast furnace slag, 6% microsilica with a water cement ratio of 0.5 and a dry resin loading of 36% with respect to total weight. This formulation was successfully scaled up to 200 litres giving a product with acceptable compressive strength, dimensional stability and elastic modulus. Storage of samples under water appears to have no detrimental effects on the product's properties. (author)

  6. Immobilisation of radwaste in cement based matrices

    International Nuclear Information System (INIS)

    Glasser, F.P.; Macphee, D.; Atkins, M.; Pointer, C.; Cowie, J.; Wilding, C.R.; Mattingley, N.J.; Evans, P.A.

    1989-01-01

    The solubilities and influence on cement pH are reported for calcium aluminate and aluminosulphate hydrates. The solubility of Ca(OH) 2 is reported to 700 bars. Polymerization of C-S-H is investigated by NMR. Specific interactions of U 6+ and iodine (I - , IO 3 - ) with cement components are described. The impact of radiation on cements and the influence of higher temperature are documented. The role of dissolved Ca and CO 2 in groundwaters as dissolution media for cements are reported. (author)

  7. Studies on cement matrix materials used at the Radioactive Waste Treatment Plant for radwaste conditioning

    International Nuclear Information System (INIS)

    Dragolici, Felicia; Lungu, Laura; Nicu, Mihaela; Rotarescu, Gheorghe; Turcanu, Corneliu

    2003-01-01

    The research activities performed by Department of Radioactive Waste Management is focused on the treatment of LLAW products obtained by chemical precipitation and on the conditioning of these products by cementation. The individual mechanisms implied in the chemical precipitation processes are directly dependent on the precipitate properties and structure, which in turn are connected with the initial system composition and the precipitation procedure, i.e. reagent concentration, rate and orders of chemical addition, mixing rate and time and ageing conditions. In case of conditioning by cementation, the chemical nature and proportion of the sludges or concentrates affect both the hydrolysis of the initial cement components and the reactions of metastable hydration constituents, as well as the mechanical strength and chemical resistance of the hardened cemented matrix.Generally, the study of the precipitation products and their behaviour during cementation and the long-term disposal is extremely difficult because of the system complexity (phase composition and structure) and the lack of the non-destructive analytical methods. The experience accumulated by the countries who advanced nuclear programmes in military and socio-economic fields and which produced important volumes of radioactive wastes, leads us to study some of mineral additives to be used in the conditioning and disposal technology. Is well known that some mineral additives can diminish the leaching rate of the radionuclides in the disposal environment.The studies have the purpose to obtain the most propitious mixture of cement-bentonite and cement-volcanic tuff, which have the mechanical properties similar to the cement paste used for the conditioning of radioactive waste.Taking into account the characteristics of these mineral binders, namely a very good plasticity and capacity of adsorption, which lead at the decrease of porosity, the mixture is planned to be used in the future, at the Radioactive

  8. A review of binders used in cemented paste tailings for underground and surface disposal practices.

    Science.gov (United States)

    Tariq, Amjad; Yanful, Ernest K

    2013-12-15

    Increased public awareness of environmental issues coupled with increasingly stringent environmental regulations pertaining to the disposal of sulphidic mine waste necessitates the mining industry to adopt more competent and efficient approaches to manage acid rock drainage. Cemented paste tailings (CPT) is an innovative form of amalgamated material currently available to the mining industry in developed countries. It is made usually from mill tailings mingled with a small amount of binder (customarily Portland cement) and water. The high cost associated with production and haulage of ordinary Portland cement and its alleged average performance as a sole binder in the long term (due to vulnerability to internal sulphate attack) have prompted users to appraise less expensive and technically efficient substitutes for mine tailings paste formulations. Generally, these binders include but are not limited to sulphate resistant cements, and/or as a partial replacement for Portland cement by artificial pozzolans, natural pozzolans, calcium sulphate substances and sodium silicates. The approach to designing environmentally efficient CPT is to ensure long-term stability and effective control over environmental contaminants through the use of composite binder systems with enhanced engineering properties to cater for inherit deficiencies in the individual constituents. The alkaline pore solution created by high free calcium rich cement kiln dust (CKD) (byproduct of cement manufacturing) is capable of disintegrating the solid glassy network of artificial pozzolans to produce reactive silicate and aluminate species when attacked by (OH(-)) ions. The augmented pozzolanic reactivity of CKD-slag and CKD-fly ash systems may produce resilient CPT. Since cemented paste comprising mine tailings and binders is a relatively new technology, a review of the binding materials used in such formulations and their performance evaluation in mechanical fill behaviour was considered pertinent in

  9. Mortality study in an asbestos cement factory in Naples, Italy

    Directory of Open Access Journals (Sweden)

    Simona Menegozzo

    2011-01-01

    Full Text Available The objective of this paper is to investigate mortality among 1247 male asbestos-cement workers employed in an asbestos-cement plant located in Naples. The cohort included 1247 men hired between 1950 and 1986. The follow-up began on January 1st 1965. The vital status and causes of death were ascertained up to December 31 2005. Cause-specific mortality rates of the Campania Region population were used as reference. Relative risks were estimated using Standardized Mortality Ratios (SMRs, and the confidence intervals were calculated at a 95% level (95% CI. A significant increase in mortality was observed for respiratory disease (81 deaths; SMR = 187; 95% CI = 149-233, particularly for pneumoconiosis (42 deaths; SMR = 13 313; 95% CI = 9595-17 996 of which 41 deaths for asbestosis (SMR = 43 385; 95% CI = 31 134-58 857, for pleural cancer (24 deaths; SMR = 2617; 95% CI = 1677-3893, for lung cancer (84 deaths; SMR=153; 95% CI = 122-189 and for peritoneal cancer (9 deaths; SMR = 1985; 95% CI = 908-3769. Non-significant increases were also observed for rectum cancer (6 deaths; SMR = 157; 95% CI = 58-342. In conclusion, consistently with other mortality studies on asbestos-cement workers performed in different countries, an increased mortality from asbestosis, lung cancer, pleural and peritoneal mesothelioma was detected in the present cohort.

  10. Natural radionuclide concentrations of cements in Izmir and dose assessments

    International Nuclear Information System (INIS)

    Tanbay, A.; Yener, G.

    1996-01-01

    The growing demand of electric power and the large domestic deposits of lignite coal have made coal-fired plants grow in number in Aegean Region of Turkey. Some of this coals like Yatagan lignites are known to have high uranium concentration (315-405 Bq/kg for coal, 746-1076 Bq/kg for collected fly ash). The stockpiles of fly ash of these power plants are readily available for industrial uses as in the case of cement production. Therefore to assess the doses arising from building materials especially from cement in the cities of Aegean Region a project has been started beginning from Izmir. The traces of radium, potassium and thorium in 45 cement samples which are collected from building constructions in Izmir have been analysed by gamma spectrometry. The mean concentrations of Ra-226, Th-232 and K-40 were determined. The indoor radionuclide doses were calculated using the mean concentrations found in the measurements of this work. The results were compared with those given for other countries. (author)

  11. A study on provisional cements, cementation techniques, and their effects on bonding of porcelain laminate veneers.

    Science.gov (United States)

    Vinod Kumar, G; Soorya Poduval, T; Bipin Reddy; Shesha Reddy, P

    2014-03-01

    Minimal tooth preparation is required for porcelain laminate veneers, but interim restorations are a must to protect their teeth against thermal insult, chemical irritation, and to provide aesthetics. Cement remaining after the removal of the provisional restoration can impair the etching quality of the tooth surface and fit and final bonding of the porcelain laminate veneer. This in vitro study examined the tooth surface for remaining debris of cement after removal of a provisional restoration. Determine the presence of cement debris on prepared tooth surface subsequent to the removal of provisional restoration. Determine the cement with the least residue following the cleansing procedures. Determine the effect of smear layer on the amount of residual luting cement. Eighty-four extracted natural anterior teeth were prepared for porcelain laminate veneers. For half of the teeth, the smear layer was removed before luting provisional restorations. Veneer provisional restorations were fabricated and luted to teeth with six bonding methods: varnish combined with glass ionomer cement (GIC), varnish combined with resin modified GIC, varnish, spot etching combined with dual-cure luting cement, adhesive combined with GIC, adhesive combined with resin modified GIC, and adhesive, spot etching combined with dual-cure luting cement. After removal of provisional restorations 1 week later, the tooth surface was examined for residual luting material with SEM. Traces of cement debris were found on all the prepared teeth surfaces for all six groups which were cemented with different methods. Cement debris was seen on teeth subsequent to the removal of provisional's. Dual-cure cement had the least residue following the cleansing procedures. Presence of smear layer had no statistical significance in comparison with cement residue. With the use of adhesive the cement debris was always found to be more than with the use of varnish. GIC showed maximum residual cement followed by dual-cure.

  12. Rietveld analysis, powder diffraction and cement

    International Nuclear Information System (INIS)

    Peterson, V.

    2002-01-01

    Full text: Phase quantification of cement is essential in its industrial use, however many methods are inaccurate and/or time consuming. Powder diffraction is one of the more accurate techniques used for quantitative phase analysis of cement. There has been an increase in the use of Rietveld refinement and powder diffraction for the analysis and phase quantification of cement and its components in recent years. The complex nature of cement components, existence of solid solutions, polymorphic variation of phases and overlapping phase peaks in diffraction patterns makes phase quantification of cements by powder diffraction difficult. The main phase in cement is alite, a solid solution of tricalcium silicate. Tricalcium silicate has been found to exist in seven modifications in three crystal systems, including triclinic, monoclinic, and rhombohedral structures. Hence, phase quantification of cements using Rietveld methods usually involves the simultaneous modelling of several tricalcium silicate structures to fit the complex alite phase. An industry ordinary Portland cement, industry and standard clinker, and a synthetic tricalcium silicate were characterised using neutron, laboratory x-ray and synchrotron powder diffraction. Diffraction patterns were analysed using full-profile Rietveld refinement. This enabled comparison of x-ray, neutron and synchrotron data for phase quantification of the cement and examination of the tricalcium silicate. Excellent Rietveld fits were achieved, however the results showed that the quantitative phase analysis results differed for some phases in the same clinker sample between various data sources. This presentation will give a short introduction about cement components including polymorphism, followed by the presentation of some problems in phase quantification of cements and the role of Rietveld refinement in solving these problems. Copyright (2002) Australian X-ray Analytical Association Inc

  13. Antibacterial activity of selected glass ionomer cements

    Directory of Open Access Journals (Sweden)

    Elżbieta Łuczaj-Cepowicz

    2014-01-01

    Full Text Available Introduction: The aim of the paper was to determine the antibacterial activity of four glass ionomer cements against bacteria of the genera Streptococcus and Lactobacillus. Material and methods: Four capsulated glass ionomer cements were applied in the study: Fuji Triage (GC, Fuji IX (GC, Ketac Molar (3M Espe and Ketac Silver (3M Espe. Four standard bacterial strains were used to assess the antibacterial activity of the studied cements: Streptococcus mutans, S. sanguis, S. salivarius and Lactobacillus casei. The antibacterial activity was determined by the agar diffusion method. The bacterial suspension was spread with a cotton swab on TSA plates. For each material six wells (7 mm diameter, 5 mm deep were made with a cork borer. Each well was then filled with freshly prepared cements. The results were obtained by measuring the bacterial growth inhibition zone after 1, 2, 3 and 7 days. Results: Fuji Triage cement inhibited the growth of all bacterial strains. Fuji IX cement demonstrated the most potent antibacterial activity against S. sanguis. Ketac Molar showed antibacterial activity against S. sanguis and S. salivarius, whereas Ketac Silver was efficient against S. mutans as well. Neither of the Ketac cements inhibited growth of the standard L. casei strain. Discussion: Antibacterial activity of glass ionomer cements has attracted the interest of scientists in recent years. Most authors, including us, carried out experiments using the agar diffusion method and demonstrated antibacterial activity of glass ionomer cements. Different antibacterial activity of glass ionomer cements, observed in our study and studies of other authors, depended on the evaluated cement, bacterial strain and period of evaluation.

  14. Antibacterial activity of selected glass ionomer cements

    Directory of Open Access Journals (Sweden)

    Elżbieta Łuczaj-Cepowicz

    2014-01-01

    Full Text Available Introduction: The aim of the paper was to determine the antibacterial activity of four glass ionomer cements against bacteria of the genera Streptococcus and Lactobacillus.Material and methods: Four capsulated glass ionomer cements were applied in the study: Fuji Triage (GC, Fuji IX (GC, Ketac Molar (3M Espe and Ketac Silver (3M Espe. Four standard bacterial strains were used to assess the antibacterial activity of the studied cements: Streptococcus mutans, S. sanguis, S. salivarius and Lactobacillus casei. The antibacterial activity was determined by the agar diffusion method. The bacterial suspension was spread with a cotton swab on TSA plates. For each material six wells (7 mm diameter, 5 mm deep were made with a cork borer. Each well was then filled with freshly prepared cements. The results were obtained by measuring the bacterial growth inhibition zone after 1, 2, 3 and 7 days. Results: Fuji Triage cement inhibited the growth of all bacterial strains. Fuji IX cement demonstrated the most potent antibacterial activity against S. sanguis. Ketac Molar showed antibacterial activity against S. sanguis and S. salivarius, whereas Ketac Silver was efficient against S. mutans as well. Neither of the Ketac cements inhibited growth of the standard L. casei strain. Discussion: Antibacterial activity of glass ionomer cements has attracted the interest of scientists in recent years. Most authors, including us, carried out experiments using the agar diffusion method and demonstrated antibacterial activity of glass ionomer cements. Different antibacterial activity of glass ionomer cements, observed in our study and studies of other authors, depended on the evaluated cement, bacterial strain and period of evaluation.

  15. Analysis of Chemical Composition of Portland Cement in Ghana: A Key to Understand the Behavior of Cement

    OpenAIRE

    Bediako, Mark; Amankwah, Eric Opoku

    2015-01-01

    The performance of Portland cement in concrete or mortar formation is very well influenced by chemical compositions among other factors. Many engineers usually have little information on the chemical compositions of cement in making decisions for the choice of commercially available Portland cement in Ghana. This work analyzed five different brands of Portland cement in Ghana, namely, Ghacem ordinary Portland cement (OPC) and Portland limestone cement (PLC), CSIR-BRRI Pozzomix, Dangote OPC, a...

  16. Revision Total Hip Arthroplasty Using the Cement-in-Cement Technique.

    Science.gov (United States)

    Amanatullah, Derek F; Pallante, Graham D; Floccari, Lorena V; Vasileiadis, George I; Trousdale, Robert T

    2017-03-01

    The cement-in-cement technique is useful in the setting of revision total hip arthroplasty (THA), especially to gain acetabular exposure, change a damaged or loose femoral component, or change the version, offset, or length of a fixed femoral component. The goal of this retrospective study was to assess the clinical and radiographic characteristics of revision THA using the cement-in- cement technique. Between 1971 and 2013, a total of 63 revision THAs used an Omnifit (Osteonics, Mahwah, New Jersey) or Exeter (Howmedica, Mahwah, New Jersey) stem and the cement-in-cement technique at the senior author's institution. Aseptic loosening (74%) was the predominant preoperative diagnosis followed by periprosthetic fracture (14%), instability (8%), and implant fracture (6%). Mean clinical follow-up was 5.5±3.8 years. The Harris Hip Score had a statistically significant increase of 18.5 points (Prevision THA using the cement-in-cement technique. There were 13 returns to the operating room, resulting in an overall failure rate of 21%. Eleven (18%) cases required revision THA, but only 1 (2%) revision THA was for aseptic removal of the femoral component. All other femoral implants had no evidence of component migration, cement mantel fracture, or circumferential lucent lines at final follow-up. The patients who underwent cement-in-cement revision THA at the senior author's institution had good restoration of function but a high complication rate. [Orthopedics. 2017; 40(2):e348-e351.]. Copyright 2016, SLACK Incorporated.

  17. Feasibility of producing nano cement in a traditional cement factory in Iraq

    Directory of Open Access Journals (Sweden)

    Sada Abdalkhaliq Hasan Alyasri

    2017-12-01

    Full Text Available This study investigates the economic feasibility of producing nano cement through the establishment of a production line within an existing cement factory. Creating a nano cement production line within the Alkufa Cement factory in Iraq is selected as a case study. Evaluation measures including internal rate of return (IRR, net present value (NPV and breakeven point (BEP are used to evaluate the possible gain that can be achieved from this option. The results demonstrated a positive NPV. The IRR is found to be 26.8% and BEP is reached within 3 years after the establishment of the line. This indicates that producing nano cement in the existing cement factory is economically feasible and can be more advantageous than the ordinary cement.

  18. Cements in radioactive waste management. Characterization requirements of cement products for acceptance and quality assurance purposes

    International Nuclear Information System (INIS)

    Rahman, A.A.; Glasser, F.P.

    1987-01-01

    Cementitious materials are used as immobilizing matrices for low (LLW) and medium-level wastes (MLW) and are also components of the construction materials in the secondary barriers and the repositories. This report has concerned itself with a critical assessment of the quality assurance aspects of the immobilization and disposal of MLW and LLW cemented wastes. This report has collated the existing knowledge of the use and potential of cementitious materials in radioactive waste immobilization and highlighted the physico-chemical parameters. Subject areas include an assessment of immobilization objectives and cement as a durable material, waste stream and matrix characterization, quality assurance concepts, nature of cement-based systems, chemistry and modelling of cement hydration, role and effect of blending agents, radwaste-cement interaction, assessment of durability, degradative and radiolytic processes in cements and the behaviour of cement-based matrices and their near-field interactions with the environment and the repository conditions

  19. Chloride ingress in cement paste and mortar

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben; Coats, Alison M.

    1999-01-01

    In this paper chloride ingress in cement paste and mortar is followed by electron probe microanalysis. The influence of several paste and exposure parameters on chloride ingress are examined (e.g., water-cement ratio, silica fume addition, exposure time, and temperature), The measurements...

  20. TECHNOLOGICAL CHANGES IN THE CEMENT MANUFACTURING INDUSTRY.

    Science.gov (United States)

    WESSON, CARL E.

    THE PURPOSE OF THIS STUDY IS TO PRESENT A PRELIMINARY PICTURE OF OCCUPATIONAL CHANGES BROUGHT ABOUT IN THE MANUFACTURE OF CEMENT AS A RESULT OF INTRODUCING AUTOMATED EQUIPMENT. ONE AUTOMATED AND SEVERAL CONVENTIONAL TYPE CEMENT PLANTS WERE STUDIED. ANALYSIS OF DATA OBTAINED THROUGH RESEARCH AND DATA COLLECTED DURING THE STUDY REVEALED THAT…

  1. Cemented or cementless total knee arthroplasty?

    Directory of Open Access Journals (Sweden)

    Prudhon Jean-Louis

    2017-01-01

    Full Text Available Introduction: Since 1996 we have been using cementless fixation with hydroxyapatite (HA coating. The purpose of this paper is to compare survivorship of a series of 100 cemented Total Knee Arthroplasty (TKA to a similar series of 100 cementless with a follow up of 11–16 years. Material methods: Both TKA are mobile bearing total knee postero-stabilized. They can be used with cement or without cement. Among 1030 New Wave TKATM implanted from 2002 to 2015 we have identified 100 cemented TKAs and 100 cementless TKAs. All these cases were primary replacement. Differences in survival probability were determined using log-rank test. Results: Survival probabilities at 11 years of follow-up were: Cemented group: 90.2% CI95% [81.9–94.8]; Cementless group: 95.4% CI95% [88.1–98.2]. Comparison between both group showed significant difference, p = 0.32. Discussion: The advantages of cementless TKA are bone stock preservation, cement debris protection and the potential to achieve biologic fixation. Cementless implants rely on a porous or roughened surface to facilitate bone formation. HA has been shown to accelerate bone integration and to decrease micro motion of the components and to increase fixation. With a survival probability of 90.2% (cemented version and 95.4% (cementless version, this total knee prosthesis performs as intended in primary total knee arthroplasty. No statistical differences could be found between cemented and cementless implants.

  2. Pre-portland cements and geopolymers

    Czech Academy of Sciences Publication Activity Database

    Hanzlíček, Tomáš; Perná, Ivana; Ertl, Z.; Miller, S.M.

    2012-01-01

    Roč. 9, č. 1 (2012), s. 57-62 ISSN 1214-9705 Institutional research plan: CEZ:AV0Z30460519 Keywords : caementum * cement itious * calcareous cement Subject RIV: JN - Civil Engineering Impact factor: 0.530, year: 2011 http://www.irsm.cas.cz/materialy/acta_content/2012_01/5_Hanzlicek.pdf

  3. Dangote cement : an African success story?

    NARCIS (Netherlands)

    Akinyoade, A.; Uche, C.U.

    2016-01-01

    This paper critiques the rise of Dangote Cement plc to become the dominant player in the Nigerian cement industry. Although the close relationship between the company's founder, Aliko Dangote, and subsequent Nigerian governments has been an important factor in this success story, we argue that it is

  4. CO2 Capture by Cement Raw Meal

    DEFF Research Database (Denmark)

    Pathi, Sharat Kumar; Lin, Weigang; Illerup, Jytte Boll

    2013-01-01

    The cement industry is one of the major sources of CO2 emissions and is likely to contribute to further increases in the near future. The carbonate looping process has the potential to capture CO2 emissions from the cement industry, in which raw meal for cement production could be used...... as the sorbent. Cyclic experiments were carried out in a TGA apparatus using industrial cement raw meal and synthetic raw meal as sorbents, with limestone as the reference. The results show that the CO2 capture capacities of the cement raw meal and the synthetic raw meal are comparable to those of pure limestone....... The CO2 capture capacity of limestone in the raw meal is lower than for pure limestone. The difference in the CO2 capture capacity decreases with an increase in cycle number. The calcination conditions and composition are major factors that influence the CO2 capture capacity of limestone. At 850 °C in N2...

  5. THE GLASS IONOMER CEMENT IN DENTISTRY

    Directory of Open Access Journals (Sweden)

    Ian Matos Vieira

    2006-08-01

    Full Text Available The glass ionomer cement was developed in the past century 70s, after continuous researches about silicate cement. Over the years, glass ionomers have been playing an important role on restorative dentistry. Initially, the material was used for restoration of small cavities, however, its usage has been increased. The main indications at present are: as core buildup restorative, luting cement, liner and base and as a sealant. Recently, glass ionomer cement has been used for ART restorations and in some medicine fields because of the positive biointeraction with bone cells. Although glass ionomer cements exhibit an initial critical solubility and poor aesthetics, great biological properties like fluoride release to oral environment, chemical bonding to tooth tissues and biocompatibility leads this material elective for many purposes. Finally, their inherent antimicrobial properties contributes to the treatment of many situations in dentistry.

  6. Cement analysis using d + D neutrons

    International Nuclear Information System (INIS)

    Womble, Phillip C.; Paschal, Jon; Moore, Ryan

    2005-01-01

    In the cement industry, the primary concern is quality control. The earlier the cement industry can institute quality control upon their product, the more significant their savings in labor, energy and material. We are developing a prototype cement analyzer using pulsed neutrons from a d-D electronic neutron generator with the goal of ensuring quality control of cement in an on-line manner. By utilizing a low intensity d-D neutron source and a specially-designed moderator assembly, we are able to produce one of the safest neutron-based systems in the market. Also, this design includes some exciting new methods of data acquisition which may substantially reduce the final installation costs. In our proof-of-principle measurements, we were able to measure the primary components of cement (Al, Si, Ca and Fe) to limits required for the raw materials, the derived mixes and the clinkers utilizing this neutron generator

  7. CONCRETE BASED ON MODIFIED DISPERSE CEMENT SYSTEM

    Directory of Open Access Journals (Sweden)

    D. V. Rudenko

    2016-08-01

    Full Text Available Purpose. The article considers definition of the bond types occurring in a modified cement concrete matrix, and the evaluation of the quality of these links in a non-uniform material to determine the geometrical and physical relationships between the structure and the cement matrix modifiers. Methodology. To achieve this purpose the studies covered the microstructure of dispersed modified concrete cement matrix, the structure formation mechanism of the modified cement concrete system of natural hardening; as well as identification of the methods of sound concrete strength assessment. Findings. The author proposed a model of the spatial structure of the concrete cement matrix, modified by particulate reinforcement crystal hydrates. The initial object of study is a set of volume elements (cells of the cement matrix and the system of the spatial distribution of reinforcing crystallohydrates in these volume elements. It is found that the most dangerous defects such as cracks in the concrete volume during hardening are formed as a result of internal stresses, mainly in the zone of cement matrix-filler contact or in the area bordering with the largest pores of the concrete. Originality. The result of the study is the defined mechanism of the process of formation of the initial strength and stiffness of the modified cement matrix due to the rapid growth of crystallohydrates in the space among the dispersed reinforcing modifier particles. Since the lack of space prevents from the free growth of crystals, the latter cross-penetrate, forming a dense structure, which contributes to the growth of strength. Practical value. Dispersed modifying cement matrix provides a durable concrete for special purposes with the design performance characteristics. The developed technology of dispersed cement system modification, the defined features of its structure formation mechanism and the use of congruence principle for the complex of technological impacts of physical

  8. Dentin-cement Interfacial Interaction

    Science.gov (United States)

    Atmeh, A.R.; Chong, E.Z.; Richard, G.; Festy, F.; Watson, T.F.

    2012-01-01

    The interfacial properties of a new calcium-silicate-based coronal restorative material (Biodentine™) and a glass-ionomer cement (GIC) with dentin have been studied by confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), micro-Raman spectroscopy, and two-photon auto-fluorescence and second-harmonic-generation (SHG) imaging. Results indicate the formation of tag-like structures alongside an interfacial layer called the “mineral infiltration zone”, where the alkaline caustic effect of the calcium silicate cement’s hydration products degrades the collagenous component of the interfacial dentin. This degradation leads to the formation of a porous structure which facilitates the permeation of high concentrations of Ca2+, OH-, and CO32- ions, leading to increased mineralization in this region. Comparison of the dentin-restorative interfaces shows that there is a dentin-mineral infiltration with the Biodentine, whereas polyacrylic and tartaric acids and their salts characterize the penetration of the GIC. A new type of interfacial interaction, “the mineral infiltration zone”, is suggested for these calcium-silicate-based cements. PMID:22436906

  9. Detecting Poor Cement Bonding and Zonal Isolation Problems Using Magnetic Cement Slurries

    KAUST Repository

    Nair, Sriramya D.

    2017-10-02

    There has been growing interest in the use of magnetorheological fluids to improve displacement efficiency of fluids (drilling fluids, spacer fluids, cement slurries) in the eccentric casing annuli. When magnetic particles are mixed with the cement slurry for improved displacement, they provide an excellent opportunity for sensing the presence and quality of cement in the annulus. This work focuses on using sophisticated 3D computational electromagnetics to simulate the use of a magnetic cement slurry for well cement monitoring. The main goal is to develop a new tool, which is capable of locating magnetic cement slurry that is placed behind a stainless steel casing. An electromagnetic coil was used to generate a magnetic field inside the borehole. It was found that when a current was passed through the electric coils, magnetic field lines passed through the stainless steel casing, the cement annulus and the rock formation. Three sensors were placed inside the cased borehole and the magnetic field strength variations were observed at these locations. Various factors that have a significant influence on zonal isolation were considered. These include, effect of debonding between casing and cement annulus, effect of changing annuli thickness, influence of a fracture in the rock formation, effect of changing magnetic permeability of cement and finally influence of annuli eccentricity. Based on the results shown in the paper along with the next generation of supersensitive magnetic sensors that are being developed, the magnetic approach appears to be a viable alternative for evaluating the quality of the cement annulus to ensure good zonal isolation.

  10. Parameters of Alumina Cement and Portland Cement with Addition of Chalcedonite Meal

    Science.gov (United States)

    Kotwa, Anna

    2017-10-01

    Aluminous cement is a quick binder with special properties. It is used primarily to make non-standard monolithic components exposed to high temperatures, + 1300°C. It is also a component of adhesives and mortars. It has a very short setting time. It is characterized by rapid increase in mechanical strength and resistance to aggressive sulphates. It can be used in reinforced concrete structures. Laying of concrete, construction mortar made of alumina cement can be carried out even at temperatures of -10°C. This article discusses a comparison of the parameters of hardened mortar made of alumina cement GÓRKAL 40 and Portland cement CEM I 42.5R. The mortars contain an addition of chalcedonite meal with pozzolanic properties, with particle size of less than 0.063μm. The meal was added in amounts of 5% and 20% of cement weight. Chalcedonite meal used in the laboratory research is waste material, resulting from chalcedonite aggregate mining. It has the same properties as the rock from which it originates. We have compared the parameters of hardened mortar i.e. compressive strength, water absorption and capillarity. The addition of 20% chalcedonite meal to mortars made from aluminous cement will decrease durability by 6.1% relative to aluminous cement mortar without addition of meal. Considering the results obtained during the absorbency tests, it can be stated that the addition of chalcedonite meal reduces weight gains in mortars made with cement CEM I 42.5 R and alumina cement. Use of alumina cement without addition of meal in mortars causes an increase of mass by 248% compared to Portland cement mortars without additions, in the absorption tests. The addition of chalcedonite meal did not cause increased weight gain in the capillary action tests. For the alumina cement mortars, a lesser weight gains of 24.7% was reported, compared to the Portland cement mortar after 28 days of maturing.

  11. Dehydration kinetics of Portland cement paste at high temperature

    NARCIS (Netherlands)

    Zhang, Q.; Ye, G.

    2012-01-01

    Portland cement paste is a multiphase compound mainly consisting of calcium-silicate-hydrate (CSH) gel, calcium hydroxide (CH) crystal, and unhydrated cement core. When cement paste is exposed to high temperature, the dehydration of cement paste leads to not only the decline in strength, but also

  12. Effect of Cement Grades on some properties of Sandcrete ...

    African Journals Online (AJOL)

    The purpose of this study is to investigate the effects of cement grade on some properties of sandcrete. The cement used for this work was Ordinary Portland cement (Dangote brand) of grade 42.5 and 32.5 meeting the requirement of ASTM C150 type 1 cement. Three types of fine aggregate was also used to produce ...

  13. Tooth surface treatment strategies for adhesive cementation.

    Science.gov (United States)

    Rohr, Nadja; Fischer, Jens

    2017-04-01

    The aim of this study was to evaluate the effect of tooth surface pre-treatment steps on shear bond strength, which is essential for understanding the adhesive cementation process. Shear bond strengths of different cements with various tooth surface treatments (none, etching, priming, or etching and priming) on enamel and dentin of human teeth were measured using the Swiss shear test design. Three adhesives (Permaflo DC, Panavia F 2.0, and Panavia V5) and one self-adhesive cement (Panavia SA plus) were included in this study. The interface of the cement and the tooth surface with the different pre-treatments was analyzed using SEM. pH values of the cements and primers were measured. The highest bond strength values for all cements were achieved with etching and primer on enamel (25.6 ± 5.3 - 32.3 ± 10.4 MPa). On dentin, etching and priming produced the highest bond strength values for all cements (8.6 ± 2.9 - 11.7 ± 3.5 MPa) except for Panavia V5, which achieved significantly higher bond strengths when pre-treated with primer only (15.3 ± 4.1 MPa). Shear bond strength values were correlated with the micro-retentive surface topography of enamel and the tag length on dentin except for Panavia V5, which revealed the highest bond strength with primer application only without etching, resulting in short but sturdy tags. The highest bond strength can be achieved for Panavia F 2.0, Permaflo DC, and Panavia SA plus when the tooth substrate is previously etched and the respective primer is applied. The new cement Panavia V5 displayed low technique-sensitivity and attained significantly higher adhesion of all tested cements to dentin when only primer was applied.

  14. Gamma Spectrometry Analysis of Different Brands of Cement used in Nigeria

    International Nuclear Information System (INIS)

    Olarinoye, I.O.; Baba-Kutigi, A.N.; Sharifat, I.; Kolo, M.T.

    2014-01-01

    The natural radionuclide content of common brands of cement consumed in Nigeria is presented in this work. Samples of 9 brands of grey ordinary Portland cement (OPC) and 5 brands of white cement were collected and analyzed for their radiological content by gamma spectrometry using a 7.6 x 7.6 NaI(TI) detector. The total average content of 226 Ra, 232 Th and 40 k for all the cement brand samples were 38.1, 27.9 and 301.1 Bq/kg respectively and are lower when compared to the world average (50, 50 and 500 Bq/Kg) in building materials. The evaluated radium equivalent activities, external and internal indices were lower than the recommended safe limit and are comparable with result from similar studies concluded in other countries. The evaluation mean gonadal dose of equivalents of two cement brand samples were found to be higher than the world average in soil while others are less than the world average in soil.

  15. Radiation dose estimation and mass attenuation coefficients of cement samples used in Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Damla, N., E-mail: ndamla@ktu.edu.tr [Batman University, Department of Physics, Batman (Turkey); Cevik, U.; Kobya, A.I. [Karadeniz Technical University, Department of Physics, Trabzon (Turkey); Celik, A. [Giresun University, Department of Physics, Giresun (Turkey); Celik, N. [Karadeniz Technical University, Department of Physics, Trabzon (Turkey); Van Grieken, R. [University of Antwerp, Department of Chemistry, Antwerp (Belgium)

    2010-04-15

    Different cement samples commonly used in building construction in Turkey have been analyzed for natural radioactivity using gamma-ray spectrometry. The mean activity concentrations observed in the cement samples were 52, 40 and 324 Bq kg{sup -1} for {sup 226}Ra, {sup 232}Th and {sup 40}K, respectively. The measured activity concentrations for these radionuclides were compared with the reported data of other countries and world average limits. The radiological hazard parameters such as radium equivalent activities (Ra{sub eq}), gamma index (I{sub {gamma}}) and alpha index (I{sub {alpha}}) indices as well as terrestrial absorbed dose and annual effective dose rate were calculated and compared with the international data. The Ra{sub eq} values of cement are lower than the limit of 370 Bq kg{sup -1}, equivalent to a gamma dose of 1.5 mSv y{sup -1}. Moreover, the mass attenuation coefficients were determined experimentally and calculated theoretically using XCOM in some cement samples. Also, chemical compositions analyses of the cement samples were investigated.

  16. Cementation of silver ions on metallic copper

    International Nuclear Information System (INIS)

    Jaskula, M.

    2009-01-01

    The silver cementation on metallic copper was investigated in the presence or absence of oxygen. The influence of sulphuric acid and copper sulphate concentration on the silver cement morphology was studied in details, and results were linked with the previously determined kinetics data of the process. The morpgology of silver depopsit was found to be independent of the prosence of oxygen in the system in as well as the sulphuric acide concentration. Contrary, the concentration of copper sulphate strongly influenced the morphology of silver deposite. Two-stage mechanism of cementation was proposed. (authors).

  17. Synthesis of pure Portland cement phases

    DEFF Research Database (Denmark)

    Wesselsky, Andreas; Jensen, Ole Mejlhede

    2009-01-01

    Pure phases commonly found in Portland cement clinkers are often used to test cement hydration behaviour in simplified experimental conditions. The synthesis of these phases is covered in this paper, starting with a description of phase relations and possible polymorphs of the four main phases...... in Portland cement, i.e. tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium alumino ferrite. Details of the The process of solid state synthesis are is described in general including practical advice on equipment and techniques. Finally In addition, some exemplary mix compositions...

  18. Thermal behavior of asphalt cements

    International Nuclear Information System (INIS)

    Claudy, P.M.; Letoffe, J.M.; Martin, D.; Planche, J.P.

    1998-01-01

    Asphalt cements are highly complex mixtures of hydrocarbon molecules whose thermal behavior is of prime importance for petroleum and road industry. From DSC, the determination of several thermal properties of asphalts is given, e.g. glass-transition temperature and crystallized fraction content.The dissolution of a pure n-paraffin C n H 2n+2 in an asphalt, as seen by DSC, should be a single peak. For 20 g of these glasses change with time and temperature. The formation of the crystallized phases is superposed to the enthalpic relaxation of the glasses, making a kinetic study very difficult. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  19. Characterization and chemical activity of Portland cement and two experimental cements with potential for use in dentistry.

    Science.gov (United States)

    Camilleri, J

    2008-09-01

    To evaluate the chemical activity of Portland cement and two other cement types with similar chemical composition to mineral trioxide aggregate with the aim of developing these cements for further applications in dentistry. The chemical composition of the three cement types namely Portland cement, calcium sulpho-aluminate cement and calcium fluoro-aluminate cement was evaluated by elemental analysis using energy dispersive analysis with X-ray under the scanning electron microscope and by X-ray diffraction analysis (XRD) to determine the phases. The constituents of the hydration reaction by-products were evaluated by XRD analysis of the set cements at 1, 7, 28 and 56 days and by analysis of the leachate by ion chromatography. The pH of both cements and leachate was determined at different time intervals. Cements admixed with micro-silica were also tested to determine the effect of micro-silica on the reaction by-products. All three cement types were composed of tricalcium silicate as the main constituent phase. The hydration reaction of Portland cement produced calcium hydroxide. However, this was not present in the other cements tested at all ages. Admixed micro-silica had little or no effect on the cements with regard to reaction by-products. The pH of all cements tested was alkaline. Both the experimental calcium sulpho-aluminate cement and calcium fluoro-aluminate cement had different hydration reactions to that of Portland cement even though calcium silicate was the major constituent element of both cement types. No calcium hydroxide was produced as a by-product to cement hydration. Micro-silica addition to the cement had no effect on the hydration reaction.

  20. Influence of Cement Particle-Size Distribution on Early Age Autogenous Strains and Stresses in Cement-Based Materials

    DEFF Research Database (Denmark)

    Bentz, Dale P.; Jensen, Ole Mejlhede; Hansen, Kurt Kielsgaard

    2001-01-01

    The influence of cement particle-size distribution on autogenous strains and stresses in cement pastes of identical water-to-cement ratios is examined for cement powders of four different finenesses. Experimental measurements include chemical shrinkage, to quantify degree of hydration; internal r...

  1. Geotechnical characterization of a triassic clay-cement mixes

    OpenAIRE

    Zokaitė, Kamilė

    2016-01-01

    Geotechnical Characterization of a Triassic Clay-Cement Mix. This thesis deals with modification of Triassic clay with cement, using soil-cement mixing method. For tracking of the changes in geotechnical parameters between clay-cement mix and natural Triassic clay, data from earlier researches were used. During the preparation of the clay-cement mix, 40 % of water was added to the dry natural clay. Also there were made three different groups of specimens were they had different amount of ceme...

  2. Nanofunctionalized zirconia and barium sulfate particles as bone cement additives

    Directory of Open Access Journals (Sweden)

    Riaz Gillani

    2009-12-01

    Full Text Available Riaz Gillani1, Batur Ercan1, Alex Qiao3, Thomas J Webster1,21Division of Engineering, 2Department of Orthopaedics, Brown University, Providence, RI, USA; 3G3 Technology Innovations, LLC, Pittsford, NY, USAAbstract: Zirconia (ZrO2 and barium sulfate (BaSO4 particles were introduced into a methyl methacrylate monomer (MMA solution with polymethyl methacrylate (PMMA beads during polymerization to develop the following novel bone cements: bone cements with unfunctionalized ZrO2 micron particles, bone cements with unfunctionalized ZrO2 nanoparticles, bone cements with ZrO2 nanoparticles functionalized with 3-(trimethoxysilylpropyl methacrylate (TMS, bone cements with unfunctionalized BaSO4 micron particles, bone cements with unfunctionalized BaSO4 nanoparticles, and bone cements with BaSO4 nanoparticles functionalized with TMS. Results demonstrated that in vitro osteoblast (bone-forming cell densities were greater on bone cements containing BaSO4 ceramic particles after four hours compared to control unmodified bone cements. Osteoblast densities were also greater on bone cements containing all of the ceramic particles after 24 hours compared to unmodified bone cements, particularly those bone cements containing nanofunctionalized ceramic particles. Bone cements containing ceramic particles demonstrated significantly altered mechanical properties; specifically, under tensile loading, plain bone cements and bone cements containing unfunctionalized ceramic particles exhibited brittle failure modes whereas bone cements containing nanofunctionalized ceramic particles exhibited plastic failure modes. Finally, all bone cements containing ceramic particles possessed greater radio-opacity than unmodified bone cements. In summary, the results of this study demonstrated a positive impact on the properties of traditional bone cements for orthopedic applications with the addition of unfunctionalized and TMS functionalized ceramic nanoparticles

  3. Influence of cementation and cement type on the fracture load testing methodology of anterior crowns made of different materials.

    Science.gov (United States)

    Stawarczyk, Bogna; Beuer, Florian; Ender, Andreas; Roos, Malgorzata; Edelhoff, Daniel; Wimmer, Timea

    2013-01-01

    To evaluate the influence of cementation on fracture load of anterior crowns made of CAD/CAM-resin-blocks (ART), leucite-reinforced glass-ceramics (LRG), lithium disilicate ceramics (LIT), veneered zirconia (ZRO) and veneered alloy (DEG). Each crown group (n=15/subgroup) was cemented on the metal abutment as follows: i. using glass ionomer, ii. using self-adhesive resin cement, and iii. not cemented. Crowns were tested and analyzed with 2-way and 1-way ANOVA (Scheffé test), and Weibull statistics (pcompared to other groups (pcrowns than for cemented (pmetal ceramic crowns should be generally cemented. Glass-ceramic crowns should be cemented using adhesive cement. Cementation and cement type did not have an influence on the fracture load results for resin, zirconia or lithium disilicate crowns.

  4. Shielding properties of fibre cement wallboard.

    Science.gov (United States)

    Thiele, D L; Godwin, G A; Coakley, K S

    1998-09-01

    Transmission data for a fibre cement wallboard (villaboard) are determined for use in diagnostic shielding designs. Villaboard is found to be more attenuating than plasterboard e.g. 9 mm of villaboard is equivalent to 16 mm of plasterboard.

  5. Recycled concrete aggregate in portland cement concrete.

    Science.gov (United States)

    2013-01-01

    Aggregates can be produced by crushing hydraulic cement concrete and are known as recycled concrete : aggregates (RCA). This report provides results from a New Jersey Department of Transportation study to identify : barriers to the use of RCA in new ...

  6. High performance concrete with blended cement

    International Nuclear Information System (INIS)

    Biswas, P.P.; Saraswati, S.; Basu, P.C.

    2012-01-01

    Principal objectives of the proposed project are two folds. Firstly, to develop the HPC mix suitable to NPP structures with blended cement, and secondly to study its durability necessary for desired long-term performance. Three grades of concrete to b considered in the proposed projects are M35, M50 and M60 with two types of blended cements, i.e. Portland slag cement (PSC) and Portland pozzolana cement (PPC). Three types of mineral admixtures - silica fume, fly ash and ground granulated blast furnace slag will be used. Concrete mixes with OPc and without any mineral admixture will be considered as reference case. Durability study of these mixes will be carried out

  7. Recycled materials in Portland cement concrete

    Science.gov (United States)

    2000-06-01

    This report pertains to a comprehensive study involving the use of recycled materials in Portland cement concrete. Three different materials were studied including crushed glass (CG), street sweepings (SS), and recycled concrete (RC). Blast furnace s...

  8. Basalt waste added to Portland cement

    Directory of Open Access Journals (Sweden)

    Thiago Melanda Mendes

    2016-08-01

    Full Text Available Portland cement is widely used as a building material and more than 4.3 billion tons were produced in 2014, with increasing environmental impacts by this industry, mainly through CO2 emissions and consumption of non-removable raw materials. Several by-products have been used as raw materials or fuels to reduce environmental impacts. Basaltic waste collected by filters was employed as a mineral mixture to Portland cement and two fractions were tested. The compression strength of mortars was measured after 7 days and Scanning Electron Microscopy (SEM and Electron Diffraction Scattering (EDS were carried out on Portland cement paste with the basaltic residue. Gains in compression strength were observed for mixtures containing 2.5 wt.% of basaltic residue. Hydration products observed on surface of basaltic particles show the nucleation effect of mineral mixtures. Clinker substitution by mineral mixtures reduces CO2 emission per ton of Portland cement.

  9. Subgrade stabilization alternatives to lime and cement.

    Science.gov (United States)

    2010-04-15

    This project involved four distinct research activities, (1) the influence of temperature on lime-stabilized soils, (2) the influence of temperature on cement-stabilized soils (3) temperature modeling of stabilized subgrade and (4) use of calcium chl...

  10. Cementation of radioactive liquid scintillator waste simulate

    International Nuclear Information System (INIS)

    Bayoumi, T.A.

    2010-01-01

    Liquid scintillation counting is an important analytical tool with extensive applications in medicine and basic applied research and used in quantification of □ -particles, weak □ and x-rays. The generated spent liquid scintillator radioactive waste should be limited and controlled to protect man and his environment. In this study, the radioactive spent liquid scintillator waste simulate (SLS) was immobilized in cement matrix using a surfactant in order to facilitate and increase the amount of SLS incorporated into the cementitious materials. Mechanical properties of the final cement waste form were acceptable for blocks containing up to 20% SLS in presence of surfactant. X-ray diffraction, IR analysis and scanning electron microscope proved that the hydration of cement materials is not significantly affected by organic scintillator waste. Therefore, the cement matrix could be recommended for solidification of SLS for the acceptable mechanical, physical and chemical characterizations reached.

  11. Topics in cement and concrete research

    OpenAIRE

    Brouwers, Jos; Russel, M.I.; Basheer, P.A.M.

    2007-01-01

    The present paper addresses several topics in regard to the sustainable design and use of concrete. First, major features concerning the sustainable aspects of the material concrete are summarised. Then the major constituent, from an environmental point of view, cement is discussed in detail, particularly the hydration and application of slag cement. The intelligent combining of mineral oxides, which are found in clinker, slag, fly ashes etc., is designated as mineral oxide engineering. It re...

  12. Alternative Fuels in Cement Clinker Production Process

    OpenAIRE

    , E Zaka; , R Pinguli; , J Gabili; , E Arapi

    2016-01-01

    Cement industry in Albania is experiencing a rapid development, but this industry is distinguished for high consumption of resources. Cement manufacturing companies do constantly researches on reducing the production cost by optimizing the equipments, replacing raw materials and fuel. However, alternative fuels should be alternative according to the process requirements, easily obtainable in quantity, and with a lower cost. Since the combustible fuels are becoming increasingly important, this...

  13. Tooth surface treatment strategies for adhesive cementation

    OpenAIRE

    Rohr, Nadja; Fischer, Jens

    2017-01-01

    PURPOSE The aim of this study was to evaluate the effect of tooth surface pre-treatment steps on shear bond strength, which is essential for understanding the adhesive cementation process. MATERIALS AND METHODS Shear bond strengths of different cements with various tooth surface treatments (none, etching, priming, or etching and priming) on enamel and dentin of human teeth were measured using the Swiss shear test design. Three adhesives (Permaflo DC, Panavia F 2.0, and Panavia V5) and one sel...

  14. Estimating the chloride transport in cement paste

    OpenAIRE

    Princigallo, A.

    2012-01-01

    A method was developed to measure the diffusion coefficient of chloride ions in cement paste based on an analytical solution to Fick’s 2nd law in a cylindrical coordinate system. This natural method yielded diffusivity results within as little as a month. Testing time was reduced by exploiting the three-dimensional inward flux in the specimen. In an attempt to determine the saturation concentration, dense portland cement pastes were exposed to a concentrated chloride solution. The method prov...

  15. Study on properties and testing methods of thermo-responsive cementing system for well cementing in heavy oil thermal recovery

    Science.gov (United States)

    Li, Lianjiang

    2017-08-01

    In this paper, thermo-responsive cement slurry system were being developed, the properties of conventional cement slurry, compressive strength high temperature of cement sheath, mechanical properties of cement sheath and thermal properties of cement sheath were being tested. Results were being used and simulated by Well-Life Software, Thermo-responsive cement slurry system can meet the requirements of heavy oil thermal recovery production. Mechanical and thermal properties of thermo-responsive cement sheath were being tested. Tensile fracture energy of the thermo-responsive cement sheath is larger than conventional cement. The heat absorption capacity of conventional cement sheath is larger than that of thermo-responsive cement sheath, this means more heat is needed for the unit mass once increasing 1.0 °C, which also indicates that thermo-responsive cement own good heat insulating and preservation effects. The heat conductivity coefficient and thermal expansion coefficient of thermo-responsive cement is less than and conventional cement, this means that thermo-responsive cement have good heat preservation and insulation effects with good thermal expansion stabilities.

  16. Evaluation of the amount of excess cement around the margins of cement-retained dental implant restorations: the effect of the cement application method.

    Science.gov (United States)

    Chee, Winston W L; Duncan, Jesse; Afshar, Manijeh; Moshaverinia, Alireza

    2013-04-01

    Complete removal of excess cement from subgingival margins after cementation of implant-supported restorations has been shown to be unpredictable. Remaining cement has been shown to be associated with periimplant inflammation and bleeding. The purpose of this study was to investigate and compare the amount of excess cement after cementation with 4 different methods of cement application for cement-retained implant-supported restorations. Ten implant replicas/abutments (3i) were embedded in acrylic resin blocks. Forty complete veneer crowns (CVCs) were fabricated by waxing onto the corresponding plastic waxing sleeves. The wax patterns were cast and the crowns were cemented to the implant replicas with either an interim (Temp Bond) or a definitive luting agent (FujiCEM). Four methods of cement application were used for cementation: Group IM-Cement applied on the internal marginal area of the crown only; Group AH-Cement applied on the apical half of the axial walls of the crown; Group AA-Cement applied to all axial walls of the interior surface of the crown, excluding the occlusal surface; and Group PI-Crown filled with cement then seated on a putty index formed to the internal configuration of the restoration (cementation device) (n=10). Cement on the external surfaces was removed before seating the restoration. Cement layers were applied on each crown, after which the crown was seated under constant load (80 N) for 10 minutes. The excess cement from each specimen was collected and measured. One operator performed all the procedures. Results for the groups were compared, with 1 and 2-way ANOVA and the Tukey multiple range test (α=.05). No significant difference in the amount of excess/used cement was observed between the 2 different types of cements (P=.1). Group PI showed the least amount of excess cement in comparison to other test groups (P=.031). No significant difference was found in the amount of excess cement among groups MI, AH, and AA. Group AA showed the

  17. Development of a biodegradable bone cement

    International Nuclear Information System (INIS)

    Yusof Abdullah; Nurhaslinda Ee Abdullah; Wee Pee Chai; Norita Mohd Zain

    2002-01-01

    Biodegradable bone cement is a newly developed bone repair material, which is able to give immediate support to the implant area, and does not obstruct the bone repairing and regeneration process through appropriate biodegradation rate, which is synchronized with the mechanical load it should bear. The purpose of this study is to locally produce biodegradable bone cement using HA as absorbable filler. The cement is composed of an absorbable filler and unsaturated polyester for 100% degradation. Cross-linking effect is achieved through the action of poly (vinyl pyrrol lidone) (PVP) and an initiator. On the other hand, PPF was synthesized using direct esterification method. Characteristics of the bone cement were studied; these included the curing time, cross-linking effect and curing temperature. The products were characterized using X-Ray diffraction (XRD) to perform phase analysis and Scanning Electrons Microscopes to determine the morphology. The physical and mechanical properties of the bone cement were also investigated. The biocompatibility of the bone cement was tested using simulated body physiological solution. (Author)

  18. Case Study of the California Cement Industry

    Energy Technology Data Exchange (ETDEWEB)

    Coito, Fred; Powell, Frank; Worrell, Ernst; Price, Lynn; Friedmann, Rafael

    2005-05-01

    California is the largest cement producing state in theU.S., accounting for between 10 percent and 15 percent of U.S. cementproduction and cement industry employment. The cement industry inCalifornia consists of 31 sites that consume large amounts of energy,annually: 1,600 GWh of electricity, 22 million therms of natural gas, 2.3million tons of coal, 0.25 tons of coke, and smaller amounts of wastematerials, including tires. The case study summarized in this paperfocused on providing background information, an assessment ofenergy-efficiency opportunities and barriers, and program recommendationsthat can be used by program planners to better target products to thecement industry. The primary approach to this case study involvedwalk-through surveys of customer facilities and in depth interviews withcustomer decision makers and subsequent analysis of collected data. Inaddition, a basic review of the cement production process was developed,and summary cement industry energy and economic data were collected, andanalyzed. The analysis of secondary data provides background informationon the cement industry and identification of potential energy-efficiencyopportunities. The interviews provide some understanding of the customerperspective about implementation of energy-efficiencyprojects.

  19. The influence of cement thickness on stem subsidence and cement creep in a collarless polished tapered stem: When are thick cement mantles detrimental?

    Science.gov (United States)

    Takahashi, E; Kaneuji, A; Tsuda, R; Numata, Y; Ichiseki, T; Fukui, K; Kawahara, N

    2017-05-01

    Favourable results for collarless polished tapered stems have been reported, and cement creep due to taper slip may be a contributing factor. However, the ideal cement thickness around polished stems remains unknown. We investigated the influence of cement thickness on stem subsidence and cement creep. We cemented six collarless polished tapered (CPT) stems (two stems each of small, medium and large sizes) into composite femurs that had been reamed with a large CPT rasp to achieve various thicknesses of the cement mantle. Two or three tantalum balls were implanted in the proximal cement in each femur. A cyclic loading test was then performed for each stem. The migration of the balls was measured three-dimensionally, using a micro-computed tomography (CT) scanner, before and after loading. A digital displacement gauge was positioned at the stem shoulder, and stem subsidence was measured continuously by the gauge. Final stem subsidence was measured at the balls at the end of each stem. A strong positive correlation was observed between mean cement thickness and stem subsidence in the CT slices on the balls. In the small stems, the balls moved downward to almost the same extent as the stem. There was a significant negative correlation between cement thickness and the horizontal:downward ratio of ball movement. Collarless polished tapered stems with thicker cement mantles resulted in greater subsidence of both stem and cement. This suggests that excessive thickness of the cement mantle may interfere with effective radial cement creep. Cite this article: E. Takahashi, A. Kaneuji, R. Tsuda, Y. Numata, T. Ichiseki, K. Fukui, N. Kawahara. The influence of cement thickness on stem subsidence and cement creep in a collarless polished tapered stem: When are thick cement mantles detrimental? Bone Joint Res 2017;6:-357. DOI: 10.1302/2046-3758.65.BJR-2017-0028.R1. © 2017 Kaneuji et al.

  20. In vitro tensile strength of luting cements on metallic substrate.

    Science.gov (United States)

    Orsi, Iara A; Varoli, Fernando K; Pieroni, Carlos H P; Ferreira, Marly C C G; Borie, Eduardo

    2014-01-01

    The aim of this study was to determine the tensile strength of crowns cemented on metallic substrate with four different types of luting agents. Twenty human maxillary molars with similar diameters were selected and prepared to receive metallic core castings (Cu-Al). After cementation and preparation the cores were measured and the area of crown's portion was calculated. The teeth were divided into four groups based on the luting agent used to cement the crowns: zinc phosphate cement; glass ionomer cement; resin cement Rely X; and resin cement Panavia F. The teeth with the crowns cemented were subjected to thermocycling and later to the tensile strength test using universal testing machine with a load cell of 200 kgf and a crosshead speed of 0.5 mm/min. The load required to dislodge the crowns was recorded and converted to MPa/mm(2). Data were subjected to Kruskal-Wallis analysis with a significance level of 1%. Panavia F showed significantly higher retention in core casts (3.067 MPa/mm(2)), when compared with the other cements. Rely X showed a mean retention value of 1.877 MPa/mm(2) and the zinc phosphate cement with 1.155 MPa/mm(2). Glass ionomer cement (0.884 MPa/mm(2)) exhibited the lowest tensile strength value. Crowns cemented with Panavia F on cast metallic posts and cores presented higher tensile strength. The glass ionomer cement showed the lowest tensile strength among all the cements studied.

  1. Investigation of Possible Wellbore Cement Failures During Hydraulic Fracturing Operations

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jihoon; Moridis, George

    2014-11-01

    We model and assess the possibility of shear failure, using the Mohr-Coulomb model ? along the vertical well by employing a rigorous coupled flow-geomechanic analysis. To this end, we vary the values of cohesion between the well casing and the surrounding cement to representing different quality levels of the cementing operation (low cohesion corresponds to low-quality cement and/or incomplete cementing). The simulation results show that there is very little fracturing when the cement is of high quality.. Conversely, incomplete cementing and/or weak cement can causes significant shear failure and the evolution of long fractures/cracks along the vertical well. Specifically, low cohesion between the well and cemented areas can cause significant shear failure along the well, but the same cohesion as the cemented zone does not cause shear failure. When the hydraulic fracturing pressure is high, low cohesion of the cement can causes fast propagation of shear failure and of the resulting fracture/crack, but a high-quality cement with no weak zones exhibits limited shear failure that is concentrated near the bottom of the vertical part of the well. Thus, high-quality cement and complete cementing along the vertical well appears to be the strongest protection against shear failure of the wellbore cement and, consequently, against contamination hazards to drinking water aquifers during hydraulic fracturing operations.

  2. Ceramic residue for producing cements, method for the production thereof, and cements containing same

    OpenAIRE

    Sánchez de Rojas, María Isabel; Frías, Moisés; Asensio, Eloy; Medina Martínez, César

    2014-01-01

    [EN] The invention relates to a ceramic residue produced from construction and demolition residues, as a puzzolanic component of cements. The invention also relates to a method for producing said ceramic residues and to another method of producing cements using said residues. This type of residue is collected in recycling plants, where it is managed. This invention facilitates a potential commercial launch.

  3. Characterization of cement minerals, cements and their reaction products at the atomic and nano scale

    DEFF Research Database (Denmark)

    Skibsted, Jørgen; Hall, Christopher

    2008-01-01

    Recent advances and highlights in characterization methods are reviewed for cement minerals, cements and their reaction products. The emphasis is on X-ray and neutron diffraction, and on nuclear magnetic resonance methods, although X-ray absorption and Raman spectroscopies are discussed briefly...

  4. Country Data

    African Journals Online (AJOL)

    Arab Journal of Nephrology and Transplantation. 2013 Jan;6(1):51-4. Country Data. AJNT. Abstract. Introduction: Hypertension (HTN), diabetes mellitus. (DM) and chronic kidney disease (CKD) are important health problems worldwide, and it is possible to reduce their burden through effective HTN screening and treatment ...

  5. Alternative Fuel for Portland Cement Processing

    Energy Technology Data Exchange (ETDEWEB)

    Schindler, Anton K; Duke, Steve R; Burch, Thomas E; Davis, Edward W; Zee, Ralph H; Bransby, David I; Hopkins, Carla; Thompson, Rutherford L; Duan, Jingran; ; Venkatasubramanian, Vignesh; Stephen, Giles

    2012-06-30

    The production of cement involves a combination of numerous raw materials, strictly monitored system processes, and temperatures on the order of 1500 °C. Immense quantities of fuel are required for the production of cement. Traditionally, energy from fossil fuels was solely relied upon for the production of cement. The overarching project objective is to evaluate the use of alternative fuels to lessen the dependence on non-renewable resources to produce portland cement. The key objective of using alternative fuels is to continue to produce high-quality cement while decreasing the use of non-renewable fuels and minimizing the impact on the environment. Burn characteristics and thermodynamic parameters were evaluated with a laboratory burn simulator under conditions that mimic those in the preheater where the fuels are brought into a cement plant. A drop-tube furnace and visualization method were developed that show potential for evaluating time- and space-resolved temperature distributions for fuel solid particles and liquid droplets undergoing combustion in various combustion atmospheres. Downdraft gasification has been explored as a means to extract chemical energy from poultry litter while limiting the throughput of potentially deleterious components with regards to use in firing a cement kiln. Results have shown that the clinkering is temperature independent, at least within the controllable temperature range. Limestone also had only a slight effect on the fusion when used to coat the pellets. However, limestone addition did display some promise in regards to chlorine capture, as ash analyses showed chlorine concentrations of more than four times greater in the limestone infused ash as compared to raw poultry litter. A reliable and convenient sampling procedure was developed to estimate the combustion quality of broiler litter that is the best compromise between convenience and reliability by means of statistical analysis. Multi-day trial burns were conducted

  6. Chromium content in human skin after in vitro application of ordinary cement and ferrous-sulphate-reduced cement

    DEFF Research Database (Denmark)

    Fullerton, A; Gammelgaard, Bente; Avnstorp, C

    1993-01-01

    The amount of chromium found in human skin after in vitro application of cement suspensions on full-thickness human skin in diffusion cells was investigated. Cement suspensions made from ordinary Portland cement or Portland cement with the chromate reduced with added ferrous sulphate were used....... The cement suspensions were either applied on the skin surface under occlusion for 48 h or applied repeatedly every 24 h for 96 h. No statistically significant difference in chromium content of skin layers between skin exposed to ordinary Portland cement, skin exposed to cement with added ferrous sulphate...... and unexposed skin was observed, despite a more permeable skin barrier at the alkaline pH of the cement suspensions, i.e., pH 12.5. Increased chromium levels in epidermis and dermis were seen when ordinary Portland cement was applied as a suspension with added sodium sulphate (20%) on the skin surface for 96 h...

  7. Cement for oil well developed from ordinary cement: characterization physical, chemical and mineralogical

    International Nuclear Information System (INIS)

    Oliveira, D.N.S.; Neves, G. de A.; Chaves, A.C.; Mendonca, A.M.G.D.; Lima, M.S. de; Bezerra, U.T.

    2012-01-01

    This work aims to characterize a new type of cement produced from the mixture of ordinary Portland cement, which can be used as an option in the cementing of oil wells. To enable this work we used the method of lineal programming for the new cement composition, then conducted tests to characterize through particle size analysis by laser diffraction, chemical analysis by EDX, TGA, X-ray diffraction, time grip, resistance to compression. The overall result showed that the new cement had made low-C3A, takes more time to the CPP, thermal stability up to 500 ° C, the kinetics of hydration and low levels of major components consistent with the specifications of ABNT. (author)

  8. Effect of Cement Type on Autogenous Deformation of Cement-Based Materials

    DEFF Research Database (Denmark)

    Pietro, Lura; Ye, Guang; van Breugel, Klaas

    2004-01-01

    In this paper, measurements of non-evaporable water content, chemical shrinkage, autogenous deformation, internal relative humidity (RH), pore solution composition, and early-age elastic modulus are presented and discussed. All experiments were performed on Portland cement and blast-furnace slag...... (BFS) cement pastes. Self-desiccation shrinkage of the BFS cement paste was modeled based on the RH measurements, following the capillary-tension approach. The main findings of this study are: 1) self-desiccation shrinkage can be related to self-desiccation both for Portland and for BFS cement pastes......, taking into account the influence of the dissolved salts in the pore solution, 2) the BFS cement paste studied shows pronounced self-desiccation and self-desiccation shrinkage, mainly caused by its very fine pore structure....

  9. Petroleum Sludge as gypsum replacement in cement plants: Its Impact on Cement Strength

    Science.gov (United States)

    Benlamoudi, Ali; Kadir, Aeslina Abdul; Khodja, Mohamed

    2017-08-01

    Due to high cost of cement manufacturing and the huge amount of resources exhaustion, companies are trying to incorporate alternative raw materials or by-products into cement production so as to produce alternative sustainable cement. Petroleum sludge is a dangerous waste that poses serious imparts on soil and groundwater. Given that this sludge contains a high percentage of anhydrite (CaSO4), which is the main component of gypsum (CaSO4.2H2O), it may play the same gypsum role in strength development. In this research, a total replacement of gypsum (100%) has been substituted by petroleum sludge in cement production and has led to an increase of 28.8% in UCS values after 28 curing days. Nevertheless, the burning of this waste has emitted a considerable amount of carbon monoxide (CO) gas that needs to be carefully considered prior to use petroleum sludge within cement plants.

  10. Immobilization of radioactive waste in cement based matrices

    International Nuclear Information System (INIS)

    Glasser, F.P.; Rahman, A.A.; Macphee, S.; Atkins, M.; Beckley, N.; Carson, S.

    1986-11-01

    Experimental and theoretical studies of hydrated cement systems are described. The behaviour of slag-based cement is described with a view to predicting their long term pH, Esub(n) and mineralogical balance. Modelling studies which enable the prediction at long ages of cement composites are advanced and a base model of the CaO-SiO 2 -H 2 O system presented. The behaviour of U and I in cements is explored. The tolerance of cement systems for a wide range of miscellaneous waste stream components and environmental hazards is described. The redox potential in cements is effectively lowered by irradiation. (author)

  11. Cement replacement by sugar cane bagasse ash: CO2 emissions reduction and potential for carbon credits.

    Science.gov (United States)

    Fairbairn, Eduardo M R; Americano, Branca B; Cordeiro, Guilherme C; Paula, Thiago P; Toledo Filho, Romildo D; Silvoso, Marcos M

    2010-09-01

    This paper presents a study of cement replacement by sugar cane bagasse ash (SCBA) in industrial scale aiming to reduce the CO(2) emissions into the atmosphere. SCBA is a by-product of the sugar/ethanol agro-industry abundantly available in some regions of the world and has cementitious properties indicating that it can be used together with cement. Recent comprehensive research developed at the Federal University of Rio de Janeiro/Brazil has demonstrated that SCBA maintains, or even improves, the mechanical and durability properties of cement-based materials such as mortars and concretes. Brazil is the world's largest sugar cane producer and being a developing country can claim carbon credits. A simulation was carried out to estimate the potential of CO(2) emission reductions and the viability to issue certified emission reduction (CER) credits. The simulation was developed within the framework of the methodology established by the United Nations Framework Convention on Climate Change (UNFCCC) for the Clean Development Mechanism (CDM). The State of São Paulo (Brazil) was chosen for this case study because it concentrates about 60% of the national sugar cane and ash production together with an important concentration of cement factories. Since one of the key variables to estimate the CO(2) emissions is the average distance between sugar cane/ethanol factories and the cement plants, a genetic algorithm was developed to solve this optimization problem. The results indicated that SCBA blended cement reduces CO(2) emissions, which qualifies this product for CDM projects. 2010 Elsevier Ltd. All rights reserved.

  12. Properties of Non-Structural Concrete Made with Mixed Recycled Aggregates and Low Cement Content.

    Science.gov (United States)

    López-Uceda, Antonio; Ayuso, Jesús; López, Martin; Jimenez, José Ramón; Agrela, Francisco; Sierra, María José

    2016-01-26

    In spite of not being legally accepted in most countries, mixed recycled aggregates (MRA) could be a suitable raw material for concrete manufacturing. The aims of this research were as follows: (i) to analyze the effect of the replacement ratio of natural coarse aggregates with MRA, the amount of ceramic particles in MRA, and the amount of cement, on the mechanical and physical properties of a non-structural concrete made with a low cement content; and (ii) to verify if it is possible to achieve a low-strength concrete that replaces a greater amount of natural aggregate with MRA and that has a low cement content. Two series of concrete mixes were manufactured using 180 and 200 kg/m³ of CEM II/A-V 42.5 R type Portland cement. Each series included seven concrete mixes: one with natural aggregates; two MRA with different ceramic particle contents; and one for each coarse aggregate replacement ratio (20%, 40%, and 100%). To study their properties, compressive and splitting tensile strength, modulus of elasticity, density, porosity, water penetration, and sorptivity, tests were performed. The results confirmed that the main factors affecting the properties analyzed in this research are the amount of cement and the replacement ratio; the two MRAs used in this work presented a similar influence on the properties. A non-structural, low-strength concrete (15 MPa) with an MRA replacement ratio of up to 100% for 200 kg/m³ of cement was obtained. This type of concrete could be applied in the construction of ditches, sidewalks, and other similar civil works.

  13. Properties of Non-Structural Concrete Made with Mixed Recycled Aggregates and Low Cement Content

    Science.gov (United States)

    López-Uceda, Antonio; Ayuso, Jesús; López, Martin; Jimenez, José Ramón; Agrela, Francisco; Sierra, María José

    2016-01-01

    In spite of not being legally accepted in most countries, mixed recycled aggregates (MRA) could be a suitable raw material for concrete manufacturing. The aims of this research were as follows: (i) to analyze the effect of the replacement ratio of natural coarse aggregates with MRA, the amount of ceramic particles in MRA, and the amount of cement, on the mechanical and physical properties of a non-structural concrete made with a low cement content; and (ii) to verify if it is possible to achieve a low-strength concrete that replaces a greater amount of natural aggregate with MRA and that has a low cement content. Two series of concrete mixes were manufactured using 180 and 200 kg/m3 of CEM II/A-V 42.5 R type Portland cement. Each series included seven concrete mixes: one with natural aggregates; two MRA with different ceramic particle contents; and one for each coarse aggregate replacement ratio (20%, 40%, and 100%). To study their properties, compressive and splitting tensile strength, modulus of elasticity, density, porosity, water penetration, and sorptivity, tests were performed. The results confirmed that the main factors affecting the properties analyzed in this research are the amount of cement and the replacement ratio; the two MRAs used in this work presented a similar influence on the properties. A non-structural, low-strength concrete (15 MPa) with an MRA replacement ratio of up to 100% for 200 kg/m3 of cement was obtained. This type of concrete could be applied in the construction of ditches, sidewalks, and other similar civil works. PMID:28787874

  14. CEMENT TRANSPORTATION LIMITED-FLEET MODELING AND ASSIGNING TO RATED DEMANDS

    Directory of Open Access Journals (Sweden)

    Narjes MASHHADI BANDANI

    2017-04-01

    Full Text Available Transportation is an inseparable part of the supply chain, with a key role in product distribution. This role is highlighted when ratio of “the cost of transportation” to “the value of goods” such as cement is significant. Iran has recently become one of the main centers of cement production in the world. However, transportation is the most important challenge in cement distribution because of weak structure of the transportation fleet and its independent action. Independence of and lack of commitment on the part of transportation fleets to cement companies as well as lack of timely delivery due to shortage of transportation in some routes and seasons lead to customers` dissatisfaction and even market loss or lack of market development. One of the significant differences between the transportation system in Iran and that in developed countries is lack of complete productivity of the transportation fleet. It means that trucks are driver-based in Iran. This paper introduces a model considering some issues such as driver-based trucks, size of the transportation fleet based on the number of active trucks, and demand priorities in the cement company. Taking the relation between the number of active trucks and the cement company into account, this model assigns weekly demands to the transportation fleet. It also tries to minimize the delay to respond to demands and increases the efficiency of the transportation fleet. Finally, this current condition-based model is compared with two other models including “no constraints on different routes of trucks” as well as single-route model for trucks.

  15. Quality control of cemented waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Slate, L.J.

    1994-12-31

    To insure that cemented radwaste remains immobilized after disposal, certain standards have been set in Europe by the Commission of the European Communities. One such standard is compressive strength. If the compressive strength can be predicted during the early curing stages, time and money can be saved and the quality of the final waste form guaranteed. It was determined that the 7- and 28-day compressive strength from radwaste cementation can be predicted during the mixing and early curing stages by at least three methods. The three that were studied were maturity, rheology, and impedance. Maturity is a temperature-to-time measurement, rheology is a shear stress-to-shear rate measurement, and impedance is the opposition offered to the flow of alternating current. These three methods were employed on five different cemented radwaste concentrations with three different water-to-cement ratios; thus, a total of 15 different mix designs were considered. The results showed that the impedance was the easiest to employ for an on-line process. The results of the impedance method showed a very good relationship between impedance and water-to-cement ratio; therefore, an accurate prediction of compressive strength of cemented radwaste can be drawn from this method. The results of the theology method were very good. The method showed that concrete conforms to the Bingham plastic rheologic model, and the theology method can be used to predict the compressive strength of cemented radwaste, but may be too cumbersome. The results of the maturity method were shown to be limited in accuracy for determining compressive strength.

  16. Concrete and cement composites used for radioactive waste deposition.

    Science.gov (United States)

    Koťátková, Jaroslava; Zatloukal, Jan; Reiterman, Pavel; Kolář, Karel

    2017-11-01

    This review article presents the current state-of-knowledge of the use of cementitious materials for radioactive waste disposal. An overview of radwaste management processes with respect to the classification of the waste type is given. The application of cementitious materials for waste disposal is divided into two main lines: i) as a matrix for direct immobilization of treated waste form; and ii) as an engineered barrier of secondary protection in the form of concrete or grout. In the first part the immobilization mechanisms of the waste by cement hydration products is briefly described and an up-to date knowledge about the performance of different cementitious materials is given, including both traditional cements and alternative binder systems. The advantages, disadvantages as well as gaps in the base of information in relation to individual materials are stated. The following part of the article is aimed at description of multi-barrier systems for intermediate level waste repositories. It provides examples of proposed concepts by countries with advanced waste management programmes. In the paper summary, the good knowledge of the material durability due to its vast experience from civil engineering is highlighted however with the urge for specific approach during design and construction of a repository in terms of stringent safety requirements. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Effect of wet curing duration on durability parameters of hydraulic cement concretes.

    Science.gov (United States)

    2010-01-01

    Hydraulic cement concrete slabs were cast and stored outdoors in Charlottesville, Virginia, to study the impact of wet curing duration on durability parameters. Concrete mixtures were produced using portland cement, portland cement with slag cement, ...

  18. Experimental Study on Artificial Cemented Sand Prepared with Ordinary Portland Cement with Different Contents.

    Science.gov (United States)

    Li, Dongliang; Liu, Xinrong; Liu, Xianshan

    2015-07-02

    Artificial cemented sand test samples were prepared by using ordinary Portland cement (OPC) as the cementing agent. Through uniaxial compression tests and consolidated drained triaxial compression tests, the stress-strain curves of the artificial cemented sand with different cementing agent contents (0.01, 0.03, 0.05 and 0.08) under various confining pressures (0.00 MPa, 0.25 MPa, 0.50 MPa and 1.00 MPa) were obtained. Based on the test results, the effect of the cementing agent content ( C v ) on the physical and mechanical properties of the artificial cemented sand were analyzed and the Mohr-Coulomb strength theory was modified by using C v . The research reveals that when C v is high (e.g., C v = 0.03, 0.05 or 0.08), the stress-strain curves of the samples indicate a strain softening behavior; under the same confining pressure, as C v increases, both the peak strength and residual strength of the samples show a significant increase. When C v is low (e.g., C v = 0.01), the stress-strain curves of the samples indicate strain hardening behavior. From the test data, a function of C v (the cementing agent content) with c ' (the cohesion force of the sample) and Δϕ' (the increment of the angle of shearing resistance) is obtained. Furthermore, through modification of the Mohr-Coulomb strength theory, the effect of cementing agent content on the strength of the cemented sand is demonstrated.

  19. Experimental Study on Artificial Cemented Sand Prepared with Ordinary Portland Cement with Different Contents

    Directory of Open Access Journals (Sweden)

    Dongliang Li

    2015-07-01

    Full Text Available Artificial cemented sand test samples were prepared by using ordinary Portland cement (OPC as the cementing agent. Through uniaxial compression tests and consolidated drained triaxial compression tests, the stress-strain curves of the artificial cemented sand with different cementing agent contents (0.01, 0.03, 0.05 and 0.08 under various confining pressures (0.00 MPa, 0.25 MPa, 0.50 MPa and 1.00 MPa were obtained. Based on the test results, the effect of the cementing agent content (Cv on the physical and mechanical properties of the artificial cemented sand were analyzed and the Mohr-Coulomb strength theory was modified by using Cv. The research reveals that when Cv is high (e.g., Cv = 0.03, 0.05 or 0.08, the stress-strain curves of the samples indicate a strain softening behavior; under the same confining pressure, as Cv increases, both the peak strength and residual strength of the samples show a significant increase. When Cv is low (e.g., Cv = 0.01, the stress-strain curves of the samples indicate strain hardening behavior. From the test data, a function of Cv (the cementing agent content with c′ (the cohesion force of the sample and Δϕ′ (the increment of the angle of shearing resistance is obtained. Furthermore, through modification of the Mohr-Coulomb strength theory, the effect of cementing agent content on the strength of the cemented sand is demonstrated.

  20. Assessment of Natural Radioactivity Levels of Cements and Cement Composites in the Slovak Republic

    Directory of Open Access Journals (Sweden)

    Adriana Eštoková

    2013-12-01

    Full Text Available The radionuclide activities of 226Ra, 232Th and 40K and radiological parameters (radium equivalent activity, gamma and alpha indices, the absorbed gamma dose rate and external and internal hazard indices of cements and cement composites commonly used in the Slovak Republic have been studied in this paper. The cement samples of 8 types of cements from Slovak cement plants and five types of composites made from cement type CEM I were analyzed in the experiment. The radionuclide activities in the cements ranged from 8.58–19.1 Bq·kg−1, 9.78–26.3 Bq·kg−1 and 156.5–489.4 Bq·kg−1 for 226Ra, 232Th and 40K, respectively. The radiological parameters in cement samples were calculated as follows: mean radium equivalent activity Raeq = 67.87 Bq·kg−1, gamma index Iγ = 0.256, alpha index Iα = 0.067, the absorbed gamma dose rate D = 60.76 nGy·h−1, external hazard index Hex = 0.182 and internal hazard index Hin was 0.218. The radionuclide activity in composites ranged from 6.84–10.8 Bq·kg−1 for 226Ra, 13.1–20.5 Bq·kg−1 for 232Th and 250.4–494.4 Bq·kg−1 for 40K. The calculated radiological parameters of cements were lower than calculated radiological parameters of cement composites.

  1. Colorectal cancer and non-malignant respiratory disease in asbestos cement and cement workers

    International Nuclear Information System (INIS)

    Jacobsson, K.

    1993-09-01

    Radiologically visible parenchymal changes (small opacities >= 1/0;ILO 1980 classification) were present in 20% of a sample of workers (N=174), employed for 20 years (median) in an asbestos cement plant. Exposure-response relationships were found, after controlling for age and smoking habits. In a sample of asbestos cement workers with symptoms and signs suggestive of pulmonary disease (N=33), increased lung density measured by x-ray computed tomography, and reduced static lung volumes and lung compliance was found. In a cohort of asbestos cement workers (N=1.929) with an estimated median exposure of 1.2 fibres/ml, the mortality from non-malignant respiratory disease was increased in comparison to a regional reference cohort (N=1.233). A two-to three-fold increase of non-malignant respiratory mortality was noted among workers employed for more than a decade in the asbestos cement plant, compared to cement workers (N=1.526), who in their turn did not experience and increased risk compared to the general population. In the cohorts of asbestos cement and cement workers, there was a tow-to three-fold increased incidence of cancer in the right part of the colon, compared to the general population as well as to external reference cohorts of other industrial workers (N=3.965) and fishermen (N=8.092). A causal relation with the exposure to mineral dust and fibres was supported by the findings of higher risk estimated in subgroups with high cumulated asbestos doses or longer duration of cement work. The incidence of cancer in the left part of the colon was not increased. Morbidity data, but not mortality data, disclosed the subsite-specific risk pattern. Both asbestos cement workers and cement workers has an increased incidence of rectal cancer, compared with the general population, and with the fishermen. The risk was, however, of the same magnitude among the other industrial workers. 181 refs

  2. Tanzania. A developing mining country; Tansania. Bergbauland im Aufbruch

    Energy Technology Data Exchange (ETDEWEB)

    Elsner, Harald [Bundesanstalt fuer Geowissenschaften und Rohstoffe (BGR), Hannover (Germany). Fachbereich Wirtschaftsgeologie der mineralischen Rohstoffe

    2009-03-19

    Tanzania is the rising country in East Africa, to which not least of all the booming mining sector contributes. Many large gold mines, two precious stone mines, three cement works and smaller facilities for extraction of salt, phosphates, gypsum, pozzolana, coal and coloured gemstones currently characterise the mining sector. The high mineral potential of the country combined with the mining legislation favouring investment will also lead in future to the development of further deposits in particular, nickel, gold, coal and graphite. (orig.)

  3. Manganese Countries

    Directory of Open Access Journals (Sweden)

    Maria Sousa Galito

    2014-05-01

    Full Text Available Cheickna Bounajim Cissé wrote an article in Mars 2013 in the Journal Les Afriques N. º 237, suggesting a new acronym, MANGANESE, for the nine African countries: Morocco, Angola, Namibia, Ghana, Algeria, Nigeria, Egypt, South Africa and Ethiopia. According to Cissé, this group of African nations will be the fastest growing states in the region over the next few years. The purpose of this article is to test the pertinence of the acronym, discuss the credibility and reliability of the future prospects of these countries by comparing selected socioeconomic and sociopolitical indicators based on the latest global rankings and trends. Likewise, the potential of Cissé's claim will be assessed, especially in relationship to drug trafficking and terrorism that may put their recent sustainability in danger now and in the future.

  4. Investigation of Expanding Cements. Report 1. Summary of Information Available as of 1 July 1963

    Science.gov (United States)

    1965-09-01

    research) be tamed and utiliz -a. Today, expectations of such kind may with some right be stamped as banalities, and one might prefer the more limited...the following tabulation: Cementing Material,% by weight Grout Portland Expansive Aluminium Mi_z Type of Grout Cement Fly Ash Component Powder A 8o 20...tures, as a function of the behaviour of cements. Cold cements-- workable cements--ductile cements--non-shrinking cements and cements with controlled

  5. Alpha radioactivity in Indian cement samples

    International Nuclear Information System (INIS)

    Nain, M.; Chauhan, R. P.; Chakarvarti, S. K.

    2006-01-01

    The essential constituents of radioactive and each of cements like lime, silica and alumina are derived from earth's crust in which radioactive elements like uranium, thorium etc are also present in varying amounts almost everywhere. These two elements are considered as the parent elements of uranium and thorium radioactive decay series in which radon and thoron are produced respectively as decay products. In the present study the samples of ordinary Portland cement , Portland pozzolana cement and some other cementious finishing materials like white cement, Plaster of Paris , cement putty etc were collected and analysed for radium and radon concentrations along with radon exhalation rates. Materials and Methods: Alpha sensitive LR-115 Type II plastic track detectors commonly known as S olid State Nuclear Track Detectors w ere used to measure the radium and radon concentration. The alpha particles emitted from the radon causes the radiation damaged tracks. The Chemical etching in NaOH at 60 C for about 90 minutes was done to reveal these latent tracks, which were then scanned and counted by an optical microscope of suitable magnification. By calculating the track density of registered tracks, the radon and radium concentrations along with exhalation rate of radon, were determined using required formulae. Results: The radon and radium concentration in various brands of cements found to vary from 333±9.9 to 506±13.3 Bq m-3 and from 3.7±0.1 to 5.6±0.2 Bq k g-1 while in various cementious finishing materials used in the construction, these were found to vary from 378±19.7 to 550±9.8 Bq m-3 and from 4.2±0.2 to 6.1±0.1 Bq Kg-1, respectively. Based on the data the mass and surface exhalation rates were also calculated Conclusion: The measurements indicate that there is marginal variation of the concentration of radium and radon in various brands of cements in India with lower levels in the cement samples having red oxide and higher levels in fly ash based cement

  6. The influence of temporary cements on dental adhesive systems for luting cementation.

    Science.gov (United States)

    Ribeiro, José C V; Coelho, Paulo G; Janal, Malvin N; Silva, Nelson R F A; Monteiro, André J; Fernandes, Carlos A O

    2011-03-01

    This study tested the hypothesis that bond strength of total- and self-etching adhesive systems to dentine is not affected by the presence of remnants from either eugenol-containing (EC) or eugenol-free (EF) temporary cements after standardized cleaning procedures. Thirty non-carious human third molars were polished flat to expose dentine surfaces. Provisional acrylic plates were fabricated and cemented either with EC, EF or no temporary cements. All specimens were incubated for 7 days in water at 37°C. The restorations were then taken out and the remnants of temporary cements were mechanically removed with a dental instrument. The dentine surfaces were cleaned with pumice and treated with either total-etching (TE) or self-etching (SE) dental adhesive systems. Atomic force microscopy was used to examine the presence of remnants of temporary cements before and after dentine cleaning procedures. Composite resin build-ups were fabricated and cemented to the bonded dentine surfaces with a resin luting cement. The specimens were then sectioned to obtain 0.9mm(2) beams for microtensile bond strength testing. Fractographic analysis was performed by optical and scanning electron microscopy. ANOVA showed lower mean microtensile bond strength in groups of specimens treated with EC temporary cement than in groups treated with either no cement or an EF cement (p<0.05). Mean microtensile bond strength was lower in groups employing the SE rather than the TE adhesive system (p<0.001). SE samples were also more likely to fail during initial processing of the samples. There was no evidence of interaction between cement and adhesive system effects on tensile strength. Fractographic analysis indicated different primary failure modes for SE and TE bonding systems, at the dentine-adhesive interface and at the resin cement-resin composite interface, respectively. The use of eugenol-containing temporary cements prior to indirect bonding restorations reduce, to a statistically similar

  7. Hybrid Alkaline Cements: Bentonite-Opc Binders

    Directory of Open Access Journals (Sweden)

    Ines Garcia-Lodeiro

    2018-03-01

    Full Text Available Moderately alkaline activators can be used to formulate cementitious binders with a high Supplemetary Cementitious Materials (SCMs and a low portland cement content (hybrid alkaline cements. This study aimed to prepare hybrid alkaline cements containing large percentages of dehydroxylated bentonite (BT and small Portland cement (OPC fractions, with 5% Na2SO4 as a solid alkaline activator. The hydration kinetics of the pastes hydrated in water in the presence and absence of the solid activator were assessed by isothermal conduction calorimetry, whilst the reaction products were characterised with X-Ray Powder Diffraction (XRD and Fourier-transform Infrared Spectroscopy (FTIR. The presence of the alkaline activator hastened OPC and BT/OPC hydration: more heat of hydration was released, favouring greater initial bentonite reactivity. The portlandite forming during cement hydration reacted readily with the Na2SO4, raising medium alkalinity and enhancing bentonite dissolution and with it reaction product precipitation (primarily (N,C-A-S-H-like gels that co-exist with C-S-H- or C-A-S-H-like gels. The presence of sulfate ions favoured the formation of AFm-like phases. Preceding aspects accelerated the hydration reactions, with the formation of more reaction product and matrix densification. As a result, the 28 days Na2SO4 activated systems developed greater mechanical strength than the water-hydrated systems, with the 60% BT/40% OPC blends exhibiting higher compressive strength than the 100% OPC pastes.

  8. Accelerated hydration of high silica cements

    International Nuclear Information System (INIS)

    Walker, Colin; Yui, Mikazu

    2012-01-01

    Current Japanese designs for high level radioactive waste (HLW) repositories anticipate the use of both bentonite (buffer and backfill material) and cement based materials. Using hydrated Ordinary Portland Cement (OPC) as a grouting material is undesirable because the associated high pH buffer will have an undisputed detrimental effect on the performance of the bentonite buffer and backfill and of the host rock by changing its porosity. Instead, hydrated low pH cement (LopHC) grouting materials are being developed to provide a pH inferior or equal to 11 to reduce these detrimental effects. LopHC grouting materials use mixtures of superfine OPC (SOPC) clinker and silica fume (SF), and are referred as high silica cements (HSC). The focus of the present study was to identify the development of the unhydrated and hydrated mineral assemblage and the solution chemistry during the hydration of HSC. Since hydration experiments of cementitious materials are notably slow, a ball mill was used to accelerate hydration. This was done for two reasons. Firstly, to develop a method to rapidly hydrate cement based materials without the need for higher temperatures (which can alter the mineral assemblage), and secondly, to ensure that the end point of hydration was reached in a reasonable time frame and so to realize the final mineralogy and solution chemistry of hydrated HSC

  9. Microbial-influenced cement degradation: Literature review

    International Nuclear Information System (INIS)

    Rogers, R.D.; Hamilton, M.A.; McConnell, J.W. Jr.

    1993-03-01

    The Nuclear Regulatory Commission stipulates that disposed low-level radioactive waste (LLW) be stabilized. Because of apparent ease of use and normal structural integrity, cement has been widely used as a binder to solidify LLW. However, the resulting waste forms are sometimes susceptible to failure due to the actions of waste constituents, stress, and environment. This report reviews literature which addresses the effect of microbiologically influenced chemical attack on cement-solidified LLW. Groups of microorganisms are identified, which are capable of metabolically converting organic and inorganic substrates into organic and mineral acids. Such acids aggressively react with concrete and can ultimately lead to structural failure. Mechanisms inherent in microbial-influenced degradation of cement-based material are the focus of this report. This report provides sufficient evidence of the potential for microbial-influenced deterioration of cement-solidified LLW to justify the enumeration of the conditions necessary to support the microbiological growth and population expansion, as well as the development of appropriate tests necessary to determine the resistance of cement-solidified LLW to microbiological-induced degradation that could impact the stability of the waste form

  10. EFFECT OF NANOMATERIALS IN CEMENT MORTAR CHARACTERISTICS

    Directory of Open Access Journals (Sweden)

    WAIL N. AL-RIFAIE

    2016-09-01

    Full Text Available Concrete is considered as brittle materials and widely used due to high compressive strength but unfortunately having and has low tensile strength that has a numerous negative impacts on the lifespan of concrete made structures. Therefore, mechanical properties of cement mortar have been investigated experimentally using different types and ratios of nano material to improve the properties. Since the strength of the concrete is of high importance, different materials have been used to enhance the compressive and the tensile characteristics of the cement mortar compressive and tensile strength. Mainly, this objective has been implemented through using micro cement, micro sand, nano silica, and nano clay in developing a nano-cement mortar which can to improve the concrete for the constructional applications. The samples were prepared and tested under tensile and compressive mode according to ASTM-2011 regulations for concrete. The parameters that are taken consideration during the investigation were micro sand, micro cement, nano silica, developed nano clay, and naphthalene sulphonate as super- plasticizers. In general, it has been observed that the results showed a significant increase in both compressive and tensile strength of the mortar at early stages of hardening, where a maximum increase of 22% in the compressive strength was achieved , whereas 3.7 time increase in the compressive strength was recorded over the tradition levels of the concrete strength.

  11. Properties of pellet cement-glass package

    International Nuclear Information System (INIS)

    Chino, K.; Izumida, T.

    1989-01-01

    A new solidification technique using cement-glass, which is a mixture of sodium silicate, silicon phosphate and cement is presented. It was developed to solidify sodium sulfate or sodium borate pellets generated from nuclear power plants. The optimum composition of Na 2 O, SiO 2 and P 2 O 5 · 2SiO 2 , main components of cement-glass, was defined to be 1:2:1 by studying the solidification mechanism. Polymer impregnated concrete was selected as material of the container to increase the stability. Since the package consists of inorganic materials, it shows good fire resistance and radiation stability. Added cement absorbs free water which is generated by the solidification reaction of Na 2 O, SiO 2 and P 2 O 5 · 2SiO 2 . Then, soluble pellets can be solidified without dissolving some part of them. Since polymer impregnated concrete has little porosity, the pellet cement-glass package which uses a polymer impregnated concrete container shows very low leachability

  12. Plug cementing: Horizontal to vertical conditions

    Energy Technology Data Exchange (ETDEWEB)

    Calvert, D.G.; Heathman, J.F.; Griffith, J.E.

    1995-12-31

    This paper presents an in-depth study of cement plug placement that was conducted with large-scale models for the improvement of plug cementing practices and plug integrity. Common hole and workstring geometries were examined with various rheology and density ratios between the drilling fluid and cement. The critical conditions dictating the difference between success and failure for various wellbore angles and conditions were explored, and the mechanisms controlling slurry movement before and after placement are now better understood. An understanding of these mechanisms allows the engineer to better tailor a design to specific hole conditions. Controversial concepts regarding plug-setting practices have been examined and resolved. The cumulative effects of density, rheology, and hole angle are major factors affecting plug success. While the Boycott effect and an extrusion effect were observed to be predominant in inclined wellbores, a spiraling or {open_quotes}roping{close_quotes} effect controls slurry movement in vertical wellbores. Ultimate success of a cement plug can be obtained if allowances are made for these effects in the job design, provided all other previously published recommended placement practices are followed. Results of this work can be applied to many sidetracking and plug-to-abandon operations. Additionally, the understanding of the fluid movement (creep) mechanisms holds potential for use in primary and remedial cementing work, and in controlling the placement of noncementitious fluids in the wellbore.

  13. Eco-efficiency of the world cement industry: A data envelopment analysis

    International Nuclear Information System (INIS)

    Oggioni, G.; Riccardi, R.; Toninelli, R.

    2011-01-01

    Chemical reactions and the combustion of dirty fuels, such as coal and petroleum coke (petcoke), that are used in cement production processes generate a significant amount of CO 2 emissions. In this paper, we provide an eco-efficiency measure for 21 prototypes of cement industries operating in many countries by applying both a data envelopment analysis (DEA) and a directional distance function approach, which are particularly suitable for models where several production inputs and desirable and undesirable outputs are taken into account. To understand whether this eco-efficiency is due to a rational utilization of inputs or to a real carbon dioxide reduction as a consequence of environmental regulation, we analyze the cases where CO 2 emissions can either be considered as an input or as an undesirable output. Empirical results show that countries where cement industries invest in technologically advanced kilns and adopt alternative fuels and raw materials in their production processes are eco-efficient. This gives a comparative advantage to emerging countries, such as India and China, which are incentivized to modernize their production processes.

  14. Characterization of Two 20kDa-Cement Protein (cp20k) Homologues in Amphibalanus amphitrite

    KAUST Repository

    He, Li-Sheng

    2013-05-22

    The barnacle, Amphibalanus amphitrite, is a common marine fouling organism. Understanding the mechanism of barnacle adhesion will be helpful in resolving the fouling problem. Barnacle cement is thought to play a key role in barnacle attachment. Although several adult barnacle cement proteins have been identified in Megabalanus rosa, little is known about their function in barnacle settlement. In this study, two homologous 20k-cement proteins (cp20k) in Amphibalanus amphitrite, named Bamcp20k-1 and Bamcp20k-2, were characterized. The two homologues share primary sequence structure with proteins from other species including Megabalanus rosa and Fistulobalanus albicostatus. The conserved structure included repeated Cys domains and abundant charged amino acids, such as histidine. In this study we demonstrated that Bamcp20k-1 localized at the α secretory cells in the cyprid cement gland, while Bamcp20k-2 localized to the β secretory cells. The differential localizations suggest differential regulation for secretion from the secretory cells. Both Bamcp20k-1 and Bamcp20k-2 from cyprids dissolved in PBS. However, adult Bamcp20k-2, which was dominant in the basal shell of adult barnacles, was largely insoluble in PBS. Solubility increased in the presence of the reducing reagent Dithiothreitol (DTT), suggesting that the formation of disulfide bonds plays a role in Bamcp20k-2 function. In comparison, Bamcp20k-1, which was enriched in soft tissue, could not be easily detected in the shell and base by Western blot and easily dissolved in PBS. These differential solubilities and localizations indicate that Bamcp20k-1 and Bamcp20k-2 have distinct functions in barnacle cementing. © 2013 He et al.

  15. An Experimental Study of Portland Cement and Superfine Cement Slurry Grouting in Loose Sand and Sandy Soil

    Directory of Open Access Journals (Sweden)

    Weijing Yao

    2018-04-01

    Full Text Available Grouting technology is widely applied in the fields of geotechnical engineering in infrastructure. Loose sand and sandy soil are common poor soils in tunnel and foundation treatments. It is necessary to use superfine cement slurry grouting in the micro-cracks of soil. The different effectiveness of Portland cement slurry and superfine cement slurry in sandy soil by the laboratory grouting experiment method were presented in this paper. The grouting situations of superfine cement slurry injected into sand and sandy soil were explored. The investigated parameters were the dry density, wet density, moisture content, internal friction angle, and cohesion force. The results show that the consolidation effect of superfine cement is better than that of Portland cement due to the small size of superfine cement particles. The superfine cement can diffuse into the sand by infiltration, extrusion, and splitting. When the water–cement ratio of superfine cement slurry is less than 2:1 grouting into loose sand, the dry and wet density decrease with the increase in the water–cement ratio, while the moisture content and cohesive force gradually increase. When the water–cement ratio of superfine cement slurry is 1:1 grouting into loose sand and sandy soil, the dry density, wet density, and cohesive force of loose sand are larger than those of sandy soil. The results of the experiment may be relevant for engineering applications.

  16. Assessment of limestone blended cements for transportation applications : final report.

    Science.gov (United States)

    2017-09-01

    This research assessed the applicability of Type IL cements satisfying AASHTO M 240 specifications for use in transportation applications in place of Type I/II cements which satisfy AASHTO M 85 specifications for construction of transportation struct...

  17. Reducing cement content in concrete mixtures : [research brief].

    Science.gov (United States)

    2011-12-01

    Concrete mixtures contain crushed rock or gravel, and sand, bound together by Portland cement in combination with supplemental cementitious materials (SCMs), which harden through a chemical reaction with water. Portland cement is the most costly comp...

  18. Migration of ions in cement paste as studied by SIMS

    International Nuclear Information System (INIS)

    Prince, K.E.; Aldridge, L.P.; Rougeron, P.

    1998-01-01

    Cement is often used to condition and encapsulate low level radioactive waste before it is disposed of in a repository. Ground water can attack these waste-forms by transporting aggressive ions into the cement paste and by removing radioactive ions from the paste. The extent of the attack will be governed by the diffusion of the ions in the cement paste. In this study we examine the migration of aggressive carbonate ions and inactive Cs and Sr through cement pastes. The use of SIMS for establishing the penetration depths and diffusion profiles for Cs and Sr in cement will be explored. The penetration profiles of Cs and Sr in a non-zeolite cement paste were examined and compared to those of a paste made with zeolite. The effects of the non-homogeneous nature of the cement was most pronounced in the study of the zeolite rich cement; Cs being preferentially accumulated in the zeolite material. (authors)

  19. Effect of aluminium phosphate as admixture on oxychloride cement

    Indian Academy of Sciences (India)

    Abstract. The effect of admixing of aluminium phosphate on oxychloride cement in the matrix has been investigated. It is shown that aluminium phosphate retards the setting process of the cement and improves water-tightness.

  20. Heat of hydration measurements on cemented radioactive wastes. Part 1: cement-water pastes

    International Nuclear Information System (INIS)

    Lee, D.J.

    1983-12-01

    This report describes the hydration of cement pastes in terms of chemical and kinetic models. A calorimetric technique was used to measure the heat of hydration to develop these models. The effects of temperature, water/cement ratio and cement replacements, ground granulated blast furnace slag (BFS) and pulverised fuel ash (PFA) on the hydration of ordinary Portland cement (OPC) is reported. The incorporation of BFS or PFA has a marked effect on the hydration reaction. The effect of temperature is also important but changing the water/cement ratio has little effect. Results from cement pastes containing only water and cement yield total heats of reaction of 400, 200 and 100 kJ/kg for OPC, BFS and PFA respectively. Using the results from the models which have been developed, the effect of major salts present in radioactive waste streams can be assessed. Values of the total heat of reaction, the time to complete 50 percent reaction, and the energy of activation, can be compared for different waste systems. (U.K.)

  1. Characteristics of Portland blast-furnace slag cement containing cement kiln dust and active silica

    Directory of Open Access Journals (Sweden)

    A. Abdel Rahman

    2016-09-01

    Full Text Available This investigation dealt with the effect of active silica, silica fume (SF or rice husk ash (RHA, on the mechanical and physico-chemical characteristics of the hardened blended cement pastes made of Portland blast-furnace slag cement (PSC containing cement kiln dust (CKD cured under normal conditions. Two blends made of PSC and CKD, improved by SF and two blends made of PSC and CKD improved by RHA were investigated. Hardened blended cement pastes were prepared from each cement blend by using water/cement ratio (W/C of 0.30 by weight and hydrated for various curing ages of 1, 3, 7, 28 and 90 days at the normal curing conditions under tap water at room temperature. Each cement paste was tested for its physico-chemical and mechanical characteristics; these characteristics include: compressive strength and kinetics of hydration. The phase composition of the formed hydration products was identified using X-ray diffraction (XRD and differential thermal analysis (DTA. It was found that the partial substitution of PSC by 10% and 15% of CKD is associated with an increase in the rate of hydration and a subsequent improvement of compressive strength of hardened PSC–CKD pastes. In addition, the replacement of PSC, in PSC–CKD blends, by 5% active silica was accompanied by further improvement of the physico-mechanical characteristics of the hardened PSC–CKD pastes.

  2. [The beginning of western medical education].

    Science.gov (United States)

    Kee, C D

    1992-01-01

    Our country had quite an advanced system of medical education during the era of the Koryo Kingdom, and during the Choson Dynasty, the Kyong Guk Dae Jon, in which a systematized medical education was clearly described, was compiled in the era of King Sejong. However, the educational system was not for Western medicine. Western medicine was first introduced to our country in the 9th year of King Injo (1631) when Chong Du Won, Yi Yong Jun, etc. returned from Yon Gyong (Beiuin) with Chik Bang Oe Gi. Knowledge of Western medicine was disseminated by Shil Hak (practical learning) scholars who read a translation in Chinese characters, of Chik Bang Oe Gi. Yi Ik (Song Ho), Yi Gyu Gyong (O ju), Choe Han Gi (Hye Gang), Chong Yak Yong (Ta San), etc., read books of Western medicine and introduced in writing the excellent theory of Western medicine. In addition, Yu Hyong Won (Pan Gye), Pak Ji Won (Yon Am), Pak Je Ga (Cho Jong), etc., showed much interest in Western medicine, but no writings by them about western medicine can be found. With the establishment of a treaty of amity with Japan in the 13th year of King Kojong (1876), followed by the succession of amity treaties with Western powers, foreigners including medical doctors were permitted to flow into this country. At that time, doctors Horace N. Allen, W. B. Scranton, John W. Heron, Rosetta Sherwood (Rosetta S. Hall), etc., came to Korea and inaugurated hospitals, where they taught Western medicine to Korean students. Dr. Horace N. Allen, with the permission of king Kojong, established Che Jung Won in April 1885, and in March 1886, he began at the hospital to provide education of Western medicine to Korean students who were recrutied by the Korean Government. However, the education was not conduted on a regular basis, only training them for work as assistants. This is considered to be the pioneer case of Western medical education in this country. Before that time, Japanese medical doctors came to Korea, but there are no

  3. STUDY OF FUNCTIONAL RESULTS OF CEMENTED TOTAL HIP REPLACEMENT BY MOORE’S APPROACH

    Directory of Open Access Journals (Sweden)

    Arunim

    2016-02-01

    Full Text Available INTRODUCTION The total hip replacement (THR has probably become the surgical procedure of choice for vide variety of hip joint disabling diseases. The prosthesis used for THR is often grouped into cemented, cement-less and hybrid ones. There has been increasing trends in use of cement-less components citing more number of complications namely loosening, increased infection rate etc. however with additional cost factors as well. We conducted this study to ascertain whether in a developing country like ours should we really switch over to un-cemented hip replacements dreading such complications or can we still use cemented prosthesis with equally good if not better results. METHODS A study of functional results of cemented total hip replacement was done in patients with varied age groups ranging from 40 years to 75 years with the average age being 54.8 years. 20 patients with 21 diseased hips were treated with cemented total hip replacement by Moore’s posterior approach at NSCB Subharti medical college, Meerut, UP from December 2010 to December 2013 and reviewed thereafter with an average follow-up period of 4.2 years. Average surgical time required was one and half hour. Patients were asked to come for follow up on 1st month, 3rd month and 6th month and then every 6 months and were assessed as per modified Harris Hip Score. RESULTS All the patients were evaluated according to the Modified Harris Hip Scoring system. The results showed 14(67% hips with excellent results, 4(19% with good results, and 3(14% hips with fair results. No poor outcome was noted in this study. 2 cases of dislocation (10% were noted one on the 5th post-operative day and the other occurred after the patient was discharged from the institution. CONCLUSIONS The management of diseased and destroyed hips with chronic pain with cemented total hip replacement is effective and gives stable, mobile and painless hip joint to the patient. Functional results are excellent and

  4. Experimental techniques for cement hydration studies

    Directory of Open Access Journals (Sweden)

    Andreas Luttge

    2011-10-01

    Full Text Available Cement hydration kinetics is a complex problem of dissolution, nucleation and growth that is still not well understood, particularly in a quantitative way. While cement systems are unique in certain aspects they are also comparable to natural mineral systems. Therefore, geochemistry and particularly the study of mineral dissolution and growth may be able to provide insight and methods that can be utilized in cement hydration research. Here, we review mainly what is not known or what is currently used and applied in a problematic way. Examples are the typical Avrami approach, the application of Transition State Theory (TST to overall reaction kinetics and the problem of reactive surface area. Finally, we suggest an integrated approach that combines vertical scanning interferometry (VSI with other sophisticated analytical techniques such as atomic force microscopy (AFM and theoretical model calculations based on a stochastic treatment.

  5. Cementation of wastes with boric acid

    International Nuclear Information System (INIS)

    Tello, Cledola C.O.; Haucz, Maria Judite A.; Alves, Lilian J.L.; Oliveira, Arno H.

    2000-01-01

    In nuclear power plants (PWR) are generated wastes, such as concentrate, which comes from the evaporation of liquid radioactive wastes, and spent resins. Both have boron in their composition. The cementation process is one of the options to solidify these wastes, but the boron has a negative effect on the setting of the cement mixture. In this paper are presented the experiments that are being carried out in order to overcome this problem and also to improve the efficiency of the process. Simulated wastes were cemented using additives (clays, admixtures etc.). In the process and product is being evaluated the effect of the amount, type and addition order of the materials. The mixtures were selected in accordance with their workability and incorporated waste. The solidified products are monolithic without free water with a good mechanical resistance. (author)

  6. CO2 Capture for Cement Technology

    DEFF Research Database (Denmark)

    Pathi, Sharat Kumar

    ppmvin 1960 to 390 ppmv in 2012, probably due to human activity. A lot of research is being carried out forreducing CO2emissions from large stationary sources. Ofwhich, the carbonate looping process is anew process and has the potential to reduce CO2emissions with lower energy penalties. Most of thework...... and the main parameter that controls the performance of the carbonator, a process model integrating the carbonate looping process with the cement pyro-process was simulated. The process simulation results indicate that the CO2 emission was only 0.07 kg/ kg cl, with an energy penalty of 2 MJ/kg CO2 captured......Production of cement is an energy intensive process and is the source of considerable CO2emissions. Itis estimated that the cement industry contributes around 8% of total global CO2emissions. CO2is oneof the major greenhouse gases. In the atmosphere, the CO2concentration has increased from 310...

  7. Mechanical characterization of sisal reinforced cement mortar

    Directory of Open Access Journals (Sweden)

    R. Fujiyama

    2014-01-01

    Full Text Available This work aims at evaluating the mechanical behavior of sisal fiber reinforced cement mortar. The composite material was produced from a mixture of sand, cement, and water. Sisal fibers were added to the mixture in different lengths. Mechanical characterization of both the composite and the plain mortar was carried out using three point bend, compression, and impact tests. Specimens containing notches of different root radii were loaded in three point bending in an effort to determine the effect of the fibers on the fracture toughness of the material. The results obtained indicate that, while fiber reinforcement leads to a decrease in compressive strength, J-integral calculations at maximum load for the different notch root radii have indicated, particularly for the case of long fibers, a significant superiority of the reinforced material in comparison with the plain cement mortar, in consistence with the impact test data.

  8. Pore structure in blended cement pastes

    DEFF Research Database (Denmark)

    Canut, Mariana Moreira Cavalcanti

    Supplementary cementitious materials (SCMs), such as slag and fly ash, are increasingly used as a substitute for Portland cement in the interests of improvement of engineering properties and sustainability of concrete. According to studies improvement of engineering properties can be explained...... supplement each other. Cement pastes (w/b=0.4) with and without slag and fly ash cured at two moisture (sealed and saturated) and temperature (20 and 55ºC) conditions were used to investigate the combined impact of SCMs addition and curing on the pore structure of pastes cured up to two years. Also...... volume and threshold pore size were found when comparing with plain cement paste at the same curing conditions. The porosity methods MIP, LTC and SEM have been shown to be suitable to characterise pore parameters of the pastes. MIP is a simple and fast method which covers a large range of pore sizes...

  9. Revision of hemiarthroplasty to total hip arthroplasty using the cement-in-cement technique.

    Science.gov (United States)

    Mounsey, E J; Williams, D H; Howell, J R; Hubble, M J

    2015-12-01

    Revision of a cemented hemiarthroplasty of the hip may be a hazardous procedure with high rates of intra-operative complications. Removing well-fixed cement is time consuming and risks damaging already weak bone or perforating the femoral shaft. The cement-in-cement method avoids removal of intact cement and has shown good results when used for revision total hip arthroplasty (THA). The use of this technique for the revision of a hemiarthroplasty to THA has not been previously reported. A total of 28 consecutive hemiarthroplasties (in 28 patients) were revised to a THA using an Exeter stem and the cement-in-cement technique. There were four men and 24 women; their mean age was 80 years (35 to 93). Clinical and radiographic data, as well as operative notes, were collected prospectively and no patient was lost to follow-up. Four patients died within two years of surgery. The mean follow up of the remainder was 70 months (25 to 124). Intra-operatively there was one proximal perforation, one crack of the femoral calcar and one acetabular fracture. No femoral components have required subsequent revision for aseptic loosening or are radiologically loose. Four patients with late complications (14%) have since undergone surgery (two for a peri-prosthetic fracture, and one each for deep infection and recurrent dislocation) resulting in an overall major rate of complication of 35.7%. The cement-in-cement technique provides reliable femoral fixation in this elderly population and may reduce operating time and rates of complication. ©2015 The British Editorial Society of Bone & Joint Surgery.

  10. Cementation of the solid radioactive waste with polymer-cement solutions using the method of impregnation

    International Nuclear Information System (INIS)

    Gorbunova, O.

    2015-01-01

    Cementation of solid radioactive waste (SRW), i.e. inclusion of solid radioactive waste into cement matrix without cavities - is one of the main technological processes used for conditioning low and intermediate level radioactive waste. At FSUE 'Radon' the industrialized method of impregnation has been developed and since 2003 has been using for cementation of solid radioactive waste. The technology is that the polymer-cement solution, having high penetrating properties, is supplied under pressure through a tube to the bottom of the container in which solid radioactive waste has preliminarily been placed. The polymer-cement solution is evenly moving upwards through the channels between the particles of solid radioactive waste, fills the voids in the bulk volume of the waste and hardens, forming a cement compound, the amount of which is equal to the original volume. The aim of the investigation was a selection of a cement solution suitable for SRW impregnation (including fine particles) without solution depletion and bottom layers stuffing. It has been chosen a polymer: PHMG (polyhexamethylene-guanidine), which is a stabilizing and water-retaining component of the cement solution. The experiments confirm that the polymer increases the permeability of the cement solution by a 2-2.5 factor, the viscosity by a 1.2 factor, the stability of the consistency by a 1.5-1.7 factor, and extends the operating range of the W/C ratio to 0.5-1.1. So it is possible to penetrate a volume of SRW bigger by a 1.5-2.0 factor. It has been proved, that PHMG polymer increases strength and frost-resistance of the final compounds by a 1.8-2.7 factor, and contributes to fast strength development at the beginning of hardening and it decreases Cs-137 leashing rate by a 1.5-2 factor

  11. Comparison of modified sulfur cement and hydraulic cement for encapsulation of radioactive and mixed wastes

    International Nuclear Information System (INIS)

    Kalb, P.D.; Heiser, J.H. III; Colombo, P.

    1990-01-01

    The majority of solidification/stabilization systems for low-level radioactive waste (LLW) and mixed waste, both in the commercial sector and at Department of Energy (DOE) facilities, utilize hydraulic cement (such as portland cement) to encapsulate waste materials and yield a monolithic solid waste form for disposal. Because hydraulic cement requires a chemical hydration reaction for setting and hardening, it is subject to potential interactions between elements in the waste and binder that can retard or prevent solidification. A new and innovative process utilizing modified sulfur cement developed by the US Bureau of Mines has been applied at Brookhaven National Laboratory (BNL) for the encapsulation of many of these problem wastes. Modified sulfur cement is a thermoplastic material, and as such, it can be heated above its melting point, combined with dry waste products to form a homogeneous mixture, and cooled to form a monolithic solid product. Under sponsorship of the DOE, research and development efforts at BNL have successfully applied the modified sulfur cement process for treatment of a range of LLWs including sodium sulfate salts, boric acid salts, and incinerator bottom ash and for mixed waste contaminated incinerator fly ash. Process development studies were conducted to determine optimal waste loadings for each waste type. Property evaluation studies were conducted to test waste form behavior under disposal conditions by applying relevant performance testing criteria established by the Nuclear Regulatory Commission (for LLW) and the Environmental Protection Agency (for hazardous wastes). Based on both processing and performance considerations, significantly greater waste loadings were achieved using modified sulfur cement when compared with hydraulic cement. Technology demonstration of the modified sulfur cement encapsulation system using production-scale equipment is scheduled for FY 1991

  12. Application of glass ionomer cements in restorative dentistry.

    OpenAIRE

    Rajesh P; Kamath M

    1999-01-01

    Dentistry was marked with radical changes in clinical restorative procedures. If the inherent characteristic of the ionomer cement was examined, it becomes very clear to the researcher as well as the dentist, that no other material has had an impact as comparable to glass ionomer cements on restorative dentistry. This scientific paper highlights the clinical applications of the cement in restorative dentistry. Glass ionomer cements are bioactive, by forming permanent adhesive bonds to dentin ...

  13. Retention of cast crown copings cemented to implant abutments.

    Science.gov (United States)

    Dudley, J E; Richards, L C; Abbott, J R

    2008-12-01

    The cementation of crowns to dental implant abutments is an accepted form of crown retention that requires consideration of the properties of available cements within the applied clinical context. Dental luting agents are exposed to a number of stressors that may reduce crown retention in vivo, not the least of which is occlusal loading. This study investigated the influence of compressive cyclic loading on the physical retention of cast crown copings cemented to implant abutments. Cast crown copings were cemented to Straumann synOcta titanium implant abutments with three different readily used and available cements. Specimens were placed in a humidifier, thermocycled and subjected to one of four quantities of compressive cyclic loading. The uniaxial tensile force required to remove the cast crown copings was then recorded. The mean retention values for crown copings cemented with Panavia-F cement were statistically significantly greater than both KetacCem and TempBond non-eugenol cements at each compressive cyclic loading quantity. KetacCem and TempBond non-eugenol cements produced relatively low mean retention values that were not statistically significantly different at each quantity of compressive cyclic loading. Compressive cyclic loading had a statistically significant effect on Panavia-F specimens alone, but increased loading quantities produced no further statistically significant difference in mean retention. Within the limitations of the current in vitro conditions employed in this study, the retention of cast crown copings cemented to Straumann synOcta implant abutments with a resin, glass ionomer and temporary cement was significantly affected by cement type but not compressive cyclic loading. Resin cement is the cement of choice for the definitive non-retrievable cementation of cast crown copings to Straumann synOcta implant abutments out of the three cements tested.

  14. Expansion control for cementation of incinerated ash

    International Nuclear Information System (INIS)

    Nakayama, T.; Suzuki, S.; Hanada, K.; Tomioka, O.; Sato, J.; Irisawa, K.; Kato, J.; Kawato, Y.; Meguro, Y.

    2015-01-01

    A method, in which incinerated ash is solidified with a cement material, has been developed to dispose of radioactive incinerated ash waste. A small amount of metallic Al, which was not oxidized in the incineration, existed in the ash. When such ash was mixed with a cement material and water, alkaline components in the ash and the cement were dissolved in the mixing water and then metallic Al reaction with the alkaline compounds resulted in generation of H 2 . Because the H 2 generation began immediately just after the mixing, H 2 bubbles pushed up the mixed grout material and an expanded solidified form was obtained. The expansion leads to lowering the strength of the solidified form and making harmful void. In this study, we tried to control H 2 generation from the reaction of metallic Al in the cementation by means of following two methods, one was a method to let metallic Al react prior to the cementation and the other was a method to add an expansion inhibitor that made an oxide film on the surface of metallic Al. In the pre-treatment, the ash was soaked in water in order to let metallic Al react with it, and then the ash with the immersion solution was dried at 105 Celsius degrees. The pre-treated ash was mixed with an ordinary portland cement and water. The inhibitor of lithium nitrite, sodium nitrite, phosphoric acid, or potassium dihydrogen phosphate was added at the mixing process. The solidified forms prepared using the pre-treated ash and lithium nitrite were not expanded. Phosphoric acid and sodium nitrite were effective for expansion control, but potassium dihydrogen phosphate did not work. (authors)

  15. Crowns cemented on crown preparations lacking geometric resistance form. Part II: effect of cement.

    Science.gov (United States)

    Proussaefs, Periklis

    2004-03-01

    This study evaluated the effect of different cements on resistance to dislodgment of crowns cemented on preparations lacking geometric resistance form. A preparation that offered no geometric resistance form, with 20 degrees total occlusal convergence (TOC), 0.9 mm wide shoulder finish line, and a 2.5 mm axial wall height was created on an ivorine tooth using a milling machine. Ten metal test specimen die replicas and 10 standardized metal crowns with recipient sites for the application of external forces through a universal testing machine were fabricated. The crowns were cemented on the dies under 5 and 10 kg external loads, the marginal openings measured, loaded to dislodgment, and cleaned of cement. The process was repeated using zinc oxide and eugenol (ZOE), zinc phosphate (ZPh), resin modified glass ionomer (RMGI), and composite resin (CR) cements. Marginal openings under 5 kg cementation loads were 74.63 (+/-15.04) for ZOE, 75.98 (+/-18.20) microm for ZPh, 98.58 (+/-22.62) microm for RMGI, and 105.82 (+/-20.07) microm for CR cements respectively; under 10 kg cementation loads they were 57.62 (+/-15.86) microm, 59.55 (+/-15.41) microm, 95.00 (+/-19.52) microm, 101.30 (+/-12.52) microm respectively. Oblique dislodgment forces, measured with a Universal testing machine, were 40.18 (+/- 6.76) N for ZOE, 215.65 (+/-45.79) N for ZPh, 165.43 (+/-19.53) N for RMGI, and 181.54 (+/-30.75) N for CR respectively when crowns were cemented under 5 kg loads. The corresponding values for 10 kg loads were 38.62 (+/-4.19), 274.86 (+/-54.22), 139.70 (+/-21.71), and 160.40 (+/-21.21) respectively. Only zinc phosphate cement produced statistically enhanced resistance when crowns were cemented under 10 kg force (p value = 0.035). Under the conditions of the present study only crowns cemented with zinc phosphate displayed increased resistance to dislodgment on preparations lacking resistance form.

  16. Quality control of cemented waste forms

    International Nuclear Information System (INIS)

    Slate, L.J.; Wacks, M.E.; Cornellissen, H.A.W.

    1994-01-01

    Seven day and 28 day compressive strength from radwaste cementation can be predicted during the mixing and early curing stages by at least three methods: maturity, rheology, and impedance. Best results were obtained via the impedance method, where the water-to-cement ratio was seen to be the primary factor. The rheology method produced physically consistent results, but may be to cumbersome to be practical. The results of the maturity method were shown to be limited in its accuracy for determining compressive strength

  17. Controls on Cementation in a Chalk Reservoir

    DEFF Research Database (Denmark)

    Meireles, Leonardo Teixeira Pinto; Hussein, A.; Welch, M.J.

    In this study, we identify different controls on cementation in a chalk reservoir. Biot’s coefficient, a measure of cementation, stiffness and strength in porous rocks, is calculated from logging data (bulk density and sonic Pwave velocity). We show that Biot’s coefficient is correlated...... to the water saturation of the Kraka reservoir and is partly controlled by its stratigraphic sub-units. While the direct causal relationship between Biot’s coefficient and water saturation cannot be extended for Biot’s coefficient and porosity, a correlation is also identified between the two, implying...

  18. Durability of pulp fiber-cement composites

    Science.gov (United States)

    Mohr, Benjamin J.

    Wood pulp fibers are a unique reinforcing material as they are non-hazardous, renewable, and readily available at relatively low cost compared to other commercially available fibers. Today, pulp fiber-cement composites can be found in products such as extruded non-pressure pipes and non-structural building materials, mainly thin-sheet products. Although natural fibers have been used historically to reinforce various building materials, little scientific effort has been devoted to the examination of natural fibers to reinforce engineering materials until recently. The need for this type of fundamental research has been emphasized by widespread awareness of moisture-related failures of some engineered materials; these failures have led to the filing of national- and state-level class action lawsuits against several manufacturers. Thus, if pulp fiber-cement composites are to be used for exterior structural applications, the effects of cyclical wet/dry (rain/heat) exposure on performance must be known. Pulp fiber-cement composites have been tested in flexure to examine the progression of strength and toughness degradation. Based on scanning electron microscopy (SEM), environmental scanning electron microscopy (ESEM), energy dispersive spectroscopy (EDS), a three-part model describing the mechanisms of progressive degradation has been proposed: (1) initial fiber-cement/fiber interlayer debonding, (2) reprecipitation of crystalline and amorphous ettringite within the void space at the former fiber-cement interface, and (3) fiber embrittlement due to reprecipitation of calcium hydroxide filling the spaces within the fiber cell wall structure. Finally, as a means to mitigate kraft pulp fiber-cement composite degradation, the effects of partial portland cement replacement with various supplementary cementitious materials (SCMs) has been investigated for their effect on mitigating kraft pulp fiber-cement composite mechanical property degradation (i.e., strength and toughness

  19. ASSESSMENT OF DEFORMATION AND STRENGTH OF SOILS STRENGTHENED BY CEMENTING

    Directory of Open Access Journals (Sweden)

    Sainov Mihail Petrovich

    2014-09-01

    Full Text Available Currently there are few studies of deformation and strength properties of loose soils strengthened by cementing. Based on the data of already arranged grout curtains it was determined that in cemented gravel-pebble soil there are 7...9 % of cement, which is less than in concrete. To assess deformation and strength of such soils it is possible to use the data of tests conducted by other authors, where the effect of cement contents on sand-cement mix properties was studied. Analysis of experimental data showed that cemented soil may be identified with concrete only with high content of cement (more than 10 %. At cement content 7...9 % in soil the strength deformation of cemented soil varies to a small extent. Its deformation becomes 2-3 times less. It greatly depends on compression stresses. The formulae are proposed which permit assessing the effect of compression and cement content on deformation of cemented soil. It is shown that strength of cemented soil is less than that even of the weakest concrete. It has a sufficiently high cohesion, but the friction angle is approximately the same as that of the initial soil.

  20. Geotechnical properties of clayey soil stabilized with cement ...

    African Journals Online (AJOL)

    The study was conducted to investigate the different effects of cement-sawdust ash and cement on a clayey soil sampled from Mandate Lodge, Landmark University, Omu-Aran, Nigeria. The binder mix of cementsawdust ash (CSDA) was mixed in a ratio of 1:1. The CSDA and cement were added to the soil samples at ...

  1. Effect of aluminium phosphate as admixture on oxychloride cement

    Indian Academy of Sciences (India)

    Unknown

    Oxychloride cement (magnesia cement) has many superior properties to that of portland cement (Sorel 1867; Beau- din and Ramachandra 1975; Beaudin et al 1977). The chemical composition of the additive or admixture availa- ble in commercial grade is AlPO4. Little scientific data are available about its effect on ...

  2. 21 CFR 888.4220 - Cement monomer vapor evacuator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cement monomer vapor evacuator. 888.4220 Section... (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4220 Cement monomer vapor evacuator. (a) Identification. A cement monomer vapor evacuator is a device intended for use during surgery to contain or remove...

  3. Development of hydroxyapatite bone cement for controlled drug ...

    Indian Academy of Sciences (India)

    ... difference could be detected in XRD patterns of the TCH–HA cement with various amounts of drug. By increasing the drug concentration, mechanical strength of cement was decreased and its setting time was increased. The results of this study demonstrate the potential of using HA cement as a carrier for drug delivery.

  4. Computation of X-ray powder diffractograms of cement components ...

    Indian Academy of Sciences (India)

    Computation of X-ray powder diffractograms of cement components and its application to phase analysis and hydration performance of OPC cement. Rohan Jadhav N C Debnath. Volume 34 Issue 5 August 2011 pp 1137- ... Keywords. Portland cement; X-ray diffraction; crystal structure; characterization; Rietveld method.

  5. Assessment of Pollution Potentialities of some Portland Cement ...

    African Journals Online (AJOL)

    Chemical analysis of some Portland cement commonly used in Nigeria was carried out. All the cement studies were found to be good for concrete work especially where no special property is required. The concentration levels of heavy metals in all the cement samples were above the tolerance limit and therefore need to ...

  6. Radiopacity of portland cement associated with different radiopacifying agents.

    Science.gov (United States)

    Húngaro Duarte, Marco Antonio; de Oliveira El Kadre, Guâniara D'arc; Vivan, Rodrigo Ricci; Guerreiro Tanomaru, Juliane Maria; Tanomaru Filho, Mário; de Moraes, Ivaldo Gomes

    2009-05-01

    This study evaluated the radiopacity of Portland cement associated with the following radiopacifying agents: bismuth oxide, zinc oxide, lead oxide, bismuth subnitrate, bismuth carbonate, barium sulfate, iodoform, calcium tungstate, and zirconium oxide. A ratio of 20% radiopacifier and 80% white Portland cement by weight was used for analysis. Pure Portland cement and dentin served as controls. Cement/radiopacifier and dentin disc-shaped specimens were fabricated, and radiopacity testing was performed according to the ISO 6876/2001 standard for dental root sealing materials. Using Insight occlusal films, the specimens were radiographed near to a graduated aluminum stepwedge varying from 2 to 16 mm in thickness. The radiographs were digitized and radiopacity compared with the aluminum stepwedge using Digora software (Orion Corporation Soredex, Helsinki, Finland). The radiographic density data were converted into mmAl and analyzed statistically by analysis of variance and Tukey-Kramer test (alpha = 0.05). The radiopacity of pure Portland cement was significantly lower (p cement/radiopacifier mixtures were significantly more radiopaque than dentin and Portland cement alone (p Portland cement/bismuth oxide and Portland cement/lead oxide presented the highest radiopacity values and differed significantly from the other materials (p Portland cement/zinc oxide presented the lowest radiopacity values of all mixtures (p Portland cement as radiopacifying agents. However, the possible interference of the radiopacifiers with the setting chemistry, biocompatibility, and physical properties of the Portland cement should be further investigated before any clinical recommendation can be done.

  7. The Suitability of Lime Rice Husk Ash Cement as Construction ...

    African Journals Online (AJOL)

    However, by gradually increasing the percentage contents of silica, potassium oxide and sodium oxide in the Portland cement to the values found in the rice husk ash a new product, "Artificial Lime Rice Husk Ash" (ALRHA) cement was produced. The new product ALRHA cement compared favourably with the ordinary rice ...

  8. CEMENT KILN DUST AS A MATERIAL FOR BUILDING BLOCKS ...

    African Journals Online (AJOL)

    This paper presents the results of a study on the properties of hollow sandcrete blocks with cement kiln dust (CKD) as an additive and as a replacement for ordinary portland cement (OPC). When CKD was used as a replacement for cement, the compressive strength and density of blocks generally decreased with higher ...

  9. 透過PISA與TIMSS評比研究檢視西方與亞洲學生數學的相對強項 Using PISA and TIMSS Mathematics Assessments to Identify the Relative Strengths of Students in Western and Asian Countries

    Directory of Open Access Journals (Sweden)

    張立民 Margaret Wu

    2011-03-01

    Full Text Available Wu(2009)的研究曾將2003 年「國際學生能力評量計畫」(Programme for International Student Assessment, PISA)的數學表現,與「國際數學與科學教育成就趨勢調查」(Trends in International Mathematics and Science Study, TIMSS)八年級學生的數學表現做一比較,結果發現,西方國家在PISA 的表現大致上比在TIMSS的表現為佳。本研究則將TIMSS公開的題目分為兩組,一組與PISA 的架構相符,另一組則不相符。其中,TIMSS評比有很多幾何與代數的題目是屬於「純粹的數學」題(即未以真實生活情境作為背景的數學題),而這些題目並未出現在PISA 評比之中。本研究檢視六個國家在這兩組題目表現上的差異,藉此反映出西方與亞洲國家的相對強項與弱點,接著再將這些強項與弱點連結到PISA與TIMSS評比的內容上。有證據顯示,西方與亞洲國家在PISA 與TIMSS的差異表現可歸因於兩評比題目種類的不同。 A study was carried out that compared Programme for International Student Assessment (PISA 2003 Mathematics results with Trends in International Mathematics and Science Study (TIMSS 2003 Grade 8 Mathematics results (Wu, 2009. It was found that Western countries generally performed better in PISA than in TIMSS, and Eastern European and Asian countries generally performed better in TIMSS than in PISA. In this paper, TIMSS released items are divided into two sets: one that fits the PISA framework and one that does not. In particular, many geometry and algebra items in TIMSS are “inner mathematics” (mathematics without a real-life context, and such items do not appear in the PISA test. Differential performances of six countries on each set of items are examined. In this way, the relative strengths and weaknesses of Western and Asian countries are identified. These strengths and weaknesses are then linked back to the contents of the PISA and TIMSS

  10. A comparison of retentive strength of implant cement depending on various methods of removing provisional cement from implant abutment

    OpenAIRE

    Keum, Eun-Cheol; Shin, Soo-Yeon

    2013-01-01

    PURPOSE This study evaluated the effectiveness of various methods for removing provisional cement from implant abutments, and what effect these methods have on the retention of prosthesis during the definitive cementation. MATERIALS AND METHODS Forty implant fixture analogues and abutments were embedded in resin blocks. Forty cast crowns were fabricated and divided into 4 groups each containing 10 implants. Group A was cemented directly with the definitive cement (Cem-Implant). The remainder ...

  11. Determining the water-cement ratio, cement content, water content and degree of hydration of hardened cement paste: Method development and validation on paste samples

    International Nuclear Information System (INIS)

    Wong, H.S.; Buenfeld, N.R.

    2009-01-01

    We propose a new method to estimate the initial cement content, water content and free water/cement ratio (w/c) of hardened cement-based materials made with Portland cements that have unknown mixture proportions and degree of hydration. This method first quantifies the composition of the hardened cement paste, i.e. the volumetric fractions of capillary pores, hydration products and unreacted cement, using high-resolution field emission scanning electron microscopy (FE-SEM) in the backscattered electron (BSE) mode and image analysis. From the obtained data and the volumetric increase of solids during cement hydration, we compute the initial free water content and cement content, hence the free w/c ratio. The same method can also be used to calculate the degree of hydration. The proposed method has the advantage that it is quantitative and does not require comparison with calibration graphs or reference samples made with the same materials and cured to the same degree of hydration as the tested sample. This paper reports the development, assumptions and limitations of the proposed method, and preliminary results from Portland cement pastes with a range of w/c ratios (0.25-0.50) and curing ages (3-90 days). We also discuss the extension of the technique to mortars and concretes, and samples made with blended cements.

  12. A comparison of retentive strength of implant cement depending on various methods of removing provisional cement from implant abutment.

    Science.gov (United States)

    Keum, Eun-Cheol; Shin, Soo-Yeon

    2013-08-01

    This study evaluated the effectiveness of various methods for removing provisional cement from implant abutments, and what effect these methods have on the retention of prosthesis during the definitive cementation. Forty implant fixture analogues and abutments were embedded in resin blocks. Forty cast crowns were fabricated and divided into 4 groups each containing 10 implants. Group A was cemented directly with the definitive cement (Cem-Implant). The remainder were cemented with provisional cement (Temp-Bond NE), and classified according to the method for cleaning the abutments. Group B used a plastic curette and wet gauze, Group C used a rubber cup and pumice, and Group D used an airborne particle abrasion technique. The abutments were observed using a stereomicroscope after removing the provisional cement. The tensile bond strength was measured after the definitive cementation. Statistical analysis was performed using one-way analysis of variance test (α=.05). Group B clearly showed provisional cement remaining, whereas the other groups showed almost no cement. Groups A and B showed a relatively smooth surface. More roughness was observed in Group C, and apparent roughness was noted in Group D. The tensile bond strength tests revealed Group D to have significantly the highest tensile bond strength followed in order by Groups C, A and B. A plastic curette and wet gauze alone cannot effectively remove the residual provisional cement on the abutment. The definitive retention increased when the abutments were treated with rubber cup/pumice or airborne particle abraded to remove the provisional cement.

  13. Comparative evaluation of marginal leakage of provisional crowns cemented with different temporary luting cements: In vitro study

    Directory of Open Access Journals (Sweden)

    Sheen Juneja Arora

    2016-01-01

    Conclusion: The temporary cements with eugenol showed more microleakage than those without eugenol. SC-10 crowns showed more microleakage compared to Protemp 4 crowns. SC-10 crowns cemented with Kalzinol showed maximum microleakage and Protemp 4 crowns cemented with HY bond showed least microleakage.

  14. The suitability of a supersulfated cement for nuclear waste immobilisation

    Energy Technology Data Exchange (ETDEWEB)

    Collier, N.C., E-mail: nick.collier@sheffield.ac.uk [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom); Milestone, N.B. [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom); Callaghan Innovation, 69 Gracefield Road, PO Box 31310, Lower Hutt 5040 (New Zealand); Gordon, L.E. [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom); Geopolymer and Minerals Processing Group, Department of Chemical and Biomolecular Engineering, University of Melbourne, Parkville, Victoria 3010 (Australia); Ko, S.-C. [Holcim Technology Ltd, Hagenholzstrasse 85, CH-8050 Zurich (Switzerland)

    2014-09-15

    Highlights: • We investigate a supersulfated cement for use as a nuclear waste encapsulant. • High powder fineness requires a high water content to satisfy flow requirements. • Heat generation during hydration is similar to a control cement paste. • Typical hydration products are formed resulting in a high potential for waste ion immobilisation. • Paste pH and aluminium corrosion is less than in a control cement paste. - Abstract: Composite cements based on ordinary Portland cement are used in the UK as immobilisation matrices for low and intermediate level nuclear wastes. However, the high pore solution pH causes corrosion of some metallic wastes and undesirable expansive reactions, which has led to alternative cementing systems being examined. We have investigated the physical, chemical and microstructural properties of a supersulfated cement in order to determine its applicability for use in nuclear waste encapsulation. The hardened supersulfated cement paste appeared to have properties desirable for use in producing encapsulation matrices, but the high powder specific surface resulted in a matrix with high porosity. Ettringite and calcium silicate hydrate were the main phases formed in the hardened cement paste and anhydrite was present in excess. The maximum rate of heat output during hydration of the supersulfated cement paste was slightly higher than that of a 9:1 blastfurnace slag:ordinary Portland cement paste commonly used by the UK nuclear waste processing industry, although the total heat output of the supersulfated cement paste was lower. The pH was also significantly lower in the supersulfated cement paste. Aluminium hydroxide was formed on the surface of aluminium metal encapsulated in the cement paste and ettringite was detected between the aluminium hydroxide and the hardened cement paste.

  15. Development of an Improved Cement for Geothermal Wells

    Energy Technology Data Exchange (ETDEWEB)

    Trabits, George [Trabits Group, LLC, Wasilla, AK (United States)

    2015-04-20

    After an oil, gas, or geothermal production well has been drilled, the well must be stabilized with a casing (sections of steel pipe that are joined together) in order to prevent the walls of the well from collapsing. The gap between the casing and the walls of the well is filled with cement, which locks the casing into place. The casing and cementing of geothermal wells is complicated by the harsh conditions of high temperature, high pressure, and a chemical environment (brines with high concentrations of carbon dioxide and sulfuric acid) that degrades conventional Portland cement. During the 1990s and early 2000s, the U.S. Department of Energy’s Geothermal Technologies Office (GTO) provided support for the development of fly-ash-modified calcium aluminate phosphate (CaP) cement, which offers improved resistance to degradation compared with conventional cement. However, the use of CaP cements involves some operational constraints that can increase the cost and complexity of well cementing. In some cases, CaP cements are incompatible with chemical additives that are commonly used to adjust cement setting time. Care must also be taken to ensure that CaP cements do not become contaminated with leftover conventional cement in pumping equipment used in conventional well cementing. With assistance from GTO, Trabits Group, LLC has developed a zeolite-containing cement that performs well in harsh geothermal conditions (thermal stability at temperatures of up to 300°C and resistance to carbonation) and is easy to use (can be easily adjusted with additives and eliminates the need to “sterilize” pumping equipment as with CaP cements). This combination of properties reduces the complexity/cost of well cementing, which will help enable the widespread development of geothermal energy in the United States.

  16. The suitability of a supersulfated cement for nuclear waste immobilisation

    International Nuclear Information System (INIS)

    Collier, N.C.; Milestone, N.B.; Gordon, L.E.; Ko, S.-C.

    2014-01-01

    Highlights: • We investigate a supersulfated cement for use as a nuclear waste encapsulant. • High powder fineness requires a high water content to satisfy flow requirements. • Heat generation during hydration is similar to a control cement paste. • Typical hydration products are formed resulting in a high potential for waste ion immobilisation. • Paste pH and aluminium corrosion is less than in a control cement paste. - Abstract: Composite cements based on ordinary Portland cement are used in the UK as immobilisation matrices for low and intermediate level nuclear wastes. However, the high pore solution pH causes corrosion of some metallic wastes and undesirable expansive reactions, which has led to alternative cementing systems being examined. We have investigated the physical, chemical and microstructural properties of a supersulfated cement in order to determine its applicability for use in nuclear waste encapsulation. The hardened supersulfated cement paste appeared to have properties desirable for use in producing encapsulation matrices, but the high powder specific surface resulted in a matrix with high porosity. Ettringite and calcium silicate hydrate were the main phases formed in the hardened cement paste and anhydrite was present in excess. The maximum rate of heat output during hydration of the supersulfated cement paste was slightly higher than that of a 9:1 blastfurnace slag:ordinary Portland cement paste commonly used by the UK nuclear waste processing industry, although the total heat output of the supersulfated cement paste was lower. The pH was also significantly lower in the supersulfated cement paste. Aluminium hydroxide was formed on the surface of aluminium metal encapsulated in the cement paste and ettringite was detected between the aluminium hydroxide and the hardened cement paste

  17. Preparation and characterization of a novel bioactive bone cement: glass based nanoscale hydroxyapatite bone cement.

    Science.gov (United States)

    Fu, Qiang; Zhou, Nai; Huang, Wenhai; Wang, Deping; Zhang, Liying; Li, Haifeng

    2004-12-01

    A novel type of glass-based nanoscale hydorxypatite (HAP) bioactive bone cement (designed as GBNHAPC) was synthesized by adding nanoscale hydroxyapatite (HAP) crystalline (20-40 nm), into the self-setting glass-based bone cement (GBC). The inhibition rate of nanoscale HAP and micron HAP on osteosarcoma U2-OS cells was examined. The effects of nanoscale HAP on the crystal phase, microstructure and compressive strength of GBNHAPC were studied respectively. It was concluded that nanoscale HAP could inhibit the cell proliferation, while micron HAP could not, and that nanoscale HAP could be dispersed in the cement evenly and the morphology did not change significantly after a longer immersion time. XRD and FTIR results show nanoscale HAP did not affect the setting reaction of the cement. Furthermore, GBNHAPC had a higher compressive strength (92 MPa) than GBC. It was believed that GBNHAPC might be a desirable biomaterial that could not only fill bone defects but also inhibit cancer cell growth.

  18. Influence of Superplasticizer-Microsilica Complex on Cement Hydration, Structure and Properties of Cement Stone

    Science.gov (United States)

    Ivanov, I. M.; Kramar, L. Ya; Orlov, A. A.

    2017-11-01

    According to the study results, the influence of complex additives based on microsilica and superplasticizers on the processes of the heat release, hydration, hardening, formation of the structure and properties of cement stone was determined. Calorimetry, derivatography, X-ray phase analysis, electronic microscopy and physical-mechanical methods for analyzing the properties of cement stone were used for the studies. It was established that plasticizing additives, in addition to the main water-reducing and rheological functions, regulate cement solidification and hardening while polycarboxylate superplasticizers even contribute to the formation of a special, amorphized microstructure of cement stone. In a complex containing microsilica and a polycarboxylate superplasticizer the strength increases sharply with a sharp drop in the capillary porosity responsible for the density, permeability, durability, and hence, the longevity of concrete. All this is a weighty argument in favor of the use of microsilica jointly with a polycarboxylate superplasticizer in road concretes operated under aggressive conditions.

  19. Retention and marginal leakage of provisional crowns cemented with provisional cements enriched with chlorhexidine diacetate.

    Science.gov (United States)

    Lewinstein, Israel; Chweidan, Harry; Matalon, Shlomo; Pilo, Raphael

    2007-11-01

    Provisional crowns cemented with provisional luting agents are susceptible to washout, marginal leakage, and secondary caries when placed for a prolonged period. The purpose of this study was to examine the effect of incorporating chlorhexidine diacetate (antibacterial agent) into provisional cements on retention and marginal leakage of provisional crowns in vitro. Provisional crowns of acrylic resin (Duralay) were fabricated for 12 intact human molars with rounded-shoulder preparations. The 12 provisional crowns were luted individually with Temp Bond, Temp Bond NE, and Freegenol provisional cements with and without incorporation of chlorhexidine diacetate (CHDA) salt. Each test group included the same 12 specimens. Specimens with no luting agent served as the control (n=12). Specimens were thermal cycled 100 times (5 degrees C and 55 degrees C) with a 10-second dwell time, stored in 100% humidity at 37 degrees C for 6 days, and then immersed in a 0.5% basic fuchsin at 37 degrees C for 6 hours. Seven days after cementation, removal test of the crowns (tensile retention test) was conducted with a universal testing machine at a crosshead speed of 5 mm/min. Marginal leakage was assessed with a 5-level dye penetration scale. Results of the retention test were subjected to a 2-way ANOVA with repeated measures. A Bonferroni test was used to compare the means. Marginal leakage data were subjected to a nonparametric Wilcoxon signed ranks test. All hypothesis testing was conducted at the 95% level of confidence. Retention of provisional crowns cemented with Freegenol enriched with CHDA increased 3-fold to an average level of 80.9 N. However, incorporation of CHDA into Temp Bond or Temp Bond NE did not affect retention. CHDA incorporated into the cements had no significant effect on the marginal leakage of all the tested cements. The addition of CHDA increased retention of Freegenol and had no significant effect on the marginal leakage of the tested cements.

  20. Comparison of modified sulfur cement and hydraulic cement for encapsulation of radioactive and mixed wastes

    International Nuclear Information System (INIS)

    Kalb, P.D.; Heiser, J.H. III; Colombo, P.

    1990-01-01

    The majority of solidification/stabilization systems for low-level radioactive waste (LLW) and mixed waste, both in the commercial sector and at Department of Energy (DOE) facilities, utilize hydraulic cement (such as portland cement) to encapsulate waste materials and yield a monolithic solid waste form for disposal. A new and innovative process utilizing modified sulfur cement developed by the US Bureau of Mines has been applied at Brookhaven National Laboratory (BNL) for the encapsulation of many of these ''problem'' wastes. Modified sulfur cement is a thermoplastic material, and as such, it can be heated above it's melting point (120 degree C), combined with dry waste products to form a homogeneous mixture, and cooled to form a monolithic solid product. Under sponsorship of the DOE, research and development efforts at BNL have successfully applied the modified sulfur cement process for treatment of a range of LLWs including sodium sulfate salts, boric acid salts, and incinerator bottom ash and for mixed waste contaminated incinerator fly ash. Process development studies were conducted to determine optimal waste loadings for each waste type. Property evaluation studies were conducted to test waste form behavior under disposal conditions by applying relevant performance testing criteria established by the Nuclear Regulatory Commission (for LLW) and the Environmental Protection Agency (for hazardous wastes). Based on both processing and performance considerations, significantly greater waste loadings were achieved using modified sulfur cement when compared with hydraulic cement. Technology demonstration of the modified sulfur cement encapsulation system using production-scale equipment is scheduled for FY 1991. 12 refs., 8 figs., 3 tabs

  1. Influence of microwave irradiation of cement mixtures on the strength of cement stone and concrete

    Science.gov (United States)

    Dmitriev, M. S.; Dyakonov, M. V.; Krasnokutskiy, R. A.; Kolyaskin, A. D.; Dmitriev, S. A.

    2017-12-01

    The influence of microwave irradiation of mixtures on the strength of cement stone and concrete was studied. Created at NRNU MEPHI experimental installation for the investigation of microwave effects on imperfect dielectrics and semiconductor materials was the source of radiation. It is shown that on the twenty-eighth day after mixing, the strength of the cement stone increases by 1.2 times, and that of concrete by 2.2 times.

  2. A Study on Provisional Cements, Cementation Techniques, and Their Effects on Bonding of Porcelain Laminate Veneers

    OpenAIRE

    Vinod Kumar, G.; Soorya Poduval, T.; Bipin Reddy; Shesha Reddy, P.

    2013-01-01

    Minimal tooth preparation is required for porcelain laminate veneers, but interim restorations are a must to protect their teeth against thermal insult, chemical irritation, and to provide aesthetics. Cement remaining after the removal of the provisional restoration can impair the etching quality of the tooth surface and fit and final bonding of the porcelain laminate veneer. This in vitro study examined the tooth surface for remaining debris of cement after removal of a provisional restorati...

  3. The Comparative Approach to the Survey of Western Civilization

    Science.gov (United States)

    Winkler, Fred H.

    1972-01-01

    Through the comparative approach to teaching Western Civilization, the student is confronted by a discussion of some aspect of several civilizations or countries within the same time period instead of a civilization-by-civilization or a country-by-country analysis. (Author/JB)

  4. Calcium phosphate cement scaffolds with PLGA fibers.

    Science.gov (United States)

    Vasconcellos, Letícia Araújo; dos Santos, Luís Alberto

    2013-04-01

    The use of calcium phosphate-based biomaterials has revolutionized current orthopedics and dentistry in repairing damaged parts of the skeletal system. Among those biomaterials, the cement made of hydraulic grip calcium phosphate has attracted great interest due to its biocompatibility and hardening "in situ". However, these cements have low mechanical strength compared with the bones of the human body. In the present work, we have studied the attainment of calcium phosphate cement powders and their addition to poly (co-glycolide) (PLGA) fibers to increase mechanical properties of those cements. We have used a new method that obtains fibers by dripping different reagents. PLGA fibers were frozen after lyophilized. With this new method, which was patented, it was possible to obtain fibers and reinforcing matrix which furthered the increase of mechanical properties, thus allowing the attainment of more resistant materials. The obtained materials were used in the construction of composites and scaffolds for tissue growth, keeping a higher mechanical integrity. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Peat Soil Stabilization using Lime and Cement

    Science.gov (United States)

    Zambri, Nadhirah Mohd; Ghazaly, Zuhayr Md.

    2018-03-01

    This paper presents a study of the comparison between two additive Lime and Cement for treating peat soil in term of stabilization. Peat and organic soils are commonly known for their high compressibility, extremely soft, and low strength. The aim of this paper is to determine the drained shear strength of treated peat soil from Perlis for comparison purposes. Direct Shear Box Test was conducted to obtain the shear strength for all the disturbed peat soil samples. The quick lime and cement was mixed with peat soil in proportions of 10% and 20% of the dry weight peat soil. The experiment results showed that the addition of additives had improved the strength characteristics of peat soil by 14% increment in shear strength. In addition, the mixture of lime with peat soil yield higher result in shear strength compared to cement by 14.07% and 13.5% respectively. These findings indicate that the lime and cement is a good stabilizer for peat soil, which often experienced high amount of moisture content.

  6. Topics in cement and concrete research

    NARCIS (Netherlands)

    Brouwers, Jos; Russel, M.I.; Basheer, P.A.M.

    2007-01-01

    The present paper addresses several topics in regard to the sustainable design and use of concrete. First, major features concerning the sustainable aspects of the material concrete are summarised. Then the major constituent, from an environmental point of view, cement is discussed in detail,

  7. Marginal adaptation of ceramic inserts after cementation

    NARCIS (Netherlands)

    Ozcan, M; Pfeiffer, P; Nergiz, [No Value

    2002-01-01

    The advantage of using ceramic inserts is to prevent major drawbacks of composite resins such as polymerization shrinkage, wear and microleakage. This in vitro study evaluated the marginal adaptation of two approximal ceramic insert systems after cementation to the cavities opened with ultrasonic

  8. PROPERTIES OF CEMENT PASTE AND CONCRETE CONTAINING ...

    African Journals Online (AJOL)

    This paper assessed the effect of calcium carbide waste (CCW) as additive on the properties of cement paste and concrete. The CCW used was sourced from a local panel beating workshop. It was sundried and sieved through a 75 µm sieve and characterized by X-Ray Fluorescence (XRF) analytical method.

  9. Percutaneous cement augmentation for osteoporotic vertebral fractures.

    Science.gov (United States)

    Sebaaly, Amer; Rizkallah, Maroun; Bachour, Falah; Atallah, Firas; Moreau, Pierre Emmanuel; Maalouf, Ghassan

    2017-06-01

    Thoracolumbar vertebral fracture incidents usually occur secondary to a high velocity trauma in young patients and to minor trauma or spontaneously in older people.Osteoporotic vertebral fractures are the most common osteoporotic fractures and affect one-fifth of the osteoporotic population.Percutaneous fixation by 'vertebroplasty' is a tempting alternative for open surgical management of these fractures.Despite discouraging initial results of early trials for vertebroplasty, cement augmentation proved its superiority for the treatment of symptomatic osteoporotic vertebral fracture when compared with optimal medical treatment.Early intervention is also gaining ground recently.Kyphoplasty has the advantage over vertebroplasty of reducing kyphosis and cement leak.Stentoplasty, a new variant of cement augmentation, is also showing promising outcomes.In this review, we describe the additional techniques of cement augmentation, stressing the important aspects for success, and recommend a thorough evaluation of thoracolumbar fractures in osteoporotic patients to select eligible patients that will benefit the most from percutaneous augmentation. A detailed treatment algorithm is then proposed. Cite this article: EFORT Open Rev 2017;2:293-299. DOI: 10.1302/2058-5241.2.160057.

  10. The case of Mugher cement facto

    African Journals Online (AJOL)

    Thomas

    through co-generation of carbonate/bicarbonate: The case of Mugher cement factory. Getachew Dagnew Gebreeyessus1*, Tassisa Kaba2 and Bhagwan Singh Chandravanshi3. 1Department of Environmental Health Sciences, Haramaya University, P.O. Box 235, Harar, Ethiopia. 2School of Chemical and Bio-Engineering, ...

  11. Portland cement concrete air content study.

    Science.gov (United States)

    1987-04-20

    This study took the analysis of Portland cement concrete air content. Based on the information gathered, this study hold the results were : 1) air-entrained concrete was more durable than non-air entrained concrete all other factors being equal; 2) A...

  12. Application of Carbonate Looping to Cement Industry

    DEFF Research Database (Denmark)

    Lin, Weigang; Illerup, Jytte Boll; Dam-Johansen, Kim

    2012-01-01

    In the present work, cycle experiments of different types of limestone, cement raw meal and a mixture of limestone and clay were carried out in laboratory scale setups at more realistic conditions (i.e. calcination temperature is 950°C and CO2 concentration is 80%) to simulate the performance of ...

  13. Alkali binding in hydrated Portland cement paste

    NARCIS (Netherlands)

    Chen, Wei; Brouwers, Jos

    2010-01-01

    The alkali-binding capacity of C–S–H in hydrated Portland cement pastes is addressed in this study. The amount of bound alkalis in C–S–H is computed based on the alkali partition theories firstly proposed by Taylor (1987) and later further developed by Brouwers and Van Eijk (2003). Experimental data

  14. The Effect of Temporary Cement Cleaning Methods on the Retention of Crowns.

    Science.gov (United States)

    Song, Mi-Young; An, Hongseok; Park, Eun-Jin

    2017-06-09

    To evaluate the effect of temporary cement cleaning methods on the retention of cemented crowns using zinc phosphate cement and resin-modified glass ionomer cement. Forty titanium specimens were fabricated to simulate prepared molars with minimally retentive taper. The Ni-Cr cast crowns were fabricated, temporarily cemented, and separated. The specimens were divided into four groups according to the temporary cement cleaning method (n = 10) as follows: control group (no temporary cementation), orange solvent group, ultrasonic cleaning group, and air-abrasion group. After the cleaning procedures, the specimens were cemented with definitive cements (zinc phosphate cement and resin-modified glass ionomer, RMGI, cement) and subjected to thermocycling (5000 cycles, 5-55°C, dwell time, 10 seconds). The tensile bond strength of each specimen was measured using a universal testing machine, and the results were analyzed using the Kruskal-Wallis and Mann-Whitney U test (α = 0.05). When cemented with zinc phosphate cement, the statistical analysis showed that the value of the air-abrasion group was significantly higher than those of the other groups (p crowns when zinc phosphate cement was used for permanent cementation. Airborne-particle abrasion after provisional cementation improved retention of crowns cemented with zinc phosphate cement; however, the use of temporary cement significantly decreased retention of permanently cemented crowns when RMGI cement was used regardless of the temporary cement cleaning method. © 2017 by the American College of Prosthodontists.

  15. Effect of dentin sealers on postoperative sensitivity of complete cast crowns cemented with glass ionomer cement.

    Science.gov (United States)

    Maghrabi, Abdulhamaid A

    2011-07-01

    The purpose of this study was to clinically evaluate the effects of pretreatments with copal/ether varnish and dentin bonding system on postoperative sensitivity of complete cast crowns cemented with glass ionomer cement. Three posterior teeth with no pain symptoms were selected from each of 17 patients, totaling 51 teeth, for which a crown was indicated. Rexillium III complete cast crowns were prepared using conventional laboratory techniques. For each patient, the first tooth, which served as the control, received only glass ionomer cement (Ketac-Cem). Copal/ether varnish (Bosworth Copaliner) was applied to the second tooth preparation prior to cementation. Dentin bonding agent (OptiBond Solo Plus) was used on the third tooth before cementation. Sensitivity to different stimuli (cold, heat) was assessed at 7 days, 1 month, and 6 months following restorative procedures by questionnaire. There were no statistically significant differences between the three groups regarding applied stimulus and day of the study (p > 0.05). No statistically significant differences were found between the postoperative sensitivity responses from 7 days to 1 month, and from 1 month to 6 months (p > 0.05). Postoperative sensitivity resulting from glass ionomer cement with complete cast crowns cannot be completely eliminated with the prior use of a cavity varnish or bonding agent. © 2011 by the American College of Prosthodontists.

  16. Absorption Characteristics of Cement Combination Concrete Containing Portland Cement, fly ash, and Metakaolin

    Directory of Open Access Journals (Sweden)

    Folagbade S.O.

    2016-03-01

    Full Text Available The resistance to water penetration of cement combination concretes containing Portland cement (PC, fly ash (FA, and metakaolin (MK have been investigated at different water/cement (w/c ratios, 28-day strengths, and depths of water penetration using their material costs and embodied carbon-dioxide (eCO2 contents. Results revealed that, at equal w/c ratio, eCO2 content reduced with increasing content of FA and MK. MK contributed to the 28-day strengths more than FA. Compared with PC, FA reduced cost and increased the depth of water penetration, MK increased cost and reduced the depth of water penetration, and their ternary combinations become beneficial. At equal strengths and levels of resistance to water penetration, most of the cement combination concretes are more environmentally compatible and costlier than PC concrete. Only MK binary cement concretes with 10%MK content or more and ternary cement concretes at a total replacement level of 55% with 10%MK content or more have higher resistance to water penetration than PC concrete.

  17. Portland cement hydration and early setting of cement stone intended for efficient paving materials

    Science.gov (United States)

    Grishina, A.

    2017-10-01

    Due to the growth of load on automotive roads, modern transportation engineering is in need of efficient paving materials. Runways and most advanced highways require Portland cement concretes. This makes important the studies directed to improvement of binders for such concretes. In the present work some peculiarities of the process of Portland cement hydration and early setting of cement stone with barium hydrosilicate sol were examined. It was found that the admixture of said sol leads to a shift in the induction period to later times without significant change in its duration. The admixture of a modifier with nanoscale barium hydrosilicates increases the degree of hydration of the cement clinker minerals and changes the phase composition of the hydration products; in particular, the content of portlandite and tricalcium silicate decreases, while the amount of ettringite increases. Changes in the hydration processes of Portland cement and early setting of cement stone that are caused by the nanoscale barium hydrosilicates, allow to forecast positive technological effects both at the stage of manufacturing and at the stage of operation. In particular, the formwork age can be reduced, turnover of molds can be increased, formation of secondary ettringite and corrosion of the first type can be eliminated.

  18. Post-cementation colorimetric evaluation of the interaction between the thickness of ceramic veneers and the shade of resin cement.

    Science.gov (United States)

    Calgaro, Patricia Angélica Milani; Furuse, Adilson Yoshio; Correr, Gisele Maria; Ornaghi, Bárbara Pick; Gonzaga, Carla Castiglia

    2014-08-01

    To evaluate the color parameters (CIELab*) after the cementation of ceramic disks of different thicknesses onto a resin substrate using four different shades of resin cements, and determine the color difference (ΔE) between the adhesively cemented disks and a 10 mm-thick A1 shade ceramic control (target color). Ceramic disks, simulating laminate veneers, with thicknesses of 0.5, 0.7 and 1.0 mm (shade A1, IPS Classic) were fabricated (n = 40) and cemented with a dual-cured resin cement (Variolink II, shades A1, bleach, opaque and transparent) onto 120 2 mm-thick resin composite substrates (shade A3.5, Adoro). Each ceramic disk was photocured for 80 seconds. The determination of the CIELab* parameters of each ceramic-cement-substrate set was performed with a spectrophotometer. A 10 mm-thick A1 ceramic disk was used as a control. The results for the color difference (ΔE) obtained from L*, a* and b* parameters were analyzed using ANOVA and Tukey's test (α = 0.05). The ΔE values ranged from 2.46 (1.0 mm, opaque cement) to 12.11 (0.5 mm, A1 cement). The opaque cement showed the lower ΔE values, followed by the bleach, transparent and A1 cements. With respect to the thickness of the ceramic, color differences between the target color and the group with 1.0 mm ceramic disks were smaller for all cement shades tested. Only the combination of 1.0 mm ceramic disks cemented with the opaque cement was able to mask the background color (ΔE resin cement were smaller in comparison with the bleach, transparent and A1 cements.

  19. Influence of the mineralogical composition of cement in the diffusion of chemical species

    International Nuclear Information System (INIS)

    Galicia A, E.

    2015-01-01

    The disposal is the final stage of radioactive waste management. This is essentially placing them in a facility with a reasonable assurance of safety. In this last stage, the ultimate goal is the confinement and isolation of radioactive waste from the human environment for a time period and under conditions such that the release of radionuclides not put in radiation risk to people and the environment. In relation to the storage of radioactive waste of low and medium activity, the final repositories for radioactive waste, based in cement materials are already operating in many countries. The isolation is performed by applying natural or artificial barriers between radioactive waste and man so as to prevent the release of radionuclides to the environment, until they have decreased their toxicity. The cement-based materials are involved in the different stages of the radioactive waste management since they are used for immobilization of waste in the container, container manufacturing and filling the spaces between the containers and vaults container and also as a barrier engineering and construction material in civil engineering. The concrete (cement mix + water + sand + gravel) it is one of the materials used to produce the engineered barrier system and produce containers for radioactive waste. In addition to their mechanical properties (product processing into hydraulic binder after being hydrated), their composition and solubility allow cushion the contact groundwater to ph higher (12.0 - 13.5) during considerable time scales (10 14 - 10 15 years) and it has an active role with the radionuclides confinement present in the radiological inventory of radioactive waste. The study of the microstructures of cement is a constant challenge for specialists working in this area, mainly due to the complex and heterogeneous mineralogical composition. Cement consists of many different phases in order to achieve specific properties such as reactivity properties, setting time

  20. Densified ultra-light cement-based materials

    DEFF Research Database (Denmark)

    Esteves, Luis Pedro

    2015-01-01

    Densified cement systems were developed in the early 1980s, about three decades past. The research led to historical developments in cement and concrete research, forming the baseline for the design of modern cement systems, the socalled high-performance and ultra-high performance concrete. Cement...... production comprehends one of the relevant carbon emission footprints in the world. The substitution of cement by supplementary cementitious additions encompasses several other health hazards, risks and also technical difficulties such as limited or incoherent pozzolanic activity. Superabsorbent polymers can...... be used as a “clean technology” in the production of cement-based materials for structural applications with a low carbon footprint. This paper describes the principles of this concept coupled with experimental results on the basic properties of this enhanced type of cement-based materials with combined...

  1. Cementation and solidification of Rocky Flats Plant incinerator ash

    International Nuclear Information System (INIS)

    Phillips, J.A.; Semones, G.B.

    1994-01-01

    Cementation studies on various aqueous waste streams at Rocky Flats have shown this technology to be effective for immobilizing the RCRA constituents in the waste. Cementation is also being evaluated for encapsulation of incinerator ash. Experiments will initially evaluate a surrogate ash waste using a Taguchi experimental design to optimize the cement formulation and waste loading levels for this application. Variables of waste loading, fly ash additions, water/cement ratio, and cement type will be tested at three levels each during the course of this work. Tests will finally be conducted on actual waste using the optimized cement formulation developed from this testing. This progression of tests will evaluate the effectiveness of cement encapsulation for this waste stream without generating any additional wastes

  2. Mechanical Properties and Decay Resistance of Hornbeam Cement Bonded Particleboards

    Directory of Open Access Journals (Sweden)

    Antonios N. Papadopoulos

    2008-01-01

    Full Text Available Cement bonded particleboards were manufactured from hornbeam (Carpinus betulus L. wood particles. Hydration tests were carried out to determine the inhibitory index in order to characterise wood-cement compatibility. The results revealed that the mixture of hornbeam-cement can be classified as moderate inhibition. Two wood: cement ratios were applied in this study, namely, 1 : 3 and 1 : 4, for the board manufacture. It was found that an increase of cement-wood ratio resulted in an improvement in all properties examined, except MOR. All properties of the boards made from 1 : 4 wood: cement ratio surpassed the minimum requirements set forth by the building type HZ code. Boards were exposed to brown and white rot fungi, Coniophora puteana, and Trametes versicolor, respectively. Overall, both fungi failed to attack the cement-bonded boards.

  3. Assessment of cement durability in repository environment

    International Nuclear Information System (INIS)

    Ferreira, E.G.A.; Vicente, R.; Isiko, V.L.K.; Miyamoto, H.; Marumo, J.T.; Gobbo, L.A.

    2015-01-01

    The present research aimed at investigating the durability of cement paste under nuclear waste repository conditions using accelerated tests. Cement paste samples are examined after being exposed to the environmental conditions that are expected to prevail in the repository environment and the results are compared with those obtained with unexposed specimens or specimens exposed to reference conditions. The following exposure conditions were selected: a) Immersion in salt solution, distilled water, or kept in dry storage; b) Room temperature (20 C. degrees) or high temperature (60 C. degrees); c) Immersion time of 30 days or 60 days (not for dry storage); d) Irradiation to a dose of (400 kGy) or background radiation (0 kGy). After exposure to the stressing conditions, the effects of each factor on the cement paste samples were observed by changes in their characteristics. Compressive strength tests were performed on all samples and some of them were investigated in terms of changes in mineralogy by X-ray diffraction (XRD) and thermo-gravimetric analysis (TGA). With the results obtained so far it was possible to point out the following conclusions. First, after a period of immersion in water, cement paste samples further hydrated and presented higher mechanical resistance, as expected. Secondly, dry storage did not allow a complete hydration as a consequence of pore water evaporation. High temperatures intensified this process and led to the ettringite decomposition to meta-ettringite. Thirdly, higher temperature accelerated hydration kinetics and promoted higher mechanical resistance in samples kept under immersion. Fourthly, the irradiation dose applied was unable to change the mineralogy of cement paste samples and fifthly, no statistically significant differences were observed between 30 or 60 days exposure time, for the test conditions

  4. Cementation of Nuclear Graphite Using Geopolymers

    International Nuclear Information System (INIS)

    Girke, N.A.; Steinmetz, H-J.; Bukaemsky, A.; Bosbach, D.; Hermann, E.; Griebel, I.

    2016-01-01

    Geopolymers are solid aluminosilicate materials usually formed by alkali hydroxide or alkali silicate activation of solid precursors such as coal fly ash, calcined clay and/or metallurgical slag. Today the primary application of geopolymer technology is in the development of alternatives to Portland-based cements. Variations in the ratio of aluminium to silicon, and alkali to silicon or addition of structure support, produce geopolymers with different physical and mechanical properties. These materials have an amorphous three-dimensional structure that gives geopolymers certain properties, such as fire and acid resistance, low leach rate, which make them an ideal substitute for ordinary Portland cement (OPC) in a wide range of applications especially in conditioning and storage of radioactive waste. Therefore investigations have been initiated on how and to which amount graphite as a hydrophobic material can be mixed with cement or concrete to form stable waste products and which concretes fulfil the necessary specifications best. As a result, geopolymers have been identified as a promising matrix for graphite containing nuclear wastes. With geopolymers, both favourable properties in the cementation process and a high long time structural stability of the products can be achieved. Investigations include: • direct mixing of graphite with geopolymers with or without sand as a mechanically stabilizing medium; • production of cement-graphite granulates as intermediate products and embedding of these granulates in geopolymer; • coating of formed graphite pieces with geopolymer.The report shows that carbon in the form of graphite can both be integrated with different grain size spectra as well as shaped in the hydraulic binder geopolymer and meets the requirements for a stable long-term immobilisation. (author)

  5. Solid recovered fuels in the cement industry with special respect to hazardous waste.

    Science.gov (United States)

    Thomanetz, Erwin

    2012-04-01

    Cements with good technical properties have been produced in Europe since the nineteenth century and are now worldwide standardized high-quality mass products with enormous production numbers. The basic component for cement is the so-called clinker which is produced mainly from raw meal (limestone plus clay plus sands) in a rotary kiln with preheater and progressively with integrated calciner, at temperatures up to 1450 °C. This process requires large amounts of fossil fuels and is CO₂-intensive. But most CO₂ is released by lime decomposition during the burning process. In the 1980s the use of alternative fuels began--firstly in the form of used oil and waste tyres and then increasingly by pre-conditioned materials from commercial waste and from high calorific industrial waste (i.e. solid recovered fuel (SRF))--as well as organic hazardous waste materials such as solvents, pre-conditioned with sawdust. Therefore the cement industry is more and more a competitor in the waste-to-energy market--be it for municipal waste or for hazardous waste, especially concerning waste incineration, but also for other co-incineration plants. There are still no binding EU rules identifying which types of SRF or hazardous waste could be incinerated in cement kilns, but there are some well-made country-specific 'positive lists', for example in Switzerland and Austria. Thus, for proper planning in the cement industry as well as in the waste management field, waste disposal routes should be considered properly, in order to avoid surplus capacities on one side and shortage on the other.

  6. Retardation effect of different alcohols on the cement coagulation in polycarboxylate- and naphthalene-based cement admixtures

    Science.gov (United States)

    Huang, S. M.; Zhou, F. L.

    2017-12-01

    Alcohol has great potential to delay the coagulation of cement. The effects of alcohol on paste fluidity and normal consistency coagulation time have been studied for polycarboxylate superplasticizer and naphthene cement admixture. Seven alcohols were combined with polycarboxylate superplasticizer and naphthene at a concentration of 0.01-0.09%, respectively, including n-propanol, methanol, sorbitol, ethylene glycol, glycerol, ethanol, and mannitol. The fluidity and normal consistency coagulation time of each cement admixture were measured. The performance of both polycarboxylate superplasticizer and naphthene cement admixtures were compared to develop cement admixture with delayed coagulation.

  7. TRANSITION COUNTRIES TOWARDS INTERNATIONAL COMPETITIVENESS

    Directory of Open Access Journals (Sweden)

    Gazmend Qorraj

    2013-12-01

    Full Text Available Most of the transition countries in Europe had significant benefits from the EU enlargement but the positive effects depend also from the structure of the economy and reforms of these countries. It’s important to analyze: if transition countries ensured sustainable economic reforms or just short term stability and emergent solutions. This paper will address international competitiveness which is the main challenge for the transition countries but also for the EU. First, monopoly position of some international firms in local markets and lack of creativity and innovations of the local firms, especially in Western Balkans due to lack of institutional support and non-stable business environment. The problem of creativity and lack of innovations by the firms is also a serious issue for the EU countries. The second important issue is large productivity gap. The recent global financial crisis as well as EU crises present the difficulties in the Euro zone and highlighted the interdependence of national economies and the convergence problems within European Union. The third challenge is absorption capacity for the structural and cohesion funds. The past experience of Central European countries shows that success in effectively using the EU financial and technical assistance is positively related with the success of countries on creating sustainable economic development and international competitiveness. Fourth issue is that some transition countries achieved economic growth but due to unequal distribution of welfare on these countries there is no significant reduce of unemployment and social cohesion. Last but not least the international competitiveness in most of the countries is harmed by the lack of functional institutions due to high level of corruption, inefficiency, rule of law, the lack of transparency and accountability.

  8. Simplified cementation of lithium disilicate crowns: Retention with various adhesive resin cement combinations.

    Science.gov (United States)

    Johnson, Glen H; Lepe, Xavier; Patterson, Amanda; Schäfer, Oliver

    2017-09-27

    A composite resin cement and matching self-etch adhesive was developed to simplify the dependable retention of lithium disilicate crowns. The efficacy of this new system is unknown. The purpose of this in vitro study was to determine whether lithium disilicate crowns cemented with a new composite resin and adhesive system and 2 other popular systems provide clinically acceptable crown retention after long-term aging with monthly thermocycling. Extracted human molars were prepared with a flat occlusal surface, 20-degree convergence, and 4 mm axial length. The axio-occlusal line angle was slightly rounded. The preparation surface area was determined by optical scanning and the analysis of the standard tessellation language (STL) files. The specimens were distributed into 3 cement groups (n=12) to obtain equal mean surface areas. Lithium disilicate crowns (IPS e.max Press) were fabricated for each preparation, etched with 9.5% hydrofluoric acid for 15 seconds, and cleaned. Cement systems were RelyX Ultimate with Scotch Bond Universal (3M Dental Products); Monobond S, Multilink Automix with Multilink Primer A and B (Ivoclar Vivadent AG); and NX3 Nexus with OptiBond XTR (Kerr Corp). Each adhesive provided self-etching of the dentin. Before cementation, the prepared specimens were stored in 35°C water. A force of 196 N was used to cement the crowns, and the specimens were polymerized in a 35°C oven at 100% humidity. After 24 hours of storage at 100% humidity, the cemented crowns were thermocycled (5°C to 55°C) for 5000 cycles each month for 6 months. The crowns were removed axially at 0.5 mm/min. The removal force was recorded and the dislodgement stress calculated using the preparation surface area. The type of cement failure was recorded, and the data were analyzed by 1-way ANOVA and the chi-square test (α=.05) after the equality of variances had been assessed with the Levene test. The Levene test was nonsignificant (P=.936). The ANOVA revealed the mean removal

  9. Effect of interim cement application on bond strength between resin cements and dentin: Immediate and delayed dentin sealing.

    Science.gov (United States)

    Brigagão, Vinícius C; Barreto, Luis F D; Gonçalves, Kellem A S; Amaral, Marina; Vitti, Rafael P; Neves, Ana C C; Silva-Concílio, Laís R

    2017-06-01

    Despite the advances in materials and techniques, adhesion to dentin is challenging because of the complex composition of dentin's mineral, organic, and fluid phases. The purpose of this in vitro study was to evaluate the bond strength of 2 different resin cements (conventional and self-adhesive) with or without previous dentin sealing and the effect of interim cement. Forty-five molars were embedded into acrylic resin blocks and a flat dentin surface was exposed. Twenty teeth (n=5 per group) were treated with the conventional resin cement associated with etch-and-rinse or self-etch adhesive approaches, applied before (immediate dentin sealing) or after (delayed dentin sealing) the application/removal of interim cement. Another 25 teeth (n=5, per group) were treated with self-adhesive resin cement with (self-etch mode [immediate dentin sealing or delayed dentin sealing]) or without adhesive application. Furthermore, in the self-adhesive resin cement group, the application of polyacrylic acid for dentin etching before cementation was evaluated. Composite resin blocks were cemented onto flat, treated dentin surfaces, and the assemblies were sectioned into bar-shaped specimens for microtensile bond strength testing. The data were subjected to 1-way ANOVA followed by the post-hoc Tukey test (α=.05). The failure patterns were classified as cohesive, adhesive, or mixed. The application of adhesive before interim cement (immediate dental sealing) promoted the highest values of bond strength for both resin cements (Presin cement, polyacrylic acid-enhanced bond strength after the application of interim cement. The application of dental adhesive immediately after tooth preparation (immediate dentin sealing) and before the use of an interim cement promoted the highest values of bond strength to dentin with the resin cements tested. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  10. Push-out bond strengths of different dental cements used to cement glass fiber posts.

    Science.gov (United States)

    Pereira, Jefferson Ricardo; Lins do Valle, Accácio; Ghizoni, Janaina Salomon; Lorenzoni, Fábio César; Ramos, Marcelo Barbosa; Barbosa, Marcelo Ramos; Dos Reis Só, Marcus Vinícius

    2013-08-01

    Since the introduction of glass fiber posts, irreversible vertical root fractures have become a rare occurrence; however, adhesive failure has become the primary failure mode. The purpose of this study was to evaluate the push-out bond strength of glass fiber posts cemented with different luting agents on 3 segments of the root. Eighty human maxillary canines with similar root lengths were randomly divided into 8 groups (n=10) according to the cement assessed (Rely X luting, Luting and Lining, Ketac Cem, Rely X ARC, Biscem, Duo-link, Rely X U100, and Variolink II). After standardized post space preparation, the root dentin was pretreated for dual-polymerizing resin cements and untreated for the other cements. The mixed luting cement paste was inserted into post spaces with a spiral file and applied to the post surface that was seated into the canal. After 7 days, the teeth were sectioned perpendicular to their long axis into 1-mm-thick sections. The push-out test was performed at a speed of 0.5 mm/min until extrusion of the post occurred. The results were evaluated by 2-way ANOVA and the all pairwise multiple comparison procedures (Tukey test) (α=.05). ANOVA showed that the type of interaction between cement and root location significantly influenced the push-out strength (Plower bond strength. Significant differences among root segments were found only for Duo-link cement. Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  11. OPPORTUNITIES TO MARKET U.S. TECHNOLOGIES THROUGHOUT THE WESTERN HEMISPHERE

    Energy Technology Data Exchange (ETDEWEB)

    M.A. Ebadian, Ph.D

    1999-01-01

    This project involves an open-ended, continuous process of information gathering with respect to Latin American and Caribbean environmental issues. This entails the development of contacts with individuals and institutions conducting research and work on issues of sustainability and environmental technology in the Americas. As part of this phase, a database containing information on firms, nongovernmental organizations (NGOs), governmental institutions, and other participants in Latin America's environmental sector was developed and is continually being updated. In addition, FIU-HCET's efforts were geared toward determining environmental technological needs in different parts of the region and identifying the most significant and lucrative markets. The project requires that FIU-HCET continually cement those contacts already established, continue updating the database to be made available to external users, and identify U.S. companies with the necessary expertise to participate in the Latin American and Caribbean markets. To aid in this endeavor, comprehensive, country-specific studies of the market for environmental goods and services are drafted and published by FIU-HCET. FIU-HCET, with sponsorship from OST, will make new, innovative, and more cost-effective technologies available for transfer throughout the Western Hemisphere. Environmental/energy technology development projects encompass the range of problems experienced by LACN. This includes mixed waste characterization and treatment, soils and groundwater remediation. In addition, future activities will include the issues of energy, climate change, and fossil fuels.

  12. Polyethylene glycol improves elution properties of polymethyl methacrylate bone cements.

    Science.gov (United States)

    Handal, John A; Tiedeken, Nathan C; Gershkovich, Grigory E; Kushner, Jeffrey A; Dratch, Benjamin; Samuel, Solomon P

    2015-03-01

    Bone cements are used as adjuncts to fracture fixation methods and can also function as a local drug delivery system. The ability to elute drugs makes bone cement a promising and powerful chemotherapy treatment modality for osseous tumors. However, because of poor elution rates, the clinical application of this drug delivery mode remains challenging. Soluble fillers, such as sugars, salts, or biocompatible polymers, offer a solution to improve elution rates. This study quantified the effect of polyethylene glycol (PEG) on the elution properties of three commercially available bone cements. Two grams of Vertebroplastic, Palacos, and Confidence bone cement powder containing three concentrations (0%, 20%, or 50%) of PEG filler were hand mixed with 10 mg of methotrexate. This powder mixture was then polymerized with 1.0 mL of the cement specific liquid monomer. The cylindrical elution samples were placed in saline solution and methotrexate elution was recorded for 720 h. The cumulative and daily elution rate increased as the concentration of PEG increased for each bone cement. However, the percent of increase depended on the bone cement used. Cumulative methotrexate elution increased by 40%-54% in case of the highest PEG filler concentration when compared with controls. PEG soluble filler offers a promising method for improving methotrexate drug elution in bone cement. Future studies need to optimize the PEG and bone cement ratio that produces the greatest drug elution profile without sacrificing the biomechanical properties of bone cement. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Microstructure characteristics of cement-stabilized sandy soil using nanosilica

    Directory of Open Access Journals (Sweden)

    Asskar Janalizadeh Choobbasti

    2017-10-01

    Full Text Available An experimental program was conducted to explore the impact of nanosilica on the microstructure and mechanical characteristics of cemented sandy soil. Cement agent included Portland cement type II. Cement content was 6% by weight of the sandy soil. Nanosilica was added in percentages of 0%, 4%, 8% and 12% by weight of cement. Cylindrical samples were prepared with relative density of 80% and optimum water content and cured for 7 d, 28 d and 90 d. Microstructure characteristics of cement-nanosilica-sand mixtures after 90 d of curing have been explored using atomic force microscopy (AFM, scanning electron microscopy (SEM and X-ray diffraction (XRD tests. Effects of curing time on microstructure properties of cemented sandy soil samples with 0% and 8% nanosilica have been investigated using SEM test. Unconfined compression test (for all curing times and compaction test were also performed. The SEM and AFM tests results showed that nanosilica contributes to enhancement of cemented sandy soil through yielding denser, more uniform structure. The XRD test demonstrated that the inclusion of nanosilica in the cemented soil increases the intensity of the calcium silicate hydrate (CSH peak and decreases the intensity of the calcium hydroxide (CH peak. The results showed that adding optimum percentages of nanosilica to cement-stabilized sandy soil enhances its mechanical and microstructure properties.

  14. Effect of cements on fracture resistance of monolithic zirconia crowns

    Science.gov (United States)

    Nakamura, Keisuke; Mouhat, Mathieu; Nergård, John Magnus; Lægreid, Solveig Jenssen; Kanno, Taro; Milleding, Percy; Örtengren, Ulf

    2016-01-01

    Abstract Objectives The present study investigated the effect of cements on fracture resistance of monolithic zirconia crowns in relation to their compressive strength. Materials and methods Four different cements were tested: zinc phosphate cement (ZPC), glass-ionomer cement (GIC), self-adhesive resin-based cement (SRC) and resin-based cement (RC). RC was used in both dual cure mode (RC-D) and chemical cure mode (RC-C). First, the compressive strength of each cement was tested according to a standard (ISO 9917-1:2004). Second, load-to-failure test was performed to analyze the crown fracture resistance. CAD/CAM-produced monolithic zirconia crowns with a minimal thickness of 0.5 mm were prepared and cemented to dies with each cement. The crown–die samples were loaded until fracture. Results The compressive strength of SRC, RC-D and RC-C was significantly higher than those of ZPC and GIC (p crown between the groups. Conclusion The values achieved in the load-to-failure test suggest that monolithic zirconia crowns with a minimal thickness of 0.5 mm may have good resistance against fracture regardless of types of cements. PMID:27335900

  15. Alkali-slag cements for the immobilization of radioactive wastes

    International Nuclear Information System (INIS)

    Shi, C.; Day, R.L.

    1996-01-01

    Alkali-slag cements consist of glassy slag and an alkaline activator and can show both higher early and later strengths than Type III Portland cement, if a proper alkaline activator is used. An examination of microstructure of hardened alkali-slag cement pastes with the help of XRD and SEM with EDAX shows that the main hydration product is C-S-H (B) with low C/S ratio and no crystalline substances exist such as Ca(OH) 2 , Al (OH) 3 and sulphoaluminates. Mercury intrusion tests indicate that hardened alkali-slag cement pastes have a lower porosity than ordinary Portland cement, and contain mainly gel pores. The fine pore structure of hardened alkali-slag cement pastes will restrict the ingress of deleterious substances and the leaching of harmful species such as radionuclides. The leachability of Cs + from hardened alkali-slag cement pastes is only half of that from hardened Portland cement. From all these aspects, it is concluded that alkali-slag cements are a better solidification matrix than Portland cement for radioactive wastes

  16. Pedicle screw augmentation with bone cement enforced Vicryl mesh.

    Science.gov (United States)

    Schmid, Samuel L; Bachmann, Elias; Fischer, Michael; Meyer, Dominik C; Gerber, Christoph A; Snedeker, Jess G; Farshad, Mazda

    2018-01-01

    Achieving sufficient mechanical purchase of pedicle screws in osteoporotic or previously instrumented bone is technically and biologically challenging. Techniques using different kinds of pedicle screws or methods of cement augmentation have been used to address this challenge, but are associated with difficult revisions and complications. The purpose of this biomechanical trial was to investigate the use of biocompatible textile materials in combination with bone cement to augment pullout strength of pedicle screws while reducing the risk of cement extrusion. Pedicle screws (6/40 mm) were either augmented with standard bone-cement (Palacos LV + G) in one group (BC, n = 13) or with bone-cement enforced by Vicryl mesh in another group (BCVM, n = 13) in osteoporosis-like saw bone blocks. Pullout testing was subsequently performed. In a second experimental phase, similar experiments were performed using human cadaveric lumbar vertebrae (n = 10). In osteoporosis-like saw bone blocks, a mean screw pullout force of 350 N (±125) was significantly higher with the Bone cement (BC) compared to bone-cement enforced by Vicryl mesh (BCVM) technique with 240 N (±64) (p = 0.030). In human cadaveric lumbar vertebrae the mean screw pullout force was 784 ± 366 N with BC and not statistically different to BCVM with 757 ± 303 N (p = 0.836). Importantly, cement extrusion was only observed in the BC group (40%) and never with the BCVM technique. In vitro textile reinforcement of bone cement for pedicle screw augmentation successfully reduced cement extrusion compared to conventionally delivered bone cement. The mechanical strength of textile delivered cement constructs was more reproducible than standard cementing. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:212-216, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  17. Nuclear power in western society

    International Nuclear Information System (INIS)

    Franklin, N.L.

    1977-01-01

    The degree to which problems of public acceptance have contributed to the slowdown in progress of nuclear power in Western European countries and the USA is discussed. Some of the effects on the nuclear power industry, i.e. the electrical utilities, the power station suppliers, and the fuel cycle contractors are described. The problem of the lack of public acceptance is examined by consideration of four areas: the position of the employee working in nuclear installations, opposition from the local community, the question of terrorism and its impact on nuclear policy, and finally, what is felt to constitute the greatest anxiety concerning nuclear power, that of proliferation. (U.K.)

  18. Microleakage of porcelain and composite machined crowns cemented with self-adhesive or conventional resin cement.

    Science.gov (United States)

    Ghazy, Mohamed; El-Mowafy, Omar; Roperto, Renato

    2010-10-01

    Resistance of machined crowns to microleakage when cemented with new self-adhesive cements has not been fully investigated. This study evaluated microleakage of machined crowns milled from porcelain and composite blocks and bonded to teeth with self-adhesive and conventional resin cement. Thirty-two freshly extracted premolars of similar shape and size were sterilized and mounted in resin blocks. Teeth received standard crown preparations with 1-mm circumferential shoulder finish line, flat occlusal surface reduced by 2 mm, and ideal angle of convergence. Prepared teeth were divided into two equal groups and assigned to either porcelain (Vita Mark II, Vident) or composite (Paradigm MZ100, 3M ESPE) blocks for crown fabrication. Optical impressions were captured for each tooth with the intraoral camera of a CEREC 3D machine. Crowns were designed and milled from both materials. Each group was then subdivided into two subgroups (n = 8) according to cement used (self-adhesive resin cement, RelyX Unicem, 3M ESPE or resin cement with self-etching adhesive, Panavia F 2.0, Kuraray). Following seating, a 5-kg weight was applied on the occlusal surface of the crown for 5 minutes. Specimens were then stored in water at 37°C for 24 hours. Specimens were thermocycled for 3000 cycles between 5°C and 55°C, then coated with nail varnish and immersed in a 2.0% basic red fuchsine dye solution for 24 hours. Teeth were then rinsed and sectioned mesiodistally and assessed under magnification for microleakage. A five-point scale was used to score degree of microleakage. Data were statistically analyzed with 2-way ANOVA and Kruskal-Wallis nonparametric test. Crown material had no significant effect on microleakage (p= 0.67); however, cement type had a significant effect (p cement, the resin cement with separate primer/bonding agent resulted in significantly lower microleakage scores, irrespective of crown material. © 2010 by The American College of Prosthodontists.

  19. Cement selection for cement-retained crown technique with dental implants.

    Science.gov (United States)

    Sheets, James L; Wilcox, Charles; Wilwerding, Terry

    2008-02-01

    The purpose of this study was to assess and compare the retentive nature of common dental cements that have been adapted for use in the implant abutment cement-retained crown (CRC) technique with those specifically formulated for this purpose. Ten regular diameter implant analogs were embedded in stainless steel disks. Unmodified CRC abutments were attached and torqued to 30 Ncm. Test crowns were waxed and cast with base metal alloy. Castings were fitted, cleaned with aluminum oxide, and steam cleaned prior to application of the cement. The cements used were: (1) Temp Bond, (2) UltraTemp, regular, (3) UltraTemp firm, (4) ImProv with petroleum jelly coating of crown, (5) ImProv without petroleum jelly, (6) Premier Implant with KY Jelly coating of abutment, (7) Premier Implant without KY jelly, (8) TR-2, (9) Fleck's, (10) Ketac Cem Aplicap, and (11) Fuji Plus Capsule. After cementation, assemblies were stored for 24 hours. Each sample was subjected to a pull-out test using an Instron universal testing machine at a crosshead speed of 5.0 mm/min. Loads required to remove the crowns were recorded, and mean values for each group determined. A one-way ANOVA and a post hoc least square difference (LSD) test were done for pairwise comparison at a confidence interval of 95%. The mean values (+/-SD) of loads at failure (n = 10) for various cements were as follows (N): Ultratemp, regular 358.6 (+/-38.2) (Group A), ImProv without petroleum jelly 172.4 (+/-59.6) (Group B), Fleck's 171.8 (+/-62.2) (Group B), Ketac Cem 167.8 (+/-69.1) (Group B), UltraTemp firm 158.8 (+/-62.7) (Group BC), Fuji Plus 147.5 (+/-69.7) (Group BC), Premier without KY jelly 131.6 (+/-31.8) (Group BC), ImProv using petroleum jelly 130.8 (+/-42.5) (Group BC), Temp Bond 117.8 (+/-48.3) (Group C), TR-2 41.2 (+/-16.6) (Group D), and Premier with KY jelly 31.6 (+/-24.8) (Group D). Groups with the same letter were not significantly different. Within the limitations of this in vitro study, it is not suggested

  20. A study on leaching behaviour of cement blocks used as matrix for ...

    Indian Academy of Sciences (India)

    WINTEC

    and b. leaching of Cs activity from cement matrix having ferric, vermiculite and bentonite. 3.3 Optimization of period of curing of cement. In order to confirm the results on the feasibility of forma- tion of cement blocks and also to optimize the curing time to obtain cement blocks of maximum strength, 10 g of. Portland cement ...

  1. 76 FR 28318 - National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing...

    Science.gov (United States)

    2011-05-17

    ... Cement Manufacturing Industry and Standards of Performance for Portland Cement Plants AGENCY... by the Portland Cement Industry and the New Source Performance Standards for Portland Cement Plants... emission limits applicable to the Portland cement industry. See 75 FR 54970 (Sept. 9, 2010). The rule...

  2. Maternal mortality among migrants in Western Europe

    DEFF Research Database (Denmark)

    Pedersen, Grete Skøtt; Grøntved, Anders; Mortensen, Laust Hvas

    2014-01-01

    To examine whether an excess risk of maternal mortality exists among migrant women in Western Europe. We searched electronic databases for studies published 1970 through 2013 for all observational studies comparing maternal mortality between the host country and a defined migrant population...

  3. Microleakage of a self-adhesive resin cement after post cementation.

    Science.gov (United States)

    Camilotti, Veridiana; Consalter, Admilton Fritsche; Dobrovolsk, Max; Bosquirolli, Virginia; Busato, Priscila R D; Mendonça, Marcio J

    2011-01-01

    The aim of this study is to evaluate the microleakage a self-adhesive cement recently marketed Rely X U100 (3M ESPE). Thirty roots of bovine teeth with 14 mm long were restored with self-adhesive cement and Glassix fiber post DC3 (FGM). Roots were randomly divided into three groups (n=10) according to the technique of placement of the cementing agent: G1 - Centrix syringe; G2 - Lentulo drill and G3 - Manual technical. After cementation, provisional restorations were fabricated with composite resin (Opallis/FGM) without the use adhesive system. After they were finished, polished and thermo cycled by 1000 cycles, in water at temperature of 5 degrees C and 55 degrees C, 30 seconds in each bath. For microleakage test each group of roots was immersed in recipients with Rodhamine B dye solution buffered at 2%, during 24 hours. After this time, the samples were washed in tap water, sectioned and evaluation of dye leakage. The values of infiltration were obtained by the qualitative method (scoring) and statistical analysis using Kruskal-Wallis test and also by the quantitative method (Image Tool) and statistical analysis using ANOVA one way. For both tests, no significant difference between the techniques of placement of the self-adhesive cement. Based on these findings, micro-infiltration was present in all groups, and the placement technique did not influence the degree of micro-leakage, both for the qualitative analysis as to the quantitative.

  4. Radiopacity of dental restorative materials and cements

    International Nuclear Information System (INIS)

    Kang, Byung Chul; Yang, Hong So; Chung, Hyun Ju; Oh, Won Mann

    1994-01-01

    The radiopacity of six composite resins, three resin luting cements and ten filling materials were studied. The purpose was to obtain an indication of radiopacity value of different brands within each of these groups of materials and to show differences in radiopacities of filling materials and natural tooth structures. On radiographs, the optimal densities of standardized samples were determined by computer imaging system and radiopacity values of the materials were expressed in millimeter equivalent aluminum. Within to groups of materials studied, there was considerable variation in radiopacity. The composite resins of P-50, Zl00 and prisma AP. H displayed much higher radiopacities than aluminum. Panavia resin cement was shown to be similarly radiopaque to aluminum. Generally, the radiopacity of base and filling materials appeared to combined applications for restorative treatment of teeth, lower radiopacity can interfere with the diagnosis and detection of gaps near the restoration.

  5. Scrap tire ashes in portland cement production

    Directory of Open Access Journals (Sweden)

    Mónica Adriana Trezza

    2009-01-01

    Full Text Available Scrap tires are not considered harmful waste, but their stocking and disposal are a potential health and environmental risk. Properly controlled calcinations at high temperatures make tire combustion an interesting alternative due to its high calorific power, comparable to that of fuel-oil. Consequently, using them as an alternative combustible material in cement kilns makes it possible to give it a valuable use. However, it remains to be assured whether the impurities added to the clinker through these fuels do not affect its structure or properties.This paper shows the studies carried out on different clinkers under laboratory conditions with different levels of addition of scrap tire ashes, added by partially replacing traditional fuel in cement kilns.

  6. DESIGN OF CEMENT COMPOSITES WITH INCREASED IMPERMEABILITY

    Directory of Open Access Journals (Sweden)

    Fedyuk Roman Sergeevich

    2016-05-01

    Full Text Available The paper deals with the development of composite binders for producing concrete with improved characteristics of gas, water and vapor permeability. The authors investigate the processes of composite materials formation in order of decreasing scale levels from macro to nanostructures. The criteria for optimization of the volume of dispersed additives in concrete are offered. The authors theoretically studied the technological features of the formation of hydrated cement stone structure. A positive effect of nanodispersed additives on the structure and physico-mechanical properties of cement composite materials are predicted. Thanks to its improved features, such as good ratio of strength and body density, high density and lifetime, the modified concrete may be used when solving various practical tasks of the construction branch.

  7. Sidoarjo Mud: A Potential Cement Replacement Material

    Directory of Open Access Journals (Sweden)

    Biyanto T.R.

    2010-01-01

    Full Text Available This paper presents an experimental and analytical research conducted to study the properties of mortar when treated Sidoarjo mud was added into the mix replacing partially the cement content. The replacements were done at 0, 5, 10, 15, and 20%. Compression, tensile, porosity and Ultrasonic Pulse Velocity (UPV tests were conducted to evaluate the effect of Sidoarjo mud in mortar. Analyses on the mud were also conducted through X-ray diffraction (XRD, X-ray Fluorescence (XRF, and scanning electron microscope with an energy dispersive X-ray analysis system (SEM-EDX. The results showed that the mud could be used as a cementitious material with optimum ordinary Portland cement (OPC replacement at 10%.

  8. High temperature cement raw meal flowability

    DEFF Research Database (Denmark)

    Maarup, Claus; Hjuler, Klaus; Dam-Johansen, Kim

    2014-01-01

    The flowability of cement raw meal is investigated at temperatures up to 850°C in a specially designed monoaxial shear tester. Consolidation stresses of 0.94, 1.87 and 2.79kPa are applied. The results show that the flowability is reduced as temperature is increased above 550°C, indicated by incre......The flowability of cement raw meal is investigated at temperatures up to 850°C in a specially designed monoaxial shear tester. Consolidation stresses of 0.94, 1.87 and 2.79kPa are applied. The results show that the flowability is reduced as temperature is increased above 550°C, indicated...... by increasing unconfined yield strength and reduced flowability factors. Deviation and reproducibility are acceptable for all temperatures except for 850°C where belite formation and possibly calcination sinter the raw meal....

  9. [Environment load from China's cement production].

    Science.gov (United States)

    Zhu, Tian-le; He, Wei; Zeng, Xiao-lan; Huang, Xin; Ma, Bao-guo

    2006-10-01

    Based on the life-cycle theory, a quantitative evaluation of the environment load caused by cement manufacturing in China was carried out with the application of the CML. environmental impact assessment method. The results show that global warming potential, energy depletion potential and abiotic depletion potential make the main contribution to the environment impact, their environmental loads corresponding to identical environmental impact sorts being 2.76%, 2.34% and 1.39% of the overall load of the whole world, respectively. In 2004, the environment load from cement manufacturing in China is roughly 1.28% of the overall load of the whole world, in which the environmental loads from the shaft kiln processing, wet rotary processing and new-type dry processing being 0.84%, 0.12% and 0.32%, respectively. And it can be reduced to about 1% by replacing backward production processes with the dry method production process.

  10. Stabilization of marly soils with portland cement

    Science.gov (United States)

    Piskunov, Maksim; Karzin, Evgeny; Lukina, Valentina; Lukinov, Vitaly; Kholkin, Anatolii

    2017-10-01

    Stabilization of marlous soils with Portland cement will increase the service life of motor roads in areas where marl is used as a local road construction material. The result of the conducted research is the conclusion about the principal possibility of stabilization of marlous soils with Portland cement, and about the optimal percentage of the mineral part and the binding agent. When planning the experiment, a simplex-lattice plan was implemented, which makes it possible to obtain a mathematical model for changing the properties of a material in the form of polynomials of incomplete third order. Brands were determined for compressive strength according to GOST 23558-94 and variants of stabilized soils were proposed for road construction.

  11. Porosity and liquid absorption of cement paste

    DEFF Research Database (Denmark)

    Krus, M.; Hansen, Kurt Kielsgaard; Kunzel, H. M.

    1997-01-01

    are not accessible to the smaller helium atoms. Considering the results of dilatation tests both before and after water and hexane saturation, it seems possible that a contraction of capillary pores due to moisture-related swelling of the cement gel leads to the non-linear water absorption over the square root......The moisture behaviour of building materials exposed to the natural climate is largely dependent on their water absorption. In contrast to most building stones, cementitious materials like concrete do not exhibit a water absorption that is proportional to the square root of time. There must...... be a slowing-down effect which is related to water because the absorption of organic liquids, such as hexane, is quite normal. Measurements of the porosity of hardened cement paste determined by helium pycnometry and water saturation show that water molecules can enter spaces in the microstructure which...

  12. Religion and new immigrants' labor market entry in Western Europe

    NARCIS (Netherlands)

    Koenig, Matthias; Maliepaard, Mieke|info:eu-repo/dai/nl/313869278; Güveli, Ayse

    2016-01-01

    This paper analyzes the effects of religious participation upon a major socio-economic integration outcome, namely employment, among recent Christian and Muslim newcomers in three Western European destination countries: Germany, the Netherlands, and Great Britain. The paper revisits theoretical

  13. Estimating the chloride transport in cement paste

    Directory of Open Access Journals (Sweden)

    Princigallo, A.

    2012-06-01

    Full Text Available A method was developed to measure the diffusion coefficient of chloride ions in cement paste based on an analytical solution to Fick’s 2nd law in a cylindrical coordinate system. This natural method yielded diffusivity results within as little as a month. Testing time was reduced by exploiting the three-dimensional inward flux in the specimen. In an attempt to determine the saturation concentration, dense portland cement pastes were exposed to a concentrated chloride solution. The method proved to be useful for exploring cement hydration-induced changes in the diffusion coefficient of cement paste.

    Se ha desarrollado un método para medir el coeficiente de difusión de los iones cloruro en la pasta de cemento, partiendo de una aplicación analítica de la segunda ley de Fick en un sistema de coordinadas cilíndrico. Este método, que es natural, demostró ser capaz de producir resultados de difusividad en tan solo un mes. Se consiguió reducir el tiempo de ensayo mediante el aprovechamiento de la tridimensionalidad del flujo desde el exterior al interior de la probeta. A fin de determinar la concentración de saturación, se sometieron las pastas de cemento Portland a una disolución de cloruros concentrada. Este método resultó ser útil en el estudio de los cambios del coeficiente de difusión de la pasta de cemento provocados por las reacciones de hidratación que tienen lugar en esta.

  14. Sidoarjo Mud: A Potential Cement Replacement Material

    OpenAIRE

    Biyanto T.R.; Masilamani M.B.; Bayuaji R.; Nuruddin M.F.

    2010-01-01

    This paper presents an experimental and analytical research conducted to study the properties of mortar when treated Sidoarjo mud was added into the mix replacing partially the cement content. The replacements were done at 0, 5, 10, 15, and 20%. Compression, tensile, porosity and Ultrasonic Pulse Velocity (UPV) tests were conducted to evaluate the effect of Sidoarjo mud in mortar. Analyses on the mud were also conducted through X-ray diffraction (XRD), X-ray Fluorescence (XRF), and scanning e...

  15. Quantitative characterization of the microstructure of fresh cement paste via random packing of polydispersed Platonic cement particles

    International Nuclear Information System (INIS)

    Xu, W X; Chen, H S

    2012-01-01

    On a microscopic scale, fresh cement paste is composed of random packing of irregular cement particles, and their initial packing behavior plays an important role in microstructural evolution. The preponderance of previous works has focused on the microstructure model by random packing of three-dimensional spheroidal particles, and little is known about non-spheroidal particles. In this paper, a modified cement particle size distribution function is used to facilitate the particle size distribution of convex polyhedral cement particles. Based on an overlapping detection algorithm, the microstructure model of fresh cement paste is simulated by the random sequential packing of Platonic cement particles of various sizes. Applying stereological tools and the serial sectioning analysis technique, the modeling microstructure composed of polydispersed Platonic cement particles is characterized and compared with that of ellipsoidal cement particles with various aspect ratios. The statistical results are investigated to evaluate the influence of cement particle shape on the microstructure of fresh cement paste. Finally, with the derived experimental and numerical results of microstructural parameters, the reliability of the statistical results is verified. (paper)

  16. Retention of metal-ceramic crowns with contemporary dental cements.

    Science.gov (United States)

    Johnson, Glen H; Lepe, Xavier; Zhang, Hai; Wataha, John C

    2009-09-01

    New types of crown and bridge cement are in use by practitioners, and independent studies are needed to assess their effectiveness. The authors conducted a study in three parts (study A, study B, and study C) and to determine how well these new cements retain metal-ceramic crowns. The authors prepared teeth with a 20-degree taper and a 4-millimeter length. They cast high-noble metal-ceramic copings, then fitted and cemented them with a force of 196 newtons. The types of cements they used were zinc phosphate, resin-modified glass ionomer, conventional resin and self-adhesive modified resin. They thermally cycled the cemented copings, then removed them. They recorded the removal force and calculated the stress of dislodgment by using the surface area of each preparation. They used a single-factor analysis of variance to analyze the data (alpha = .05). The mean stresses necessary to remove crowns, in megapascals, were 8.0 for RelyX Luting (3M ESPE, St. Paul, Minn.), 7.3 for RelyX Unicem (3M ESPE), 5.7 for Panavia F (Kuraray America, New York) and 4.0 for Fuji Plus (GC America, Alsip, Ill.) in study A; 8.1 for RelyX Luting, 2.6 for RelyX Luting Plus (3M ESPE) and 2.8 for Fuji CEM (GC America) in study B; and 4.9 for Maxcem (Kerr, Orange, Calif.), 4.0 for BisCem (Bisco, Schaumburg, Ill.), 3.7 for RelyX Unicem Clicker (3M ESPE), 2.9 for iCEM (Heraeus Kulzer, Armonk, N.Y.) and 2.3 for Fleck's Zinc Cement (Keystone Industries, Cherry Hill, N.J.) in study C. Powder-liquid versions of new cements were significantly more retentive than were paste-paste versions of the same cements. The mean value of crown removal stress for the new self-adhesive modified-resin cements varied appreciably among the four cements tested. All cements retained castings as well as or better than did zinc phosphate cement. Powder-liquid versions of cements, although less convenient to mix, may be a better clinical choice when crown retention is an issue. All cements tested will retain castings

  17. Low level radwaste packaging: why not cement

    International Nuclear Information System (INIS)

    Wilson, R.B.

    1978-01-01

    Over the past several years many words have been expended in a quest to define a variety of competing radioactive waste immobilization technologies. With the more recent recognition of the technical pitfalls of urea-formaldehyde (UF) a liquid chemical binder considered as optimum less than two years ago, utilities, architect-engineers and systems vendors find themselves in a technology void, awaiting the inevitable breakthrough which will identify the perfect immobilization agent. The culmination of these pressures has brought about the introduction of new immobilization technologies including: one which offers both volume reduction and immobilization in yet another new binder agent; the costly development of highly sophisticated volume reduction systems, the highly-concentrated products from which may pose as-yet unknown immobilization problems; and, the marketing of several new more expensive liquid chemical binders which are reputed to have eliminated the kinds of problems associated with urea-formaldehyde. This paper addresses these issues by coming full circle and arriving back at the initial approach employed for low level radwaste immobilization, the use of cement. Based on an evaluation of the three principal competing immobilization approaches, liquid chemical, bitumen and cement, the merits and drawbacks of each is examined. As will be described, an objective assessment of these competing technologies has resulted in a somewhat surprising conclusion that, while none of the approaches is without disadvantages, cement can be shown to offer the most reliable, versatile long-term solution to today's needs

  18. Application of tracer technique in cement industry

    International Nuclear Information System (INIS)

    Baran'ai, L.

    1979-01-01

    Application is stated of the radioisotope indication method in the cement industry. The method was applied in three directions. In the first direction, by means of labelling of 300 steel mill balls by cobalt-60, wear of them was examined. The degree of wear of milling balls in the process of milling was determined according to the decrease of their weight. Radioactive label served only for tracing controll balls. In the second direction, according to the natural radioactivity being presented in ashes by radioisotopes radium-226 and thorium-229, amount of ashes in the products of cement milling was determined (in the mill product, cement product, flying dust and back loading groats). In the third direction, by means of labelling of definite fractions of mille by radioisotope gold-198, optimization of technological parameters of silos were raw meal is homogenization. The following technological parameters have been established: amount of homogenized material; time of homogenization and frequency of intensity changing of supplied compressed air jet [ru

  19. Global CO2 emissions from cement production

    Science.gov (United States)

    Andrew, Robbie M.

    2018-01-01

    The global production of cement has grown very rapidly in recent years, and after fossil fuels and land-use change, it is the third-largest source of anthropogenic emissions of carbon dioxide. The required data for estimating emissions from global cement production are poor, and it has been recognised that some global estimates are significantly inflated. Here we assemble a large variety of available datasets and prioritise official data and emission factors, including estimates submitted to the UNFCCC plus new estimates for China and India, to present a new analysis of global process emissions from cement production. We show that global process emissions in 2016 were 1.45±0.20 Gt CO2, equivalent to about 4 % of emissions from fossil fuels. Cumulative emissions from 1928 to 2016 were 39.3±2.4 Gt CO2, 66 % of which have occurred since 1990. Emissions in 2015 were 30 % lower than those recently reported by the Global Carbon Project. The data associated with this article can be found at https://doi.org/10.5281/zenodo.831455.

  20. Leaching tests of cemented organic radioactive waste

    International Nuclear Information System (INIS)

    Calabria, Jaqueline A. Almeida; Haucz, Maria Judite A.; Tello, Cledola Cassia O.

    2011-01-01

    The use of radioisotopes in research, medical and industrial activities generates organic liquid radioactive wastes. At Centro de Desenvolvimento da Tecnologia Nuclear (CDTN) are produced organic liquid wastes from different sources, one of these are the solvent extraction activities, whose the waste volume is the largest one. Therefore a research was carried out to treat them. Several techniques to treat organic liquid radioactive wastes have been evaluated, among them incineration, oxidation processes, alkaline hydrolysis, distillation, absorption and cementation. Laboratory experiments were accomplished to establish the most adequate process in order to obtain qualified products for storage and disposal. Absorption followed by cementation was the procedure used in this study, i.e. absorbent substances were added to the organic liquid wastes before mixing with the cement. Initially were defined the absorbers, and evaluated the formulation in relation to the compressive strength of its products. Bentonite from different suppliers (B and G) and vermiculite in two granulometries (M - medium and F - small) were tested. In order to assess the product quality the specimens were submitted to the leaching test according the Standard ISO 6961 and its results were evaluated. Then they were compared with the values established by Standard CNEN NN 6.09 A cceptance criteria for waste products to be disposed , to verify if they meet the requirements for safely storage and disposal. Through this study the best formulations to treat the organic wastes were established. (author)

  1. Effective Permeability Change in Wellbore Cement with Carbon Dioxide Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Um, Wooyong; Jung, Hun Bok; Martin, Paul F.; McGrail, B. Peter

    2011-11-01

    Portland cement, a common sealing material for wellbores for geological carbon sequestration was reacted with CO{sub 2} in supercritical, gaseous, and aqueous phases at various pressure and temperature conditions to simulate cement-CO{sub 2} reaction along the wellbore from carbon injection depth to the near-surface. Hydrated Portland cement columns (14 mm diameter x 90 mm length; water-to-cement ratio = 0.33) including additives such as steel coupons and Wallula basalt fragments were reacted with CO{sub 2} in the wet supercritical (the top half) and dissolved (the bottom half) phases under carbon sequestration condition with high pressure (10 MPa) and temperature (50 C) for 5 months, while small-sized hydrated Portland cement columns (7 mm diameter x 20 mm length; water-to-cement ratio = 0.38) were reacted with CO{sub 2} in dissolved phase at high pressure (10 MPa) and temperature (50 C) for 1 month or with wet CO{sub 2} in gaseous phase at low pressure (0.2 MPa) and temperature (20 C) for 3 months. XMT images reveal that the cement reacted with CO{sub 2} saturated groundwater had degradation depth of {approx}1 mm for 1 month and {approx}3.5 mm for 5 month, whereas the degradation was minor with cement exposure to supercritical CO{sub 2}. SEM-EDS analysis showed that the carbonated cement was comprised of three distinct zones; the innermost less degraded zone with Ca atom % > C atom %, the inner degraded zone with Ca atom % {approx} C atom % due to precipitation of calcite, the outer degraded zone with C atom % > Ca atom % due to dissolution of calcite and C-S-H, as well as adsorption of carbon to cement matrix. The outer degraded zone of carbonated cement was porous and fractured because of dissolution-dominated reaction by carbonic acid exposure, which resulted in the increase in BJH pore volume and BET surface area. In contrast, cement-wet CO{sub 2}(g) reaction at low P (0.2 MPa)-T (20 C) conditions for 1 to 3 months was dominated by precipitation of micron

  2. Bone cement implantation syndrome in hip replacement procedure

    Directory of Open Access Journals (Sweden)

    Onur Palabiyik

    2013-06-01

    Full Text Available Total hip replacement procedures are common in geriatric patients with osteoarthrosis of the hip or femur fracture. We planned combined spinal epidural anesthesia for total hip replacement operation due to femur fracture in a ninety-five female case with cardiorespiratory failure. Although the regional anesthesia had applied smoothly, intraoperative cardiac arrest during the placement of cement was thought to be a case with bone cement implantation syndrome. Bone cement implantation syndrome is occured in cemented prosthesis operations and a life-threatened complication. Clinic presentation is characterized by hypoxia, hypotension, unexpected loss of consciousness and cardiac arrest. Mortality rate due to bone cement implantation syndrome is approximately 0.1%. In this present, we examined bone cement implantation syndrome, which is a severe complication. [J Contemp Med 2013; 3(2.000: 121-124

  3. Portland-pfa cement: a comparison between intergrinding and blending

    Energy Technology Data Exchange (ETDEWEB)

    Monk, M.

    1983-09-01

    Portland-pfa cements containing 20-40% (by weight) pfa have been prepared in the laboratory both by intergrinding the ashes with clinker and by blending with cement. Cement properties have been assessed according to BS 4550 and scanning electron microscopy was used to examine the effects of grinding upon the pfa particles. The work has shown that intergrinding leads to an improvement in the water-reducing properties of coarse pfas and also in their pozzolanic activity as indicated by compressive strength development at later ages. Setting times have been found to be essentially the same for blended and interground cements, both being considerably longer than for typical ordinary Portland cements. Thus the results of this investigation indicate that, provided pfa's are chemically acceptable, they can be used for Portland-pfa cement manufacture by intergrinding irrespective of their coarseness.

  4. Setting, hardening and resorption of calcium phosphate hydraulic cements.

    Science.gov (United States)

    Lemaitre, J; Munting, E; Mirtchi, A A

    1992-01-01

    Two examples of calcium phosphate hydraulic cements (CPHC) are presented. Type I cements consist in mixtures of beta-tricalcium phosphate (beta-TCP) and monocalcium phosphate monohydrate (MCPM), to which some plaster of Paris (CSH) is added as a setting retardant. Type II cements consist in mixtures of beta-TCP, dicalcium phosphate dihydrate (DCPD) and calcium carbonate (CC), to which some hydroxyapatite (HAP) is added as a setting accelerator. The setting time of these cements ranges from a few minutes up to a few hours, according to their composition and the amount of mixing water. Tensile strengths ranging from 1.2 up to 3.5 MPa have been recorded on cements which porosity ranged from 38 up to 55 vol%. In-vivo experiments on dogs have shown the perfect biocompatibility and resorbability of cement I.

  5. Early-age Performance of Cement Combination Concrete

    Directory of Open Access Journals (Sweden)

    Samuel Olufemi Folagbade

    2017-03-01

    Full Text Available Heat of hydration up to 72 hours and compressive strength up to 7 days of Portland cement and 17 binary and ternary cements containing fly ash, silica fume, and metakaolin, at a water/cement ratio of 0.50 and addition contents of 20%, 35%, and 55%, were used to examine the early-age performance of concrete. Results revealed that early-age performance depends on the fineness, heat of hydration, and dilution effect of cement combinations. Fly ash, due to dilution effect, reduces the heat of hydration and compressive strength. Using silica fume and metakaolin with increasing content of up to 10% as binary and ternary cement components, due to their fineness and increased heat of hydration, supports the strength development. Most of the cement combinations met the standard of strength requirements for ordinary early-age performance of concrete, while only half of it satisfied the standard for high early-age performance.

  6. Formulating a low-alkalinity cement for radioactive waste repositories

    Energy Technology Data Exchange (ETDEWEB)

    Coumes, C. Cau Dit; Courtois, S.; Leclercq, S.; Bourbon, X

    2004-07-01

    A multi-annual research program has been launched in January 2003 by CEA, EDF and ANDRA in order to formulate and characterize low-alkalinity and low-heat cements which would be compatible with an underground waste repository environment. Four types of bindings have been investigated: binary blends of Portland cement and silica fume or metakaolin, as well as ternary blends of Portland cement, fly ash and silica fume or metakaolin. Promising results have been obtained with a mixture comprising 37.5% Portland cement, 32.5% silica fume, and 30% fly ash: pH of water in equilibrium with fully hydrated cement is below 11. Moreover, silica fume compensates for the low reactivity of fly ash, while fly ash allows to reduce water demand, heat release, and dimensional variations of cement pastes and mortars. (authors)

  7. Immobilization of radioactive waste in cement based matrices

    International Nuclear Information System (INIS)

    Glasser, F.P.; Rahman, A.A.; Macphee, D.; McCulloch, C.E.; Angus, M.J.

    1985-06-01

    The kinetics of reaction between cement and clinoptilolite are elucidated and rate equations containing temperature dependent constants derived for this reaction. Variations in clinoptilolite particle size and their consequences to reactivity are assessed. The presence of pozzolanic agents more reactive than clinoptilolite provides sacrificial agents which are partially effective in lowering the clinoptilolite reactivity. Blast furnace slag-cements have been evaluated and the background literature summarized. Experimental studies of the pore fluid in matured slag-cements show that they provide significantly more immobilization for Cs than Portland cement. The distribution of Sr in cemented waste forms has been examined, and it is shown that most of the chemical immobilization potential in the short term is likely to be associated with the aluminate phases. The chemical and structural nature of these are described. Carbonation studies on real cements are summarized. (author)

  8. Possibilities of using aluminate cements in high-rise construction

    Science.gov (United States)

    Kaddo, Maria

    2018-03-01

    The article describes preferable ways of usage of alternative binders for high-rise construction based on aluminate cements. Possible areas of rational use of aluminate cements with the purpose of increasing the service life of materials and the adequacy of the durability of materials with the required durability of the building are analyzed. The results of the structure, shrinkage and physical and mechanical properties of concrete obtained from dry mixes on the base of aluminate cements for self-leveling floors are presented. To study the shrinkage mechanism of curing binders and to evaluate the role of evaporation of water in the development of shrinkage was undertaken experiment with simple unfilled systems: gypsum binder, portland cement and «corrosion resistant high alumina cement + gypsum». Principle possibility of binder with compensated shrinkage based on aluminate cement, gypsum and modern superplasticizers was defined, as well as cracking resistance and corrosion resistance provide durability of the composition.

  9. Modification of Wood Fiber for Use in Cement Board

    Science.gov (United States)

    Han, F. Q.; Tan, X.; Zhao, F. Q.

    2017-12-01

    When ordinary Portland cement is used for wood fiber cement (WFC) board, the setting time is too long, even hard to solidify. Three methods can be used for wood fiber modification, i.e., soaking in water, treated with alkali solution and coated with some substances on the fiber surface. The results show that the proper water-cement ratio of WFC paste is 1:1.3 in the case of wood cement ratio being 1:1. The WFC board from modified wood fiber and cement is better than the control samples, in which the combined treatment, i.e. soaking in hot water and then coating with alkali-BFS-EVA slurry, behaves best. It is proved that ordinary Portland cement can be used to produce WFC board, with the modified wood fiber, which can greatly reduce production costs.

  10. Utilization of red mud in cement production: a review.

    Science.gov (United States)

    Liu, Xiaoming; Zhang, Na

    2011-10-01

    Red mud is a solid waste residue of the digestion of bauxite ores with caustic soda for alumina production. Its disposal remains a worldwide issue in terms of environmental concerns. During the past decades, extensive work has been done by a lot of researchers to develop various economic ways for the utilization of red mud. One of the economic ways is using red mud in cement production, which is also an efficient method for large-scale recycling of red mud. This paper provides a review on the utilization of red mud in cement production, and it clearly points out three directions for the use of red mud in cement production, namely the preparation of cement clinkers, production of composite cements as well as alkali-activated cements. In the present paper, the chemical and mineralogical characteristics of red mud are summarized, and the current progresses on these three directions are reviewed in detail.

  11. Cement-Based Materials for Nuclear Waste Storage

    CERN Document Server

    Cau-di-Coumes, Céline; Frizon, Fabien; Lorente, Sylvie

    2013-01-01

    As the re-emergence of nuclear power as an acceptable energy source on an international basis continues, the need for safe and reliable ways to dispose of radioactive waste becomes ever more critical. The ultimate goal for designing a predisposal waste-management system depends on producing waste containers suitable for storage, transportation and permanent disposal. Cement-Based Materials for Nuclear-Waste Storage provides a roadmap for the use of cementation as an applied technique for the treatment of low- and intermediate-level radioactive wastes.Coverage includes, but is not limited to, a comparison of cementation with other solidification techniques, advantages of calcium-silicate cements over other materials and a discussion of the long-term suitability and safety of waste packages as well as cement barriers. This book also: Discusses the formulation and production of cement waste forms for storing radioactive material Assesses the potential of emerging binders to improve the conditioning of problemati...

  12. Immobilization of radioactive waste in cement-based matrices

    International Nuclear Information System (INIS)

    Glasser, F.P.; Rahman, A.A.; Crawford, R.W.; McCulloch, C.E.; Angus, M.J.

    1984-01-01

    Tobermorite and xonotlite, two synthetic calcium silicate hydrates, improve the Cs retention of cement matrices for Cs, when incorporated at the 6 to 10% level. A kinetic and mechanistic scheme is presented for the reaction of fine grained, Cs-loaded clinoptilolite with cement. The Magnox waste form reacts quickly with cement, leading to an exchange of carbonate between waste form and cement components. Carbonation of cements leads to a marked improvement in their physical properties of Cs retentivity. Diffusion models are presented for cement systems whose variable parameters can readily be derived from experimental measurements. Predictions about scaled-up behaviour of large immobilized masses are applied to extrapolation of laboratory scale results to full-size masses. (author)

  13. Chemical and physical properties of bone cement for vertebroplasty

    Directory of Open Access Journals (Sweden)

    Po-Liang Lai

    2013-08-01

    Full Text Available Vertebral compression fracture is the most common complication of osteoporosis. It may result in persistent severe pain and limited mobility, and significantly impacts the quality of life. Vertebroplasty involves a percutaneous injection of bone cement into the collapsed vertebrae by fluorescent guide. The most commonly used bone cement in percutaneous vertebroplasty is based on the polymerization of methylmethacrylate monomers to polymethylmethacrylate (PMMA polymers. However, information on the properties of bone cement is mostly published in the biomaterial sciences literature, a source with which the clinical community is generally unfamiliar. This review focuses on the chemistry of bone cement polymerization and the physical properties of PMMA. The effects of altering the portions and contents of monomer liquid and polymer powders on the setting time, polymerization temperature, and compressive strength of the cement are also discussed. This information will allow spine surgeons to manipulate bone cement characteristics for specific clinical applications and improve safety.

  14. Crown retention and flexural strength of eight provisional cements.

    Science.gov (United States)

    Lawson, Nathaniel C; Burgess, John O; Mercante, Donald

    2007-12-01

    Few studies have compared the retention of resin-based and zinc-oxide noneugenol provisional cements. Crown retention testing is difficult and variable; therefore, a simpler method of testing by using flexural strength is indicated. The purpose of this study was to measure the retention of base metal alloy castings to dentin provided by 8 provisional cements (3 resin-based and 5 zinc oxide) and correlate the retention to their flexural strength. Flexural strength specimens (2.5 x 2.5 x 22 mm) were made of each cement. The specimens were placed in a 3-point bending testing mode and loaded at 1 mm/min until failure. Ten extracted teeth were milled to a standardized complete crown preparation, fitted with Rexillium III castings, and cemented with each provisional cement. The specimens were subjected to a tensile load (1 mm/min) until failure in a universal testing machine. The flexural strength for each cement was calculated in MPa and correlated to the retention. A 1-way ANOVA and Tukey HSD post hoc analysis were used to determine significant intergroup differences (alpha=.05). Linear regression was used to correlate flexural strength and crown retention (alpha=.05). Significant differences were found in the flexural strengths and retention provided by the various cements. Flexure strength was correlated with cement retention for resin-based cements (r=0.998) but not zinc-oxide noneugenol cements (r=0.058). Based on a 20-degree preparation, stronger cements provide increased retention. Therefore, the desired amount of retention should be based on both the cement and a clinical evaluation of the preparation.

  15. Personal exposure to inhalable cement dust among construction workers.

    Science.gov (United States)

    Peters, Susan; Thomassen, Yngvar; Fechter-Rink, Edeltraud; Kromhout, Hans

    2009-01-01

    Objective- A case study was carried out to assess cement dust exposure and its determinants among construction workers and for comparison among workers in cement and concrete production.Methods- Full-shift personal exposure measurements were performed and samples were analysed for inhalable dust and its cement content. Exposure variability was modelled with linear mixed models.Results- Inhalable dust concentrations at the construction site ranged from 0.05 to 34 mg/m(3), with a mean of 1.0 mg/m(3). Average concentration for inhalable cement dust was 0.3 mg/m(3) (GM; range 0.02-17 mg/m(3)). Levels in the ready-mix and pre-cast concrete plants were on average 0.5 mg/m(3) (GM) for inhalable dust and 0.2 mg/m(3) (GM) for inhalable cement dust. Highest concentrations were measured in cement production, particularly during cleaning tasks (inhalable dust GM = 55 mg/m(3); inhalable cement dust GM = 33 mg/m(3)) at which point the workers wore personal protective equipment. Elemental measurements showed highest but very variable cement percentages in the cement plant and very low percentages during reinforcement work and pouring. Most likely other sources were contributing to dust concentrations, particularly at the construction site. Within job groups, temporal variability in exposure concentrations generally outweighed differences in average concentrations between workers. 'Using a broom', 'outdoor wind speed' and 'presence of rain' were overall the most influential factors affecting inhalable (cement) dust exposure.Conclusion- Job type appeared to be the main predictor of exposure to inhalable (cement) dust at the construction site. Inhalable dust concentrations in cement production plants, especially during cleaning tasks, are usually considerably higher than at the construction site.

  16. Expansive cements for the manufacture of the concrete protective bandages

    Science.gov (United States)

    Yakymechko, Yaroslav; Voloshynets, Vladyslav

    2017-12-01

    One of the promising directions of the use of expansive cements is making the protective bandages for the maintenance of pipelines. Bandages expansive application of the compositions of the pipeline reinforce the damaged area and reduce stress due to compressive stress in the cylindrical area. Such requirements are best suited for expansive compositions obtained from portland cement and modified quicklime. The article presents the results of expansive cements based on quick lime in order to implement protective bandages pipelines.

  17. Marginal Fit and Retention Strength of Zirconia Crowns Cemented by Self-adhesive Resin Cements.

    Science.gov (United States)

    Pilo, R; Folkman, M; Arieli, A; Levartovsky, S

    The absolute marginal gap (AMG) precementation and postcementation and the retention of zirconia crowns cemented to standardized molar preparations (4×10) by self-adhesive resin cements (SARCs) were evaluated. The following SARCs were used: RelyX U-200 (RXU200; 3M ESPE, Seefeld, Germany), SmartCem 2 (SC2; Dentsply, Milford, DE, USA), and G-Cem Automix (GCA; GC, Alsip, IL, USA). The control adhesive resin cement was Panavia 21 (PAN; Kuraray Dental Co Ltd, Osaka, Japan). Twenty measuring locations at a constant interval along the margins were marked, and the AMG was measured by an image analysis system connected to a stereomicroscope (20×). The cemented copings were aged 270 days at 100% humidity and 37°C and then underwent 10,000 thermal cycles, 5°C-55°C. After aging, the crowns were tested for retention, and the debonded surfaces were examined at 3× magnification. The mean marginal gaps precementation and postcementation were 34.8 ± 17.4 μm and 72.1 ± 31 μm, respectively, with no statistically significant differences between the cements. A significant difference ( p≤0.001) in retention between the cements was found. The highest values were obtained for SC2 and GCA (1385 Pa and 1229 Pa, respectively), but these presented no statistically significant differences. The lowest values were found for PAN and RXU200 (738 Pa and 489 Pa, respectively), but these showed no statistically significant differences. The predominant mode of failure in all of the groups was mixed, and no correlations were found between marginal gap and retention.

  18. The Prevalence and Management of Systemic Amyloidosis in Western Countries

    NARCIS (Netherlands)

    Nienhuis, Hans L A; Bijzet, Johan; Hazenberg, Bouke P C

    BACKGROUND: Amyloidosis has been a mystery for centuries, but research of the last decennia has clarified many of the secrets of this group of diseases. A protein-based classification of amyloidosis helps to understand problems that were part of the obsolete clinical classification in primary,

  19. Upolu Island, Western Samoa

    Science.gov (United States)

    2000-01-01

    Island nations in the South Pacific Ocean experience natural disasters associated with typhoons, and with their proximity to the Pacific Ocean's 'Ring of Fire.' This radar image shows most of the northern coast of the island of Upolu in the nation of Western Samoa. Disaster managers use digital elevation models (DEMs) generated from radar data to assist in research toward disaster mitigation and management. Geologists also use DEM data of volcanic features, such as the line of circular craters in this image, to study eruption rates and volumes, and volcanic landform evolution. The capital of Western Samoa, Apia, is in the lower left of the image.Angular black areas in the image are areas where steep topography causes holes in the data; these holes can be filled in by collecting data at other look directions. Color represents topography and intensity represents across-section of the radar backscatter. Since rough areas return more of the incident signal, they appear brighter on the image than relatively smooth areas, such as the ocean surface , along the left side of the image.This image was acquired by the AIRborne Synthetic Aperture (AIRSAR) radar instrument aboard a DC-8 aircraft operated out of NASA's Dryden Flight Research Center. AIRSAR collects fully polarimetric data at three wavelengths; C-band (0.057 meter), L-band (0.25 meter) and P-band (0.68 meter). AIRSAR also collects cross-track and along track interferometric data that results in topographic measurements and motion detection, respectively.This image was collected during the Pacific Rim mission, a three-month mission from July to October 2000 that collected data at over 200 sites in eighteen countries and territories around the Pacific Rim. AIRSAR is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise,Washington, D.C.Size: 10 km (6.2 miles) x 63 km (37.3 miles) Location: 14.16 deg. North lat., 171.75 deg. West Orientation: North towards the left side of

  20. Studies on Soil Cements : 2 — Physicochemical Properties of the Hardened Soil Cement Pastes.

    OpenAIRE

    Abo El Enein, A. [صلاح عبد الغني ابو العينين; Abdel-Moez, M.S.; Mikhail, R. Sh.; Hekal, E.E.

    1982-01-01

    Various hardened soil-cement pastes were prepared from dry mixtures of montmorillonite clay and portland cement clinker by using different W/C ratios of 0.20, 40, 0.60 and 0.80 and cured in air for various ages. Compressive strength tests were done on the hardened fresh pastes, while the nitrogen adsorption studies were carried out on the D-dried specimens. The variations in compressive strength could be related to the physicochemical properties and the pore structure of the hardened pastes. ...

  1. Effect of cement types and timing of cementation on the retentive bond strength of fiber posts

    OpenAIRE

    Aleisa, Khalil; Al-Dwairi, Ziad; Alghabban, Rawda; Glickman, Gerald; Hsu, Ming-Lun

    2012-01-01

    Background/purpose: To evaluate the effect of early versus delayed post space preparation and cementation and the types of cement on the retention of fiber posts in canals obturated using an epoxy resin sealer. Materials and methods: Seventy-two extracted single-rooted teeth with straight root canals were decoronated and obturated with gutta-percha and an epoxy resin sealer (AH26). Post spaces were prepared to a depth of 8 mm and 1.5 mm diameter. Parallel-sided, prefabricated fiber posts w...

  2. Apparatus and method for vibrating a casing string during cementing

    International Nuclear Information System (INIS)

    Rankin, R.E.; Rankin, K.T.

    1992-01-01

    This patent describes a method of cementing a string of casing in a well. It comprises: securing a vibrating device into the string of casing near the lower end of the string of casing; lowering the string of casing into the well to the desired depth; pumping a cement slurry down the string of casing; causing a portion of the cement slurry being pumped down the string of casing to vibrate the vibrating device; and wherein the vibrating device is secured in the string of casing by cementing the vibrating device within a sub, then securing the sub into the string of casing prior to lowering the string of casing into the well

  3. Nanoparticulate fillers improve the mechanical strength of bone cement.

    Science.gov (United States)

    Gomoll, Andreas H; Fitz, Wolfgang; Scott, Richard D; Thornhill, Thomas S; Bellare, Anuj

    2008-06-01

    Polymethylmethacrylate (PMMA-) based bone cement contains micrometer-size barium sulfate or zirconium oxide particles to radiopacify the cement for radiographic monitoring during follow-up. Considerable effort has been expended to improve the mechanical qualities of cements, largely through substitution of PMMA with new chemical structures. The introduction of these materials into clinical practice has been complicated by concerns over the unknown long-term risk profile of these new structures in vivo. We investigated a new composite with the well characterized chemical composition of current cements, but with nanoparticles instead of the conventional, micrometer-size barium sulfate radiopacifier. In this study, we replaced the barium sulfate microparticles that are usually present in commercial PMMA cements with barium sulfate nanoparticles. The resultant "microcomposite" and "nanocomposite" cements were then characterized through morphological investigations such as ultra-small angle X-ray scattering (USAXS) and scanning electron microscopy (SEM). Mechanical characterization included compression, tensile, compact tension, and fatigue testing. SEM and USAXS showed excellent dispersion of nanoparticles. Substitution of nanoparticles for microparticles resulted in a 41% increase in tensile strain-to-failure (p = 0.002) and a 70% increase in tensile work-of-fracture (p = 0.005). The nanocomposite cement also showed a two-fold increase in fatigue life compared to the conventional, microcomposite cement. In summary, nanoparticulate substitution of radiopacifiers substantially improved the in vitro mechanical properties of PMMA bone cement without changing the known chemical composition.

  4. Microindentation of Polymethyl Methacrylate (PMMA Based Bone Cement

    Directory of Open Access Journals (Sweden)

    F. Zivic

    2011-12-01

    Full Text Available Characterization of polymethyl methacrylate (PMMA based bone cement subjected to cyclical loading using microindentation technique is presented in this paper. Indentation technique represents flexible mechanical testing due to its simplicity, minimal specimen preparation and short time needed for tests. The mechanical response of bone cement samples was studied. Realised microindentation enabled determination of the indentation testing hardness HIT and indentation modulus EIT of the observed bone cement. Analysis of optical photographs of the imprints showed that this technique can be effectively used for characterization of bone cements.

  5. Centralized cement solidification technique for low-level radioactive wastes

    International Nuclear Information System (INIS)

    Matsuda, Masami; Nishi, Takashi; Izumida, Tatsuo; Tsuchiya, Hiroyuki.

    1996-01-01

    A centralized cement solidification system has been developed to enable a single facility to solidify such low-level radioactive wastes as liquid waste, spent ion exchange resin, incineration ash, and miscellaneous solid wastes. Since the system uses newly developed high-performance cement, waste loading is raised and deterioration of waste forms after land burial prevented. This paper describes the centralized cement solidification system and the features of the high-performance cement. Results of full-scale pilot plant tests are also shown from the viewpoint of industrial applicability. (author)

  6. Sodium diethyldithiocarbamate as accelerator of the rate of copper cementation

    Directory of Open Access Journals (Sweden)

    Abeer A. El-Saharty

    2015-12-01

    Full Text Available The effects of Cu2+ ion concentration and temperature on the cementation rate of copper from copper sulphate on zinc and the effect of additives of the organic compound “sodium diethyldithiocarbamate” (NaDDC were studied. It was noticed that the cementation increases significantly by increasing the concentrations of NaDDC. The rate of cementation increased by 58.58−100.31%. Our data showed that sodium diethyldithiocarbamate reacts with the Cu2+ solution giving a complex of copper diethyldithiocarbamate, which enhances the rate of cementation.

  7. Cementing and formation damage; Cimentacao e dano a formacao

    Energy Technology Data Exchange (ETDEWEB)

    Souza, David Soares de [PETROBRAS, BA (Brazil). Distrito de Perfuracao da Bahia. Div. de Tecnicas e Operacoes

    1994-07-01

    This work presents a general perspective on cementing and formation damage. Few relative experiments to the damage to the formation, that they involve the casing activity and cementing, consider all the factors that affect these operations. So that she can analyze the contribution of a primary cementing has in the formation damage , it should be considered, also, the contribution of the drilling fluid and of the operation of the perforation. With base in experimental data of several accomplished studies, it can be concluded that a primary cementing has small, or any, contribution in the decrease of the productivity of an oil well.

  8. The Mechanism of Disintegration of Cement Concrete at High Temperatures

    Directory of Open Access Journals (Sweden)

    Jocius Vytautas

    2016-10-01

    Full Text Available Concrete is a composite material composed of a binder, aggregates, water and additives. Mixing of cement with water results in a number of chemical reactions known as cement hydration. Heating of concrete results in dehydration processes of cement minerals and new hydration products, which disintegrate the microstructure of concrete. This article reviews results of research conducted with Portland and alumina cement with conventional and refractory concrete aggregates. In civic buildings such common fillers as gravel, granite, dolomite or expanded clay are usually used. It is important to point out the differences between fillers because they constitute the majority of the concrete volume.

  9. Analytical method to estimate resin cement diffusion into dentin

    Science.gov (United States)

    de Oliveira Ferraz, Larissa Cristina; Ubaldini, Adriana Lemos Mori; de Oliveira, Bruna Medeiros Bertol; Neto, Antonio Medina; Sato, Fracielle; Baesso, Mauro Luciano; Pascotto, Renata Corrêa

    2016-05-01

    This study analyzed the diffusion of two resin luting agents (resin cements) into dentin, with the aim of presenting an analytical method for estimating the thickness of the diffusion zone. Class V cavities were prepared in the buccal and lingual surfaces of molars (n=9). Indirect composite inlays were luted into the cavities with either a self-adhesive or a self-etch resin cement. The teeth were sectioned bucco-lingually and the cement-dentin interface was analyzed by using micro-Raman spectroscopy (MRS) and scanning electron microscopy. Evolution of peak intensities of the Raman bands, collected from the functional groups corresponding to the resin monomer (C-O-C, 1113 cm-1) present in the cements, and the mineral content (P-O, 961 cm-1) in dentin were sigmoid shaped functions. A Boltzmann function (BF) was then fitted to the peaks encountered at 1113 cm-1 to estimate the resin cement diffusion into dentin. The BF identified a resin cement-dentin diffusion zone of 1.8±0.4 μm for the self-adhesive cement and 2.5±0.3 μm for the self-etch cement. This analysis allowed the authors to estimate the diffusion of the resin cements into the dentin. Fitting the MRS data to the BF contributed to and is relevant for future studies of the adhesive interface.

  10. Characteristics of Cement Solidification of Metal Hydroxide Waste

    Directory of Open Access Journals (Sweden)

    Dae-Seo Koo

    2017-02-01

    Full Text Available To perform the permanent disposal of metal hydroxide waste from electro-kinetic decontamination, it is necessary to secure the technology for its solidification. The integrity tests on the fabricated solidification should also meet the criteria of the Korea Radioactive Waste Agency. We carried out the solidification of metal hydroxide waste using cement solidification. The integrity tests such as the compressive strength, immersion, leach, and irradiation tests on the fabricated cement solidifications were performed. It was also confirmed that these requirements of the criteria of Korea Radioactive Waste Agency on these cement solidifications were met. The microstructures of all the cement solidifications were analyzed and discussed.

  11. Bone cement allocation analysis in artificial cancellous bone structures

    Directory of Open Access Journals (Sweden)

    Ivan Zderic

    2017-01-01

    Conclusion: The simulated leakage path seemed to be the most important adverse injection factor influencing the uniformity of cement distribution. Another adverse factor causing dispersion of this distribution was represented by the simulated bone marrow. However, the rather uniform distribution of the totally injected cement amount, considered as one unit, could be ascribed to the medium viscosity of the used cement. Finally, with its short waiting time of 45 s, the stepwise injection procedure was shown to be ineffective in preventing cement leakage.

  12. Development of nanosilica bonded monetite cement from egg shells

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Huan, E-mail: huanzhou@cczu.edu.cn [Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu (China); Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH (United States); Luchini, Timothy J.F.; Boroujeni, Nariman Mansouri [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH (United States); Agarwal, Anand K.; Goel, Vijay K. [Department of Bioengineering, The University of Toledo, Toledo, OH (United States); Bhaduri, Sarit B. [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH (United States); Division of Dentistry, The University of Toledo, Toledo, OH (United States)

    2015-05-01

    This work represents further effort from our group in developing monetite based calcium phosphate cements (CPC). These cements start with a calcium phosphate powder (MW-CPC) that is manufactured using microwave irradiation. Due to the robustness of the cement production process, we report that the starting materials can be derived from egg shells, a waste product from the poultry industry. The CPC were prepared with MW-CPC and aqueous setting solution. Results showed that the CPC hardened after mixing powdered cement with water for about 12.5 ± 1 min. The compressive strength after 24 h of incubation was approximately 8.45 ± 1.29 MPa. In addition, adding colloidal nanosilica to CPC can accelerate the cement hardening (10 ± 1 min) process by about 2.5 min and improve compressive strength (20.16 ± 4.39 MPa), which is more than double the original strength. The interaction between nanosilica and CPC was monitored using an environmental scanning electron microscope (ESEM). While hardening, nanosilica can bond to the CPC crystal network for stabilization. The physical and biological studies performed on both cements suggest that they can potentially be used in orthopedics. - Highlights: • Cement raw powder is derived from egg shells. • A microwave assisted system is used for preparing monetite bone cement. • Colloidal silica is used to reinforce cement.

  13. Corrosion-resistant Foamed Cements for Carbon Steels

    Energy Technology Data Exchange (ETDEWEB)

    Sugama T.; Gill, S.; Pyatina, T., Muraca, A.; Keese, R.; Khan, A.; Bour, D.

    2012-12-01

    The cementitious material consisting of Secar #80, Class F fly ash, and sodium silicate designed as an alternative thermal-shock resistant cement for the Enhanced Geothermal System (EGS) wells was treated with cocamidopropyl dimethylamine oxide-based compound as foaming agent (FA) to prepare numerous air bubble-dispersed low density cement slurries of and #61603;1.3 g/cm3. Then, the foamed slurry was modified with acrylic emulsion (AE) as corrosion inhibitor. We detailed the positive effects of the acrylic polymer (AP) in this emulsion on the five different properties of the foamed cement: 1) The hydrothermal stability of the AP in 200 and #61616;C-autoclaved cements; 2) the hydrolysis-hydration reactions of the slurry at 85 and #61616;C; 3) the composition of crystalline phases assembled and the microstructure developed in autoclaved cements; 4) the mechanical behaviors of the autoclaved cements; and, 5) the corrosion mitigation of carbon steel (CS) by the polymer. For the first property, the hydrothermal-catalyzed acid-base interactions between the AP and cement resulted in Ca-or Na-complexed carboxylate derivatives, which led to the improvement of thermal stability of the AP. This interaction also stimulated the cement hydration reactions, enhancing the total heat evolved during cement’s curing. Addition of AP did not alter any of the crystalline phase compositions responsible for the strength of the cement. Furthermore, the AP-modified cement developed the porous microstructure with numerous defect-free cavities of disconnected voids. These effects together contributed to the improvement of compressive-strength and –toughness of the cured cement. AP modification of the cement also offered an improved protection of CS against brine-caused corrosion. There were three major factors governing the corrosion protection: 1) Reducing the extents of infiltration and transportation of corrosive electrolytes through the cement layer deposited on the underlying CS

  14. The Many Crises of Western Journalism

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Kleis

    of professional journalism in existential terms; the second focuses on the weaknesses of the professional model itself; the third defines the crisis in symbolic terms, as a morally problematic relation among journalists, citizens, and power holders. These three crisis frameworks raise different questions......The digital-cum-economic crisis facing Western journalism differs in subtle but significant ways from country to country, and fierce struggles play out between different parties over how to interpret the situation and how to confront it. This chapter presents a comparative analysis of how...... journalists, media executives, and media policymakers in six different Western democracies (Finland, France, Germany, Italy, the UK, and the US) employ three distinctive frameworks to interpret the state of professional journalism in their country. The first is an economic frame that defines the crisis...

  15. Country-of-origin effect and consumer brand perception

    DEFF Research Database (Denmark)

    Iacob, Andreea

    This dissertation investigates the impact of country of origin on the brand perception of consumers from developed and emerging countries. Particularly, the aim is to explore the impact of the country of origin on the Western consumers’ brand perception of high involvement products with multiple ...... countries of origin and the Central Eastern European consumers’ brand perception of low involvement products from developed countries. It comprises a summary report, consisting of an introduction, a methodology chapter, a conclusions chapter and four research papers.......This dissertation investigates the impact of country of origin on the brand perception of consumers from developed and emerging countries. Particularly, the aim is to explore the impact of the country of origin on the Western consumers’ brand perception of high involvement products with multiple...

  16. Energy Efficiency Improvement and Cost Saving Opportunities for Cement Making. An ENERGY STAR Guide for Energy and Plant Managers

    Energy Technology Data Exchange (ETDEWEB)

    Galitsky, Christina; Worrell, Ernst; Galitsky, Christina

    2008-01-01

    The cost of energy as part of the total production costs in the cement industry is significant, warranting attention for energy efficiency to improve the bottom line. Historically, energy intensity has declined, although more recently energy intensity seems to have stabilized with the gains. Coal and coke are currently the primary fuels for the sector, supplanting the dominance of natural gas in the 1970s. Most recently, there is a slight increase in the use of waste fuels, including tires. Between 1970 and 1999, primary physical energy intensity for cement production dropped 1 percent/year from 7.3 MBtu/short ton to 5.3 MBtu/short ton. Carbon dioxide intensity due to fuel consumption and raw material calcination dropped 16 percent, from 609 lb. C/ton of cement (0.31 tC/tonne) to 510 lb. C/ton cement (0.26 tC/tonne). Despite the historic progress, there is ample room for energy efficiency improvement. The relatively high share of wet-process plants (25 percent of clinker production in 1999 in the U.S.) suggests the existence of a considerable potential, when compared to other industrialized countries. We examined over 40 energy efficient technologies and measures and estimated energy savings, carbon dioxide savings, investment costs, and operation and maintenance costs for each of the measures. The report describes the measures and experiences of cement plants around the wold with these practices and technologies. Substantial potential for energy efficiency improvement exists in the cement industry and in individual plants. A portion of this potential will be achieved as part of (natural) modernization and expansion of existing facilities, as well as construction of new plants in particular regions. Still, a relatively large potential for improved energy management practices exists.

  17. The effects of crown venting or pre-cementing of CAD/CAM-constructed all-ceramic crowns luted on YTZ implants on marginal cement excess.

    Science.gov (United States)

    Zaugg, Lucia K; Zehnder, Isabella; Rohr, Nadja; Fischer, Jens; Zitzmann, Nicola U

    2018-01-01

    The purpose of this study was to analyze the cement excess produced when cementing CAD/CAM-fabricated lithium disilicate (L) or zirconium dioxide (Z) crowns using adhesive cement (A) or resin-modified glass ionomer cement (B). Three different cementation techniques were applied: palatal venting (PV), pre-cementation with custom analogs (CA), and conventional standard procedure (SP). Seventy-two crowns (36 each material) were assigned to 12 experimental groups depending on the restoration material (L, Z), type of cement (A, B), and cementation technique (PV, CA, SP). Weight measurements were taken during cementation, and the amounts of excess cement, cement retained in crown, and relative excess cement were calculated and statistically analyzed. A significant direct relation between the amounts of cement applied and excess cement was observed in groups CA and SP. Vented crowns showed least amounts of marginal excess cement (0.8 ± 0.3 μl) followed by CA (4.2 ± 1.1 μl) and SP (8.8 ± 2.5 μl; p cement (95%CI: 28.4, 35.7) was produced than in the SP group (p cement (A) than of glass ionomer cement (B) were retained in crowns. Using crown venting was the most effective measure to reduce the amount of marginal excess cement, followed using a pre-cementation device. To keep the marginal excess cement of one-piece zirconia implants to a minimum, both techniques should be considered for clinical application. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Correlation between the cytotoxicity of self-etching resin cements and the degree of conversion

    Directory of Open Access Journals (Sweden)

    Luís FSA Morgan

    2015-01-01

    Conclusion: These results indicate that photopolymerization of dual cure self-etching resin cements decrease toxic effects on cell culture. Adequate photopolymerization should be considered during cementation when using dual polymerization self-etching resin cements.

  19. A comparison of retentive strength of implant cement depending on various methods of removing provisional cement from implant abutment

    Science.gov (United States)

    Keum, Eun-Cheol

    2013-01-01

    PURPOSE This study evaluated the effectiveness of various methods for removing provisional cement from implant abutments, and what effect these methods have on the retention of prosthesis during the definitive cementation. MATERIALS AND METHODS Forty implant fixture analogues and abutments were embedded in resin blocks. Forty cast crowns were fabricated and divided into 4 groups each containing 10 implants. Group A was cemented directly with the definitive cement (Cem-Implant). The remainder were cemented with provisional cement (Temp-Bond NE), and classified according to the method for cleaning the abutments. Group B used a plastic curette and wet gauze, Group C used a rubber cup and pumice, and Group D used an airborne particle abrasion technique. The abutments were observed using a stereomicroscope after removing the provisional cement. The tensile bond strength was measured after the definitive cementation. Statistical analysis was performed using one-way analysis of variance test (α=.05). RESULTS Group B clearly showed provisional cement remaining, whereas the other groups showed almost no cement. Groups A and B showed a relatively smooth surface. More roughness was observed in Group C, and apparent roughness was noted in Group D. The tensile bond strength tests revealed Group D to have significantly the highest tensile bond strength followed in order by Groups C, A and B. CONCLUSION A plastic curette and wet gauze alone cannot effectively remove the residual provisional cement on the abutment. The definitive retention increased when the abutments were treated with rubber cup/pumice or airborne particle abraded to remove the provisional cement. PMID:24049563

  20. Influence of packing and dispersion of particles on the cement content of concretes

    Directory of Open Access Journals (Sweden)

    B. L. DAMINELI

    Full Text Available Abstract Due to environmental issues, the concrete chain seeks to reduce CO2 emissions. However, growing demand from developing countries causes the increase of CO2 emissions in production to exceed decreases generated by industrial actions, such as improving kilns and clinker replacement. New strategies are important. Changes in the concrete formulation, making it more efficient, can help if these changes produce concrete with the same performance and lower cement consumption. In this regard, the improvement of packing and dispersion of particles increases this efficiency. The better the packing, the lower the volume of voids between particles, thereby requiring lower fluid content (water to permit flow. The dispersion of the particles also decreases the water content for the same fluidity. The less the water content, the smaller the water/cement (w/c ratio, and the greater the resistance. Thus, both strategies increase the efficiency by uncoupling obtaining fluidity from the water content. This study investigated the influence of packing and dispersion on the efficiency of cement use in concrete. The increase of packing and the complete dispersion of fine particles has been shown to improve efficiency, as measured by the ratio between binder consumption and compressive strength (the performance parameter used in most practical applications.