525 research outputs found

    Thermodynamic and economic analysis of a plant for the CO2 hydrogenation for methanol production

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    A major goal of politics, society, and industry is the reduction of carbon dioxide (CO2) emissions in order to prevent anthropogenic climate change and an increase in earth's temperature. In addition, the expansion of renewable energies and the use of nuclear power, CO2 capturing (e.g. from exhaust gases), is regarded as a promising strategy to reduce global CO2 emissions. In this context, the Power-to-X technologies can provide an innovative energy storage concept by combining the main trends of energy systems aiming at high shares of renewable energies, reduction of CO2 emissions and sector coupling. A promising approach is the production of methanol as a chemical raw material or fuel. The goal of this paper is to present (i) an extensive thermodynamic analysis for the methanol production from carbon dioxide and hydrogen and (ii) an economic analysis for the process based on the thermodynamic studies. The thermodynamic analysis was carried out in the simulation tool Aspen Plus™ in order to investigate the impact of the operating temperature and pressure on the performance of the synthesis unit. Based on the thermodynamic results, an economic analysis has been performed in order to define the most feasible solution. For a defined optimal operating temperature, the fixed and operating costs and the methanol production cost were evaluated for different operating pressures. Finally, a sensitivity analysis has been performed in order to define the minimum methanol selling price that allows for a payback period of 10 years for different values of the electrical energy purchasing price

    Auf schwankendem Grund. Dekadenz und Tod im Venedig der Moderne

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    Anlass des Bandes ist das Centenarium von Thomas Manns Novelle "Der Tod in Venedig" (1912), in der Gustav von Aschenbach als ein der historischen Wissenschaft verpflichteter Schriftsteller in unsicheres Terrain jenseits rationaler Begrifflichkeit gerät, ins Sehnsuchtsland der Liebe und des Schönen, und schließlich in einen Grenzbereich, in dem alles Gestaltete ins Gestaltlose und schließlich in den Tod übergeht. Venedig um 1900, die auf Wasser gebaute, einstige Seerepublik in politischer Dekadenz ist nicht zufällig dafür topisch, und Aschenbach mit seinen ethischen, ästhetischen und epistemologischen Erschütterungen in Venedig nicht allein. Venedig prägte seine eigene Moderne aus und wurde als physisch erlebter wie imaginier­ter Ort für Dichter, Maler und Musiker zum Spiegel der Krisenerfahrungen um 1900. Anders gesagt: Die Stadt fungierte als Seismograph, mit dem sich der Verlust metaphysischer Gewissheiten, der Verlust des Vertrauens in die Evidenz des Wissens, in die Einheit der Person und der Zuverlässigkeit der Sprache aufzeichnen ließ. Die Unbestimmtheit, der Kontrollverlust, die der Lagu­nenstadt eigene Bewegung ›auf schwankendem Grund‹ wird bei Thomas Mann und seinen Zeitgenossen zum Motor der Kreativität

    Die Sieben Todsünden

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    Weshalb faszinieren und inspirieren die Sieben Todsünden bis heute – auch und gerade obwohl theologische Kommentare längst an Verbindlichkeit eingebüßt haben? In exemplarischen Studien widmet sich der Sammelband der Wirkungsgeschichte der Sieben Todsünden in den unterschiedlichen Künsten: Literatur und bildende Kunst, Film und Fernsehen. Der Fokus liegt weniger auf einer Ideengeschichte der Todsünden als auf deren Formelhaftigkeit, die gerade im Verblassen der ursprünglichen Hintergründe ihre Wirkmacht in breiter diskursiver Streuung entfaltet. Dabei reichen die vielfältigen Fortschreibungen und Transformationen weit über das frühe Mittelalter und die klassische Theologie hinaus und zeigen in der Moderne und Postmoderne verstärkt nur noch Allusionen auf die ursprünglich religiöse Ordnungsphantasie. So werden die Todsünden zu einem intermedialen Fundus für ethische und politische Reflexionen, ästhetische Transformationen und künstlerische Experimente. Der Band versammelt Studien, die sich aus literatur-, medien- und kulturwissenschaftlicher Perspektive sowohl den einzelnen Todsünden superbia, invidia, ira, acedia, avaritia, gula, luxuria als auch dem Septenar insgesamt widmen

    Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

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    This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

    Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

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    One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

    Severe early onset preeclampsia: short and long term clinical, psychosocial and biochemical aspects

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    Preeclampsia is a pregnancy specific disorder commonly defined as de novo hypertension and proteinuria after 20 weeks gestational age. It occurs in approximately 3-5% of pregnancies and it is still a major cause of both foetal and maternal morbidity and mortality worldwide1. As extensive research has not yet elucidated the aetiology of preeclampsia, there are no rational preventive or therapeutic interventions available. The only rational treatment is delivery, which benefits the mother but is not in the interest of the foetus, if remote from term. Early onset preeclampsia (<32 weeks’ gestational age) occurs in less than 1% of pregnancies. It is, however often associated with maternal morbidity as the risk of progression to severe maternal disease is inversely related with gestational age at onset2. Resulting prematurity is therefore the main cause of neonatal mortality and morbidity in patients with severe preeclampsia3. Although the discussion is ongoing, perinatal survival is suggested to be increased in patients with preterm preeclampsia by expectant, non-interventional management. This temporising treatment option to lengthen pregnancy includes the use of antihypertensive medication to control hypertension, magnesium sulphate to prevent eclampsia and corticosteroids to enhance foetal lung maturity4. With optimal maternal haemodynamic status and reassuring foetal condition this results on average in an extension of 2 weeks. Prolongation of these pregnancies is a great challenge for clinicians to balance between potential maternal risks on one the eve hand and possible foetal benefits on the other. Clinical controversies regarding prolongation of preterm preeclamptic pregnancies still exist – also taking into account that preeclampsia is the leading cause of maternal mortality in the Netherlands5 - a debate which is even more pronounced in very preterm pregnancies with questionable foetal viability6-9. Do maternal risks of prolongation of these very early pregnancies outweigh the chances of neonatal survival? Counselling of women with very early onset preeclampsia not only comprises of knowledge of the outcome of those particular pregnancies, but also knowledge of outcomes of future pregnancies of these women is of major clinical importance. This thesis opens with a review of the literature on identifiable risk factors of preeclampsia

    Search for stop and higgsino production using diphoton Higgs boson decays

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    Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top-quark (stop) and the Higgs boson (higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7 inverse femtobarns of proton-proton collision data at sqrt(s) = 8 TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the stop mass below 360 to 410 GeV, depending on the higgsino mass

    Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

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    The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe
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