418 research outputs found

    The Effect of Atomic Layer Deposited Overcoat on Co-Pt-Si/γ-Al2O3 Fischer–Tropsch Catalyst

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    Atomic layer deposition (ALD) was used to prepare a thin alumina layer on Fischer–Tropsch catalysts. Co-Pt-Si/γ-Al2O3 catalyst was overcoated with 15–40 cycles of Al2O3 deposited from trimethylaluminum (TMA) and water vapor, followed by thermal annealing. The resulting tailored Fischer–Tropsch catalyst with 35 cycle ALD overcoating had increased activity compared to unmodified catalyst. The increase in activity was achieved without significant loss of selectivity towards heavier hydrocarbons. Altered catalyst properties were assumed to result from cobalt particle stabilization by ALD alumina overcoating and nanoscale porosity of the overcoating. In addition to optimal thickness of the overcoat, thermal annealing was an essential part of preparing ALD overcoated catalyst

    The Effect of Atomic Layer Deposited Overcoat on Co-Pt-Si/γ-Al2O3 Fischer–Tropsch Catalyst

    Get PDF
    Atomic layer deposition (ALD) was used to prepare a thin alumina layer on Fischer-Tropsch catalysts. Co-Pt-Si/gamma-Al2O3 catalyst was overcoated with 15-40 cycles of Al2O3 deposited from trimethylaluminum (TMA) and water vapor, followed by thermal annealing. The resulting tailored Fischer-Tropsch catalyst with 35 cycle ALD overcoating had increased activity compared to unmodified catalyst. The increase in activity was achieved without significant loss of selectivity towards heavier hydrocarbons. Altered catalyst properties were assumed to result from cobalt particle stabilization by ALD alumina overcoating and nanoscale porosity of the overcoating. In addition to optimal thickness of the overcoat, thermal annealing was an essential part of preparing ALD overcoated catalyst.Peer reviewe

    The Effect of Atomic Layer Deposited Overcoat on Co-Pt-Si/γ-Al2O3 Fischer–Tropsch Catalyst

    Get PDF
    Atomic layer deposition (ALD) was used to prepare a thin alumina layer on Fischer–Tropsch catalysts. Co-Pt-Si/γ-Al2O3 catalyst was overcoated with 15–40 cycles of Al2O3 deposited from trimethylaluminum (TMA) and water vapor, followed by thermal annealing. The resulting tailored Fischer–Tropsch catalyst with 35 cycle ALD overcoating had increased activity compared to unmodified catalyst. The increase in activity was achieved without significant loss of selectivity towards heavier hydrocarbons. Altered catalyst properties were assumed to result from cobalt particle stabilization by ALD alumina overcoating and nanoscale porosity of the overcoating. In addition to optimal thickness of the overcoat, thermal annealing was an essential part of preparing ALD overcoated catalyst

    Predictors of hospital and one-year mortality in intensive care patients with refractory status epilepticus : a populationbased study

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    Background: The aim was to determine predictors of hospital and 1-year mortality in patients with intensive care unit (ICU)-treated refractory status epilepticus (RSE) in a population-based study. Methods: This was a retrospective study of the Finnish Intensive Care Consortium (FICC) database of adult patients (16 years of age or older) with ICU-treated RSE in Finland during a 3-year period (2010-2012). The database consists of admissions to all 20 Finnish hospitals treating RSE in the ICU. All five university hospitals and 11 out of 15 central hospitals participated in the present study. The total adult referral population in the study hospitals was 3.92 million, representing 91% of the adult population of Finland. Patients whose condition had a post-anoxic aetiological basis were excluded. Results: We identified 395 patients with ICU-treated RSE, corresponding to an annual incidence of 3.4/100,000 (95% confidence interval (CI) 3.04-3.71). Hospital mortality was 7.4% (95% CI 0-16.9%), and 1-year mortality was 25. 4% (95% CI 21.2-29.8%). Mortality at hospital discharge was associated with severity of organ dysfunction. Mortality at 1 year was associated with older age (adjusted odds ratio (aOR) 1.033, 95% CI 1.104-1.051, p = 0.001), sequential organ failure assessment (SOFA) score (aOR 1.156, CI 1.051-1.271, p = 0.003), super-refractory status epilepticus (SRSE) (aOR 2.215, 95% CI 1.20-3.84, p = 0.010) and dependence in activities of daily living (ADL) (aOR 2.553, 95% CI 1.537-4.243, p <0.0001). Conclusions: Despite low hospital mortality, 25% of ICU-treated RSE patients die within a year. Super-refractoriness, dependence in ADL functions, severity of organ dysfunction at ICU admission and older age predict long-term mortality.Peer reviewe

    Premorbid functional status as an outcome predictor in intensive care patients aged over 85 years

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    Background Poor premorbid functional status (PFS) is associated with mortality after intensive care unit (ICU) admission in patients aged 80 years or older. In the subgroup of very old ICU patients, the ability to recover from critical illness varies irrespective of age. To assess the predictive ability of PFS also among the patients aged 85 or older we set out the current study. Methods In this nationwide observational registry study based on the Finnish Intensive Care Consortium database, we analysed data of patients aged 85 years or over treated in ICUs between May 2012 and December 2015. We defined PFS as good for patients who had been independent in activities of daily living (ADL) and able to climb stairs and as poor for those who were dependent on help or unable to climb stairs. To assess patients' functional outcome one year after ICU admission, we created a functional status score (FSS) based on how many out of five physical activities (getting out of bed, moving indoors, dressing, climbing stairs, and walking 400 m) the patient could manage. We also assessed the patients' ability to return to their previous type of accommodation. Results Overall, 2037 (3.3% of all adult ICU patients) patients were 85 years old or older. The average age of the study population was 87 years. Data on PFS were available for 1446 (71.0%) patients (good for 48.8% and poor for 51.2%). The one-year mortalities of patients with good and those with poor PFS were 29.2% and 50.1%, respectively, p < 0.001. Poor PFS increased the probability of death within 12 months, adjusted odds ratio (OR), 2.15; 95% confidence interval (CI) 1.68-2.76, p < 0.001. For 69.5% of survivors, the FSS one year after ICU admission was unchanged or higher than their premorbid FSS and 84.2% of patients living at home before ICU admission still lived at home. Conclusions Poor PFS doubled the odds of death within one year. For most survivors, functional status was comparable to the premorbid status.Peer reviewe

    Pure aromatics from biomass

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    Temporal Trends in Healthcare Costs and Outcome Following ICU Admission After Traumatic Brain Injury

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    Objective: To assess temporal trends in 1-year healthcare costs and outcome of intensive care for traumatic brain injury in Finland. Design: Retrospective observational cohort study. Setting: Multicenter study including four tertiary ICUs. Patients: Three thousand fifty-one adult patients (>= 18 yr) with significant traumatic brain injury treated in a tertiary ICU during 2003-2013. Intervention: None. Measurements and Main Results: Total 1-year healthcare costs included the index hospitalization costs, rehabilitation unit costs, and social security reimbursements. All costs are reported as 2013 U.S. dollars ().Outcomeswere1yearmortalityandpermanentdisability.Multivariateregressionmodels,adjustingforcasemix,wereusedtoassesstemporaltrendsincostsandoutcomeinpredefinedGlasgowComaScale(38,912,and1315)andage(1840,4164,and>=65yr)subgroups.Overall1yearsurvivalwas76). Outcomes were 1-year mortality and permanent disability. Multivariate regression models, adjusting for case-mix, were used to assess temporal trends in costs and outcome in predefined Glasgow Coma Scale (3-8, 9-12, and 13-15) and age (18-40, 41-64, and >= 65 yr) subgroups. Overall 1-year survival was 76% (n = 2,304), and of 1-year survivors, 37% (n = 850) were permanently disabled. Mean unadjusted 1-year healthcare cost was 39,809 (95% CI, 38,14438,144-41,473) per patient. Adjusted healthcare costs decreased only in the Glasgow Coma Scale 13-15 and 65 years and older subgroups, due to lower rehabilitation costs. Adjusted 1-year mortality did not change in any subgroup (p <0.05 for all subgroups). Adjusted risk of permanent disability decreased significantly in all subgroups (p <0.05). Conclusion: During the last decade, healthcare costs of ICU-admitted traumatic brain injury patients have remained largely the same in Finland. No change in mortality was noted, but the risk for permanent disability decreased significantly. Thus, our results suggest that cost-effectiveness of traumatic brain injury care has improved during the past decade in Finland.Peer reviewe

    Production of C₂ −C₄ Olefins with Fischer‐Tropsch‐Synthesis: The Effect of Cu Promoter Loading on an Fe−Cu−K/SiO₂ Catalyst

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    In this study we focus on the iron-based catalyst to produce C2−C4 olefin hydrocarbons via the high-temperature Fischer-Tropsch synthesis. Promoters have a significant impact on catalyst stability, activity, and product selectivity. Therefore, we investigated the effect of the Cu promoter in an Fe−Cu−K/SiO2 catalyst. We compared the catalyst without Cu and 1, 2, 3, 4, and 5 wt % Cu loadings. The overall catalyst activity increased from 0 to 3 wt % Cu loading and started to decrease at 4 and 5 wt % Cu loadings. Although overall catalyst activity had an optimum with 3 and 4 wt % Cu loading, the Cu loading had a negligible effect on product selectivity. However, when compared to a non-Cu promoted catalyst, the Cu addition increased the selectivity towards olefinic C2−C4 hydrocarbons. The Fischer-Tropsch experiments were performed in a tubular reactor system at 300 °C, 21 bar and H2 : CO=2 at different feed volume flows, with hydrogen activation. According to the performed temperature-programmed dynamic chemisorption analysis, the Cu promoter assisted the iron reduction, and the lower overall activity to 0–2 wt % Cu loading might relate to insufficient dissociated H surface species, rather than the availability of C from dissociated CO
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