| 553341. |
- Lindberg, Anna, et al.
(författare)
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Selective desorption of carbon dioxide from sewage sludge for in situ methane enrichment - Part 1 : Pilot-plant experiments
- 2006
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Ingår i: Biotechnology and Bioengineering. - : Wiley. - 0006-3592 .- 1097-0290. ; 95:5, s. 794-803
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Tidskriftsartikel (refereegranskat)abstract
- In situ methane enrichment in anaerobic digestion of sewage sludge has been investigated by experiments and by modeling. In this first part, the experimental work on the desorption of carbon dioxide and methane from sewage sludge is reported. The bubble column, had a diameter of 0.3 m and a variable height up to 1.8 m. At operation the dispersion height in the column was between 1 and 1.3 m. Outdoor air was used. The column was placed close to a full-scale sewage sludge digester, at a municipal wastewater treatment plant. The digester was operated at mesophilic conditions with a hydraulic retention time of about 20 days. The bubble column was operated to steady-state, at which carbon dioxide concentration and alkalinity were determined on the liquid side, and the concentration of carbon dioxide and methane on the gas side. Thirty-eight experiments were performed at various liquid and gas flow rates. The experimental results show that the desorption rates achieved for carbon dioxide ranges from 0.07 to 0.25 m(3) CO2/m(3) sludge per day, which is comparable to the rate of generation by the anaerobic digestion. With increasing liquid flow rate and decreasing gas flow rate the amount of methane desorbed per amount of carbon dioxide desorbed increases. The lowest methane loss achieved is approximately 2% of the estimated methane production in the digestion process.
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| 553342. |
- Lindberg, Anna, et al.
(författare)
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Selective desorption of carbon dioxide from sewage sludge for in situ methane enrichment - Part II : Modelling and evaluation of experiments
- 2007
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Ingår i: Biotechnology and Bioengineering. - : Wiley. - 0006-3592 .- 1097-0290. ; 97:5, s. 1039-1052
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Tidskriftsartikel (refereegranskat)abstract
- In situ methane enrichment in anaerobic digestion of sewage sludge has been investigated by experiments and by modelling. Sludge from a full scale digester was fed to a pilot scale bubble column having 0.3 m diameter for preferential desorption of carbon dioxide. In this second part, a model describing the steady-state performance of the bubble column for desorption of carbon dioxide and methane has been developed. The column is assumed to operate in the homogeneous flow regime, and with respect to carbon dioxide and methane both phases are described by the axial dispersion model.. The model treats the chemical reaction equilibrium between carbon dioxide and bicarbonate as being slow and the bicarbonate concentration as being constant. The model is correlated to previously reported experimental, results to determine the liquid side mass transfer coefficient in each experiment. A simple power law model is used to correlate, the mass transfer coefficient to the gas flow rate. In general, the model allows for a reasonable qualitative description of the behaviour of the bubble column performance but the quantitative agreement with experimental results is not satisfactory. It is believed, though that the main. problem is actually not in the model but is related to experimental uncertainties concerning inlet concerttrations of liquid phase methane and bicarbonate..
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| 553343. |
- Lindberg, Anne, et al.
(författare)
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Seven-year cumulative incidence of COPD in an age-stratified general population sample.
- 2006
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Ingår i: Chest. - : Elsevier BV. - 0012-3692 .- 1931-3543. ; 129:4, s. 879-885
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To estimate the cumulative incidence of COPD and risk factors related to the development of COPD, including evaluation of the relationship between Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 0 (ie, respiratory symptoms and normal lung function) and the development of COPD, in an age-stratified general population sample of middle-aged and elderly individuals. METHOD: The third survey of the Obstructive Lung Disease in Northern Sweden studies cohort I (three age strata born in 1919 to 1920, 1934 to 1935, and 1949 to 1950) was performed in 1996, and 5,189 subjects (88%) responded to the postal questionnaire. Of the responders, a random sample (1,500 subjects) was invited to an examination in 1996 and in 2003. A total of 963 subjects performed spirometry on both occasions. COPD was defined according to the spirometric criteria of the GOLD. Two levels of disease severity, grade I and higher (GOLD criteria, FEV(1)/FVC ratio of < 0.70) and also grade II and higher (GOLD II criteria, FEV(1)/FVC ratio of < 0.70 and FEV(1) <80% predicted). RESULTS: The 7-year cumulative incidence of COPD was 11.0% and 4.9%, respectively, according to GOLD and GOLD II, and was significantly related to smoking (smokers, 18.8% and 10.6%, respectively; ex-smokers, 10.5% and 5.2%, respectively; non-smokers, 7.6% and 1.6%, respectively). Incident COPD according to GOLD, but not according to GOLD II, was significantly associated with increasing age. Most respiratory symptoms at study entry were markers of increased risk for incident COPD when analyzed in a multivariate model adjusting for confounders. CONCLUSION: The GOLD criteria yielded a higher cumulative incidence (11.0%) compared to the GOLD II (4.9%). Smoking, but not gender, was associated with incident COPD. Most respiratory symptoms at the beginning of the observation period marked an increased risk for developing COPD, thus the classification GOLD stage 0 seems relevant among middle-aged and elderly persons.
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| 553344. |
- Lindberg, Aleksandra, 1990-, et al.
(författare)
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Sources of Oxygen Produced in the Chlorate Process Utilizing Dimensionally Stable Anode (DSA) Electrodes Doped by Sn and Sb
- 2021
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Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 60:37, s. 13505-13514
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Tidskriftsartikel (refereegranskat)abstract
- Identifying the sources of oxygen in the chlorate process is challenging due to the complex set of chemical and electrochemical reactions involved. Here, two types of electrodes have been investigated-Ti0.7Ru0.3Ox, and electrodes with aimed composition Ti0.34Ru0.3Sn0.3Sb0.06Ox, both compared with platinum anodes. The cell oxygen off-gas was analyzed employing mass spectrometry together with ex situ UV-vis spectroscopy to quantify the kinetic rate constants. Noteworthy is that the respective rates of oxygen formation from anodic and chemical reactions in the presence of hypochlorite are of the same magnitude. The addition of Sn and Sb doubled the surface area of the electrodes and decreased oxygen production when electrodes were used for the first time. However, rate constants for total oxygen production with reused electrodes follow the trend: homogeneous hypochlorite decomposition < TiRu < TiRuSnSb to the highest value obtained by Pt. The same trend is noticed for rate constants concerning the hypochlorite decomposition.
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| 553345. |
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| 553346. |
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| 553347. |
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| 553348. |
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| 553349. |
- Lindberg, Anne, et al.
(författare)
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Subjects with COPD and productive cough have an increased risk for exacerbations and death
- 2015
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Ingår i: Respiratory Medicine. - : Elsevier BV. - 0954-6111 .- 1532-3064. ; 109:1, s. 88-95
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Tidskriftsartikel (refereegranskat)abstract
- Background: Chronic bronchitis is related to worse general health status, exacerbations and mortality among subjects with COPD. Also less longstanding cough and phlegm may be related to worse prognosis in COPD but this has rarely been evaluated in population-based studies. Aim: To evaluate the relationship between productive cough, exacerbations and mortality among subjects with and without COPD. Method: All subjects with COPD (n = 993) were identified together with sex-and age matched reference subjects without obstructive lung function impairment from four population-based cohorts in 2002-04. Baseline spirometry and structured interview including data on exacerbations last 12 months were used in this study (n = 1986) together with mortality data collected until February 2012. Results: Productive cough was more common in COPD than non-COPD (42.8 vs. 23.5%, p < 0.001), more common in men than women, but associated to exacerbations in both sexes. COPD-subjects with productive cough had the highest risk for exacerbations in both sexes and they had a significantly increased risk for death (HR 1.48, 95% CI 1.13-1.94) also when adjusted for sex, age, BMI, smoking habits and heart disease. Conclusion: Productive cough was common and increased the risk for exacerbations in both sexes, in both COPD and non-COPD. COPD-subjects with productive cough had the highest risk for exacerbations and a significantly higher risk for death also after adjustment for common risk factors. (C) 2014 Elsevier Ltd. All rights reserved.
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| 553350. |
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