| 1. |
- Ahmad, Waqar, et al.
(författare)
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Investigation of different configurations of alumina packed bed reactor for coke free conversion of benzene
- 2024
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Ingår i: Chemical engineering research & design. - : Elsevier. - 0263-8762 .- 1744-3563. ; 201, s. 433-445
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Tidskriftsartikel (refereegranskat)abstract
- Conversion of producer gas tar without coke generation is a great challenge. This study investigates conversion of tar model benzene using different configurations of highly non-porous ɣ-Al2O3 packed bed reactor at 1000–1100 0C. The configurations comprised of different positions (relative to top (P1), center (P2) and bottom (P3) of reactor furnace), heights (5, 13 and 25 cm) and particles sizes (0.5, 3 and 5 mm) of alumina packed bed. Steam and CO2 were used as reforming media for tested benzene concentrations (0.4–1.8 vol%). The results showed benzene conversions of 48–91% with negligible steady thin coke generation using a packed bed (height: 25 cm, particles size: 3 mm) at P1. Whereas, relative high benzene conversions of 63–93 and 68–95% at P2 and P3 respectively with unsteady thick coke generation at benzene concentrations greater than 0.4 vol% increased differential upstream pressures (DUPs) of beds. Similar unsteady coke generation at benzene concentrations greater than 0.8 vol% and temperature of 1100 0C was observed with packed beds of heights of 5 and 13 cm, and particles size of 0.5 mm at P1. Generation of unsteady coke with condensed structure as evidenced by its characterization was attributable to increased benzene polymerization and reduced bed surface gasification reactions due to improperly installed packed bed. Developed kinetic model predicted well the generated coke. As conclusion, properly installed alumina packed bed pertaining to tar concentration and other experimental conditions may inhibit coke generation during tar conversion.
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| 2. |
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| 3. |
- Belova, Alla, et al.
(författare)
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Planetary waves in ozone and temperature in the Northern hemisphere winter of 2002-2003 by Odin satellite data
- 2009
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Ingår i: Annales Geophysicae. - : Copernicus publications. - 0992-7689 .- 1432-0576. ; 27, s. 1189-1206
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Tidskriftsartikel (refereegranskat)abstract
- Temperature and ozone data from the sub-millimetre radiometer (SMR) installed aboard the Odin satellite have been examined to study the relationship between temperature and ozone concentration in the lower and upper stratosphere in winter time. The retrieved ozone and temperature profiles have been considered between the range of 24–46 km during the Northern Hemisphere (NH) winter of December 2002 to March 2003 and January to March 2005. A comparison between the ozone mixing ratio and temperature fields has been made for the zonal means, wavenumber one variations and 5-day planetary waves. The amplitude values in temperature variations are ~5 K in the wavenumber one and 0.5–1 K in the 5-day wave. In ozone mixing ratio, the amplitudes reach ~0.5 ppmv in the wavenumber one and 0.05–0.1 ppmv in the 5-day wave. Several stratospheric warming events were observed during the NH winters of 2002/2003 and early 2005. Along with these warming events, amplification of the amplitude has been detected in wavenumber one (up to 30 K in temperature and 1.25 ppmv in ozone) and partly in the 5-day perturbation (up to 2 K in temperature and 0.2 ppmv in ozone). In general, the results show the expected in-phase behavior between the temperature and ozone fields in the lower stratosphere due to dynamic effects, and an out-of-phase pattern in the upper stratosphere, which is expected as a result of photochemical effects. However, these relationships are not valid for zonal means and wavenumber one components when the wave amplitudes are changing dramatically during the strongest stratospheric warming event (at the end of December 2002/beginning of January 2003). Also, for several shorter intervals, the 5-day perturbations in ozone and temperature are not well-correlated at lower heights, particularly when conditions change rapidly. Odin's basic observation schedule provides stratosphere mode data every third day and to validate the reliability of the 5-day waves extracted from the Odin measurements, additional independent data have been analysed in this study: temperature assimilation data by the European Centre for Medium-range Weather Forecasts (ECMWF) for the NH winter of 2002/2003, and satellite measurements of temperature and ozone by the Microwave Limb Sounder (MLS) on board the Aura satellite for the NH winter in early 2005. Good agreement between the temperature fields from Odin and ECMWF data is found at middle latitude where, in general, the 5-day perturbations from the two data sets coincide in both phase and amplitude throughout the examined interval. Analysis of the wavenumber one and the 5-day wave perturbations in temperature and ozone fields from Odin and from Aura demonstrates that, for the largest part of the examined period, quite similar characteristics are found in the spatial and temporal domain, with slightly larger amplitude values seen by Aura. Hence, the comparison between the Odin data, sampled each third day, and daily data from Aura and the ECMWF shows that the Odin data are sufficiently reliable to estimate the properties of the 5-day oscillations, at least for the locations and time intervals with strong wave activity.
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| 4. |
- Chanda Chiseni, Michael
(författare)
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Here I am Send Me : The Historical and Long-Term Impact of Christian Missionaries in Zambia 1924-2018
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Towards the close of the nineteenth century and into the twentieth century, there was a proliferation of Christian missionaries in Africa. Upon settling in Africa, missionaries initiated and became the main providers of Western-styled education and health care. For this reason, the historical and enduring impact of missionaries in Africa cannot be overlooked. This thesis examines the synchronic and diachronic impacts of missionary investments in these two key aspects of human capital development on educational and health outcomes in Zambia. To this end, I build historical and contemporary spatial datasets that allow me to analyse the expansion of the missionary enterprise, the development of education and health care systems, and the long-term impact of missionary exposure on educational and health outcomes in Zambia. The findings of this thesis show that various economic, geographical, and agricultural factors influenced the rate of missionary expansion in Zambia. Moreover, although the development of missionary education in Zambia was slow and uneven across gender lines, throughout the colonial period, medical missionaries made great strides towards meeting the medical needs of the majority of the African population with the help of autochthonous auxiliaries. Further, the thesis finds that the historical exposure to missionaries has continued to significantly impact both education and health outcomes in Zambia.
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| 5. |
- Chanda Chiseni, Michael
(författare)
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The sins of the church: The long-term impacts of Christian missionary praxis on HIV and sexual behaviour in Zambia
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Ingår i: Economic History of Developing Regions. - 2078-0397.
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Tidskriftsartikel (refereegranskat)abstract
- This study examines the long-term effect of Christian missionary exposure on HIV infection and related sexual behaviour in Zambia. I use distance to a historical missionary church and health facility as proxies for missionary exposure. I constructed a geocoded data set combining information on the historical locations of churches and missionary health centres with contemporary individual-level data. I find that individuals who live close to a historical missionary church have a higher likelihood of being infected with HIV. I find no significant effect of proximity to a missionary health centre on HIV. Considering that heterosexual transmission is the main channel of HIV transmission in Zambia, I analyse the effect of missionary exposure on sexual behaviour. The following patterns emerge: individuals who live close to a Protestant church are less likely to engage in premarital sexual abstinence; they also have their first sexual encounter at an earlier age, with the effect being stronger for men than women. Living near a Catholic church is associated with having a higher number of sexual partners.
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| 6. |
- Couto, Rafael Carvalho, et al.
(författare)
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Breaking inversion symmetry by protonation : Experimental and theoretical NEXAFS study of the diazynium ion, N2H
- 2021
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 23:32, s. 17166-17176
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Tidskriftsartikel (refereegranskat)abstract
- As an example of symmetry breaking in NEXAFS spectra of protonated species we present a high resolution NEXAFS spectrum of protonated dinitrogen, the diazynium ion N2H+. By ab initio calculations we show that the spectrum consists of a superposition of two nitrogen 1s absorption spectra, each including a π∗ band, and a nitrogen 1s to H+ charge transfer band followed by a weak irregular progression of high energy excitations. Calculations also show that, as an effect of symmetry breaking by protonation, the π∗ transitions are separated by 0.23 eV, only slightly exceeding the difference in the corresponding dark (symmetry forbidden) and bright (symmetry allowed) core excitations of neutral N2. By DFT and calculations and vibrational analysis, the complex π∗ excitation band of N2H+ is understood as due to the superposition of the significantly different vibrational progressions of excitations from terminal and central nitrogen atoms, both leading to bent final state geometries. We also show computationally that the electronic structure of the charge transfer excitation smoothly depends on the nitrogen-proton distance and that there is a clear extension of the spectra going from infinity to close nitrogen-proton distance where fine structures show some, although not fully detailed, similarities. An interesting feature of partial localization of the nitrogen core orbitals, with a strong, non-monotonous, variation with nitrogen-proton distance could be highlighted. Specific effects could be unraveled when comparing molecular cation NEXAFS spectra, as represented by recently recorded spectra of N2+ and CO+, and spectra of protonated molecules as represented here by the N2H+ ion. Both types containing rich physical effects not represented in NEXAFS of neutral molecules because of the positive charge, whereas protonation also breaks the symmetry. The effect of the protonation on dinitrogen can be separated in charge, which extends the high-energy part of the spectrum, and symmetry-breaking, which is most clearly seen in the low-energy π∗ transition.
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| 7. |
- Dillström, Sibylle
(författare)
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Motiviertheit in der Wortbildung entlehnter Einheiten : Eine deskriptive Studie von Personenbezeichnungen mit Fremdsuffixen im Deutschen vom 16. bis zum 20. Jahrhundert
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis looks from a historical perspective at the morphological-semantic motivation of words denoting persons with foreign suffixes that have been borrowed into and also formed in German, whereby, among other things, the role of motivation in relation to the borrowing and retention of lexical items is elucidated.In a theoretical section peculiarities and problems in the word formation of loan items are discussed, and motivation is defined as a synchronous-semantic category. In the analysis words denoting persons that have seven different foreign suffixes, deriving principally from Latin, are examined with material primarily from dictionaries.The study shows that especially for the frequent suffixes in German there is a consistently large proportion of motivated words. It is generally the case that the words are motivated on their first appearance in the material, and changes in their motivation are on the whole infrequent. The analysis further proves that motivated formations often disappear from the material, and words are mostly retained after the loss of their motivation.The reason that the words for the most part are motivated in German when borrowed, is that suffixed words denoting persons are generally closely related in their semantic structure to another word in the original or donor language. In German, a relatively large proportion of motivated formations for one suffix does not always correlate with high frequency or with high productivity of the suffix. Furthermore, many of the words examined do not belong to the common vocabulary, which restricts their motivation from a socio-linguistic point of view and can to some extent contribute to their disappearance.
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| 8. |
- Fellström, Claes
(författare)
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A review of methods used for studying the molecular epidemiology of Brachyspira hyodysenteriae
- 2017
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Ingår i: Veterinary Microbiology. - : Elsevier BV. - 0378-1135 .- 1873-2542. ; 207, s. 181-194
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Forskningsöversikt (refereegranskat)abstract
- Brachyspira (B.) spp. are intestinal spirochaetes isolated from pigs, other mammals, birds and humans. In pigs, seven Brachyspira spp. have been described, i.e. B. hyodysenteriae, B. pilosicoli, B. intermedia, B. murdochii, B. innocens, B. suanatina and B. hampsonii. Brachyspira hyodysenteriae is especially relevant in pigs as it causes swine dysentery and hence considerable economic losses to the pig industry. Furthermore, reduced susceptibility of B. hyodysenteriae to antimicrobials is of increasing concern. The epidemiology of B. hyodysenteriae infections is only partially understood, but different methods for detection, identification and typing have supported recent improvements in knowledge and understanding. In the last years, molecular methods have been increasingly used. Molecular epidemiology links molecular biology with epidemiology, offering unique opportunities to advance the study of diseases. This review is based on papers published in the field of epidemiology and molecular epidemiology of B. hyodysenteriae in pigs. Electronic databases were screened for potentially relevant papers using title and abstract and finally, Barcellos et al. papers were systemically selected and assessed. The review summarises briefly the current knowledge on B. hyodysenteriae epidemiology and elaborates on molecular typing techniques available.Results of the studies are compared and gaps in the knowledge are addressed. Finally, potential areas for future research are proposed.
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| 9. |
- Georgantzi, Kleopatra, 1971-
(författare)
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On the Diagnostics of Neuroblastoma : Clinical and Experimental Studies
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Neuroblastoma (NB) is one of the most common childhood cancers. Patients with low stage tumor have high survival rate, while those with advanced stage and/or unfavorable molecular biology have poor prognosis. A correct histopathological diagnosis, clinical stage, and identified genetic aberrations are crucial for treatment stratification according to current protocol. The tumor sample is obtained either by fine needle aspiration, cutting needle biopsy or open biopsy. NB exhibits neuroendocrine differentiation by showing immunoreactivity for chromogranin A (CgA), synaptophysin (syn), and neuron specific enolase (NSE) and 90% of the patients have increased levels of urine catecholamine metabolites.Experimental and clinical NB tumor samples were immunostained for somatostatin receptors (SSTRs) 1-5, somatostatin and CgA. Clinical tumor samples were also immunostained for syn, synaptic vesicle protein 2 (SV2), and vesicle monoamine transporter 1 (VMAT1) and 2 (VMAT 2). Blood samples from 92 patients were analyzed for level of CgA, NSE, and chromogranin B and compared with control groups. The urinary excretion of catecholamine metabolites was analyzed in samples collected at diagnosis. Clinical and laboratory data were extracted from patient records, including information on the diagnostic accuracy of ultrasound guided cutting needle biopsies (UCNB) and potential complications.We found that NB expressed the different SSTRs and that receptor 2 was the most frequently expressed before chemotherapy. Furthermore, NB tumors showed immunoreactivity for SV2, VMAT 1 and VMAT2 alongside CgA and syn. The immunoreactivity of SV2 was comparable to CgA and superior to syn. Patients with NB had higher blood concentrations of CgA and NSE compared with controls. Patients with advanced stage disease, MYCN amplification and 1 p deletion had higher concentrations of both CgA and NSE while only NSE was correlated to outcome with higher concentrations in the deceased patients.A high urinary excretion of homovanillic acid and dopamine were correlated to inferior outcome. UCNB were found to be safe and may provide all necessary diagnostic requirements for adequate therapy stratification according to current treatment protocols.
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| 10. |
- Hedblom, Marcus, et al.
(författare)
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What is landscape?
- 2015
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Ingår i: Innovative tools to support cooperation among stakeholders in Baltic landscapes : a handbook. - 9789157693600 ; , s. 16-17
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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