| 1. |
- Al-Khateeb, Susan
(författare)
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Studies on the remineralization of white spot lesions : longitudinal assessment with quantitative light-induced fluorescence
- 1998
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The global aim of this work was to develop and test the light induced fluorescence method using either laser light or a regular, i.e. noncoherent light source for quantification of mineral changes in white spot lesions. Validation studies were carried out to establish the correlation between fluorescence loss and mineral loss. One study was performed to investigate the porosity of white spot lesions of different origins and its effect on the optical characteristics of a white spot lesion. Further, the remineralization process of "open lesions" was studied under different conditions: the effect of acid etching of white spot lesions was investigated in presence or absence of fluoride in an in vitro study. The effect of fluoride supplementation at regularly use of F dentifrice on the remineralization of white spot lesions was investigated in an in situ model. Moreover, the mineral changes in white spot lesions developed in vivo during orthodontic fixed appliance treatment were followed longitudinally. It was concluded that the laser fluorescence method is sensitive and valid for the quantification of mineral loss in natural incipient enamel lesions. Changes in enamel fluorescence reflected changes in mineral content during de- and remineralization processes in the enamel providing the basis for a quantitative method for assessment of mineral changes to a depth of about 450 µm in vitro, in situ, and in vivo. The light induced fluorescence method could operate using monochromatic laser light at the wave length 488 nm, or with a regular (noncoherent) white light source emerging from a Xenon gas-chargeable lamp. Addition of fluoride for the remineralization of "open lesions" caused redistribution of the minerals in the white spot lesions and blockage of their surface layer. In healthy young adults with normal salivary flow and good oral hygiene, fluoride supplementation to the regular use of F dentifrice did not further enhance the remineralization of artificially induced subsurface enamel lesions. Acid etching of white spot lesions enhanced the remineralization process of these lesions. Full remineralization of the so called "open lesions" was not obtained neither in vitro nor in the in vivo environment. Using the QLF method, it would be possible to register the rate of dehydration of a white spot lesion, thus providing information about the nature of that lesion regarding the characteristics of its surface layer.
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| 2. |
- Al-Khatib, A., et al.
(författare)
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Competition between collective and noncollective excitation modes at high spin in Ba-124
- 2006
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 74:1
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Ba-124 were investigated in two experiments using the Ni-64(Ni-64, 4n)Ba-124 reaction at three different beam energies. In-beam gamma-ray coincidences were measured with the Euroball and Gammasphere detector arrays. In the experiment with Euroball, the CsI detector array Diamant was employed to discriminate against charged-particle channels. Six new rotational bands were observed in Ba-124, and previously known bands were extended to higher spins. One of the bands shows a transition from collective to noncollective behavior at high spins. Configuration assignments are suggested on the basis of comparison with cranked shell model and cranked Nilsson-Strutinsky calculations.
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| 3. |
- Al-Khatib, A., et al.
(författare)
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High-spin states in Ba-124
- 2005
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Ingår i: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 36:4, s. 1029-1032
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Ba-124 were populated using the Ni-64 (Ni-64,4n) Ba-124 reaction at beam energies of 255 and 261 MeV. Gamma-ray coincidences were measured using the EUROBALL detector array. The charged-particle detector array DIAMANT provided channel selection. The previously known rotational bands are extended to higher spins. Five new hands are observed, one of them extends up to the spin 40h region.
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| 4. |
- Al-Khatib, Ahmad, 1974
(författare)
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Sabîl
- 2012
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Ingår i: 321090 Institute du Monde Arabe.
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Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- Sabîl (Institut du Monde Arabe 321090) Ahmad joins up with percussionist Youssef Hbeisch on this CD of his own compositions, which includes comprehensive liner notes. 1. Khundî Ma'ak (Take me along) 7:18 2. Sifr El-Khurûj I - Musa (Exode I - Moses) 4:19 3. Sifr El-Khurûj II - Kan'ân (Exode II - Canaan) 1:52 4. Sifr El-Khurûj III - Nahrayn (Exode II - Two Rivers) 4:26 5. Bayyâ' El-Ward (The Rose Vendor) 5:46 6. Li Alix (For Alix) 5:08 7. Maqâm li Ghazzâ (Maqâm for Gaza) 4:39 8. Sabîl (On the Way) 4:39 9. 'Ors (Wedding) 4:37 10. Shadhâ (Fragrance) 4:35 11. Ya Halâlû yâ mâlû (Their Palestine) 5:38
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| 5. |
- Al-Khatib, A, et al.
(författare)
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Transition to non-collective states at high spin in Xe-124
- 2008
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 36:1, s. 21-29
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in Xe-124 were populated in the reaction Se-82(Ca-48, 6n) Xe-124 and gamma-ray coincidence relationships were measured with the Gammasphere spectrometer. Two new bands are observed and several of the previously known bands are extended in the high-as well as in the low-spin region. Two irregular high-spin structures are also added. The irregularities are a fingerprint of a transition from collective to non-collective behaviour. Configuration assignments to the new structures are proposed on the basis of systematics and by comparing experimental properties with calculations within the framework of the cranking model.
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| 6. |
- Anacleto, Pedro, et al.
(författare)
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Precisely nanostructured HfO2 rear passivation layers for ultra-thin Cu(In,Ga)Se-2
- 2022
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Ingår i: Progress in Photovoltaics. - : John Wiley & Sons. - 1062-7995 .- 1099-159X. ; 30:11, s. 1289-1297
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Tidskriftsartikel (refereegranskat)abstract
- The quest for material-efficient Cu(In,Ga)Se-2 (CIGS) solar cells encourages the development of ultra-thin absorbers. Their use reduces material consumption and energy usage during production by increasing the throughput. Thereby, both the bill of materials as well as the energy and capital costs are reduced. However, because thin absorbers are prone to increase back contact recombination, back surface passivation schemes are necessary to reach a similar or higher conversion efficiency than for absorbers with conventional thickness. Here, we investigate nanostructured hafnium oxide (HfO2) rear passivation layers for ultra-thin CIGS solar cells. We fabricate regular arrays of point contacts with 200 nm diameter through HfO2 layers with thicknesses between 7 and 40 nm using electron beam lithography and reactive ion etching. The current-voltage curves of solar cells with a 500 nm thick CIGS absorber layer and the nanostructured passivation layer show improved performance concerning V-oc and J(sc) compared to non-passivated reference devices. Furthermore, external quantum efficiency and optical reflection confirm an effective passivation behavior, with an average efficiency increase of up to 1.2% for the cells with the 40 nm thick HfO2 layer. In addition, simulation work shows that even 40 nm thick HfO2 passivation layers have only a minimal effect on the optical properties of ultra-thin CIGS solar cells, and hence, the photocurrent increase verified experimentally stems from electrical improvements caused by the HfO2 layer passivation effect. We also investigate the impact of ultra-thin (0.3, 0.6, 1.3, and 2.5 nm) non-patterned HfO2 passivation layers on the same type of solar cells. However, these results showed no improvement in solar cell performance, despite an increase in the current density with layer thickness.
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| 7. |
- Badinlou, Farzaneh, et al.
(författare)
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Investigating the trajectory of post-COVID impairments: a longitudinal study in Sweden
- 2024
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Ingår i: FRONTIERS IN PSYCHOLOGY. - : Frontiers Media SA. - 1664-1078. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Individuals recovering from COVID-19 often experience a range of post-recovery symptoms. However, the literature on post-COVID-19 symptoms reveals conflicting results, necessitating a heightened focus on longitudinal studies to comprehend the trajectory of impairments over time. Our study aimed to investigate changes in long-term impairments among individuals infected with COVID-19 and explore potential predictors influencing these changes.Methods We conducted a web-survey targeting individuals that had been infected with COVID-19 at four time-points: T0 (baseline), T1 (three months), T2 (six months), and T3 (twelve months). The survey included contextual factors, factors related to body functions and structures, and post-COVID impairments. The longitudinal sample included 213 individuals (with a mean age of 48.92 years). Linear mixed models were employed to analyze changes in post-COVID impairments over time and identify impacting factors.Results Findings revealed a general decline in post-COVID impairments over time, with each symptom exhibiting a dynamic pattern of fluctuations. Factors such as initial infection severity, education level, and work status were significantly associated with the levels of impairments.Discussion The study emphasizes that post-COVID impairments are not static but exhibit variations over time. Personalized care, especially for vulnerable populations, is crucial. The results underscore the need for long-term monitoring and multidisciplinary treatment approaches. Targeted support and interventions are highlighted for individuals with severe initial infections and those in socioeconomically disadvantaged groups.
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| 8. |
- Bjurenstedt, Anton, 1979-
(författare)
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GRETA – Fallstudie återvunnen aluminium
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- GRETA – a case study on die-cast secondary aluminiumIn ongoing production at AGES in Kulltorp, die-cast components of a secondary aluminium alloy have been continuously taken out for mechanical testing and microstructure investigations. The aim has been to increase the understanding of whether properties vary and, if so, why. In an industrial and well-controlled process, the properties and performance of the obtained material has been analysed for comparison with the original secondary alloy and its specification to see how the material varies during production. The results showed a uniform quality of the produced castings. The hardness test also showed very even results for each component. No statistical difference between the samples could be demonstrated. This means that even if some data collected from the castings were on the edge of the desired range, the properties have not been significantly affected. In other words, there is a higher potential in recycled alloys than that reported in the standard SS-EN 1706:2021. Solidification rate, possible heat treatment and the amount of defects play a decisive role in the final properties of a cast part. By optimizing these, properties that exceed the standard can be obtained.
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| 9. |
- Bjurenstedt, Anton
(författare)
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Imperfections in Recycled Aluminium-Silicon Cast Alloys
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In striving to produce high quality cast components from recycled aluminium alloys,imperfections have to be considered, because recycled aluminium usually containsmore of it. However, there are great energy savings to be made by using recycledaluminium; as little as 5% of the energy needed for primary aluminium productionmay be required. High quality castings are dependent on, besides alloy chemistry, bothmelt quality and the casting process; the focus of this work is related to the meltquality.This thesis aims to increase knowledge about imperfections, foremost about Fe-richparticles, oxides/bifilms, and porosity. Experiments were performed at industrialfoundry facilities and in a laboratory environment. Melt quality was evaluated byproducing samples with the reduced pressure test (RPT), from which both densityindex (DI) and bifilm index (BI) could be measured, results that were related to tensiletest properties. Data from tensile test samples were analysed, and fracture surfacesand cross sections were studied in both light microscope and in scanning electronmicroscope (SEM). For the purpose of investigating nucleation of primary Fe-richparticles (sludge) differential scanning calorimetry (DSC) was used.In the analysis of results, a correlation between the morphology of particles and tensileproperties were found. And elongated Fe-rich β-particles were seen to fracturethrough cleavage towards the centre. However, DI and BI have not been possible torelate to tensile properties.The nucleation temperature of primary Fe-rich particles were found to increase withincreased Fe, Mn, and Cr contents, i.e. the sludge factor (SF), regardless of cooling rate.For a set SF, an increase of cooling rate will decrease the nucleation temperature.
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| 10. |
- Bjurenstedt, Anton, et al.
(författare)
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In-situ study of morphology and growth of primary α-Al(FeMnCr)Si intermetallics in an Al-Si alloy
- 2017
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Ingår i: Acta Materialia. - : Elsevier. - 1359-6454 .- 1873-2453. ; 130, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Morphology and growth of primary α-Al(FeMnCr)Si intermetallics have been studied in-situ during solidification of a commercial secondary aluminum alloy employing X-radiographic imaging combined with deep-etching. The α-Al(FeMnCr)Si intermetallics were found to nucleate primarily on surface oxides, and the continued growth yielded both rhombic dodecahedrons and elongated rod-like morphologies. Both morphologies were observed as hopper and massive types, where the hopper intermetallics had the higher growth rates. The growth rate, which determines the type, appears to be linked to nucleation frequency; higher nucleation frequency promoted massive types and lower nucleation frequency promoted hopper intermetallics.
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