| 1. |
- Choularton, T. W., et al.
(författare)
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The Great Dun Fell Cloud Experiment 1993 : An overview
- 1997
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Ingår i: Atmospheric Environment. - 1352-2310. ; 31:16, s. 2393-2405
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Tidskriftsartikel (refereegranskat)abstract
- The 1993 Ground-based Cloud Experiment on Great Dun Fell used a wide range of measurements of trace gases, aerosol particles and cloud droplets at five sites to study their sources and sinks especially those in cloud. These measurements have been interpreted using a variety of models. The conclusions add to our knowledge of air pollution, acidification of the atmosphere and the ground, eutrophication and climate change. The experiment is designed to use the hill cap cloud as a flow-through reactor, and was conducted in varying levels of pollution typical of much of the rural temperate continental northern hemisphere in spring-time.
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| 2. |
- Beckers, M., et al.
(författare)
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Nucleation and growth of Ti2 AlN thin films deposited by reactive magnetron sputtering onto MgO(111)
- 2007
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 102:7
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Tidskriftsartikel (refereegranskat)abstract
- The nucleation and growth of Ti2 AlN thin films on MgO(111) substrates during dual direct current reactive magnetron cosputtering from Ti and Al targets in an Ar N2 atmosphere at a substrate temperature of 690 °C have been investigated. Time and thickness dependent in situ specular x-ray reflectivity and x-ray diffraction in combination with cross-sectional transmission electron microscopy and Rutherford backscattering spectroscopy reveal the formation of competing phases for slight N superstoichiometry with respect to Ti2 AlN. The stoichiometry deviations initiate the layer-by-layer growth of a ∼380 Å thick epitaxial N-substoichiometric cubic (Ti1-x Alx) Ny layer. N-vacancy driven diffusion of Ti and Al leads to decomposition of this metastable solid solution into nanosized cubic TiN y′ and AlN y″ domains as well as to a solid-state reaction with the MgO(111) by formation of a Mg2 (Al:Ti) O4 spinel, reducing the transformed (Ti1-x Alx) Ny layer thickness down to ∼60 Å. Local AlN y″ domains serve as templates for Ti2 AlN nucleation at higher thicknesses. At the same time TiN y′ and AlN y″ serve as a sink for excess gas phase N during the subsequent polycrystalline Ti2 AlN growth with random (Ti1-x Alx) Ny renucleation as a tissue phase along Ti2 AlN grain boundaries. The individual Ti2 AlN grains with vertical sizes up to the total thickness retain local epitaxy to the substrate, with basal planes nonparallel to the substrate interface. Concurrently the (Ti1-x Alx) Ny layer is further reduced by inward Ti2 AlN grain growth along the basal planes. © 2007 American Institute of Physics.
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| 3. |
- Broering Chaar, Ana Beatriz, et al.
(författare)
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Microstructural influence of the thermal behavior of arc deposited TiAlN coatings with high aluminum content
- 2021
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 854
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Tidskriftsartikel (refereegranskat)abstract
- The influence of the microstructure on the thermal behavior of cathodic arc deposited TiAlN coatings was studied as a function of isothermal annealing. Two compositionally similar but structurally different coatings were compared, a Ti0·34Al0·66N0.96 coating with a fine-grain structure consisting of a mixture of cubic (c) and hexagonal (h) phases, and a Ti0·40Al0·60N0.94 coating with a coarse-grain structure of cubic phase. By in situ wide-angle synchrotron x-ray scattering, spinodal decomposition was confirmed in both coatings. The increased amount of internal interfaces lowered the decomposition temperature by 50 °C for the dual-phase coating. During the subsequent isothermal anneal at 1000 °C, a transformation from c-AlN to h-AlN took place in both coatings. After 50 min of isothermal annealing, atom probe tomography detected small amounts of Al (∼2 at.%) in the c-TiN rich domains and small amounts of Ti (∼1 at.%) in the h-AlN rich domains of the coarse-grained single-phase Ti0·40Al0·60N0.94 coating. Similarly, at the same conditions, the fine-grained dual-phase Ti0·34Al0·66N0.96 coating exhibits a higher Al content (∼5 at.%) in the c-TiN rich domains and higher Ti content (∼15 at.%) in the h-AlN rich domains. The study shows that the thermal stability of TiAlN is affected by the microstructure and that it can be used to tune the reaction pathway of decomposition favorably.
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| 4. |
- Cederfelt, S. I., et al.
(författare)
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Field validation of the droplet aerosol analyser
- 1997
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Ingår i: Atmospheric Environment. - 1352-2310. ; 31:16, s. 2657-2670
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Tidskriftsartikel (refereegranskat)abstract
- A new instrument for the study of cloud droplets and its relation to aerosol particles, the droplet aerosol analyser (DAA), was for the first time used in a field campaign. The DAA has the unique feature of measuring the ambient size of cloud droplets or cloud interstitial aerosol particles together with the size of its dry residue. This is obtained with a two-parameter data acquisition technique which results in a three-dimensional data set (ambient size, dry residue size, number concentration). The principle and design of the DAA is briefly described. The DAA was intercompared with differential mobility particle sizers, particulate volume monitors and a forward scattering spectrometer probe with respect to interstitial and cloud droplet dry residue size distribution as well as particle-size-dependent scavenging due to cloud droplet nucleation and for cloud droplet number concentration and size distribution and cloud liquid water concentration. Overall, the DAA showed good agreement with respect to all these six aerosol/cloud properties.
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| 5. |
- Chen, Yu-Hsiang, et al.
(författare)
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Effects of decomposition route and microstructure on h-AlN formation rate in TiCrAlN alloys
- 2017
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Ingår i: Journal of Alloys and Compounds. - : ELSEVIER SCIENCE SA. - 0925-8388 .- 1873-4669. ; 691, s. 1024-1032
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Tidskriftsartikel (refereegranskat)abstract
- The phase evolution of cubic (c), solid solution TixCr-0.37Al1-0.37-x N alloys with x = 0.03 and 0.16, and the kinetics of the hexagonal (h)-AlN formation are studied via in situ wide angle x-ray scattering experiments during high temperature (1000-1150 degrees C) annealing. Spinodal decomposition was observed in Ti0.16Cr0.36Al0.48N while Ti0.03Cr0.38Al0.59N decomposes through nucleation and growth of h-AlN, c-TiN and c-CrAlN. h-AlN is formed from c-CrAlN domains in both cases and the formation rate of h-AlN depends on the stability of the c-CrAlN domains. In Ti0.16Cr0.36Al0.48N, the c-CrAlN domains are stabilized by crystallographic coherency with the surrounding c-TiCrN in a microstructure originating from spinodal decomposition. This results in lower formation rates of h-AlN for this composition. These differences are reflected in higher activation energy for h-AlN formation in Ti0.16Cr0.36Al0.48N compared to Ti0.03Cr0.38Al0.59N. It also points out different stabilities of the intermediate phase c-CrAlN during phase decomposition of TiCrAlN alloys. Additional contributions to the low activation energy for formation of h-AlN in Ti0.03Cr0.38Al0.59N stems from precipitation at grain boundaries. (C) 2016 Elsevier B.V. All rights reserved.
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| 6. |
- Chen, Yu-Hsiang, et al.
(författare)
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Thermal and mechanical stability of wurtzite-ZrA1N/cubic-TiN and wurtzite-ZrA1N/cubic-ZrN multilayers
- 2017
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Ingår i: Surface & Coatings Technology. - : ELSEVIER SCIENCE SA. - 0257-8972 .- 1879-3347. ; 324, s. 328-337
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Tidskriftsartikel (refereegranskat)abstract
- The phase stability and mechanical properties of wurtzite (w)-Zr(0.25)A1(0.75)N/cubic (c)-TiN and w-Zr(0.25)A1(0.75)N/c-ZrN multilayers grown by arc evaporation are studied. Coherent interfaces with an orientation relation of c-TiN (111)[1-10]IIw-ZrAlN (0001)[11-20] form between ZrA1N and TiN sublayers during growth of the w-ZrAIN/c-TiN multilayer. During annealing at 1100 degrees C a c-Ti(Zr)N phase forms at interfaces between ZrA1N and TiN, which reduces the lattice mismatch so that the coherency and the compressive strain are partially retained, resulting in an increased hardness (32 GPa) after annealing. For the w-ZrAIN/c-ZrN multilayer, there is no coherency between sublayers leading to strain relaxation during annealing causing the hardness to drop. The retained coherency between layers and the compressive strain in the w-ZrAIN/c-TiN multilayer results in superior fracture toughness compared to the w-ZrAIN/c-ZrN multilayer as revealed by cross-sectional investigations of damage events under scratch and indentation tests. (C) 2017 Elsevier B.V. All rights reserved.
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| 7. |
- Gelali, E, et al.
(författare)
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iFISH is a publically available resource enabling versatile DNA FISH to study genome architecture
- 2019
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1, s. 1636-
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Tidskriftsartikel (refereegranskat)abstract
- DNA fluorescence in situ hybridization (DNA FISH) is a powerful method to study chromosomal organization in single cells. At present, there is a lack of free resources of DNA FISH probes and probe design tools which can be readily applied. Here, we describe iFISH, an open-source repository currently comprising 380 DNA FISH probes targeting multiple loci on the human autosomes and chromosome X, as well as a genome-wide database of optimally designed oligonucleotides and a freely accessible web interface (http://ifish4u.org) that can be used to design DNA FISH probes. We individually validate 153 probes and take advantage of our probe repository to quantify the extent of intermingling between multiple heterologous chromosome pairs, showing a much higher extent of intermingling in human embryonic stem cells compared to fibroblasts. In conclusion, iFISH is a versatile and expandable resource, which can greatly facilitate the use of DNA FISH in research and diagnostics.
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| 8. |
- Hastie, R., et al.
(författare)
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Associations Between Soluble fms-Like Tyrosine Kinase-1 and Placental Growth Factor and Disease Severity Among Women With Preterm Eclampsia and Preeclampsia
- 2022
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Ingår i: Journal of the American Heart Association (JAHA). - : Ovid Technologies (Wolters Kluwer Health). - 2047-9980. ; 11:16
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Tidskriftsartikel (refereegranskat)abstract
- Background The angiogenic factors soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) are postulated to be pathogenic disease drivers of preeclampsia. If true, then circulating levels should become more deranged with increasing disease severity. Methods and Results We investigated the association between circulating sFlt-1 and PlGF levels and severe adverse maternal outcomes among 348 women with preeclampsia. Compared with 125 women with preeclampsia without severe features, 25 women with preeclampsia and any of hemolysis, elevated liver enzymes, low platelet count syndrome, disseminated intravascular coagulation, or severe renal involvement had sFlt-1 levels that were 2.63-fold higher (95% CI, 1.81-3.82), sFlt-1/PlGF levels that were 10.07-fold higher (95% CI, 5.36-18.91) and PlGF levels that were 74% lower (adjusted fold change, 0.26 [95% CI, 0.18-0.39]). Compared with 125 women with preeclampsia without severe features, 37 with eclampsia had sFlt-1 levels that were 2-fold higher (2.02 [95% CI, 1.32-3.09]), sFlt-1/PIGF levels that were 4.71-fold higher (95% CI, 2.30-9.66) and PIGF levels that were 63% lower (0.43-fold change [95% CI, 0.27-0.68]). Compared with those without severe features, preeclampsia with severe hypertension (n=146) was also associated with altered angiogenic levels (sFlt-1, 1.71-fold change [95% CI, 1.39-2.11]; sFlt/PlGF, 2.91 [95% CI, 2.04-4.15]; PlGF, 0.59 [95%CI 0.47-0.74]). We also found that sFlt-1 and PlGF levels were altered by the number of maternal complications experienced. Conclusions Further angiogenic imbalance among women with preeclampsia is likely a pathogenic disease driver responsible for the life-threatening maternal complications.
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| 9. |
- Hodge, David B., et al.
(författare)
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Soluble and insoluble solids contributions to high-solids enzymatic hydrolysis of lignocellulose
- 2008
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 99:18, s. 8940-8948
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Tidskriftsartikel (refereegranskat)abstract
- The rates and extents of enzymatic cellulose hydrolysis of dilute acid pretreated corn stover (PCS) decline with increasing slurry concentration. However, mass transfer limitations are not apparent until insoluble solids concentrations approach 20% w/w, indicating that inhibition of enzyme hydrolysis at lower solids concentrations is primarily due to soluble components. Consequently, the inhibitory effects of pH-adjusted pretreatment liquor on the enzymatic hydrolysis of PCS were investigated. A response surface methodology (RSM) was applied to empirically model how hydrolysis performance varied as a function of enzyme loading (12-40 mg protein/g cellulose) and insoluble solids concentration (5-13%) in full-slurry hydrolyzates. Factorial design and analysis of variance (ANOVA) were also used to assess the contribution of the major classes of soluble components (acetic acid, phenolics, furans, sugars) to total inhibition. High sugar concentrations (130 g/L total initial background sugars) were shown to be the primary cause of performance inhibition, with acetic acid (15 g/L) only slightly inhibiting enzymatic hydrolysis and phenolic compounds (9 g/L total including vanillin, syringaldehyde, and 4-hydroxycinnamic acid) and furans (8 g/L total of furfural and hydroxymethylfurfural, HMF) with only a minor effect on reaction kinetics. It was also demonstrated that this enzyme inhibition in high-solids PCS slurries can be approximated using a synthetic hydrolyzate composed of pure sugars supplemented with a mixture of acetic acid, furans, and phenolic compounds, which indicates that generally all of the reaction rate-determining soluble compounds for this system can be approximated synthetically.
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| 10. |
- Kumar, B, et al.
(författare)
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Polycomb repressive complex 2 shields naïve human pluripotent cells from trophectoderm differentiation
- 2022
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Ingår i: Nature cell biology. - : Springer Science and Business Media LLC. - 1476-4679 .- 1465-7392. ; 24:6, s. 845-
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Tidskriftsartikel (refereegranskat)abstract
- The first lineage choice in human embryo development separates trophectoderm from the inner cell mass. Naïve human embryonic stem cells are derived from the inner cell mass and offer possibilities to explore how lineage integrity is maintained. Here, we discover that polycomb repressive complex 2 (PRC2) maintains naïve pluripotency and restricts differentiation to trophectoderm and mesoderm lineages. Through quantitative epigenome profiling, we found that a broad gain of histone H3 lysine 27 trimethylation (H3K27me3) is a distinct feature of naïve pluripotency. We define shared and naïve-specific bivalent promoters featuring PRC2-mediated H3K27me3 concomitant with H3K4me3. Naïve bivalency maintains key trophectoderm and mesoderm transcription factors in a transcriptionally poised state. Inhibition of PRC2 forces naïve human embryonic stem cells into an ‘activated’ state, characterized by co-expression of pluripotency and lineage-specific transcription factors, followed by differentiation into either trophectoderm or mesoderm lineages. In summary, PRC2-mediated repression provides a highly adaptive mechanism to restrict lineage potential during early human development.
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| 11. |
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| 12. |
- Manfred, Beckers, et al.
(författare)
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Microstructure and nonbasal-plane growth of epitaxial Ti2AlN thin films
- 2006
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Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 99:3, s. 034902-1-034902-8
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Tidskriftsartikel (refereegranskat)abstract
- Thin films of the Mn+1AXn (MAX) phase (M: early transition metal, A:A-group element, X: C and/or N, n=1-3) Ti2AlN were epitaxially grown onto single-crystal MgO(111) and MgO(100) substrates by dc reactive magnetron cosputtering from Ti and Al targets in an Ar/N2 gas mixture at a temperature of 690°C. To promote the nucleation of the MAX phase, a fcc (Ti0.63Al0.37)N seed layer was deposited before changing to Ti2AlN growth parameters. The nucleation processes have been studied by real-time in situ specular x-ray reflectivity. Independent of substrate orientation, the seed layer shows no roughening until its final thickness of approximately 100 Å, indicating pseudomorphic layer-by-layer growth. The MAX phase shows heteroepitaxial layer-by-layer growth on MgO(111), with increased surface roughening up to approximately 200 Å, whereas on MgO(100) the growth mode changes to Volmer-Weber-type already after three monolayers. X-ray scattering in Bragg-Brentano geometry of the final, approximately 1000 Å thick, Ti2AlN film reveals lattice parameters of c=13.463 Å and a=2.976 Å on the MgO(111) substrate and c=13.740 Å and a=2.224 Å on the MgO(100) substrate. From pole figure measurements the orientational relationship between film and substrate lattice was determined to be MgO{111}〈110〉//Ti2AlN{1012} 〈1210〉, regardless of the substrate orientation. This tilted, nonbasal-plane growth leads to a threefold grain orientation of Ti 2AlN along the MgO〈110〉 directions and a polycrystalline morphology confirmed by cross-sectional transmission electron microscopy. The growth can be assumed to take place in a lateral step-flow mode, i.e., emerging low surface free-energy (0001) planes, on which arriving atoms can diffuse until finding a step where they are bound to A facets. This growth process is irrespective of orientational relationship between substrate and film. However, in the present low-temperature case the partitioning of arriving Al and Ti atoms during nucleation is suppressed, which as a result of interfacial adaptation between substrate and film induces standing a-type planes during growth. © 2006 American Institute of Physics.
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| 13. |
- Manfred, Beckers, 2000-, et al.
(författare)
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Phase stability of epitaxially grown Ti2AlN thin films
- 2006
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 89:7
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Tidskriftsartikel (refereegranskat)abstract
- The phase stability of Mn+1AXn phase (M: early transition metal, A: A-group element, and X: C and/or N) Ti2AlN thin films reactively sputtered onto MgO(111) and Al2O3(0001) substrates has been investigated by in situ x-ray diffraction and Rutherford backscattering. High substrate temperature deposition results in epitaxial Ti2AlN growth with basal planes parallel to the substrate surface. In contrast to reported high thermal stability for bulk Ti-Al-N M n+1AXn phases in air, Ti2AlN thin films in vacuum decompose already at ∼800°C. The decomposition proceeds by outward Al diffusion and evaporation, followed by detwinning of the as-formed Ti2N atomic layers into cubic TiNx and intermediate phases. © 2006 American Institute of Physics.
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| 14. |
- Norrby, Niklas, et al.
(författare)
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In-situ x-ray scattering study of the cubic to hexagonal transformation of AlN in Ti1-xAlxN
- 2014
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Ingår i: Acta Materialia. - : Elsevier. - 1359-6454 .- 1873-2453. ; 73, s. 205-214
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Tidskriftsartikel (refereegranskat)abstract
- In the present work, we have studied the decomposition of arc evaporated Ti0.55Al0.45N and Ti0.36Al0.64N during heat treatment in vacuum by in-situ synchrotron wide angle x-ray scattering primarily to characterize the kinetics of the phase transformation of AlN from the cubic NaCl-structure to the hexagonal wurtzite-structure. In addition, in-situ small angle x-ray scattering measurements were conducted to explore details of the wavelength evolution of the spinodal decomposition, thus providing information about the critical size of the c-AlN rich domains prior to the onset of the h-AlN transformation. We report the fractional cubic to hexagonal transformation of AlN in Ti1-xAlxN as a function of time and extract activation energies between 320 and 350 kJ/mol dependent on alloy composition. The onset of the hexagonal transformation occurs at about 50 K lower temperature in Ti0.36Al0.64N compared to Ti0.55Al0.45N where the high Al content alloy also has a significantly higher transformation rate. A critical wavelength for the cubic domains of about 13 nm was observed for both alloys. Scanning transmission electron microscopy shows a c-TiN/h-AlN microstructure with a striking morphology resemblance to the c-TiN/c-AlN microstructure present prior to the hexagonal transformation.
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| 15. |
- Onyango, Onesmus O., et al.
(författare)
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Third delay in care of critically ill patients : a qualitative investigation of public hospitals in Kenya
- 2024
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Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Third delay refers to delays in delivering requisite care to patients after they arrive at a health facility. In low-resource care settings, effective triage and flow of care are difficult to guarantee. In this study, we aimed to identify delays in the delivery of care to critically ill patients and possible ways to address these delays.Design: This was an exploratory qualitative study using in-depth interviews and patient journeys. The qualitative data were transcribed and aggregated into themes in NVivo V.12 Plus using inductive and deductive approaches.Setting: This study was conducted in four secondary-level public Kenyan hospitals across four counties between March and December 2021. The selected hospitals were part of the Clinical Information Network.Participants: Purposive sampling method was used to identify administrative and front-line healthcare providers and patients. We conducted 12 in-depth interviews with 11 healthcare workers and patient journeys of 7 patients. Informed consent was sought from the participants and maintained throughout the study.Results: We identified a cycle of suboptimal systems for care with adaptive mechanisms that prevent quality care to critically ill patients. We identified suboptimal systems for identification of critical illness, inadequate resources for continuity care and disruption of the flow of care, as the major causes of delays in identification and the initiation of essential care to critically ill patients. Our study also illuminated the contribution of inflexible bureaucratic non-clinical business-related organisational processes to third delay.Conclusion: Eliminating or reducing delays after patients arrive at the hospital is a time-sensitive measure that could improve the care outcomes of critically ill patients. This is achievable through an essential emergency and critical care package within the hospitals. Our findings can help emphasise the need for standardised effective and reliable care priorities to maintain of care of critically ill patients.
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| 16. |
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| 17. |
- Rogström, Lina, et al.
(författare)
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A custom built lathe designed for in operando high-energy x-ray studies at industrially relevant cutting parameters
- 2019
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Ingår i: Review of Scientific Instruments. - : American Institute of Physics (AIP). - 0034-6748 .- 1089-7623. ; 90:10
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Tidskriftsartikel (refereegranskat)abstract
- We present a custom built lathe designed for in operando high-energy x-ray scattering studies of the tool-chip and tool-workpiece contact zones during operation. The lathe operates at industrially relevant cutting parameters, i.e., at cutting speeds amp;lt;= 400 m/min and feeds amp;lt;= 0.3 mm/rev. By turning tests in carbon steel, performed at the high-energy material science beamline P07 at Petra III, DESY, Hamburg, we observe compressive strains in TiNbAlN and Al2O3/Ti(C, N) coatings on the tool flank face during machining. It is demonstrated that by the right choice of substrate and coating materials, diffraction patterns can be recorded and evaluated in operando, both from the tool-workpiece and tool-chip contacts, i.e., from the contact zones between the tool and the workpiece material on the tool flank and rake faces, respectively. We also observe that a worn tool results in higher temperature in the tool-chip contact zone compared to a new tool. Published under license by AIP Publishing.
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| 18. |
- Rogström, Lina, et al.
(författare)
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Decomposition routes and strain evolution in arc deposited TiZrAlN coatings
- 2019
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Ingår i: Journal of Alloys and Compounds. - : ELSEVIER SCIENCE SA. - 0925-8388 .- 1873-4669. ; 779, s. 261-269
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Tidskriftsartikel (refereegranskat)abstract
- Phase, microstructure, and strain evolution during annealing of arc deposited TiZrAlN coatings are studied using in situ x-ray scattering and ex situ transmission electron microscopy. We find that the decomposition route changes from nucleation and growth of wurtzite AlN to spinodal decomposition when the Zr-content is decreased and the Al-content increases. Decomposition of Ti0.31Zr0.24Al0.45N results in homogeneously distributed wurtzite AlN grains in a cubic, dislocation-dense matrix of TiZrN consisting of domains of different chemical composition. The combination of high dislocation density, variation of chemical composition within the cubic grains, and evenly distributed wurtzite AlN grains results in high compressive strains, -1.1%, which are retained after 3 h at 1100 degrees C. In coatings with higher Zr-content, the strains relax during annealing above 900 degrees C due to grain growth and defect annihilation. (C) 2018 Elsevier B.V. All rights reserved.
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| 19. |
- Rogström, Lina, et al.
(författare)
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Thermal stability of wurtzite Zr1-xAlxN coatings studied by in situ high-energy x-ray diffraction during annealing
- 2015
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Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 118:3
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Tidskriftsartikel (refereegranskat)abstract
- We study the thermal stability of wurtzite (w) structure ZrAlN coatings by a combination of in situ high-energy x-ray scattering techniques during annealing and electron microscopy. Wurtzite structure Zr1-xAlxN coatings with Al-contents from x = 0.46 to x = 0.71 were grown by cathodic arc evaporation. The stability of the w-ZrAlN phase depends on chemical composition where the higher Al-content coatings are more stable. The wurtzite ZrAlN phase was found to phase separate through spinodal decomposition, resulting in nanoscale compositional modulations, i.e., alternating Al-rich ZrAlN layers and Zr-rich ZrAlN layers, forming within the hexagonal lattice. The period of the compositional modulations varies between 1.7 and 2.5 nm and depends on the chemical composition of the coating where smaller periods form in the more unstable, high Zr-content coatings. In addition, Zr leaves the w-ZrAlN lattice to form cubic ZrN precipitates in the column boundaries. (C) 2015 AIP Publishing LLC.
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| 20. |
- Schroeder, Jeremy, et al.
(författare)
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Industry-relevant magnetron sputtering and cathodic arc ultra-high vacuum deposition system for in situ x-ray diffraction studies of thin film growth using high energy synchrotron radiation
- 2015
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Ingår i: Review of Scientific Instruments. - : AMER INST PHYSICS. - 0034-6748 .- 1089-7623. ; 86:9, s. 095113-
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Tidskriftsartikel (refereegranskat)abstract
- We present an industry-relevant, large-scale, ultra-high vacuum (UHV) magnetron sputtering and cathodic arc deposition system purposefully designed for time-resolved in situ thin film deposition/annealing studies using high-energy (greater than50 keV), high photon flux (greater than10(12) ph/s) synchrotron radiation. The high photon flux, combined with a fast-acquisition-time (less than1 s) two-dimensional (2D) detector, permits time-resolved in situ structural analysis of thin film formation processes. The high-energy synchrotron-radiation based x-rays result in small scattering angles (less than11 degrees), allowing large areas of reciprocal space to be imaged with a 2D detector. The system has been designed for use on the 1-tonne, ultra-high load, high-resolution hexapod at the P07 High Energy Materials Science beamline at PETRA III at the Deutsches Elektronen-Synchrotron in Hamburg, Germany. The deposition system includes standard features of a typical UHV deposition system plus a range of special features suited for synchrotron radiation studies and industry-relevant processes. We openly encourage the materials research community to contact us for collaborative opportunities using this unique and versatile scientific instrument. (C) 2015 AIP Publishing LLC.
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