Ab-initio elastic tensor of cubic Ti0.5_{0.5}Al0.5_{0.5}N alloy: the dependence of the elastic constants on the size and shape of the supercell model

In this study we discuss the performance of approximate SQS supercell models in describing the cubic elastic properties of B1 (rocksalt) Ti$_{0.5}$Al$_{0.5}$N alloy by using a symmetry based projection technique. We show on the example of Ti$_{0.5}$Al$_{0.5}$N alloy, that this projection technique can be used to align the differently shaped and sized SQS structures for a comparison in modeling elasticity. Moreover, we focus to accurately determine the cubic elastic constants and Zener's type elastic anisotropy of Ti$_{0.5}$Al$_{0.5}$N. Our best supercell model, that captures accurately both the randomness and cubic elastic symmetry, results in $C_{11}=447$ GPa, $C_{12}=158$ GPa and $C_{44}=203$ GPa with 3% of error and $A=1.40$ for Zener's elastic anisotropy with 6% of error. In addition, we establish the general importance of selecting proper approximate SQS supercells with symmetry arguments to reliably model elasticity of alloys. In general, we suggest the calculation of nine elastic tensor elements - $C_{11}$, $C_{22}$, $C_{33}$, $C_{12}$, $C_{13}$, $C_{23}$, $C_{44}$, $C_{55}$ and $C_{66}$, to evaluate and analyze the performance of SQS supercells in predicting elasticity of cubic alloys via projecting out the closest cubic approximate of the elastic tensor. The here described methodology is general enough to be applied in discussing elasticity of substitutional alloys with any symmetry and at arbitrary composition.Comment: Submitted to Physical Review

An end to Nordic exceptionalism? Europeanisation and Nordic development policies

The Nordic countries have traditionally been praised for their generous and advanced development policies. Recently, however, it has been claimed that the Nordic model has faded: that the Nordic donors have become more similar to other European donors. One possible reason for such trends is influences from EU policies, that is, Europeanisation. This article critically evaluates such claims by presenting arguments for and against Europeanisation effects. We argue that changes have indeed taken place. The Nordic exceptionalism has been eroded. At the same time, a convergence of European aid policies has occurred. The question is if this is the consequence of Europeanisation – or is it rather a result of Nordicisation (the Nordic countries influencing the EU), or perhaps like-mindisation (a broader set of progressive member states having impact upon EU policies)? We suggest that Europeanisation has been extremely weak while there is strong evidence of Nordicisation but also, and increasingly, of like-mindisation. Today, a core group of mainly northern member states, including the Nordics, are the main driving forces behind European aid convergence

Шляхи удосконалення підготовки учнів до олімпіад з фізики

(uk) Стаття присвячена проблемі формування основ методики складання задач та завдань для олімпіад з фізики учнів середніх навчальних закладів освіти.(ru) Статья посвящена проблеме формирования основ методики составления задач и заданий для олимпиад по физике учащихся средних учебных заведений образования

CV4 Impact of Short Periods with Improved or Worsened INR Control on Life Expectancy and QALYs in Patients with Atrial Fibrillation

ObjectivesWarfarin-treated patients with poor international normalized ratio (INR) control, measured with time in therapeutic range (TTR) or the standard deviation of transformed INR (SDTINR), have an increased risk for clinical events. To what extent only a short period with an altered INR control may influence outcomes remains unknown. This study assessed the impact of transient periods of improved or worsened INR control on life expectancy and quality-adjusted life years (QALYs) among warfarin-treated patients with atrial fibrillation (AF) using both metrics.MethodsWarfarin-treated patients with AF, registered in the patient record system Journalia during years 1985-2000, were included. Information on all-cause mortality was collected from the Cause of Death Register. Scenarios where patients were assumed to have a transiently altered INR control during 30 days were modeled statistically using hazard functions, and the impact on remaining life expectancy and QALYs was assessed.ResultsWhen using SDTINR, a 70-year old man within the 2.5th worst INR control percentile was estimated to gain 10.8 days of life or 0.0168 QALYs from a 30-day improvement in INR control to that of an average 70-year old man. Correspondingly, 15.5 days of life or 0.0196 QALYs would be lost if a 70-year old man within the 2.5th best INR control percentile would have an average INR control during 30 days. The magnitudes were smaller when TTR was used to determine INR control.ConclusionsEven short periods of altered INR control is expected to have impact on life expectancy and QALYs among patients with AF

Теоретичний аналіз динаміки розвитку творчої активності дошкільника

(uk) У статті проаналізовано динаміку розвитку творчої активності дошкільника. Зазначається, що процес формування особистості дошкільника досягається під час самореалізації її в творчій діяльності. Особлива увага приділена характеристиці етапів розвитку свідомості та творчій взаємодії «дитина – дорослий». Обґрунтовується необхідність створення сприятливих умов щодо творчої активності дошкільника.(ru) В статье проанализирована динамика развития творческой активности дошкольника. Отмечается, что процесс формирования личности дошкольника достигается во время самореализации ее в творческой деятельности. Особое внимание уделено характеристике этапов развития сознания и творческому взаимодействию «ребенок – взрослый». Обосновывается необходимость создания благоприятных условий относительно творческой активности дошкольника

Enhanced thermal stability and fracture toughness of TiAlN coatings by Cr, Nb and V-alloying

The effect of metal alloying on mechanical properties including hardness and fracture toughness were investigated in three alloys, Ti~0.33Al0.50(Me)~0.17N (Me¿=¿Cr, Nb and V), and compared to Ti0.50Al0.50N, in the as-deposited state and after annealing. All studied alloys display similar as-deposited hardness while the hardness evolution during annealing is found to be connected to phase transformations, related to the alloy's thermal stability. The most pronounced hardening was observed in Ti0.50Al0.50N, while all the coatings with additional metal elements sustain their hardness better and they are harder than Ti0.50Al0.50N after annealing at 1100¿°C. Fracture toughness properties were extracted from scratch tests. In all tested conditions, as-deposited and annealed at 900 and 1100¿°C, Ti0.33Al0.50Nb0.17N show the least surface and sub-surface damage when scratched despite the differences in decomposition behavior and h-AlN formation. Theoretically estimated ductility of phases existing in the coatings correlates well with their crack resistance. In summary, Ti0.33Al0.50Nb0.17N is the toughest alloy in both as-deposited and post-annealed states.Peer ReviewedPostprint (author's final draft

Fall risk assessment predicts fall-related injury, hip fracture, and head injury in older adults

Objectives To investigate the role of a fall risk assessment, using the Downton Fall Risk Index (DFRI), in predicting fall‐related injury, fall‐related head injury and hip fracture, and death, in a large cohort of older women and men residing in Sweden. Design Cross sectional observational study. Setting Sweden. Participants Older adults (mean age 82.4 ± 7.8) who had a fall risk assessment using the DFRI at baseline (N = 128,596). Measurements Information on all fall‐related injuries, all fall‐related head injuries and hip fractures, and all‐cause mortality was collected from the Swedish Patient Register and Cause of Death Register. The predictive role of DFRI was calculated using Poisson regression models with age, sex, height, weight, and comorbidities as covariates, taking time to outcome or end of study into account. Results During a median follow‐up of 253 days (interquartile range 90–402 days) (>80,000 patient‐years), 15,299 participants had a fall‐related injury, 2,864 a head injury, and 2,557 a hip fracture, and 23,307 died. High fall risk (DFRI ≥3) independently predicted fall‐related injury (hazard ratio (HR) = 1.43, 95% confidence interval (CI) = 1.39–1.49), hip fracture (HR = 1.51, 95% CI =1.38–1.66), head injury (HR = 1.12, 95% CI = 1.03–1.22), and all‐cause mortality (HR = 1.39, 95% CI = 1.35–1.43). DFRI more strongly predicted head injury (HR = 1.29, 95% CI = 1.21–1.36 vs HR = 1.08, 95% CI = 1.04–1.11) and hip fracture (HR = 1.41, 95% CI = 1.30–1.53 vs HR = 1.08, 95% CI = 1.05–1.11) in 70‐year old men than in 90‐year old women (P < .001). Conclusion Fall risk assessment using DFRI independently predicts fall‐related injury, fall‐related head injury and hip fracture, and all‐cause mortality in older men and women, indicating its clinical usefulness to identify individuals who would benefit from interventions

Self-organized nanostructuring in Zr0.69Al0.31N thin films studied by atom probe tomography

We have applied atom probe tomography (APT) to analyze self-organizing structures of wear-resistant Zr0.69Al0.31N thin films grown by magnetron sputtering. Transmission electron microscopy shows that these films grow as a three-dimensional nanocomposite, consisting of interleaved lamellae in a labyrinthine structure, with an in-plane size scale of ~ 5 nm. The structure was recovered in the Al APT signal, while the Zr and N data lacked structural information. The onset of the self-organized labyrinthine growth was observed to occur by surface nucleation, 5–8 nm above the MgO substrate, due to increasing Zr–Al compositional fluctuations during elemental segregation. At a final stage, the labyrinthine growth mode was observed to be interrupted by the formation of larger ZrN grains

Grinding-induced metallurgical alterations in the binder phase of WC-Co cemented carbides

The metallic binder phase dictates the toughening behavior of WC-Co cemented carbides (hardmetals), even though it occupies a relative small fraction of the composite. Studies on deformation and phase transformation of the binder constituent are scarce. Grinding represents a key manufacturing step in machining of hardmetal tools, and is well-recognized to induce surface integrity alterations. In this work, metallurgical alterations of the binder phase in ground WC-Co cemented carbides have been assessed by a combination of electron back scattered diffraction and transmission electron microscopy techniques. The Co-base binder experiences a martensitic phase transformation from fcc to hcp crystal structure, predominantly in the first 5 µm below the surface. The hcp fraction decreases gradually along a depth of 10 µm. Surface Co displays severe plastic deformation under the highest strain, resulting in formation of nanocrystalline grains in the first micrometer below the surface. Microstructural refinement within the binder phase is observed even at greater depth. Stacking faults were detected in most of the refined grains. The metallurgical alterations of the binder phase modify the local stress distribution during grinding, which affects the discerned subsurface microcracking. The resulting residual stress profile is the sum of multiple subsurface changes, such as phase transformation, severe plastic deformation and grain refinement, where it is discerned that the depth profile of the transformed hcp-Co fraction coincides with the grinding-induced residual stress profile.Peer ReviewedPostprint (author's final draft