The effect of testing procedure on DSC measurements of Gd-Ti-Zr alloy using ZrO2 container

Differential Scanning Calorimetry (DSC) was applied to determine the critical temperatures of phase transformations in the Gd40Ti30Zr30 alloy (wt%). The comparative measurements were carried out using three types of measuring devices at a temperature RT- 1650°C in the same flowing gas (Ar, 99.9992%) but applying different testing procedures, which allowed obtaining dissimilar oxygen contents in the surrounding atmosphere. The high temperature interaction and reactivity taking place between molten alloy samples and ZrO2 container during DSC tests were evaluated by structural analysis of the resulting interfaces using alloy samples solidified inside the ZrO2 containers. The conducted research has demonstrated methodological difficulties accompanying measurements of the thermophysical properties of Gd-rich alloys by the container-assisted DSC method, particularly when the tests are performed in flowing argon atmosphere with significantly reduced oxygen content. Under non-oxidizing conditions, the degradation of ZrO2 container can take place during DSC testing because the selected Gd40Ti30Zr30 alloy reacts with the ZrO2 to form a continuous interfacial reaction product layer. Under slightly oxidizing conditions, the gadolinium oxide formed in situ on the alloy surface, plays the role of a barrier for direct contact between molten alloy and container and thus may suppress or even prevent the degradation of the container and its subsequent strong bonding with the holder

Wetting behaviour and reactivity between liquid Gd and ZrO2 substrate

The wetting behavior and reactivity between molten pure Gd and polycrystalline 3YSZ substrate (ZrO2 stabilized with 3 wt% of Y2O3)were experimentally determined by a sessile drop method using a classical contact heating coupled with drop pushing procedure. The test was performed under an inert flowing gas atmosphere (Ar) at two temperatures of 1362°C and 1412°C. Immediately after melting (Tm=1341°C), liquid Gd did not wet the substrate forming a contact angle of θ=141°. The non-wetting to wetting transition (θ < 90°) took place after about 110 seconds of interaction and was accompanied by a sudden decrease in the contact angle value to 67°. Further heating of the couple to 1412 °C did not affect wetting (θ=67°±1°). The solidified Gd/3YSZ couple was studied by means of optical microscopy and scanning electron microscopy coupled with X-ray energy dispersive spectroscopy. Structural investigations revealed that the wettability in the Gd/3YSZ system is of a reactive nature associated with the formation of a continuous layer of a wettable reaction product Gd2Zr2O7

Advance care planning in cystic fibrosis: Current practices, challenges, and opportunities

AbstractBackgroundStudies in cystic fibrosis (CF) report late attention to advance care planning (ACP). The purpose of this study was to examine ACP with patients receiving care at US adult CF care programs.MethodsChart abstraction was used to examine ACP with adults with CF dying from respiratory failure between 2011 and 2013.ResultsWe reviewed 210 deaths among 67 CF care programs. Median age at death was 29years (range 18–73). Median FEV1 in the year preceding death was 33% predicted (range 13–100%); 68% had severe lung disease with FEV1p=pp=0.55). The frequency of ACP varied significantly among the 29 programs contributing data from four or more deaths.ConclusionsACP in CF often occurs late in the disease course. Important decisions default to surrogates when opportunities for ACP are missed. Provision of ACP varies significantly among adult CF care programs. Careful evaluation of opportunities to enhance ACP and implementation of recommended approaches may lead to better practices in this important aspect of CF care

Wettability and reactivity of ZrB2 substrates with liquid Al

Wetting characteristics of the Al/ZrB2 system were experimentally determined by the sessile drop method with application of separate heating of the ZrB2 and Al samples and combined with in situ cleaning of Al drop from native oxide film directly in vacuum chamber. The tests were performed in ultrahigh vacuum of 10−6 mbar at temperatures 710, 800, and 900 °C as well as in flowing inert gas (Ar) atmosphere at 1400 °C. The results evidenced that liquid Al does not wet ZrB2 substrate at 710 and 800 °C, forming high contact angles (θ) of 128° and 120°, respectively. At 900 °C, wetting phenomenon (θ < 90°) occurs in 29th minute and the contact angle decreases monotonically to the final value of 80°. At 1400 °C, wetting takes place immediately after drop deposition with a fast decrease in the contact angle to 76°. The solidified Al/ZrB2 couples were studied by scanning and transmission electron microscopy coupled with x-ray energy diffraction spectroscopy. Structural characterization revealed that only in the Al/ZrB2 couple produced at the highest temperature of 1400 °C new phases (Al3Zr, AlB2 and α-Al2O3) were formed

Motor neuron diseases caused by a novel VRK1 variant – A genotype/phenotype study

Background: Motor neuron disorders involving upper and lower neurons are a genetically and clinically heterogenous group of rare neuromuscular disorders with overlap among spinal muscular atrophies (SMAs) and amyotrophic lateral sclerosis (ALS). Classical SMA caused by recessive mutations in SMN1 is one of the most common genetic causes of mortality in infants. It is characterized by degeneration of anterior horn cells in the spinal cord, leading to progressive muscle weakness and atrophy. Non-SMN1-related spinal muscular atrophies are caused by variants in a number of genes, including VRK1, encoding the vaccinia- related kinase 1 (VRK1). VRK1 variants have been segregated with motor neuron diseases including SMA phenotypes or hereditary complex motor and sensory axonal neuropathy (HMSN), with or without pontocerebellar hypoplasia or microcephaly. Results: Here, we report an association of a novel homozygous splice variant in VRK1 (c.1159 + 1G>A) with childhood-onset SMA or juvenile lower motor disease with brisk tendon reflexes without pontocerebellar hypoplasia and normal intellectual ability in a family with five affected individuals. We show that the VRK1 splice variant in patients causes decreased splicing efficiency and a mRNA frameshift that escapes the nonsensemediated decay machinery and results in a premature termination codon. Conclusions: Our findings unveil the impact of the variant on the VRK1 transcript and further support the implication of VRK1 in the pathogenesis of lower motor neuron diseases

Оценка напряженно-деформированного состояния элементов конструкции шасси с учетом междуэлементных связей

Стаття присвячена дослідженню впливу міжелементних зв’язків в конструкції на її напружено–деформований стан. Методом скінченних елементів проведено аналіз напружено–деформованого стану деталі з урахуванням між елементних зв’язків та без врахування їх впливу. Отримані результати дозволяють якісно оцінити вплив змін на конструкцію.This article is devoted to studying the influence of interelement ties in the construction of its stress-strain state. The method of finite element analyzes of stress-strain state element design of the chassis in two settlement cases. The first simulation model does not account for the relationship of elements and perceives stress direction. In the second calculation model accounted for between elemental connections. Comparing results shows that the distribution of stresses in lugs latches in the calculation methodology for the development of very different character from the stress distribution that we obtain using classical methods by emergence date due to not linear apposition effort. Maximum loads are placed in the area of the spout and valves are 370 MPa in both study models, but the distribution and importance of stress significantly are different. The values of stresses in the transition zone of I-structures in lugs the calculation model taking into account of interelement connections reaches 49 MPa, and the calculation without relationship – 88 MPa. It should also be noted that in the first case, the elements in the zone of transition work on stretching and the second compression. Value tensions in the area eyelet lugs the calculation model taking into account of interelement ties to 21.6 MPa, and the calculation without considering the relationship reaches to 33.9 MPa. It should also be noted that the nature of the deformation eyelet significantly different. The results can serve as input data for rapid assessment of the stress-strain state design of the chassis in the design of new products and changes to existing designs.Статья посвящена исследованию влияния межэлементных связей в конструкции на ее напряженно-деформированное состояние. Методом конечных элементов проведен анализ напряженно-деформированного состояния детали с учетом межэлементных связей и без учета их влияния. Полученные результаты позволяют качественно оценить влияние изменений на конструкцию