Investigation of Quasi-Static and Dynamic Material Properties of a Structural Sheet Molding Compound Combined with Acoustic Emission Damage Analysis

Sheet molding compounds (SMC) are discontinuously fiber-reinforced thermosets, attractive to the automotive industry due to their outstanding specific strength and stiffness, combined with a cost efficient manufacturing process. Increasingly important for structural components, a structural SMC-based improved resin formulation featuring no fillers is investigated in this study. The influence of fiber volume content, fiber length, and manufacturing induced fiber orientation on quasi-static and dynamic mechanical properties of vinylester-based SMC is characterized. Stiffness and strength increased with increasing fiber volume content for tensile, compression, and flexural loadings. Fiber length distribution did not significantly influence the mechanical properties of the material. The movement of the conveyor belt leads to an anisotropic fiber orientation and orientation-dependent mechanical properties. Acoustic emission coupled with machine learning algorithms enabled the investigation of the damage mechanisms of this discontinuous glass fiber SMC. The acoustic emission analysis was validated with micro computed tomography of damaged specimens. The dominant failure mechanisms of the SMC exposed to bending loading were matrix cracking and interface failure

Oxidation and Release of Ruthenium from White Inclusions

In this paper the laboratory test results on oxidation and release of ruthenium as a fission product element are summarised. The ruthenium appears in the nuclear fuel pellets of pressurized water reactors as one of the fission product elements during burnup. In case of severe accident when the air can contact the degraded hot fuel, the ruthenium oxidises and its gaseous oxides, especially the RuO4, release rapidly from the pellets to the environment. Because of high radio- and chemotoxicity of ruthenium tetra-oxide further experimental study of oxidation and release is essential. It is well known that ruthenium in the irradiated fuel UO2 fuel appears in small metallic alloy precipitations together with fission product elements as Mo, Rh, Pd and Tc. The precipitations are seen in the metallographic pictures as white inclusions. This separate effect study focused on the differences in the release rate of gaseous ruthenium oxides when pure ruthenium or Mo-Ru-Rh-Pd metallic alloy is present in the simulated nuclear fuel. The oxidation and release were studied at constant reaction temperatures of 1000 or 1100 Celsius. The tests showed that during high-temperature oxidation of the Mo-Ru-Rh-Pd alloy in air flow the release rate of gaseous ruthenium oxides is reduced to 60-80% compared to the value measured in case of oxidation of pure metallic ruthenium powder in the same thermal-hydraulic conditions. Furthermore, if additional elements and chemical compounds representing other fission products were added in the alloy, a time delay of 30 to 60 min appeared in the release of gaseous ruthenium to the room-temperature environment. One of the main results was that in the outlet air flow reaching the environment the partial pressure of RuO4 was far above what could be expected for room-temperature equilibrium conditions. It was pointed out that the highly volatile RuO4 can decompose in solid, non-volatile RuO2 and O2. The X-ray fluorescence analysis results showed that some ruthenium compounds deposited on the colder circuit walls of the test facility. This suggests RuO4 is not fully airstable, i.e., its stability in air can be limited in time.JRC.F.4-Nuclear design safet

The effect of food environments on fruit and vegetable intake as modified by time spent at home: a cross-sectional study.

OBJECTIVE: There is a growing body of research that investigates how the residential neighbourhood context relates to individual diet. However, previous studies ignore participants' time spent in the residential environment and this may be a problem because time-use studies show that adults' time-use pattern can significantly vary. To better understand the role of exposure duration, we designed a study to examine 'time spent at home' as a moderator to the residential food environment-diet association. DESIGN: Cross-sectional observational study. SETTINGS: City of Toronto, Ontario, Canada. PARTICIPANTS: 2411 adults aged 25-65. PRIMARY OUTCOME MEASURE: Frequency of vegetable and fruit intake (VFI) per day. RESULTS: To examine how time spent at home may moderate the relationship between residential food environment and VFI, the full sample was split into three equal subgroups--short, medium and long duration spent at home. We detected significant associations between density of food stores in the residential food environment and VFI for subgroups that spend medium and long durations at home (ie, spending a mean of 8.0 and 12.3 h at home, respectively--not including sleep time), but no associations exist for people who spend the lowest amount of time at home (mean=4.7 h). Also, no associations were detected in analyses using the full sample. CONCLUSIONS: Our study is the first to demonstrate that time spent at home may be an important variable to identify hidden population patterns regarding VFI. Time spent at home can impact the association between the residential food environment and individual VFI

Oxidation and Release of Ruthenium from Short Fuel Rods above 1500oC

The fission product ruthenium is radiotoxic and in oxidized form as ruthenium-tetroxide (RuO4) also chemical toxic. During fuel element change or in case of a leakage in fuel storages, air flows in the containment or fuel storage. If the circulation pump fails, the fuel elements are heated-up, and at high temperatures gaseous ruthenium oxides are formed and rapidly released from the fuel. Due to the significant higher volatility of RuO4 in the Chernobyl Catastrophe the measured concentration of the Ru-isotopes in the fall-outs was comparable to those of iodine and caesium. In order to get more insight in the chemical and physical behaviour of this fission product under severe accident conditions, the Ruthenium release was studied in a series of Separate Effect Tests (RUSET). In the test short fuel rod segments were used and exposed to air and steam atmosphere at high temperatures. The experiments in air atmosphere showed, that the partial pressures of the released Ru-oxides was two orders of magnitudes lower compared to those measured in previous tests with Ru-powder diluted in a ZrO2 matrix. It was found that ruthenium was not released in steam atmosphere in the examined temperature range. Furthermore, the temperature dependence of the deposition was detected by XRF analysis.JRC.F.4-Nuclear design safet

Mucinaea (Hyacinthaceae-Urgineoideae), a Remarkable New Genus from Namaqualand (Northern Cape Province, South Africa)

We here describe a new genus from Namaqualand, which is based on Tenicroa nana Snijman. Mucinaea M. Pinter, Mart.-Azorín, U. Müll.-Doblies, D. Müll.- Doblies, Pfosser & Wetschnig gen. nov. shows several character-states different from all other known species of Tenicroa and a few even do not occur in any other genus of Hyacinthaceae. Mucinaea M. Pinter & al. is easily distinguishable by its purplish-pink tepals bearing a double-eyed green floral marking at their base, surrounded by a white margin, unique within Hyacinthaceae. It also differs by the single sheathing cataphyll without raised transverse ribs, different from the other species of Tenicroa, and by the second sheath consisting of a compound of the bases of about ten foliage leaves, surrounding about ten further free foliage leaves, what is a unique structure in the bulbous world. Mucinaea with Mucinaea nana (Snijman) M. Pinter & al. comb. nova is a monotypic genus, only known from three quarter - degree squares in the Northern Cape Province of South Africa. Data on morphology, ecology and distribution are given. Additionally, this separation leads to the monophyly of the genus Tenicroa

Predictors of Lesion Cavitation After Recent Small Subcortical Stroke

The Wellcome Trust (WT088134/Z/09/A) and Row Fogo Charitable Trust funded the Mild Stroke Study 2 from which the patients were selected. We thank the European Union Horizon 2020, PHC-03-15, project no. 666881, ‘SVDs@Target’, the Fondation Leducq Transatlantic Network of Excellence for the Study of Perivascular Spaces in Small Vessel Disease, ref. no. 16 CVD 05, and the MRC UK Dementia Research Institute for support.Peer reviewedPublisher PD

Experimental investigation of the late phase of spent fuel pool accidents

Experimental programmes have been carried out in order to investigate the behaviour of nuclear fuel components in high-temperature air atmosphere, which characterises the main conditions of the late phase of spent fuel pool accidents. The tests provided new data on the oxidation of zirconium cladding in different atmospheres, on the oxidation and release of ruthenium from fuel pellets and on the integral behaviour of fuel bundles. The integral test confirmed that water injection into the spent fuel storage pool is the right measure to terminate a severe accident

Psychological factors and brain magnetic resonance imaging metrics associated with fatigue in persons with multiple sclerosis.

BACKGROUND Besides demographics and clinical factors, psychological variables and brain-tissue changes have been associated with fatigue in persons with multiple sclerosis (pwMS). Identifying predictors of fatigue could help to improve therapeutic approaches for pwMS. Therefore, we investigated predictors of fatigue using a multifactorial approach. METHODS 136 pwMS and 49 normal controls (NC) underwent clinical, neuropsychological, and magnetic resonance imaging examinations. We assessed fatigue using the "Fatigue Scale for Motor and Cognitive Functions", yielding a total, motor, and cognitive fatigue score. We further analyzed global and subcortical brain volumes, white matter lesions and microstructural changes (examining fractional anisotropy; FA) along the cortico striatal thalamo cortical (CSTC) loop. Potential demographic, clinical, psychological, and magnetic resonance imaging predictors of total, motor, and cognitive fatigue were explored using multifactorial linear regression models. RESULTS 53% of pwMS and 20% of NC demonstrated fatigue. Besides demographics and clinical data, total fatigue in pwMS was predicted by higher levels of depression and reduced microstructural tissue integrity in the CSTC loop (adjusted R2 = 0.52, p < 0.001). More specifically, motor fatigue was predicted by lower education, female sex, higher physical disability, higher levels of depression, and self-efficacy (adjusted R2 = 0.54, p < 0.001). Cognitive fatigue was also predicted by higher levels of depression and lower self-efficacy, but in addition by FA reductions in the CSTC loop (adjusted R2 = 0.45, p < 0.001). CONCLUSIONS Our results indicate that depression and self-efficacy strongly predict fatigue in MS. Incremental variance in total and cognitive fatigue was explained by microstructural changes along the CSTC loop, beyond demographics, clinical, and psychological variables