Thermal cycle stability of Co 64 V 15 Si 17 Al 4 high-temperature shape memory alloy

Abstract(#br)The microstructure, martensitic transformation and thermal cycle stability of Co 64 V 15 Si 17 Al 4 high-temperature shape memory alloy were studied. The results show that the martensite transformation of L2 1 /D0 22 occurred in the Co 64 V 15 Si 17 Al 4 alloy. In the Co 64 V 15 Si 17 Al 4 alloy, the transformation temperatures of forward transformation and reverse transformation are pretty high, reaching 589.6 °C and 649.1 °C, respectively. The temperatures of the martensitic transformation and the transformation heat show a neglectable difference after 200 thermal cycles in the alloy. This alloy exhibits good thermal stability during 200 thermal cycles between room temperature and 850 °C, in which the microstructure and martensitic transformation behavior have no obvious change

Humic acid production from the degradation of Yima coal by Cunninghamella elegans combined with Bacillus sp.

Biodegradation is one of the important ways for the clean and efficient utilization of coal. However, the effectiveness of degradation by the combination of fungi and bacteria has not been well understood. In the present study, the combined degradation of the Yima coal was tested. The coal samples were firstly oxidized with nitric acid, followed by cultured in the media of Cunninghamella elegans and Bacillus sp.. The absorbance of A450, pH and metallic element (Cr, As, Mn, Pb, Co, Ni, Cu, Zn, Mo) contents of the degradation solution were determined by UV-visible spectrophotometry, pH meter and inductively coupled plasma mass spectrometry, respectively. The humic acid was analyzed by element analyzer, Fourier transform infrared spectroscopy and gas chromatog-raphy-mass spectrometry. The results showed that the humic acid yields of C. elegans, Bacillus sp. and their mixture were 58.17%, 61.00% and 67.17%, respectively. The pH of the degradation solution of mixed strains was similar to that of the bacteria. The characteristic products of the bacteria degradation were detected in the humic acid samples derived from mixed strains, while the opposite was true for the fungi. It was suggested that the combination of the two strains enhanced the alkaline environment and improved the degradation rate of nitric acid-treated coal. The bacteria played a leading role in the degradation process. Metallic elements (Cr, As, Mn, Pb, Co, Ni, Cu, Zn, Mo) were transferred from coal to the degradation solution during the degradation process, and the contents of Cr, As, Pb, Ni, Cu and Mo were fitted with A450, the coefficient of determination (R2) were greater than 0.6. It indicated that the contents of these six metal elements in the degradation solution could represent the degradation rate. Chemically extracted humic acid and biologically extracted humic acid were rich in the active functional groups such as carboxyl, hydroxyl, carbonyl, long-chain fatty acids (C16, C18) and four pyrrole derivatives. The biologically extracted humic acid also contained fatty acids (C3, C4, C5, C13, C14, C15), of smaller molecular weight, as well as nitrogen-containing compounds such as two pyrrole derivatives and a furan. The contents of C and H elements in the biologically extracted humic acid were higher than that in the chemically extracted humic acid

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed

A numerical study on artificial fill embankment with liquefiable foundation using FLAC

The problem of seismic liquefaction related to artificial fill embankment is complicated. In this study, by making using of Finn model, a typical artificial fill embankment was simulated by means of Finn model in FLAC. Numerical simulation results indicated that the pore water pressure of saturated sand soil increased extremely which resulted in the significant decrease of the effective stress. When the effective stress decreased approximately to zero, the liquefaction phenomena occurred. According to the change of pore water pressure at different locations and depths, three rules have been obtained. Firstly, the occurrence time for the first peak of pore water pressure coincided with the seismic peak acceleration of input wave. Secondly, the liquefaction occurred earlier in the upper layer of saturated sand soil than in the lower layer below the bottom of slope. However the duration of liquefaction in the lower layer of saturated sand soil was longer than in the upper layer. Thirdly, the upper layer of saturated sand soil was almost not liquefiable below the top of slope, while the lower layer was easily liquefiable with long duration time. In summary, the characteristics of seismic liquefaction in the artificial fill embankment were closely related to the seismic wave, locations and depths of saturated sand soil in a slope. 2013 American Society of Civil Engineers