351 research outputs found

    NON-LINEAR REGRESSION ANALYSIS IN UPFLOW ANAEROBIC SLUDGE BLANKET REACTOR

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    A dimensionless approach was used to model the granule size variation in upflow anaerobic sludge blanket (UASB) reactor under different operating condition like organic loading rate, operating time, gas production rate, volatile suspended solids, suspended solids, upflow velocity, polymer loading, sludge volume index and effluent COD concentrations. Present study examines mathematically the effect of introducing polymers to enhance the granule size development in a UASB reactor especially in treatment of low strength wastewater in UASB reactor. The experimental results of investigators on different operating conditions were collected and subjected to dimensionless and non-linear regression analysis to model the enhancement of granule size in UASB reactor. The results using the dimensionless approach and the non linear regression show that better prediction of granule size variations for the data set based on the statistical estimates, errors and a satisfactory coefficient of determination (R2-values). The dimensionless approach of the present study can be successfully used to predict the granule size variations in UASB reactor

    3-(4-Bromo­phen­yl)quinazolin-4(3H)-one

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    In the title compound, C14H9BrN2O, the quinazoline unit is essentially planar, with a mean deviation of 0.058 (2) Å from the least-squares plane defined by the ten constituent ring atoms. The dihedral angle between the mean plane of the quinazoline ring system and the 4-bromo­phenyl ring is 47.6 (1)°. In the crystal, mol­ecules are linked by inter­molecular C—H⋯N and C—H⋯O hydrogen bonds, forming infinite chains of alternating R 2 2(6) dimers and R 2 2(14) ring motifs

    3-(4-Chloro­phen­yl)quinazolin-4(3H)-one

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    In the title compound, C14H9ClN2O, the quinazoline unit is essentially planar, with a mean deviation from the least-squares plane defined by the ten constituent ring atoms of 0.027 (2) Å. The dihedral angle between the mean plane of the quinazoline ring system and the 4-chloro­phenyl ring is 44.63 (5)°. In the crystal, mol­ecules are linked by inter­molecular C—H⋯N and C—H⋯O hydrogen bonds, forming infinite chains of alternating R22(6) dimers and R22(14) ring motifs

    Josephson diode effect from Cooper pair momentum in a topological semimetal

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    Cooper pairs in non-centrosymmetric superconductors can acquire finite centre-of-mass momentum in the presence of an external magnetic field. Recent theory predicts that such finite-momentum pairing can lead to an asymmetric critical current, where a dissipationless supercurrent can flow along one direction but not in the opposite one. Here we report the discovery of a giant Josephson diode effect in Josephson junctions formed from a type-II Dirac semimetal, NiTe2. A distinguishing feature is that the asymmetry in the critical current depends sensitively on the magnitude and direction of an applied magnetic field and achieves its maximum value when the magnetic field is perpendicular to the current and is of the order of just 10 mT. Moreover, the asymmetry changes sign several times with an increasing field. These characteristic features are accounted for by a model based on finite-momentum Cooper pairing that largely originates from the Zeeman shift of spin-helical topological surface states. The finite pairing momentum is further established, and its value determined, from the evolution of the interference pattern under an in-plane magnetic field. The observed giant magnitude of the asymmetry in critical current and the clear exposition of its underlying mechanism paves the way to build novel superconducting computing devices using the Josephson diode effect

    Premenopausal cardiovascular disease and age at natural menopause: a pooled analysis of over 170,000 women

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    Early menopause is associated with an increased risk of subsequent cardiovascular disease (CVD). Few studies have investigated the converse. We examined whether premenopausal CVD events are associated with early age at menopause. We pooled the individual data of 177,131 women from nine studies. We used multinomial logistic regression models to estimate multivariable relative risk ratios (RRR) and 95% confidence intervals (CI) for the associations between age at onset of premenopausal CVD events-including coronary heart disease (CHD) and stroke-and age at natural menopause. Altogether 1561 (0.9%) premenopausal participants reported CVD events (including 1130 CHD and 469 stroke) at a mean age of 41.3 years. Compared with women without any premenopausal CVD events, women who experienced a first CVD event before age 35 years had a twofold risk of menopause before age 45 years (early menopause); adjusted RRR (95% CI) of 1.92 (1.17, 3.14) for any CVD, 1.86 (1.01, 3.43) for CHD and 2.17 (1.43, 3.30) for stroke. Women who experienced a first premenopausal CVD event after age 40 years underwent a natural menopause at the expected age (around 51 years). These associations were robust to adjustment for smoking status, BMI, educational level, race/ethnicity, age at menarche, parity, hypertension and family history of CVD. For premenopausal women, a first CVD event before age 35 years is associated with a doubling of the risk of an early menopause, while a first CVD event occurred after 35 years indicates a normal menopause at around 51 years. Shared genetic and environmental factors (such as smoking), as well as compromised vasculature following CVD events, may contribute to this outcome
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