5,939 research outputs found

    Combined Effect of Multistage Processing and Treatment Methods on the Physical, Chemical, and Microstructure Properties of Recycled Concrete Aggregates

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    This research aims to examine the effects of multi-stage processing on reducing the old cement fractions and enhancing the quality of CRA (concrete recycled aggregate). The investigation involves the use of demolished concrete debris and subsequent treatments in both single and multi-stage processes. The recycled aggregates (RA) were obtained using a multi-stage jaw crushing process followed by utilising natural aggregate, untreated RA, RA treated with hydrochloric acid and sodium silicate immersion (single stage treatment) and RA treated with mechanical scrubbing and sodium silicate immersion in two separate stages (multi-stage treatment). The subsequent phase of the experimental inquiry involves assessing the physical attributes of both treated and untreated RA. This is followed by conducting microstructural examinations utilising techniques such as scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetry-differential thermal analysis (TG-DTA). The findings indicate that employing a two-step process, involving mechanical abrasion followed by immersion in sodium silicate, yields high-quality CRA. This conclusion is reinforced by the favourable physical performance observed. The water absorption values of CRA were lowered by 78% through single-stage treatments such as immersion in hydrochloric acid. The similar treatment is found to show densest concrete with Ca/Si ratio reduced to around 81% to that of untreated CRA. Additionally, for single stage treated CRA samples, microstructural study using FTIR verified the creation of additional hydration products, whereas for two stages treated CRA specimens, TGA analysis demonstrated the formation of stable CSH. According to the findings, it is advised to use a multi-stage process of jaw crushing, then treating it with mechanical abrasion and sodium silicate. This has the ability to improve the physical, chemical, and microstructural properties of CRA

    An effective bound on Generalized Diophantine m-tuples

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    For non-zero integers nn and k2k\geq2, a generalized Diophantine mm-tuple with property Dk(n)D_k(n) is a set of mm positive integers S={a1,a2,,am}S = \{a_1,a_2,\ldots, a_m\} such that aiaj+na_ia_j + n is a kk-th power for 1i<jm1\leq i< j\leq m. Define Mk(n):=sup{S:SM_k(n):= \sup\{|S| : S has property Dk(n)}D_k(n)\}. In a recent work, the second author, S. Kim and M. R. Murty proved that Mk(n)M_k(n) is O(logn)O(\log n), for a fixed kk, as we vary nn. In this paper, we obtain effective upper bounds on Mk(n)M_k(n). In particular, we show that for k2k\geq 2, Mk(n)3ϕ(k)lognM_k(n) \leq 3\,\phi(k)\, \log n, if nn is sufficiently larger than kk

    Race affects SVR12 in a large and ethnically diverse hepatitis C-infected patient population following treatment with direct-acting antivirals: Analysis of a single-center Department of Veterans Affairs cohort.

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    Hepatitis C virus (HCV) infection is a major cause of chronic liver disease. HCV cure has been linked to improved patient outcomes. In the era of direct-acting antivirals (DAAs), HCV cure has become the goal, as defined by sustained virological response 12&nbsp;weeks (SVR12) after completion of therapy. Historically, African-Americans have had lower SVR12 rates compared to White people in the interferon era, which had been attributed to the high prevalence of non-CC interleukin 28B (IL28B) type. Less is known about the association between race/ethnicity and SVR12 in DAA-treated era. The aim of the study is to evaluate the predictors of SVR12 in a diverse, single-center Veterans Affairs population. We conducted a retrospective study of patients undergoing HCV therapy with DAAs from 2014 to 2016 at the VA Greater Los Angeles Healthcare System. We performed a multivariable logistic regression analysis to determine predictors of SVR12, adjusting for age, HCV genotype, DAA regimen and duration, human immunodeficiency virus (HIV) status, fibrosis, nonalcoholic fatty liver disease (NAFLD) fibrosis score, homelessness, mental health, and adherence. Our cohort included 1068 patients, out of which 401 (37.5%) were White people and 400 (37.5%) were African-American. Genotype 1 was the most common genotype (83.9%, N&nbsp;=&nbsp;896). In the adjusted models, race/ethnicity and the&nbsp;presence of fibrosis were statistically significant predictors of non-SVR. African-Americans had 57% lower odds for reaching SVR12 (adj.OR&nbsp;=&nbsp;0.43, 95% CI&nbsp;=&nbsp;1.5-4.1) compared to White people. Advanced fibrosis (adj.OR&nbsp;=&nbsp;0.40, 95% CI&nbsp;=&nbsp;0.26-0.68) was also a significant predictor of non-SVR. In a single-center VA population on DAAs, African-Americans were less likely than White people to reach SVR12 when adjusting for covariates

    Linear independence of values of the qq-exponential and related functions

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    In this paper, we derive results concerning the linear independence of values of the qq-exponential and certain cognate functions at algebraic arguments when the associated modulus qq is a Pisot-Vijayraghavan number. As a consequence, we deduce the irrationality of special values of these functions, some of which were known earlier using alternate methods

    Development and Evaluation of Cefadroxil Drug Loaded Biopolymeric Films Based on Chitosan-Furfural Schiff Base

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    Cefadroxil drug loaded biopolymeric films of chitosan-furfural schiff base were prepared by reacting chitosan with furfural in presence of acetic acid and perchloric acid respectively for the external use. Prepared films were evaluated for their strength, swelling index, thickness, drug content, uniformity, tensile strength, percent elongation, FTIR spectral analysis and SEM. The results of in vitro diffusion studies revealed that the films exhibited enhanced drug diffusion as compared to the films prepared using untreated chitosan. The films also demonstrated good to moderate antibacterial activities against selective gram positive and gram negative bacteria

    Relativistic calculations of the lifetimes and hyperfine structure constants in 67^{67}Zn+^{+}

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    This work presents accurate {\it ab initio} determination of the magnetic dipole (M1) and electric quadrupole (E2) hyperfine structure constants for the ground and a few low-lying excited states in 67^{67}Zn+^{+}, which is one of the interesting systems in fundamental physics. The coupled-cluster (CC) theory within the relativistic framework has been used here in this calculations. Long standing demands for a relativistic and highly correlated calculations like CC can be able to resolve the disagreements among the lifetime estimations reported previously for a few low-lying states of Zn+^{+}. The role of different electron correlation effects in the determination of these quantities are discussed and their contributions are presented.Comment: 9 pages, 1 figure. submitted to J. Phys. B Fast Trac

    Coordination properties of vic-isonitrosoimines in their copper (II) and palladium (II) complexes

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    Preparation and structural characterization of palladium (II) complexes of ligands III-V and copper (II) complexes of III are reported. The elemental analyses of the complexes show that the metal: ligand ratio is 1:2. The electrical conductance in acetone shows the non-electrolytic nature of the complexes. The diamagnetic character suggests a gross square-planar geometry for the palladium (II) complexes. Copper (II) complexes are paramagnetic with &#956;eff.~1·90 B.M. Spectral data suggest that in all the complexes the ligand coordinates to the metal (II) symmetrically through isonitroso-nitrogen and imine-nitrogen, forming a five membered chelate ring. Amine-exchange reactions of the complexes are discussed and compared on the basis of their structures

    Optimal Multi-Modes Switching Problem in Infinite Horizon

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    This paper studies the problem of the deterministic version of the Verification Theorem for the optimal m-states switching in infinite horizon under Markovian framework with arbitrary switching cost functions. The problem is formulated as an extended impulse control problem and solved by means of probabilistic tools such as the Snell envelop of processes and reflected backward stochastic differential equations. A viscosity solutions approach is employed to carry out a finne analysis on the associated system of m variational inequalities with inter-connected obstacles. We show that the vector of value functions of the optimal problem is the unique viscosity solution to the system. This problem is in relation with the valuation of firms in a financial market

    DNA-Binding Interaction Studies of Microwave Assisted Synthesized Sulfonamide Substituted 8-Hydroxyquinoline Derivatives

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    Sulfonamide substituted 8-hydroxyquinoline derivatives were prepared using a microwave synthesizer. The interaction of sulfonamide substituted 8-hydroxyquinoline derivatives and their transition metal complexes with Plasmid (pUC 19) DNA and Calf Thymus DNA were investigated by UV spectroscopic studies and gel electrophoresis measurements. The interaction between ligand/metal complexes and DNA was carried out by increasing the concentration of DNA from 0 to 12 μl in UV spectroscopic study, while the concentration of DNA in gel electrophoresis remained constant at 10 μl. These studies supported the fact that, the complex binds to DNA by intercalation via ligand into the base pairs of DNA. The relative binding efficacy of the complexes to DNA was much higher than the binding efficacy of ligands, especially the complex of Cu-AHQMBSH had the highest binding ability to DNA. The mobility of the bands decreased as the concentration of the complex was increased, indicating that there was increase in the interaction between the metal ion and DNA. Complexes of AHQMBSH were excellent for DNA binding as compared to HQMABS
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