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[en] We probe the convergence of the configuration interaction (CI) approach for harmonically trapped one-dimensional Fermi–Fermi mixtures. Existing scientific papers that apply the CI approach to study such systems typically use harmonic oscillator eigenfunctions with fixed frequency parameter values as bases. We show that CI’s optimisation is the key to reducing the computational cost of the numerical study of fermionic mixtures. The effectiveness of the optimised CI approach is analysed in terms of its ability to capture the spatial fermion–fermion correlations. (author)
[en] This news is based on the following article: Nyhan M.M., Coull B.A., Blomberg A.J., et al. Associations between ambient particle radioactivity and blood pressure: the NAS (Normative Aging Study), Journal of the American Heart Association 2018; 7(6), pii: e008245, doi:10.1161/JAHA.117.008245. The authors of this study show an association between higher exposure to radioactivity measured in particulate matter and increased blood pressure (diastolic and systolic). This relation is found for exposures averaged over the day of measurement and the previous days (moving averages) for up to 28 days. The meaning of this association needs to be clarified. (author)
[en] An attempt has been made to study the consequences of stagnation point flow of nanomaterial toward nonlinear variable sheet. Nanoparticles comprise Brownian movement and thermophoresis effects. Thermal radiation and convective boundary conditions are considered. Applied magnetic flux of strength (𝐵0) is implemented in vertical direction. The nonlinear system is tackled through homotopy method. Energy equation is modeled in the presence of thermal radiation, convective conditions and heat generation/absorption. The impact of several flow variables on the momentum, energy and concentration is graphically discussed. Concluding remarks are presented. (author)
[en] Over-stabilized foam has always been a problem that plagues the dodecylamine (DDA) flotation system. In this study, a new device, “automatic foam analyzer”, was successfully used to characterize the behavior of foam in DDA solution. The effects of pH and DDA dosage on the foam properties were investigated from four aspects: bubble diffusion capacity, Bikerman coefficient, half-life period and solution conductivity, and the mechanism of pH and DDA concentration on foam properties was analyzed by solution chemistry and surface tension of DDA, then the change process of foam structure was deduced. The results showed that the foaming property and stability of DDA bubbles were the best at pH=8. Simultaneously, with the increase of DDA dosage, the foaming property of bubbles was enhanced, the half-life was prolonged, and the foam stability was also improved. (author)
[en] The distributions of trace amounts of natural radionuclides in soil samples were studied. The K40, Na22, Sr91 radioisotopes were identified in all soil samples taken from Shirvan region of the Azerbaijan. The analyses carried out by gamma spectroscopy showed that in all soil samples the concentrations of natural radioisotopes Na22, K40, and Sr91 are 2.7, 2.5, and 0.57 Bq/kg, respectively. The cleaning methods of soil contaminated with radionuclides have been studied. By systematic studies have determined that with all cleaning methods, the degree of K40 extraction from soil samples is about 3-7 times lower than the release of Na22, and Sr91. The method of cleaning the soil from radionuclides by extraction with weak acidic and alkaline solutions is more effective than other cleaning methods.
[en] The present paper numerically investigated the dual solutions of Carreau nanofluids in the presence of Cattaneo–Christov double diffusion with focus on heat and mass transfer which contains the effects of Brownian motion and thermophoresis parameter. A nonlinearly shrinking sheet has been utilized to create the flow. The thermal and concentration diffusions are considered by introducing Cattaneo–Christov fluxes. This paper provides information about the energy and concentration equations which are constructed with the help of Cattaneo–Christov double-diffusion theory in the existence of Brownian motion parameter and thermophoresis parameter. The study showed the local similarity variables are used to renovate the governing equations into a set of nonlinear ordinary differential equations. The ascending differential system which is a collection of momentum, temperature and concentration equations is preserved through a numerical approach called the Runge–Kutta–Fehlberg integration technique. The study reveals that the multiple solutions occur for the different vital physical parameters, for example, suction parameter s, Weissenberg number We, Prandtl number Pr, velocity slip parameter δ, viscosity ratio parameter β∗, non-dimensional thermal relaxation time δe, Brownian motion parameter Nb and thermophoresis parameter Nt. Moreover, higher values of thermal relaxation time δe decrease the temperature profile. (author)
[en] Vesicular systems such as niosomes provide an alternative to improve drug delivery vehicles. Niosomes and liposomes are similar in terms of their structure and physical properties having applications in food, pharmaceutical and cosmetic industries. The efficiency of a drug delivery vehicle is strongly dependent on its components which decide its interaction with partitioned drug(s) and locus of site of partitioning. In order to obtain quantitative insights into partitioning and release of drugs (mitoxantrone and ketoprofen) in niosomes, ultrasensitive calorimetry, spectroscopy and microscopy have been employed to establish structure-function energetics relationships which could provide guidance towards rational drug design and choice of suitable nonionic surfactant based drug delivery vehicles. The study was focused on drug partitioning in already prepared niosomes, and drug release from niosomes with partitioned drugs in the layers of vesicles
[en] The present article investigates the flow and heat transfer of Sisko nanofluid over a permeable vertical stretching surface in a porous medium. The effect of buoyancy, suction, and viscous dissipation has been taken into account. Buongiorno’s model of nanofluid consisting of thermophoresis and Brownian diffusion has been considered. Moreover, zero nanoparticle mass flux condition is employed at the boundary which leads to a more realistic physical problem. Using a suitable transformation governing partial differential equations of fluid flow are transformed into a set of nonlinear ordinary differential equations (ODEs). The numerical solution of nonlinear ODEs are obtained using the finite difference technique in MATLAB. The influence of physical parameters viz. buoyancy parameter (λ*), porosity parameter (β*), thermophoresis parameter (Nt*), suction parameter (f*W), Sisko material parameter (A*), Brinkman number (Br*), Brownian diffusion parameter (Nb*) and Lewis number (Le*) on velocity, temperature and nanoparticle volume fraction are shown graphically. Moreover, to understand the physical phenomenon in the boundary layer region, the numerical values of skin friction and Nusselt number are calculated and presented through table values. It has been found that the Brownian diffusion has a negligible impact on Nusselt number relative to the results obtained in previous studies, where nanoparticle volume fraction on the boundary was actively controlled. The obtained results disclose that the buoyancy parameter increases the velocity of fluid while it reduces the temperature. Suction parameter reduces both velocity and temperature, whereas the porosity parameter reduces velocity and enhances the temperature and nanoparticle volume fraction. (author)
[en] Self-compacting concrete (SCC) contains fine mineral fillers such as limestone powder. The idea of this study was to partially replace limestone with waste sulfur since it is hydrophobic, insoluble in water and therefore chemically inert and to compare the properties of produced concrete samples. Fresh concrete properties included: slump-flow, t500, V-funnel time, L-box ratio, segregation ratio, density, and entrained air content. Hardened concrete was tested for compressive, flexural and bond strengths, ultrasonic velocity, dynamic elasticity modulus, dynamic Poisson’s ratio, and microstructure. Flowability and segregation increased, while bulk density, compressive and flexural strength, dynamic elasticity modulus and ultrasonic velocity slight declined. Times t500 and V-funnel time, L-box ratio and entrained air changed insignificantly. Considering that all properties should remain or improve in case of waste valorization and the criteria should set to satisfy requirements for SCC, this study proved that all mixtures can be used for structural applications.
[es]El hormigón autocompactante (SCC, del inglés Self-compacting concrete) contiene cargas (fillers) minerales finas como polvo de piedra caliza. La idea de este estudio fue reemplazar parcialmente la piedra caliza por contenido de residuos de azufre, ya que es hidrófobo, insoluble en agua y, por lo tanto, químicamente inerte, y comparar las propiedades de las muestras de hormigón producidas. Las propiedades analizadas en el hormigón fresco incluyeron: flujo de asentamiento, t500, tiempo del embudo en V (V-funnel time), relación de caja en L (L-box ratio), relación de segregación, densidad y contenido de aire ocluido. En el hormigón endurecido se analizó la resistencia a compresión, flexión y adherencia, velocidad ultrasónica, módulo dinámico de elasticidad, coeficiente dinámico de Poisson y microestructura. La fluidez y la segregación aumentaron, mientras que la densidad aparente (bulk density), la resistencia a la compresión y la flexión, el módulo de elasticidad dinámica y la velocidad ultrasónica disminuyeron ligeramente. Los tiempos t500 y el tiempo del embudo V, la relación de la caja L y el aire ocluido cambiaron de manera insignificante. Considerando que al valorizar residuos, se deben conseguir propiedades similares o mejoradas, y que los criterios deben establecerse para satisfacer los requisitos de SCC, este estudio demostró que todas las mezclas se pueden utilizar para aplicaciones estructurales.
[en] We have explored multiple solutions for non-Newtonian Casson nanofluid flow past a moving extending sheet under the influence of variable thermal conductivity and nonlinear radiation through a permeable medium with convective boundary conditions. The governing equations are transformed to ODEs by similarity transformations and then solved numerically by the Chebyshev pseudospectral (CPS) method. Dual solutions are obtained for velocity, temperature and nanoparticle concentration distributions with different values of physical parameters. In the present analysis, it was found that, the nonlinearity formula for thermal radiation gives a realistic description of nanofluid mathematical model depending on the existence of nanoscale particles. Furthermore, the concentration of nanoparticles is highly influenced by nonlinear thermal radiation due to the sizes of nanofluid, where linear radiation has a weak effect on the concentration distributions of nanoparticles. These results are very important in medicine, and more specifically for reinforcing the delivery of drugs through the skin, as the nanoparticle entrapment of drugs enhances delivery to, or absorption by, target cells. The transdermal drug delivery system offers huge clinical advantages over other dosage forms. As transdermal drug delivery offers controlled as well as predetermined rate of release of the drug into the patient, it can keep up steady-state nanofluid concentration. (author)