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Supersonic impulse turbines are commonly used to harvest waste heat from systems based on organic Rankine cycles, automotive applications, and gas-generator liquid rocket engines. This research aims to design and analyze a single-stage supersonic turbine with a rated power of approximately 440 KW. We present a comprehensive preliminary design roadmap followed by design parameters optimization. The preliminary sizing is carried out using one-dimensional flow analysis, while the blade geometrical design is performed using the two-dimensional method of characteristics. The turbine performance is then analyzed through numerical simulations on three-dimensional models. Comprehensive parametric analyses are conducted to examine the turbine performance sensitivity to changes in partial admission (PA), mean radius, and turbine blade height using three-dimensional sliding mesh techniques (SMT). The current analysis simulates the full turbine to capture PA effects, rather than focusing on a single periodic sector as is common in turbomachinery simulation practices. Different PA scenarios are investigated, emphasizing a single rotor passage over a complete rotor cycle in a partially admitted turbine, and examining its charging and discharging mechanisms. Flow tracking over such a blade shows that the turbine rotor exhibits compressor-like behavior over most of the unadmitted zone, contributing to efficiency drops and severe transients. • Preliminary design roadmap for partially admitted supersonic impulse turbine. • Parametric study using high-fidelity three-dimensional unsteady CFD analysis employing sliding mesh technique. • Obtaining an optimized design with reduced size and improved efficiency. • Investigating single-rotor transient flow dynamics at different partial admission ratios. • Analysis of partial admission arc distribution effect on turbine performance, mechanical loading, and operational lifespan. [ABSTRACT FROM AUTHOR]

The nanocomposites (NCs) based on hydroxyapatite (HAP) could be improved into biologically safe and effective antibacterial materials. Combining HAP with copper oxide (CuO) and graphene oxide (GO) in a ternary nanocomposite (TNC) increased the human osteoblast viability in vitro to about 98.3% ± 3%. The structure was also analyzed with XRD, FTIR, XPS. The average roughness (Ra) decreased from 68.2 to 42.4 nm, while the root mean square roughness (Rq) changed slightly from 55.5 to 54.4 nm. The TEM investigation showed a decrease in the diameter and length of nanorod particles from 14 to 37 nm to 11 and 34 nm. In addition, the nano strip particles decreased from 17 to 14 nm in diameter, while a change in length was from 151 to 139 nm in diameter and length, respectively. The nanorods belong to HAP, while nanostrips belong to CuO. The polarization resistance decreased from 108 to around 44.5 (ohm.cm2). The antibacterial activity was done against the gram-negative E. coli, and the gram-positive S. aureus where inhibition zones reached 17.1 ± 1.3 and 14.3 ± 0.7 mm, respectively. The enhancement in cell viability and antibacterial behavior indicate the biocompatibility of the biomaterials for biomedical applications. [ABSTRACT FROM AUTHOR]

Laser ablation technique was utilized to synthesize versatile metallic nanoparticles including ZnO, Ag and CuO which were incorporated into the blend matrix of cellulose Acetate (CA) and ε-polycaprolactone (PCL) nanofibrous scaffold. The compositional, microstructural and morphological behaviors for the obtained nanofibers were investigated using X-ray diffraction (XRD), Fourier Transformed Infrared, Transmission Electron Microscope (TEM) and Field Emission-Scanning Electron Microscope (FESEM). The cell viability and antibacterial activity were investigated against Staphylococcus aureus (S. aureus) and Escherichia coli (E -coli). TEM micrographs refer that while CuONPs were involved in the middle of CA/PCL fibrous scaffold with diameters around 160 nm. The morphological investigations indicated the scaffolds were configured in a non-oriented form with diameters 0.45–0.9 μm in the case of ZnONPs involved in blend matrix fibers. The ratio of viable cells displays that compositions are biocompatible, while the antibacterial activity of both AgNPs and CuONPs showed an inhibition zone around 11.2.3 ± 2.2 mm and 9.4 ± 1.2 mm respectively. Bio-blend polymers matrices carrying nanoparticles could be tailored for a plethora of biomedical applications upon their compositions. [ABSTRACT FROM AUTHOR]

The fabrication of nanostructure local delivery system from a biocompatible biomaterial is highly requested for biomedical applications. The therapeutic use of thallium was halted for its toxicity. We hypothesize that doping it on a biocompatible composite can work as a drug delivery system for its potential antineoplastic activity. In this study, a novel co-substitution containing Tl/Se ions within carbonated hydroxyapatite (CHAP) has been synthesized using a facial precipitation method at different concentrations of Tl ions. The as-synthesized samples were investigated using XRD, which revealed a growth in a-axis rather than c-direction upon the elevation of Tl content. The topological investigations performed by SEM assured this growth trend and showed that the grain size was in the range of 1.4–3.5 μm at x = 0.6. The surface charge measured by zeta potential illustrated that the highest negativity was −15.95 mV and it was achieved at x = 0.6. The anticancer activity was assessed at the in vitro level by MTT assay against human non-small cell lung cancer cell line (A549) and human fibroblast-like fetal lung cell line (WI 38). The determined IC 50 values after 24 and 72 h of incubation showed a significantly more potent effect on the cancerous cell line compared to the normal one; 10 and 2 times, respectively at x = 0.6. Cell cycle and death mode analysis of treated cancerous cells by flow cytometry indicated a cell cycle arrest at G2/M phase and a prominent apoptotic activity. That was confirmed by the up-regulation of the pro-apoptotic genes; cytochrome c , caspase 3 and TP53 as measured by qRT-PCR. These findings suggest that the newly synthesized composite may play a pivotal role in cancer treatment and are encouraging for future in vivo investigations. Image 1 [ABSTRACT FROM AUTHOR]

Abstract: The effect of initial and couple stresses on the propagation and attenuation of seismic body waves in a dissipative orthotropic medium is considered. In the limiting cases, the phase velocities of P-wave and SV-wave along coordinate axes are deduced. The study shows that the presence of compressive initial stresses increases the velocity of longitudinal wave (P-wave) but diminishes that of transverse wave (SV-wave). It also observed that the loss of longitudinal wave due to dissipation is maximum in the initially stress-free case and decreases as the initial stress increases. In the case of transverse wave, the presence of initial stresses decreases the loss factor up to the point of when the direction of propagation makes an angle of 40° with direction of initial stress, and then increases. It can be concluded that both the velocities and attenuations depend on not only the material constants but also on the initial stresses present in the medium and the direction of wave propagation. Also, it has been shown that the couple stress has no effect on both velocities and attenuations of seismic waves propagating in this medium. [Copyright &y& Elsevier]

Abstract: The eigenvalue approach, using the Laplace and Fourier transforms, has been employed to find the analytical expressions for displacements and stresses at any point, as a result of an inclined line load, of an initially stressed orthotropic elastic medium. A plain strain problem has been studied. The results in the form of displacement and stress components have been obtained and discussed graphically for a particular model. In this paper it is shown that the displacement and stress components are affected by initial stresses in the medium. [Copyright &y& Elsevier]

Abstract: The present work deals with the encounter problem of two small masses m 2 and m 3 describing initially elliptical orbits around a massive oblate primary. The equations of motion are developed, up to the power of the small parameter, both for the center of mass and for the relative motion of m 2 and m 3 without any restrictions on the orbital elements. The equations of motion of the center of mass are expressed in terms of the Struble variables. [Copyright &y& Elsevier]

The critical inclination problem in artificial satellite theory and the post-Newtonian (PN) effects on it are discussed. The Hamiltonian is constructed and is expressed in terms of the Delaunay variables containing the zonal harmonics up to J4 and the PN contributions up to order J2/cl2. The Hamiltonian is ordered out such that the PN terms are of order J2. Two successive canonical transformations based on Lie series and transform are carried out to remove short- and long-period terms from the Hamiltonian, respectively. Terms are retained up to third order in the secular and to the second order in the periodic terms, where J2 is considered of first order. [Copyright &y& Elsevier]

The critical inclination problem in artificial satellite theory and the post-Newtonian (PN) effects on it are discussed. The Hamiltonian is constructed and is expressed in terms of the Delaunay variables containing the zonal harmonics up to J4 and the PN contribution up to order J2/cl2. The Hamiltonian is ordered out such that the PN terms are of order J2. Two successive canonical transformations based on Lie series and transform are carried out to remove short and long period terms from the Hamiltonian, respectively. Terms are retained up to the third order in the secular perturbations and to the second order in the periodic perturbations, where J2 is considered of first order. [Copyright &y& Elsevier]