Modeling and analysis of peristalsis of hybrid nanofluid with entropy generation

Journal of Thermal Analysis and Calorimetry - This investigation intends to explore the peristaltic transport of rotating fluid in a channel. The channel is considered symmetric with flexible...     

Solvent-free synthesis and antibacterial studies of some quinolinones

Abstract  

Solvent-free, microwave-induced condensation of 2-aminoaryl alkyl ketones and ethyl 3-oxobutanoate in the presence of amberlite Na sr1L gave quinolinones in high yield when compared to other catalysts. Further, N-alkylation of the quinolinones was carried out effectively with various halides using amberlite Na sr1L. An N-alkylated quinolinone exhibited enhanced activities against B. subtilis, E. coli, and P. aeruginosa, similar to standard drug ampicillin. Two compounds showed effective activity against S. aureus, and one resulted in moderate activity against E. coli.     

Effects of the Stepped-Doped Lower Waveguide and a Doped p-Cladding Layer on AlGaN-Based Deep-Ultraviolet Laser Diodes

Journal of Russian Laser Research - The performance of deep ultraviolet (DUV) laser diodes (LDs) may be affected by structural variations in the composition of AlGaN devices. In this work, we...     

Congestion‐Aware Handover in LTE Systems for Load Balancing in Transport Network

Long‐Term Evolution employs a hard handover procedure. To reduce the interruption of data flow, downlink data is forwarded from the serving eNodeB (eNB) to the target eNB during handover. In cellular networks, unbalanced loads may lead to congestion in both the radio network and the backhaul network, resulting in bad end‐to‐end performance as well as causing unfairness among the users sharing the bottleneck link. This work focuses on congestion in the transport network. Handovers toward less loaded cells can help redistribute the load of the bottleneck link; such a mechanism is known as load balancing. The results show that the introduction of such a handover mechanism into the simulation environment positively influences the system performance. This is because terminals spend more time in the cell; hence, a better reception is offered. The utilization of load balancing can be used to further improve the performance of cellular systems that are experiencing congestion on a bottleneck link due to an uneven load.     

Composite of natural bamboo (Dendrocalamus strictus) and TiO2: Its photocatalytic potential in the degradation of methylene blue under the direct irradiation of solar light

Composites of visible-light-active bamboo charcoal powder (BCP)/TiO₂ were fabricated by the straight calcination method by using TiCl₄ as the source of titanium and natural bamboo as the carbon source. The dispersion of TiO₂ nanoparticles was observed onto the surface of the BCP. The introduction of microstructure sizes of the bamboo powder played an important role in enhancing the optical properties of BCP/TiO₂ composites. The composites of BCP/TiO₂ showed the photocatalytic activities both under visible-light irradiation and UV irradiation. The methylene blue dye was used as the experimental check-up. The photodegradation reactions followed zero-order and pseudo-first-order kinetics. In the time duration of 100 min, about 58.31% and 95% of methylene blue were degraded by TiO₂ and BCP/TiO_2, respectively; 60 min more time was required by TiO₂ to achieve 93% of degradation. This suggests that addition of BCP helps in the reduction in time and also shows high durability after up to four cycles having the degradation efficiencies of 95%, 94.1%, 92.7% and 86.6%, respectively. Hence, this research could overlay in the domain of green energy.

     

A note on acoustic diffraction by an absorbing finite strip in a moving fluid

The problem of cylindrical acoustic wave diffraction from an absorbing finite barrier in a moving fluid has been investigated in an improved form. The diffracted field in the far zone has already been discussed in [1], but due to some mathematical complications, the absorbing parameter was ignored in that study. In the present analysis, the absorbing parameter is taken into account up to order one and presented in a better form solution. Moreover, the solution obtained in this analysis can be used to recover the results for the case of semi-infinite barrier [2] by taking an appropriate limit l → ∞. The results for still fluid can also be gathered by taking the value of Mach number to be zero. The integral transforms, Wiener-Hopf techniques and asymptotic expansions are used to acquire the diffracted field in the far zone. Finally, the solution is well supported by the graphical results showing the effects of various physical parameters on the separated field.     

Synthesis,characterization and antimicrobial studies of mixed ligand silver(I) complexes of thioureas and triphenylphosphine; crystal structure of {[Ag(PPh3)(thiourea)(NO3)]2·[Ag(PPh3)(thiourea)]2(NO3)2}

Mixed ligand silver(I) complexes of triphenylphosphine and thioureas (thiourea (Tu), N-methylthiourea (Metu), N,N′-dimethylthiourea (Dmtu) and N,N′-diethylthiourea (Detu)) with the general formulae, [(Ph₃P)₂Ag(thione)]NO₃ and [(Ph₃P)Ag(thione)₂]NO₃, have been prepared and characterized by elemental analysis, IR and NMR (¹H, ¹³C and ³¹P) spectroscopic methods. The crystal structure of one of them has been determined by X-ray crystallography. The spectral data of the complexes are consistent with sulfur coordination of the thiones to silver(I). The single crystal X-ray structure of complex 1, {[Ag(PPh₃)(thiourea)(NO₃)]₂·[Ag(PPh₃)(thiourea)]₂(NO₃)₂}, shows that the complex consists of two independent centrosymmetric binuclear units, each having the silver atoms coordinated to one PPh₃ and two bridging thiourea molecules. In one of the independent units the silver atom is additionally bound to a nitrate ion, leading to a tetrahedral geometry, while in the other unit the silver atom adopts a trigonal planar environment. Antimicrobial activities of the complexes were evaluated by their minimum inhibitory concentration and the results showed that the complexes show a wide range of activity against two gram-negative bacteria (Escherichiacoli, Pseudomonasaeruginosa) and molds (Aspergillusniger, Penicilliumcitrinum), while the activities were poor against yeasts (Candidaalbicans, Saccharomycescerevisiae). However, the title complex did not show activity against any tested microorganism.     

Development and evaluation of analytical methodology for the determination of aflatoxins in palm kernels.

A rapid, simple and reproducible method for the simultaneous estimation of aflatoxins AFB1, AFB2, AFG1 and AFG2 in palm kernel samples has been developed by optimizing the sample preparation, solvent extraction, sample clean-up and quantification procedures. The aflatoxins are extracted from a slurried palm kernel sample with an acetone-water (80 + 20, v/v) mixture and the crude extract is cleaned up by solid-phase extraction using a phenyl bonded phase cartridge. The extract is passed through the cartridge with a water-methanol (93 + 7) mixture. Subsequent elution of the aflatoxins retained on the cartridge is achieved with a 3 ml aliquot of chloroform. The aflatoxin content of the eluate is quantified using a bi-directional high-performance thin-layer chromatography procedure. A critical evaluation of the proposed method was carried out by statistical comparison with the British Standard Method. The proposed procedure was shown to be more efficient and precise. Consistent recoveries of over 90% were achieved from spiked palm kernel extracts and detection limits were found to be 3.7, 2.5, 3.0 and 1.3 micrograms kg-1 for AFB1, AFB2, AFG1 and AFG2 aflatoxins, respectively.