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The synthesis, physical nature and spectroscopic characterization, i.e. CHN analyses as well as the IR, 1H-, 13C-, 119Sn NMR and 119mSn Mössbauer spectrometries, of a series of new organotin complexes of N-phthaloylamino acids are described. The monomeric diorganotin complexes possess a trans octahedral geometry. The dimeric tetraorganotin complexes have a penta-coordinate environment. The triphenyltin with N-phthaloylamino acids are assigned a polymeric trigonal bipyramidal geometry in the solid form and a tetrahedral structure in an inert solvent, while tricyclohexyltin with N-phthaloylamino acids complexes possess a tetrahedral geometry. ED50 and biological activities tests were also carried out, which indicated powerful biocidal effects.

An optical pyrometer has been used to measure apparent temperature oscillations during the growth of GaAs/GaAlAs heterostructures by molecular beam epitaxy. The oscillations are due to an optical interference effect in the epitaxial layers and the period can be related to both growth rate and alloy composition. Measurements can be carried out on rotating substrates throughout the deposition cycle of complex device structures, and provide a convenient means of monitoring the uniformity of the deposition process.

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of 1 mm/min. Samples were analyzed under a light microscope to determine the nature of bond failure. Ten samples (2 mm thick) were prepared for all the materials, and Vickers microhardness was determined using a digital hardness tester. Data were analyzed using one-way analysis of variance and Tukey-Kramer multiple comparison tests at a significance level of p < 0.05. Results: Biodentine (42.02; 39.35 MPa) and ProRoot MTA (21.86; 34.13 MPa) showed significantly higher bond strengths than BioAggregate (6.63; 10.09 MPa) in coronal and apical root dentin, respectively ( p < 0.05). Biodentine also differed significantly from ProRoot MTA in coronal dentin. Bond failure was predominantly adhesive in Biodentine and ProRoot MTA, while BioAggregate showed predominantly mixed failure. ProRoot MTA (158.52 HV) showed significantly higher microhardness and BioAggregate (68.79 HV) showed the lowest hardness. Conclusion: Biodentine and ProRoot MTA showed higher bond strength and microhardness compared to BioAggregate. AbstractObjective: This was an in vitro evaluation of push-out bond strength and surface microhardness of calcium silicatebased biomaterials in coronal and apical root dentin. Materials and Methods: Ninety sections (2 mm thick) of coronal and apical root dentin were obtained from roots of 60 extracted teeth; the canals were enlarged to a standardized cavity diameter of 1.3 mm. Sections were randomly divided into 6 groups ( n = 15 per group), and cavities were filled with Biodentine TM , BioAggregate, or ProRoot mineral trioxide aggregate (MTA), according to the manufacturers' instructions. Push-out bond strength values were measured using a universal testing machine under a compressive load at a speed Significance of the StudyIn this study, the push-out bond strength and microhardness of 3 materials, ProRoot MTA, Biodentine, and BioAggregate, were compared. Biodentine and ProRoot MTA had higher bond strength and microhardness values than BioAggregate, and hence could be the materials of choice for root repair procedures and retrograde fillings.

This paper presents a new coverage flight path planning algorithm that finds collision-free, minimum length and flyable paths for unmanned aerial vehicle (UAV) navigation in three-dimensional (3D) urban environments with fixed obstacles for coverage missions. The proposed algorithm significantly reduces computational time, number of turns, and path overlapping while finding a path that passes over all reachable points of an area or volume of interest by using sensor footprints’ sweeps fitting and a sparse waypoint graph in the pathfinding process. We devise a novel footprints’ sweep fitting method considering UAV sensor footprint as coverage unit in the free spaces to achieve maximal coverage with fewer and longer footprints’ sweeps. After footprints’ sweeps fitting, the proposed algorithm determines the visiting sequence of footprints’ sweeps by formulating it as travelling salesman problem (TSP), and ant colony optimization (ACO) algorithm is employed to solve the TSP. Furthermore, we generate a sparse waypoint graph by connecting footprints’ sweeps’ endpoints to obtain a complete coverage flight path. The simulation results obtained from various scenarios fortify the effectiveness of the proposed algorithm and verify the aforementioned claims.

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This paper extends the existing Fisher's equation by adding the source term and generalizing the degree β of the non-linear part. A numerical solution of a modified Fisher's equation for different values of β using the cubic B-spline collocation scheme is also investigated. The fractional derivative in a time dimension is discretized in Caputo's form based on the L1 formula, while cubic B-spline basis functions are used to interpolate the spatial derivative. The non-linear part in the model is linearized by the modified formula. The efficiency of the proposed scheme is examined by simulating four test examples with different initial and boundary conditions. The effect of different parameters is discussed and presented in tables and graphics form. Moreover, by using the Von Neumann stability formula, the proposed scheme is shown to be unconditionally stable. The results of error norms reflect that the present scheme is suitable for non-linear time fractional differential equations.