Cooling curve analysis in binary Al-Cu alloys: Part I- Effect of cooling rate and copper content on the eutectic formation

There are many techniques available for investigating the solidification of metals and alloys. In recent years computer-aided cooling curve analysis (CA-CCA) has been used to determine thermo-physical properties of alloys, latent heat and solid fraction. In this study, the effect of cooling rate and copper addition was taken into consideration in non- equilibrium eutectic transformation of binary Al- Cu melt via cooling curve analysis. For this purpose, melts with different copper weight percent of 2.2, 3.7 and 4.8 were prepared and cooled in controlled rates of 0.04 and 0.42 °C/s. Results show that, latent heat of alloy highly depends upon the post- solidification cooling rate and composition. As copper content of alloy and cooling rate increase, achieved nonequilibrium eutectic phase increases that leads to release of high amount of latent heat and appearing of second deviation in cooling curve. This deviation can be seen in first time derivative curve in the form of a definite peak

First-principles study of the effects of gold adsorption on the Al(001) surface properties

In this work, we have studied theoretically the effects of gold adsorption on the Al(001) surface, using {\it ab initio} pseudo-potential method in the framework of the density functional theory. Having found the hollow sites at the Al(001) surface as the most preferred adsorption sites, we have investigated the effects of the Au adsorption with different coverages ($\Theta$=0.11, 0.25, 0.50, 0.75, 1.00 ML) on the geometry, adsorption energy, surface dipole moment, and the work-function of the Al(001) surface. The results show that, even though the work-function of the Al substrate increases with the Au coverage, the surface dipole moment decreases with the changes in coverage from $\Theta=0.11$ ML to $\Theta=0.25$ ML. We have explained this behavior by analyzing the electronic and ionic charge distributions. Furthermore, by studying the diffusion of Au atoms in to the substrate, we have shown that at room temperature the diffusion rate of Au atoms in to the substrate is negligible but, increasing the temperature to about 200$^\circ$ C the Au atoms significantly diffuse in to the substrate, in agreement with the experiment.Comment: 19 pages, 9 eps figure

Further observations on SIMON and SPECK families of block ciphers

SIMON and SPECK families of block ciphers are well-known lightweight ciphers designed by NSA. In this note, based on the previous investigations on SIMON, a closed formula for the squared correlations and differential probabilities of the mapping $\phi(x) = x \odot S^1(x)$ on $\mathbb{F}_2^n$ is given. From the aspects of linear and differential cryptanalysis, this mapping is equivalent to the core quadratic mapping of SIMON via rearrangement of coordinates and EA-equivalence. Based upon the proposed explicit formula, a full description of DDT and LAT of $\phi$ is provided. In the case of SPECK, as the only nonlinear operation in this family of ciphers is, addition mod $2^n$, after reformulating the formula for linear and differential probabilities of addition mod $2^n$, straightforward algorithms for finding the output masks with maximum squared correlation, given the input masks as well as the output differences with maximum differential probability, given the input differences, are presented

The comparative perspective of phytochemistry and biological properties of the Apiaceae family plants

Despite the availability of numerous reports on the discovery of medicinal plant compounds and their properties, one may encounter contradictory results released by these reports at the level of plant families and even within species. To establish an accurate perspective of the Apiaceae family, this study examined the fruit essential oil and methanolic extract of wild and common species of this family. According to the measurement of the antioxidant property in the methanolic extract of the fruits using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, Ferula gummosa, Pimpinella anisum and Cuminum cyminum have high power in inhibiting free radicals. However, Bunium persicum had the strongest DPPH radicals inhibitory potential among all essential oils. The results of antimicrobial tests and their classification analysis showed that C. cyminum and B. persicum fruit essential oil with a high amount of cuminaldehyde had the most antibacterial properties. At the same time, the antifungal properties of H. persicum essential oil (rich in aliphatic ester) were stronger than those of the all the studied plants. Also, the essential oils of F. gummosa and Kelussia odoratissima had favourable antimicrobial properties compared to other studied plants. The investigation of the bacterial structure by scanning electron microscope confirmed the effect of the applied essential oils dose and their antibacterial potential. In general, for the first time, this paper determined the biological values of the fruit essential oil of some wild plants, such as K. odoratissima and H. persicum. Besides, in vitro examination and the mathematical models provided a suitable classification, which makes a comprehensive view in terms of the properties of the Apiaceae family

Comparison of the corneal power measurements with the TMS4-topographer, pentacam HR, IOL master, and javal keratometer

Purpose: The aim was to compare the corneal curvature and power measured with a corneal topographer, Scheimpflug camera, optical biometer, and Javal keratometer. Materials and Methods: A total of 76 myopic individuals who were candidates for photorefractive keratectomy were selected in a cross-sectional study. Manual keratometry (Javal Schiotz type; Haag-Streit AG, Koeniz, Switzerland), automated keratometry (IOL Master version 3.02, Carl Zeiss Meditec, Jena, Germany), topography (TMS4, Tomey, Erlangen, Germany), and Pentacam HR (Oculus, Wetzlar, Germany) were performed for all participants. The 95 limits of agreement (LOAs) were reported to evaluate the agreement between devices. Results: The mean corneal power measurements were 44.3 ± 1.59, 44.25 ± 1.59, 43.68 ± 1.44, and 44.31 ± 1.61 D with a Javal keratometer, TMS4-topographer, the Pentacam and IOL Master respectively. Only the IOL Master showed no significant difference with Javal keratometer in measuring the corneal power (P = 0.965). The correlations of the Javal keratometer with TMS4-topography, Pentacam, and IOL Master was 0.991. 0.982, and 0.993 respectively. The 95 LOAs of the Javal keratometer with TMS4-topography, Pentacam, and IOL Master were - 0.361 to 0.49, -0.01 to 1.14, and - 0.36 to 0.36 D, respectively. Conclusion: Although the correlation of Pentacam, TMS4-topography, IOL Master, and Javal keratometer in measuring keratometry was high, only the IOL Master showed no significant difference with the Javal keratometer. The IOL Master had the best agreement with Javal keratometry

3D Curvelet-Based Segmentation and Quantification of Drusen in Optical Coherence Tomography Images

Spectral-Domain Optical Coherence Tomography (SD-OCT) is a widely used interferometric diagnostic technique in ophthalmology that provides novel in vivo information of depth-resolved inner and outer retinal structures. This imaging modality can assist clinicians in monitoring the progression of Age-related Macular Degeneration (AMD) by providing high-resolution visualization of drusen. Quantitative tools for assessing drusen volume that are indicative of AMD progression may lead to appropriate metrics for selecting treatment protocols. To address this need, a fully automated algorithm was developed to segment drusen area and volume from SD-OCT images. The proposed algorithm consists of three parts: (1) preprocessing, which includes creating binary mask and removing possible highly reflective posterior hyaloid that is used in accurate detection of inner segment/outer segment (IS/OS) junction layer and Bruch’s membrane (BM) retinal layers; (2) coarse segmentation, in which 3D curvelet transform and graph theory are employed to get the possible candidate drusenoid regions; (3) fine segmentation, in which morphological operators are used to remove falsely extracted elongated structures and get the refined segmentation results. The proposed method was evaluated in 20 publically available volumetric scans acquired by using Bioptigen spectral-domain ophthalmic imaging system. The average true positive and false positive volume fractions (TPVF and FPVF) for the segmentation of drusenoid regions were found to be 89.15% ± 3.76 and 0.17% ± .18%, respectively

Lai-Massey Scheme Revisited

Lai-Massey scheme is a well-known block cipher structure which has been used in the design of the ciphers PES, IDEA, WIDEA, FOX and MESH. Recently, the lightweight block cipher FLY applied this structure in the construction of a lightweight $8 \times 8$ S-box from $4 \times 4$ ones. In the current paper, firstly we investigate the linear, differential and algebraic properties of the general form of S-boxes used in FLY, mathematically. Then, based on this study, a new cipher structure is proposed which we call generalized Lai-Massey scheme or GLM. We give upper bounds for the maximum average differential probability (MADP) and maximum average linear hull (MALH) of GLM and after examination of impossible differentials and zero-correlations of one round of this structure, we show that two rounds of GLM do not have any structural impossible differentials or zero-correlations. As a measure of structural security, we prove the pseudo-randomness of GLM by the H-coefficient method

Quantum teleportation with nonclassical correlated states in noninertial frames

Quantum teleportation is studied in noninertial frame, for fermionic case, when Alice and Bob share a general nonclassical correlated state. In noninertial frames two fidelities of teleportation are given. It is found that the average fidelity of teleportation from a separable and nonclassical correlated state is increasing with the amount of nonclassical correlation of the state. However, for any particular nonclassical correlated state, the fidelity of teleportation decreases by increasing the acceleration.Comment: 10 pages, 3 figures, expanded version to appear in Quantum Inf. Proces