Focusing Light through Random Photonic Media by Binary Amplitude Modulation

We study the focusing of light through random photonic materials using wavefront shaping. We explore a novel approach namely binary amplitude modulation. To this end, the light incident to a random photonic medium is spatially divided into a number of segments. We identify the segments that give rise to fields that are out of phase with the total field at the intended focus and assign these a zero amplitude, whereas the remaining segments maintain their original amplitude. Using 812 independently controlled segments of light, we find the intensity at the target to be 75 +/- 6 times enhanced over the average intensity behind the sample. We experimentally demonstrate focusing of light through random photonic media using both an amplitude only mode liquid crystal spatial light modulator and a MEMS-based spatial light modulator. Our use of Micro Electro-Mechanical System (MEMS)-based digital micromirror devices for the control of the incident light field opens an avenue to high speed implementations of wavefront shaping

Stability of black carrot anthocyanins in the turkish delight (LOKUM) during storage

In this research, traditional Turkish delight (lokum) was colored with black carrot juice concentrate, and the variations in anthocyanin content, during storage at different temperatures (12, 20 and 30C) for 5-month periods, were observed by spectrophotometer and high-performance liquid chromatography. Analysis of kinetic data suggested a first-order reaction for the degradation of black carrot anthocyanins in Turkish delight. Degradation rates of anthocyanins of black carrot increased with increasing temperature. It was determined that the degradation rate of black carrot anthocyanins during the storage period at 12C increased faster than that of the other temperatures (20 and 30C). The k values for 12, 20 and 30C were found to be 6.91 × 10 -3, 4.21 × 10 -3and 9.21 × 10 -3/day, respectively. Effects of pH on the thermal stability of black carrot anthocyanins were also determined. Results showed that the stability of anthocyanins decreased as the pH value increased. Increase in pH values correlated well with the decrease in anthocyanin content of the samples during storage. In all of the samples, redness (a*) decreased during the storage at all temperatures; however, lightness (L*) increased. PRACTICAL APPLICATIONS Most of commercial anthocyanins used as a colorant in foods are obtained from fruits or vegetables such as: red grape, elderberry, blackcurrant, blackberry, raspberry, black chokeberry, red cabbage, black carrot, purple corn, red radish and purple sweet potato. Turkish delight (lokum), one of the most popular traditional food products in Turkey, is a famous Turkish desert known all over the world. Lokum is produced by using sugar, water, starch, citric acid, aromatic compounds, dried fruits and natural colorant. The color of foods, which is one of the initial properties noticed in foods, is one of the most important quality parameters affecting consumers. Because of consumer anxiety over the safety of synthetic food colorants, the demand for natural food colorants has increased. Particularly, there is an increasing request for natural red food colorants as alternatives to the most commonly used synthetic red colorant. Therefore, the availability and the suitability of black carrot juice concentrate as a natural colorant instead of synthetic colorants which are considered to have some negative properties for human health was investigated by this work. © 2009 Wiley Periodicals, Inc

Scattering Lens Resolves sub-100 nm Structures with Visible Light

The smallest structures that conventional lenses are able to optically resolve are of the order of 200 nm. We introduce a new type of lens that exploits multiple scattering of light to generate a scanning nano-sized optical focus. With an experimental realization of this lens in gallium phosphide we have succeeded to image gold nanoparticles at 97 nm optical resolution. Our work is the first lens that provides a resolution in the nanometer regime at visible wavelengths.Comment: 4 pages, 3 figure

Benchmarking of Different Powder-Bed Metal Fusion Processes for Machine Selection in Additive Manufacturing

In the last decade, additive manufacturing has gained significant interest for direct part production and started to change the way companies manufacture products; even in very demanding sectors like aerospace. The biggest challenge for a wider industrial acceptance still stands as the need for more reliable, repeatable and precise machines for additive manufacturing. This paper presents a comprehensive benchmarking study for the selection of an additive manufacturing machine for powder-bed metal fusion process, i.e. Selective Laser Melting or Direct Metal Laser Sintering or Laser Cusing. Four different machine vendors for the same technology to be employed for aeroengine part manufacturing using Inconel 625 powder have been involved for comparing different machine specifications. Many aspects such as dimensional accuracy, surface quality, need of support structures, density, hardness and process limits (minimum wall thickness, overhang surfaces, inclinations and curvatures, etc.) are addressed in the paper. The state-of-the-art in machines for powder-bed metal fusion process is presented aiming at understanding the current limitations of the technology available today.Mechanical Engineerin

Primary extranodal Non-Hodgkin`s lymphoma presenting as painful gingval swelling

Primary extra-nodal non-Hodgkin’s lymphomas (NHL) constitute 25–40% of NHL but less than 1% arises in oral cavity. Here in 53-year-old man with stage IE gingival diffuse large B cell lymphoma who was treated successfully with chemotherapy and radiotherapy was presented

Exotic Smoothness and Quantum Gravity

Since the first work on exotic smoothness in physics, it was folklore to assume a direct influence of exotic smoothness to quantum gravity. Thus, the negative result of Duston (arXiv:0911.4068) was a surprise. A closer look into the semi-classical approach uncovered the implicit assumption of a close connection between geometry and smoothness structure. But both structures, geometry and smoothness, are independent of each other. In this paper we calculate the "smoothness structure" part of the path integral in quantum gravity assuming that the "sum over geometries" is already given. For that purpose we use the knot surgery of Fintushel and Stern applied to the class E(n) of elliptic surfaces. We mainly focus our attention to the K3 surfaces E(2). Then we assume that every exotic smoothness structure of the K3 surface can be generated by knot or link surgery a la Fintushel and Stern. The results are applied to the calculation of expectation values. Here we discuss the two observables, volume and Wilson loop, for the construction of an exotic 4-manifold using the knot $5_{2}$ and the Whitehead link $Wh$. By using Mostow rigidity, we obtain a topological contribution to the expectation value of the volume. Furthermore we obtain a justification of area quantization.Comment: 16 pages, 1 Figure, 1 Table subm. Class. Quant. Grav

Parabolic oblique derivative problem in generalized Morrey spaces

We study the regularity of the solutions of the oblique derivative problem for linear uniformly parabolic equations with VMO coefficients. We show that if the right-hand side of the parabolic equation belongs to certain generalized Morrey space than the strong solution belongs to the corresponding generalized Sobolev-Morrey space

A novel algorithm for dynamic student profile adaptation based on learning styles

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.E-learning recommendation systems are used to enhance student performance and knowledge by providing tailor- made services based on the students’ preferences and learning styles, which are typically stored in student profiles. For such systems to remain effective, the profiles need to be able to adapt and reflect the students’ changing behaviour. In this paper, we introduce new algorithms that are designed to track student learning behaviour patterns, capture their learning styles, and maintain dynamic student profiles within a recommendation system (RS). This paper also proposes a new method to extract features that characterise student behaviour to identify students’ learning styles with respect to the Felder-Silverman learning style model (FSLSM). In order to test the efficiency of the proposed algorithm, we present a series of experiments that use a dataset of real students to demonstrate how our proposed algorithm can effectively model a dynamic student profile and adapt to different student learning behaviour. The results revealed that the students could effectively increase their learning efficiency and quality for the courses when the learning styles are identified, and proper recommendations are made by using our method

Computing Amplitudes in topological M-theory

We define a topological quantum membrane theory on a seven dimensional manifold of $G_2$ holonomy. We describe in detail the path integral evaluation for membrane geometries given by circle bundles over Riemann surfaces. We show that when the target space is $CY_3\times S^1$ quantum amplitudes of non-local observables of membranes wrapping the circle reduce to the A-model amplitudes. In particular for genus zero we show that our model computes the Gopakumar-Vafa invariants. Moreover, for membranes wrapping calibrated homology spheres in the $CY_3$, we find that the amplitudes of our model are related to Joyce invariants.Comment: 26 page