Frequency selective surfaces comprised of periodic arrays of two-turn square spiral shaped conductors

The scattering of electromagnetic waves from a frequency selective surfaces (FSSs) composed of a new two-turn square spiral shaped periodic structures are investigated by using modal expansion method. The moment method of Galerkin type is employed by expressing the current induced on the metallic surfaces in terms of Piecewise Sinusoidal (PWS) basis functions to determine the FSS structure reflection and transmission coefficients.     

LMF-aware Web services for accessing semantic lexicons

This paper demonstrates that Wordnet-LMF, a version of ISO LMF, allows us to effectively design and implement Web services for accessing WordNet-type semantic lexicons that conform to the REST Web service architecture. The implemented prototype service currently provides access to native wordnets as well as to a bilingual concept dictionary. This paper thus describes slight revisions that were made to the Wordnet-LMF specifications to model and accommodate a non-wordnet-native bilingual concept dictionary.     

Improved reconfigurability and noise margins in threshold logic gates via back-gate biasing in DG-MOSFETs

We present a compact and error tolerant implementation of reconfigurable threshold logic gates (TLG) based on nanoscale DG-MOSFET transistors. The use of independently driven double-gate (IDDG) MOSFETs to build a TLG leads not only to fine-grain reconfigurability by way of voltage-adjustable threshold level (T), but also allows one to vary input weights (w _i ) or reduce number of inputs (x _i ), depending on the design preferences. Operation of the proposed TLG circuits is verified using UFDG SPICE model, and design trade-offs in terms of size, functionality and performance are also indicated. We show that IDDG MOSFETs lead to more efficient and compact TLG circuits that have better design latitude and noise immunity than the conventional counterparts, while also improving the overall reconfigurability. When the back-gate dynamic threshold adjustment afforded by the ultra-thin (<10 nm) DG-MOSFETs on SOI substrates is properly understood and utilized, similar to the floating-gate logic architectures, it can be effectively harnessed to create reconfigurability beyond T and can simplify TLG circuit design.     

The microstructural control of cast and mechanical properties of zinc-aluminium alloys

The zinc-aluminium alloys containing 8, 12, and 27% aluminium are finding increasing applications in the casting industry. These alloys are stronger than most aluminium alloys. In addition, they possess high wear resistance and bearing properties. However, surface sinks and shrinkage defects are observed on the bottom faces of such castings, contrary to general foundry practice. In the present investigation, this problem observed in the Zn-8%Al, Zn-12%Al, Zn-27%Al alloys was tackled by controlling various casting parameters and also by additions of the master alloys of strontium and lithium into the molten alloys. It was found that the underside shrinkage problem was influenced by the aluminium content of the alloy, melt superheat, casting size and cooling conditions. The strontium and lithium additions were found to be beneficial in reducing the underside shrinkage problem. The ultimate tensile strength, fracture elongation and Vickers hardness were all increased with aluminium concentration and lithium addition. It was found also that the most problematical Zn-27%Al alloy, which provided the highest mechanical properties, was very suitable for the squeeze-casting technique. The mechanical properties were increased sharply in these squeeze-cast bars.     

Partitioning characteristics of targeted heavy metals in IZAYDAS hazardous waste incinerator

Partitioning of eight targeted heavy metals (Cr, Mn, Cu, Pb, Sn, Co, Ni and Zn) was carried out during five trial burns in Izmit hazardous and clinical waste incinerator (IZAYDAS). Metal contents of the original wastes and their concentration in the bottom ash (BA), fly ash (FA), filter cake (FC) and flue gas were determined. Partitioning behavior of metals during the two-stage incineration was evaluated with respect to physico-chemical properties of feed waste and metals, and the operational conditions. Results suggest that combustion temperatures and retention times are the dominant parameters determining the volatility of metals in the first combustion chamber. Targeted metals were generally partitioned in the rank of bottom ash, filter cake, fly ash and flue gas. High filter cake/fly ash ratios showed that high temperatures in the second stage increase both the formation of gaseous metallic compounds and the enrichment of metals in fine particles. Since ESP could not be effective in removing fine particles and volatilized metallic compounds, the necessity of an additional system that would remove heavy metals efficiently was emphasized for the modern incinerators.     

Characterization of crude lipoxygenase extract from green pea using a modified spectrophotometric method

In the spectrophotometric assay of lipoxygenase (LOX), the buffered linoleic acid solution used as the reaction medium is not optically clear enough at neutral or lower pH values, due to its limited solubility, to provide a precise, accurate and reproducible estimation of activity as the increase in absorbance at 234 nm. Therefore, an optically clear solution was obtained by formation of the Na-salt of unreacted linoleic acid before absorbance measurement. The modified method was then used to characterize crude LOX from green peas in terms of pH and temperature optima, thermal stability, and kinetic parameters. The optimum pH and temperature for the activity of LOX from green peas were determined to be 6.0 and 30 °C, respectively. LOX was found to be very stable at 60 °C, but much less stable at 65 °C or higher temperatures. The Michaelis constant (K_m) and maximum rate (V_max) for linoleic acid were calculated to be 1666 units per mg protein per min and 2.33 mM, respectively.     

Activation of Manganese Ions in Lithium-ion Battery Anode Materials via Nickel and Cobalt Doping

Nanosized Ni_xMn_3?xO_z(x?=?0, 0.25, 0.50, 0.65, 0.75 and 1.0) and (1?y)Li₂MnO₃???(y)LiCoO₂ (y?=?0, 0.1, 0.25, 0.50 and 1.0) powders were synthesized by the Pechini process and electrochemically evaluated as battery anode materials for their lithium capacities and cycle life. The materials were investigated using x-ray diffraction (XRD), a scanning electron microscope (SEM) and electrochemical characterizations. Undoped anode materials (i.e., Mn₂O₃ when x?=?0 and Li₂MnO₃ when y?=?0) had the lowest first cycle Coulombic efficiencies and long-term cycling capacities. However, upon addition of Ni or Co elements, drastic improvements in battery performance was observed. The highest percentages of increase in first cycle performance were observed at an intermediate level of doping (i.e., x?=?0.25 or 0.50 and y?=?0.1 or 0.25). For extended cycling, on the other hand, anode materials with higher levels of nickel and cobalt doping are the best.     

The structural degradation and lamellar to rod transition in the Bi-Cd eutectic during unidirectional growth

The Bi-Cd eutectic system is a prototype quasi-regular eutectic in which the bismuth-rich phase has a volume fraction of 57%. It shows a high degree of regularity but, clearly, is not a normal (regular) eutectic. Microstructural observations of unidirectionally-grown specimens show that the minor cadmium-rich phase degrades at small temperature gradients and small growth rates. However, the structural refinement resulting from rapid freezing or chemical addition is found to be analogous to that of the F/NF eutectics. A lamellar rod transition has been achieved at intermediate growth rates by adding 2.0 wt % Sn as a modifier to the eutectic alloy. However, this was accompanied by the bismuth phase showing cellular facets of the solid-liquid interface.Nomenclature G _L temperature gradient in the melt ahead of the solid/liquid interface (° C cm^–1) - G _S temperature gradient in the solid behind the solid-liquid interface (° C cm^–1) - R growth rate of solid (cm sec^–1) - S cooling rate (° C sec^–1, ° C h^–1) - K _S thermal conductivity in the solid (W m^–1 K^–1) - K _L thermal conductivity in the melt (W m^–1 K^–1) - L latent heat of fusion (J mol^–1) - T temperature difference, undercooling (° C) - K ₁ constant in Equation 2 - K ₂ constant in Equation 3 - D diffusion coefficient of solute in solid (m² sec^–1) - C solubility in solid (wt %, at %) - M molecular weight (g mol^–1) - density (g cm^–3) - interfacial energy, surface tension (J mm^–2) - R gas constant, 8.314J mol^–1 K^–1 - r radius of curvature (m) - T temperature (K) - t time (sec) - F faceted - NF non-faceted     

Multi-Keyword search over encrypted data with scoring and search pattern obfuscation

Search over encrypted data recently became a critical operation that raised a considerable amount of interest in both academia and industry. Especially, as outsourcing, sensitive data to cloud prove to be a strong trend to benefit from the unmatched storage and computing capacities thereof. Indeed, privacy-preserving search over encrypted data, an apt term to address privacy-related issues concomitant in outsourcing sensitive data, have been widely investigated in the literature under different models and assumptions. In this work, we propose an efficient scheme that allows privacy-preserving search over encrypted data using queries with multiple keywords. Most important contributions of this work are as follows. Firstly, using a property referred as \(\delta \)-mean query obfuscation, the proposed scheme hides the search patterns, which are allowed to leak in many works in the literature including our preliminary work on the subject Orencik et al. (2013) [1]. Secondly, a two-server setting is employed to eliminate the correlation between the queries and matching documents sent to the user under the assumption that the two servers are not colluding. Thirdly, we propose a novel compression scheme that reduces both the communication cost between the two servers and the computation cost of the search operation more than 55 times compared to the standard approach. And finally, the proposed scheme also provides an effective scoring and ranking capability that is based on term frequency–inverse document frequency (tf-idf) weights of keyword–document pairs. Our analyses demonstrate that the proposed scheme is privacy-preserving, efficient and effective.