A Novel FRFT Beamformer for Rayleigh Faded Channels

A method of optimal beamforming for flat Rayleigh faded channels using the Fractional Fourier Transform (FRFT) is considered in this paper. It has been demonstrated through simulations that optimal beamforming with FRFT allows smaller mean-square errors in restoring signals degraded with linear time-or frequency variant distortions and Additive White Gaussian Noise. This is made possible by the additional flexibility that comes with free parameter ‘a’ of the fractional Fourier transform as oppose to the classical Fourier transform (FT). The method is especially useful in moving source problems, where Doppler Effect produces frequency shift when the source is moving, as in mobile and wireless communication where user produces the frequency shift while moving. In this paper it is shown through simulations that beamforming in fractional domain reduces BER as compared to time or frequency domain.     

Dietary Components Affect the Plasma and Tissue Levels of Lutein in Aged Rats with Lutein Deficiency—A Repeated Gavage and Dietary Study

The aim of this study was to find out the influence of selected dietary components on plasma and tissue response of repeated micellar and dietary lutein in aged rats with lutein deficiency. In repeated (16 d) gavage study, micellar lutein was co‐ingested with either phosphatidylcholine (PC), lyso‐phosphatidylcholine (lysoPC), β‐carotene, dietary fiber or vegetable fat (3% soybean oil). In dietary study, rats were fed (4 wk) semi‐synthetic diet either with lutein + PC, lutein + dietary fiber or B. alba (lutein source) + PC. The post‐prandial plasma and tissue response of lutein was measured by HPLC. Results showed that micellar fat, PC and lysoPC significantly (P ≤ 0.05) increased the lutein levels in plasma (31.1%, 26.8%, and 34.9%), liver (27.4%, 29.5%, and 8.6%), and eyes (63.5%, 90.2%, and 86%) compared to the control group (group gavaged micelles with no dietary components studied). Similarly, dietary study showed an enhanced plasma, liver, and eye lutein levels by 44.8%, 24.1%, and 42.0% (lutein + PC group) and 51.7%, 39.8%, and 31.7% (B.alba + PC group), respectively compared to control. The activity of antioxidant enzymes in plasma and liver of both the studies were also affected compared to control. Result reveals, that PC enhance the intestinal absorption of both micellar and dietary lutein which is either in free or bound form with food matrices in aged rats with lutein deficiency. Hence, PC at a concentration used in this study can be considered to improve the lutein bioavailability in lutein deficiency.     

CLAMP: Efficient class-based sampling for flexible flow monitoring

With an increasing requirement to classify traffic and track security threats, newer flexible and efficient ways are needed for collecting traffic statistics and monitoring network flows. However, traditional solutions based on packet sampling do not provide the flexibility required for these applications. For example, operators are often interested in observing as many unique flows as possible; however, random packet sampling is inherently biased towards large flows. Operators may also be interested in increasing the fidelity of flow measurements for a certain class of flows; such flexibility is lacking in today’s packet sampling frameworks. In this paper, we propose a novel architecture called CLAMP that provides an efficient framework to implement class-based sampling. At the heart of CLAMP is a novel data structure we propose called composite Bloom filter (CBF) that consists of a set of Bloom filters working together to encapsulate various class definitions. In particular, we show the flexibility and efficacy of CLAMP by implementing a simple two-class size-based sampling. We also consider different objectives such as maximizing flow coverage and improving the accuracy of certain class of flows. In comparison to previous approaches that implement simple size-based sampling, our architecture requires substantially lower amounts of memory (up to 80×) and achieves higher flow coverage (up to 8× more flows) under specific configurations.     

Thiocompounds as simulants of sulphur mustard for testing of protective barriers

The protective potential of protective devices such as respirators, suits, gloves, and overboots is widely evaluated using the standard colorimetric test (spot disc breakthrough time test, also called SD BTT) involving sulfur mustard (SM) as the challenge chemical. The vesicant nature of SM makes the test inconvenient and poses stringent safety demands. Moreover, such tests are allowed only at a limited number of facilities, causing delay in product development and supply. This prompted the present study on the search for suitable SM simulant responsive to SD BTT test. The diffusivities at BTT (D_BTT) of 10 commercially available thiocompounds through butyl rubber (IIR) were compared vis‐a‐vis D_BTT of SM. For three representative thiocompounds, namely methyl (phenyl thio)acetate, 2‐chloroethyl phenyl sulfide (2‐CEPS) and phenyl‐n‐propyl sulfide (PNPS), the transport parameters through IIR were obtained. PNPS and 2‐CEPS were further compared with respect to D_BTT in elastomers such as IIR, ethylene–propylene–diene methylene rubber, polydimethylsiloxane, nitrile rubber, polybutadiene, and natural rubber. 2‐CEPS showed generally same order of D_BTT as SM implying its potential use as a simulant. The transport parameters for various 2‐CEPS/elastomer systems were also determined. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Doping effect of viologen on rectification, charge transport processes and photovoltaic properties of furazano (3,4-b)piperazine thin film device

The electrical and photoelectrical properties of a sandwich junction device based on allyl viologen (AV)-doped furazano (3,4-b)piperazine (FP) having structure ln/AV : FP/ITO have been reported. A significant enhancement in the rectification, dark conductivity and photovoltaic response has been observed in AV-doped FP devices compared with undoped FP devices. The present communication deals with the charge transport mechanism and photogeneration process in ITO/AV doped FP/ln Schottky devices. The J–V characteristics recorded in the dark show a rectification effect due to the formation of a barrier at the AV-doped FP/ln interface. Impedance spectroscopy has been used to study the charge transport mechanism for AV-doped FP and its interface with ln. The bulk and junction resistance along with capacitance were determined by analyzing their contribution at an individual level. Doping imparts an improvement in photoresponse of FP as well as an abundance of photoexcited species at the interface. © 2001 Kluwer Academic Publishers     

Polyoxometalate impregnated carbon systems for the in situ degradation of sulphur mustard

Kinetics of in situ degradation bis-(2-chloroethyl) sulphide (sulphur mustard, HD) on polyoxometalate impregnated carbon systems such as 11-molybdo-1-vanadophosphoric acid (V₁/C), phosphotungstic acid (PTA/C), sodium phosphotungstic acid (PTANa/C), phosphomolybdic acid (PMoA/C), sodium phosphomolybdic acid (PMoANa/C) and silicotungstic acid (SiTA/C) have been studied. These carbons were characterized for micropore volume and surface area by N₂ Brunauer, Emmett and Teller (BET) equation. For degradation studies the solution of HD in chloroform was prepared and taken for the uniform adsorption on the carbon systems using incipient volume. Degradation kinetics was monitored by gas chromatograph equipped with flame ionization detector (GC/FID) and found to be following the pseudo first order kinetics. The values of kinetic rate constant and half-life were calculated. V₁/C system showed the fastest degradation of HD. Hemimustard, thiodiglycol, 1,4-oxathiane, sulphoxide and vinyl-2-chloroethyl sulphide were found to be the degradation products with V₁/C system which indicated the oxidative, hydrolytic and dehydrohalogenation reactions, responsible for HD degradation. Effect of moisture was also studied on most reactive system, i.e., V₁/C. The study indicated that V₁/C can be used as a promising adsorbent system for the degradation of HD.     

Influence of Vegetable Oils on Micellization of Lutein in a Simulated Digestion Model

Lutein and zeaxanthin are selectively accumulated in the macula of the retina, yet their bioavailability is influenced by various dietary factors. Insights regarding the effects of dietary lipids on lutein micellization that is available for absorption are limited. This study investigated the influence of vegetable oils on the relative efficiency of lutein micellization using in vitro digestion procedure. Lutein dispersed in either olive oil (OO), corn oil (CO), soybean oil (SBO), sunflower oil (SFO), groundnut oil (GNO), rice bran oil (RBO) or palm oil (PO) was subjected to simulated gastric and small intestinal digestion. Results showed that the efficiency of micellization of lutein dispersed in olive oil exceeds the other vegetable oils. The percent lutein micellization was in the order of OO > GNO > RBO > SFO > CO > SBO > PO. In comparison, the values for OO were higher than GNO (11%), RBO (18.3%), SFO (19%), CO (21.7%), SBO (30.5%) and PO (35.2%), respectively. These results suggest that OO rich in oleic acid may favor the incorporation of lutein into micelles at the intestinal level. To conclude, the type of vegetable oil in which carotenoids are dispersed is important to achieve an enhanced bioavailable lutein. The correlation between the micellizable lutein and fatty acid composition of vegetable oils are discussed.     

Calorimetric studies of non-isothermal crystallization in amorphous Cu x Ti100−x alloys

The present paper reports the composition dependence of pre-exponential factor and activation energy of non-isothermal crystallization in amorphous alloys of Cu _x Ti_100?x system using differential scanning calorimeter (DSC) technique. The applicability of Meyer-Neldel relation between the pre-exponential factor and activation energy of non-isothermal crystallization for amorphous alloys of Cu-Ti system was verified.