Optical characterization of a new donor–acceptor type conjugated polymer derived from 3,4-diphenylthiophene

A new donor–acceptor type poly{2-(3,4-didecyloxythiophen-2-yl)-5-[3,4-diphenyl-5-(1,3,4-oxadiazol-2-yl)thiophen-2-yl]-1,3,4-oxadiazole} (P1) has been designed and synthesized starting from thiodiglycolic acid, 1,2-diphenylethane-1,2-dione, and diethyl oxalate through multi-step reactions using precursor polyhydrazide route. The charge-transporting and linear optical property of the polymer has been investigated by cyclic voltammetric, UV–visible, and fluorescence emission spectroscopic studies. The UV–visible absorption spectrum of polymer in thin film form showed maxima at 420 nm. The polymer displayed bluish-green fluorescence both in solution and thin film form. The optical band gap is determined to be 2.27 eV. Third-order nonlinear optical property of the new polymer has been investigated at 532 nm using single beam Z-scan and degenerate four wave mixing (DFWM) techniques with nanosecond laser pulses. The absorptive nonlinearity observed for the polymer P1 is of optical limiting type, which arises due to an “effective” three-photon absorption (3PA) process. The third-order nonlinear optical susceptibility (χ⁽³⁾) of the polymer is found to be 0.831 × 10^–12 esu. Both linear and nonlinear optical studies revealed that the new polymer (P1) is a promising material for applications in photonic devices.     

Identification of the antibiotic phomalactone from the entomopathogenic fungusHirsutella thompsonii var.synnematosa

Dichloromethane extracts of culture broth from three strains of the entomopathogenic fungusHirsutella thompsonii var.synnematosa were toxic to two species of tephritid fruit fly and inhibited conidial germination in vitro in several other entomopathogenic fungi includingBeauveria bassiana, Tolypocladium spp., andMetarhizium anisopliae. A major metabolite, toxic to apple maggot,Rhagoletis pomonella, and inhibitory to conidial germination inB. bassiana, was isolated and identified as the antibiotic (+)-phomalactone, 6-(1-propenyl)-5,-6-dihydro-5-hydroxypyran-2-one. This is the first biologically active compound of low molecular weight isolated from the genusHirsutella.Mention of a commercial or proprietary product does not constitute an endorsement by the USDA.     

SML-Sys: a functional framework with multiple models of computation for modeling heterogeneous system

System-on-Chip and other complex distributed hardware/software systems contain heterogeneous components. High-level modeling of such systems require frameworks that provide designers with the ability to express concepts of models of computation (MoC)s as modeling constructs. Many system-level modeling frameworks and corresponding modeling notations such as Ptolemy II and SystemC-H facilitate multi-MoC modeling but are based on imperative programming languages (C++, Java, etc). In such frameworks, the computation and communication aspects between the components of models get intertwined thereby hindering its amenability to formal analysis. In this work, we illustrate function-based semantic definitions of MoCs, which are formulated in a functional framework called SML-Sys. We illustrate through a number of examples how to create system models using this functional programming paradigm.     

Mining metadata for composability of IPs from SystemC IP library

Exploring the design space when constructing a system is vital to realize a well performing design. Design complexity has made building high-level system models to explore the design space an essential but time-consuming and tedious part of the system design. Reduction in design time and acceleration of design exploration can be provided through reusing IP-cores to construct system models. As a result, it is common to have high-level SoC design flow based on IP libraries promoting reuse. However, the success of these would be dependent on how introspection and reflection capabilities are provided as well as what are the interoperability standard defined. This leads to the important question of what kind of IP metadata must be available to allow CAD tools to effectively manipulate these designs as well as allow for a seamless integration and exchange design information between tools and design flows. In this article, we describe our tools and methodology, which allow introspection of SystemC designs, such that the extracted metadata enables IP composition. We discuss the issues related to extraction of metadata from IPs specified in SystemC and show how our methodology combines C++ and XML parsers and data structures to achieve the above.     

Continuous Flow Microwave‐Assisted Processing and Aseptic Packaging of Purple‐Fleshed Sweetpotato Purees

ABSTRACT: Pumpable purees from purple‐flesh sweetpotatoes (PFSP) were subjected to microwave heating using a 60 kW, 915 MHz continuous flow system, followed by aseptic packaging in flexible containers to obtain a shelf‐stable product. Initial test runs were conducted using a 5 kW 915 MHz microwave system to measure dielectric in‐line properties and examine the puree temperature profiles. The results demonstrated uniformity in heating of the puree at sterilization temperatures (>121 °C), and the dielectric constants and loss factors were within the range of published values for orange‐fleshed sweetpotato purees. The pilot‐scale test runs in a 60 kW microwave unit produced shelf‐stable puree packages stable at room temperature. Polyphenolic content of the PFSP purees were evaluated and the results showed that while total phenolics increased (5.9%) and total monomeric anthocyanins slightly decreased (14.5%) with microwave application, antioxidant activity determined by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC) assays did not significantly change as a result of microwave processing. Color values showed that microwave‐processed samples differed from fresh puree in saturation and hue angle, but not in overall color change. PFSP purees increased in gel strength when microwave processed, packaged, and stored, but the gel could be easily disrupted into flowable purees. Overall, high‐quality retention can be obtained by microwave processing and aseptic packaging of PFSP purees so that they can be used as functional food ingredients.     

Sunflower Acid Oil-Based Production of Rhamnolipid Using Pseudomonas aeruginosa and Its Application in Liquid Detergents

Utilization of industrial waste as substrates for the rhamnolipid synthesis by Pseudomonas aeruginosa is a worthy alternative for conventionally used vegetable oils and fatty acids to reduce the production cost of rhamnolipid. Sunflower acid oil (SAO), a by-product of the oil industry, contains 70% 18:0 fatty acid, with oleic acid as a major component. In this scope, production and analysis of rhamnolipid was successfully demonstrated using SAO as a new substrate. Pseudomonas aeruginosa produced rhamnolipid (a glycolipid biosurfactant) at a maximum concentration of 4.9 g L⁻¹ with 60 g L⁻¹ of SAO in the medium. Structural properties of rhamnolipid biosurfactant are confirmed using thin layer chromatography (TLC), high performance liquid chromatography (HPLC), and fourier transformed infrared spectroscopy (FTIR) analysis. Further surface-active properties of the crude rhamnolipid were evaluated by measuring surface tension and emulsification properties. The synthesized rhamnolipid reduced the surface tension of water to 30.12 mN m⁻¹ and interfacial tension (against heptane) to 0.52 mN m⁻¹. Moreover, rhamnolipid shows the highest emulsification index (above 80%) for vegetable oils. This study confirms the use of SAO as a potential substrate for rhamnolipid production. The synthesized rhamnolipid was incorporated in liquid detergent formulation along with alpha olefin sulfonate (AOS) and sodium lauryl ether sulfate (SLES). The performance properties including foaming and cleaning efficiency of liquid detergent were compared.     

A study on remanufacturing possibility of a product

With the intensification of Globalization, customers’ environment-friendly attitude and stringent environmental regulations, the manufacturers have been orienting their manufacturing and other value additive processes towards the development of more environment-friendly products and use of relevant processes including taking back of used products after their end-of-use or end-of-life from the end users. Remanufacturing is one of the prominent and popular options. Remanufacturing perhaps has drawn maximum attention because of its economic viability and environmental cleanliness. The remanufacturing operation depends upon the quality and quantity of the used. Better the quality lesser the remanufacturing cost. A remanufacturer is unaware about the condition of used product before its acquisition. It may also be noted that the remanufactured product may be taken after a period of its use by users. So it is really difficult to judge how many cycles does the product go for remanufacturing. This has drawn the attention of the authors and the problem is studied with developing some mechanism on the possible frequency of the remanufacturing of a new product. This paper is a study report on this area of research which is expected to contribute immensely to the remanufacturing business.

     

Performance analysis of wireless communication system over nonidentical cascaded generalised gamma fading channels

Multiplicative fading statistics usually encountered in different radio propagation environments. In this context, we evaluate and analyse the performance of a wireless communication system over the nonidentical cascaded generalised Gamma Fading Channels, also known as generalised Bessel‐K fading channel. To this end, the closed‐form expressions for the amount of fading (AOF), the outage probability (OP), the average symbol error probability (SEP), and the channel capacity are derived. In addition approximate expressions for the average SEP with maximal ratio combining (MRC) diversity are also provided. The low‐ and high‐power solutions for the channel capacity are also provided. Furthermore, simplified asymptotic average SEP expressions for MRC and selection combining (SC) are presented to gain the system performance with diversity. The proposed methodologies provide more flexibility to accommodate different radio propagation scenarios. To examine the accuracy of the proposed solutions, numerical and simulation results are compared and shown to fit for variety of fading parameters.