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An efficient methodology for the synthesis of 1,3-thiazolidin-4-ones using L-Proline as catalyst under aqueous conditions has been developed. The one-pot, multicomponent reaction of aromatic/heterocyclic aldehyde, aromatic amine and thioglycolic acid at room temperature give 1,3-thiazolidin-4-ones in moderate to good yields. Further, the current approach is notably greener than traditional methods with E-factor of 3.1 and the eco scale score of 96. The developed protocol offers several features, such as being simple, environmentally benign, energy-efficient, economical, mild conditions, shorter reaction time.

A parametric comparison study is carried out between segmented and conventional continuous layer configurations of the coated combustion-catalyst to investigate their influence on the performance of methane steam reforming (MSR) for hydrogen production in a catalytic plate reactor (CPR). MSR is simulated on one side of a thin plate over a continuous layer of nickel-alumina catalyst by implementing an experimentally validated surface microkinetic model. Required thermal energy for the MSR reaction is supplied by simulating catalytic methane combustion (CMC) on the opposite side of the plate over segmented and continuous layer of a platinum-alumina catalyst by implementing power law rate model. The simulation results of both coating configurations of the combustion-catalyst are compared using the following parameters: (1) co-flow and counter-flow modes between CMC and MSR, (2) gas hourly space velocity and (3) reforming-catalyst thickness. The study explains why CPR designed with the segmented combustion-catalyst and co-flow mode shows superior performance not only in terms of high hydrogen production but also in terms of minimizing the maximum reactor plate temperature and thermal hot-spots. The study shows that the segmented coating requires 7% to 8% less combustion-side feed flow and 70% less combustion-catalyst to produce the required flow of hydrogen (29.80 mol/h) on the reforming-side to feed a 1 kW fuel-cell compared to the conventional continuous coating of the combustion-catalyst.

Alzheimer's disease (AD) is a neurodegenerative disease majorly affecting old age populations. Various factors that affect the progression of the disease include, amyloid plaque formation, neurofibrillary tangles, inflammation, oxidative stress, etc. Herein we report of a new series of substituted (2-aminothiazol-5-yl)(imidazo[1,2-a]pyridin-3-yl)methanones. The designed compounds were synthesized and characterized by spectral data. In vivo anti-inflammatory activity was carried out for screening of anti-inflammatory potential of synthesized compounds. All the compounds were tested for acute inflammatory activity by using carrageenan induced acute inflammation model. Compounds 10b, 10c, and 10o had shown promising acute anti-inflammatory activity and they were further tested for formalin induced chronic inflammation model. Compound 10c showed both acute and chronic anti-inflammatory activity. Compound 10c also showed promising results in AlCl3 induced AD model. Studies on various behavioral parameters suggested improved amnesic performance of compound 10c treated rats. Compound 10c treated rats also exhibited excellent antioxidant and neuroprotective effect with inherent gastrointestinal safety.

Pyrimidine derivatives are well-known nitrogen containing heterocyclic compound which play an important role in medicinal and pharmaceutical applications. The synthesized compound, 2-chloro-4-(4-fluoro-phenyl)-6-isopropyl-pyrimidine-5-carboxylic acid methyl ester has been confirmed by single crystal X-ray diffraction studies. Title compound crystallizes in monoclinic space group P21/c with a = 8.5272(11) A, b = 17.774(2) A, c = 10.2732(14) A, β = 111.005(2)° and Z = 4. The number of weak but significant C–H···O, C–H···N, C–F···π and π–π interactions take part, in the stability of the crystal packing and also the quantitative contributions of these interactions towards the crystal packing are investigated by Hirshfeld surface analysis. A static disorders have been observed in isopropyl substituent group of atoms C20 and C21 due to anisotropic thermal motion. Ab-initio and Density Functional Theory (DFT) calculations have been carried out for the title molecule using RHF/6-311G and B3LYP/6-311G basis set respectively without polarization function, predicting the optimized geometry which can well reproduce structural parameters. Mullikan charge distributions conforms the role of specific atom especially the donor/acceptor groups in the intermolecular interactions. In the present study, the neutral chlorine Cl (Mullikan charge is 0.0038 and 0.0256 by RHF and B3LYP respectively) does not take part in intermolecular interaction, whereas fluorine F (Mullikan charge is −0.4358 and −0.3319 by RHF and B3LYP respectively) took active part in intermolecular interactions. The calculated HOMO and LUMO energies show that charge transfer occur in the molecule. To investigate the effect of different substituted groups on molecular conformation and hence on its pharmacology, the title compound redesigned with different halogens replacing fluorine of fluoro-phenyl ring and docked with human estrogen receptor (2IOK) and attempted to predict the best drug. The molecular structure of 2-chloro-4-(4-fluro-phenyl)-6-isopropyl-pyrimidine-5-carboxylic acid methyl ester has been determine, weak but significant interactions like C–H···O, C–H···F and π–π are involved in the stability of the structure and the quantitative contributions of these interactions towards the crystal packing are investigated by Hirshfeld surface analysis.

The main driving force for High Operating Temperature (HOT) detectors is the strong need for low cost, compact IR imaging solution capable of supporting a wide range of military and civilian applications. In the HOT regime where imagers can be cooled with multi-stage thermoelectric coolers, the major portion of the cost is due to the die-level back-end process, from the chip hybridization to final packaging. We present here an approach to achieve significant cost reduction of MWIR imagers by monolithically integrating III-V devices directly on Silicon substrates for wafer-scale fabrication and packaging of focal plane arrays (FPAs). High quality InAs films can be grown on a blanket Silicon wafer by metal-organic chemical vapor deposition (MOCVD) in a low growth temperature regime that complies with the thermal budget of the Si-electronics. High Resolution Transmission Electron Microscopy reveals predominantly oriented, single-crystal-like InAs films, with Σ3(111) twin boundaries, which our band structure calculations predict to be electrically benign. More intriguingly, selective-area growth on SiO2-masked ROIC-like templates is demonstrated with single-crystal-like InAs film nucleation at small Si(001) openings, together with the suppression of unwanted deposition on the dielectric mask. High crystallinity lateral epitaxial overgrowth of the InAs islands and film coalescence is achieved, enabling the potential to fully cover the entire patterned substrate. MBE-grown MWIR devices (λcut-off = 4.1 μm) on blanket InAs/Si templates exhibit a dark current of 2x10-5 A/cm2 , a specific detectivity of 6x1011 Jones and a quantum efficiency (QE) above 60% at 100K. The QE remains constant at high temperatures (

Alzheimer's disease (AD) is associated with multiple neuropathological events including β-site amyloid precursor protein cleaving enzyme-1 (BACE-1) inhibition and neuronal inflammation, ensuing degeneracy, and death to neuronal cells. Targeting such a complex disease via a single target directed treatment was found to be inefficacious. Hence, with an intention to incorporate multiple therapeutic effects within a single molecule, multitarget-directed ligands (MTDLs) have been evolved. Herein, for the first time, we report the discovery of novel thiazolyl-thiadiazines that can serve as MTDLs as evident from the in vitro and in vivo studies. These MTDLs exhibited BACE-1 inhibition down to micromolar range, and results from the in vivo studies demonstrated efficient anti-inflammatory activity with inherent gastrointestinal safety. Moreover, compound 6d unveiled noteworthy antioxidant, antiamyloid, neuroprotective, and antiamnesic properties. Overall, results of the present study manifest the potential outcome of thiazolyl-thiadiazines for AD treatment.

Different contents of mandelic acid (2.5–10 %) were mixed with glycerol-plasticized soy protein isolate (SPI) to prepare mandelic acid incorporated soy protein isolate films. The effects of the mandelic acid content on the morphology and properties of the glycerol-plasticized SPI films were investigated by scanning electron microscopy, dynamic mechanical thermal analysis, differential scanning calorimetry, thermogravimetric analysis, water resistivity and tensile testing. The tensile strength of the mandelic acid incorporated SPI films decreased while elongation at break increased. The results indicated that, at 10 mass% of mandelic acid, strong interactions occurred both between the mandelic acid and the SPI matrix, leading to appearance of endotherms at 148.8 °C. Mandelic acid-incorporated soy protein films were also tested for their antibacterial properties.

We report a rapid one-step immunoassay to detect protein using antibody conjugated gold nanoparticles (AbGNPs) where the targeted protein concentration was determined by analyzing the gold nanoparticle aggregation caused by antibody–antigen interactions using nanoparticles tracking analysis (NTA) technique. The sandwich structure constituting the binding of the targeted human IgG to the gold nanoparticle conjugates with goat anti human monoclonal IgG (AbGNPs) was confirmed by transmission electron microscopy. The binding of human IgG (antigen, mentioned hence forth as AT) induce AbGNPs to form dimers or trimers through a typical antibody–antigen–antibody sandwich structure that can be analyzed for the sensitive determination on the basis of change in hydrodynamic diameter of AbGNPs. By this method the minimum detectable concentration of AT is found to be below 2 pg/ml. We expect that a significant change in the hydrodynamic diameter of AbGNP could form the basis for the rapid one-step immunoassay development.

This article describes the results of an investigation on the influence of loading silane treated sugar cane bagasse (SB) on the morphology and properties of recycled polypropylene (rPP). The samples are prepared through melt extrusion followed by injection moulding. The Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) results show that SB-rPP composites have a fairly strong interfacial interaction and a change in crystallization for the highest containing SB composite, however, some fibre pull-outs are observed as the SB content is increased. The interaction influences the thermal and mechanical properties of the samples in a complex way. There are strong indications of a stronger interfacial interaction on the highest containing SB composite, which is supposedly accountable for the increased crystallinity and melting temperature.

We describe our recent results in developing and maturing small pixel (5μm pitch), high definition (HD) mid-wave infrared (MWIR) detector technology as well as focal-plane-array (FPA) hybrids, and prototype 2.4 Megapixel camera development operating at high temperature with low dark current and high operability. Advances in detector performance over the last several years have enabled III-V high operating temperature (T≥150K), unipolar detectors to emerge as an attractive alternative to HgCdTe detectors. The relative ease of processing the materials into large-format, small-pitch FPAs offers a cost-effective solution for tactical imaging applications in the MWIR band. In addition, small pixel detector technology enables a reduction in size of the system components, from the detector and ROIC chips to the focal length of the optics and lens size, resulting in an overall compactness of the sensor package, cooling and associated electronics. An MBE system has been used to grow antimony-based detector structures with 5.1μm cutoff with low total thickness variation (TTV) across a 3” wafer, in order to realize high interconnect yield for small-pitch FPAs. A unique indium bump scheme is proposed to realize 5μm pitch arrays with high connectivity yield. Several 1kx2k /5μm hybrids have been fabricated using Cyan’s CS3 ROICs with proper backend processing and finally packaged into a portable Dewar camera. The FPA radiometric result is showing low median dark current of 2.3x10 -5 A/cm 2 with > 99.9% operability, and >60% QE (without AR coating).

Barrier detectors based on III-V materials have recently been developed to realize substantial improvements in the performance of mid-wave infrared (MWIR) detectors, enabling FPA performance at high operating temperatures. The relative ease of processing the III-V materials into large-format, small-pitch FPAs offers a cost-effective solution for tactical imaging applications in the MWIR band as an attractive alternative to HgCdTe detectors. In addition, small pixel (5-10μm pitch) detector technology enables a reduction in size of the system components, from the detector and ROIC chips to the focal length of the optics and lens size, resulting in an overall compactness of the sensor package, cooling and associated electronics. To exploit the substantial cost advantages, scalability to larger format (2kx2k/10μm) and superior wafer quality of large-area GaAs substrates, we have fabricated antimony based III-V bulk detectors that were metamorphically grown by MBE on GaAs substrates. The electro-optical characterization of fabricated 2kx2k/10μm FPAs shows low median dark current (3 x 10-5 A/cm2 with λco = 5.11μm or 2.2 x 10-6 A/cm2 with λco = 4.6μm) at 150K, high NEdT operability (3x median value) >99.8% and >60% quantum efficiency (non-ARC). In addition, we report our initial result in developing small pixel (5μm pitch), high definition (HD) MWIR detector technology based on superlattice III-V absorbing layers grown by MBE on GaSb substrates. The FPA radiometric result is showing low median dark current (6.3 x 10-6 A/cm2 at 150K with λco = 5.0μm) with ~50% quantum efficiency (non-ARC), and low NEdT of 20mK (with averaging) at 150K. The detector and FPA test results that validate the viability of Sb-based bulk and superlattice high operating temperature MWIR FPA technology will be discussed during the presentation.

Recent advances in superlattice-based infrared detectors have rendered this material system a solid alternative to HgCdTe for dual-band sensing applications. In particular, superlattices are attractive from a manufacturing perspective as the epitaxial wafers can be grown with a high degree of lateral uniformity, low macroscopic defect densities (< 50 cm-2) and achieve dark current levels comparable to HgCdTe detectors. In this paper, we will describe our recent effort on the VISTA program towards producing HD-format (1280x720, 12 μm pitch) superlattice based, dual-band MWIR/LWIR FPAs. We will report results from several multi-wafer fabrication lots of 1280x720, 12 μm pitch FPAs processed over the last two years. To assess the FPA performance, noise equivalent temperature difference (NETD) measurements were conducted at 80K, f/4.21 and using a blackbody range of 22°C to 32°C. For the MWIR band, the NETD was 27.44 mK with a 3x median NETD operability of 99.40%. For the LWIR band, the median NETD was 27.62 mK with a 3x median operability of 99.09%. Over the course of the VISTA program, HRL fabricated over 30 FPAs with similar NETDs and operabilities in excess of 99% for both bands, demonstrating the manufacturability and high uniformity of III-V superlattices. We will also present additional characterization results including blinkers, spatial stability, modulation transfer function and thermal cycles reliability.

Polylactic acid (PLA) is a compostable and biodegradable polymer obtained from renewable resources. They can be used in the packaging and medical industries. For our study, two grades of PLA resins were procured. One grade was procured from Cereplast, Inc., USA, (CPL) and other from NatureWorks LLC, USA, (NWPL). Mechanical, thermal, thermomechanical and morphological studies were carried out for PLA resins procured from both the sources. Virgin and modified canola oil (0.25–0.5% with respect to PLA) were mixed manually with CPL and NWPL to prepare injection-moulded specimens. Mechanical, thermal, thermomechanical and morphological studies of injection moulded PLA samples in the presence of canola oil were then carried out. Results indicated that canola oil acted as a plasticizer for PLA specimens. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.

Alzheimer’s disease (AD) is the most prevalent disease of old age leading to dementia. Complex AD pathogenesis involves multiple factors viz. amyloid plaque formation, neurofibrillary tangles and inflammation. Herein we report of a new series of quinoxaline-bisthiazoles as multitarget-directed ligands (MTDLs) targeting BACE-1 and inflammation concurrently. Virtual screening of a library of novel quinoxaline-bisthiazoles was performed by docking studies. The most active molecules from the docking library were taken up for synthesis and characterized by spectral data. Compounds 8a-8n showed BACE-1 inhibition in micro molar range. One of the compounds, 8n showed BACE-1 inhibition at IC50 of 3 ± 0.07 µM. Rat paw edema inhibition in acute and chronic models of inflammation were obtained at 69 ± 0.45% and 55 ± 0.7%, respectively. Compound 8n also showed noteworthy results in AlCl3 induced AD model. The treated rats exhibited excellent antiamnesic, antiamyloid, antioxidant, and neuroprotective properties. Behavioural parameters suggested improved cognitive functions which further validates the testimony of present study. Moreover, compound 8n was found to have inherent gastrointestinal safety. This new string of quinoxaline-bisthiazoles were identified as effective lead for the generation of potent MTDLs and compound 8n was found to showcase qualities to tackle AD pathogenesis.

The article reports on the successful processing of flax-reinforced poly(lactic acid) (PLA) profiles by thermoplastic pultrusion into ‘sandwich’ structures consisting of commingled yarns as outer layers and layers of nonwoven material in the core section. The results showed that a good quality matrix impregnation was obtained. The profiles produced from only commingled yarns had higher impact strengths due to yarns in the middle of the profiles; the matrix of which did not melt during pultrusion. The flexural properties of the composites improved with increasing nonwoven layers. Good PLA impregnation improved the flexural properties. The tensile strength of the ‘sandwich’ structures was much lower than that of commingled yarn-based composites, this being attributed to the poor distribution of flax fibres and poor interfacial adhesion leading to poor stress transfer from matrix to fibres. Crystallinity decreased as the number of nonwoven layers increased presumably due to blockage of nucleating sites essential for crystal growth. The storage modulus of composites reinforced with commingled yarns was greater than that of the composites reinforced with ‘sandwich’ material, confirming effective transfer of stress from matrix to the commingled flax yarns and indicating that increasing nonwoven layers decreased adhesion between reinforcement and the matrix. The effects of a wide range of pultrusion process parameters on the mechanical properties of resulting profiles were investigated. Higher die temperatures (290°C) and lower pulling speeds (0.5 m min−1) improved the mechanical properties due to better melting and lower viscosity of the matrix, enabling increased penetration within the reinforcement. Flexural and tensile properties of microwave-heated samples were very low due to fibre degradation. Scanning electron microscopic images showed that fibre impregnation was good in ‘sandwich’ systems, but fibre distribution remained a challenge.

Growing cells on 3D scaffolds is far superior to the conventional 2D monolayer culture method. In this study, a novel 3D thermoresponsive poly(propylene-g-N-isopropylacrylamide) (PP-g-PNIPAAm) non-woven fabric (gNWF) was developed for cell culture using oxyfluorination-assisted graft polymerisation (OAGP). New polar functional groups were detected on the oxyfluorinated NWF (oNWF), and PNIPAAm was confirmed in the gNWF by attentuated total-reflectance Fourier transform infrared (ATR-FTIR) and scanning X-ray photoelectron spectroscopy (S-XPS). Scanning electron microscopy (SEM) revealed a rough surface morphology and confinement of the PNIPAAm graft layer to the surface of the fibres in the gNWF. The OAGP method did not affect the crystalline phase of bulk PP, however, twin-melting thermal peaks were detected for the oNWF and gNWF indicating crystal defects. Contact angle studies showed that the surface of the gNWF exhibited a thermoresponsive behaviour. Hepatocyte cells attached onto gNWF disks in a bioreactor at 37 °C and remained viable for 10 days in culture. Upon cooling the cell culture media to 20 °C, cells were spontaneously released as 3D multi-cellular constructs without requiring destructive enzymes. The development of 3D thermoresponsive scaffolds capable of non-invasive 3D cell culture could provide a more reliable in vitro model for cells.

Cellulose nanofibres (CNF) with diameter 10–60 nm were isolated from raw banana fibres by steam explosion process. These CNF were used as reinforcing elements in natural rubber (NR) latex along with cross linking agents to prepare nanocomposite films. The effect of CNF loading on the mechanical and dynamic mechanical (DMA) properties of NR/CNF nanocomposite was studied. The morphological, crystallographic and spectroscopic changes were also analyzed. Significant improvement of Young’s modulus and tensile strength was observed as a result of addition of CNF to the rubber matrix especially at higher CNF loading. DMA showed a change in the storage modulus of the rubber matrix upon addition of CNF which proves the reinforcing effect of CNF in the NR latex. A mechanism is suggested for the introduction of the Zn–cellulose complex and its three dimensional network as a result of the reaction between the cellulose and the Zinc metal which is originated during the composite formation.

Polylactide (PLA)/starch blend/clay and PLA/clay composites are prepared by melt blending. Structural and thermal characterizations are performed by differential scanning calorimetry, X-ray diffraction analysis, and thermogravimetric analysis. The fire properties are assessed on a dual cone calorimeter. Combustion residue and char formation is characterized by optical microscopy and attenuated total reflection infrared spectroscopy. Although the clay is not fully intercalated/exfoliated, the composites exhibit a higher thermal stability and much reduced peak heat release rate, and the PLA/starch blend composite retains its mechanical properties. For the PLA/starch blend composite, smoke release is also considerably reduced. Catalyzed, oxidative decomposition is shown to occur early in the thermal decomposition of the composites, prior to increased thermal stability. The inclusion of clay promotes char formation and increases the quantity of carbonaceous char in the combustion residue. There is minimal migration of the clay to the surface prior to ignition and char is formed mainly after ignition and during burning. During the later stages of burning some of the char formed is converted to CO2.

Bio-composites (FF-PFA-D) were successfully compression moulded by reinforcing polyfurfuryl alcohol (PFA) with 10 layers of woven flax fabric (FF). FF-reinforced PFA-based bio-composites were then immersed in water to get wet bio-composite samples (FF-PFA-W). Mechanical and impact properties of the bio-composites in dry and wet state were determined. Characterisations of the bio-composites were performed by thermogravimetric analysis, thermomechanical behaviour, and cone calorimeter data. Results indicated the increase in α-relaxation temperature for FF-PFA-W. SEM micrograph showed that the flax fibres were completely coated with the resin indicating complete wetting of the fabrics by the matrix. As expected, time of ignition showed an increase for the bio-composites due to the flame retardant characteristics of PFA. This work gives us simple and effective way to prepare bio-composites from 100 % renewable resources.

Copyright: 2012 Wiley. This is the pre print version of the work. The definitive version is published in the Journal of Applied Polymer Science, vol. 127(1), pp 274-281

More than 200 insect pests are found growing on pigeonpea. Insects lay eggs, attack and feed on leaves, flowers and developing pods. Plants have developed elaborate defenses against these insect pests. The present work evaluates protease inhibitor (PI) based defense of pigeonpea in leaves and flowers. PIs in the extracts of these tender tissues were detected by using gel X-ray film contact print method. Up to three PIs (PI-3, PI-4 and PI-5) were detected in these tissues as against nine (PI-1–PI-9) in mature seeds. PI-3 is the major component of these tissues. Mechanical wounding, insect chewing, fungal pathogenesis and application of salicylic acid induced PIs in pigeonpea in these tissues. Induction was found to be local as well as systemic but local response was stronger than systemic response. During both local and systemic induction, PI-3 appeared first. In spite of the presence and induction of PIs in these tender tissues and seeds farmers continue to suffer yield loses. This is due to the weak expression of PIs. However the ability of the plant to respond to external stimuli by producing defense proteins does not seem to be compromised. This study therefore indicates that PIs are components of both constitutive and inducible defense and provide a ground for designing stronger inducible defense (PIs or other insect toxin based) in pigeonpea.

The study on heat transport in composites is of fundamental importance in engineering design and for tailoring thermal and mechanical behaviour of materials. In this study, the thermal conductivity and thermal diffusivity of flax reinforced polypropylene (PP) composites were determined at room temperature. Chemical modification in the form of a biodegradable zein coating was applied to the flax nonwovens. The effect of fibre loading and chemical modification on the thermo-physical properties was investigated. Dielectric permittivity studies were also evaluated and the dielectric constant of fibre reinforced composites was found to be higher than that of PP. The heat flow and crystallinity effects of the composites were also determined by differential scanning calorimetric (DSC) studies. Zein modification of the flax fibres resulted in a decrease of thermal conductivity and diffusivity which was attributed to a decrease in velocity and mean free path of phonons due to increase in interfacial adhesion.

Biocomposites were successfully prepared by the reinforcement of soy protein isolate (SPI) with different weight fractions of woven flax fabric. The flax-fabric-reinforced SPI-based composites were then arylated with 2,2-diphenyl-2-hydroxyethanoic acid (DPHEAc) for 4 h to obtain arylated biocomposites. A new method was proposed to determine the amount of carbon dioxide evolved during the arylation of the soy protein in the presence of DPHEAc. Characterizations of the arylated and nonarylated biocomposites were done by Fourier transform infrared spectroscopy, thermogravimetric analysis, and dynamic mechanical thermal analysis. The results indicate that the arylated soy-protein-based composites exhibited mechanical behavior like brittle-matrix composites, which differentiated them from nonarylated soy-protein-based composites, which showed mechanical behavior similar to polymer–matrix composites. In the arylated composites, there was clear evidence of a stick–slip mechanism, which perhaps dominated and, therefore, prevented easy deformation of the reinforced film. Scanning electron microscopy studies revealed cracks in the arylated soy protein composites when they were subjected to tensile tests. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Surface oxyfluorination had been carried out on polypropylene non-woven fabric (PP NWF) samples of different morphologies and pore sizes. The modified surfaces were characterised by Attenuated Total Reflectance Fourier Transform InfraRed (ATR-FTIR)-spectroscopy, FTIR imaging microscopy, X-Ray Photoelectron Spectroscopy (XPS), Electron Spin Resonance (ESR) spectroscopy, Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD) analysis, Scanning Electron Microscopy (SEM), dynamic rheometry and Thermo-Gravimetry (TG). ATR-FTIR and XPS techniques revealed the presence of –CF, –CF2, –CHF and –C(O)F groups. The formed –C(O)F groups mostly got hydrolysed to –COOH groups. The C=O groups of alpha-haloester, and the C=C stretching of the formed –CF=C(OH)– groups could also be detected. Long-lived radicals could be detected on the functionalised surfaces as middle-chain peroxy radicals by ESR spectroscopy. SEM micrographs showed slight roughening of the oxyfluorinated surfaces. Oxyfluorination had no significant effect on the crystalline structure and phase composition of the PP NWF samples supported by DSC and XRD measurements. The molecular mass of the samples were unaffected by the oxyfluorination treatment as proved by oscillating rheometry. The surface modification, however, significantly affected the thermal decomposition but not affected the thermo-oxidative decomposition of PP NWFs. Different morphologies and pore sizes of PP NWF samples resulted in reproducibility of the findings, although did not substantially affect surface functionalisation.

The objective of this work was to develop a simple process to obtain an aqueous stable colloid suspension of cellulose nano fibrils from various lignocellulosic fibres. For the preliminary analysis we have studied three different fibres: banana (pseudo stem), jute (stem) and pineapple leaf fibre (PALF). To study the feasibility of extracting cellulose from these raw fibres we have adopted steam explosion technique along with mild chemical treatment. These processes included usual chemical procedures such as alkaline extraction, bleaching, and acid hydrolysis but with a very mild concentration of the chemicals. The chemical constituents of the fibre in each processing step were determined by ASTM standard procedures. Morphological, spectroscopic and thermal analyses of the fibres were carried out and found that the isolation of cellulose nanofibres occurs in the final step of the processing stage and they possess improved thermal stability for various advanced nanotechnological applications.

Copyright: 2011 Bentham Science Publishers. This is the pre print version of the work. The definitive version is published in Current Nanoscience, Vol. 7(3), pp. 396-401

The different elements are essentials for growth and fertilization of plants. Such as carbon, nitrogen, phosphorous, potash and some other materials are essential for plants in proper proportion. The qualities of soil are different at different area and it also fit for different crops. We analyzed thousands of soil samples by using various chemical and instrumental methods for Daskroi-taluka of Ahmedabad District, like pH metry, conductometry, colorimetric. Here action of soil measured by pH, amount of soluble salt measured by Electric conductivity, organic carbon and phosphorous measured by colorimetric and potash measured by flame photometer. These results also compare with the standard elemental data available for particular crops. Finally we explore excess or deficiency of carbon, nitrogen, phosphorous, potash and some other materials in the soil and discussed some important results for the land of Daskroi-taluka of Ahmedabad district.

This article reports a study on the effect of different natural fibres, their blend ratios and varying air gaps between a needle-punched non-woven fabric and polystyrene backing on the sound absorption coefficients of the needle-punched non-woven fabrics. These parameters as well as their interactive effects were studied by variance analysis. The air gap varied from 0 to 25 mm in 5 mm increments; three natural fibre types (agave, flax and waste wool) were used; each one blended with polyester fibres in three blending ratios. The univariate test of significance showed that all three parameters and two of the three two-way interactions effects on sound absorption coefficients were significant. Only two-way interaction effect between blend ratio and air gap on sound absorption coefficient was not significant. It was found that the sound absorption coefficients increased with an increase in air gap size up to 15 mm, after which they decreased slightly as the air gap was increased further to 25 mm. In addition, the non-woven fabrics produced from the blend of waste wool and polyester fibres achieved the highest sound absorption coefficients than those of the other two natural fibres, and generally, the sound absorption coefficients increased with the increase in polyester fibre content in each blend studied.

Biocomposites were successfully prepared by reinforcing polylactic acid with flax fibres (PF). To improve the interfacial adhesion between the matrix and the fibres, amphiphilic compounds as additives were introduced. Structural and thermal characterisations of the PF were performed by Fourier transform infrared spectra, differential scanning calorimetry and thermogravimetric analysis. The interfacial adhesion between the fibres and the matrix was visually assessed from the SEM images of fractured specimens. Dynamic mechanicalthermal analysis was performed to evaluate the damping behaviour of the composites and thereby to interpret the interfacial adhesion between fibres and the matrix. It was observed that in the case of mandelic acid, particles/spheres were generated, resulting in effective stress transfer from the matrix resins to flax fibres, thereby increasing the storage modulus and impact strength of the composites. Mechanical properties and the water uptake of the composites with amphiphil...

Bio-composites (PF) were successfully prepared by reinforcing poly lactic acid (PLA) with woven flax fibers (F) in the presence of mandelic acid, benzilic acid, dicumyl peroxide (DCP) and zein as additives. To improve the mechanical properties of the bio-composites, montmorillonite clay (MMT) was also added. Characterizations of the bio-composites in presence and absence of MMT were performed by FTIR, DSC, TGA and DMTA. The interfacial adhesion between the fibers and the matrix was qualitatively assessed from SEM micrographs of fractured specimens. Intercalation of MMT with 1.4 nm basal spacing was observed in the PLA matrix leading to the increased modulus and water resistance of the bio-composites. Results indicated that mandelic acid and dicumyl peroxide acted as efficient additives for this system. This work provided us the exploratory idea of using MMT in presence of amphiphilic compounds as additives in bio-composites for possible applications.

Kinetics of autothermal reforming (ATR) of tetradecane on Pt–Al2O3 catalyst over the temperature range 750–900 °C is investigated. Experimental results obtained from NETL (US-DOE) are used for model parameter estimation and validation. Two Langmuir–Hinshelwood–Hougen–Watson (LHHW) type rate models are developed and subjected to parameter estimation and model discrimination. LHHW model in which hydrocarbon is adsorbed on the catalyst surface as alkyl intermediate species by scission of C–H bond gave physically meaningful parameters. Parameters are estimated by using generalized reduced gradient method in spreadsheet and sequential quadratic programming in Matlab. The estimated parameters for the selected model are thermodynamically consistent. The developed kinetic model could capture the experimental behavior of the process and could predict the outlet composition within 25% error.

Electrospinning is a simple method of producing nanofibers by introducing electric field into the polymer solutions. We report an experimental investigation on the influence of processing parameters and solution properties on the structural morphology and average fiber diameter of electrospun poly ethylene oxide (PEO) polymer solution. Experimental trials have been conducted to investigate the effect of solution parameters, such as concentration, molecular weight, addition of polyelectrolyte in PEO solution, solvent effect, as well as governing parameter, such as applied voltage. The concentration of the aqueous PEO solution has shown noteworthy influence on the fiber diameter and structural morphology of electrospun nanofibers. At lower concentrations of PEO polymer solution, the fibers showed irregular morphology with large variations in fiber diameter, whereas at higher concentrations, the nanofibers with regular morphology and on average uniform fiber diameter were obtained. We find that the addition of polyelectrolytes, such as sodium salt of Poly acrylic acid (PAA) and Poly allylamine hydrochloride (PAH), increases the conductivity of PEO solutions and thereby decreases the bead formation in electrospun nanofibers. The increase in applied voltage has been found to affect the structural morphology of nanofiber while the addition of ethanol in PEO solution diminishes the bead defects. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Woven and nonwoven flax fiber reinforced poly lactic acid (PLA) biocomposites were prepared with amphiphilic additives as accelerator for biodegradation. The prepared composites were buried in farmland soil for biodegradability studies. Loss in weight of the biodegraded composite samples was determined at different time intervals. The surface morphology of the biodegraded composites was studied with scanning electron microscope (SEM). Results indicated that in presence of mandelic acid, the composites showed accelerated biodegradation with 20-25% loss in weight after 50-60 days. On the other hand, in presence of dicumyl peroxide (as additive), biodegradation of the composites was relatively slow as confirmed by only 5-10% loss in weight even after 80-90 days. This was further confirmed by surface morphology of the biodegraded composites. We have attempted to show that depending on the end uses, we can add differ- ent amphiphilic additives for delayed or accelerated biodegradability. This work gives us the idea of biodegradation of materials from natural fiber reinforced PLA composites when discarded carelessly in the environment instead of proper waste disposal site.

This paper presents thermodynamic analysis of commercial diesel with 50 ppm sulfur content for the three common modes of reforming operations. Thermodynamic analysis is done to get boundary data for carbon formation and to get the composition of various species for all modes and entire range of operations. For steam reforming operation, steam-to-carbon (S/C) ratio equal to or greater than 2 is required for carbon-free operation in entire temperature range (400–800 °C). However, selection of S/C ratio requires the balance between maximizing the hydrogen yield and minimizing the energy input both of which increase with increasing S/C ratio. For partial oxidation operation, O 2 /C ratio of 0.75 is preferable to maximize hydrogen yield but carbon formation can occur if regions of reactor experience temperatures lower than 700 °C. In case of autothermal reforming, for carbon-free operation, temperature of 750 °C, O 2 /C ratio in the range of 0.125–0.25 and S/C ratio greater than 1.25 and ideally 1.75 is recommended. However, enthalpy analysis indicates that it is not possible to reach to thermoneutral point at this condition so it is better to operate O 2 /C ratio 0.25 or little higher with constant heat supply. A set of three independent reactions is proposed that along with element balance equations can adequately describe the equilibrium composition of six major species—H 2 , CO 2 , CO, H 2 O, CH 4 , and C for the entire range of reforming operation.

Natural fibre is often used as reinforcement in polymer composites. The main problem of using these natural fibres is their poor compatibility and hydrophilic nature. Therefore, chemical modification of constituents becomes necessary to enhance adhesion between hydrophilic fibre and hydrophobic polymer matrix. The aim of this work is to improve the interfacial adhesion between the polypropylene matrix and the nonwoven flax batting. Chemical treatments with acrylic acid, 4-pentanoic acid, 2,4-pentadienoic acid, and 2-methyl-4-pentanoic acid were investigated. The composites were processed by compression molding using a film stack method. The mechanical properties of these modified composites, such as tensile, flexural, and impact strength were analyzed and compared. It was found that these properties were dependent on the kind and amount of chemical treatment. SEM and thermal studies were also conducted.

Nonwoven mats from hemp and polypropylene fibers in various proportions are produced and hot pressed to make composite material. The effect of hemp fiber content and anisotropy in the nonwoven mats resulting from the carding technology are examined on the basis of the three-point bending, tensile, and impact properties of the resultant composite materials. Because of the hydrophilic nature and poor dimensional stability of cellulosic fibers due to swelling, the effect of water sorption on mechanical performances is also investigated. Optimal mechanical properties are achieved in composites made from 40 to 50% of hemp fiber by weight. As expected, better mechanical properties are found in the specimens cut from the composite sheets parallel to the direction of carding. A strong decrease in three-point bending properties is noticed after immersing the composite samples in distilled water for 19 days, while the impact strength increased. Double carding of raw materials results in a decreased anisotropy in the composite material.

This article presents the results from a study on the cross-plane water flow through the needle punched nonwoven geotextiles produced from polypropylene fibers. Different types of nonwoven geotextiles are produced by varying the processing parameters during the needle punching process. The pore characteristics and the cross- plane water flow (or permeability) through the nonwoven geotextiles are measured by liquid extrusion porometry and water permeability tester, respectively. The water flow velocities through the geotextiles are predicted by the finite element analysis. There is a good correlation between the average velocity data obtained from water permeability test and theoretical prediction based on finite element analysis. The pore characteristics play an important role in water permeability behavior of nonwoven geotextiles. 2008 Wiley Periodicals, Inc. J Appl Polym Sci 108: 3876-3880, 2008

Composite materials reinforced with natural fibres, such as flax, hemp, kenaf and jute, are gaining increasing importance in automotive, aerospace, packaging and other industrial applications due to their lighter weight, competitive specific strength and stiffness, improved energy recovery, carbon dioxide sequestration, ease and flexibility of manufacturing and environmental friendliness besides the benefit of the renewable resources of bast fibres. The market scenario for composite applications is changing due to the introduction of newer biodegradable polymers, such as PLA synthesized from corn, development of composite making techniques and new stringent environmental laws requiring improved recyclability or biodegradability for industrial applications where stress bearing capacities and micro-mechanical failures dictate serviceability. Bast fibre reinforced composites, made from biodegradable polymers, will have to compete with conventional composites in terms of their mechanical behaviour. B...

The high operating power density and aggressively scaled geometries associated with 400+ GHz InP-Based DHBTs present a new challenge in device design and thermal management. In order to assess the effects of self-heating on the RF performance, S -parameters of six InP DHBTs with varying emitter dimensions were measured over a 75 °C ambient temperature range. An 8–10% increase in peak f T is observed as the temperature is reduced. Data analysis indicates that reductions in the base and collector transit times and the base–emitter charging times are responsible for the peak f T improvement. The calculated electron velocities exceed 6 × 10 7 cm/s, indicating velocity overshoot plays a critical role in the reduction of the transit times. When emitter scaling are considered, the total transit time variation is directly correlated to the rise in junction temperature. Using previously measured thermal resistance values, a 77–116 °C minimum junction temperature rise is estimated from self-heating. Therefore, the 8–10% increase in peak f T is a reasonable estimate of the performance to be recovered by minimizing self-heating. Improved intra-device thermal management through device design is an important supplement to geometry scaling as a means to enhance device performance.

Recent attempts to achieve 400 GHz or higher fT and f MAX with InP heterojunction bipolar transistors (HBTs) have resulted in aggressive scaling into the deep submicrometer regime. In order to alleviate some of the traditional mesa scaling rules, several groups have explored selectively implanted buried subcollectors (SIBS) as a means to decouple the intrinsic and extrinsic collector design. This allows tauC to be minimized without incurring a large total CBC increase, and hence, a net improvement in fT and fMAX is achieved. This paper represents the first investigation into the series resistance and capacitance characteristics of submicrometer-width SIBS regions (as narrow as 350 nm) for InP double HBTs. Although the SIBS resistance is higher than that of epitaxially grown layers, the SIBS concept is able to provide good dopant activation and a significant decrease in CBC. S-parameter measurements are presented to clarify the impact of SIBS geometry variations, caused by both intentional device design and process variations, on fT and fMAX. Parasitic resistances and high background doping limit the fT improvement, but the CBC reduction is sufficient to demonstrate a 30% increase in fMAX. Results indicate that further improvements in fT and fMAX using the SIBS concept will be possible

Nonwoven mats from hemp and polypropylene fibres in various proportions were produced and hot pressed to make composite material. The effect of hemp fibre content and anisotropy in nonwoven mats resulting from the carding technology were examined on the basis of the three-point bending, tensile and impact properties of the resultant composite materials. Because of the hydrophilic nature and poor dimensional stability of cellulosic fibres due to swelling, the effect of water sorption on mechanical performances was also investigated. Optimal mechanical properties were achieved in composites made from 40-50% of hemp fibre by weight. As it was expected, better mechanical properties were found in the specimens cut from the composite sheets parallel to the direction of carding. A strong decrease in three point bending properties was noticed after immersing the composite samples in distilled water for 19 days, while the impact strength increased. Double carding of raw materials resulted in a decreased anisotropy in composite material.

We have demonstrated InP/InGaAs/InP MBE-grown DHBTs fabricated with patterned sub-collector by elevated temperature 200 °C N+ implant and subsequent device material over growth. F t / F max > 250 GHz/300 GHz were obtained on DHBTs with 0.35 μm × 6 μm emitters from this process. Ring oscillators fabricated with this process showed good uniformity with 82% of yield on wafers and an average gate delay of 8 ps. Difference of surface morphology on re-grown DHBT layers over elevated temperature implanted and room temperature 22 °C implanted sub-collector was observed.

We describe a quasi-planar HBT process using a patterned implanted subcollector with a regrown MBE device layer. Using this process, we have demonstrated discrete SHBT with f/sub t/>250 GHz and DHBT with f/sub t/>230 GHz. The process eliminates the need to trade base resistance for extrinsic base/collector capacitance. Base/collector capacitance was reduced by a factor of 2 over the standard mesa device with a full overlap between the heavily doped base and subcollector regions. The low proportion of extrinsic base/collector capacitance enables further vertical scaling of the collector even in deep submicrometer emitters, thus allowing for higher current density operation. Demonstration ring oscillators fabricated with this process had excellent uniformity and yield with gate delay as low as 7 ps and power dissipation of 6 mW/CML gate. At lower bias current, the power delay product was as low as 20 fJ. To our knowledge, this is the first demonstration of high-performance HBTs and integrated circuits using a patterned implant on InP.

lnP/GaAssSb/InP double heterojunction bipolar transistor structures were grown in a solid-source molecular beam epitaxy system. Carbon or Be was used for the p-type doping of GaAs 0.51 Sb 0.49v . Hole concentrations in excess 2x l0 20 cm 3 were obtained in carbon doped GaAs 0.51 Sb 0.49 films. lnP/GaAssb/lnP double heterojunction bipolar transistors were fabricated as wet-etched triple mesa structures. Common-emitter current gain, β> 80 was measured for large area devices with 20:- 20μm 2 emitter geometry, and a base doping of 1 x10 19 cm BV CEO >6V was measured for devices incorporating a 2000 A thick InP collector. The gain of the transistor decreased to 20 as the base doping level was increased to 5 x 10 1.9 cm 3 .

InAsSb material with a cutoff wavelength in the 5 μm range has been grown on GaAs substrates. The MWIR InAsSb detector arrays were fabricated and hybridized to a ROIC to permit measurement of the electrical and optical properties of detectors. Detector arrays were fabricated in a 1024 x 1024 format on an 18 μm pitch. A fanout was utilized to directly acquire data from a set of selected detectors without an intervening read out integrating circuit (ROIC). Variable temperature Jdark vs Vd measurements have been made with the dark current density ~ 10-5 A/cm 2 at 150 K. The external QE measured using a narrow band filter centered at ~ 4 μm had values in the 65 – 70 % range. Since the detectors were illuminated through a GaAs substrate, which has a reflectance of 29%, the internal QE is greater than 90%. A 1024 x 1024 ROIC on an 18 μm pitch was also designed and fabricated to interface with the barrier detectors. The ROIC operates at 30 Hz frame rate and has a well capacity of 20.7 M electrons. QE at 150 K for a 1024 x 1024 detector array hybridized to a ROIC had a median D* at 150 K under a flux of 1.07 x 1015 ph/(cm 2 /s) was 1.2 x 1011 cm Hz1/2 /W. The NEdT was 44 mK and imagery was obtained at 150 K using an f/2.3 MWIR lens.

InAsSb material with a cutoff wavelength in the 5 μm range has been grown on GaAs substrates. The MWIR InAsSb detector arrays were fabricated and hybridized to fanouts and ROICs to permit measurement of the electrical and optical properties of detectors. Detector arrays were fabricated in a 1024 x 1024 format on an 18 μm pitch. A fanout was utilized to directly acquire data from a set of selected detectors without an intervening read out integrating circuit (ROIC). Variable temperature Jdark vs Vd measurements have been made with the dark current density ~ 10 -5 A/cm 2 at 150 K. The external QE measured using a narrow band filter centered at ~ 4 μm had values in the 65 - 70 % range. Since the detectors were illuminated through a GaAs substrate which has a reflectance of 29%, the internal QE is greater than 90 %. A 1024 x 1024 ROIC on an 18 μm pitch was also designed and fabricated to interface with the barrier detectors. The ROIC operates at 30 Hz frame rate and has a well capacity of 20.7 M electrons. QE at 150 K for a 1024 x 1024 detector array hybridized to a ROIC had a median D* at 150 K under a flux of 1.07 x 10 15 ph/(cm 2 /s was 1.2 x 10 11 cm Hz 1/2 /W. The NEdT was 44 mK and imagery was obtained at 150 K using an f/2.3 MWIR lens.

Progress on achieving reproducible growth of high performance, dual-band IR detector structures in HgCdTe grown by molecular beam epitaxy (MBE) is described. The reproducibility achieved in the MBE growth of n-p-n device structures comprising HgCdTe epitaxial layers with different composition and doping characteristics was evaluated from the run-to-run precision in the alloy composition, dopant concentration and dislocation density. For a series of 25 growth runs, the standard deviation of the alloy composition in the n-type absorbing layer was 0.002; the yield for the in situ n- and p-type doping process was > 95%; and the average dislocation density was < 5 x 10 5 cm -2 . In situ optical diagnostics, including spectroscopic ellipsometry and an optical absorption flux monitor were used for the real-time determination of the alloy composition and Cd flux during MBE growth of the two-color device structures. Focal plane arrays with 128 x 128 elements were fabricated for the simultaneous detection of two sub-bands in the MWIR spectrum. Average R o A values exceeding 1 x 10 6 and 2 x 10 5 Ω cm 2 were measured at 77 K for diodes operating at 4.0 and 4.5 μm, respectively, and the quantum efficiency was greater than 70% in each band. These results on MBE growth and device performance demonstrate that HgCdTe MBE technology is poised for the modest-scale production of advanced IR devices.

We describe an integrated real-time sensing and control system for monitoring and controlling substrate temperature, layer composition, and effusion cell flux during molecular beam epitaxial growth of HgCdTe epilayers for advanced IR detectors. Substrate temperature is monitored in real-time using absorption-edge spectroscopy, allowing the temperature to be controlled within 1.5°C of the desired setpoint. In situ spectroscopic ellipsometry (SE) is used for monitoring HgCdTe layer composition in real-time. A comprehensive temperature- and composition-dependent dielectric function database has been recorded which allows the accurate and precise determination of Hg1−xCdxTe layer composition over a wide range of x-values, from 0.2 to 0.42. The composition changes inferred from real-time SE measurements obtained during growth of a two-layer structure are in excellent agreement with composition profiles obtained using post-growth secondary ion mass spectroscopy analysis. The accuracy and precision of SE measurements conducted over multiple growth runs are shown to be suitable for robust SE-based composition control. Changes in the Cd flux produced by a CdTe effusion cell are detected using an atomic optical absorption method. This method allows changes in HgCdTe layer composition to be correlated directly with variations in Cd flux. All of the in situ sensors are linked using a custom software framework to provide the foundation for real-time monitoring and control of HgCdTe MBE growth of high performance infrared detector structures over a wide range of compositions, layer thicknesses, and substrate temperatures.