Modelling and kinetic aspects of a BTEX contaminated air-treating biofilter

In this study, the overall performance of a biofilter was evaluated in terms of its elimination capacity by using 3-D mesh techniques. The overall results indicate that the agreement between experimental data and model predictions is excellent for benzene, toluene, ethylbenzene and o-xylene (BTEX). In this study, the maximum removal rate (r _max) values for BTEX were 0.0117, 0.0126, 0.0081 and 0.0146 g m^–3 h^–1, and the half-saturation constant (K_S ) values were calculated to be 0.269, 0.297, 0.156 and 0.394 g m^–3, respectively. For this system, the coefficients of determination (r ²) of BTEX compounds were greater than 0.97. The BTEX concentration profiles along the depth were also determined using a convection–diffusion reactor (CDR) model. The sums of squares of the errors (SSEs) of BTEX were 0.0078, 0.0059, 0.0129 and 0.0269, respectively, with r ² values greater than 0.99 for all four compounds at low concentrations.     

Electrical behavior of dual‐morphology polyaniline

An attempt was taken to synthesize two types of polyaniline (PANI) with and without solvent followed by drying in air and vacuum oven conditions resulting different morphologies. The PANIs were prepared by chemical oxidative polymerization and studied with respect to their morphological features. Scanning electron microscopy, thermogravimetric analysis, X‐ray diffractometry, Fourier transform infrared spectroscopy, and ultraviolet–visible spectroscopy techniques were used for the characterization studies. The PANI synthesized with a solvent had a mixed morphology (fibrillar and granular), whereas PANI synthesized without a solvent had only a granular morphology. The direct‐current electrical conductivities of the samples were evaluated with an electrometer. We observed that the PANIs with mixed morphology (with solvent) were more electrically conducting than those with a single morphology (without solvent). On drying in vacuo, the conductivity of PANI decreased from 3.3 × 10^?2 to 0.3 × 10^?2 S/cm with solvent treatment, whereas it decreased from 0.1 × 10^?2 to 0.3 × 10^?3 S/cm without solvent treatment. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44091.     

Impact of Functionalized Polystyrenes as the Electron Injection Layer on Gold and Aluminum Surfaces: A Combined Theoretical and Experimental Study

At metal/organic interfaces, the insertion of an organic monolayer can significantly modify the surface properties of the substrate, especially in terms of charge injection across the interface. Herein, we study the formation of an insulating monolayer of morpholine or amine-functionalized polystyrene on Al(111) and Au(111) surfaces and its impact on surface work-function and charge injection. First-principles calculations based on Density Functional Theory have been carried out and point to a significant decrease in the work-function of modified metal surfaces; this is in very good agreement with ultraviolet photoemission spectroscopy measurements performed on the Au(111) surface. In addition, a bilayer cathode, consisting of a thin film of high-work-function metal, such as Al and Au, and a layer of amine-functionalized polystyrene, was also fabricated and tested in organic light-emitting diodes. Such bilayer structures exhibit substantially enhanced efficiency when compared with controls without the functionalized polymers. Our combined theoretical and experimental investigation gives insight into how a thin layer of a commodity polymer can be used to transform rather high-work-function metals into high-performance cathodes to provide efficient electron injection.     

pH‐sensitive crosslinked guar gum‐based superabsorbent hydrogels: Swelling response in simulated environments and water retention behavior in plant growth media

Crosslinked guar gum‐g‐polyacrylate (cl‐GG‐g‐PA) superabsorbent hydrogels were prepared to explore their potential as soil conditioners and carriers. The hydrogels were prepared by in situ grafting polymerization and crosslinking of acrylamide onto a natural GG followed by hydrolysis. Microwave‐initiated synthesis under the chosen experimental conditions did not exhibit any significant improvement over the conventional technique. The optimization studies of various synthesis parameters, namely, monomer concentration, crosslinker concentration, initiator concentration, quantity of water per unit reaction mass, particle size of backbone, and concentration of alkali were performed. The hydrogels were characterized by wide‐angle X‐ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and solid‐state ¹³C‐NMR spectroscopy. Swelling behavior of a candidate hydrogel [GG‐superabsorbent polymer (SAP)] in response to external stimuli, namely, salt solutions, fertilizer solutions, temperature, and pH, was studied. The GG‐SAP exhibited significant swelling in various environments. The effect of GG‐SAP on water absorption and the retention characteristics of sandy loam soil and soil‐less medium were also studied as a function of temperature and moisture tensions. The addition of GG‐SAP significantly improved the moisture characteristics of plant growth media (both soil and soil‐less), showing that it has tremendous potential for diverse applications in moisture stress agriculture. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41060.     

Nanostructured poly(3-hexylthiophene-2,5-diyl) films with tunable dimensions through self-assembly with polystyrene

Poly(3-hexylthiophene-2,5-diyl) is among the most widely used conjugated polymers for opto-electronic applications. To enhance its properties, researchers have attempted to nanostructure this polymer using various processes including breath figure arrays, nanolithography and elaborated organic synthesis. We here demonstrate a simple process to nanostructure the conjugated polymer using self-assembly with polystyrene and selective removal of one of the phases. The influence of the molecular weight of each polymer on the thin film morphology was systematically studied by atomic force microscopy. Using this approach, we observe two types of nanostructure, namely, nanoporous and nanoisland structures, of which the dimensions can be tuned by modifying the molecular weight of each polymer in the blend. This simple process introduces a cost-effective alternative to produce thin films of conjugated polymer with average nano-features from 100 nm up to 500 nm which could be used in a wide range of applications.     

A simple technique for grafting poly(methyl methacrylate) onto glass fabric

We have developed a two-step technique for synthesizing dichlorosuccinyl peroxide at room temperature, starting from succinic anhydride. It reacts with silanated glass fabric or beads at room temperature. The macroinitiator thus formed can be used for the polymerization of methyl methacrylate, MMA. We show that the MMA is grafted to the surface of glass giving a chemically bonded ultrathin coating, as confirmed by the FTIR analysis and electron micrography.     

Surface runoff estimation over heterogeneous foothills of Aravalli mountain using medium resolution remote sensing rainfall data with soil conservation system‐curve number method: A case of semi‐arid ungauged Manesar Nala watershed

Manesar Nala watershed, having an aerial extent of 71.53 km², was subjected to modelling of its hydrological behaviour for assessing its water resource potential. Modern tools and techniques of Remote Sensing (RS) and Geographic Information System (GIS) were used for assessment of runoff generating potential using the Hydrologic Soil Cover Complex (HSCC) Method [U.S. Department of Agriculture (USDA)‐Soil Conservation System‐Curve Number (SCS‐CN) approach]. RS and GIS were used in generation and integration of thematic maps [such as Land use/Land cover (using LISS‐III data) and Hydrologic Soil Group (HSG), (using soil map of study area) to derive the Curve Number (CN) for simulating Runoff (R_o)]. The daily rainfall (P) data for the study period 2002–2015 were acquired from NOAA Climate Prediction Center (NCPC). Corresponding R_o from the watershed for intense storm events for 14 years were calculated through RS and GIS. GIS and SCS‐CN model was employed for modelling the runoff production to study its hydrological behaviour. The study showed that the Manesar Nala watershed was having a composite Curve Number – II (CN_II) value of 82.5 for normal conditions. For dry and wet conditions these values were estimated at 66.44 (CN_I) and 91.56 (CN_III), respectively. This investigation showed that Manesar Nala watershed exhibited an annual average (of 14 years, 2002–2015) R_o volume of 4 542 514.37 m³ based on the average annual rainfall (P) of 0.72 m (720 mm). The average annual surface runoff (R_o) was predicted to be approximately 0.21 m with annual runoff coefficient (C_R) of 0.29. During the study, we also found a strong correlation ‘r’ between satellite driven P and R_o from NRCS‐CN method of the order of 0.94. The methodology so developed has the potential to be used in other similar ungauged watersheds in the same agro‐climatic conditions for the purpose of planning of watershed conservation measures and other developmental activities.     

Fabrication, Microstructural Characterization, and Mechanical Properties of Polycrystalline t'-Zirconia

Large-grained (100- to 200-μm), yttria-doped, polycrystalline t '-zirconia ceramics were fabricated by heat-treating presintered samples at temperatures 2100°C. Polarized light microscopy revealed the ferroelastic domain structure in the t ' samples. XRD showed that no monoclinic phase was detected on as-polished, ground and fracture surfaces, or on surfaces while under a tensile stress as high as 400 MPa. By contrast, relative changes occurred in the tetragonal peak intensities, which were attributed to ferroelasatic domain switching. The higher toughness of 3-mol%-Y₂O₃-doped t ' samples (7.7 MPa · m^1/2) compared to that of 8 mol% Y₂O₃ cubic samples (2.4 MPa · m^1/2) was explained in part by ferroelastic domain switching.     

Underground coal gasification: A new clean coal utilization technique for India

Energy demand of India is continuously increasing. Coal is the major fossil fuel in India and continues to play a pivotal role in the energy sector. India has relatively large reserves of coal (253 billion tonnes) compared to crude oil (728 million tonnes) and natural gas (686 billion cubic meters). Coal meets about 60% of the commercial energy needs and about 70% of the electricity produced in India comes from coal, and therefore there is a need for technologies for utilization of coals efficiently and cleanly. UCG offers many advantages over the conventional mining and gasification process. UCG is a well proven technology. Due to the site-specific nature of the process, possibility of land subsidence and surrounding aquifer water contamination, this technology is still in a developing stage in India. Potential for UCG in India is studied by comparing the properties of Indian coals with the properties of coal that are utilized by various UCG trials. The essential issues are elaborated for starting UCG in India based on the reported information from the successful field trials conducted all over the world. Indian industries are in the process of initiating pilot studies of UCG at various sites. This study will help to motivate both applied and theoretical research work on UCG sites in India and after detailed analysis it will provide basic data to interested industries.     

Recent advances in coherent anti-Stokes Raman scattering spectroscopy: Fundamental developments and applications in reacting flows

Coherent anti-Stokes Raman scattering (CARS) spectroscopy is widely used for measuring temperature and species concentration in reacting flows. This paper reviews the advances made over the last twelve years in the development and application of CARS spectroscopy in gas-phase reacting flows. The advent of high-power nanosecond (ns) lasers and off-the-shelf compact picosecond (ps) and femtosecond (fs) lasers is enabling the rapid expansion of the application of single-shot or high-bandwidth CARS spectroscopy in a way that would have been quite unimaginable two decades ago. Furthermore, compact ps lasers are paving the way for the development of a fiber-based CARS system for use in harsh environments. The objective of this paper is to provide an overview of recent progresses in ns-, ps-, and fs-CARS spectroscopy for gas-phase thermometry and species-concentration measurements since the second edition of A.C. Eckbreth's book entitled Laser Diagnostics for Combustion Temperature and Species, which was published in 1996. During the last two decades, four encompassing issues have driven the fundamental development and application of CARS spectroscopy in reacting flows: 1) measurement of temperature and concentration of multiple species with one CARS system, 2) extension of the application of traditional ns-CARS to challenging reacting flow environments, 3) performance of nonresonant background-free and collision-free measurements in high-pressure reacting flows, and 4) measurement of temperature and species concentration at high bandwidth, typically 1 kHz or greater, to address the instability and transient phenomena associated with turbulent reacting flows in the combustors and augmentors of modern propulsion systems. This review is focused on identifying and discussing the recent results of gas-phase CARS spectroscopy related to the four issues mentioned above. The feasibility of performing high-bandwidth CARS spectroscopy with one laser beam as well as the potential of tailored fs lasers for thermometry and species-concentration measurements in gas-phase reacting flows are also discussed.