Estimation of the Surface Tensions of Benzonitrile, Chlorobenzene, Benzyl Chloride and Benzyl Alcohol in Mixtures with Benzene by Associated and Non-associated Processes at 298.15, 303.15 and 313.15 K

Densities and surface tensions were measured for the binary liquid mixtures formed by benzonitrile, chlorobenzene, benzyl chloride and benzyl alcohol with benzene, at 298.15, 303.15 and 313.15 K and atmospheric pressure, over the whole composition range. The Prigogine?CFlory?CPatterson model (PFP), the Ramaswamy and Anbananthan (RS) model, the model derived by Glinski, the Sanchez equation, the Goldsack relation and Eberhart??s model were used to predict the associational behavior of weakly interacting liquids. The measured properties were fitted to the Redlich?CKister polynomial equation to estimate the binary coefficients and standard errors. Furthermore, the McAllister multi-body interaction model was also used to correlate the binary solution properties. These non-associated and associated models were compared and tested for different systems, showing that considering the association processes yields better agreement between theory and experiment as compared to non-associated processes.     

Heterologous Expression of Legumin Gene in <Emphasis Type="Italic">E. coli</Emphasis> Isolated from cDNA Clones of Immature Seeds of Pigeonpea (<Emphasis Type="Italic">Cajanus cajan</Emphasis> L.)

Proteins are one of the targets for improving the nutritional quality, and attempts are being made through manipulation of its native gene(s). Pigeonpea (Cajanus cajan L.) is one of the nutritionally important legumes of tropical and subtropical regions of the world, and studies of the structure of seed storage proteins and their interactions have been limited by the difficulty of isolating single-protein subunits in large amounts from a complex mixture of the seed endosperm. One way to overcome this problem is the expression of seed storage protein-encoded gene(s) in heterologous systems that have additional advantages wherein specific gene modifications can be made and the new gene constructs can quickly be expressed. Legumin protein was extracted from pigeonpea seeds of different developmental stages (5th to 25th day after flowering [DAF]) and characterized. The legumin gene (leg) of size 1.482 kb was screened, using the deoxygenin-labeled legumin probe, from the complementary deoxyribonucleic acid (cDNA) library, constructed from 18-day-old (DAF) immature seeds of pigeonpea and sequenced (accession no. AF3555403). The legumin gene was further characterized by DNA blotting, and its probable secondary structure was predicted using online ExPASy server. Significant Protein Data Bank (PDB) alignment of the deduced legumin protein by BLASTP was observed with proglycinin of soybean. Comparative 3D structural homology was predicted by Cn3D software, and the legumin protein showed the 3D structure alignment and interaction homology with proglycinin chain 1FXZA (PDB no. 1FXZ). The legumin gene was subcloned in vector pET-24a driven by the bacterial promoter, and its expression was detected in Escherichia coli by immunoblotting using polyclonal antibodies, raised against the purified legumin protein.     

Application of Response Surface Method for Studying the Role of Dissolved Oxygen and Agitation Speed on Gamma-Linolenic Acid Production

To study the effect of agitation speed (rpm) and dissolved oxygen concentration (DO) on the production of gamma linolenic acid by Mucor sp. RRL001, a central composite design experiment was performed in a 5-L stirred tank bioreactor. The design consisted of a total of 10 runs consisting of runs at five levels for each factor and was divided in two blocks. The ANOVA analysis and Pareto chart of effects suggested agitation speed (p = 0.0142) linear effect and DO concentration (p = 0.0342) quadratic effects were significant factors with significant contribution to the response. The validation run based on the optimum production zone in response surface plot resulted in the maximum 350.3 mg l⁻¹ GLA yield as compared with model predicted value of 340.7 mg l⁻¹. The study suggests that agitation rate is having more pronounced effect on GLA yield than dissolved oxygen concentration by ensuring enhanced mass transfer and by preventing wall growth at elevated agitation speed. Also, it shows that higher GLA yields can be obtained in a simple medium at moderate oxygen saturation and that the Mucor sp. RRL001 is resistant to high agitation linked shear stress and suitable for GLA production at higher scale.     

Nonlinear coupling of transverse modes of a fixed–fixed microbeam under direct and parametric excitation

Tuning of linear frequency and nonlinear frequency response of microelectromechanical systems is important in order to obtain high operating bandwidth. Linear frequency tuning can be achieved through various mechanisms such as heating and softening due to DC voltage. Nonlinear frequency response is influenced by nonlinear stiffness, quality factor and forcing. In this paper, we present the influence of nonlinear coupling in tuning the nonlinear frequency response of two transverse modes of a fixed–fixed microbeam under the influence of direct and parametric forces near and below the coupling regions. To do the analysis, we use nonlinear equation governing the motion along in-plane and out-of-plane directions. For a given DC and AC forcing, we obtain static and dynamic equations using the Galerkin’s method based on first-mode approximation under the two different resonant conditions. First, we consider one-to-one internal resonance condition in which the linear frequencies of two transverse modes show coupling. Second, we consider the case in which the linear frequencies of two transverse modes are uncoupled. To obtain the nonlinear frequency response under both the conditions, we solve the dynamic equation with the method of multiple scale (MMS). After validating the results obtained using MMS with the numerical simulation of modal equation, we discuss the influence of linear and nonlinear coupling on the frequency response of the in-plane and out-of-plane motion of fixed–fixed beam. We also analyzed the influence of quality factor on the frequency response of the beams near the coupling region. We found that the nonlinear response shows single curve near the coupling region with wider width for low value of quality factor, and it shows two different curves when the quality factor is high. Consequently, we can effectively tune the quality factor and forcing to obtain different types of coupled response of two modes of a fixed–fixed microbeam.

     

Sol-gel synthesis and characterization of adsorbent and photoluminescent nanocomposites of starch and silica

Using sol-gel method, mesoporous and photoluminescent silica nanocomposites of soluble starch have been synthesized and characterized. Different ratios of H₂O, TEOS and EtOH were used at fixed template (soluble starch) and catalyst (NH₄OH) concentrations to obtain materials of different performances in terms of heavy metal binding from a solution which has been monitored using Cd(II) as representative divalent heavy metal ion. Optimum material was obtained when H₂O, TEOS and EtOH were used in 14:1:2 ratio. This sample was not only an efficient metal ion adsorbent but also had an intense luminescence in ultra-violet region and potentially may be used in silicon-based UV-emitting devices. Metal binding by the material was further enhanced after calcination (at 800 °C in air) while its luminescence had a multipeak profile in UV-visible region. In a batch adsorption study, calcined hybrid composite (0.25 g/L) could remove 98.5% Cd(II) from 100 mg/L Cd(II) solution in 2 h. The chemical, structural and textural characteristics of the synthesized materials have been investigated using Fourier Transform Infrared Spectroscopy (FTIR), X-rays Diffraction (XRD), Thermal Analysis (TGA/DTA), Photoluminescence (PL), Brunauer-Emmett-Teller Analysis (BET) and Scanning Electron Microscopy (SEM).     

Ultrasonic wave propagation in rare-earth monochalcogenides

The ultrasonic attenuation in thulium monochalcogenides TmX (X=S, Se and Te) has been studied theoretically with a modified Mason’s approach in the temperature and range 100 K to 300 K along 〈100〉, 〈110〉 〈111〉 crystallographic directions. The thulium monochalcogenides have attracted a lot of interest due to their complex physical and chemical characteristics. TmS, TmSe and TmTe are trivalent metal, mixed valence state, and divalent semiconductor, respectively. Coulomb and Born-Mayer potential is applied to evaluate the second- and third-order elastic constants. These elastic constants are used to compute ultrasonic parameters such as ultrasonic velocities, thermal relaxation time, and acoustic coupling constants that, in turn, are used to evaluate ultrasonic attenuation. A comparison of calculated ultrasonic parameters with available theoretical/experimental physical parameters gives information about classification of these materials.      

Ion- Beam Modification of Peo Based Polymer Electrolytes

In this paper, we report the ion beam interaction with a well explored ion conducting polymer electrolyte, viz., polyethylene oxide complexed with sodium iodide (PEO:NaI). Li³⁺ ions at 50 MeV were bombarded on the film at different flux. The conductivity modulation of the films has been reported due to interaction at different fluence. The increase in the total conductivity is explained in terms of the change in the number of charge carriers and the dielectric constant of the polymer electrolyte films.     

Evolution of subsequent yield surfaces and elastic constants with finite plastic deformation. Part II: A very high work hardening aluminum alloy (annealed 1100 Al)

Results are presented on the evolution of subsequent yield surfaces with finite deformation in a very high work hardening annealed 1100 aluminum alloy. In Part I [Khan, A.S., Kazmi, R., Stoughton, T., Pandey, A., 2009a. Evolution of subsequent yield surfaces and elastic constants with finite plastic deformation. Part 1: a very low work hardening aluminum alloy (Al-6061–T6511) 25, 1611–1625.] of this paper, similar results are presented for a very low work hardening aluminum alloy. Those results were very different from the present ones, and all the results were for proportional loading paths. The subsequent yield surfaces are determined in tension, free end torsion and combined tension–torsion proportional and non-proportional loading paths, using 10 με deviation from linearity definition of yield. Yield surfaces are also determined after linear, bi-linear, and non-linear unloading paths after finite deformation under tension, free end torsion, and combined tension–torsion loading. The initial yield surface is closer to the von-Mises surface and the subsequent yield surfaces show distortion, expansion, positive cross-effect, and “nose” in the loading direction. Additionally, the subsequent yield surfaces after non-proportional loading paths show shrinkage and compounded distortion. The yield surfaces after unloading depict strong anisotropy, positive cross-effect and exhibits different proportion of distortion in each loading conditions. The Young’s and shear modulus decrease with plastic deformation and this decrease is much less than those reported in the published literature.     

Development of mica-based porous polymeric membrane and their application

To develop porous polymeric membrane, we have used poly(vinylidene-co-hexafluoropropylene) (P(VdF-HFP)) as a host matrix and the ionic liquid 1-ethyl-3-methylimidazolium tosylate as salt for the source of charge carriers in the polymer electrolyte system. Appropriate weight of mica (muscovite) has been added to the highest conducting polymer–salt electrolyte. The composite membrane has been prepared by breath figure method through controlling evaporation time and then tested this membrane for water filtration. The composite polymeric membrane has been characterized by X-ray diffraction, FTIR spectrometry, SEM, and electrochemical impedance spectroscopy. The pore volume in the mica-based film has been calculated, and it is found to be 64.3 % in the filler-dispersed membrane.