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The homologous series of 4-cyano-4'-phenyl-phenol-alkanoates (nCOOCB) was studied under the influence of terahertz (THz) frequency range. The nCOOCB series has a re-entrant nematic phase, which is suitable for electro-optical properties under the THz frequency. The birefringence and order parameter expresses the twisting of the nematic phase at the higher frequency range. The director angle has fluctuated at a higher frequency range. The refractive index has remained constant at a higher frequency. The ionisation potential, electron affinity and Homo-Lumo energy gap continuously decrease with an extension of alkyl chain length; however, the dipole moment increases. The Homo-Lumo energy bandgap is reciprocal to the dipole moment.

In this work, different parameters of E7 liquid crystal (LC) have been calculated under the influence of an electric field in THz frequency. The E7 LC parameters have positive as well as negative values of order parameter and birefringence under the influence for an electric field. The director angle of E7 LC shows fast fluctuations above the angle θ=45° and due to rapid change in the orientation of molecules, fast electro-optical switching devices based on E7 LC can be designed. The refractive index of the E7 LC maintains stability in THz frequency.

Single point incremental forming (SPIF) process has the capability to form small/medium-sized part generally used for rapid prototyping applications in automotive and non-automotive industry. Although considerable research has been conducted over the past decades on the formability of various aluminum alloy using SPIF process. This paper presents an investigation on the behavior of AA1200 H14 aluminum alloy by means of SPIF process. The formability of AA1200 H14 in terms of maximum formable wall angle has been evaluated using varying wall angle conical frustum (VWACF) profile. Taguchi method based design of experiment, analysis of variance (ANOVA), signal-to-noise ratio (S/N Ratio) have been employed to identify the significant parameters affecting formability. Utilizing the experimentally acquired results, the S/N ratio (dB) graphs have been drawn and identified the optimal parametric combination for maximizing the wall angle. Further, the formability of the parts has also been evaluated using forming limit curve. The changes in microstructure due to incremental deformation have been studied through scanning electron microscopic analysis.

An investigation of the interaction of 5CB and 6CB liquid crystals along with their dimer configurations in different conformations. The total energy, thermal energy, HOMO-LUMO Gap, dipole moment, polarizability, constant volume heat capacity, entropy, zero-point energy (ZPE), and enthalpy of the different configurations of 5CB and 6CB liquid crystal dimers are affected during the molecular interaction. The different interaction properties of 5CB, 6CB, and 5CB-6CB dimers studied in parallel and antiparallel conformation with the help of density functional theory method lc-blyp by NWChem software package. The 5CB and 6CB liquid crystal dimers have the least dipole moment and negative entropy in the antiparallel conformation. The cross conformation of 5CB liquid crystal dimer (5CB-5CB) has the least isotropic polarizability; however, the parallel conformation of 5CB liquid crystal dimer has the highest isotropic polarizability. The isotropic polarizability is minimum in the antiparallel conformation of 6CB liquid crystal dimer (6CB-6CB), while isotropic polarizability is maximum in the parallel conformation of 6CB liquid crystal dimer. The 5CB liquid crystal dimer and 6CB liquid crystal dimer have minimum negative interaction energy in the antiparallel conformation, but 5CB-6CB liquid crystal dimer has positive interaction energy for all the possible conformations.

Materials plays important role for survival of any manufacturing industry. Composite materials replace the conventional materials because of their high specific strength, strong damping capacity and high specific modulus. In modern era, natural fiber reinforced polymer composites came into light because of promising properties of natural fibers such as light weight, water resistance, high impact strength, environment friendly etc. In this study, different types of natural fibers that can be used as reinforcement in polymer composite are discussed. Various methods of production and steps involved in processing of natural fiber reinforced composite are presented. Then, mechanical and tribological properties of these composites are reviewed and presented. The different applications of natural fiber reinforced polymer composite are also discussed.

The present work focused on the reduced graphene oxide contains a minimum of six oxygen atoms for the higher dipolar strength. The ionization potential and electron affinity decreased only for the six oxygen atoms based graphene. The six oxygen atoms based graphene have the highest dipole moment. The reduced graphene has 0.25 eV bandgap, which is very suitable for electron transfer. The six oxygen atoms based graphene leads to the least gauge including atomic orbital (GIAO) rotational tensor; however, it has the highest isotropic polarizability difference, diamagnetic susceptibility tensor difference, paramagnetic susceptibility tensor difference, and total susceptibility. The C-C bond length has increased only for the six oxygen atoms based graphene.

Palladium nanoparticles (Pd NPs) of different shapes and sizes have been synthesized by reducing potassium tetrachloropalladinate(II) by l-ascorbic acid (AA) in an aqueous solution phase in the presence of an amphiphilic nonionic surfactant poly ethylene glycol (PEG) via a sonochemical method. Materials have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray soectrscopy (EDX), Fourier transform infrared (FTIR), surface-enhanced Raman spectroscopy (SERS), particle distribution, and zeta potential studies. Truncated octahedron/fivefold twinned pentagonal rods are formed at room temperature (RT) (25 °C) while hexagonal/trigonal plates are formed at 65 °C. XRD results show evolution of anisotropically grown, phase-pure, and well crystalline face-centered cubic Pd NPs at both temperatures. FTIR and SERS studies revealed adsorption of ascorbic acid (AA) and PEG at NP’s surface. Particle’s size distribution graph indicates formation of particles having wide size distribution while the zeta potential particle surface is negatively charged and stable. The truncated octahedron/fivefold twinned pentagonal rod-shaped Pd NPs, formed at RT, while thermally stable and kinetically controlled hexagonal/trigonal plate-like Pd NPs, evolved at higher temperature 65 °C. The obtained Pd NPs have a high surface area and narrow pore size distribution. To predict protein reactivity of the Pd cluster, docking has been done with DNA and lung cancer-effective proteins. The cytotoxicity of the Pd NPs has been screened on human lung cancer cells A-549 at 37 °C. The biological adaptability exhibited by Pd NPs has opened a pathway in biochemical applications.

In this paper, we have investigated the optical properties of one-dimensional periodic structure of dielectric materials with defect of liquid crystal (LC) sandwiched with two silver (Ag) layers. The transmission, reflection and absorption properties of considered periodic structure have calculated theoretically using transfer matrix method (TMM). Our study reports that the tunability of absorption defect peak of the defect periodic structure is achieved by the variation in the incident angle of electromagnetic wave. The obtained result suggests that such defect periodic structure may be used as tunable sensor and filter devices.

The homologous series of MBC liquid crystals (LCs) show re-entrant nematic phase (chiral nature or adverse order) under the external electric field in the THz frequency range. The MBC LCs show the phase conversion from isotropic to nematic and subsequently, nematic to isotropic with the variation in electric field and length of alkyl chain in the molecular structure. The negative order parameter is decreased and the positive order parameter of the MBC series is decreased with the length of the alkyl chain of the molecular structure. The positive values of the birefringence of MBC series are reduced; however, adverse birefringence approximately remains constant. On account of the director angle, a short alkyl chain has smaller values, but after 5 MBC, all the molecules are parallel to the applied electric field and maintain a large perspective θ = 90. The refractive index of MBC increases with the extension of the alkyl chain length in the structure. The abstract image of the MBC LC series indicates the phase variation of the MBC series and the band gap of the nematic phase MBC is also affected by the applied electric field.

In the present work, we have calculated the electro-optical effect of the I52 (4-Ethyl-2-fluoro-4'-[2-(4-pentyl-cyclohexyl)-ethyl]-biphenyl) liquid crystal (LC) molecules under the influence of an external electric field in the THz frequency region. The electro-optical calculation has been performed with the help of a theoretical model which is developed for the organic compounds (liquid crystal), and also suitable for the terahertz (THz) device application. The theoretical model gives the electro-optical properties and correlates with experimental evidence. The birefringence, order parameter, refractive index, dipolar strength, and HOMO-LUMO of the I52 molecules have been calculated theoretically. By increasing the electric field on the molecules, the order parameter and birefringence show positive as well as negative values. The I52 LC molecule behaves as an insulator due to having a large bandgap (5.08 eV).

Fiber-reinforced composite are widely used materials in today’s world. They have various applications in modern world viz. aircrafts, automobiles, construction industries, etc. Fiber-reinforced composites consist of matrix and fiber. The mechanical properties of composites depend upon various factors such as type of fiber, fiber length, and concentration of fiber. In this paper, micromechanical analysis of natural fiber-reinforced composite is presented. The experimental analysis of the composites is costly and time consuming. So, numerical analysis of composites is carried out. The analysis of composites is a tedious job due to the heterogeneous nature of composites. To overcome this, RVE model-based analysis is used which models the composite as homogeneous mixture of matrix and reinforcement by taking the properties of matrix and fiber as input. This analysis is carried out using DIGIMAT software and the results obtained are validated using rule of mixture model. From the results obtained, it is found out that mechanical properties enhance with the increase in weight concentration of fibers.

In this work, we present the effect of electric field on 4-(trans-4 $$'$$ -n-alkyl-cyclohexyl) isothiocyanate-benzene (nCHBT) liquid crystal (LC) molecules. Under the influence of an electric field, the birefringence exhibits the even–odd effect while order parameter, HOMO–LUMO gap, magic angle, isotropic polarisability, range of director angle and the refractive index do not exhibit any even–odd effect. The extension of the alkyl chain length of the nCHBT liquid crystal molecule exhibits the even–odd effect for the dipole moment and temperature from nematic to isotropic phase transition while the HOMO–LUMO gap remains constant. Still, order parameters, isotropic polarisability and refractive index have continuously increased. The odd carbon atom numbers present higher values than the even carbon atom numbers of the alkyl chain for the phase transition temperature. The nCHBT LC molecule expresses the order parameter, and birefringence is reciprocal to each other. For the whole series, there is an increase in order parameter, and a decrease in birefringence. The influence of the external electric field is an alternative to the temperature for the optical parameter of nCHBT LC.

The homologous series of the organic compound N(p-n-heptyloxy-benzylidene) p-toluidine (7O.m) expresses the odd–even effect under the influence of an external applied electric field by density functional theory (DFT) methods. The dipole moment, order parameter, and birefringence express an odd–even effect. At the same time, the Homo–Lumo gap and isotropic polarizability do not exhibit any odd–even effect under the influence of an external applied electric field. The Homo–Lumo gap remains constant for the homologous series of 7O.m (m = 1–10). The isotropic polarizability and refractive index continuously increase with an extension of alkyl chain length. The DFT methods (B3LYP and M062X) exhibit the same nature of optical characteristics for all the series but with different values.

Copper nanowires of 50 nm diameter have been successfully fabricated via electrodeposition using commercial polycarbonate membrane of pore diameter 50 nm and thickness 10 µm as template. The morphology of wires and crystal structure of material have been analysed by field emission scanning electron microscopy and X-ray diffraction respectively. Nanowires are found to be vertically aligned with cylindrical geometry and thoroughly uniform in diameter. X-ray diffraction pattern exhibit the face centred cubic structure of prepared nanowires. The lattice constant and crystallite size are found to be 3.605 Ȧ and 31.5 nm respectively. I-V characteristics indicate the ohmic behaviour of prepared nanowires. Electrical conductivity is estimated to be 2.02 × 107 Ω−1m−1.

In this study, tellurium nanowires were electrodeposited into the polymer membranes from aqueous acidic bath containing HTeO2+ ions. The field emission scanning electron microscopy (FESEM) images confirmed the formation of uniform and straight nanowires. The influence of 110 MeV Ni8+ ion irradiation induced defects on the structural, optical and electrical properties of as–deposited tellurium nanowires were examined using X-ray diffraction (XRD), UV–visible absorption spectroscopy and current–voltage (I–V) measurements. The XRD data depicted the hexagonal phase of tellurium nanowires and further revealed a variation in the intensity of diffraction peaks of ion irradiated nanowires. Williamson–Hall (WH) analysis is used for convoluting the size and microstrain contributions to the width of diffraction peaks. Tellurium nanowires exhibited a distinct absorbance band in the visible region at 686 nm, while this was absent in bulk tellurium. Electrical properties of nanowires are explored on the basis of I–V curves, which revealed a significant increase in the electrical conductivity of irradiated nanowires. A possible mechanism for the enhanced electrical conductivity is the increase in carrier concentration due to thermally excited defects. The defects produced by ion irradiation play a vital role in modifying the properties of semiconducting nanowires.

In this work, the dielectric property of a nanocomposite (NC) consisting of silver nanoparticle and E7 liquid crystal (LC) has been investigated theoretically at different temperatures. The study shows that the surface plasmon resonance (SPR) and filling fraction of the silver nanoparticle significantly change the dielectric property of the NC. To study the optical property of the defective periodic structure, the NC was considered as a defect layer in a semifinite one-dimensional periodic structure (1DPS) of $$\hbox {TiO}_{{2}}$$ and $$\hbox {SiO}_{{2}}$$ layers, i.e. ( $$\hbox {TiO}_{{2}}{\vert }\hbox {SiO}_{2})^{5}{\vert }\hbox {NC}{\vert }(\hbox {TiO}_{{2}}{\vert }\hbox {SiO}_{2})^{5}$$ . The optical properties of the 1DPS with the NC as the defect layer have been studied by the simple transfer matrix method (TMM). Moreover, the transmission and absorption characteristics of the 1DPS in the presence of silver nanoparticle in the NC have been studied with different orientations of the LC molecule.

This paper reports the theoretical investigation of transmission properties of a one-dimensional periodic layer consisting of SiO2 and TiO2 layers with anisotropic liquid crystal (LC) and LiNbO3as defect layers with the variation of incident angle, temperature and applied a voltage across the crystal. The optical transmission properties of the considered structure have been calculated by using a 4 × 4 transfer matrix method (TMM). The transmittance of the considered structure with LC and LiNbO3as defects gives rise to defect mode wavelength peak inside the bandgap region. The transmittance peak of the defect mode shows the blue shift in the transmission of periodic structure for TE and TM polarizations with incident angle, applied voltage, and temperature. Further, the transmission behavior of defect modes and terminal wavelengths are analyzed with the variation of incident angle and temperature. The transmission of the considered structure has found the tunable characteristics due to the presence of anisotropic defect layer LC and LiNbO3. The one-dimensional periodic layer consisting of SiO2 and TiO2 layers with the defect layers of anisotropic materials, liquid crystal (LC) and LiNbO3, as may be used to design optical switching devices. Keywords: Anisotropic liquid crystal (LC), LiNbO3, 4 × 4 transfer matrix method (TMM), Blue shift

This paper is concerned with the development of model for the finite element analysis of the conical space adapter which is subjected to axial compression. It also provides the information about the parameters required for generating the input for modelling the structure. Analysis is performed using Ansys, i.e. software for finite element analysis. The results of analysis include the behaviour of the adapter under axial compression, e.g. stresses in the helical and circumferential ribs, displacement of the space adapter, critical buckling load and global buckling. Modal analysis has been carried out to study the modes of vibrations and obtain the frequency of vibration of the structure.

The homologous series of APAPA (anisylidene-para-amino-phenyl-acetate) liquid crystal (LC) express the odd-even effect under the influence of an electric field in THz frequency region. The homologous series revealed an odd-even effect under the impact of temperature. The electron affinity and ionization potential have exhibited an odd-even effect with the extension of the alkyl chain length. The birefringence has expressed an odd-even effect under the influence of an extraneous electric field. The homologous series has positive as well as the negative orientation of the birefringence, which is suitable for electro-optical application devices. The order parameter and refractive index have continually increased with an expansion of alkyl chain length. The director angle remains constant at θ = 90° for the whole series of LC. The extraneous influence of the electric field has correlated with the impact of temperature variation.

In the present paper, we investigated the change in the properties of copper nanowires under the irradiance of 80 MeV Si 7+ ion beam. The nanowires were electrodeposited in the cylindrical pores of the track-etched polycarbonate membranes. The phase, morphology and optical absorbance of the fabricated nanowires were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV–visible spectroscopy, respectively. The XRD study showed a face centered cubic crystal structure of copper nanowires. Further measurements with FESEM revealed that nanowires were continuous, aligned with uniform diameter having high aspect ratio. The XRD spectra of irradiated nanowires indicated an improved crystalinity at low ion fluences while it declines at higher ion fluences. The optical absorbance properties of the irradiated copper nanowires were also examined. The absorption spectra exhibited a peak at 568 nm which was attributed to the surface plasmon resonance. A significant increase in absorbance after irradiation accounts for the possibility of defects formation. The electrical properties measured from I – V characteristics showed an increase in resistivity of irradiated nanowires.

In present work, we report the N-(p-hexyloxy-benzylidene)–p-toluidine (HBT) liquid crystal (LC) molecule having maximum absorbance due to the O–C stretching (carbon atom of benzene ring) during the intermolecular interaction. Under the expansion of an external electric field, the HBT LC having nematic to smectic phase stability with adverse (negative values) order parameter and birefringence. The refractive index expresses stability in the nematic, smectic, and isotropic phases. The director angle maintains stability for the nematic phase in the adverse order and smectic phase stable in positive order.

Herein, we investigate a hydrogen-bonded liquid crystal compound, namely 4-(Heptyloxy) benzoic acid (7OBA), and its composites by dispersing Graphene and reduced graphene oxide (rGO) flakes into an optimized concentration. The pristine 7OBA and its composites are characterized by different instrumental techniques like polarized optical microscopy, differential scanning calorimetry (DSC), dielectric, UV-visible, and Fourier-transform infrared (FTIR) spectroscopy. DSC thermograms of the 7OBA composites evince the down-shift in the smectic C−nematic and nematic−isotropic phase transition temperatures. The polarized optical micrographs (POMs) of composites reveal the homogeneous distribution of graphene and rGO flakes in the 7OBA compound without any aggregation. The π-π* transitions in phenyl ring of 7OBA compound and π-π* transitions in C C bonds of graphitic materials are superimposed to each other providing an enhanced UV absorbance nearly at 255 nm for the composites. The presence of graphene and rGO enhances the tan δ and electrical conductivity of the composites, whereas dielectric anisotropy, Δϵ, reduces as a function of temperature in comparison to the pristine 7OBA compound. The sign inversion of Δϵ has been observed for the 7OBA/rGO composite which has been explained via dipole−dipole interactions. The I−V behavior of the pristine 7OBA compound yields the ohmic I−V curve with a non-zero current at 0 V attributing to the pseudocapacitance effect, whereas, after the dispersion of graphene and rGO flakes, nonlinear diode like I−V curves having a hundred times larger conduction current were obtained. Furthermore, the molecular interactions have been analyzed by the FTIR which confirms the formation of hydrogen bonding in the 7OBA/rGO composite. At last, these experimental findings are compared with the simulated results by DFT. The experimental and theoretical simulations are commensurable to each other. The studied composites have shown their vital applications in nonlinear electronics.

In this paper, we investigate tunable transmission characteristics of a one-dimensional periodic structure (1DPS), designed with periodic dielectric materials containing a nematic liquid crystal (NLC) as a defect layer, on the basis of orientation and re-orientation of LC molecules. The nonlinear differential equation for the director of the liquid crystal under the light field is solved numerically. The relation between the liquid crystal director and the intensity of the electromagnetic wave (EMW) is derived. Transmittances of the liquid crystal defect layer in the 1DPS are calculated with the variation of the intensity of the incident wave and liquid crystal director tilt angles. By varying the director tilt angle of the liquid crystal molecules as well as the incident angle of the EMW, the shifting of the transmitted defect mode wavelengths is studied. Such study is helpful to understand how orientation and reorientation of the molecules affect the transmittance of the considered periodic structure when the EMW interacts with an embedded liquid crystal as a defect layer in the 1DPS of dielectric materials. Such photonic structure of dielectric materials with the liquid crystal layer as a defect layer can be used to fabricate bistable switches, optical filters, feedback lasers, etc.

Here, we examined ionic current behavior of conical nanopores at different pH and a fixed ion concentration of potassium halide (KCl). Conical shaped nanopores have been developed by chemical etching technique in polyethylene terephthalate (PET) membrane/foil of thickness 12 micron. For this we employed a self-assembled electrochemical cell having two chambers and the foil was fitted in the centre of cell. The nanopores were produced in the foil using etching and stopping solutions. The experimental results show that ionic current rectification (ICR) occurs through synthesized conical nanopores. Further, ion current increases significantly with increase of voltage from the base side of nanopores to the tip side at fixed pH of electrolyte.Here, we examined ionic current behavior of conical nanopores at different pH and a fixed ion concentration of potassium halide (KCl). Conical shaped nanopores have been developed by chemical etching technique in polyethylene terephthalate (PET) membrane/foil of thickness 12 micron. For this we employed a self-assembled electrochemical cell having two chambers and the foil was fitted in the centre of cell. The nanopores were produced in the foil using etching and stopping solutions. The experimental results show that ionic current rectification (ICR) occurs through synthesized conical nanopores. Further, ion current increases significantly with increase of voltage from the base side of nanopores to the tip side at fixed pH of electrolyte.

In the present paper, 80 MeV Si7+ ion beam-induced changes in selenium nanowire arrays, fabricated on copper substrates, have been examined. The nanowire arrays were electrodeposited into polymer membranes using template method. The X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV–visible spectroscopy have been used to study the ion-induced effects in fabricated nanowire arrays. The XRD and FESEM results confirmed the formation of selenium nanowire arrays with trigonal structures. An intensity variation in the XRD peaks is observed for irradiated nanowires at different ion fluences. The band gap energy of the irradiated nanowire arrays was found to reduce compared with the pristine case. The irradiation of semiconducting selenium nanowires enhances the electrical conductivity. The current–voltage characterizations also confirm an enhancement in electrical conductivity of selenium nanowire arrays with an increase in ion fluence. This study is anticipated to greatly facilitate the design and development of nanodevices-based semiconductor nanowires which can be utilized even in the harsh environment.

We report the fabrication of highly ordered arrays of tellurium nanowires and investigate their electrical, optical and structural properties. The tellurium nanowire arrays were synthesized by electrochemical deposition via a template method and characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV–Visible spectroscopy. The XRD and FESEM characterizations confirm the formation of a dense crop of tellurium nanowire arrays with hexagonal phase. The intense crystalline peak corresponding to the (100) plane observed in the XRD spectra suggests a preferential growth of wires along the [001] direction. The crystallite size and micro-strain effect were estimated by Williamson–Hall (WH) analysis. The average crystallite size and lattice strain extracted from WH plot were found to be ∼34 nm and 0.0044, respectively. Further, electrical properties of the arrays of nanowires were examined using a two-probe method. The current–voltage curve of the tellurium wires exhibits a non-linear behavior and a double diode-like characteristic, which signifies their novel applications in future nanodevices.

Xanthan gum is a biopolymer produced by Xanthomonas sp. XC6. In this study, xanthan gum is produced from potato starch using a stepwise bioprocess design. Potato starch is hydrolyzed using Bacillus sp. having amylase activity and 30.2 g/L reducing sugar was released, while Xanthomonas sp. XC6 can release only 14.5 g/L. Bacillus sp. hydrolyzed potato starch extract was further used as a carbon source for xanthan gum biosynthesis using Xanthomonas sp. XC6. Yeast extract acts as the best nitrogen source, and 10.0 g/L xanthan gum was recovered. Downstreaming process after stepwise bioprocess resulted in 17.4 g/L xanthan gum production, which is 2.8 times higher as compared to single step process. Electronic supplementary material The online version of this article (doi:10.1007/s13205-014-0273-2) contains supplementary material, which is available to authorized users.

The template strategy combined with electrodeposition technique has been used to produce copper nanowires in the cylindrical pores of track-etched polycarbonate membranes. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV–visible spectroscopy have been used to characterize as-prepared copper nanowires. XRD study shows the face centered cubic crystal structure of copper nanowires. Williamson–Hall (WH) analysis has been used to determine the crystallite size and microstrain induced due to lattice deformation. FESEM results reveal that copper nanowires are continuous, well aligned with uniform diameter and having high aspect ratio. The optical absorption spectra exhibit a strong peak at 568 nm attributed to the surface plasmon resonance. The current–voltage (I–V) characteristics show an ohmic behavior of the fabricated copper nanowires. The increase in resistivity of nanowires than that of bulk counterpart has been attributed to the surface and size effects in nanowires and explained in the light of Fuchs–Sondeimer and Mayadas–Shatzkes models.

Large scale selenium nanowires have been prepared into the pores of polycarbonate track-etched membrane by template electrodeposition. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV–Visible spectroscopy have been used to characterize as-prepared crop of selenium nanowires. XRD and FESEM studies confirmed the formation of dense crop of selenium nanowires with trigonal phase. The spectra exhibited a highly crystalline peak corresponding to (100) plane suggesting a preferential growth along [001] direction. Williamson–Hall analysis has been used to determine the crystallite size and micro strain induced due to lattice deformation. The band gap of as-prepared selenium nanowires has been found to be 1.76 eV and of the direct type of transition. The blue shift observed in the optical band gap of selenium nanowires has been attributed to quantum size effect in semiconductor nanowires. Electrical properties of selenium nanowires have been examined using two probe method and showed double diode like current–voltage characteristics. The possible reaction mechanism of the formation of selenium nanowires has also been discussed.

This paper reports the tunable transmission properties of asymmetric one-dimensional periodic structure (1DPS) composed of SiO2 and anisotropic metamaterial (AMM) layers with defect of liquid crystal (LC) sandwiched by two SiO2 layers, i.e., (SiO[Formula: see text]AMM)[Formula: see text]SiO[Formula: see text]LC[Formula: see text]SiO[Formula: see text](SiO[Formula: see text]AMM)3 using the transfer matrix method (TMM). We have studied the optical properties of the periodic structure (SiO[Formula: see text]AMM)3 [Formula: see text]SiO[Formula: see text]LC[Formula: see text]SiO[Formula: see text](SiO[Formula: see text]AMM)3 with a different incident angle of the electromagnetic wave for particular director angle of LC molecules. The tunability of the transmission property of the considered 1DPS shows that the transmittance depends upon the orientation of LC molecules. Such an asymmetric periodic structure (1DPS) composed of SiO2 and AMM with a defect of LC sandwiched by two SiO2 layers, (SiO2 [Formula: see text]AMM)[Formula: see text]SiO[Formula: see text]LC[Formula: see text]SiO[Formula: see text](SiO[Formula: see text]AMM)3, may be used as a tunable optical filter and bi-stable device.

Single point incremental forming (SPIF) is an emerging sheet metal forming process which is used to build a prototype of sheet metal parts with complex geometries. Geometrical inaccuracies of the formed parts are the significant obstruction in the commercialisation of this process. In this paper, Taguchi method and analysis of variance have been used to comprehensively study the effect of four process parameters such as step depth, tool diameter, spindle speed and feed rate on the geometrical error in the form of average radial error of the formed part. Parametric analysis and formulation of an empirical model for predicting the amount of geometric error in this process have been discussed. From the Taguchi method and analysis of variance, the optimal results are identified adequately and proficiently to produce a minimum geometric error.

The control of ionic transportation inside the multi asymmetric conical nanopores in polyethylene terephthalate (PET) membrane was investigated. The conical nanopores were prepared by chemical etching in irradiated PET foil using etchant (9 M NaOH) and stopping solution (1 M NaCl [Formula: see text] 1 M HCOOH). The behavior of ionic current was recorded under stepping voltage [Formula: see text]2[Formula: see text]V to [Formula: see text]2[Formula: see text]V at different molar concentrations of potassium halides (KCl, KBr and KI) under symmetric bathing condition in electrochemical cell. It is found that the presence of multiple ionic species and the occurrence of counterion condensation of charge regulated polyelectrolyte play an effective role in ionic current rectification (ICR). The electrical conductance of conical nanopores may be estimated by measuring the ionic current rectification properties of track-etched nanopores. The charge transport properties vary with molar concentration and pH of electrolyte. Moreover, ICR may be used as a voltage gating phenomena with wide technological applications.

Selenium nanowires were fabricated by electrodeposition technique. Polycarbonate track-etched membrane with cylindrical nanopores was used as template. Scanning electron microscopy was employed to characterize the morphology and the size of fabricated selenium nanowires. The optical properties of the grown nanowires have been determined using UV–visible spectroscopy.

Copper nanowires have been synthesized successfully using template assisted electrodeposition technique. Commercial polycarbonate membrane (Whatman, Japan) having pore diameter 100 nm, thickness 10 μm and pore density 107 pores/cm2 was used as template. Scanning electron microscopy and X‐ray diffraction techniques were used to characterize the synthesized copper nanowires. XRD and SEM results reveal that polycrystalline copper nanowires were obtained with fcc lattice structure having diameter equal to the diameter of the template used.

Diffraction at a low frequency grating is used for the measurement of focal length of a positive lens.