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Solid polymer electrolytes containing methylcellulose:dextran (MC-DEX), ammonium hexafluorophosphate (NH4PF6), and glycerol have been prepared via the solution cast method. Various techniques have been used to characterize the prepared electrolyte samples. Fourier transform infrared spectroscopy (FTIR) analysis revealed the interaction between polymers and electrolyte components. According to the electrical impedance spectroscopy (EIS), the highest conducting plasticized system achieves a conductivity of 6.71 × 10-4 S cm−1 at ambient temperature. The mobility, number density, and diffusion coefficient of ions were measured using both FTIR and EIS methods, and it was found that their values rise as the amount of glycerol increases. Polarization due to ion migration is responsible for the high value of dielectric parameters. According to transference number measurement (TNM), the transport ion (tion) is 0.92, verifying that the ions are the primary charge carriers. The electrochemical stability window of the maximum conducting plasticized system is 1.58 V, based on linear sweep voltammetry (LSV) analysis. The electrical double-layer capacitor (EDLC) device is fabricated using the highest conducting plasticized system. The cyclic voltammetry (CV) curve is roughly rectangular in shape and with no presence of Faradaic peaks with its specific capacitance of 32.69F/g at 10 mV/s.

Hydroxyethyl cellulose (HEC) doped with 3 wt% erbium nitrate film was prepared by casting from solution. The effect of plasma treatment on optical properties of composite film was investigated. The optical absorbance was measured in the wavelength region of 200–800 nm. . Electronic transition was proved to be direct allowed for pristine and plasma treated film. Tauc’s plots were used to determine the optical band gap (Eopt) of the samples under study. The energy gap was 5.30 eV for untreated composite film and the treated samples at 10, 20 and 30 min have lower values of optical band gap, 5.22, 5.20 and 4.90 eV respectively. It was also found that the Urbach energy values (Ee) were decreased under different plasma treatment times. It begins with 1.46 eV for untreated sample till it reaches 0.72 eV for 30-minute treated sample. Wemple–DiDomenico model parameters such as, oscillator energy, dispersion energy and zero-frequency refractive index values were calculated and their variations with plasma were studied. The color parameters for composite film are noticeably affected under plasma treatment.

Penta-glasses with a 59B2O3–29SiO2–2LiF–( $$10-x$$ ) ZnO– $$x$$ TiO2 composition with the melt-quench techniques were prepared. X-ray diffraction was used to examine the nature of fabricated glasses. The changes in the structure of fabricated glasses were studied by Fourier-transform infrared spectroscopy spectra. The molar volume of fabricated glasses reduces as the density increases. The mechanical characteristics of these glasses were evaluated. Besides, for the studied glasses, Phy-X/PSD and XCOM program were used to investigate the radiation shielding efficiency. These glasses were found to have an abnormal attenuation, structural, and density relationship. Glasses' mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), half-value layer (HVL), tenth value layer (TVL), and effective atomic number (Zeff) were designed to simulate gamma photon energies ranging from 0.015 to 15 meV. MAC values determined with Phy-X/PSD and XCOM were compared and were observed in good agreement with the other.

Glasses with the chemical composition of 52B2O3 – 12SiO2–26Bi2O3 – (10 − x)TiO2 - xY2O3, :(0 ≤ x ≤ 10) prepared using the melt-quench method. The goal of this study is to investigate the structural, mechanical, and radiation shielding characteristics of these samples. XRD analysis has explored the nature of the glass system. Molar volume obtained reduced while the density denotes increased in the present system. As the molar volume decrease inter-ionic distance, polaron radius, inter-nuclear distance, and Y-Y separation of the investigated glasses decreased. The mechanical characteristics depend on the glass structure of the current glasses sample. Ultrasonic velocities and elastic moduli (experimental and theoretical) for these glasses obtained they were observed to get enhanced. The radiation shielding efficiency was investigated by Phy-X/PSD software. The mass attenuation coefficient, mean free path, half-value layer, tenth value layer, and effective atomic number of glasses have been designed to simulate gamma photon energies between 0.015 and 15 MeV.

The poverty-stricken population cannot withstand the shocks of global warming and can hardly pay the soaring expenditure of fossil fuels whose reservoirs are already approaching the threshold limit. These adventures guided the researchers towards water oxidation as a source of energy. In this study, a metal-organic framework (MOF)-based material was fabricated and catalyzed the lethargic oxygen evolution reaction (OER). The synthesized material is characterized with different analytical techniques to confirm structural, morphological and textural properties. Its huge surface area (87 m2/g) rendered it a promising material to carry the OER. It exhibited shallow onset potential that is, 1.40 V vs. RHE and displayed an exceptionally low overpotential of 1.42 V vs. RHE to reach the benchmark current density (10 mA/cm2) with remarkably small Tafel slope that is, 34 mV/dec. It surpassed the state of the art electrocatalyst for OER, that is, IrO2 and RuO2 in efficiency as well as in stability.

Strontium-substituted spinel ferrites were prepared using the sol–gel method. The sample’s chemical formula was Cu1–xSrxFe2O4 (0.00, 0.20, 0.40, 0.60, 0.80 and 1.00). A cubic structure was discovered through X-ray diffraction (XRD) analysis. The lattice, constant, X-ray density and other structural parameters were increased with the substitution of strontium ion due to its larger ionic radius as compared with the ionic radius of manganese. It was discovered that the addition of strontium ions increased both activation energy and dc resistivity, whilst the decrease in resistivity with increasing temperature proved the semiconducting nature of samples. There was an abysmal disparity between the coerciveness and magnetization values. The permittivity was decreased with the addition of strontium ions. The low perittivity and high specific resistance suggested that prepared samples are suitable for high-frequency applications.

Nanocomposites films based on Poly Vinyl Pyrrolidone/Chitosan (PVP/Chitosan) filled by Vanadium pentoxide nanoparticles (V2O5 NPs) have been produced via solution casting method. Vanadium pentoxide nanoparticles were scattered direct in the blend of PVP/Chitosan by one-potential laser ablation technique. The main purpose in using Vanadium pentoxide nanoparticles is to modify the structural, optical, and electrical characterization of PVP/Chitosan composite. The complexation between Vanadium pentoxide nanoparticles and PVP/Chitosan has been approved via XRD and FTIR-ATR analyses. The average size of V2O5 was 20.5 nm. After the scattering by vanadium pentoxide nanoparticles, AC conductivity improved. The values of dielectric constant and dielectric lose decreased as the frequencies enhanced. At lower frequency, greater values of dielectric constant and dielectric lose have been detected due to the mobile charges inside the polymeric backbone. The fabricated PVP/Chitosan/V2O5 NPs films could be suggested for electrical and optoelectronic applications.

The solution cast process is used to set up chitosan: dextran-based plasticized solid polymer electrolyte with high specific capacitance (228.62 F/g) at the 1st cycle. Fourier-transform infrared spectroscopy (FTIR) pattern revealed the interaction between polymers and electrolyte components. At ambient temperature, the highest conductive plasticized system (CDLG–3) achieves a maximum conductivity of 4.16 × 10−4 S cm−1. Using both FTIR and electrical impedance spectroscopy (EIS) methods, the mobility, number density, and diffusion coefficient of ions are measured, and they are found to rise as the amount of glycerol increases. Ions are the primary charge carriers, according to transference number measurement (TNM). According to linear sweep voltammetry (LSV), the CDLG–3 system’s electrochemical stability window is 2.2 V. In the preparation of electrical double layer capacitor devices, the CDLG–3 system was used. There are no Faradaic peaks on the cyclic voltammetry (CV) curve, which is virtually rectangular. Beyond the 20th cycle, the power density, energy density, and specific capacitance values from the galvanostatic charge–discharge are practically constant at 480 W/Kg, 8 Wh/Kg, and 60 F g−1, for 180 cycles.

Poly (ethyl methacrylate) (PEMA) - cellulose acetate propionate (CAP) blend film was prepared using the cast technique. A Q-switched Nd: YAG laser beam with a wavelength of 266 nm, a pulse duration of 10-ns, a repetition rate10 Hz and 0.018 J/cm2 fluence was used to irradiate the prepared film. The optical absorption of pristine and irradiated sample was studied within 200–500 nm wavelength region. The absorbance increases with laser irradiation time over the full wavelength region which is attributed to an increase of the crosslinking network. Examining Tauc plots revealed a transition of the direct allowed type with optical energy gap value of 4.92 eV for the pristine blend film which has decreased to 4.30 eV after laser irradiation for 90 min. The refractive index, finesse coefficient, dielectric function, Brewster, and critical angles demonstrated dispersion in the 200–500 nm wavelength range.

Nitrogen doped graphene modified WO3 nanocomposites were synthesized through an effective methodology. The prepared photocatalysts were employed as active candidates for degradation of highly toxic organics i.e., 2, 4 dichloro phenol (2, 4-DCP) and methyl orange (MO). XRD profile of N-graphene showed complete reduction of GO into N-graphene. All diffraction peaks of WO3 along with N-graphene indicated monoclinic phase of WO3. SEM and TEM images of 3.0% N-graphene/WO3 have demonstrated the mixed morphology of irregular massive rod like blocks and round shaped particles of WO3 distributed on cracked sheets of N-graphene. Nitrogen defects in graphene altered zero band gap semi-metallic graphene to semiconducting material and increased the absorption edge of N-graphene/WO3 nanocomposites towards visible region as studied in DRS analysis. FTIR and Raman studies showed the strong connection between N-graphene and WO3 by making W − O − C surface linkage. The noticeable reduction in PL emission peaks of 3.0% N-graphene/WO3 indicated obvious separation of photo induced charge carriers. The study of radical scavengers suggested that holes (h+) and •OH are the main elements for the decontamination of both MO and 2, 4-DCP. XPS analysis shows all possible C − N bonding configurations in 3.0% N-graphene/WO3. 3.0% N-graphene/WO3 composite showed the maximum photo degradation of MO ( ~ 94.0%) and 2, 4-DCP ( ~ 81.0%). The synergism between N-graphene and WO3 results into more sporty sites on catalyst and restoring of sp2 structural defects in N-graphene lattice improve the transportation of charge carriers during photocatalysis. This work provides innovative strategies for designing the N-graphene/semiconductor nanosystems with enhanced photocatalytic phenomena in the environmental cleanup remedies.

In this research, effects of anodization parameters on the growth behavior and top morphology of TiO2 nanotubes are investigated. Five TiO2 nanostructures with different top morphologies, including nanopores, nanotubes, nanohexagons, nanonet and nanograss, are obtained through an electrochemical anodization of Ti foil, by varying the anodization parameters, e.g., anodization time, anodization temperature and deionized water contents. Dye sensitized solar cells (DSSC) based on the photoanodes fabricated with the TiO2 nanohexagon morphology show the highest power conversion efficiency of 5.29% with N719 Dye. Moreover, to further enhance the efficiency of DSSC, modifications of the TiO2 nanohexagons with TiO2 nanoparticles derived from TiCl4 with different molar concentrations are also explored. It is observed that the TiO2 nanohexagons based photoanode treated with 0.2 M TiCl4 shows a maximum efficiency of 6.64% with N719 Dye and incident photon-to-current efficiency (IPCE) of 68%, due to the increased effectiveness in electronic transport and enhanced surface area for N719 dye-adsorption.

Films of TiO2, La-doped TiO2 (La–TiO2), La–TiO2/TiO2 and TiO2/La–TiO2 are prepared by sol-gel (dip coating) route. The structural properties like phase, grain size, dislocation line density, inter-planner distance, and lattice parameters are calculated by X-ray diffractometer (XRD). All films have anatase phase which is good for solar cells application. Film of La-doped TiO2/TiO2 has high grain size. The optical properties like transmittance, absorbance, refractive index, extinction coefficient, dielectric constants and band gap are measured by UV–Vis spectroscopy. The film of La-doped TiO2/TiO2 has low bandgap and high transmittance in visible range making it a good candidate for dye sensitized solar cells (DSSCs). DSSCs from these electrodes are prepared by using electrolyte (iodide/tri-iodide) and dye (N719). 1% La–TiO2/TiO2 based cell has highest open-circuit voltage (0.74 V), Fill-Factor (0.73), short-circuit current density (6.57 mA/cm2), and efficiency (3.53%) as compared to other cells. Low value of bandgap energy, weak recombination rate, improvement in charge transfer rate is mainly responsible to achieve highest efficiency rate (3.53%).

The aim of this study is to synthesize Li1+xAlxTixSn2−2x(PO4) sodium super ion conductor (NASICON) -based ceramic solid electrolyte and to study the effect of dual metal substitution on the electrical and structural properties of the electrolyte. The performance of the electrolyte is analyzed based on the sintering temperature (550 to 950 °C) as well as the composition. The trend of XRD results reveals the presence of impurities in the sample, and from Rietveld Refinement, the purest sample is achieved at a sintering temperature of 950 °C and when x = 0.6. The electrolytes obey Vegard′s Law as the addition of Al3+ and Ti4+ provide linear relation with cell volume, which signifies a random distribution. The different composition has a different optimum sintering temperature at which the highest conductivity is achieved when the sample is sintered at 650 °C and x = 0.4. Field emission scanning electron microscope (FESEM) analysis showed that higher sintering temperature promotes the increment of grain boundaries and size. Based on energy dispersive X-ray spectroscopy (EDX) analysis, x = 0.4 produced the closest atomic percentage ratio to the theoretical value. Electrode polarization is found to be at maximum when x = 0.4, which is determined from dielectric analysis. The electrolytes follow non-Debye behavior as it shows a variety of relaxation times.

In this research, direct band gap polymer composites with amorphous phase, which are imperative for optoelectronic devices applications were synthesized. The solution cast technique was used to produce polyethylene oxide (PEO)/calcium titanate (CaTiO3) nanocomposite (NC) films. The X-ray diffraction (XRD) confirms the growth of amorphous nature within PEO with CaTiO3 addition. The optical band gaps of pure PEO and PEO/CaTiO3 NC films were calculated using analysis of ultraviolet–visible (UV-Vis) spectra. The change in absorption edge toward lower photon energy is evidence of polymer modification. The dispersion behavior of the refractive index of PEO was manipulated to a higher wavelength upon doping with CaTiO3. Upon adding CaTiO3 to the pure PEO polymer, the dielectric constant and refractive index were considerably modified. The band gap shifts from 4.90 eV to 4.19 eV for the PEO incorporated with an optimum portion of 8 wt. % of CaTiO3. The types of the electronic transition in composite samples were specified, based on the Taucs model and the optical dielectric loss. The alteration of UV/Vis absorption spectra of the NC film was considered a suitable candidate to be applied in nanotechnology-based devices. The spherulites ascribed to the crystalline phase were distinguished through the optical microscopy (OM) study.

This study evaluates the physical and chemical effects of the sewerage environment on the corrosion of Portland cement concrete (PCC), sulfur-resistance cement concrete (SRC) and modified Sulfur concrete (MSC), through the carbonation depth measurements and the corrosion of reinforcing steel. The in-situ study showed high resistivity of MSC to the sewerage environment over PCC and SRC. Alkalinity test of PCC and SRC showed neutralization depth of 3.8 mm and 3.2 mm, respectively. Whereas, MSC showed no alkalinity change indicating excellent protection to reinforcement in sewerage environment. Also, the PCC and SRC showed an increase in the number of pores and pores’ size, and connectivity after exposure to the sewerage environment, while insignificant change was observed in the pore system of the MSC.

PolyvinylPyrrolidone (PVP) doped Praseodymium (III) nitrate hexahydrate (Pr(NO3)3.6H2O) composite system has been prepared according to xPr(NO3)3 - (100-x) PVP polymer composite system with x = 0, 10, 20 and 40 wt% using casting technique. X-ray diffraction patterns revealed that there is a level of interaction between polymer and metal nitrate. The optical absorption measurements of the investigated system were done in the wavelength range of 190−1100 nm. A method for curve fitting of absorbance showed optical absorption is due to indirect transition and the energy band gap decreased from Eg = 5 eV for pure PVP film to 3.20 eV for 40 wt% Pr(NO3)3 doped PVP film. The high wavelength refractive index (n∝) and number of carbon atoms per carbonaceous cluster (N) were found to increase noticeably with composition. The dispersion of refractive index and complex dielectric constants were investigated. Color parameters of composite system were calculated in the context of CIE L*u*v* color space.

Carboxymethyl cellulose film doped with 40 wt% nickel chloride ( 6H2O) has been prepared by casting technique. The prepared film sample has been treated with nitrogen plasma at different exposure times. The optical absorption was recorded at room temperature in the wavelength range of 190–2,500 nm. From the absorption edge studies, the values of the Urbach energy (Ee) were found to be 0.99eV in case of the pristine film; however, the Urbach energy values were found to be in the range of 0.72–0.92 eV under different plasma treatment times. These energy values indicate that the model based on random fluctuations of the internal fields associated with structure disorder is preferable and consequently transitions occurred through localized and extended states. Modulation of refractive index and complex dielectric constants has been also studied. Variation of color parameters under effect of the plasma treatment are discussed in the frame work of CIE L* u* v* color space. POLYM. COMPOS., 00:000–000, 2016. © 2016 Society of Plastics Engineers

Clean water is the key element for all living organisms to sustain life. However, due to the rapid industrialization and large increase in the population, the contamination of water resources is important issue occurred globally as well as locally here in Middle East region [[1]]. From past few decades, various techniques for treating the wastewater have been developed. Among others, filtration techniques are a commonly used to eliminate contamination of water caused by various materials such as heavy metals, dyes, oil, bacteria etc. Robust, capable membranes are crucial for effective filtration process and various polymeric materials have been studied in last decades. Among others, polyamides membranes have been used as membranes due to their favourable properties such as good thermal and mechanical stability [[2]], which make them suitable for the designing of fibres, mats and membranes. Compared to many commercially available filtering membranes that are produced by conventional fabrication techniques such as phase inversion technique, the pore size distribution of electrospun fibrous membranes can be conveniently tailored in the range of sub-microns up to a few micrometers via simply adjusting the material and process parameters of electrospinning and related post-processes. In addition, electrospun filtering media are also capable of maintaining a high porosity, which guarantees the high-flux liquid filtration.One of the approach to further improved efficiency, mechanical performance and lifetime of membranes is using various fillers.Nanocelluloses are particularly interesting because of their environmental friendliness, high mechanical performance, flexibility, low-cost, versatility, and tailorable surface functionalities. The size, structure, and functional groups of nanocelluloses are dependent on the source of cellulosic fibres and preparation method [[3]].Other nanofillers, very recently discovered with large potential in water treatment applications are MXenes. MXenes are a new class of 2D metal carbides and carbonitrides, which are both conductive as well as hydrophilic [[4]]. MXenes have general formula Mn+1Xn, derived from MAX phases, where M is an early transition metal, A is an A-group element, mostly IIIA and IVA, or groups 13 and 14, and X is either carbon and/or nitrogen, by chemical etching in HF or NH4HF2 solutions, where n = 1, 2 or 3. The unique structure of MXenes offers combination of excellent mechanical properties, hydrophilic surface, transparency and metallic conductivity. Herein, we used electrospinning to prepared novel membranes based on copolyamide 6,10 reinforced by nanocellulose prepared from Qatari date palm waste and MXene 2D nanofillers which dramatically improved mechanical performance and separation efficiency of the membranes compared to neat copolyamide membranes. Prepared membranes were able to separate oil (vegetable and diesel) from water with efficiency over 96 % regarding of membrane composition and separation conditions. Additionally membranes exhibited good lifetime with maintaining high efficiency of separation. Acknowledgements This work was made possible by NPRP grant No.: 7-1724-3–438 from the Qatar National Research Fund (A Member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. References [[1]] A.D.N. Nemerow, Industrial and Hazardous Waste Treatment, Van Nostrand Reinhold, New York, 1991. [[2]] G.-R. Xu, J.-N. Wang, C.-J. Li, Strategies for improving the performance of the polyamide thin film composite (PA-TFC) reverse osmosis (RO) membranes: Surface modifications and nanoparticles incorporations, Desalination 328 (2013) 83–100. [[3]] A.C.W. Leung, S. Hrapovic, E. Lam, Y. Liu, K.B Male, K.A. Mahmoud. Characteristics and Properties of Carboxylated Cellulose Nanocrystals Prepared from a Novel One-Step Procedure. Small 7(3) (2011) 302-5. [[4]] M. Naguib, M.W. Barsoum, Y. Gogotsi. 25th Anniversary Article: MXenes: A New Family of Two-Dimensional Materials. Advance Materials 26(7) (2014) 992 - 1005.Acknowledgements This work was made possible by NPRP grant No.: 7-1724-3–438 from the Qatar National Research Fund (A Member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. References

Hydroxyethyl cellulose and cobalt chloride are used as precursor materials for the synthesis of cobalt oxide (Co3O4) nanoparticles. A composite system from polymer and metal chloride is prepared via casting technique. The thermal decomposition of the composite is studied using thermogravimetric technique. Calcination of the composite system at 350°C resulted in the formation of Co3O4 nanoparticles. X-ray diffraction analysis reveals the presence of crystalline Co3O4 with an average particle size of around 15 nm. The bonding nature and morphology of nanosized Co3O4 are examined using transmission electron microscopy and infrared spectroscopy. The Tauc's plot indicates the energy band gap for direct allowed transition as 3.2 eV and 1.4 eV. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

We present a novel instrumentation scheme for measuring the two-dimensional distribution of spectral reflectance based on the spectral imaging technique. It takes digital spectral images of a test sample using a LED-based monochromatic integrating sphere source and a monochrome CCD camera. We developed a calibration algorithm to assign the digital counts of the images to the reflectance values at each wavelength. The measurement uncertainty is evaluated to be less than 1.5% (k = 2) for high-reflectance samples (with reflectance ≥0.4) and less than 3% (k = 2) for low-reflectance samples (with reflectance

In this study, poly(vinyl alcohol) (PVA) films doped with thorium nitrate hydrate [Th(NO3)4] have been prepared using casting technique. The optical absorption spectra were recorded at room temperature in the wavelength range 200–800 nm. From the absorption edge studies, the values of the Urbach energy (Eu) have been evaluated. These energy values vary slightly with composition, indicating that the model based on electronic transitions between localized states is not preferable. Optical parameters such as refractive index and complex dielectric constant have been determined. The dispersion of the refractive index is discussed in terms of the single-oscillator Wemple-DiDomenico model. Color properties of the prepared samples were discussed in the framework of CIE L*u*v* color space. POLYM. COMPOS., 35:1786–1791, 2014. © 2013 Society of Plastics Engineers

In this work, Judd–Ofelt analysis is applied to Er nanoparticles doped cadmium-phosphate glasses in order to evaluate their potential in glass laser systems. The phenomenological Judd–Ofelt parameters Ω(2), Ω(4) and Ω(6) are determined for one glass system and the quality factor is compared with equivalent parameters for several other glass hosts. The spontaneous emission probabilities, lifetimes, branching ratios of Er3 + transitions from the excited – state J manifolds to the lower – lying J' manifolds are determined. The glass fluorescence emission (611, 628, 638, 662.5, 716.4 nm) lines are observed. The above lines are assigned to 4G11/2 → 4I11/2, 4F3/2 → 4I13/2, 4F5/2 → 4I13/2, 4F9/2 → 4I15/2, and 4F7/2 → 4I13/2 transitions respectively. Their emission cross sections are calculated. The transition 4F9/2 → 4I15/2 in the red spectral region has large radiative time, branching ratio, and stimulated emission cross section which indicates the suitability of glass system to be used in laser and electroluminescence applications.

Carboxymethyl cellulose (CMC) films doped with nickel chloride hexahydrate have been prepared by casting technique. The phase transitions and thermal stability of the prepared samples were investigated by differential scanning calorimetry and thermogravim- etry. The optical absorption was recorded at room temperature in the wavelength range of 190-2500 nm. From the absorption edge studies, the values of the Urbach energy (Ee) were found to be 0.58 eV in case of the pure polymer; however, the Urbach energy values were found to be in the range of 0.64-1.0 eV under additional different percentages of nickel chloride. These energy values indicate that the model based on random fluctuations of the internal fields associated with structure disorder is preferable and transitions are made between band tails. Refractive index, complex dielectric constants have also been determined. Color properties of the prepared samples are discussed in the frame work of CIE L*u*v* color space. V C 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 127: 4334-4339, 2013

Natural rubber (NR)-barium ferrite (BaF) composites (RFCs) have been prepared. Structural features of the composites were characterized by Infrared spectroscopy and scanning electron microscope (SEM). Differential scanning calorimetry (DSC) analysis showed that there is small variation of glass transition temperature (≈ –1℃). The activation energy of glass transition was calculated by Kissinger method and has values between (53-110 kJ/mol). Thermodynamic parameters such as activated entropy, enthalpy and Gibbs free energy were calculated for glass transition also. Thermogravimetric analysis TG and its derivative DTG showed one stage thermal decomposition between 300℃-400℃ with weight loss between (19.47%-52.13%). Increasing barium ferrite loading will increase the thermal stability of natural rubber. The kinetic parameters such as activation energy, entropy, enthalpy and Gibbs free energy for composites in the decomposition region were calculated and analyzed using Coats-Redfern technique.

Films with different compositions of polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) blends have been prepared using the casting method. Differential scanning calorimetery (DSC), thermogravimetric analysis (TGA) and dielectric spectroscopy of all compositions have been investigated. It was found that PVA and CMC are compatible in the studied range of composition. With increasing CMC content, the thermal stability of PVA increases. Based on DSC and TGA data, the activation energies of all the investigated samples were calculated. The absorption edge ( E a ) was also determined from Ultraviolet–visible (UV–vis) spectra. Dielectric permittivity, loss tangent and ac conductivity of all samples were studied as functions of temperature and frequency. The results show that the dielectric dispersion consists of both dipolar and interfacial polarization. The frequency dependence of the ac conductivity indicates that the correlated barrier hopping (CBH) is the most suitable mechanism for conduction. The polaron binding energy ( U M ) was determined. Results of the present system are compared with those of similar materials.

2,7-di-tert-butylpyrene was oxidized to 2,7-di-tert-butylpyrene-4,5,9,10-tetraone. The latter through condensation reactions with vicinal diamine such as 4,5-diaminophthalonitrile produced heterocyclic monomer, 2,7-di-tert-butyl pyrene[4,5][9,10]bisquinoxaline-6,7-dinitrile, which was cyclo-tetramerized to the corresponding tetra[2,3-(1,4-diaza-6,6-di-tert-butylphenanthreno)[4,5]phthalocyanine]-based network polymer (2H-Pc), and tetra [2,3-(1,4-diaza-6,6-di-tert-butylphenanthreno)[4,5]phthalo-cyaninato metal II-based network polymers (M-Pc, M= Co, Ni, Zn, or Cu). Elemental analytical results, IR and NMR spectral data of the new prepared molecules are consistent with their assigned formulations. Molecular masses and metal contents of the synthesized polymers proved to be of high molecular masses which confirm the efficiency of tetramerization polymerization and complexation reactions. The dielectric constant (e′) and dielectric loss tangent (tan δ) were studied as a function of temperature and frequency. The detailed analysis of the results showed that the dielectric dispersion consists of both dipolar and interfacial polarization. Measurements of ac conductivity as a function of frequency at different temperatures revealed that the nonoverlapping small polaron tunneling is the most suitable mechanism for ac conduction behavior. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Glasses with compositions xBi 2 O 3 –(75–x) B 2 O 3 –25Li 2 O with, x = 0, 5, 20, 25,30,35,40 mol % have been prepared using the normal melt quenching technique. The dielectric constant (έ) dielectric loss tangent tan δ , electric modulus behaviour was studied as a function of temperature in the frequency range 0.1–100 kHz. The detailed analysis of the results showed that the dielectric dispersion consists of both dipolar and interfacial polarization. Also the activation energy of the dielectric relaxation process from the electric modulus measurements was calcaulated. Measurements of the ac conductivity as a function of frequency at different temperatures indicated that the correlated barrier hopping (CBH) model is the most suitable mechanism for the ac conduction behaviour. The ac parameters, such as hopping distance ( R , R min ), polaron binding energy ( U M ) and Columbic barrier height ( U h ) were calculated.

A spectroscopic investigation is performed on Nd 3+ doped cadmium-phosphate glasses. The Judd–Ofelt analysis is applied to the glass system in order to evaluate their potential as both glass laser and amplifier materials. The phenomenological Judd–Ofelt parameters Ω (2) , Ω (4) , and Ω (6) are determined, their values are 4.80×10 −20 , 6.18×10 −20 , and 7.14×10 −20 cm −2 , respectively. The quality factor for glass system is 0.86. Predicted radiative decay rates and branching ratios of transitions from Nd 3+ 4 F 3/2 state to the 4 I J manifolds are determined and analyzed. The calculated lifetime of the 4 F 3/2 metastable state of Nd 3+ is 31 μs. The results showed that 4 F 3/2 to 4 I 11/2 transition, with fluorescence at 1056 nm, has the most potential for laser application. Photoluminescence up-conversion under excitation at 488 nm laser light exhibits three emission bands of Nd 3+ ions at 541 (green), 601 (orange), and 677 nm (red). These emission bands are assigned to 4 G 7/2 → 4 I 9/2 , 4 G 7/2 → 4 I 11/2 , and 4 G 7/2 → 4 I 13/2 transitions, respectively. Analysis of luminescence spectra enhances the use of glass system in optical displays, lasers, and optical memory devices.

A method linking pulse energy scale to continuous wave (CW) power scale is described. The connection between CW power and pulse energy is established by generating pulses from CW beam, and correlating the CW signal measured by reference optical power meter and pulsed-signal measured by calorimeter. In this connection CW laser source from which pulses are generated is Nd:YAG laser and the lengths of pulses adjusted are at the order of milliseconds. The realized energy scale is transferred from calorimeter to laser energy meters through using pulsed Nd: YAG laser having one fundamental (at 1064 nm) and two harmonics (at 532 nm and at 365 nm) with nano-second level pulse length.

Glasses with compositions xBi2O3(75−x)B2O325Li2O3 for 0≤x≤40 mol% have been prepared using the normal melt-quenching technique. The optical absorption and reflection spectra were recorded at room temperature in the wavelength range 190–1100 nm. From the absorption edge studies, the values of the optical band gap (Eopt) and Urbach energy (ΔE) have been evaluated. Optical parameters such as refractive index and complex dielectric constant have been determined. The dispersion of the refractive index is discussed in terms of the single-oscillator Wemple–DiDomenico model. Color parameters and color difference data L*, U*, V*, C*, hue, W, Ye, ΔL*, ΔU*, ΔV*, ΔC*, and ΔE have been calculated.

Cast thin films of polyvinyl alcohol/glycogen blends of different compositions have been prepared and subjected to the electrical measurements of both current–time and current–voltage characteristics as well as d.c. conductivity as a function of temperature. The conduction mechanisms operative in the films at different temperature and voltage ranges are estimated from the behavior of log I versus V1/2 plots. For individual polymers, the conduction mechanism appears to be essentially a Poole–Frenkel type. On blending, at lower temperature the charge conduction is through the Schottky emission while at higher temperature the charge conduction mechanism is Poole–Frenkel. In addition, the deviation of the plots at lower voltages indicates the existence of space charge contribution in conduction mechanism. The obtained results made it possible to determine several conduction parameters including activation energy, carrier mobility, and carrier concentration. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers

The transient currents, I–V characteristics and dc electrical conductivity of 70/30 (wt/wt.%) polyvinyl alcohol (PVA)/glycogen undoped and doped with eosin films have been studied under different conditions before and after irradiation by γ-doses in the range 5–100 kGy. The conduction mechanisms operative in the films at different temperature and γ-irradiation ranges are estimated from the behaviour of Log I versus V1/2 plots. The results show that both temperature and γ-irradiation affects the type of electronic transport mechanism for undoped blend sample. On doping with eosin, there is only considerable influence on the type of conduction with varying temperature but γ-doses have no significant effect. The dc conductivity for blend sample doped with eosin is found to increase by 1–2 orders of magnitude compared to the undoped sample at both different temperatures and γ-doses. The values of mobility and charge carrier concentration for all samples under investigation were found to vary from (0.26–2.22) × 10− 4m2V− 1 s− 1 and (0.52–76.20) × 1024 m− 3 respectively.

The dielectric relaxation spectra of various poly(vinyl alcohol) (PVA)/glycogen blends and irradiated blend samples with 70 wt % PVA content that were undoped and doped with eosin were measured in extended temperature (30–160°C) and frequency (1 kHz to 1 MHz) ranges. Dielectric relaxation spectroscopy separates different molecular groups of a repeating unit of a polymer with respect to the rate of its orientation dynamics. In the high-temperature range (>100°C), the σ relaxation, which is associated with the hopping motion of ions in the disordered structure of the biopolymeric material, can be measured. The electric dipole moment and the activation energy of the glass-transition temperature relaxation process were calculated. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Differential scanning calorimetry (DSC) was used to identify the phase transitions of polyvinyl alcohol (PVA) doped with europium chloride (EuCl 3 ) and terbium chloride (TbCl 3 ). The dielectric constant and the loss tangent behavior of the investigated samples were studied as a function of temperature in the frequency range 1–100 kHz. The detailed analysis of the results showed that dielectric dispersion consists of both dipolar and interfacial polarization. The temperature coefficient of permittivity (TCP) and the electrical dipole moment ( μ ) were calculated. Also, the activation energy for the glass relaxation process from the dielectric loss tangent measurements was calculated. Measurements of the ac conductivity as a function of frequency at different temperatures indicated that the correlated barrier hopping (CBH) model is the most suitable mechanism for the ac conduction behavior. The ac parameters, such as hopping distance ( R , R min ), polaron binding energy ( U M ) and Coulombic barrier height ( U h ) were calculated.

Differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), UV/visible spectra and colour detection of pristine and γ-irradiated undoped and eosin-doped 70/30 (wt/wt%) PVA/glycogen has been measured. The kinetic parameters such as the activation energy, entropy, enthalpy and free energy for all investigated samples were determined using Coats–Redfern relation. The shift of T g position towards lower temperatures with increasing γ-doses reflect that the degradation process is the predominant one. The values of absorbance and optical parameters in UV/visible range for γ-irradiated blend sample doped with eosin showed no significant variation with increasing γ-doses. This reflects that the addition of eosin to 70/30 (wt/wt%) PVA/glycogen makes it more resistant to γ-radiolysis. The calculated colour parameters such as L ∗ , U ∗ , V ∗ , C ∗ , hue and Y e were found to be dependent on addition of eosin and γ-irradiation.

We present an instrumentation solution for measurement of normalized spectral responsivity of digital imaging sensors and cameras. The instrument consists of multiple light-emitting diodes (LEDs), a single-grating monochromator, and a small-size integrating sphere. Wavelength tuning is achieved by a proper selection of LED in accordance with the monochromator setting in a range from 380 to 900 nm. High spectral purity with a bandwidth of 5 nm is realized without using double gratings and order-sorting filters. Experimental characteristics and calibration of the instrument are described with the related error and uncertainty sources. The performance is demonstrated by measuring a monochrome charge-coupled device and a trichromatic complementary metal-oxide-semiconductor device. The measurement uncertainty is evaluated to be less than 1% (k=2) except several wavelengths with low LED power.

13th International Conference on Greenhouse Gas Control Technologies, GHGT-13, 14-18 November 2016, Lausanne, Switzerland, Optical image analysis (OIA) allows a quantitative characterization of pore space measured through thin sections. Together with petrographic studies, by using optical microscopy (OpM), OIA could provide a reproducible pore characterization of sedimentary rocks in applications related to the geological storage of CO2. This research is focused on the application of the OIA technique to measure porosity on thin section samples of sandstones from Spain before and after CO2 injection to supercritical (SC) conditions in autoclave (P ≈ 7.5 MPa and T ≈ 35 °C). The aim of this article is to show preliminary measures by OIA using images acquired with high-resolution scanner (HRS). Mineral images were acquired from thin sections before and after SC-CO2 injection. The optical measures of porosity on the thin sections of sandstones showed an effective pore segmentation considering different images in cross-polarized light conditions (90°/0°; 120°/30°) and plane-polarized light conditions (90°/-) of the same petrographic scene. Mineralogical studies by OpM and OIA-HRS have allowed an exhaustive characterization of the samples studied and a preliminary approximation of the CO2-rock interactions. This study shows a fast, effective and reproducible methodology that allowed the researchers to obtain qualitative information about changes in the pore network (optical porosity) distribution on the thin section that could be applied to similar experimental injection tests., Unidad de Oviedo, Instituto Geológico y Minero de España, España, Departamento de Geología, Universidad de Oviedo, España, Indiana Geological Survey, Estados Unidos