Current Electrical Conductivity Research Articles

Advancing X‐Band Electromagnetic Interference Shielding: Single‐Layer Thin Films of Fe3O4‐MWCNT (1:2)‐PVDF Meta‐Nanocomposite Fabricated by Low‐Cost Drop‐Casting Process

This study, investigate of ternary thermoplastic fluoropolymer blend nanocomposite (NC) system for improved microwave (MW) shielding, consisting of polyvinyl dimethylamine fluoride (PVDF) and Fe3O4‐multiwalled carbon nanotube (MWCNT) (1:2) NC. Using a hydrothermal process, complex hierarchical nanostructures (NSs) of Fe3O4‐MWCNT (1:2) NC are produced. These NSs are then integrated using a drop‐casting technique into PVDF matrices with different wt% (20, 40, and 60 wt%) and thicknesses (20, 50, and 80 μm). The single‐layer thin films (SLFs) with the Fe3O4‐MWCNT (1:2)‐PVDF matrix are successfully produced as a consequence of this approach. The presence of FeOC bonding from X‐ray photoelectron spectroscopy (XPS) analysis confirms chemical interaction, while scanning electron microscopy (SEM–Energy dispersive spectroscopy EDX) imaging analysis for material homogeneity. Moreover, the SLFs of Fe3O4‐MWCNT (1:2)‐PVDF (20, 40, and 60 wt% for 80 μm thickness) are newly discovered meta‐nanocomposites (MNCs) properties, which are evidenced by negativeMW real complex permittivity (−274.4, −271.2, and −136.4), superior attenuation constant (12862.73, 16265.18, and 12256.34), and higher alternating current (AC)electrical conductivities (1020.8, 1174.6, and 727.7 S m−1). The synergistic impact of higher attenuation and AC conductivity of MNCs results in an increased average MW shielding effectiveness of ≈33.28 dB for Fe3O4‐MWCNT (1:2)‐PVDF 20 wt% MNCs (≈80 μm).

Assessment of the Influence of Fabric Structure on Their Electro-Conductive Properties.

Electro-conductive fabrics are key materials for designing and developing wearable smart textiles. The properties of textile materials depend on the production method, the technique which leads to high conductivity, and the structure. The aim of the research work was to determine the factors affecting the electrical conductivity of woven fabrics and elucidate the mechanism of electric current conduction through this complex, aperiodic textile material. The chemical composition of the material surface was identified using scanning electron microscopy energy dispersion X-ray spectroscopy. The van der Pauw method was employed for multidirectional resistance measurements. The coefficient was determined for the assessment of the electrical anisotropy of woven fabrics. X-ray micro-computed tomography was used for 3D woven structure geometry analysis. The anisotropy coefficient enabled the classification of electro-conductive fabrics in terms of isotropic or anisotropic materials. It was found that the increase in weft density results in an increase in sample anisotropy. The rise in thread width can lead to smaller electrical in-plane anisotropy. The threads are unevenly distributed in woven fabric, and their widths are not constant, which is reflected in the anisotropy coefficient values depending on the electrode arrangement. The smaller the fabric area covered by four electrodes, the fewer factors leading to structure aperiodicity.

Review of the second charged-particle transport coefficient code comparison workshop

We report the results of the second charged-particle transport coefficient code comparison workshop, which was held in Livermore, California on 24–27 July 2023. This workshop gathered theoretical, computational, and experimental scientists to assess the state of computational and experimental techniques for understanding charged-particle transport coefficients relevant to high-energy-density plasma science. Data for electronic and ionic transport coefficients, namely, the direct current electrical conductivity, electron thermal conductivity, ion shear viscosity, and ion thermal conductivity were computed and compared for multiple plasma conditions. Additional comparisons were carried out for electron–ion properties such as the electron–ion equilibration time and alpha particle stopping power. Overall, 39 participants submitted calculated results from 18 independent approaches, spanning methods from parameterized semi-empirical models to time-dependent density functional theory. In the cases studied here, we find significant differences—several orders of magnitude—between approaches, particularly at lower temperatures, and smaller differences—roughly a factor of five—among first-principles models. We investigate the origins of these differences through comparisons of underlying predictions of ionic and electronic structure. The results of this workshop help to identify plasma conditions where computationally inexpensive approaches are accurate, where computationally expensive models are required, and where experimental measurements will have high impact.

A computational method for calculating the electrical and thermal conductivity of random composites

In the present work, for the first time, the electrical–thermal conductivity of a composite random material is correlated with the number of conductive paths, the mean path length, and the mean effective path width measured in a representative surface element (RSE) by Monte Carlo sampling. This work is organized in two parts. The theoretical calculation takes place in the first part for the correlation of conductive paths by adopting three approaches (incremental with respect to accuracy and complexity) based on: (i) one-component straight paths; (ii) one-component non-straight paths; (iii) multi-component non-straight paths. In the second part, a novel numerical methodology for the calculation of the conductance of the RSE through the conductive paths, mean path length and the mean effective path is developed for the general model of multi-component non-straight line paths based on Ohm’s law. In addition, a methodology that reduces the calculated conductivity from the microscale to the macroscale is proposed, that takes into account the probability of percolation for finite sizes and the average value of the conductivity from the samples in which percolation occurs. After the necessary consistency steps and verification of the method and its implementation on random binary material systems, it is further applied to solve synthetic continuous percolation problems at the microscale and macroscale. The results and the accuracy of the calculations are in close agreement with existing models. The electrical Direct Current (DC) and thermal conductivity follow the same scaling relation and the proposed methodology can be applied at the same stage without additional cost. In a random binary medium the simulations showed that a scaling law of conductivity is followed by an exponent value close to 1.3. In addition, the number of conductive paths, the average length of the paths, and the effective width follow scaling laws with exponents 1.44±0.01 , −0.25±0.01 and −0.39±0.01, respectively.

Micro contact modeling of electrical current conduction behavior between carbon fiber yarns

Electrical contact conduction between carbon fiber yarns is one of the important current conduction paths inside carbon fiber composites and is easily affected with fabric reinforcement structure and manufacturing process. Here we proposed a micro contact model to predict the contact resistance and to reveal the current conduction behavior between carbon fiber yarns. The model takes into account tunneling effect and yarn geometric structure. The fiber contact probability between yarns was determined based on the statistical characteristic of the fiber height on the yarn surface. The relationship between the yarn contact resistance in plain weave fabric and out-of-plane force was measured and the experimental results agree well with the model. We found that the current conduction between yarns depends on contact conduction between fibers and the contribution of tunneling conduction is negligible. The proposed micro contact model provides insight into the current conduction behavior between carbon fiber yarns and is meaningful for the electrical conductivity design of carbon fiber composites.

Dielectric and viscoelastic properties of 3D-printed biobased materials

This study aimed to develop new biobased materials containing plasticized cellulose acetate (CA) by Fused Filament Fabrication (FFF). We investigated the influence of CA on the viscoelastic/dielectric properties and the influence of 3D printing on the dielectric properties of the polymer blends. A microstructural analysis showed that the blends had a strong heterogeneous morphology, as the two phases formed a fibrillar and lamellar structure. CA strongly increased the blend viscosity at 175 °C, multiplying by 100 times the complex viscosity between neat PLA and the blend containing 40% of CA by weight (CA-40). The addition of CA to the blends increased the dielectric constant (ε') and dielectric loss (ε''), as well as the alternative current electrical conductivity (σAC). The dielectric constant of CA (ε'CA) was proportional to its percentage in the blend, showing a behavior analogous to a rule of mixture. Moreover, the activation energy of the electrical conductivity (σDC) measured at T > 124 °C decreased with increasing CA content and was associated with the enhancement of the ionic conductivity provided by the CA and its plasticizer. A decrease in the α-relaxation temperature and the associated activation energy of the PLA was also linked to the presence of the CA plasticizer. Finally, 3D printing greatly decreased both ε', ε'' and σAC due to the internal voids induced by the 3D printing process. The porosity was measured at 12% for neat PLA and between 20% and 25% for the blends. These results showed the advantage provided by FFF technology in the production of PLA:CA blends with controlled dielectric properties, thereby favoring the use of these new materials in key dielectric areas.

Insights into processes and consequent metal(loid) behavior in dredged estuarine sediments upon electrokinetic treatment

The use and reuse of natural and waste materials after treatment has become increasingly crucial as a means of achieving sustainable and environmentally-friendly solutions, and is part of a broader trend towards embracing circular economy principles. This study aims to understand the behavior of different elements (metal(loid)s and non-metals) and minerals during and after electrokinetic remediation (EKR) and to develop an effective approach to monitor its progress and overcome unwanted occurrences. In this regard, estuarine sediments, collected from Tancarville (Seine River estuary, France), were electrokinetically treated using a 64 L laboratory reactor; treatment was done 8 h per day for 21 days. The physico-chemical properties (pH, electric conductivity, and oxido-reduction potential) and current were monitored during treatment. The spatial evolution of the physico-chemical, physical (grain size distribution), mineral (mainly carbonates), organic, and elemental (As, Ca, Cl, Mg, Na, Pb, Sr, Zn, and Zr) characteristics was studied to assess the treatment efficiency. The results showed that the acidic conditions in the anodic sediments caused the dissolution of carbonates (calcite, dolomite, and aragonite), resulting in a considerable reduction in As, Zn, and Pb. Additionally, Cl as well as electric conductivity were significantly reduced from most sediments, which is essential in agricultural practices. Furthermore, materials had precipitated and settled in the anolyte and catholyte chambers, which acted as sorbents for elements that were released from the sediments (mainly Zn and As). Finally, three distinct phases occurred during treatment and were mainly linked to the current intensity and electric conductivity on the one hand, and the dissolution of carbonates and metal(loid) release on the other. This approach can be used to treat sediments and other media to improve the overall efficiency of remediation processes and create an end product with desired characteristics.

Enhancement of electrical conductivity of biopolymer by sulfur nanoparticle dispersion technique

AbstractPresent work reports the investigation of the effect of different percentages of nanosized elemental sulfur particle grown in a biopolymer matrix. Sulfur is known for treatment against bacterial infections as an antimicrobial agent from ages as elemental sulfur and sulfur‐rich compounds interact with biological systems. In‐situ growth of sulfur nanoparticles is processed by the passage of environment friendly hydrogen sulfide gas in hydrated solution of gum acacia biopolymer. Gum acacia is ion conducting, plant derived natural polymer. In this work, structural and morphological studies are examined by x‐ray diffraction and scanning electron microscopy. It is found that with increasing concentration of sulfur nanoparticles the spheroidal shaped nanostructures grow in size and approaches the micron realm. Electrical characterization of the nanostructure synthesized biopolymer is observed by varying frequency over a broad‐spectrum range. Direct current electrical conductivity is found to be enhanced by 40 times higher over pure specimen.

Quantitative Nondestructive Evaluation of Cold Spray Manufactured Aluminum Alloy 6061 and Copper Samples

Cold spray (CS) is a solid-state process for depositing thick layers of material via the successive high-velocity impact of powder particles onto a solid surface, which leads to high rates of deformation, interparticle bonding, and coating build-up. Although CS is finding commercial utilization in non-load-bearing repair and coating applications, clear nondestructive characterization procedures are necessary to realize its potential in load-bearing structural applications. In this study, the viability of electrical conductivity and through thickness ultrasound wave velocity measurement methods was studied to serve as a means for nondestructive quantitative measurement for quality control in CS and potentially other additive manufacturing (AM) methods. Eddy current, ultrasound, porosity, hardness, and uniaxial tensile strength tests were conducted on CS deposited layers of aluminum alloy 6061 and copper on aluminum alloy 6061 and commercially pure copper substrates, respectively. CS gas dynamic parameters were intentionally and systematically varied to result in corresponding discrete differences in mechanical properties of deposits. Ultrasound measurements of longitudinal wave velocity and eddy current electrical conductivity measurements showed good correlation with process conditions, microstructural characterization results, and destructive mechanical tests (hardness, tensile). The results of this work show that ultrasound wave velocity and electrical conductivity correlate well with increased particle impact velocity in CS deposited aluminum and copper blocks, which evidently show an incremental decrease in porosity, increase in hardness, and increase in tensile strength. The outlined ultrasound and eddy current nondestructive testing methods present effective means for quantitative assessment of cold spray deposited structures while intact with the substrate.

Ag-doped NiS nanocubes: Tailoring properties for optimal antibacterial performance

This study explores the synthesis of silver-doped nickel sulfide nano-cubes (Ni1-xAgxS: x= 0.00, 0.04, and 0.08) through a cost-effective hydrothermal process. X-ray diffraction analysis assured the presence of hexagonal NiS nanoparticles with fine crystallinity, with an estimated crystallite size of Ag-doped NiS ranges from 21.19 to 15.69 nm. A reduction in crystallite size was observed while including Ag ions along with enhancement in lattice constants for ‘a’ and ‘b’ from 3.416 Å to 3.424 Å and ‘c’ from 5.280 to 5.286 Å. The scanning electron microscopic images displayed cubic shaped agglomerated particles, that seemed quite suitable for antibacterial activity. The materials exhibit semiconducting behavior, as evidenced by increased direct current electrical conductivity with the rise in temperature. With increased silver content, the direct current electrical conductivity rises, and activation energy decreases from 0.246 to 0.213 eV. Dielectric characteristics, including dielectric constant, dielectric loss, and AC electrical conductivity, show a positive correlation with temperature, and all the aforementioned values elevates with systematic variation in Ag doping. The Agar well-diffusion method evaluates the antibacterial activity of un-doped and Ag-doped NiS nano-cubes against various pathogens, such as Gram-positive bacteria (M. luteus and S. aureus) and Gram-negative bacteria (E. coli and S. enterica), and significant inhibitory zones against all tested microbes, confirming the potential antibacterial efficacy. The Ag-doped NiS exhibited enhanced antibacterial efficiency. This research highlights Ag-doped NiS nano-cubes attributed with multifaceted functionalities, making them promising candidates for particular usage such as targeted drug delivery systems, antibacterial powder, wastewater treatment and pharmaceutical applications.

Compensation of the material temperature influence on specific electrical conductivity during eddy current structurescopy

The importance of eddy current measurements of specific electrical conductivity (SEC) of materials in non-destructive testing for solving problems of structuroscopy is discussed. In particular, their significant role is shown for estimation of the degree of changes in the mechanical characteristics of structural materials due to degradation processes in their structure. The influence of the temperature of metallic structural materials on the results of eddy current measuring of SEC has been studied. An analytical expression for the output signal of the SEC measuring channel of an electrical eddy current conductivity meter for real temperature of material is obtained. It depends on the value of the material SEC at a nominal temperature value (usually 20 C), temperature coefficient of electrical resistance of the material and the deviation of the material real temperature from the nominal value. It is shown that in order to tune out this effect and bring the measurement results to the nominal temperature, it is necessary to use eddy current meters with an additional channel for measuring the material temperature in the testing zone. The output signal of this channel is used to correct the SEC measurement results. This is carried out by multiplying the output signal of the SEC measurement channel and some auxiliary signal. This auxiliary signal is generated from the output signal of the temperature measurement channel by it scaling and summation with the signal of the direct current voltage reference source. A functional diagram of the eddy current SEC meter with temperature correction is proposed. A detailed description of it operation is given. In the absence of preliminary information about the grade of material and the value of its temperature coefficient of electrical resistance, is proposed to suppress the influence of temperature by test changes in the temperature of the material in the testing zone. At the same time, it is necessary to adjust the gain of the scale converter. This is done until the readings of the eddy current SEC meter do not depend on the material temperature in the testing zone.

Determination of Porosity and Formation Resistivity Factor for a Leachate-Saturated Waste

The factors of porosity and formation resistivity have a strong influence on the process of electric current conduction through saturated porous media. In this study, laboratory experiments were carried out to calculate the resistivity formation factor from electrical resistivity measurements for leachate-saturated waste in samples collected from the Bakung landfill in Bandar Lampung. The formation resistivity factor is calculated using the Archie equation by calculating the representative value of the intercept (a) and the cementation factor (m) as used by Archie in the derivative relationship between the formation resistivity factor (F) and porosity (ϕ). This study investigates the impact of leachate spatial distribution on electrical resistivity. Electrical resistivity and porosity were measured in 27 soil samples. Each soil sample was subjected to three treatments: without leachate injection, unsaturated leachate injection (physical modelling), and fully saturated leachate injection (physical modelling). The results show that resistivity formation factors and porosity have a relationship. The values of ‘a’ and ‘m’ were determined at the study site based on the relationship between formation factors and porosity. The findings should create new insights into applied geophysics.

ZnS-integrated polypyrrole and emeraldine polyaniline composites for enhance photophysical and electrochemical performance for an active layer in an optoelectronic device

In this article, the work has been planned with the primary goal of investigating the influence of ZnS on the structural, optical, thermal, and electrochemical characteristics of polymers (polypyrrole and polyaniline). Polypyrrole-ZnS (PPZ), Polyaniline-ZnS (PAZ) was synthesized by chemical oxidative in-situ polymerization method. The formation of the phase, crystallinity, and cell parameter of the synthesized samples were examined through X-ray diffraction. FTIR and Raman spectroscopy was used to determine the desired functional group and state of the molecules present in the synthesized compounds. The materials' in-depth surface morphology was investigated using TEM and FESEM. EDX and XPS analyses were performed to determine the elemental, chemical, and electronic states of the atoms within the materials. The PPZ and PAZ optical band gaps were calculated to be 2.19 eV and 1.84 eV, respectively, with refractive indexes of 1.96 and 2.36, indicating strong optical conductivity in the visible region. The PL spectra indicated a significant rate of electron-hole recombination in the blue region. TGA-DSC-DTA research revealed that polymeric composites for emissive layer materials have high thermal stability. Polymeric composites achieved excellent current density and electrical conductivity. The above findings showed that PPZ and PAZ are suitable materials for emissive layers in PLEDs.

Effect of electron irradiation on alternating current electrical properties of gelatin – cadmium sulfide nano‐composite films

AbstractGelatin was doped with 1 %, 3 %, 5 % and 10 % cadmium sulfide nanoparticles in weight concentrations forming the gelatin‐cadmium sulfide nanocomposites and irradiated by various electron beam doses equals 50 kGy, 75 kGy, 100 kGy, and 150 kGy using 3 MeV – 3 mA electron accelerator. The applied alternating current electrical field frequency ranging from 70 Hz to 5 MHz is what caused the fluctuation in dielectric properties and alternating current electrical conductivity of these nanocomposites. The results showed that the films of 1 %, 3 %, 5 %, and 10 % for blank (nanocomposite film without electron beam irradiation) nanocomposites had the highest dielectric parameters (έ, ϵ′′, tan δ) at 0.5 kHz with values of (0.696, 0.0233, 0.034), (0.533, 0.0114, 0.0215), (0.402, 0.001196, 0.003), and (0.459, 0.00418, 0.0091), respectively. However, the lowest dielectric parameters were (0.645, 0.00618, 0.0066), (0.523, 0.00165, 0.0215), (0.417, 0.00035, 0.0008), and (0.455, 0.00066, 0.0015) at 5 MHz, respectively. The highest conductivity values for blank nanocomposites of 1 %, 3 %, 5 %, and 10 % were 1.79×10−4 S/m, 1.45×10−4 S/m, 1.16×10−4 S/m, 1.27×10−4 S/m at 5 MHz, and the lowest values were 1.92×10−8 S/m, 1.49×10−8 S/m, 1.13×10−8 S/m, 1.26×10−8 S/m at 0.5 kHz, respectively. For irradiated nanocomposites at 5 MHz, the dielectric constant order for 1 % was 100 kGy, 150 kGy, 50 kGy, and 75 kGy with values 0.63, 0.537, 0.532, and 0.523, respectively. For 10 % weight concentration, the order was 50 kGy, 100 kGy, 150 kGy, and 75 kGy with values 0.515, 0.477, 0.47, and 0.437, respectively. Otherwise the dielectric constant order for 3 % and 5 % was 100 kGy, 75 kGy, 150 kGy, and 50 kGy. The highest dielectric properties and conductivity values for blank and irradiated nanocomposites were observed at 100 kGy for 1 %, 3 %, and 5 %.

Fast and Uncooled Semiconducting Ca-Doped Y-Ba-Cu-O Thin Film-Based Thermal Sensors for Infrared.

YBa2Cu3O6+x (YBCO) cuprates are semiconductive when oxygen depleted (x < 0.5). They can be used for uncooled thermal detection in the near-infrared: (i) low temperature deposition on silicon substrates, leading to an amorphous phase (a-YBCO); (ii) pyroelectric properties exploited in thermal detectors offering both low noise and fast response above 1 MHz. However, a-YBCO films exhibit a small direct current (DC) electrical conductivity, with strong non-linearity of current-voltage plots. Calcium doping is well known for improving the transport properties of oxygen-rich YBCO films (x > 0.7). In this paper, we consider the performances of pyroelectric detectors made from calcium-doped (10 at. %) and undoped a-YBCO films. First, the surface microstructure, composition, and DC electrical properties of a-Y0.9Ca0.1Ba2Cu3O6+x films were investigated; then devices were tested at 850 nm wavelength and results were analyzed with an analytical model. A lower DC conductivity was measured for the calcium-doped material, which exhibited a slightly rougher surface, with copper-rich precipitates. The calcium-doped device exhibited a higher specific detectivity (D*=7.5×107 cm·Hz/W at 100 kHz) than the undoped device. Moreover, a shorter thermal time constant (<8 ns) was inferred as compared to the undoped device and commercially available pyroelectric sensors, thus paving the way to significant improvements for fast infrared imaging applications.

Insulation properties enhancement of crosslinked polyethylene by grafting electron‐buffering voltage stabilizers

AbstractGrafting a voltage stabilizer on molecular chains of cross‐linked polyethylene (XLPE) can effectively improve the materials' insulation properties. Four different samples (XLPE, XLPE grafted with the voltage stabilizer, low‐density polyethylene (LDPE) blended with the voltage stabilizer, and LDPE grafted with the voltage stabilizer) are prepared in this paper. Several physicochemical and dielectric tests are performed to investigate the properties of the samples. The results demonstrate that the m‐aminobenzoic acid is successfully grafted onto the XLPE molecular chain. Moreover, the crosslinking and grafting processes are equally important for enhancing the materials' performance of the XLPE. In addition, the grafted voltage stabilizer negligibly affects the gel content and thermal properties of XLPE. However, it increases the crystallinity but decreases the lamella thickness. Moreover, the XLPE grafted with a voltage stabilizer has lower direct current (DC) electrical conductivity, less aggregation of space charge, and higher DC breakdown strength. The trap distribution results indicate that the voltage stabilizer introduces shallow traps in the sample and the quantum chemical calculations describe that the material bandgap is decreased. Thus, the high‐energy charge carriers are buffered by the newly‐introduced traps and the functional groups, leading to the enhanced material properties of the XLPE.

Eliminating Ambiguities in Electrical Measurements of Advanced Liquid Crystal Materials

Existing and future display and non-display applications of thermotropic liquid crystals rely on the development of new mesogenic materials. Electrical measurements of such materials determine their suitability for a specific application. In the case of molecular liquid crystals, their direct current (DC) electrical conductivity is caused by inorganic and/or organic ions typically present in small quantities even in highly purified materials. Important information about ions in liquid crystals can be obtained by measuring their DC electrical conductivity. Available experimental reports indicate that evaluation of the DC electrical conductivity of liquid crystals is a very non-trivial task as there are many ambiguities. In this paper, we discuss how to eliminate ambiguities in electrical measurements of liquid crystals by considering interactions between ions and substrates of a liquid crystal cell. In addition, we analyze factors affecting a proper evaluation of DC electrical conductivity of advanced multifunctional materials composed of liquid crystals and nanoparticles.

Green Energy Generated in Single-Chamber Microbial Fuel Cells Using Tomato Waste

This research used tomato waste as a substrate (fuel) in Single Chamber-Microbial Fuel Cells (scMFC) on a small scale. The electrochemical properties were monitored, the functional groups of the substrate were analyzed by Fourier Transform Infrared Spectrophotometry (FTIR) and a microbiological analysis was performed on the electrodes in order to identify the microorganisms responsible for the electrochemical process. The results show voltage peaks and an electrical current of 3.647 ± 0.157 mA and 0.957 ± 0.246 V. A pH of 5.32 ± 0.26 was measured in the substrate with an electrical current conductivity of 148,701 ± 5849 mS/cm and an internal resistance (Rint) of 77. 517 ± 8.541 Ω. The maximum power density (PD) displayed was 264.72 ± 3.54 mW/cm2 at a current density (CD) of 4.388 A/cm2. On the other hand, the FTIR spectrum showed a more intense decrease in its peaks, with the compound belonging to the phenolic groups being the most affected at 3361 cm−1. The micrographs show the formation of a porous biofilm where molecular identification allowed the identification of two bacteria (Proteus vulgaris and Proteus vulgaris) and a yeast (Yarrowia lipolytica) with 100% identity. The data found show the potential of this waste as a source of fuel for the generation of an electric current in a sustainable and environmentally friendly way, generating in the near future a mechanism for the reuse of waste in a beneficial way for farmers, communities and agro-industrial companies.

Preparation and properties of double percolated co-continuous PC/PET/MWCNT/GNP engineering polymer blend nanocomposites

This study reports on the preparation and characterization of nanocomposites based on polycarbonate (PC)/poly ethylene terephthalate (PET) blend containing low amounts of hybrid of multiwalled carbon nanotube (MWCNTs) and graphene nanoplates (GNPs) by melt mixing. To use double percolation mechanism, at first a co-continuous polymer blend was prepared and the influence of nanofiller content on morphology, electrical conductivity, rheological and mechanical properties of co-continuous PC/PET blend was investigated. Blend containing 60 wt. % PET showed co-continuous morphology as observed by scanning electron microscopy and it was found that co-continuity remained unchanged by the addition of nanofillers. The direct current (DC) electrical conductivity results showed a low electrical percolation threshold around 0.5 phr. The results obtained from differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) showed an increase in thermal stability and crystallinity of nanocomposites. By increasing nanofiller amount, the storage modulus, loss modulus, and complex viscosity of samples increased as an indication of the strong network formation between nanofillers and polymer chains. The rheological percolation threshold was also found in the range of 2.5–3.5 phr of nanofillers. The tensile measurements results showed that the addition PC to PET increases the tensile strength of PET.

Charge transport properties in a novel holographic quantum phase transition model

We investigate the features of charge transport in a novel holographic quantum phase transition (QPT) model with two metallic phases: normal metallic and novel metallic. The scaling behaviors of direct current (DC) resistivity and thermal conductivity at low temperatures in both metallic phases are numerically computed. The numerical results and the analytical ones governed by the near horizon geometry agree perfectly. Then, the features of low-frequency alternating current (AC) electric conductivity are systematically investigated. A remarkable characteristic is that the normal metallic phase is a coherent system, whereas the novel metallic phase is an incoherent system with non-vanishing intrinsic conductivity. Especially, in the novel metallic phase, the incoherent behavior becomes stronger when the strength of the momentum dissipation enhances.