Synthesis and characterization of co-doped ceria-based electrolyte material for low temperature solid oxide fuel cell

Co-doped CeO₂ (Ba_0.10Ga_0.10Ce_0.80O_3–δ) was synthesized via a cost-effective co-precipitation technique, and the electrochemical properties of the solid oxide fuel cell were studied. The microstructural and surface morphological properties were investigated by XRD and SEM, respectively. The structure of the prepared material was found to be cubic fluorite with an average crystallite size of 36?nm. The ionic conductivity of the prepared BGC (Ba_0.10Ga_0.10Ce_0.80O_3–δ) electrolyte material was measured as 0.071?S?cm^?1. The activation energy was found to be 0.46?eV using an Arrhenius plot. The maximum power density and current density achieved were 375?mW?cm^?2 and 893?mA?cm^?2, respectively, at 650?°C with hydrogen as a fuel. This study shows that the prepared co-doped electrolyte material could be used as a potential electrolyte to lower the operating temperature of solid oxide fuel cells.     

Structural and electrical characterisation of nanostructure electrodes for SOFCs

This paper reports the effects of sintering temperature on structure, particle size and conductivity of electrodes (Sn_0.2Zn_0.8Fe_0.2O & Sn_0.8Zn_0.2Fe_0.2O). The electrode material was prepared by the chemical method combining a solid state reaction. Structural analyses were performed using X-ray diffraction and scanning electron microscopy. The particle size of the material obtained using Scherrer's formula was 50–60 nm and the nanostructure's surface was studied using electrochemical characterisations tools. Electrical conductivity was determined using the 4-probe DC method, which was compared with the 4-probe AC method. These results suggest a promising substitute for the conventional electrodes of solid oxide fuel cells (SOFCs). It is known that a sintering temperature above 1000 °C causes an increase in density and a reduction of porosity. Therefore, we optimised the sintering temperature at 1000 °C and obtained electrical conductivity of about 5 S cm⁻¹. Thus, this electrode could play a vital role in the development of high performance SOFCs at intermediate temperatures.     

Quantum mechanical interpretation and analysis of perovskite material based single layer fuel cells (SLFCs)

Fossil fuels are unable to meet the current energy demands and polluting the environment with the emission of harmful gases. Therefore, clean energy technology is need of the modern era. One of the energy conversion devices is fuel cell which utilized fuel from renewable sources and convert into electricity in an efficient and clean way. However, for commercialization of this technology high operating temperature, degradation of electrodes and manufacture cost is the key challenges in conventional three layer fuel cell. Significant improvements have been made to reduce the cost and operating temperature by selecting suitable materials. Therefore, single layer fuel cell (SLFC) has been got much attention due to simple geometry. The mechanism inside the SLFC is still mystery which has been explained in this paper using quantum mechanical parameters like band gap and effect of particle size on charge transportation.In this research work, nanocomposite materials for single layer fuel cell have been synthesized by chemical routes. The x-ray diffraction shows the cubic perovskite structure with average crystallite size in the range of 23–37 nm. The particle size and surface area is found to be 23 nm and 86.42 m² g^?1, respectively. Raman spectrum of LBSCF-SDC shows a red shift compared to LBSCF and band gap of the composition 3LBSCF-7SDC is found to be 2.51 eV. Moreover, the conductivity of the sample 3LBSCF-7SDC has been found to be 0.02 Scm^?1 at 750 °C. The quantum mechanical effects governing the working of single layer fuel cells are observed by different analyses. Photon confinement and Fano-Interactions phenomena resulted in a red shift using Raman analysis technique. The red shift in Raman spectrum is referred to a photon confined in a single layer fuel cell system. These effects are studied in single layer fuel cell for the first time with no previous analyses done in this newly field.     

Mesh adaptive direct search approach for D2D resource management

Device‐to‐device (D2D) communications are being considered a way forward to achieve higher data rate targets for futuristic wireless networks. D2D introduces interference among cellular users and D2D users. A joint resource allocation (JRA) strategy in cellular network with D2D functionality can definitely enhance overall data rate. The strategy under consideration maximizes the overall data rate of cellular network besides meeting threshold of power and interference constraints. The JRA is a class of mixed integer non‐linear constraint optimization problems and is NP hard. Because of discrete nature of variables in the problem, optimal solution performs extensive search of integer variables, and problem becomes exponentially complex with the increasing number of user pairs. In this paper, mesh adaptive direct search algorithm is applied to solve the aforementioned problem. The algorithm is suitable for complex problems of combinatorial nature to solve the JRA strategy in D2D. The proposed algorithm converges to optimal solution within acceptable computational iterations. Simulation results of system capacity and interference also demonstrate the suitability of the proposed approach viz‐a‐viz other algorithms. Copyright © 2016 John Wiley & Sons, Ltd.     

An Overview of Computer-aided Molecular and Process Design

Identifying sustainable chemical processes often depends on the choice of enabling materials that directly influence the overall performance. Matching property targets while incorporating adequate process knowledge is essential for optimal material selection. Multi-scale decisions need to be taken simultaneously to determine the optimal process configurations, operating conditions, and material structures. Integrating molecular to process scale decisions within an equation-oriented optimization framework leads to large-scale mixed-integer nonlinear programs (MINLP). Over the years, several solution approaches have been suggested to tackle this issue. Here, the current state-of-the-art in the field of computer-aided molecular and process design (CAMPD) is discussed and key challenges and open questions are highlighted that may stimulate future research.     

Loss of heterozygosity and mutational analysis of the PTEN/MMAC1 gene in synchronous endometrial and ovarian carcinomas

Mutations of the human putative protein tyrosine phosphatase (PTEN/MMAC1) gene at chromosome 10q23 have been found frequently in type I endometrial carcinomas. Endometrioid adenocarcinoma is the most frequent histology seen in patients with clinically determined synchronous endometrial and ovarian carcinomas. We report a high incidence of PTEN/MMAC1 mutations and 10q23 loss of heterozygosity (LOH) in patients with synchronous endometrial and ovarian carcinomas. Paraffin-embedded precision microdissected tumors were analyzed for 10 matched synchronous endometrial and ovarian cancers and 11 matched control metastatic endometrial cancers. Single-stranded conformation polymorphism analysis was used to screen for mutations in all tumors and corresponding normal lymphocyte DNA. LOH was determined using a panel of four microsatellite markers within the PTEN/MMAC1 locus. PTEN/MMAC1 mutations were found in 43% (9 of 21) of the endometrial cancers studied, similarly represented in the clinically synchronous group (5 of 10 or 50%) and the advanced metastatic group (4 of 11; 36%; P = 0.53). In two of the five cases of clinically synchronous cancers, identical or progressive PTEN mutations were found in both the endometrial and ovarian cancers, suggesting that the ovarian tumor is a metastasis from the endometrial primary. PTEN/MMAC1 mutations in the advanced endometrial cancers were similar in the corresponding metastases. In one case, the mutation was seen in only one of two metastatic lymph nodes. The LOH analysis demonstrated 55% LOH in at least one PTEN/MMAC1 marker. These findings suggest that the putative tumor suppressor gene PTEN/MMAC1 may be a viable molecular marker to differentiate synchronous versus metastatic disease in a subset of clinically synchronous endometrial and ovarian carcinomas.     

Calling for backup [power system reliability]

In this paper, the importance of, and key design issues for, backup control centers (BCC) in maintaining power system reliability are discussed. It also highlights the importance of the key factors incorporated into the initial design studies of the BCC of the Alberta Electric System Operator (AESO) and may help other utilities that might want to implement a similar backup facility at their premises.     

Robust audio watermarking using frequency-selective spread spectrum

A novel audio watermarking scheme based on frequency-selective spread spectrum (FSSS) technique is presented. Unlike most of the existing spread spectrum (SS) watermarking schemes that use the entire audible frequency range for watermark embedding, the proposed scheme randomly selects subband(s) signal(s) of the host audio signal for watermark embedding. The proposed FSSS scheme provides a natural mechanism to exploit the band-dependent frequency-masking characteristics of the human auditory system to ensure the fidelity of the host audio signal and the robustness of the embedded information. Key attributes of the proposed scheme include reduced host interference in watermark detection, better fidelity, secure embedding and improved multiple watermark embedding capability. To detect the embedded watermark, two blind watermark detection methods are examined, one based on normalised correlation and the other based on estimation correlation. Extensive simulation results are presented to analyse the performance of the proposed scheme for various signal manipulations and standard benchmark attacks. A comparison with the existing fullband SS-based schemes is also provided to show the improved performance of the proposed scheme.     

All-organic PANI–DBSA/PVDF dielectric composites with unique electrical properties

Novel all-organic polymer high-dielectric permittivity composites of polyaniline (PANI)/poly (vinylidene fluoride) (PVDF) were prepared by solution method and their dielectric and electric properties were studied over the wide ranges of temperatures and frequencies. To improve the interface bonding between two polymers, dodecylbenzenesulfonic acid (DBSA), a bulky molecule containing a polar head and a long non-polar chain was used both as a surfactant and as dopant in polyaniline (PANI) synthesis. Synthesized conducting PANI–DBSA particles were dispersed in poly(vinylidene fluoride) (PVDF) matrix to form an all-organic composite with different PANI–DBSA concentrations. Near the percolation threshold, the dielectric permittivity of the composites at 100 Hz frequency and room temperature was as high as 170, while the dielectric loss tangent value was as low as 0.9. Like typical percolation system, composites experienced high dielectric permittivity at low filler concentrations. However, their dielectric loss tangent was low enough to match with non-percolative ceramic filler-based polymer composites. Maximum electrical conductivity at 24 wt% of PANI–DBSA was mere 10^?6 S/cm, a remarkably low value for percolative-type composites. Increase in the dielectric permittivity of the composites with increase in temperature from 25 to 115 °C for different PANI–DBSA concentrations was always in the same range of 50–60 %. However, the degree of increase in the electrical conductivity with the temperature was more prominent at low filler concentrations compared with high filler concentrations. Distinct electrical and their unique thermal dependence were attributed to an improved interface between the filler and the polymer matrix.