A novel blended solid polymer electrolyte comprising polyethylene oxide and polyvinylpyrrolidone polymers for blending and sodium nitrate (NaNO3) as ion conducting species has been optimized via standard solution-cast technique. XRD, FESEM, and FTIR were performed to obtain the information about the structural changes, morphology, and microstructural changes (polymer–ion and ion–ion interactions) of the solid polymer electrolyte films. The electrochemical impedance spectroscopy, linear sweep voltammetry, and i–t characteristics were performed to evaluate the ionic conductivity, voltage stability window, and ion transference number. The impedance study was done in a broad temperature range (40–100 °C). The DSC and TGA were used to obtain information about the thermal transitions and thermal stability of prepared films. The ion dynamics is further investigated by analyzing the complex permittivity, loss tangent, and complex conductivity. All the plots were fitted through established theoretical model/expressions in whole frequency window to obtain dielectric strength, ion conduction path behavior, and relaxation time. Transport parameters such as number density (n), mobility (μ), and diffusion coefficient (D) of mobile ions were obtained by three methods and compared satisfactorily. Lastly, a coherent mechanism for the migration of charge transport carriers within the solid polymer composites has been proposed based on the performed experimental outcome.

Dielectric relaxations and transport properties parameter analysis of novel blended solid polymer electrolyte for sodium-ion rechargeable batteries

Detecting selective forwarding attacks in wireless sensor networks

The present paper is focused toward the preparation of the flexible and free-standing blend solid polymer electrolyte films based on PEO-PVP complexed with NaPF6 by the solution cast technique. The structural/morphological features of the synthesized polymer nanocomposite films have been investigated in detail using X-ray diffraction, Fourier transform infra-red spectroscopy, Field emission scanning electron microscope, and Atomic force microscopy techniques. The film PEO-PVP + NaPF6 (
 $$ \ddot{\mathrm{O}}/{\mathrm{Na}}^{+}= $$
 8) exhibits highest ionic conductivity ~ 5.92 × 10−6 S cm−1 at 40 °C and ~ 2.46 × 10−4 S cm−1 at 100 °C. The temperature-dependent conductivity shows an Arrhenius type behavior and activation energy decreases with the addition of salt. The high temperature (100 °C) conductivity monitoring is done for the optimized PEO-PVP + NaPF6 (
 $$ \ddot{\mathrm{O}}/{\mathrm{Na}}^{+}= $$
 8) highly conductive system and the conductivity is still maintained stable up to 160 h (approx. 7 days). The thermal transitions parameters were measured by the differential scanning calorimetry (DSC) measurements. The prepared polymer electrolyte film displays the smoother surface on addition of salt and a thermal stability up to 300 °C. The ion transference number (tion) for the highest conducting sample is found to be 0.997 and evidence that the present system is ion dominating with negligible electron contribution. Both linear sweep voltammetry and cyclic voltammetry supports the use of prepared polymer electrolyte with long-term cycle stability and thermal stability for the solid-state sodium ion batteries. Finally, a two peak percolation mechanism has been proposed on the basis of experimental findings.

Optimization of salt concentration and explanation of two peak percolation in blend solid polymer nanocomposite films

In this paper, we report the investigation on structural, electrical, dielectric properties, and ion dynamics of novel blend polymer electrolyte matrix (PEO-PEI) complexed with sodium hexafluorophosphate salt. All the solid polymer electrolyte films have been synthesized via solution cast method. The SPE films were characterized by the X-ray diffraction, field emission scanning electron microscope, impedance-dielectric spectroscopy, and thermogravimetric analysis. The morphology of the SPE alters with salt addition and confirms the blend polymer complex formation. The FTIR analysis evidenced the complex formation, and increase in the fraction of free ions is achieved. The ionic conductivity exhibits a maximum at the stoichiometric ratio O/Na = 10 and follows the Arrhenius behavior. The fraction of free ions is maximum for the SPE film with the highest ionic conductivity. The optimum electrolyte possesses a voltage stability window of about 4 V, excellent thermal stability up to 380 °C, and high ionic transference number (~ 1). The complex permittivity and conductivity have been simulated in whole frequency window to extract relaxation time and dielectric strength. The dielectric constant and relaxation time exhibited sequentially a maximum and minimum for the SPE film with the highest ionic conductivity. The loss tangent peak shifts toward high frequency with addition of salt, and it infers the faster ion dynamics in the polymer matrix. Then the ion transport parameters number density of charge carriers (n), ion mobility (μ), and diffusion coefficient (D) have been obtained by three methods (FTIR, impedance spectroscopy, and loss tangent method) and are in absolute correlation with the impedance results. An ion transport mechanism has been proposed based on experimental findings.

Selection of best composition of Na + ion conducting PEO-PEI blend solid polymer electrolyte based on structural, electrical, and dielectric spectroscopic analysis

Blended solid polymeric thin films based on PEO–PVP complexed with LiBOB were synthesized by solution cast technique. The effect of salt on morphology, structure and electrochemical properties was examined. The XRD and FESEM analyses reveal the enhancement of amorphous content on salt addition. The FTIR spectroscopy evidences the complex formation and presence of various microscopic interactions. The ionic conductivity for the optimized system has been estimated and found to be two orders higher than the salt-free system, i.e., ~ 5.1 × 10−6 S cm−1 (@40 °C), and remains increasing with temperature i.e. 6.5 × 10−4 S cm−1 (@100 °C) for O/Li = 16. The enhancement of ionic conductivity is attributed to increase in the number density of mobile ions as concluded by the Rice and Roth model. The high tion (~ 0.99) evidences the ionic nature of complexed electrolyte. DSC analysis evidences the suppression of crystallinity and shift of glass transition and melting temperature toward lower temperature implies the enhancement of the amorphous content and forms the rubbery nature of the thin films which support the faster ion conductions. Finally, an interaction scheme is proposed for a better explanation of the ion transport on the basis of experimental findings.

Structural, electrical and ion transport properties of free-standing blended solid polymeric thin films

Sodium ion conducting polymer electrolyte films based on Poly (ethylene oxide) PEO/Poly (ethyl methacrylate) PEMA have been prepared by solution-cast technique in various concentrations. Miscibility studies of the electrolytes were investigated by X-ray diffraction (XRD) and the results show that the highest conducting film is the most amorphous. Frequency dependent conductivity (σac) values were obtained from complex impedance (colecole) plots. It was observed that the magnitude of conductivity increased both with the increase in the salt concentration and the temperature. The charge transport of these electrolytes is mainly due to ions which were confirmed by the transference number experiment. Using this electrolyte, cells were fabricated and their discharge profiles were studied under constant load. Several cell parameters associated with the cells were evaluated and compared with earlier reports.

/pdf/investigations-on-conductivity-and-discharge-profiles-of-3utb6qsyaw.pdf

Investigations on conductivity and discharge profiles of novel (peo+pema) polymer blendelectrolyte

The demand for oil is growing steadily from emerging and developing economies while oil field discoveries continue to decline. Therefore the gap between demand and supply will increase with time. Subsurface Exploration deals with extracting valuable hydrocarbons from oil wells. Due to its hazardous nature, it’s one of the most difficult fields to carry experimentations on. Uncertainties associated with this field are result of various factors such as lack of information regarding location, size and spread of natural resource. In order to handle above listed factors, mobile wireless sensors seems to be a promising paradigm for increasing productivity and throughput by serving as intelligent investigators. At the time of this listing, none of the researchers have proposed the deployment of mobile wireless sensors in the oil fields. Therefore, this work contributes a unique strategy that could deploy mobile sensors in the subsurface so as to get real time information which otherwise is not possible. Moreover, the proposed algorithm provides efficient coverage and connectivity metric. Also, a mathematical model has been presented along with its comparison with other existing node placement strategies in other related fields and it is found that our algorithm provides better coverage and connectivity.

/pdf/a-novel-and-efficient-algorithm-for-deploying-mobile-sensors-ccwpfk372z.pdf

A Novel and Efficient Algorithm for Deploying Mobile Sensors in Subsurface

If sensor networks are to attain their potential, security is one of the most important aspects to be taken care of. The need for security in military applications is obvious, but even more benign uses, such as home health monitoring, habitat monitoring and sub-surface exploration require confidentiality. WSNs are perfect for detecting environmental, biological, or chemical threats over large scale areas, but maliciously induced false alarms could completely negate value of the system. The widespread deployment of sensor networks is directly related to their security strength. These stated facts form the basis for this survey paper. This paper present a brief overview of challenges in designing a security mechanism for WSN, classify different types of attacks and lists available protocols, while laying outline for proposed work.

Wireless Sensor Network Security Research and Challenges: A Backdrop

Due to the global recession the cost of raw materials used in handmade paper industry in India are increasing one side and on the other side the export market is badly affected. Also, the capital costs are going higher day by day thus forcing the Indian handmade paper industry on back foot. Keeping in mind the present research work with the aims to help the handmade paper industry in different parts of the country so that they come out with the problem of good quality natural lingocellulosic raw materials. The ligno-cellulosic raw materials Banana (Musa sapientum), Ankara (Calotropis procera), and Pineapple (Ananas comosus) which are locally available may be used by the Industry in India. The research paper covers the potentiality about the fibres and its morphological & chemical nature as well as the alkaline sulphite pulping technology. The chemical characteristics of these fibres i.e. lower lignin content, higher alpha cellulose coupled with average higher fibre length could prove its applicability for the manufacture of a good quality handmade papers and converted paper products. As a reinforcing fibre by blending these fibres with the traditionally used hosiery waste could find suitable place as an alternate raw materials with a better strength properties. The present paper special attentions were given to banana fibre which deals with chemical pulping technologies like alkaline sulphite pulping for the production of pulp. The resultant spent liquor obtained from banana cooked sulphite pulping process has been found to be useful as a plasticizer in concrete admixture.

/pdf/blending-studies-of-hosiery-waste-pulp-withalkaline-sulphite-2qb6mfw8f3.pdf

Blending Studies of Hosiery Waste Pulp withAlkaline Sulphite Cooked Pulp of NaturalFibres & the Use of Lignosulphonate

The Semantic Web (SW) deals with transforming the information-oriented web into a knowledge-oriented web. SW makes product and service information more abundant and improves search mechanisms thus resulting in user satisfaction, but lack of standard ontologies and communication interface for a domain is creating a lot of hurdles in its implementation. Considerable research has been focused at overcoming these deficiencies through more efficient agent-oriented interactive algorithms and ontology-based system design. The main focus of this survey is targeted on the recent solutions available for overpowering the explored issues.

A. K. Sharma

Papers

Investigations on conductivity and discharge profiles of novel (peo+pema) polymer blendelectrolyte

A Novel and Efficient Algorithm for Deploying Mobile Sensors in Subsurface

Wireless Sensor Network Security Research and Challenges: A Backdrop

Blending Studies of Hosiery Waste Pulp withAlkaline Sulphite Cooked Pulp of NaturalFibres & the Use of Lignosulphonate

An Extensive Analysis of Implementation Issues in Semantic Web