Electric and dielectric properties of solution-gas interface-grown PbS films

Dielectric properties andI–V characteristics of solution-gas interface-formed PbS thin-film capacitors (Al/PbS/Al) of various thicknesses have been studied in the frequency range 10-10⁶ Hz at various temperatures (300–443 K). Current-voltage (I–V) characteristics show space-charge-limited conduction. Dielectric constant (ε) increases with increasing film thickness and temperature and decreases with increase of frequency. The loss factor (tanδ) peaks observed in tanδ vs frequency and tanδ vs temperature reveal relaxation effect from dipolar orientation. These maxima shift to higher-temperature region with increasing frequency. The large increase in capacitance (C) and dielectric constant (ε) towards low-frequency (f) region indicates the possibility of an interfacial polarization mechanism in this region.     

Indium selenide microrod films: chemical bath deposition from acidic bath

Films of indium selenide was deposited onto glass and indium tin oxide coated glass substrates in acidic medium using chemical bath deposition at room temperature. Indium sulphate and sodium selenosulphate were used as precursors of In³⁺ and Se^2?, respectively. The structural, surface morphological and optical properties of the deposited films were studied. Diffractograms in structural study revealed the deposited material is In₂Se₃ films. Controlled bath conditions resulted in the evolution of the In₂Se₃ microrod-like morphology. The optical band gap of the film was found to be 1.7 eV.     

Effect of pH on the detailed chemical nature and metal-carbonate species in as synthesized zirconia alumina composites

Zirconia was deposition precipitated on γ-alumina in pH range 7-10 from zirconium oxy-nitrate and soda ash. Zirconium formed its hydroxycarbonate as deduced from ICP-EOS, CHN, and TGA-MS. Higher pH favored formation of carbonate species of zirconium over its hydroxide. TGA-MS indicated formation of three different types of carbonate species. FTIR results corroborated this. Monodentate metal carbonate was observed irrespective of pH of preparation. In addition, bridged bidentate species formed at pH ≤ 8 which changed to chelating bidentate at pH > 8. XRD indicated that all the samples formed tetragonal-zirconia upon calcination irrespective of pH of preparation. Higher pH resulted in smaller crystallites of t-ZrO₂. Changes in chemical moiety with pH reflected on acidity and the deactivation rate for 2-methyl-3-butyn-2-ol which decreased by two orders of magnitude in samples prepared at higher pH. Surface area and pore volume benefited from deposition precipitation. SEM-EDAX showed reasonable distribution of zirconia over γ-Al₂O₃.     

Cloud-assisted body area networks: state-of-the-art and future challenges

Body area networks (BANs) are emerging as enabling technology for many human-centered application domains such as health-care, sport, fitness, wellness, ergonomics, emergency, safety, security, and sociality. A BAN, which basically consists of wireless wearable sensor nodes usually coordinated by a static or mobile device, is mainly exploited to monitor single assisted livings. Data generated by a BAN can be processed in real-time by the BAN coordinator and/or transmitted to a server-side for online/offline processing and long-term storing. A network of BANs worn by a community of people produces large amount of contextual data that require a scalable and efficient approach for elaboration and storage. Cloud computing can provide a flexible storage and processing infrastructure to perform both online and offline analysis of body sensor data streams. In this paper, we motivate the introduction of Cloud-assisted BANs along with the main challenges that need to be addressed for their development and management. The current state-of-the-art is overviewed and framed according to the main requirements for effective Cloud-assisted BAN architectures. Finally, relevant open research issues in terms of efficiency, scalability, security, interoperability, prototyping, dynamic deployment and management, are discussed.     

Nanocrystalline Pt-doped TiO2 thin films prepared by spray pyrolysis for hydrogen gas detection

Nanostructured pure and Pt-doped TiO₂ thin films were prepared by chemical spray pyrolysis technique. Aqueous solution of TiCl₃·6H₂O (0·01 M) was chosen as the starting solution for the preparation of pure TiO₂ thin film. Aqueous solutions of PtCl₆·6H₂O (0·01 M) and TiCl₃·6H₂O (0·01 M) were mixed in volume % of 1 : 99, 2·5 : 97·5 and 5 : 95 respectively to obtain Pt-doped TiO₂ thin films. The solutions were sprayed onto quartz substrate heated at 350 °C temperature to obtain the films. These thin films were fired for one hour at 550 °C. The sensing performance of these films was tested for various gases such as LPG, H₂, CO₂, ethanol, NH₃ and Cl₂ (1000 ppm). The Pt-doped TiO₂ (1 : 99) was observed to be most sensitive (572) to H₂ at 400 °C with high selectivity against other gases. Its response time was short (10 s) and recovery was also fast (14 s). To understand the reasons behind the gas-sensing performance of the films, their structural and microstructral properties were studied using X-ray diffraction and electron microscopy (FE–SEM and TEM), respectively. Thicknesses of all these samples were determined using Surface Profiler. The results are interpreted.     

Real-time scheduling algorithm for safety-critical systems on faulty multicore environments

An algorithm (called FTM) for scheduling of real-time sporadic tasks on a multicore platform is proposed. Each task has a deadline by which it must complete its non-erroneous execution. The FTM algorithm executes backups in order to recover from errors caused by non-permanent and permanent hardware faults. The worst-case schedulability analysis of FTM algorithm is presented considering an application-level error model, which is independent of the stochastic behavior of the underlying hardware-level fault model. Then, the stochastic behavior of hardware-level fault model is plugged in to the analysis to derive the probability of meeting all the deadlines. Such probabilistic guarantee is the level of assurance (i.e., reliability) regarding the correct functional and timing behaviors of the system. One of the salient features of FTM algorithm is that it executes some backups in active redundancy to exploit the parallel multicore architecture while other backups passively to avoid unnecessary execution of too many active backups. This paper also proposes a scheme to determine for each task the number of backups that should run in active redundancy in order to increase the probability of meeting all the deadlines. The effectiveness of the proposed approach is demonstrated using an example application.     

Curcumin loaded fish scale collagen-HPMC nanogel for wound healing application: Ex-vivo and In-vivo evaluation

The objective of the present investigation was to formulate curcumin loaded fish scale collagen (FSC)-hydroxypropyl methyl cellulose (HPMC K100) nanogel (CNG) for wound healing application. The curcumin nanoemulsion was prepared, characterized and loaded in FSC-HPMC nanogel. The nanogel was evaluated for ex-vivo permeation, in-vivo, skin irritation, and stability study. Ex-vivo permeation study demonstrated that CNG prolonged release and exhibited higher percent contraction value of wound compared to other formulations. In skin irritation study, formulation produced the score of less than 2 compared to control. It concluded that curcumin loaded FSC-HPMC nanogel could be prepared for wound healing applications.     

A two-stage approach for task and resource management in multimedia cloud environment

In recent years, multimedia cloud computing is becoming a promising technology that can effectively process multimedia services and provide quality of service (QoS) provisioning for multimedia applications from anywhere, at any time and on any device at lower costs. However, there are two major challenges exist in this emerging computing paradigm: one is task management, which maps multimedia tasks to virtual machines, and the other is resource management, which maps virtual machines (VMs) to physical servers. In this study, we aim at providing an efficient solution that jointly addresses these challenges. In particular, a queuing based approach for task management and a heuristic algorithm for resource management are proposed. By adopting allocation deadline in each VM request, both task manager and VM allocator receive better chances to optimize the cost while satisfying the constraints on the quality of multimedia service. Various simulations were conducted to validate the efficiency of the proposed task and resource management approaches. The results showed that the proposed solutions provided better performance as compared to the existing state-of-the-art approaches.     

Big data challenges: Prioritizing by decision-making process using Analytic Network Process technique

Multimedia Tools and Applications - This paper presents an innovative technique to find out the most influential challenge faced by big data. Presently, the key challenges faced by big data are...