Benchmarking large-scale data management for Internet of Things

The Journal of Supercomputing - In the current era of the Internet of Things (IoT), massive number of sensors are used in our daily lives. Sensors are everywhere around us. They exist in our homes,...     

KAGO: an approximate adaptive grid-based outlier detection approach using kernel density estimate

Pattern Analysis and Applications - Outlier detection approaches show their efficacy while extracting unforeseen knowledge in domains such as intrusion detection, e-commerce, and fraudulent...     

Heavy Water Additive in Formamidinium: A Novel Approach to Enhance Perovskite Solar Cell Efficiency

Heavy water or deuterium oxide (D₂O) comprises deuterium, a hydrogen isotope twice the mass of hydrogen. Contrary to the disadvantages of deuterated perovskites, such as shorter recombination lifetimes and lower/invariant efficiencies, the serendipitous effect of D₂O as a beneficial solvent additive for enhancing the power conversion efficiency (PCE) of triple-A cation (cesium (Cs)/methylammonium (MA)/formaminidium (FA)) perovskite solar cells from ≈19.2% (reference) to 20.8% (using 1 vol% D₂O) with higher stability is reported. Ultrafast optical spectroscopy confirms passivation of trap states, increased carrier recombination lifetimes, and enhanced charge carrier diffusion lengths in the deuterated samples. Fourier transform infrared spectroscopy and solid-state NMR spectroscopy validate the N–H₂ group as the preferential isotope exchange site. Furthermore, the NMR results reveal the induced alteration of the FA to MA ratio due to deuteration causes a widespread alteration to several dynamic processes that influence the photophysical properties. First-principles density functional theory calculations reveal a decrease in PbI₆ phonon frequencies in the deuterated perovskite lattice. This stabilizes the PbI₆ structures and weakens the electron–LO phonon (Fröhlich) coupling, yielding higher electron mobility. Importantly, these findings demonstrate that selective isotope exchange potentially opens new opportunities for tuning perovskite optoelectronic properties.     

A rare case of Actinomyces skin and soft tissue infection in an end‐stage kidney disease patient with a review of the literature

End‐stage kidney disease (ESKD) patients are a commonly overlooked immunocompromised population that places them at risk for rare infections. We describe the case of a 78‐year‐old man with a history of ESKD managed with thrice weekly in‐center hemodialysis who had a prolonged episode of left elbow pain and drainage and was eventually found to have a skin and soft tissue infection from Actinomyces radingae. We review the bacteriology of Actinomyces spp. and the experiences of other providers who have treated actinomycosis in individuals with ESKD. The anatomic sites and demographics of these individuals are heterogeneous, but they all generally require a long antibiotic course with a beta‐lactam and portend to a good prognosis. High index of suspicion is needed to identify rare and atypical infections in the ESKD population.     

Experimental investigations and comparison of various MPPT techniques for photovoltaic system

This paper deals with Matlab/Simulink and experimental investigations of various maximum power point tracking (MPPT) techniques namely incremental conductance (Inc), perturb and observation (P&O), constant voltage control (CVC) method, and introduction of a novel reference power (Pref) method for extracting the maximum power from the solar photovoltaic (PV) system. The complete system model along with these MPPT methods are developed in Matlab/Simulink and simulation results are obtained during sudden increase in irradiation of 1000 W/m², and verified experimentally. These MPPT methods are also implemented on Inverse-Sepic converter, which claims to extract maximum power from the PV system. Various experimental observations are taken to access the performance of these MPPT techniques such as settling time of the full load current under sudden exposure of irradiation level of 1000 W/m², performance during step increase in irradiation level (from 500 W/m² to 1000 W/m²) and vice versa. Extensive results are taken to compare these methods. The proposed Pref method is found to have lowest settling time to stabilize the load current as 520 ms, whereas, Inc method takes 1.24 s. Further, the efficiency of Inverse-Sepic converter with Pref method achieves the highest efficiency of 95.26%, whereas, it extracts lowest efficiency on same input as 90.77% with P&O method. The overall performance of the proposed Pref method is found to be superior as compared to other discussed MPPT methods as verified by experimental results.     

Development of halogen‐free flame‐retardant thermoplastic elastomer polymer blend

Ethylene‐propylene diene rubber (EPDM) and isotactic polypropylene (iPP) blends have widest industrial applications that require a degree of flame retardancy. Halogen‐free intumescent technology based on phosphorous salt is a significantly advanced approach to make the polymer flame‐retardant. Both ammonium polyphosphate and ethylenediamine phosphate are important intumescent compounds. Their combination with carbonific and spumific agents were studied in binary blends of EPDM/PP. The polymer system was vulcanized online during melt mixing. Intumescent flame‐retardant polymer systems exhibit good flame‐retardancy with optimum comparable physiomechanical, electrical, and fluid resistance properties, including lower smoke emission, which is essential to protect people because the visibility remains unaffected in the event of fire. Pronounced charring and intumescent effect appear to enhance the flame‐retardancy of the polymers. Possible expected intumescent mechanism is proposed based on the nonpyrolysis mechanism for the flame‐retarded polymer and the intumescent components. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 407–415, 2004     

Integration of Kano’s Model into quality function deployment (QFD)

Viability of a product or service in the market depends upon the satisfaction that it can extend to its customers through quality. Quality function deployment (QFD) is a tool that gathers voice of customer (VoC) and inducting the expected features in the final product. It is also desirable that the practitioners of QFD must extend due importance to latent expectations of the customers, which in turn may fulfill overall customer satisfaction for a product or service. Kano et al. (J Jpn Soc Qual Control, 14:39–48, 1984; 1996) and Kano (2001) have suggested a method to identify the different categories of requirements through customer responses. Based on the QFD and Kano model analysis, a function has been proposed to adjust the traditional improvement ratio (Tan and Shen, Total Qual Manag 11:1141–1151, 2000) for each product or service attribute to recognize the importance of a attribute, which can be helpful in developing a product or service in such a manner that maximum customer satisfaction can be achieved. The proposed methodology has been illustrated using customer survey data.     

Magnetic and dielectric studies of barium hexaferrite (BaFe 12 O 19 ) ceramic synthesized by chemical route

Barium hexaferrite BaFe12O19 (BHF) ceramic was synthesized by chemical route on sintering at 1050 °C for 12 h. The synthesized material was characterized by XRD, SEM, AFM and TEM analysis. Metal oxide stretching frequencies corresponding to Fe-O, Ba-O, and Fe-O-Fe bands are confirmed by FTIR studies. The hexagonal nature of the BHF ceramic was confirmed by TEM analysis and Rietveld refinement with space group P63/mmc. The particle size observed by TEM is 175 nm. The root means square and average roughness were found to be 61.048 nm and 44.025 nm respectively. The M-T and M-H hysteresis loop indicates temperature dependent ferromagnetic behavior of BHF ceramic. The temperature and frequency dependent dielectric properties were explained by Maxwell-Wagner theory. The value of dielectric constant (ε′) for BHF ceramic was found to be 22× 103 at 100 Hz and 483 K.