Hydrocyclone Performance with Complex Oil‐Water Emulsions in the Feed

Separation performance of an oil‐water hydrocyclone depends very much on the physical properties of the feed emulsion or dispersion. These properties can be influenced by numerous factors, particularly water cut and the type of emulsion.In this exploratory work, the effects of water cut and flowrate on de‐watering capabilities of a hydrocyclone with a complex emulsion in the feed line are investigated. Two flow rates of 25 and 35L/min were studied and the water cut was varied from about 8 to 65%. For each case separation, efficiency was measured, the emulsion characterized and its stability checked for the three hydrocyclone streams. Drop size distribution was also examined. Comparison of performance with a simple emulsion was also made.     

Robust learning of automatic classes of languages

One of the most important paradigms in the inductive inference literature is that of robust learning. This paper adapts and investigates the paradigm of robust learning to learning languages from positive data. Broadening the scope of that paradigm is important: robustness captures a form of invariance of learnability under admissible transformations on the object of study; hence, it is a very desirable property. The key to defining robust learning of languages is to impose that the latter be automatic, that is, recognisable by a finite automaton. The invariance property used to capture robustness can then naturally be defined in terms of first-order definable operators, called translators. For several learning criteria amongst a selection of learning criteria investigated either in the literature on explanatory learning from positive data or in the literature on query learning, we characterise the classes of languages all of whose translations are learnable under that criterion.     

Model based on matern process for ICI mitigation in multi cell cooperation

Ever increasing need of data rate and coverage can be achieved by mitigating the impairments of wireless communication system. Inter cell interference (ICI) is one of the most challenging impairment of wireless communication. To mitigate ICI, multi cell cooperation (MCC) based technique has been proposed in literature. In this paper, ICI mitigation is achieved by using Matérn Hard-Core Point Process (MHCP) instead of Poisson point process (PPP). In MHCP a minimum distance between base stations is maintained. Therefore, MHCP corresponds to real deployment scenario. Also, use of MHCP reduces the analytical complexity significantly compared to that of PPP. A closed form expression for complementary cumulative distribution function (CCDF) of signal-to-interference ratio is derived using MHCP for MCC based system in terms of number of base stations, number of antennas and path loss. Using derived expression of CCDF, analytical expressions for probability density function and ergodic capacity is also presented in the closed form. Finally, performance analysis is shown in terms of ergodic capacity. Results are validated by comparing the proposed results with [4].     

The Implications of Cognitive Femtocell Based Spectrum Allocation Over Macrocell Networks

We propose an analytical framework of significant influence of deployment of femto base stations (FBSs) in a dual-tier network constituted of macro base stations (MBSs). As because of uncoordinated deployment, FBSs results in destructive interference to MBSs and vice versa. But, throughput efficiency of indoor (femtocell) and outdoor (macrocell) environment substantially increases due to an optimum reutilization of available spectrum. The quality of service is further getting optimized in terms of throughput and network coverage because of incorporation of steerable beamforming. Finally, the effectiveness of the scheme is verified by extensive matlab simulation.     

Substrate temperature-dependent physical properties of nanocrystalline zirconium titanate thin films

Nanocrystalline zirconium titanate thin films were deposited by direct current magnetron reactive sputtering on to glass substrates at room temperature and at different substrate temperatures of 423, 473, 523, and 573 K under high vacuum conditions. The deposited films have been characterized to study the physical properties of the films as a function of substrate temperature. Though the film exhibited amorphous characteristics at room temperature the higher temperatures resulted in the evolution of crystallites in the films. The crystallinity increased with temperature from 423 K onwards and the film deposited at 523 K exhibited a high crystallite size of 22 nm. The SEM images of the films revealed the improvement in the crystallinity from 423 to 523 K with dense columnar structure normal to the substrate. Further higher treatment deteriorated the film properties. The films showed a good transmittance of above 80%. A high optical transmittance of 91% and a high packing density of 96% have been observed for the film deposited at 523 K. The thickness of the films remained consistent at ~230 nm (±6 nm). It is noticed that an increase in the substrate temperature enhanced the structural, optical, and electrical properties of the films up to 523 K.     

Raw and chemically treated bio-waste filled (Limonia acidissima shell powder) vinyl ester composites: Physical,mechanical, moisture absorption properties,and microstructure analysis

The rapid growth of environmentally sustainable and eco-friendly materials tends to the utilization of biowastes as filler in polymer matrix composites. The particulate composite with improved wettability of fillers and advanced approach can evolve polymer composites that exhibit promising applications in packaging, automobile, marine, construction, and aerospace. In the present work, one of the biowaste fillers were synthesized from Limonia acidissima shells via a top-down approach (pulverizing) and the surfaces were chemically modified using sodium hydroxide (NaOH) before they were used as fillers in vinyl ester polymer composites by different weight percentage (0, 5, 10, 15, and 20 wt%). The prepared particulate composites were characterized by mechanical properties, moisture absorption behavior, and morphology. At different filler loading the tensile strength, tensile modulus, flexural strength, flexural modulus, impact strength, hardness, density, and moisture intake tests were performed. The results reveal that the properties increased for composites filled with alkaline treated fillers for the same filler loading and found to be higher at filler loading of 15 wt%. The morphological analysis confirms the better interfacial bonding between alkali-treated particles and matrix due to the removal of non-cellulose materials from the surface of the particles.     

Design and control of single-phase dynamic voltage restorer

Dynamic voltage restorer (DVR) is a custom power device used in electrical distribution system for power quality improvement. It ensures regulated voltage supply to the sensitive loads, even in case of voltage sag and swell disturbances in the distribution network. It is a series connected device and compensates voltage sag and swell by injecting a voltage with the help of a series transformer. The injection of an appropriate voltage component in the event of a voltage disturbance requires a certain amount of real and reactive power. Conventionally, DVR consists of an energy storage device, which supplies the required power over the limited duration of the sags. Large magnitude and long duration of sags lead to heavy financial investment in energy storage unit. To overcome this limitation, a single-phase back-to-back converter-based DVR is implemented in this work, which eliminates energy storage requirement. The integration of series and shunt converter makes the DVR capable of bidirectional flow of energy. Therefore, the key advantage of this topology is its capability to compensate for long-term voltage sag and swell. Modelling of the DVR and its controller design is included in this paper. The effectiveness of control schemes, protection schemes and starting sequence of operation of DVR is verified through detailed simulation studies. A scaled down laboratory prototype of DVR is developed. The viability of these schemes is confirmed by the experimental results generated from the laboratory prototype. Various challenges faced during the prototype development and corresponding solutions are also discussed in this paper.     

Batch Sample Design from Databases for Logistic Regression

The prevalence of large observational databases offers potential for identifying predictive relationships among variables of interest, although observational data are generally far less informative and less reliable than experimental data. We consider the problem of selecting a subset of records from a large observational database, for the purpose of designing a small but powerful experiment involving the selected records. It is assumed that the database contains the predictor variables but is missing the response variable, and that the purpose is to fit a logistic regression model after the response is obtained via the experiment. Active learning methods, which treat a similar problem, usually select records sequentially and focus on the single objective of classification accuracy. In contrast, many emerging applications require batch sample designs and have a variety of objectives that may include classification accuracy or accuracy of the estimated parameters, the latter being more in line with the optimal design of experiments (DOE) paradigm. The aim of this paper is to explore batch sampling from databases from a DOE perspective, particularly regarding the configuration, performance, and robustness of the designs that result from the different criteria. Through extensive simulation, we show that DOE‐based batch sampling methods can substantially outperform random sampling and the entropy method that is popular in active learning. We also provide insight and guidelines for selecting appropriate design criteria and modeling assumptions. Copyright © 2016 John Wiley & Sons, Ltd.     

Electrospun polyurethane and soy protein nanofibres for wound dressing applications

In this report, a novel wound dressing material has been woven by electrospinning technique and tested for its various properties. For the nanofibre mat, a mixture of polyurethane (PU) and soy protein isolate (SPI) was electrospun in conjugation with zinc oxide nanoparticles (ZnO Nps) and ciprofloxacin hydrochloride (CipHCl) to produce fibrous mats viz. PU/SPI/ZnO and PU/SPI/CipHCl. An optimum ratio (1 : 1) of PU/SPI was used as suitable polymeric ratio in order to produce homogenous nanofibres without beads having an average diameter in the range of 300–350 nm. The electrospun nanofibre‐based mats were characterised using X‐ray diffraction, Fourier transform infrared spectroscopy, ultraviolet‐visible spectroscopy, thermogravimetric analysis and scanning electron microscope. The mechanical properties of the nanofibrous mats were tested using universal testing machine. The wettability analysis was done using the contact angle measurement based on the sessile drop test. This study revealed that the electrospun PU/SPI‐based nanofibres are non‐sensitizing, non‐allergic and non‐toxic and that it can be used as a peculiar wound healing material.Inspec keywords: polymer fibres, nanofibres, nanomedicine, biomedical materials, wounds, electrospinning, zinc compounds, II‐VI semiconductors, wide band gap semiconductors, nanoparticles, nanofabrication, X‐ray diffraction, Fourier transform spectra, infrared spectra, ultraviolet spectra, visible spectra, thermal analysis, scanning electron microscopy, wetting, contact angle, toxicologyOther keywords: electrospun polyurethane nanofibres, soy protein nanofibres, wound dressing applications, electrospinning, nanofibre mat, soy protein isolate, zinc oxide nanoparticles, ciprofloxacin hydrochloride, X‐ray diffraction, Fourier transform infrared spectroscopy, ultraviolet‐visible spectroscopy, thermogravimetric analysis, scanning electron microscope, mechanical properties, universal testing machine, wettability, contact angle measurement, sessile drop test, nonsensitizing nanofibres, nonallergic nanofibres, nontoxic nanofibres, wound healing material, wavelength 300 nm to 350 nm, ZnO     

In<Subscript>2</Subscript>S<Subscript>3</Subscript> nanoparticles dispersed on g-C<Subscript>3</Subscript>N<Subscript>4</Subscript> nanosheets: role of heterojunctions in photoinduced charge transfer and photoelectrochemical and photocatalytic performance

Fast recombination of photogenerated charge carriers is a major problem in the photoelectrochemical and photocatalytic processes. In this work, we report significantly improved PEC performance of a nanocomposite consists of In₂S₃ nanoparticles dispersed on g-C₃N₄ nanosheets synthesized by a simple and facile wet chemical route. The results of high-resolution TEM study show that the obtained In₂S₃ nanoparticles of size 10–20 nm exist in cubic phase and are uniformly dispersed on the surface of g-C₃N₄ nanosheets. The In₂S₃/g-C₃N₄ nanocomposite with 25 weight percentage of In₂S₃ exhibits 8.5 times higher photocurrent density than the single-phase g-C₃N₄ under visible light illumination. The enhanced photocurrent density exhibited by the In₂S₃/g-C₃N₄ nanocomposite is attributed to the efficient separation of photogenerated charge carriers. The charge transfer mechanism in In₂S₃/g-C₃N₄ heterojunction was studied by a series of experiments, such as electrochemical impedance spectroscopy, photoelectrochemical measurement and photoluminescence emission spectroscopy. The intimate interface promotes the charge transfer and inhibits the recombination rate of photogenerated electron–hole pairs, which significantly improves the photoelectrochemical performance. A detailed charge transfer mechanism is discussed based on the Mott–Schottky plot study. This heterojunction material is found to be an efficient photocatalyst for the degradation of both cationic rhodamine B dye and anionic methyl orange dye as the lifetime of photogenerated charge carriers is higher in the composite than in single-phase In₂S₃ and g-C₃N₄. A strong correlation between the photoelectrochemical and the photocatalytic performances is observed in this composite.