Reliable computation of solid solubility in dense gases through homotopy continuation approach

A method to reliably compute the solid solubility in supercritical fluids is described. The method is based on computing all the possible roots of equifugacity equation at given temperature and pressure through homotopy continuation. The equifugacity equation is reformulated through global fixed-point homotopy. The global fixed-point homotopy guarantees that all the solutions of a non-linear equation can be located on a single homotopy path when it is forced to start from a single starting point. The starting point is selected from a criterion which minimizes the number of real roots of the global fixed-point homotopy function. Homotopy continuation-based formulation of equifugacity equation is also used to directly generate the solubility-pressure and solubility-temperature bifurcation diagrams by selecting either pressure or temperature as continuation parameter. These bifurcation diagrams provide a direct pathway to locate the cross-over pressures. The effect of equation of state model parameters on solid solubility through homotopy continuation based sensitivity analysis is also analyzed. Peng Robinson Stryjek Vera equation of state with conventional and Wong-Sandler mixing rules are used.     

Electrochemical fabrication of self assembled monolayer using ferrocene-functionalized gold nanoparticles on glassy carbon electrode

Electrochemical (EC) quantification of 11-Mercaptoundecylferrocene (thiolated-ferrocene substrate, Fc-SH) onto gold nanoparticles (AuNPs) was carried out through cyclic voltammetric (CV) investigations in different base electrolyte aqueous media on glassy carbon (GC) electrode. The electrochemical data including peak current, peak potential values revealed the Fc-SH–AuNPs redox system to be adsorption controlled in terms of self assembled monolayers (SAMs). The electrochemically generated SAMs were found quite stable as these maintained the redox activity upto 3 months after repeated CV scans at 298 K. The overall output of this research can be utilized in two ways: application of electroactivity and stability of these SAMs in detection of biologically important molecules and also towards the development of EC biosensors.     

A potential electrolyte (Ce1-x CaxO2-δ) for fuel cells:Theoretical and experimental study

First-principles calculations are performed using density function theory to explore the effects of dopant Ca in ceria (Ce_1-xCa_xO_2-δ). The impact of oxygen vacancy on band gap and density of states is examined in doped ceria using generalized gradient approximations. Vacancy association and vacancy formation energies of the doped ceria are calculated to reveal the effect of dopant on ion conduction. The experimental study of the sample (Ce_0.875Ca_0.125O_2-δ) was performed to compare with the theoretical results. The obtained results from theoretical calculation and experimental techniques show that oxygen vacancy increases the volume, lattice constant (5.47315?Å) but decrease the band gap (1.72?eV) and bulk modulus. The dopant radius (1.173?Å) and lattice constant (5.4718?Å) are also calculated by equations which is close to the DFT lattice parameter. The result shows that oxygen vacancy shifts the density of states to lower energy region. Band gap is decreased due to shifting of valence states to conduction band. Vacancy formation shows a significance increase in density of states near the Fermi level. Density of states at Fermi level is proportional to the conductivity, so an increase in density of states near the Fermi level increases the conductivity. The experimental measured ionic conductivity is found to 0.095?S?cm^?1 at 600?°C. The microstructural studies is also reported in this work.     

Cloud‐based decision support system for the detection and classification of malignant cells in breast cancer using breast cytology images

The advancement of computer‐ and internet‐based technologies has transformed the nature of services in healthcare by using mobile devices in conjunction with cloud computing. The classical phenomenon of patient–doctor diagnostics is extended to a more robust advanced concept of E‐health, where remote online/offline treatment and diagnostics can be performed. In this article, we propose a framework which incorporates a cloud‐based decision support system for the detection and classification of malignant cells in breast cancer, while using breast cytology images. In the proposed approach, shape‐based features are used for the detection of tumor cells. Furthermore, these features are used for the classification of cells into malignant and benign categories using Naive Bayesian and Artificial Neural Network. Moreover, an important phase addressed in the proposed framework is the grading of the affected cells, which could help in grade level necessary medical procedures for patients during the diagnostic process. For demonstrating the e effectiveness of the proposed approach, experiments are performed on real data sets comprising of patients data, which has been collected from the pathology department of Lady Reading Hospital of Pakistan. Moreover, a cross‐validation technique has been performed for the evaluation of the classification accuracy, which shows performance accuracy of 98% as compared to physical methods used by a pathologist for the detection and classification of the malignant cell. Experimental results show that the proposed approach has significantly improved the detection and classification of the malignant cells in breast cytology images.     

Rouleaux red blood cells splitting in microscopic thin blood smear images via local maxima,circles drawing,and mapping with original RBCs

Splitting the rouleaux RBCs from single RBCs and its further subdivision is a challenging area in computer‐assisted diagnosis of blood. This phenomenon is applied in complete blood count, anemia, leukemia, and malaria tests. Several automated techniques are reported in the state of art for this task but face either under or over splitting problems. The current research presents a novel approach to split Rouleaux red blood cells (chains of RBCs) precisely, which are frequently observed in the thin blood smear images. Accordingly, this research address the rouleaux splitting problem in a realistic, efficient and automated way by considering the distance transform and local maxima of the rouleaux RBCs. Rouleaux RBCs are splitted by taking their local maxima as the centres to draw circles by mid‐point circle algorithm. The resulting circles are further mapped with single RBC in Rouleaux to preserve its original shape. The results of the proposed approach on standard data set are presented and analyzed statistically by achieving an average recall of 0.059, an average precision of 0.067 and F‐measure 0.063 are achieved through ground truth with visual inspection.     

Influence of the Erodent Shape on the Erosion Behavior of Ductile and Brittle Materials

Solid particle erosion is identified as a major wear process occurring in numerous industrial applications. A number of test parameters influence the behavior of the materials during this wear process. Particle shape is one of the key factors, which is often discussed for ductile or brittle materials in the literature, but a comparative study of ductile and brittle materials showing an effect of particle shape has not been addressed in detail until now. The present work discusses the influence of erodent shape on the wear behavior of a ductile (Ti-6Al-4 V alloy) and a brittle (TiN coating) material during the erosion process. Investigations are performed in an erosion test rig where the ductile and brittle materials are charged with spherical and angular SiO₂ particles at normal impact. Results show an inverse erosion behavior of ductile and brittle materials with the variation in particle shape. Ductile materials show low material removal with spherical particles, whereas brittle materials show low material removal rates with angular ones. This work also provides an analysis of the material removal phenomenon to understand the effect of particle shape on tested materials. Since materials removal phenomenon in ductile materials is often reported in the literature, this work addresses the material removal behavior especially in ceramic coatings.     

Probabilistic approach for estimating heat fluid exit temperature correlation in a linear parabolic trough solar collector

This paper demonstrates a probabilistic modelling approach for establishing the correlation of Heat transfer fluid (HTF) temperature, obtained at the exit of a linear Parabolic trough collector (PTC). For the purpose, an analytical heat transfer (Physical) model was developed and validated by comparing its result with the published values. The correlation was then fitted on a dataset obtained by simulating this physical model over the sampled values acquired by applying the Latin hypercube sampling (LHS) technique over a realistic distribution of factors. The preliminary correlation was based on twenty-six natural, design and operational factors, including normal solar radiation, HTF flow rate, ambient conditions and different attributes associated with geometry and material of the concentrating reflector, receiver, sleeve and selective coating. The coefficient of determination (R²) for correlation was 98.4 %. After analyzing the significance of each factor, a simplified correlation was proposed with only nine factors. The applications associated with this work include the design and simulation of direct and indirect steam generation systems, solar-assisted power generation, space heating, cooling, refrigeration and desalination.

     

Current challenges in hydrate-based desalination: Kinetic and thermodynamic perspective

Water scarcity is becoming a severe problem worldwide due to inadequate freshwater resources and swift population growth. Seawater desalination is one of the vital approaches to meet the demand for freshwater. However, energy and associated costs with conventional seawater desalination techniques are incentivizing non-conventional water desalination processes. Water desalination using gas hydrates formation is one of the emerging non-conventional processes. In this perspective article, recent advances in hydrate-based seawater desalination (HBSD) have been critically analyzed to outline a future path towards a clean and efficient hydrate-based desalination process. It provides a detailed comparison of various processes developed over decades, and measured desalination efficiencies with their process details. Moreover, the current challenges, limitations, and future perspectives of hydrate-based desalination are also discussed. The study also recapitulates the thermodynamics and kinetics aspects of the hydrate-based desalination process. In addition, various factors controlling the desalination efficiencies, such as control of the separation of hydrate crystals, salt deposition on hydrate particles, and hydrate morphology, were thoroughly investigated with their proposed process designs. The kinetics of hydrate formation is also assessed, with the possibility of a zero-induction regime and its consequent impact on hydrate morphology. The current capabilities of the thermodynamics models (Gibbs energy minimization + electrolyte equation of state) were discussed using various commercially available software. Additionally, the role of hydrate promotors is also discussed, which can reduce the higher cost associated with the hydrate-based desalination process.     

Antibacterial PES/Vancomycin ultrafiltration membranes with enhanced water flux and low BSA rejection

Polyethersulfone (PES) blended with glycopeptide Vancomycin was fabricated via phase inversion method. The fabricated membranes were characterized by scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), contact angle (CA) and optical profilometry. The PES/Vancomycin membranes showed a notable increase in hydrophilicity, porosity, pore size, antibacterial activity and water flux in comparison with pristine membranes. The changes are due to the hydrophilic nature of Vancomycin molecules and ability to form hydrogen bond quickly. The surface hydrophilicity of PES/Vancomycin membranes decreased up to 48° with increase in surface roughness (R_a), that is, 0.347 μm, thus increasing the water flux of PES/Vancomycin membranes up to 340 L/m². h. The bovine serum albumin (BSA) rejection decreases, that is, pristine 70.9% to PES/Vancomycin 26% and BSA flux increases at constant ionic strength (0.1) and above the isoelectric point (IEP) of the BSA. Under these conditions, electrostatic interactions are expected to be minimum between protein and the membrane surfaces.     

Comparative Analysis of Bio-Inspired Algorithms for Underwater Wireless Sensor Networks

Wireless Personal Communications - Mobile nodes in underwater wireless sensor networks are becoming very important as they not only enable flexible sensing areas but also entails the ability to...