Engineering and Applied Science Letters (EASL)

In this paper, finite difference method is used to study the combined effects of thermal radiation, inclined magnetic field and temperature-dependent internal heat generation on unsteady two-dimensional flow and heat transfer analysis of dissipative Casson-Carreau nanofluid over a stretching sheet embedded in a porous medium. In the study, kerosene is used as the base fluid which is embedded with the silver (Ag) and copper (Cu) nanoparticles. Also, effects of other pertinent parameters on the flow and heat transfer characteristics of the Casson-Carreau nanofluids are investigated and discussed. From the results, it is established that the temperature field and the thermal boundary layers of Ag-Kerosene nanofluid are highly effective when compared with the Cu-Kerosene nanofluid. Heat transfer rate is enhanced by increasing power-law index and unsteadiness parameter. Skin friction coefficient and local Nusselt number can be reduced by magnetic field parameter and they can be enhanced by increasing the aligned angle. Friction factor is depreciated and the rate of heat transfer increases by increasing the Weissenberg number. A very good agreement is established between the results of the present study and the previous results. The present analysis can help in expanding the understanding of the thermo-fluidic behaviour of the Casson-Carreau nanofluid over a stretching sheet.

The concept of vague graph was introduced early by Ramakrishna and substantial graph parameters on vague graphs were proposed such graph coloring, connectivity, dominating set, independent set, total dominating number and independent dominating number. In this paper, we introduce the concept of the dominator coloring and total dominator coloring of a vague graph and establish mathematical modelling for these problems.

This paper investigates the rotor and stator faults of synchronous and asynchronous machine. We studied major and minor faults and failures in synchronous and asynchronous machines (SAASMs) to avoid excessive downtime, maintaining quality of service, and minimum revenue losses to smart grid (SG) operators and planners. Further, faults detection, faults diagnosis, major causes of faults, and fault remedial measures are discussed with state-of-the-art work for: (a) transformers, (b) stator, and (c) rotor. Our work presents detailed taxonomy of rotor and stator faults, electrical and mechanical stress, and faults diagnosis schemes for stable SG operation. We believe that our research contribution is more versatile covering every aspect of SAASMs faults and failures, compared to prior works.

State Estimation is the backbone of modern electric power system and is used by almost all Energy Management Systems (EMS) in the world to ensure the real-time monitoring and secure operation of a power system. Phasor Measurement Unit (PMU) is most popular meter in today’s electrical power industry because of its high refresh rates and measurement accuracy. Meanwhile, state estimation with only PMUs is not practical because of the very high initial installation cost. Consequently, the use of PMU meters along with conventional Supervisory Control and Data Acquisition (SCADA) meters can improve the performance of the state estimation. In this paper, phasor measurements (voltage and current phasors) are incorporated in two robust estimators: Weighted Least Absolute Value (WLAV) and Least Measurement Rejected (LMR). Further, we have investigated the importance of locating PMUs to save cost and improve the performance of state estimation. The performance of these two estimators after incorporating voltage and current phasors is investigated in terms of estimation accuracy of state variables and computational efficiency in the presence of different bad-data scenarios on IEEE-30 and IEEE-118 bus systems.

Gas Metal Arc Welding (GMAW) is one of those welding processes which is increasingly being used in many varieties of fabrication and manufacturing industries due to high production rate and ease of work such as fewer fumes/smoke and less time chipping slag. Important parameters which affect GMAW process are amperage, arc length, wire feed speed, welding speed and welding voltage. In this paper, we have focused and studied important controllable factor’s effects on depth of penetration, deposition efficiency, bead width and bead reinforcement to find best weld during welding in mobile or outdoor welding shop in stress and overloaded conditions by Box-Behnken design of quadratic model for GMAW process and optimization analysis on desirability function. Quality of welds is defined as “the level of perfection that welds exhibit pertaining to the entire volume of weldment as well as to the profile of weld surface appearance”. With reference to quality weld definition as defined above, the study is performed to find out the best welding condition whereas best weld is the weld with deposition efficiency value as larger the best, depth of penetration value with “larger the best”, bead width value “nominal the best”, discontinuities number per weld’s count value “smaller the best”. Productivity in term of quality is defined as an optimum blend of parameters which inevitably develop minimum or no defect then the process will result in high productivity. For given certain material and similar welding circumstances, our analysis has found the most optimal factor’s values for the similar condition of field data. This study will contribute welding research work in terms of points as described, firstly to enhance the knowledge of welding process and analysis by utilizing DOE along with desirability function, secondly ability to provide narrow window of weld process parameter to produce the quality weld and thirdly to study the GMAW process for mobile welding shop in the toughest condition such as the windy and dusty environment.

Nanomaterials are compound substances or materials that are produced and utilized at an exceptionally little scale. Nanomaterials are created to display novel attributes contrasted with a similar material without nanoscale highlights, for example, expanded quality, synthetic reactivity or conductivity. Topological indices are numbers related to molecular graphs that catch symmetry of molecular structures and give it a scientific dialect to foresee properties, such as: boiling points, viscosity, the radius of gyrations and so on. In this paper, we aim to compute topological indices of \(TUC_4[m,n]\), \(TUZC_6[m,n]\), \(TUAC_6[m,n]\), \(SC_5C_7[p,q]\), \(NPHX[p,q]\), \(VC_5C_7[p,q]\) and \(HC_5C_7[p,q]\) nanotubes. We computed first and second K Banhatti indices, first and second K hyper-Banhatti indices and harmonic Banhatti indices of understudy nanotubes. We also computed multiplicative version of these indices. Our results can be applied in physics, chemical, material, and pharmaceutical engineering.

Multiple-input-multiple-output (MIMO) antennas performance can be degraded due to the poor isolation between the MIMO antenna elements. In this paper, we present a review of the different isolation enhancement schemes available in the literature. Empirically the isolation between the antennas can be improved by placing the antenna as far as possible and it can be enhanced further by introducing different isolation enhancement schemes. Theory of characteristic modes (TCM) was recently proposed that has useful benefits. TCM is also used to enhance the isolation. Moreover, this papers focus on the different approaches of TCM, to enhance the isolation.

In the fields of chemical graph theory (CGT), mathematical chemistry and molecular topology, a~topological index (TI) also known as a connectivity~index~is a type of a molecular descriptor that is calculated based on the molecular graph of a chemical compound. \(BiI_{3}\) is an excellent inorganic compound and is very useful in qualitative inorganic analysis and topological indices of \(BiI_{3} \) help to predict many properties like boiling point, heat of formation, strain energy, rigidity and fracture toughness and correlate the structure with various physical properties, chemical reactivity and biological activities. This paper computes several degree-based topological indices like multiplicative first Zagreb index, multiplicative second Zagreb index, multiplicative atomic bond connectivity index, multiplicative first and second hyper Zagreb index and multiplicative geometric arithmetic index for Bismuth Tri-Iodide chains and sheets.

Topological indices collect information from the graph of molecule and help to predict properties of underlined molecule. Zagreb indices are among the most studied topological indices due to its applications in chemistry. In this report we compute first and second reversed Zagreb indices and first and second reversed Hyper Zagreb indices for \(Si_{2}C_{3}I[r,s]\) and \(Si_{2}C_{3}II[r,s]\). Moreover we also compute first and second reversed Zagreb polynomials and first and second reversed Hyper Zagreb polynomials for \(Si_{2}C_{3}I[r,s]\) and \(Si_{2}C_{3}II[r,s]\).

Nicotiana tabacum is rich with medicinal importance. The aim of the study is to isolate, purify and compare nicotine (3-[1-Methylpyrolidine-2 yl] pyridine) from different brands of cigarettes. Isolation is carried out by liquid-liquid extraction using ether as solvent. Crude nicotine samples are further purified with SPE (solid phase extraction) method. Nicotine crystals are complexed with zinc chloride (\(ZnCl_{2}\)). Fine and pure crystals of metal complexes are obtained with Nic-C and Nic-D. However, no complex formation is synthesized with Nic A and Nic-B due to impurities in the sample which is confirmed by thin layer chromatography. Antibacterial activity of the samples is carried out against different strains of bacteria which showed positive results for Nic-C and Nic-D. The outcomes of the study reveal that Zinc-Nicotine complexes can be used as therapeutic agents and anti-sickness agents in sickle cell disease.