Review: Machine learning techniques in analog/RF integrated circuit design,synthesis, layout,and test

Rapid developments in semiconductor technology have substantially increased the computational capability of computers. As a result of this and recent developments in theory, machine learning (ML) techniques have become attractive in many new applications. This trend has also inspired researchers working on integrated circuit (IC) design and optimization. ML-based design approaches have gained importance to challenge/aid conventional design methods since they can be employed at different design levels, from modeling to test, to learn any nonlinear input-output relationship of any analog and radio frequency (RF) device or circuit; thus, providing fast and accurate responses to the task that they have learned. Furthermore, employment of ML techniques in analog/RF electronic design automation (EDA) tools boosts the performance of such tools. In this paper, we summarize the recent research and present a comprehensive review on ML techniques for analog/RF circuit modeling, design, synthesis, layout, and test.     

Electrospun nanofibers as a platform for multifunctional,hierarchically organized nanocomposite

Nanofibers are ideally suited to form a scaffold where multi-functional components can be hierarchically organized. Development in electrospinning in terms of fiber construction and organization, materials selection and incorporation, and post-spinning modifications have pathed the way for future developments of advanced composite systems. A nanocomposite system with up to five distinct levels of organization can be constructed using electrospun fibers. At the first level is a composite nanofiber. The second level is a second layer of composite material coated over the core composite nanofiber. Surface modification of the nanofiber will give the third level. The fourth level of organization is by arranging the nanofibers to form an assembly. Finally at the last level, the nanofiber assembly can be encapsulated within a matrix or form a bulk structure of a pre-determined shape. Examples of how hierarchically organized multifunctional nanocomposite can be used in healthcare, environmental and defense and security is discussed.     

Diversity of bacteriocins produced by lactic acid bacteria isolated from raw milk

Bacteriocin-producing lactic acid bacteria were isolated from 298 samples of raw ewes', goats’ or cows’ milk. Eighty-two bacteriocin producers were phenotypically and genotypically identified as L. lactis subsp. lactis (59 isolates), L. lactis subsp. cremoris (2 isolates), L. lactis subsp. lactis biovar diacetylactis (6 isolates), E. faecalis (7 isolates), E. faecium (1 isolate), L. paracasei subsp. paracasei (4 isolates), L. plantarum (1 isolate) and Leuconostoc spp. (2 isolates). By means of PCR-techniques, nisin was characterized in 39 of the 67 bacteriocin-producing lactococci and lacticin 481 in 23 isolates, some of which presented antilisterial activity. Enterocin AS-48 was produced by four enterococcal isolates. Four non-identified bacteriocins produced by 16 isolates showed a broad inhibitory spectrum. Nisin-producing lactic acid bacteria were the most abundant, but lacticin 481-producing lactococci and AS-48-producing enterococci were found at relatively high rates.     

Photocatalytic degradation of ciprofloxacin pollutant and in-vitro cytotoxic activity of gold nanoparticles using seed extract of Abrus precatorius

Synthesis of nanoparticles from plant extract is a very simple reliable, rapid, affordable and un-hazardous technique. In the present exploration, gold nanoparticles (Au NPs) were rapidly synthesized using seed extract of Abrus precatorius. The prepared nanomaterials were systematically proved by FTIR, UV–Visible, Powder-XRD, SEM, EDAX and TEM analyses. The formation of Au NPs was primarily identified by the colour change from yellow to purple within 5 min and which showed a surface Plasmon peak around 535 nm. The dimension of the gold nanoparticles was found to be in the range of 10–20 nm. The particles were poly-dispersed with a triangular, spherical and hexagonal shape. The gold nanoparticles were used to degrade the antibiotic drug ciprofloxacin (CIP) with an efficiency of above 95%. Moreover, the bio-synthesized gold nanoparticles had been assessed for their in-vitro cytotoxic activity on human breast cancer cells (MCF-7) lines. The colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was used to evaluate the Inhibitory Concentration (IC₅₀) value. The IC₅₀ value is 37?±?1.5 µg/mL. In future, this can be used for breast cancer therapy.

     

Steady and unsteady flow characteristics of dual cavity in strut injection scramjet combustor

This study aims to understand the flow performance of a dual wall-mounted cavities in a strut-injector mounted scramjet combustor for steady-state and transient reacting conditions. Conventionally, two-dimensional Reynolds Averaged Navier-Stokes approach is adopted to compute the steady flow, whereas the current research employs Delayed Detached Eddy Simulation for predicting the unsteady flow characteristics as well. The calculated flow patterns, density, pressure, and temperature fields of dual cavities are compared with shadowgraph and wall pressure measurements from DLR experiments. The dual cavities position substantiates to explore the interplay between wave propagation and shear layer mixing characteristics. Employing a dual cavities arrangement accelerates toward the complete combustion relative to the baseline model. The combustion zone widens in the lateral direction as the dual cavities shift the shock train downstream of the strut injector owing to intense shock shear layer interactions. These cavities' existence significantly modifies the dominating frequencies and affects the strength of the diverging section's coherent flow structures.     

Studies on extreme pressure films — reactions of sulphurized vegetable oils and alkyl phenols with iron

The reaction products of sulphurized Mohwa oil and sulphurized pentadecyl phenol (hydrogenated cardanol) with iron powder in hydrocarbon medium at 150°C for 8 h were studied to investigate the type of lubricant films formed during their application as antiwear and extreme pressure additives. Three main reaction products were isolated on the basis of their solubilities in chloroform and dimethyl formamide. An examination of their elemental analysis and infrared absorption data reveals that there is progressive reduction in the length of the alkyl chains and carbonyl ester group in the case of sulphurized Mohwa oil, with subsequent formation of inorganic iron sulphides, on the one hand, and polymerized products with a number of ketonic and aldehydic groups containing iron and sulphur in the polymeric films, in the form of unsaturated cyclic rings. The alkyl phenol, on similar studies, gave polymerized products with elimination of the long alkyl chain and containing cyclized rings with sulphur present in the form of sulphide bridges and in the heterocyclic ring structures, with progressive elimination of iron as iron sulphide. The films formed are organo-inorganic in nature, rather than the purely inorganic iron sulphide type. The load-carrying characteristics of these products are strongly influenced by the type of the film formed on the iron surfaces.     

Mathematical modelling of the biofiltration treating mixtures of toluene and N-propanol in the biofilm and gas phase

This paper presents a mathematical model in the biofilm phase and in the gas phase that has been successfully applied to investigate various aspects of the biofiltration process. The mixtures of volatile organic compounds (VOCs) are emitted from a wide range of industries, such as chemical, petrochemical, pharmaceutical, pulp paper mills, printing and paint workshops, etc. The objective of the present study is, presence of high n-propanol loading negatively affected the toluene removal; however, n-propanol removal was not affected by the presence of toluene and was effectively removed in the biofilter despite high toluene loadings. A model for toluene and n-propanol biofiltration could predict the cross-inhibition effect of n-propanol on toluene removal. Further, we studied the effects of many physical and biological parameters on model prediction. The mathematical equations (2.12)-(2.16) which are non-linear partial differential equations are solved by using the homotopy perturbation technique. Also, we derived the semi-analytical results for toluene and n -propanol concentrations for saturated and unsaturated kinetics. It is verified that the proposed solution is validated by comparing it with numerical solutions.     

Diffusion combustion of microjets modulated by dean vortices

The paper presents the results of experimental investigation of circular jets forming as the Dean vortices modulate them at the curved channel exit. Some features of the jet flow are analyzed under the conditions of interaction between the Dean vortices and the Kelvin-Helmholtz ring vortices which results in the jet evolution different from that observed as the jet is generated behind circular and flat nozzles at the straight channel exit. In turn, the variations in the flow structure influence the regime of the diffusion jet combustion. The effect of Dean vortices on combustion of hydrogen and its mixture with oxygen and that of propane is analyzed in this paper. Flame transformation under forcing of external acoustic waves at a proper frequency stimulating flow instability is discussed.     

Development of a Ru catalyst supported on HY zeolite for the oxidative decomposition of NH3 triggered at room temperature

On-site hydrogen production from the oxidative decomposition of NH₃ with a catalyst is highly required in the countryside where external heat is hardly supplied. In this study, Ru-based zeolite catalysts were prepared by impregnation and subsequent washing using RuCl₃·3H₂O and HY zeolite or H-MOR zeolite for the oxidative decomposition of NH₃. The H-MOR-supported Ru catalyst could not be self-heated by feeding 80% NH₃/20% O₂ to the catalyst bed at room temperature. By contrast, the HY-supported Ru catalyst underwent self-heating to approximately 773 K upon feeding the reactants owing to the heat released by NH₃ adsorption and oxidation, leading to excellent performance for the oxidative decomposition of NH₃ during five cycles of start-up tests. Characterization results indicated that the Cl-free Ru/HY catalyst exhibited self-heating due to the presence of small well-dispersed Ru metal particles and a large amount of surface acidic sites.