Characterization of Fe_3Si-based coatings on low silicon steel by pulsed Nd:YAG laser cladding

The Fe3Si based coating was produced on the Fe-1 Si steel surface by a pulsed Nd：YAG （yttrium aluminum garnet） laser. Its phase constitution and microstructure were characterized by using X-ray diffraction （XRD）, optical microscope （OM）, and field emission scanning electron microscope （FESEM） with associated energy dispersive spectroscopy （EDS） and transmission electron microscopy （TEM）. The hyperfine structure of the coating was studied by Mrssbauer spectra （MS） and the magnetic property was also measured at room temperature by a vibrating sample magnetometer （VSM）. The obtained coating is pore and crack-free with dense microstructure and high Si content. The metallurgical bonding between the coating and the substrate was realized. The microstructure of the coating is typical fine dendrites. The major phase was confirmed by XRD and TEM to be the ordering D03 structured Fe3Si phase. In addition, there were smaller amounts of the Fe5Si3 phase and the γ-Fe phase in the coating. Compared with the substrate, the laser cladding coating has a lower saturation magnetization and a higher coercive force. The poor magnetic property might be because of rapid solidification microstructure and phase constitution in the coating.

Differences and Similarities of Photocatalysis and Electrocatalysis in Two-Dimensional Nanomaterials:Strategies,Traps,Applications and Challenges

Photocatalysis and electrocatalysis have been essential parts of electrochemical processes for over half a century.Recent progress in the controllable synthesis of 2D nanomaterials has exhibited enhanced catalytic performance compared to bulk materials.This has led to significant interest in the exploitation of 2D nanomaterials for catalysis.There have been a variety of excellent reviews on 2D nanomaterials for catalysis,but related issues of differences and similarities between photocatalysis and electrocatalysis in 2D nanomaterials are still vacant.Here,we provide a comprehensive overview on the differences and similarities of photocatalysis and electrocatalysis in the latest 2D nanomaterials.Strategies and traps for performance enhancement of 2D nanocatalysts are highlighted,which point out the differences and similarities of series issues for photocatalysis and electrocatalysis.In addition,2D nanocatalysts and their catalytic applications are discussed.Finally,opportunities,challenges and development directions for 2D nanocatalysts are described.The intention of this review is to inspire and direct interest in this research realm for the creation of future 2D nanomaterials for photocatalysis and electrocatalysis.

A Brief Review of How to Construct an Enzyme-Based H₂O₂Sensor Involved in Nanomaterials

This article briefly reviews how to construct an enzyme based hydrogen peroxide sensor involving nanomaterials, which has the advantages of high efficiency, good sensitivity and selectivity, fast response time and an extended range of linearity with lower detection limit. Glucose biosensor is constructed by immobilizing glucose oxidase enzyme on the polycarbonate membrane and the protective cover is then filled with a physiological phosphate buffer, pH 7.4. The novel blocking hydrophobic membrane which is only permeable to hydrogen peroxide is used to eliminate electrochemical interferences. This constructed enzyme based H2O2 biosensor is miniaturized by the involvement of nanomaterials like carbon nanotubes, platinum nanoparticles and silver nanoparticles and it can achieve the effective microscopic detection of glucose. The introduction of nanomaterials including some pure metals (Ag, Au, Pd, Ni, Pt, and Cu), metal oxide (ZnO and TiO2), bimetallic (Au/Ag and Au/Pt) and carbon (nanotubes and graphene) nanomaterials in the construction of the enzyme based H2O2 biosensor improves its sensitivity and performance by enhancing the enzymatic activity, and allows the introduction of many new signal transduction technologies in biosensors. This review article summarizes the working principles of glucose oxidase based hydrogen peroxide sensor, importance of involving nanomaterials in biosensor manufacturing, basic characteristics and components of a biosensor, generations glucose biosensors, procedure of making hydrogen peroxide based biosensor, synthesis of nanomaterials involved in hydrogen peroxide biosensor, and finally some examples of nanomaterials which intervene in hydrogen peroxide biosensor.

Simplified Mathematical Model of Glucose-Insulin System

Mathematical modelling of glucose-insulin system is very important in medicine as a necessary tool to understand the homeostatic control of human body. It can also be used to design clinical trials and in the evaluation of the diabetes prevention. In the last three decades so much work has been done in this direction. One of the most notable models is the global six compartment-mathematical model with 22 ordinary differential equations due to John Thomas Sorensen. This paper proposes a more simplified three compartment-mathematical model with only 6 ordinary differential equations by introducing a tissue compartment comprising kidney, gut, brain and periphery. For model parameter identification, we use inverse problems technique to solve a specific optimal control problem where data are obtained by solving the global model of John Thomas Sorensen. Numerical results show that the proposed model is adaptable to data and can be used to adjust diabetes mellitus type I or type II for diabetic patients.

Global Stability of a SVEIR Epidemic Model: Application to Poliomyelitis Transmission Dynamics

The lack of treatment for poliomyelitis doing that only means of preventing is immunization with live oral polio vaccine (OPV) or/and inactivated polio vaccine (IPV). Poliomyelitis is a very contagious viral infection caused by poliovirus. Children are principally attacked. In this paper, we assess the impact of vaccination in the control of spread of poliomyelitis via a deterministic SVEIR (Susceptible-Vaccinated-Latent-Infectious-Removed) model of infectious disease transmission, where vaccinated individuals are also susceptible, although to a lesser degree. Using Lyapunov-Lasalle methods, we prove the global asymptotic stability of the unique endemic equilibrium whenever ?. Numerical simulations, using poliomyelitis data from Cameroon, are conducted to approve analytic results and to show the importance of vaccinate coverage in the control of disease spread.

Electrical and thermal performances of photovoltaic/thermal systems with magnetic nanofluids:A review

Enhancing solar photovoltaic and thermal conversion performances may help develop more environmentally friendly hybrid photovoltaic/thermal(PV/T)systems that can be used in applications ranging from household to industrial scales.Owing to their enhanced thermal and optical properties,nanofluids have proven to be good candidates for designing PV/T systems with superior performances.As smart nanofluids,magnetic nanofluids(MNFs)can further enhance the performances of PV/T systems under external magnetic fields.This paper reviews recent developments in enhancing the electrical and thermal performances of PV/T systems using magnetic nanofluids.Various parameters affecting the performances are highlighted,and some areas for further investigations are discussed.The reviewed literature shows that PV/T systems with MNFs are promising.However,their performances need further investigation before they can be used in applications.

Machine learning property prediction for organic photovoltaic devices

Organic photovoltaic(OPV)materials are promising candidates for cheap,printable solar cells.However,there are a very large number of potential donors and acceptors,making selection of the best materials difficult.Here,we show that machine-learning approaches can leverage computationally expensive DFT calculations to estimate important OPV materials properties quickly and accurately.We generate quantitative relationships between simple and interpretable chemical signature and one-hot descriptors and OPV power conversion efficiency(PCE),open circuit potential(Voc),short circuit density(Jsc),highest occupied molecular orbital(HOMO)energy,lowest unoccupied molecular orbital(LUMO)energy,and the HOMO–LUMO gap.The most robust and predictive models could predict PCE(computed by DFT)with a standard error of±0.5 for percentage PCE for both the training and test set.This model is useful for pre-screening potential donor and acceptor materials for OPV applications,accelerating design of these devices for green energy applications.

Imidazolium-based ionic liquids as additives to preserve the Enhanced Green Fluorescent Protein fluorescent activity

Fluorescent Proteins(FP)can be applied as biomarkers and biosensors in the industrial and medical fields,but their large-scale use,especially for new industrial applications,is limited due to their low stability.Hence,the discovery of additives capable of preserving the activity of FP at room temperature and under stress conditions can help to expand and facilitate their commercial use.With this goal,we evaluated the application of 1-alkyl-3-methylimidazolium chloride-based([C_(n)mim]Cl)ionic liquids(ILs)as additives to preserve the activity of Enhanced Green Fluorescent Protein(EGFP)at different storage times and under unfavorable conditions.All[C_(n)mim]Cl solutions(at 0.100 mol L^(-1))were able to preserve EGFP fluorescence for longer than the phosphatesaline buffer(PBS)and NaCl solutions,increasing its fluorescence manifestation from 1 to 3 months.[C_(n)mim]Cl with shorter to medium cationic alkyl chains were the most effective in preserving EGFP fluorescence.[C_(n)mim]Cl also protected EGFP activity in the presence of the surfactant SDS,the acid guanidine hydrochloride,and H_(2)O_(2).Therefore,[C_(n)mim]Cl can be added to aqueous solutions to preserve EGFP fluorescence activity at room temperature for longer storage times and to reduce the negative impact of denaturing agents on EGFP.Therefore,there is a massive potential for the application of ILs as additives to preserve FP in the long-term without refrigeration and under unfavorable conditions,and this is fundamental to enable expansion of FP in industrial and commercial applications.