Multi Step Research Articles

Investigation of electrochemical performance of the biosynthesized α-Fe2O3 nanorods

This study concerns with the development of a facile method for the biosynthesis of α-Fe2O3 nanorods through green method with an extract from Persea Americana seeds and the potential use of these nanords in the electrochemical applications. The α-Fe2O3 biosynthesized with an extract from Persea Americana seeds thereby was studied by the means of X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectroscopy (EDS), Ultraviolet–Visible (UV–vis) analysis, Fourier Transform Infra-Red (FT-IR) spectroscopy, Mössbauer spectroscopy and Cyclic voltammetry. X-ray diffraction (XRD) pattern of the sample determined the crystal structure of α-Fe2O3 nanorods. Transmission Electron Microscopy (TEM) measurements showed a nanorod-based morphology with average diameter of 50 nm and length of 400 nm. FTIR spectrospy spectrum confirmed the phase purity and chemical bond for the sample. The energy band gap Eg value obtained for α-Fe2O3 nanorods based on UV vis spectrum was 2.7 eV. Mössbauer results confirmed the weak ferromagnetic behaviour of the sample as well as the oxidization state. Cyclic voltammetry measurements of α-Fe2O3 nanorods sample coated on glassy carbon electrode (GCE) showed two oxidation peaks at 0.62 V and 0.88 V associated with reversible multi step oxidation of Fe to FeO and then Fe2O3. Electrochemical impedance spectroscopy studies revealed minimum charge transfer resistance Rct value, suggesting that α-Fe2O3 nanorods prepared has good conductivity and can be used in electrochemical energy storage application.

Novel functional brain network methods based on CNN with an application in proficiency evaluation

With the advancements in the research about the EEG signal processing, there are a large number of different analytical methods include the functional brain network (FBN) methods, most of them are unsupervised and need multi handcrafted steps until classification. It is expected to propose a general-purpose method based on deep learning methods to improve the situation. Therefore, in this paper, we proposed two methods based on the convolutional neural network (CNN). One was analyzing adjacent matrixes computed by the phase locking value (PLV) to generate features based on CNN, which was equivalent to the graph-theoretic (GT) indexes functionally. The other method was a novel end-to-end method, brain connection based on CNN (BCCNN), which used a factorized 1-D CNN to filter the temporal part of the raw EEG, computed the correlation coefficients among the electrodes to build a new kind of FBNs and then extracted features from the FBNs like the last method. Then we performed a working memory (WM) experiment to verify the validity of the two methods. Those methods were used to detect the proficiency of the subjects in a WM task. In the results, the accuracy of the first method was 99.33%, which was as good as that of the GT indexes (99.35%). The accuracy of the second methods was 96.53%, which was lower than the performance of the PLV but higher than that of two conventional CNNs (94.37%, 90.83%).

RESTRUCTURE AS A PROPOSED APPROACH FOR IMPROVING FINANCIAL PERFORMANCE IN THE MAIN BANK FOR DEVELOPMENT AND AGRICULTURAL CREDIT FROM AN ENVIRONMENTAL PERSPECTIVE

The banking reformation program adopted by Egyptian banks and supported by the state’s powers drives at reinforcing its validity and credibility, so, the Egyptian Agricultural Bank (Ex-Development and Agricultural Credit) in order to go through this experience, by this a good internal and external reputation under the environment Law no. (4), of 1994 and revised by Law no. (9), of 2009. The restructure processes are targeting a procedure of necessary correction of technical, economic, and financial structures of an organization from an environmental perspective in a way that enables banks to survive in business world. In Light of the research and expected implementation of the process of restoring the financial structure, a comparative analytical study is conducted to measure the effect of some problems affecting the banking performance as a basis for reaching a proposed accounting framework to restore the financial structure from the environmental perspective, the research is based on the use of SPSS method by determining the T test F test as well as the use of quantitative analytical descriptive method based on the design and application of simple and multi–step regression model to reach the results. The research includes two types of variables: the independent variable is the restructuring of the financial structure – the control and administrative restrictions – the sovereign declarations – the efficiency of the work – the efficiency of the productivity and the dependent variable includes the maximization of profitability and derived from it (reducing costs – improving efficiency performance – maximizing profits- incentives- System of Credit and Marketing). This research recommends that banks in general, and the Egyptian Agricultural Bank in particular should focus and optimal utilization of resources and available opportunities; focusing as well on the relative advantage of the bank, as it becomes the launching point using modern technology.

Developing Country Teenagers’ Consumption Related Cognition Through Involvement in Television Commercial (Tvc): A Multi-item Measurement Scale

The core intention of the researchers is to develop and confirm a multi-item measurement scale for consumption related cognition through teenagers’ involvement in Television Commercial (TVC) of developing country like Bangladesh. Another important purpose of this research is to understand the influence of TV advertisements on consumption related cognition of developing countries’ teenagers. Very limited research has been conducted on consumption related cognition through involvement of TVC, even though it is the fundamental step which activates any consumers’ — especially teenagers’ — buying stimuli. Among the limited ones conducted, most of the research work has focused on scale items, such as product knowledge, consumer perception, purchasing intention, brand perception and product usage without providing any importance to complex variable or factors of consumption related cognition from which the scale items derive. Hence, an elaborated multi step research method has been used to find out and refine both the complex and simple variables of consumption related cognition through TVC involvement. Research findings have been statistically verified using exploratory and confirmatory factor analysis techniques. This research has revealed six main complex variables or factors namely consumption related- cognitive awareness, cognitive knowledge, cognitive mapping, cognitive linkage, cognitive complexity and cognitive skills. Four to five multi item measurement scales have been derived from each of the six factors.

Synthesis of two A-B-C type conjugated amphiphilic triblock fullerene derivatives and their application in organic solar cells

Two A-B-C type conjugated amphiphilic triblock fullerene derivatives C60-2HMTPB and C60-2EHTPB were obtained in multi steps synthesis with three different blocks, and the amphiphilic diblock molecular C60-4TPB was also preferred as a reference. When as modifying layer on zinc oxide (ZnO), the three fullerene derivatives can all reduce the work function of ZnO via modulation of the interfacial dipoles and lead a better electrical coupling. As introducing treatment of toluene, the obvious self-assembly of fullerene derivatives were observed, which were supported by X-ray diffraction and contact angle of water measurement. Base on PTB7-Th:PC71BM system, the inverted organic solar cells devices with structure of ITO/ZnO/fullerene derivatives/PTB7-Th:PC71BM/MoO3/Al got power conversion efficiencies of 8.62%, 8.83% and 9.00% for C60-4TPB, C60-2HMTPB and C60-2EHTPB, respectively, compared 8.13% of devices with bare ZnO. The result of conjugated amphiphilic triblock fullerene derivatives provides a straightforward approaching by simultaneously modulating the morphology and interfacial work function of ZnO, which can also lead high performance in optoelectronic devices.

CuNCo3-Xvx Antiperovskite As a High Performance Catalyst for Oxygen Evolution Reaction

Oxygen evolution reaction (OER) has drawn particular attention due to its important role for various energy generation and storage application, such as water splitting, rechargeable metal-air batteries and regenerative fuel cells. However, the intrinsically sluggish kinetic caused by multi proton-couple electron transfer steps, makes the OER inefficient on these applications. To promote the overall energy storage and generative efficiency, it is indispensable to develop highly efficient electrocatalyst for OER. Up to now, the noble-metal oxides (e.g. IrO2 and RuO2) are still considered as the best electrocatalysts for OER. Nevertheless, the high cost and scarcity of the involved precious metal have greatly limited their applications. Therefore, it urgently requires to seek the highly efficient OER catalysts that are cost-effective and earth-abundant. In the past decades, the perovskite oxides (ABO3, where A is rare or alkaline earth metal element and B is transition metal element) have been considered as an alternative OER catalyst for their low cost and intrinsically desirable OER activities. These oxides possess sufficient combination between different transition metal, which enables the highly synergic effect for their electrocatalysis. Also, the A site or B site can be partially substituted by other transition metal. This structural flexibility can arise the enhancement of the activity and stability of the perovskite oxides. However, the perovskite-based OER catalysts usually suffer poor conductivity at the applied temperature. To solve this problem, a widely used strategy is to combine metal oxides with high-surface-area carbon supports. It’s notable that metal oxide/carbon hybrid catalysts are unstable, especially under the condition of oxygen evolution reaction, because the oxidation of carbon occurs at low potentials (equilibrium potential of 0.207 V vs. the reversible hydrogen electrode (RHE). Transition metal nitrides are very attractive as robust supports and electrocatalysts because they have a number of desirable properties such as high electrical conductivity. Some antiperovskite nitride such as InNNi3 have been considered as the superconductive materials. More interestingly, the antiperovskite nitrides (ANM3, A and M represent different transition metal, respectively) share the similar perovskite structure with the perovskite oxides. Moreover, the perovskite structure of antiperovskite nitrides may enable the ANM3 to achieve structural flexibility as the corresponding effects have been verified by the previously reported materials (e.g. CdNCo3-zNiz (0  z 3) and Cd1−xInxNNi3 (0  x  0.2)). The tunable structure of the ANCo3 can offer much potential for the optimization of its electrocatalytic activity. Herein, we report an antiperovskite-based CuNCo3-xVx (0  x < 1) nitride as a high-performance OER catalyst exhibiting favorable electrocatalytic activity and stability. The experimental results reveal that the CuNCo3 exhibits highly intrinsic OER performance compared to Co4N. And the structural flexibility of the antiperovskite CuNCo3 also has been verified by the partially substituting the Co sites with V. The derived CuNCo2.4V0.6 can achieve an impressive enhancement with an overpotential of merely 242 mV to reach the current density of 10 mA cm-2. The time-dependent potential measurement and zinc-air batteries test also suggested its superior durability compared to Ir/C catalyst. Density of states (DOS) indicates the partial substitution of Co by V results in the negative shift of the d band center near the Fermi level for CuNCo3, which would weaken the interaction between the adsorbates and the OER catalyst and facilitate the OER process.

Advanced Authentication System

Advanced authentication system (AAS) is a new way of using password where user doesn’t need to remember complex text based passwords. In most of the important web-portals such as banking or data-management, the authentication process consists of textual passwords which is prone to many security attacks such as brute-force, keylogging, dictionary attack, shoulder surfing, etc. By using any of these methods, the hacker gets control of the user activity which will lead to misuse of data, or stealth of users’ money or information. So, in order to overcome these problems and provide users with better security, we have proposed our multi step system, where the user will enter a simple text password, then draw a pattern on the image of his/her choice which was recorded while registration along with additional security features such as users email validation using OTP.

Design, computational studies, synthesis and biological evaluation of thiazole-based molecules as anticancer agents

BackgroundAbolition of cancer warrants effective treatment modalities directed towards specific pathways dysregulated in tumor proliferation and survival. The antiapoptotic Bcl-2 proteins are significantly altered in several tumor types which position them as striking targets for therapeutic intervention. Here we designed, computationally evaluated, synthesized, and biologically tested structurally optimized thiazole-based small molecules as anticancer agents. MethodsThe virtually designed 200 molecules were subjected to rigorous docking and in silico ADME-Toxicity studies. Out of this, 23 skeletally diverse thiazole-based molecules which passed pan assay interference compounds (PAINS) filter and were synthetically feasible were synthesized in 3 steps using cheap and readily available reagents. The molecules were in vitro evaluated against Bcl-2-Jurkat, A-431 cancerous cell lines and ARPE-19 cell lines. Molecular Dynamics (MD) simulation studies were performed to analyse conformational changes induced by ligand 32 in Bcl-2. Flow cytometry analysis of compound 32 treated Bcl-2 cells was done to check apoptosis. ResultsThe molecules exhibited appreciable interactions with Bcl-2 and were having acceptable drug like properties as tested in silico. The multi step synthesis yielded 23 skeletally diverse thiazole-based molecules in up to 80% yield. The molecules simultaneously inhibited Bcl-2 Jurkat cells in vitro without causing detectable toxicity to normal cells (ARPE-19 cells). Among them molecules 32, 50, 53, 57 and 59 showed considerable activities against Bcl-2 Jurkat and A-431cell lines at concentrations ranging from 32–46 μM and 34–52 μM, respectively. The standard doxorubicin exhibited IC50 in Bcl-2 Jurkat and A-431cell lines at 45.87 μM and 42.37 μM, respectively. The molecule 32, almost equipotent in both the cell lines was subjected to molecular dynamics (MD) simulation with Bcl-2 protein (4IEH). It was shown that 32 interacted with protein majorly via hydrophobic interactions and few H-bonding interactions. Fluorescence-activated cell sorting (FACS) analysis established that molecule is dragging cancerous cells towards apoptosis. Discussion and conclusionThe chemical intuition was checked by computation coupled with biological results confirmed that thiazole-based hits have the potential to be developed downstream into potent and safer leads against antiapoptotic Bcl-2 cells.

New heat treatment to improve the mechanical properties of low copper aluminum primary foundry alloy

The purpose of this work is to design a new heat treatment in order to improve the mechanical properties of primary 356 + 0.5 wt%Cu aluminum alloy. This heat treatment combines a multi step solution treatment with a quench and a multi step overaging treatment. It takes advantage of the evolution of the solubility limit of the matrix as a function of temperature in order to allow the appearance of successive precipitation sequences during excessive aging in several stages and leads to an increase in the volume fraction of precipitates.After T64 air quench, T6 air quench, T7 air quench and T7 water quench treatments and overaging 100 h at 150 °C, a secondary precipitation of Al2Cu particles is seen using conventional TEM, mostly after the T7 treatments. This secondary precipitation leads to an increase of the static mechanical properties. This dual-step overaging is then transposed to a dual-step aging T7 heat treatment, with aging 2h at 200 °C and 2h at 170 °C, and further compared to a classic T7 treatment with aging during 4h at 200 °C. Both heat treatments are also modeled using a KWN model. The model captures the secondary supersaturation of the proeutectic α-phase that leads to the secondary precipitation during the dual-step aging treatment. This translates to an increase of the mechanical properties by 6% and 3% for the yield strength and the ultimate tensile strength respectively. The elongation decreases by 33%.

Synthesis, Characterization and Thermal Analysis for New Amoxil Ligands

In the present study, new heterocyclic organic ligands were synthesized using amoxil drug as a starting material through multi steps. The ligands were prepared through condensation reaction to form thiazole and imidazole derivatives containing azo or anil groups in their structures via azotization reaction and imination reaction. The new ligands of amoxil have been characterized by means of spectral (IR and 1H NMR) and thermal analyses.

Robust Model Predictive Control for Uncertain Positive Time-delay Systems

This paper proposes the robust model predictive control of positive time-delay systems with interval and polytopic uncertainties, respectively. The model predictive control framework consists of linear constraint, linear performance index, linear Lyapunov function, linear programming algorithm, and cone invariant set. By virtue of matrix decomposition technique, robust model predictive controllers of interval and polytopic positive systems with multiple state delays are designed, respectively. A multi step control strategy is utilized and a cone invariant set is constructed. Linear programming is used for the corresponding MPC conditions. Finally, a numerical example is given to verify the effectiveness of the proposed design.

Nucleation and self-assembly dynamics of hierarchical YAlO3:Ce3+ architectures: Nano probe for in vitro dermatoglyphics and anti-mimetic applications

Highly efficient blue emitting YAlO3:Ce3+ (1–11 mol%) nanopowders have been fabricated via bio-surfactant Epigallocatechin Gallate assisted ultrasound irradiated sonochemical route. The nucleation and self-assembly dynamics of solids in solutions influences many straightforward normal processes, hence it plays a vital role in materials engineering applications. Nevertheless, the comprehensive nucleation and self-assembly mechanisms of hierarchical architectures still poorly acknowledged. In the present work, we have been exploring the nucleation and stepwise self-assembly dynamics of the YAlO3:Ce3+ (5 mol%) nanopowders into hierarchical architectures. We found that under ultrasound irradiation, nucleation in the solution forms via multi step process and self-assembly was stimulated by intermolecular forces between the nanopowders and external forces. The optimized YAlO3:Ce3+ (5 mol%) nanopowders used as a luminescent labeling agent for visualization of latent fingerprints on various porous and non-porous surfaces under ultraviolet 254 nm light. The obtained results exhibit well defined ridge details with high sensitivity, selectivity and low background hindrance which showed greater advantages as compared to the conventional powders. Extensive fingerprint details, namely the number and distribution of sweat pores in a ridge were clearly revealed. Further, demonstrated the viability of high-performance security labels using optimized sample for practical anti-mimetic applications. The present work, enabling understanding of ultrasound assisted nucleation and self-assembly of nanopowders which impart dermatoglyphics and anti- mimetic applications.

The influence of relative rolling reduction of sheet metal on the changes of deep drawing forces in multi drawing steps for cylindrical drawpiece without collar made from EN AW-1050A aluminium

The paper presents experimental results of investigations on deep drawing process of cylindrical drawpieces without collar in four drawing steps (single draw and three redraws). The research involved the use of EN AW-1050A aluminium blanks with diameter D = 66 mm. The material was prepared by rolling with different relative rolling reductions (z = 5%; 10%; 15% and 20%, respectively) at rolling mill DUO-100 and blanking process. In investigations of deep drawing, experimental force waveforms as the function of displacement for different relative rolling reductions of sheet metal made from aluminium were obtained.

In vitro bio-stability screening of novel implantable polyurethane elastomers

Abstract A series of novel biomedical TPCUs with different percentages of hard segment and a silicone component in the soft segment were synthesized in a multi-stage one-pot method. The kinetic profiles of the urethane formation in TPCU-based copolymer systems were monitored by rheological, in line FTIR spectroscopic (React IR) and real-time calorimetric (RC1) methods. This process-analytically monitored multi step synthesis was successfully used to optimize the production of medical-grade TPCU elastomers on preparative scale (in lots of several kg) with controlled molecular structure and mechanical properties. Various surface and bulk analytical methods as well as systematic studies of the mechanic response of the elastomer end-products towards compression and tensile loading were used to estimate the bio-stability of the prepared TPCUs in vitro after 3 months. The tests suggested that high bio-stability of all polyurethane formulations using accelerating in vitro test can be attributed to the synthetic design as well as to the specific techniques used for specimen preparation, namely: (i) the annealing for reducing residual polymer surface stress and preventing IES, (ii) stabilization of the morphology by long-time storage of the specimens after processing bevor being immersed in the test liquids, (iii) purification by extraction to remove the shot chain oligomers which are the most susceptible to degradation. All mechanical tests were performed on cylindrical and circular disc specimens for modelling the thickness of the meniscus implants under application-relevant stress conditions.

Direct addition of lithium and cobalt precursors to Ce0.8Gd0.2O1.95 electrolytes to improve microstructural and electrochemical properties in IT-SOFC at lower sintering temperature

To improve the microstructural and electrochemical properties of gadolinium-doped ceria (GDC) electrolytes, materials co-doped with 0.5–2 mol% of lithium and cobalt oxides were successfully prepared in a one-step sol gel combustion synthesis route. Vegard's slope theory was used to predict the dopant solubility and the sintering behaviour. The charge and size of the added dopant influence the atom flux near the grain boundary with a change in the lattice parameter. In fact, compared to traditional multi grinding steps, sol gel combustion facilitates molecular mixing of the precursors and substitution of the dopant cations into the fluorite structure, considerably reducing the sintering temperature. Adding precursors of lithium and cobalt, as dopant, increases the GDC densification and reduces its traditional sintering temperature down to 1000–1100 °C, with an improvement of electrochemical properties. Impedance analysis showed that the addition of 2 mol% of lithium or 0.5 mol% of cobalt enhances the conductivity with a consequent improvement of cell performances. High total conductivities of 1.26·10−1 S cm−1 and 8.72·10−2 S cm−1 at 800 °C were achieved after sintering at 1000 °C and 1100 °C for 2LiGDC and 0.5CoGDC, respectively.

A new modified definition of Caputo–Fabrizio fractional-order derivative and their applications to the Multi Step Homotopy Analysis Method (MHAM)

In this paper, we present a new definition of fractional-order derivative with a smooth kernel based on the Caputo–Fabrizio fractional-order operator which takes into account some problems related with the conventional Caputo–Fabrizio factional-order derivative definition. The Modified-Caputo–Fabrizio fractional-order derivative here introduced presents some advantages when some approximated analytical methods are applied to solve non-linear fractional differential equations. We consider two approximated analytical methods to find analytical solutions for this novel operator; the homotopy analysis method (HAM) and the multi step homotopy analysis method (MHAM). The results obtained suggest that the introduction of the Modified-Caputo–Fabrizio fractional-order derivative can be applied in the future to many different scenarios in fractional dynamics.

Recycling of Ni-Cd batteries by selective isolation and hydrothermal synthesis of porous NiO nanocuboid

Recycling batteries has become essential for improving sustainability, economy and environment. Batteries recycling and recovery processes are multi steps and require purified reagents which are often very toxic. Herein, we report a feasible approach to process scrap Ni-Cd batteries into highly porous NiO nanocuboids. Cathode of Ni-Cd battery contains approximately 42% elemental Ni along with several impurities such as Mg, Co, Cd and Na. In this work, by applying few-steps of selective isolation and hydrothermal treatment, the content of Ni could be raised up to 77% and purified in the form of NiO porous nanocuboids. Morphology, crystal structure, composition, and surface area measurements of NiO nanocuboids was studied by HR-TEM, FE-SEM, XRD, XPS and BET characterization techniques, respectively.

Method of Moments Estimators and Multi–step MLE for Poisson Processes

We introduce two types of estimators of the finite–dimensional parameters in the case of observations of inhomogeneous Poisson processes. These are the estimators of the method of moments and Multi–step MLE. It is shown that the estimators of the method of moments are consistent and asymptotically normal and the Multi–step MLE are consistent and asymptotically efficient. The construction of Multi–step MLE–process is done in two steps. First we construct a consistent estimator by the observations on some learning interval and then this estimator is used for construction of One–step and Two–step MLEs. The main advantage of the proposed approach is its computational simplicity.

Identification and quantitation of furan in irradiated fruit and vegetable juice

This paper describes the use of gas chromatography/mass spectroscopy (GC/MS) using static headspace sampling for the determination of furan in irradiated fruit and vegetable juice. The data presented demonstrate that furan is generated in juice as a result of treatment with ionizing radiation, but at low part-per-billion concentrations. The amount of furan increases with increasing dose in a non-linear second order relationship. Furthermore, it was found that furan interacts with the ionizing radiation in such a way that the amount of furan can be reduced in the absence of precursor compounds commonly found in juice products. Several possible precursors have been identified, including glucose, fructose, and ascorbic acid. We conclude that the formation of furan is complex and proceeds through a multi step process.

Effect of the Cooling Rate on the Graphite Nodule Count and Size Distribution in Nodular Cast Iron

The graphite nodule count, size distribution and homogenization of the nodules distribution are the factor which are of more significance for the properties of the material. By just increasing the inoculants or Mg will not help to get rid of problems like the un-even size distribution and or increasing the nodule count. The cooling conditions of the melt prior to solidification and during solidification can control these two parameters to a large extent. In this research, it is more emphasized on the nucleation sequence of MgO particles and on the cooling rates. The nucleation of MgO at different temperatures and at different cooling rates was found to have a great influence on the nodule size distribution and the homogenization of the microstructure. A mathematical model was derived to relate the Mg concentration in the liquid to the cooling rate, prior to solidification. The MgO particles count was calculated as a function of cooling rate. It was found that at higher cooling rates, MgO can be nucleated in multi steps during cooling process, which can increase the nodule count tremendously.