Alumina Effect on the Phase Transformation of 3Y-TZP Ceramics

The isothermal tetragonal-to-monoclinic phase transformation of 3 mol fraction Y2O3-ZrO2 ceramics contain- ing different amounts of Al2O3 during ageing in water at 130℃ for periods of time up to 40 h was investigated to explore the effect of Al2O3 addition on this transformation. The propagation of the transformation into the specimen interiors was suppressed by the addition of Al2O3. The transformation kinetics showed a nucleation and growth mechanism on the specimen surface to be dominant in the low temperature ageing in water environment.     

Dipper Throated Algorithm for Feature Selection and Classification in Electrocardiogram

Arrhythmia has been classified using a variety of methods. Because of the dynamic nature of electrocardiogram (ECG) data, traditional handcrafted approaches are difficult to execute, making the machine learning (ML) solutions more appealing. Patients with cardiac arrhythmias can benefit from competent monitoring to save their lives. Cardiac arrhythmia classification and prediction have greatly improved in recent years. Arrhythmias are a category of conditions in which the heart's electrical activity is abnormally rapid or sluggish. Every year, it is one of the main reasons of mortality for both men and women, worldwide. For the classification of arrhythmias, this work proposes a novel technique based on optimized feature selection and optimized K-nearest neighbors (KNN) classifier. The proposed method makes advantage of the UCI repository, which has a 279-attribute high-dimensional cardiac arrhythmia dataset. The proposed approach is based on dividing cardiac arrhythmia patients into 16 groups based on the electrocardiography dataset’s features. The purpose is to design an efficient intelligent system employing the dipper throated optimization method to categorize cardiac arrhythmia patients. This method of comprehensive arrhythmia classification outperforms earlier methods presented in the literature. The achieved classification accuracy using the proposed approach is 99.8%.     

Effect of manganese substitution on the magnetic properties of nickel-zinc ferrite

The effect of manganese (Mn)-ion substitution on the structural, magnetic, and electrical properties of nickel-zinc (Ni-Zn) ferrite of chemical formula Ni_0.6−t Mn _t Zn_0.4Fe₂O₄ (t=0.0, 0.1, 0.2, 0.3, 0.4, 0.45, 0.5, 0.55, 0.6) has been studied. It was found that Mn ion substitution increases the average grain diameter and improves the magnetization as well as the initial permeability. At the same time, the direct current (dc) resistivity at room temperature was found to increase with Mn ion substitution. The increase of both magnetization and dc resistivity due to the Mn substitution in a Ni-Zn ferrite is a promising result for applications in high-frequency fields.     

Optimization of Electrocardiogram Classification Using Dipper Throated Algorithm and Differential Evolution

Electrocardiogram (ECG) signal is a measure of the heart’s electrical activity. Recently, ECG detection and classification have benefited from the use of computer-aided systems by cardiologists. The goal of this paper is to improve the accuracy of ECG classification by combining the Dipper Throated Optimization (DTO) and Differential Evolution Algorithm (DEA) into a unified algorithm to optimize the hyperparameters of neural network (NN) for boosting the ECG classification accuracy. In addition, we proposed a new feature selection method for selecting the significant feature that can improve the overall performance. To prove the superiority of the proposed approach, several experiments were conducted to compare the results achieved by the proposed approach and other competing approaches. Moreover, statistical analysis is performed to study the significance and stability of the proposed approach using Wilcoxon and ANOVA tests. Experimental results confirmed the superiority and effectiveness of the proposed approach. The classification accuracy achieved by the proposed approach is (99.98%).     

Localized Corrosion Behavior of 6% Mo Super Austenitic & 316L Stainless Steels in Low pH 3% NaCl Solution

Electrochemical techniques were applied to study the crevice corrosion resistance of two types of stainless steel alloys namely, conventional 316L and 6% Mo super austenitic in acidified 3% NaCI solution at room temperature. Potentiodynamic results showed that 6% Mo alloy possessed a remarkable resistance to crevice corrosion compared with 316L alloy when they are tested in the same solution. The breakdown potential at which passivity broke down for 316L alloy was 0.00 mV (SCE). The corresponding value for 6% Mo alloy could not reach up to the potential value of 700 mV (SCE). 316L alloy suffered extremely from crevice corrosion at room temperature (about 25℃), which indicates that the critical crevice corrosion temperature, below which crevice corrosion does not occur, was lower than the test temperature. For 6% Mo alloy, the critical crevice corrosion temperature was higher than the testing temperature. Electrochemical parameters indicated that 6% Mo alloy exhibited higher crevice corrosion resistance than 316L alloy.     

Wheat Starch Modification Through Biotechnology

Natural mutations that affect the amylose/amylopectin ratio in starch are unlikely to develop naturally in wheat due to its allohexaploid genome (2n=6x; AABBDD). One of the strategies to modify wheat starch structure involves identification of germplasms with null alleles for starch biosynthetic genes, followed by exchange of functional alleles with the identified null alleles through classical plant breeding. This technique has successfully been used to combine the three null alleles for granule-bound starch synthase I (GBSSI) to develop a wheat line that produces amylopectin-rich (>95%) starch (waxy starch). Another strategy to alter expression levels of starch biosynthetic genes employs recent advances in molecular biology and genetic engineering of wheat. For this approach, various monocot vectors have been developed that drive expression of wheat starch branching enzyme I (SBEI) cDNA sequences in the anti-sense orientation. Several of the wheat cell lines transformed with the anti-sense vectors express branching enzyme (BE) activity at a significantly lower level than non-transformed cells. One transgenic wheat plant expressing the anti-sense SBEI RNA produces a ten-fold lower level of BE activity in kernels than wild-type wheat. Analysis of starch produced from the transgenic plant shows that starch structure and properties have been altered.     

A study on Claisen Condensation with Diethyl Anilinodiacetate

Sodium hydride prompted reactions of diethyl anilinodiacetate 1 with acetophenone, p-nitroacetophenone, p-fluoroacetophenone and acetylthiophene result in the formation of tetraketones 3a–d . Evidence is presented to support the formation of 3a–d , via a sequence of reactions involving condensation with hydrazine, their acetyl derivatives, and cyclization with polyphosphoric acid. The structures of the hitherto unknown ring systems have been confirmed by i.r., p.m.r. and mass spectral data.     

EMF measurements on gadolinia doped ceria

An experimental set up was built to measure the EMF, which is generated out of the oxygen partial pressure gradient, across the faces of solid electrolyte samples. The results obtained from this work show that ceria-gadolinia mixed oxide, of composition Ce_0·825Gd_0·175O_1·913, behaves in a manner quite satisfactory for use as an oxygen ion conducting material in fuel cells. This is especially true at relatively low temperatures (as low as 600°C) and with oxygen partial pressure down to 10⁻⁵ atm. The oxygen mean ionic transport number was shown to be almost unity at the above mentioned temperature and oxygen partial pressure.     

Evaluation of Shear Design Equations of Concrete Beams with FRP Reinforcement

Several codes and design guidelines addressing fiber-reinforced polymer (FRP) bars as primary reinforcement for structural concrete have been recently published worldwide. This reflects the great progress in FRP research area that has been conducted by the research community over the past two decades. Most of these design provisions follow the traditional approach of Vc+Vs for shear design. Nevertheless, both equations of concrete contribution Vc and FRP stirrup contribution Vs to shear strength in these guidelines are different in the manner that they are calculated. In this paper, five methods for FRP shear design, currently used in design practice, were reviewed. These methods include the American Concrete Institute design guide, ACI 440.1R-06; the Canadian Standards Association, CAN/CSA-S806-02; the ISIS Canada design manual, ISIS-M03-07; the British Institution of Structural Engineers guidelines; and the design recommendations of the Japan Society of Civil Engineers. The five methods for shear design prescribed in these guidelines were compared with experimental database obtained from the literature. In addition, the modified compression field theory approach was reviewed and compared with the experimental database.     

Yttria Tetragonal Zirconia Biomaterials:Kinetic Investigation

The low temperature aging behavior of polycrystalline tetragonal zirconia was investigated to explore the effects on phase transformation occurring during the process.XRD analysis was conducted for the phase identification and the tetragonal to monoclinic phase transformation was determined.The aging of tetragonal zirconia polycrystals doped with 3 mol% Y2O3 triggers tetragonal to monoclinic phase transformation on the surface of the specimen only,while the penetration inside the bulk of the specimen is very limited.A slight decrease in the mechanical properties was also observed after aging for 40 h.The transformation kinetics show a nucleation and growth mechanism on the specimen surface to be dominant in the low temperature aging in water environment.