Fatigue performance of thermal spray coatings on carbon steel: a review

This paper contributes to a review of the research of the fatigue behaviour of thermal spray coatings on carbon steel. Previous studies provide the experimental characterization of the fatigue resistance of coated carbon steel. Different coating powders were deposited to a different type of carbon steels. Also, S-N curves were drawn from axial- and rotating bending fatigue test to determine the fatigue strength or fatigue limit of the samples. Thermal spray coatings showed great improvement to the work hardening effect but worsen the fatigue life due to the inclusion of oxide and pores, the presence of stress concentrators, and high microcrack density. Moreover, the effects of the surrounding environment have also resulted in pros and cons towards the fatigue strength. An improvement, however, can be done with the shot peening treatment, which significantly increases the compressive residual stress at interfaces of coating/substrate. The high compressive residual stress could delay the crack nucleation, thus increasing the fatigue life of the coated part

Simulation analysis of ultrasonic testing in steel-based butt weld joint

Within this study, a simulation analysis based on Ultrasonic Testing (UT) is made using Comsol Multiphysics. Comsol Multiphysics is a software that can simplify many aspects of building UT method and also can be used to obtain a fast understanding of the results of altering the fundamental parameters. The software program has useful features which can help in technique development especially for UT inspectors in Non- destructive Testing (NDT) field. The focus of this study is to conduct a simulation analysis of internal weld defects by developing the model of defects in a weld structure sample configured using the software. The model is developed based on actual parameters and characterization of weld structure sample and internal weld defects. The results of analysis show that each type of defects which are incomplete penetration, slag inclusion and lack of fusion have different signal pattern and signal amplitude which are depended on the characterizations of those defects themselves

An Intelligent Advisor for City Traffic Policies

Nowadays, city streets are populated not only by private vehicles but also by public transport, fleets of workers, and deliveries. Since each vehicle class has a maximum cargo capacity, we study in this article how authorities could improve the road traffic by endorsing long term policies to change the different vehicle proportions: sedans, minivans, full size vans, trucks, and motorbikes, without losing the ability of moving cargo throughout the city. We have performed our study in a realistic scenario (map, road traffic characteristics, and number of vehicles) of the city of Malaga and captured the many details into the SUMO microsimulator. After analyzing the relationship between travel times, emissions, and fuel consumption, we have defined a multiobjective optimization problem to be solved, so as to minimize these city metrics. Our results provide a scientific evidence that we can improve the delivery of goods in the city by reducing the number of heavy duty vehicles and fostering the use of vans instead.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This research has been partially funded by the Spanish MINECO and FEDER projects TIN2014-57341-R, TIN2016-81766-REDT, and TIN2017-88213-R. University of Malaga, Andalucia TECH. Daniel H. Stolfi is supported by a FPU grant (FPU13/00954) from the Spanish MECD. Christian Cintrano is supported by a FPI grant (BES-2015-074805) from Spanish MINECO

High watermarking capacity based on spatial domain technique

Watermarking capacity refers to the amount of information we are able to insert into the image. Low signal to noise ratio is a phenomenon of watermarking channels, which severely limits the capacity. The aim of this study is to develop a digital watermarking model, which can find out the possibility to embed maximum amount of data in an image without degrading the quality of watermarked image. In this approach, the host image will be partitioned into non-overlapping blocks and passing an imaginary plane in the three critical pixels. The characteristics of this plan should not be changed after embedding message; then the same characteristics will be used to evaluate the embedded capacity in the extracting module

Full factorial design analysis approach for preparation of poly(HEMA-co-EGDMA-co- VBC) microsphere particles

The application of a more reliable full factorial experiment has not been well-explored in studies of crosslinked polymer synthesis. In this paper, statistically full factorial design experimental was explored in the study of poly(HEMA-co-EGDMA-co-VBC) synthesis via suspension polymerization. Three independent factors, i.e. monomer concentration (HEMA), amount of crosslinker (EGDMA) and amount of co-monomer (VBC) were investigated to study the effect and interaction factors on morphology and yield of terpolymer particles in 23 factorial design of experiments. The percentage of EGDMA was found to be the most significant factor affecting the morphology of particle, with good quality particles obtained when the percentage of EGDMA increasing. Meanwhile, the factorial analysis suggests that all of the factors show a significant effect on particles yield, with more than 80% yield obtained when all factors was increased

Assessment the Effect of Some Reagents on the Planktonic Cells and Biofilms of Red Complex Periodontal Pathogens

The current study aimed to investigate the effectiveness of four regents; two naturals, olibanum and alum, and two standards, ciprofloxacin (CIP) and chlorhexidine (CHX) to affect the growth and biofilm of three types of periodontal pathogens, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia, "the red complex group". Clinical isolates of the red complex pathogens were isolated from chronic periodontitis. They were identified by phenotypic properties and molecular method. The inhibitory activity of the four reagents was tested by microdilution method. Minimal inhibitory concentration (MIC) on the bacterial plankton and minimal biofilm inhibitory concentration (MBIC) on biofilm of the four reagents in a single and combinational use was determined on mono- and polymicrobial populations. Simple linear regression modeling was used to explore the effect of each reagent and determine MICs and MBICs. All reagents showed inhibition activity against the growth of mono- and polymicrobial planktonic population. MIC values on polymicrobial growth were higher than on monomicrobial growth and MBICs were much higher. All reagents had antibacterial activity on a monomicrobial biofilm with greater significant effect on T. denticola then T. forsythia and P. gingivalis. On polymicrobial biofilm, just olibanum continued showing its effect whilst CHX was less effect and both alum and CIP had no effect. Combinational use with Olibanum encouraged the effect of other regents on polymicrobial biofilm. This combination is a promising medicated preparation to combat the subgingival plaque of red complex pathogens

Assessing Malaysian crowdsourcing platforms using web of system performance (WOSP) model

Crowdsourcing allows organizations and individuals to tap into a large pool of people to accomplish tasks. Recent growth in crowdsourcing has triggered Malaysia to venture into crowdsourcing initiatives. This study intends to assess the performance of crowdsourcing platforms in Malaysia using the Web of System Performance (WOSP) model.The results give insights on the current state of crowdsourcing platforms in Malaysia and highlight the gaps that exist in these platforms. This eventually help to enhance the design of current platforms and promote higher uptake of crowdsourcing among Malaysians

Velocity profile measurement of solid particles using LED as a light source

Optical sensors have been widely available and used in medical applications and industries for decades. Its design comes in a wide range of varieties where each are tailored based on its type, use, size, nature of investigated materials etc. In this work, we focus on the development and investigation of an optical sensing module, which uses Light Emitting Diode (LED) as the light source and LED photosensor as detector. This sensor is to measure the velocity of a solid particle in a gas flow inside a closed pipe. Various factors such as power dissipation, wavelength of the light source, switching time and cost are considered in the design process of this sensor. The cross correlation technique is used to determine the flow rate where small particles were introduced in a natural gas flow and they went through two distanced sets of sensor module. The LED beam source in the first set of sensor will be scattered when the particle crosses it then the corresponding photodetector will collect the light signal received and generates a pulse signal. The second pulse signal is generated when the particle crosses the second set of sensor after an interval of time. The time interval measured is used to calculate the velocity of the flow. An analysis of the received pulse signals is made to determine the best configurations of the sensors. At the end of this study, we were able to develop a simple, working, and cost effective sensing module

Effect of selective heart rate slowing in heart failure with preserved ejection fraction

Background Heart failure with preserved ejection fraction (HFpEF) is associated with significant morbidity and mortality but is currently refractory to therapy. Despite limited evidence, heart rate reduction has been advocated, on the basis of physiological considerations, as a therapeutic strategy in HFpEF. We tested the hypothesis that heart rate reduction improves exercise capacity in HFpEF. Methods and Results We conducted a randomized, crossover study comparing selective heart rate reduction with the If blocker ivabradine at 7.5 mg twice daily versus placebo for 2 weeks each in 22 symptomatic patients with HFpEF who had objective evidence of exercise limitation (peak oxygen consumption at maximal exercise [GraphicO2 peak] <80% predicted for age and sex). The result was compared with 22 similarly treated matched asymptomatic hypertensive volunteers. The primary end point was the change in GraphicO2 peak. Secondary outcomes included tissue Doppler–derived E/e′ at echocardiography, plasma brain natriuretic peptide, and quality-of-life scores. Ivabradine significantly reduced peak heart rate compared with placebo in the HFpEF (107 versus 129 bpm; P<0.0001) and hypertensive (127 versus 145 bpm; P=0.003) cohorts. Ivabradine compared with placebo significantly worsened the change in GraphicO2 peak in the HFpEF cohort (-2.1 versus 0.9 mL·kg−1·min−1; P=0.003) and significantly reduced submaximal exercise capacity, as determined by the oxygen uptake efficiency slope. No significant effects on the secondary end points were discernable. Conclusion Our observations bring into question the value of heart rate reduction with ivabradine for improving symptoms in a HFpEF population characterized by exercise limitation

The impact of adding fetal MRI to sonographically diagnosed intrauterine ventriculomegaly: a prospective cohort study

Objective: Intrauterine fetal ventriculomegaly (IVM) is one of the most commonly detected fetal anomalies. Prenatal diagnosis in IVM is considered a challenge with a significant impact on management. The current study aims to evaluate the added value of performing fetal MRI to sonographically diagnosed IVM. Methods: A prospective cohort study was conducted at a tertiary University Hospital in the period between January 2017 and March 2019. We included pregnant women with a single fetus sonographically diagnosed IVM (symmetrical or asymmetrical). First, a basic obstetric sonographic examination was done, followed by a detailed (2D/3D) fetal CNS anomaly scan for the detection of other associated anomalies. A fetal MRI brain scan was performed for all cases. Results: Sixty women were included in the study. Of the 60 fetuses with IVM, additional findings were seen on MRI in 14 cases (23%), and most of these findings were identified in fetuses with severe IVM (about 50%). No additional abnormalities were identified in fetuses of less than 24 weeks gestation. Callosal and septum pellucidum lesions (29%), along with posterior fossa abnormalities (28%) and cortical malformations (21%) accounted for the most common additional significant fetal MRI findings. Fetal MRI sensitivity, specificity, and positive and negative predictive values in correlation with those of prenatal ultrasound turned out to be notably higher, approaching nearly 100 %. Conclusions: Fetal MRI for sonographically diagnosed moderate or severe IVM is recommended to guide clinical management