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

IMMERSION ULTRASONIC INSPECTION SYSTEM FOR SMALL SCALED COMPOSITE SPECIMEN

ABSTRACT Ultrasonic testing is a common Non-Destructive Test (NDT) technique used especially in flaw detection for various material such as metal, plastic and composite. However, detecting flaw on a composite material is likely more difficult because of its non-homogenous characteristics. An ultrasonic scanning unit is developed in previous research focusing at the inspection on a composite material. In this paper, the improvement and modification to the system is revised and discussed in term of system configuration, specification, controls and also inspection results. The major improvement is made on the heart of the machine as the scanning mechanism is changed from using an air-coupled transducer to an immersion transducer. Current immersion transducer used is 2.25MHz which is highly recommended for a composite material. A combination of Arduino board and a self-developed graphical user interface (GUI) are used in order to control the position of the transducer and to run the inspection process. The data is acquired from pulse receiver to the computer for further data processing and interpretation. The machine is tested with fibre glass composite laminates (FGCL) sample with holes as artificial defect

Effects of high power electronics converters on PLC signals

The harmonics are generated by the switching operation of large power converters, such as Static Compensator (STATCOM), Static Reactive Power Controller (SVC) and UPFC. These harmonics may cover a wide range of frequencies and it can cause problems of interference with communication systems. Power Line Carrier (PLC) system is one of the systems used in transmission of signals for Tele-potations, Tele-tripping, Tele-control and speech communications. The Signal to Noise Ratio (SNR) of the PLC is based on the noise level at the input of the carrier receiver. These effects of harmonics result in overheating, extra losses in electric machines and capacitors; and over voltage due to excited resonance in the power system. The main source of disturbances resulting from harmonics has been proved to be from a high power converter. This problem becomes more complicated when harmonics are originating in many single source. These harmonics can be propagated throughout the entire interconnected power network. The interference due to large power converter will be superimposed on the background noise at lower levels causing it to reduce the SNR to an unacceptable value. This study deals with the analysis of the waveform of the converters and the methods used to reduce the noise imposed on PLC communication signal. © 2006 Asian Network for Scientific Information

Myocardial energy depletion and dynamic systolic dysfunction in hypertrophic cardiomyopathy

Evidence indicates that anatomical and physiological phenotypes of hypertrophic cardiomyopathy (HCM) stem from genetically mediated, inefficient cardiomyocyte energy utilization, and subsequent cellular energy depletion. However, HCM often presents clinically with normal left ventricular (LV) systolic function or hyperkinesia. If energy inefficiency is a feature of HCM, why is it not manifest as resting LV systolic dysfunction? In this Perspectives article, we focus on an idiosyncratic form of reversible systolic dysfunction provoked by LV obstruction that we have previously termed the 'lobster claw abnormality' — a mid-systolic drop in LV Doppler ejection velocities. In obstructive HCM, this drop explains the mid-systolic closure of the aortic valve, the bifid aortic pressure trace, and why patients cannot increase stroke volume with exercise. This phenomenon is characteristic of a broader phenomenon in HCM that we have termed dynamic systolic dysfunction. It underlies the development of apical aneurysms, and rare occurrence of cardiogenic shock after obstruction. We posit that dynamic systolic dysfunction is a manifestation of inefficient cardiomyocyte energy utilization. Systolic dysfunction is clinically inapparent at rest; however, it becomes overt through the mechanism of afterload mismatch when LV outflow obstruction is imposed. Energetic insufficiency is also present in nonobstructive HCM. This paradigm might suggest novel therapies. Other pathways that might be central to HCM, such as myofilament Ca2+ hypersensitivity, and enhanced late Na+ current, are discussed

New broad-spectrum resistance to septoria tritici blotch derived from synthetic hexaploid wheat

Septoria tritici blotch (STB), caused by the ascomycete Mycosphaerella graminicola, is one of the most devastating foliar diseases of wheat. We screened five synthetic hexaploid wheats (SHs), 13 wheat varieties that represent the differential set of cultivars and two susceptible checks with a global set of 20 isolates and discovered exceptionally broad STB resistance in SHs. Subsequent development and analyses of recombinant inbred lines (RILs) from a cross between the SH M3 and the highly susceptible bread wheat cv. Kulm revealed two novel resistance loci on chromosomes 3D and 5A. The 3D resistance was expressed in the seedling and adult plant stages, and it controlled necrosis (N) and pycnidia (P) development as well as the latency periods of these parameters. This locus, which is closely linked to the microsatellite marker Xgwm494, was tentatively designated Stb16q and explained from 41 to 71% of the phenotypic variation at seedling stage and 28–31% in mature plants. The resistance locus on chromosome 5A was specifically expressed in the adult plant stage, associated with SSR marker Xhbg247, explained 12–32% of the variation in disease, was designated Stb17, and is the first unambiguously identified and named QTL for adult plant resistance to M. graminicola. Our results confirm that common wheat progenitors might be a rich source of new Stb resistance genes/QTLs that can be deployed in commercial breeding programs

Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV

Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe