Corrosion of a chrome-moly pipe transporting sulfuric acid in a demineralization section: a failure analysis

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Andres Marquez ◽  
Chris Maharaj
Keyword(s):  
Sulfuric Acid ◽  
Material Selection ◽  
Real Life ◽  
Main Idea ◽  
Petrochemical Plant ◽  
Material Loss ◽  
Corrosion Failure ◽  
Content Type ◽  
Characterization Methods ◽  
X Ray

Purpose The purpose of this study was to carry out an analysis of the corrosion failure on a chrome-moly pipeline transporting highly concentrated sulfuric acid in a demineralization section at a petrochemical plant, along with the feasibility of using inhibitors to minimize the corrosive effects of sulfuric acid. Design/methodology/approach X-ray fluorescence spectroscopy, high-resolution optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and accelerated corrosion experiments (ACE) were performed. Findings Erosion-corrosion failure was confirmed by the significant reduction in thickness of the internal surface of the material exposed to sulfuric acid, as well as the formation of an oxide scale/layer. ACE accurately predicted high material loss from exposure to sulfuric acid. Moreover, adding ascorbic acid as a corrosion inhibitor (even at low concentrations) was found to reduce the oxidation by more than 50% in the presence of sulfuric acid. Originality/value The main idea/purpose of this work relies on the analysis of recurrent real-life corrosion-attributed failures that are common in industry but are not properly addressed for a variety of reasons, poor management and lack of corrosion preventive strategies being the main ones. This study once again highlights readily available solutions/implementations that are capable of not only addressing technically the issue investigated but also, and as important, economically. By using microscopic imaging, reliable well-tested and widely used characterization methods, all combined with basic experiments and tests, the nature of the repetitive failure investigated was clearly demonstrated as well as readily available alternatives to minimize it in the short term. Nevertheless, implementing material selection techniques appropriately as effective corrosion prevention/control and cost-saving strategies must be enforced in any process.

Investigation into rotary mode ultrasonic drilling of bioceramic: an experimental study with PSO-TLBO based evolutionary optimization

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ravi Pratap Singh ◽  
Narendra Kumar ◽  
Ashutosh Kumar Gupta ◽  
Madhusudan Painuly
Keyword(s):  
Mathematical Model ◽  
Feed Rate ◽  
Fitness Function ◽  
Real Life ◽  
Spindle Speed ◽  
Ultrasonic Power ◽  
Material Loss ◽  
Additional Advantage ◽  
Content Type ◽  
Ultrasonic Drilling

Purpose The purpose of this paper is to investigate experimentally the effect of several input process factors, namely, feed rate, spindle speed, ultrasonic power and coolant pressure, on hole quality measures (penetration rate [PR] and chipping diameter [CD]) in rotary mode ultrasonic drilling of macor bioceramic material. Design/methodology/approach The main experiments were planned using the response surface methodology (RSM). Scanning electron microscopy was also used to examine and study the microstructure of machined samples. This study revealed the existence of dominant brittle fracture and little plastic flow that resulted in a material loss from the base work surface. Experiment findings have shown the dependability and adequacy of the proposed mathematical model. Findings The percentage of brittle mode deformation rises as the penetration depth of abrasives increases (at increasing levels of feed rate). This was due to the fact that at greater depths of indentation, material loss begins in the form of bigger chunks and develops inter-granular fractures. These stated causes have provided an additional advantage to increasing the CD over the machined rod of bioceramic. The desirability method was also used to optimize multi-response measured responses (PR and CD). The mathematical model created using the RSM method will be very useful in industrial revelation. Furthermore, the investigated answers’ particle swarm optimization (PSO) and teacher-learner-based optimization (TLBO) make the parametric analysis more relevant and productive for real-life industrial practices. Originality/value Macor bioceramic has been widely recognized as one of the most highly demanded innovative dental ceramics, receiving expanded industry approval because of its outstanding and superior characteristics. However, effective and efficient processing remains a problem. Among the available contemporary machining methods introduced for processing typical and advanced materials, rotary mode ultrasonic machining has been identified as one of the best suitable candidates for precise processing of macor bioceramics, as this process produces thermal damage-free profiles, as well as high accuracy and an increased material removal rate. The optimized combined setting obtained using PSO is feed rate = 0.16 mm/s, spindle speed = 4,500 rpm, ultrasonic power = 60% and coolant pressure = 280 kPa with the value of fitness function is 0.0508. The optimized combined setting obtained using TLBO is feed rate = 0.06 mm/s, spindle speed = 2,500 rpm, ultrasonic power = 60% and coolant pressure = 280 kPa with the value of fitness function is 0.1703.

Corrosion of copper exposed to Zhanjiang and Zhuhai atmospheric environments

2017 ◽  
Vol 64 (3) ◽  
pp. 286-292 ◽  
Author(s):  
Wei Su ◽  
Wangyan Lv ◽  
Zhengchun Liu ◽  
Zengguang Zhang
Keyword(s):  
Corrosion Behavior ◽  
Material Selection ◽  
Southern China ◽  
Coastal Region ◽  
Exposure Period ◽  
X Ray Diffraction ◽  
Content Type ◽  
X Ray ◽  
Exposure Site ◽  
One Year

Purpose The aim of this paper was to study the initial corrosion behavior of copper in the substations of Zhanjiang and Zhuhai. Design/methodology/approach The copper exposed at the substation of Guangdong coastal region in southern China for up to 12 months. The rust layer formed on the copper has been examined by scanning electron microscopy, X-ray energy spectrum, X-ray diffraction and electrochemical polarization techniques. Findings The corrosion weight loss of copper at Zhanjiang exposure site is a little more serious than that at Zhuhai exposure site in every exposure period. The corrosion products of copper have different changes in color and composition at the two exposure sites. The tensile strength of copper has a slight decrease after one-year exposure. Originality/value The atmospheric exposure experiments of copper in the substations of Zhanjiang and Zhuhai have been adopted for the first time. The corrosion behavior of copper was investigated, and it can provide reference for material selection of the substation.

Low-cycle fatigue behavior and corrosion mechanism of pre-corroded 2A70-T6 aluminum alloy

2020 ◽  
Vol 67 (2) ◽  
pp. 228-239
Author(s):  
Hui Li ◽  
Lei Fu ◽  
Li Lin ◽  
Yu Chen ◽  
YunRong Luo ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Atmospheric Corrosion ◽  
Fatigue Behavior ◽  
Fatigue Performance ◽  
Corrosion Mechanism ◽  
Accelerated Corrosion ◽  
Corrosion Failure ◽  
Content Type ◽  
X Ray

Purpose In summary, it can be found that the current research on the simulation of natural atmospheric dry–wet alternating accelerated corrosion mainly focused on the study of electrochemical corrosion process and the study of corrosion rate; the micro-pre-corrosion mechanism of materials in this environment, especially for materials. The specific effects of fatigue and fracture performance still lack detailed research. Accordingly, this study aims to more realistically simulate the effect of natural atmospheric corrosion environment on the corrosion resistance and fatigue performance of aircraft skin. Design/methodology/approach In this study, the uniaxial strain control method was used to test the fatigue performance of pre-corrosion samples under simulated natural atmospheric corrosion using MTS809 tensile-torque composite fatigue machine. Scanning electron microscopy, X-ray energy spectrum analysis, atomic force microscopy and X-ray diffraction analysis were used. Fatigue fracture, corrosion morphology and corrosion products were analyzed. Findings The results show that the deep corrosion pit caused by pre-corrosion environment leads to multi-source initiation of crack; the fatigue life of pre-corroded sample decreases by about one-half, chloride ion invades the material and promotes intergranular corrosion; life prediction results show that the natural atmospheric corrosive environment mainly affects the plastic term in the Manson–Coffin formula resulting in a decrease in fatigue life. Originality/value Innovative experimental schemes and materials are used and the test temperature and relative humidity are strictly controlled. The corrosion failure mechanism of 2A70-T6 aluminum alloy under alternating wet and dry accelerated corrosion environment and its influence on fatigue behavior were obtained.

scholarly journals Spectral Tomography for 3D Element Detection and Mineral Analysis

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 598
Author(s):  
Jose R. A. Godinho ◽  
Gabriel Westaway-Heaven ◽  
Marijn A. Boone ◽  
Axel D. Renno
Keyword(s):  
Energy Spectrum ◽  
3D Imaging ◽  
X Rays ◽  
3D Images ◽  
Characterization Methods ◽  
X Ray ◽  
Additional Information ◽  
Mineral Phases ◽  
Spectral Computed Tomography

This paper demonstrates the potential of a new 3D imaging technique, Spectral Computed Tomography (sp-CT), to identify heavy elements inside materials, which can be used to classify mineral phases. The method combines the total X-ray transmission measured by a normal polychromatic X-ray detector, and the transmitted X-ray energy spectrum measured by a detector that discriminates between X-rays with energies of about 1.1 keV resolution. An analysis of the energy spectrum allows to identify sudden changes of transmission at K-edge energies that are specific of each element. The additional information about the elements in a phase improves the classification of mineral phases from grey-scale 3D images that would be otherwise difficult due to artefacts or the lack of contrast between phases. The ability to identify the elements inside the minerals that compose ore particles and rocks is crucial to broaden the application of 3D imaging in Earth sciences research and mineral process engineering, which will represent an important complement to traditional 2D imaging mineral characterization methods. In this paper, the first applications of sp-CT to classify mineral phases are showcased and the limitations and further developments are discussed.

Characteristic properties of AlTiN and TiN coated HSS materials

2015 ◽  
Vol 67 (2) ◽  
pp. 172-180 ◽  
Author(s):  
Mumin Sahin ◽  
Cenk Misirli ◽  
Dervis Özkan
Keyword(s):  
Surface Roughness ◽  
Tensile Strength ◽  
High Speed ◽  
Cutting Tools ◽  
High Speed Steel ◽  
Wear Properties ◽  
Content Type ◽  
X Ray ◽  
Number Of Cycles ◽  
Future Work

Purpose – The purpose of this paper is to examine mechanical and metallurgical properties of AlTiN- and TiN-coates high-speed steel (HSS) materials in detail. Design/methodology/approach – In this study, HSS steel parts have been processed through machining and have been coated with AlTiN and TiN on physical vapour deposition workbench at approximately 6,500°C for 4 hours. Tensile strength, fatigue strength, hardness tests for AlTiN- and TiN-coated HSS samples have been performed; moreover, energy dispersive X-ray spectroscopy and X-ray diffraction analysis and microstructure analysis have been made by scanning electron microscopy. The obtained results have been compared with uncoated HSS components. Findings – It was found that tensile strength of TiAlN- and TiN-coated HSS parts is higher than that of uncoated HSS parts. Highest tensile strength has been obtained from TiN-coated HSS parts. Number of cycles for failure of TiAlN- and TiN-coated HSS parts is higher than that for HSS parts. Particularly TiN-coated HSS parts have the most valuable fatigue results. However, surface roughness of fatigue samples may cause notch effect. For this reason, surface roughness of coated HSS parts is compared with that of uncoated ones. While the average surface roughness (Ra) of the uncoated samples was in the range of 0.40 μm, that of the AlTiN- and TiN-coated samples was in the range of 0.60 and 0.80 μm, respectively. Research limitations/implications – It would be interesting to search different coatings for cutting tools. It could be the good idea for future work to concentrate on wear properties of tool materials. Practical implications – The detailed mechanical and metallurgical results can be used to assess the AlTiN and TiN coating applications in HSS materials. Originality/value – This paper provides information on mechanical and metallurgical behaviour of AlTiN- and TiN-coated HSS materials and offers practical help for researchers and scientists working in the coating area.

scholarly journals Characterization of Airborne Bacteria at an Underground Subway Station

2012 ◽  
Vol 78 (6) ◽  
pp. 1917-1929 ◽  
Author(s):  
Marius Dybwad ◽  
Per Einar Granum ◽  
Per Bruheim ◽  
Janet Martha Blatny
Keyword(s):  
Real Life ◽  
Performance Criteria ◽  
Anthropogenic Sources ◽  
Subway Station ◽  
Airborne Bacteria ◽  
Surveillance Systems ◽  
Operational Environment ◽  
Biological Detection ◽  
Content Type ◽  
Subway Stations

ABSTRACTThe reliable detection of airborne biological threat agents depends on several factors, including the performance criteria of the detector and its operational environment. One step in improving the detector's performance is to increase our knowledge of the biological aerosol background in potential operational environments. Subway stations are enclosed public environments, which may be regarded as potential targets for incidents involving biological threat agents. In this study, the airborne bacterial community at a subway station in Norway was characterized (concentration level, diversity, and virulence- and survival-associated properties). In addition, a SASS 3100 high-volume air sampler and a matrix-assisted laser desorption ionization–time of flight mass spectrometry-based isolate screening procedure was used for these studies. The daytime level of airborne bacteria at the station was higher than the nighttime and outdoor levels, and the relative bacterial spore number was higher in outdoor air than at the station. The bacterial content, particle concentration, and size distribution were stable within each environment throughout the study (May to September 2010). The majority of the airborne bacteria belonged to the generaBacillus,Micrococcus, andStaphylococcus, but a total of 37 different genera were identified in the air. These results suggest that anthropogenic sources are major contributors to airborne bacteria at subway stations and that such airborne communities could harbor virulence- and survival-associated properties of potential relevance for biological detection and surveillance, as well as for public health. Our findings also contribute to the development of realistic testing and evaluation schemes for biological detection/surveillance systems by providing information that can be used to mimic real-life operational airborne environments in controlled aerosol test chambers.

Relational governance in outsourcing partnerships

2016 ◽  
Vol 26 (4) ◽  
pp. 435-452 ◽  
Author(s):  
Anuradha Mathrani ◽  
Sanjay Mathrani
Keyword(s):  
Real Life ◽  
Service Level ◽  
Positive Influence ◽  
Control Measures ◽  
Offshore Outsourcing ◽  
Relational Exchange ◽  
Relational Governance ◽  
Content Type ◽  
Governance Practices ◽  
Narrative Storylines

Purpose The paper aims to capture the nuances of two client–supplier relationships to offer new insights on the influences of transactional, knowledge and social elements in outsourcing partnerships. Design/methodology/approach The study has used descriptive case studies with narrative storylines. Interviews were conducted with three relationship managers (boundary gatekeepers) to understand preferred governance practices between clients and suppliers in diverse economic markets. Findings Experiences of three real-life cases engaged in offshore outsourcing have helped to identify the market, operational knowledge and social influences in a relational exchange. Findings reveal that offshore partnerships are first constituted with service-level agreements, which set control measures and layout business expectations from both partners. Boundary gatekeepers bring further accountability across firms by designing social networks for capturing and sharing of knowledge, thereby reducing each partner’s perception of risk. As firms evaluate transactional, knowledge and social elements for building a futuristic relational exchange, more disaggregated and dispersed enterprises evolve as new opportunities are explored in foreign markets. Research limitations/implications The retrospective nature of the client–supplier partnership is a limitation in this research study. However, retrospection adds to experience, and to practice perspectives made in hindsight, and therefore has a positive influence in this study. Originality/value This paper shares real-world experiences that can be used by scholars and practitioners to better understand how relational governance practices operate in a global socio-economic setting.

Study in performance and morphology of polyamide 12 produced by selective laser sintering technology

2018 ◽  
Vol 24 (5) ◽  
pp. 813-820 ◽  
Author(s):  
Junjie Wu ◽  
Xiang Xu ◽  
Zhihao Zhao ◽  
Minjie Wang ◽  
Jie Zhang
Keyword(s):  
Selective Laser Sintering ◽  
Polarized Light ◽  
Chain Scission ◽  
High Energy ◽  
Laser Sintering ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Content Type ◽  
X Ray ◽  
Polyamide 12

Purpose The purpose of this paper is to investigate the effect of selective laser sintering (SLS) method on morphology and performance of polyamide 12. Design/methodology/approach Crystallization behavior is critical to the properties of semi-crystalline polymers. The crystallization condition of SLS process is much different from others. The morphology of polyamide 12 produced by SLS technology was investigated using scanning electron microscopy, polarized light microscopy, differential scanning calorimetry, X-ray diffraction and wide-angle X-ray diffraction. Findings Too low fill laser power brought about bad fusion of powders, while too high energy input resulted in bad performance due to chain scission of macromolecules. There were three types of crystal in the raw powder material, denoted as overgrowth crystal, ring-banded spherulite and normal spherulite. Originality/value In this work, SLS samples with different sintering parameters, as well as compression molding sample for the purpose of comparison, were made to study the morphology and crystal structure of sintered PA12 in detail.

Kenneth Fisher’s heuristics

2016 ◽  
Vol 8 (2) ◽  
pp. 130-148
Author(s):  
Carlo Massironi ◽  
Giusy Chesini
Keyword(s):  
Decision Making ◽  
Conceptual Analysis ◽  
Investment Decision ◽  
Real Life ◽  
Human Action ◽  
Theory Of Knowledge ◽  
Constructivist Theory ◽  
Individual Investors ◽  
Content Type ◽  
Radical Constructivist

Purpose The authors are interested in building descriptive – real life – models of successful investors’ investment reasoning and decision-making. Models designed to be useful for trying to replicate and evolve their reasoning and decision-making. The purpose of this paper, a case study, is to take the substantial material – on innovating the investing tools – published in four books (2006/2012, 2010, 2011, 2015) by a US stock investor named Kenneth Fisher (CEO of Fisher Investments, Woodside, California) and sketch Fisher’s investment innovating reasoning model. Design/methodology/approach To sketch Fisher’s investment innovating reasoning model, the authors used the Radical constructivist theory of knowledge, a framework for analyzing human action and reasoning called Symbolic interactionism and a qualitative analytic technique called Conceptual analysis. The authors have done qualitative research applied to the study of investment decision-making of a single professional investor. Findings In the paper, the authors analyzed and described the heuristics used by Fisher to build subsequent generations of investing tools (called by Fisher “Capital Markets Technology”) to try to make better forecasts to beat the stock market. The authors were interested in studying the evolutive dimensions of the tools to make forecasts of a successful investor: the “how to build it” and “how to evolve it” dimension. Originality/value The paper offers an account of Kenneth Fisher’s framework to reason the innovation of investing tools. The authors believe that this paper could be of interest to professional money managers and to all those who are involved in the study and development of the tools of investing. This work is also an example of the use of the Radical constructivist theory of knowledge, the Symbolic interactionist framework and the Conceptual analysis to build descriptive models of investment reasoning of individual investors, models designed to enable the reproduction/approximation of the conceptual operations of the investor.

Anterior sacral meningocele contiguous with a pelvic hamartoma

1984 ◽  
Vol 61 (1) ◽  
pp. 188-190 ◽  
Author(s):  
Eugene Leibowitz ◽  
William Barton ◽  
Parvis Sadighi ◽  
Jeffrey S. Ross
Keyword(s):  
Computerized Tomography ◽  
Content Type ◽  
Transabdominal Approach ◽  
X Ray ◽  
Anterior Sacral Meningocele ◽  
Fine Print

✓ A patient with an anterior sacral meningocele combined with a hamartoma was diagnosed with x-ray films, myelography, and computerized tomography. She was successfully operated on by a transabdominal approach.

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