bluuebunny/crossref_metadata_2025 huggingface dataset:
Machine Learning, Ethics and Law
Authors: Miller Seumas
Published: May 2019

Recent revelations concerning data firm Cambridge Analytica’s illegitimate use of the data of millions of Facebook users highlights the ethical and, relatedly, legal issues arising from the use of machine learning techniques. Cambridge Analytica is, or was – the revelations brought about its demise - a firm that used machine learning processes to try to influence elections in the US and elsewhere by, for instance, targeting ‘vulnerable’ voters in marginal seats with political advertising. Of course, there is nothing new about political candidates and parties employing firms to engage in political advertising on their behalf, but if a data firm has access to the personal information of millions of voters, and is skilled in the use of machine learning techniques, then it can develop detailed, fine-grained voter profiles that enable political actors to reach a whole new level of manipulative influence over voters. My focus in this paper is not with the highly publicised ethical and legal issues arising from Cambridge Analytic’s activities but rather with some important ethical issues arising from the use of machine learning techniques that have not received the attention and analysis that they deserve. I focus on three areas in which machine learning techniques are used or, it is claimed, should be used, and which give rise to problems at the interface of law and ethics (or law and morality, I use the terms “ethics” and “morality” interchangeably). The three areas are profiling and predictive policing (Saunders et al. 2016), legal adjudication (Zeleznikow, 2017), and machines’ compliance with legally enshrined moral principles (Arkin 2010). I note that here, as elsewhere, new and emerging technologies are developing rapidly making it difficult to predict what might or might not be able to be achieved in the future. For this reason, I have adopted the conservative stance of restricting my ethical analysis to existing machine learning techniques and applications rather than those that are the object of speculation or even informed extrapolation (Mittelstadt et al. 2015). This has the consequence that what I might regard as a limitation of machine learning techniques, e.g. in respect of predicting novel outcomes or of accommodating moral principles, might be thought by others to be merely a limitation of currently available techniques. After all, has not the history of AI recently shown the naysayers to have been proved wrong? Certainly, AI has seen some impressive results, including the construction of computers that can defeat human experts in complex games, such as chess and Go (Silver et al. 2017), and others that can do a better job than human medical experts at identifying the malignancy of moles and the like (Esteva et al. 2017). However, since by definition future machine learning techniques and applications are not yet with us the general claim that current limitations will be overcome cannot at this time be confirmed or disconfirmed on the basis of empirical evidence.
Preface to Research on Applied Ethics (Cybersecurity)
Authors: Warren Matthew , Burmeister Oliver
Published: May 2019

This is the second special section on applied ethics for AJIS. As was the case for the first special section on ethics, of the various submissions, only three have been accepted for publication. This is not an indication that little work is being done in relation to cybersecurity ethics, but rather a reflection of the difficulty of getting published in a high quality journal. A great deal of research is being done in the area of ethics as regards cybersecurity, particularly in Europe as a result of the recent toughening of its privacy legislation and the implications that has for all manner of ethics and technology, from blockchain, to wearable robots and through to cybersecurity. An overview of those three articles follows, after which the guest editor backgrounds are described.
Near field analysis and field transformation applied to a parabolic profile at 5GHz
Authors: Peña-Ruiz S. , Sosa-Pedroza J. , Martinez-Zuñiga F. , Rodríguez-Sánchez A. , Garduño-Nolasco E. , Enciso-Aguilar And M.
Published: May 2019

We proposed a method of analysis and field transformation is applied to a 1.5 m diameter parabolic reflector at a frequency of 5 GHz, an antenna of these dimensions requires at least a 75 m region to obtain its radiation pattern, and this represents a problem, here arises the necessity to make field transformations like the one presented in this work. Near field is modeled by means of Finite Difference Time Domain Method (FDTD) and current distribution is obtained using the discrete Pocklington equation. Radiation pattern is calculated applying the array factor for parabolic profiles. Results are compared with those obtained by CST Microwave Studio with a very good agreement.
Design and implementation of a low-cost portable Raman spectrometer
Authors: Chiwo F. S. , Gonzalez And F.J.
Published: May 2019

Non-invasive medical diagnosis has become popular due to the possibility of detecting illnesses in vivo and in real time this technique, often referred to as "optical biopsy", comprises several optical techniques such as thermography, diffuse reflectance spectroscopy, optical coherence tomography and Raman spectroscopy among others. Particularly Raman spectroscopy is an optical technique based on the inelastic scattering of light that can detect disease markers, this technique has been successfully used to detect several types of diseases, however the high price of a Raman spectrometer makes it difficult for the medical community to adopt its use as a common diagnostic procedure. In this work a Raman spectroscopy system was designed and fabricated from low-cost readily available components. The system was characterized and the Raman spectra obtained was compared to commercial systems. Results show that it is possible to fabricate a custom Raman system with the desired optical configuration for non-invasive optical diagnosis at low costs and portable size.
CONJUGACIÓN PRÁCTICA PARA LA EVALUACIÓN FORMATIVA DEL APRENDIZAJE
Authors: Solano-García Cecilia G. , Argota-Pérez George , Chauca-de-Quispe Carmen L. , Pari- Olarte Josefa B. , Aliaga-Guillen Eusebio
Published: May 2019

La búsqueda de estrategias para el aprendizaje representa un desafío en el nivel educativo. El propósito del estudio fue la conjugación práctica para la evaluación formativa del aprendizaje en docentes universitarios. A partir de, la implementación del programa de posgrado referido al diplomado internacional ¨creatividad científica e innovación tecnológica¨ que se desarrolló en la Universidad Nacional ¨San Luis Gonzaga¨ de Ica, Perú se estableció un esquema de aprendizaje sobre 6 indicadores: variable de selección, enfoque de la investigación, tipo de artículo científico orientado, reconocimiento cognoscitivo, estructura metodológica de interés y criterio de interpretación y aporte. Fueron seleccionados de forma probabilística aleatoria, 3 docentes y mediante la técnica cuantitativa por análisis de contenido se consideró el nivel sobre el aprendizaje. Se estableció un código de puntuación de 12 a 20 siendo reconocido solamente como nivel de excelencia el rango de 18 a 20 puntos. Al comparar los resultados entre los docentes, hubo diferencias estadísticamente significativas (p<0,05) donde un docente se ubicó en el nivel de excelencia al obtener 18 puntos. Se requirió, la replicación de los indicadores en otras modalidades de la enseñanza para evaluar su posible contribución a la formación del aprendizaje en docentes universitarios.
ARAÑAS (ARACHNIDA: ARANEAE) ASOCIADAS A FORMACIONES VEGETALES EN EL REFUGIO DE VIDA SILVESTRE PANTANOS DE VILLA, LIMA, PERÚ
Authors: Alarcon Geancarlo , Alvariño Lorena , Iannacone Jose Alberto
Published: May 2019

En los humedales, las arañas juegan un papel importante en el reciclaje de nutrientes, al ingerir otros artrópodos y formar parte de la dieta de otros organismos consumidores. Se evaluó la aracnofauna asociada a las formaciones vegetales en el Refugio de Vida Silvestre Pantanos de Villa, Lima, Perú utilizando pitfall traps. Se calculó la diversidad alfa y beta, y los especímenes colectados fueron adjudicados a gremios alimentarios. Se capturaron un total de 10 familias. El gramadal salado fue la formación vegetal que obtuvo mayor riqueza de arañas. El índice de Pielou (J’) alcanzó su valor más alto en el juncal (0,84 bits·ind-1) y la dominancia de Simpson (C) mostró su valor más alto en el gramadal dulce (0,55 bits·ind-1). El índice cualitativo de Jaccard presentó una similitud del 43%, y el índice cuantitativo de Morisita-Horn mostró una similaridad del 68% entre formaciones vegetales. Las familias Lycosidae (50,65%), Sicariidae (17,53%) y Araneidae(14,94%) fueron las tres familias más abundantes, constantes y presentaron una distribución amontonada. Con relación al gremio trófico cualitativamente dominante en orden decreciente al porcentaje de familias fue: Cazadores errantes(CAE) (50%) > Cazadores al acecho (CAA) (20%) = Tejedoras de telas tridimensionales (TTT) (20%) > Tejedoras de telas orbiculares (TTO) (10%); sin embargo, por el número de especímenes fue: CAE (79%) > TTO (15%) > CAA (4%)> TTT (2%). Según los índices no paramétricos (Chao 2 y Jack 1), la curva de acumulación de familias de arañas nos reveló que los métodos empleados registraron entre 85% a 97,16% de las familias presentes. Se analiza la posibilidad deluso de las arañas como indicadoras de calidad ambiental.
Reduction of Irritation Potential Caused by Anionic Surfactants in the Use of Various Forms of Collagen Derived from Marine Sources in Cosmetics for Children
Authors: Klimaszewska Emilia , Seweryn Artur , Ogorzałek Marta , Nizioł-Łukaszewska Zofia , Wasilewski Tomasz
Published: May 2019

Surfactants, which are the basic ingredients in washing cosmetics, can cause skin irritation. In the case of washing cosmetics intended for children, it is necessary to select the composition in such a way as to ensure maximum reduction or even elimination of the irritant effect of the final product. The paper attempts to improve the safety of bath cosmetics for children by introducing: collagen amino acids (150 Da), hydrolysed collagen (12000 Da) and soluble collagen (300 000 Da). Zein value, bovine albumin, and human keratinocyte cell line studies have shown a significant decrease in the irritant potential of the compositions following the introduction of the proposed additives, which is more pronounced with the increase in the molecular weight of marine collagen. An important part of this work is a mechanism proposed by the authors, according to which the addition of the proposed additives can increase safety of the application of cosmetics for children.
Synthesis and Properties of 9,10-Dihydroxystearic Acid Ethoxylate
Authors: Zhang Lu , Sun Yongqiang , Di Serio Martino , Zhou Jingjie , Ding Lirong , Zhang Yong , Liang Huibin , Wu Huaping , Sun Jinyuan
Published: May 2019

In this paper, oleic acid was used as raw material to synthesize 9,10-di-hydroxystearic acid (DHSA), which contains two hydroxyl groups and one carboxyl group. DHSA was reacted with ethylene oxide (EO) to obtain a new surfactant category that is characterized by the presence of 3 hydrophilic chains: 9,10-di-hydroxystearic acid ethoxylates (DHSAE-n, n = 10, 12, 15, 18, 20 EO). FT-IR and 1H NMR were used to characterize the molecular structure of DHSAE-n. The surface activity, adsorption and aggregation behavior in aqueous solution have been investigated by static surface tension, dynamic surface tension, contact angle and transmission electron microscopy (TEM). In addition, the application properties (wettability, emulsification, foamability and decontamination) of DHSAE-n have been systematically studied.
Cracking of Aluminum Alloy Aircraft Undercarriage Forgings
Authors: Edwards J.O. , Pollard W.A. , Sebisty J.J.
Published: May 2019

Two complete aircraft undercarriage-leg 2014 aluminum alloy forgings and a number of sectional ends that exhibited cracks during nondestructive testing were examined to determine the extent of damage and the type of cracking. Cracks were primarily confined to the diaphragm and adjoining wall between the steel sleeve and the steel diaphragm washer. Metallographic analysis and accelerated corrosion tests showed that the cracks had originated as stress-corrosion failures.
Engine Accessory Angle Drive Gear Failure
Authors: Lamb S.R. , Clark G.
Published: May 2019

The failure of an ATAR engine accessory angle drive gear assembly caused an engine flame-out in a Mirage III aircraft of the Royal Australian Air Force (RAAF) during a landing. Stripping of the engine revealed that the bevel gear locating splines (16 NCD 13) had failed. Visual and low-power microscope examination of the spline of the shaft showed evidence of fretting wear debris; similar wear was observed on the splines of the mating bevel gear. It was concluded that the splines had failed by severe fretting wear. Fretting damage was also observed on the shaft face adjacent to the splines and on the bevel gear abutment shoulder. Additional tests included a metrological inspection of the shaft, bevel gear and support ring; metallographic examination of a section from the shaft; chemical analysis of the shaft material (16 NCD 13); and hardness testing of a sample of the yoke material. The wear had been caused by incorrect machining of the shaft splines, which prevented the bevel gear nut from locating correctly against the gear.
Fatigue Fracture of a C130 Aircraft Main Landing Gear Wheel Flange
Authors: Panontin Tina L.
Published: May 2019

A piece of wheel flange separated from the main landing gear wheel of a C130 aircraft as it taxied on a runway. The wheel was a 2014-T61 aluminum alloy forging and had been in service nearly 20 years. Fractographic evidence indicated that the initial crack growth was caused by high-cycle fatigue. The crack grew to approximately 8 in. in length before final catastrophic fracture. Fatigue analyses accurately predicted the cyclic life demonstrated by the failed wheel since its last inspection, assuming an initial crack length of 13 to 25 mm (0.5 to 1.0 in.). It was recommended that the inspection interval be reduced to one-third of its original duration for the current level of inspection reliability, or that inspection procedures be improved in order that cracks substantially smaller than 13 mm (0.5 in.) can be reliably detected.
Hydrogen-Assisted Fracture of a 17-4PH Airplane Wing Component
Authors: Meyn Dale A.
Published: May 2019

Cracks were discovered in the cast 17-4 PH stainless steel outboard leading edge flap support of an aircraft wing during overhaul inspection. Failure analysis focused on an apparently intergranular area of fracture surface. It was determined that the original mode of crack growth was cleavage, probably caused by cast-in hydrogen. The intergranular appearance resulted from heat treatment of the already cracked part, which caused the formation of grain-boundary “growth figures” on the exposed crack surfaces. It was recommended that the castings be more closely inspected for defects before further processing and that foundry practices be reviewed to correct deficiencies leading to excessive hydrogen absorption during melting and casting.
Mode III Fatigue Crack Growth Following the Curvature of the Heat-Affected Zone of a Type 321 Stainless Steel Spot Weld
Authors: Neff Michael
Published: May 2019

Several AISI type 321 stainless steel welded oil tank assemblies used on helicopter engine systems began to leak in service. One failure, a fracture on the aft side of a spot weld, was submitted for analysis. SEM fractography examination revealed fatigue failure. The failure initiated at an overload fracture near the root of the weld and was followed by mode III fatigue crack propagation (tearing) around the periphery of the weld. The initial overload fracture was caused by a high external load, which produced a concentrated stress and fracture at the weld root. The subsequent fatigue fracture was caused by engine vibrations during operation of the aircraft. Fracture characteristics indicated that the fatigue would not have occurred if the initial damage had not taken place.
Stress-Corrosion Cracking of a High-Strength Steel Frame in a Fighter Aircraft
Authors: White Tommy N. , Kantimathi Sam
Published: May 2019

Cracks were discovered between interference-fit fasteners (MoS2-coated Ti-6Al-4V) that had been incorporated into a fighter aircraft primary structural frame (D6ac steel) to enhance structural fatigue life. Examination of sections cut from the cracked frame established that the cracks propagated by stress-corrosion cracking. The cause of cracking was twofold: use of interference-fit fasteners exposed to moisture intrusion from a marine environment and poor hole quality. Failure was intensified by dissimilar-metal contact in the presence of weak acidic electrolyte (dissociated MoS2). Control of machining parameters to prevent formation of brittle martensite, use of galvanically compatible fasteners, and use of an alternate lubricant were recommended.
Examination of Broken Lamp Filaments Following a Rear-End Vehicular Collision
Authors: Johnson Alan A. , Lattimer Chauncey A.
Published: May 2019

A 1984 Chevrolet Blazer was being pushed by three youths after it ran out of gas when it was hit from behind by a 1979 Mercury Cougar. One of the youths was crushed between the two vehicles and killed. Optical microscopy was used to examine the tungsten filaments from the headlamps of the Cougar and from the four signal/emergency/parking lights of the Blazer to determine whether the vehicles lights were in use at the time of the accident. Based on degree of distension and brittle fragmentation, it was determined that the low-beam headlights of the Cougar and the parking lights of the Blazer were on at the time of the collision.
Fatigue Failure of a Steering Spindle on a Tricycle Agricultural Field Chemical Applicator
Authors: Orr Dean E.
Published: May 2019

The 4140 steel steering spindle on a tricycle agricultural field chemical applicator failed, causing the loss of the front wheel and overturn of the vehicle. The spindle was a solid 120 mm (4.75 in.) diam forging. It had been machined to 115 mm (4.5 in.) in diameter to fit tightly inside a collar at one point and to 90 mm (3.5 in.) for attachment to the steering mechanism at another. Visual examination showed that the spindle fractured at the fillet welds that attached it to the collar. Macrofractography and metallography revealed that the failure initiated at the root of a weld that bridged a wide gap. The most probable cause of failure was improper preheat during welding.
Failure of Brass Heat Exchanger Tubes
Authors: Sebrão M.Z. , Serra E.T.
Published: May 2019

A failure analysis was conducted on brass alloy 270 heat exchanger tubes that were pulled from a unit used to cool oil for the speed regulators and thrust bearings of a hydroelectric power plant. The tubes began to leak after approximately 5.5 years of service. Macrophotography and scanning electron microscopy were used to examine samples from the tubes. An energy-dispersive electron microprobe analysis was carried out to evaluate the zinc distribution. Results showed that the failure was due to dezincification. Replacement of the tubes with new tubes fabricated from a dezincification-resistant alloy was recommended.
Hydrotest Failure of a Carbon Steel Pressure Vessel
Authors: Warke William R.
Published: May 2019

A carbon steel (ASTM A515 grade 70) pressure vessel failed by brittle fracture while being hydro tested in the fabricating shop. The fracture origin was a small crack at a welding arc strike associated with the toe of a nozzle weld. A fracture mechanics calculation indicated that this imperfection, although small, initiated fracture because of the local geometry and stress conditions and the low toughness of the steel. It was recommended that (1) the probability of flaws be reduced by welding over or grinding out arc strikes, (2) the local stresses be lowered by post weld stress relief and improved weld toe geometry, and (3) toughness be improved by specifying fine-grain steel and/ or by normalizing.
Catastrophic Failure of an 1830 mm (72 in.) Diam Spiral-Welded Water Line
Authors: Jones W.F.
Published: May 2019

The repeated failure of a welded ASTM A283 grade D pipe that was part of a 6 km (4 mi) line drawing and conducting river water to a water treatment plant was investigated. Failure analysis was conducted on sections of pipe from the third failure. Visual, macrofractographic, SEM fractographic, metallographic, chemical, and mechanical property (tension and impact toughness) analyses were conducted. On the basis of the tests and observations, it was concluded that the failure was the combined result of poor notch toughness (impact) properties of the steel, high stresses in the joint area, a possible stress raiser at the intersection of the spiral weld and girth weld, and sudden impact loading, probably due to water hammer. Use of a semi- or fully killed steel with a minimum Charpy V-notch impact value of 20 J (15 ft·lbf) at 0 deg C (32 deg F) was recommended for future water lines. Certified test results from the steel mill, procedure qualification tests of the welding, and design changes to reduce water hammer were also recommended.
Field Replication of Stress-Corrosion Cracking in a Type 316 Stainless Pressure Vessel
Authors: Aaker Gordon , Agosta Paul
Published: May 2019

Field metallography and replication were performed on a type 316 stainless steel column in diglycol amine vacuum service to determine the cause of visible OD pitting on the column in several areas above the insulation support rings. The examination revealed transgranular stress-corrosion cracking beneath the pitted areas on the OD. The likely cause of the cracking was chloride stress corrosion, with chlorides deriving from the marine atmosphere and concentrating under the insulation around the support rings. A complete insulation evaluation, including repair or replacement, was recommended to prevent chloride buildup. Painting of the steel surface with an epoxy-phenolic or epoxy-coal tar was also suggested.
Stress-Corrosion Cracking of a Teflon-Lined Steel Pipe in Sulfuric Acid Service
Authors: Colwell Richard L.
Published: May 2019

A flanged 100 mm (4 in.) diam low-carbon steel spool piece lined with Teflon was removed from a sulfuric acid denitrification system after cracks were observed in the painted coating. Visual and microstructural examination along with SEM fractography revealed scaled iron oxides on all opened crack surfaces. The surfaces had a faceted morphology, indicating intergranular fracture. Cracks originated at the interface between the tube and the Teflon liner Corrosion products were found caked into the intergranular region between the liner and the spool. The portion of the liner that had been exposed to the process stream was discolored. Failure of the spool was attributed to stress-corrosion cracking promoted by the presence of nitrates. Nitric acid contaminant in the sulfuric acid stream had diffused through the liner and accumulated in the annular space. Use of a liner that is more impermeable to the diffusion of ionic species was recommended.
Failure of a Yoke Body of Master Slave Manipulator Due to Casting Defect
Authors: Kasiviswanathan K.V. , Muralidharan N.G. , Raj Baldev
Published: May 2019

A cast housing, part of a multi-shaft yoking mechanism, failed during assembly and installation of the equipment in which it was to be used. The housing, or yoke body, was cast from AISI 420 grade ferritic stainless steel. Analysis revealed that the failure was caused by the presence of shrinkage cavities, which lowered the load-bearing capability. The failure occurred at the location where there was an abrupt change in the section thickness. A redesign to provide a smooth contour at the section junction was recommended along with optimization of casting parameters to avoid shrinkage cavities.
Gear Failure of a Pressurized Heavy-Water Reactor Refueling Machine
Authors: Lorio Antonio F. , Crespi Juan C.
Published: May 2019

A gear belonging to a pressurized heavy-water reactor refueling machine failed after 10 years in service. The material specified for the gear was a type C90700 bronze. Macroscopic examination focused on three gear teeth that had fractured completely at the roots, and fracture zones were examined using SEM microscopy. Failure of the gears was attributed to heavy wear resulting from misalignment. A lack of adequate lubrication was also noted. Periodic alignment adjustment and lubrication were recommended.
Corrosion Failure of Four Pump Impellers
Authors: Tanner G. Mark
Published: May 2019

Copper alloy (C83600) impellers from two different feed pumps that supplied water to a 2-year-old boiler failed repeatedly. Examination by various methods indicated that the failures were caused by sulfide attack that concentrated in shrinkage voids in the castings. Two alternatives to prevent future failures were recommended: changing the impeller composition to a cast stainless steel, or implementing stricter nondestructive evaluation requirements for copper alloy castings.
Hot Cracking of a Pump Impeller From a Nuclear Plant
Authors: Czajkowski Carl J.
Published: May 2019

Liquid penetrant inspection of an ASTM A296 grade CA-15 residual heat removal pump impeller from a nuclear plant revealed a crack like indication that approximated the outer contour of the wear ring. Examination of a section containing the crack and three sections from near the main crack indication revealed that the failure was caused by hot cracking related to original weld repairs performed on the impeller casting.
Intergranular Cracking and Failure of Stainless Steel Vanes from a Closed, Riveted Impeller
Authors: Ebert Harry E.
Published: May 2019

Two Z-shape impeller vanes failed. The vane material was 14-hard type 301 stainless steel. The vanes were of two-piece construction, with a longitudinal weld. Analyses indicated that the vanes had not been solution annealed after welding, leaving the heat-affected zone above the welds in a highly sensitized state. The sensitized material lost corrosion resistance, became embrittled along the grain boundaries, and finally failed by intergranular cracking. Use of type 410 martensitic stainless steel was recommended.
Failure Analysis of a Cast Steel Crosshead
Authors: Chaudhari Mohan D.
Published: May 2019

A failed crosshead of an industrial compressor was examined using optical and scanning electron microscope. The crosshead was an ASTM A148 grade 105-85 steel casting. On the basis of the observations reported and available background information, it was concluded that the failure began with the initiation of cracks at slag inclusions and sharp fillets in weld-repair areas in the casting. The weld-repair procedures were unsatisfactory. The cracks propagated in a fatigue mode. he casting quality was judged unacceptable because of the presence of excessive shrinkage porosity. It was recommended that crosshead castings be properly inspected before machining. Revision of foundry practice to reduce or eliminate porosity was also recommended.
Surface Damage on a Transfer Gear Shaft
Authors: D'Antonio Carmine
Published: May 2019

An AISI 4320 H transfer gear shaft that was part of a transmission sustained severe surface damage after 12 h of dynamometer testing at various gearing and torque loads. The damage was characterized by generalized wear and spalling. Examination of a cross section of the shaft that intersected undamaged, burnished, and surface-spalled zones revealed no anomalies in the chemistry, microstructure, or hardness that could have caused the damage. The physical evidence suggested that the operable mechanism was contact fatigue caused by misalignment of the shaft in the assembly.
Failure of a Stud From a Boiler Manhole
Authors: Wellington K.G.
Published: May 2019

A stud that was part of a man hole cover on an old steam boiler broke when it was dropped. The boiler was more than 100 years old, but still performed satisfactorily when fired up at regular intervals. Chemical analysis showed the steel to be a low-carbon EN2 type. Microstructural examination indicated brittle fracture caused by strain aging. Replacement of all studs on the man hole cover and examination of the boiler steel in other places were recommended.
Hydrogen Embrittlement Failure of Socket Head Cap Screws
Authors: Tanner G. Mark
Published: May 2019

Several cadmium-plated carbon steel socket head cap screws that were part of a slide valve assembly on a regenerator line in a petrochemical plant failed during initial loading. Metallographic and XDS chemical analysis in conjunction with SEM examination of one failed and one unfailed cap screw indicated that the screws had failed by hydrogen embrittlement. The plating process was the likely source of the hydrogen. It was recommended that the remainder of the cap screws from the same lot as the failed screws be baked at approximately 190 deg C (375 deg F) for 24 h.
Stress-Corrosion Cracking of a Ship Propeller Tap Bolt
Authors: Thomson R.
Published: May 2019

An aluminum bronze propeller tap bolt from a twin-screw vessel fractured just below the bolt head. Liquid penetrant testing revealed a large network of cracks that extended radially from sites in and just below the bolthead. Metallographic analysis indicated that the tap bolt failed by stress-corrosion cracking. It was surmised that seawater or some other corrosive substance was present in sufficient quantity to induce intergranular cracking at regions of high stress concentration. It was recommended that all tap bolts be replaced with new bolts made from an alloy with a higher copper content and at least the same yield strength. Steps to exclude seawater and any possible source of ammonia from the bolt shank were also suggested.
Failure of a Heat-Resistant Sinter Belt
Authors: Dunning Ronald Jeffrey
Published: May 2019

A Nicrofer 3718 sinter belt used in a sinter furnace operated at 965 deg C (1770 deg F) for the curing of nickel briquettes stretched and fractured after only 6 months in service. Macrofractographic, metallographic, and chemical analyses of several broken links of the woven belt and an unused section of new wire showed that the fracture resulted from sulfur attack and overheating during service. It was recommended that the sinter belt material be changed to Nicrofer 3220-H (alloy 800H).
High-Temperature Failure by Perforation of Incoloy 800H Pigtails in Reformer Furnaces
Authors: Monteiro Sergio N.
Published: May 2019

The curved parts of exit pigtails made of wrought Incoloy 800H tubing used in steam reforming furnaces failed by performance after a period of service shorter than that predicted by the designers. Examination of a set of tubes consisting of both curved (perforated) and straight parts revealed that the cracks initiated at the outer surface by a combined mechanism of creep and intergranular embrittlement. A smaller grain size resulting from cold bending fabrication procedures for the curved parts was responsible for accelerating the embrittlement. It was recommended that hot bending be used for fabrication of the curved parts. A change of alloy to a low-alloy chromium-molybdenum allay to protect against heat was also suggested.
Hot Corrosion of Stainless Steel Grate Bars in Taconite Indurators
Authors: Mohanty Bani P. , Shores David A.
Published: May 2019

Grate bars in the traveling grate indurators in several taconite processing units suffered excessive corrosion following a conversion from acid to fluxed pellet production procedures. The campaign life of the HH grade cast stainless steel bars was reduced from more than 7 years to approximately 9 months. Several corroded grate bars were examined metallographically and by electron microscopy to determine the causes of the accelerated corrosion. Chemical and X-ray diffraction analyses were also conducted, along with simulation tests to assess the role of alkali chlorides in the corrosion process. The basic cause of degradation was found to be hot corrosion caused by the deposition of alkali sulfates and chlorides. However this degradation may have been aggravated by thermal cycling and abrasion. The source of the salt was impurities in the flux. Two potential solutions were proposed: modification of the processing parameters to reduce the salt deposition and / or change of bar materials to a more resistant alloy.
Hydrogen Embrittlement of P-110 Couplings for Mating 180 mm (7 in.) Casing in Oilfield Production
Authors: Peterson Clifford W. , Day James
Published: May 2019

Several tin plated, low-alloy steel couplings designed to connect sections of 180 mm (7 in.) diam casing for application in a gas well fractured under normal operating conditions. The couplings were purchased to American Petroleum Institute (API) specifications for P-110 material. Chemical analysis and mechanical testing of the failed couplings showed that they had been manufactured to the API specification for Q-125, more stringent specification than P-110, and met all requirements of the application. Fractographic examination showed that the point of initiation was an embrittled region approximately 25 mm (1 in.) from the end of the coupling. The source of the embrittlement was determined to be hydrogen charging during tin plating. Changes in the plating process were recommended.
Failure of an ASTM A681-89 H13 Die Segment for Die Casting of Aluminum
Authors: Goodrich George , Divinsky Ilya
Published: May 2019

A segment from a premium-quality H13 tool steel die for die casting of aluminum failed after only 700 shots. The segment was subjected to visual, macroscopic, hardness, and metallographic testing. The investigation revealed that failure occurred as a result of fatigue at an electrical-discharge-machined surface where the resulting rehardened layer had not been removed. This rehardened layer had cracked, providing a source for fatigue initiation.
Intergranular Corrosion Failure in Zn-Al Alloy Solenoid Valve Seats
Authors: Jayakumar T. , Bhattacharya D.K. , Raj Baldev , Rodriguez P.
Published: May 2019

Extensive cracking was found in a batch of die-cast ZAMAK 3 solenoid valve seats during commissioning of the system in which they were installed. Scanning electron microscopic and chemical analyses conducted on one of the failed valve seats showed that the composition of the alloy was different from that specified. The presence of excess aluminum and lead impurities that had segregated to the grain boundaries, coupled with an inadequate amount of magnesium, resulted in intergranular corrosion and subsequent intergranular failure. Corrosion was accelerated by storage in a humid environment in a coastal area. It was recommended that proper chemical analysis of the zinc-aluminum alloy be carried out as a quality control procedure.
Failure of an Aluminum Connector in an Electrical Transmission Cable
Authors: Furtado H.C. , Mannheimer W.A.
Published: May 2019

An 1100 aluminum alloy connector of a high-tension aluminum conductor steel-reinforced (ACSR) transmission cable failed after more than 20 years in service, in a region of consider able industrial pollution. The steel core was spliced with a galvanized 1020 carbon steel sheath. Visual examination showed that the connector had undergone considerable plastic deformation and necking before fracture. The steel sheath was severely corroded, and the steel splice was pressed off-center in the axial direction inside the connector. Examination of the fracture surface and micro-structural analysis indicated that the failure was caused by mechanical overload, which occurred because of weakening of the steel support cable by corrosion inside the fitting. The corrosion was ascribed to defective assembly of the connector which allowed moisture penetration.
Failure of Hot-Rolled Steel Bars
Authors: Stone Alan
Published: May 2019

Two 25 x 40 mm (1 x 1.5 in.) AISI 4150 hot-rolled steel bars that cracked during heat treatment were examined to determine whether the heat treating procedure had contributed to the failure. Metallographic examination of a cross section taken through the fracture revealed an oxide coating on both sides of the fracture surface. The oxide was also found on the top and bottom sides of the sample. Sawcut sides of the bar did not exhibit the oxide layer The presence of the oxide in the fracture, combined with its absence on all exterior surfaces, indicated that the fracture occurred as a result of an oxide seam in the original material rather than from oxide from heat treating. Nondestructive testing prior to machining and heat treatment was recommended.
Failure of the Bond Between a Cobalt Alloy Prosthetic Casting and a Sintered Porous Coating
Authors: Lisin Mark , Peterson Robert R.
Published: May 2019

A femoral knee implant was returned to the casting vendor for analysis after exhibiting poor bond strength between the cast substrate and a sintered porous coating. Both the coating and the substrate were manufactured from a cobalt-chromium-molybdenum alloy. Metallographic analysis indicated that a decarburized layer existed on all surfaces of the casting, which prevented bonding during the sintering thermal cycle. Bead-to-bead bonding within the coating appeared sufficient, and no decarburized layer was present on the bead surfaces. It was concluded that the decarburization did not occur during the sintering thermal cycle. It was recommended that the prosthetic manufacturer investigate atmosphere controls for all thermal cycles prior to coating.
Tensile Failure of a Hoist Chain Link
Authors: Casler Arvid A.
Published: May 2019

An ASTM A391 steel chain link of an over head hoist failed catastrophically, causing damage to both property and personnel. Macrofractography identified the sequence of fractures within the chain link. The first fracture occurred at the welded joint, a second occurred opposite the weld. SEM fractography and metallography indicated that the link failed in a ductile manner because of tensile overload, which occurred when the hoist hook contacted the hoist's housing and prevented uptake of the chain. It was recommended that a load-sensing device be installed to prevent future occurrences and that a dye penetrant inspection be performed on the renwinder of the chain.
Chloride-Induced Stress-Corrosion Cracking of Cooling Tower Hanger Rods
Authors: Weiss Wendy L.
Published: May 2019

One-quarter inch diameter 304 stainless steel cooling tower hanger rods failed by chloride-induced stress-corrosion cracking (SCC). The rods were located in an area of the cooling tower where the air contains drop lets of water below the mist eliminators and above the flow of water The most extensive cracking was observed in the rod nuts and in the portions of the rod which were covered by the nuts. Cracking was transgranular with extensive branching, and some corrosion occurred along the crack paths. The clamping force from the nuts used on both sides of the supported member and residual stresses from thread rolling likely contributed to the stresses for the cracking mechanism, along with the stresses induced by the supported load. The external surfaces of the hanger rods were reportedly exposed to a chloride-containing atmosphere, likely due to the biocide. Type 304 stainless steel is not a suitable material for this application, and materials that resist SCC, such as Inconel, should be considered.
Failure of a Laminated-Paper Food Cooking Tray
Authors: Leeser David O.
Published: May 2019

A laminated-paper microwave food tray collapsed with hot food in it. Microscopic examination of the failed tray revealed no structural or material defects. Five additional trays of like construction were also tested to determine the conditions necessary to simulate the permanent deflection of the tray handles that had occurred in the failed tray. Full distortion of the handles was obtained experimentally only by dropping a full hot tray on its end onto the floor. The test results indicated that the tray had slipped from the hand of the user.
Hydrogen Damage of Waterwall Tubes
Authors: Hahn Sarah Jane , Wiser Jimmy D.
Published: May 2019

Waterwall tube failure samples removed from a coal- and oil-fired boiler in service for 12 years exhibited localized underdeposit corrosion and hydrogen damage. EDS and XRD revealed that bulk internal deposits collected from the tubes contained metallic copper which can accelerate corrosion through galvanic effects and can promote hydrogen damage. Ultrasonic testing was recommended to locate tubes with severe gouging and corrosion, which are suspect locations for hydrogen damage. The source of the copper should be identified and future chemical cleaning of the boiler should address its presence in the waterwall tubes.
Failure of a Steel Wire Rope From a Television Tower
Authors: D'Antonio Carmine
Published: May 2019

A 6 x 19 fiber core steel wire rope failed as it was being used to lower a steel television tower. Fracture of the rope occurred at a point under one of two clips used to fashion a spliced loop that was directly connected to the top of the tower. Microscopic examination of the fracture surfaces and the condition of the individual wires revealed that 59% of the wires failed by shear, 39% failed in tension, and 2% had been cut. In addition, 87% of the wires showed some degree of crushing damage, ranging from mild to severe. The failure was attributed to improper installation of the clips.
Failure of a Transmission Brake Disc
Authors: Lochanski Edward C.
Published: May 2019

Failure of AISI 1015 steel brake discs used in power transmissions in emergency winches was investigated using various testing methods. The failed discs were stampings that had replaced cast discs. Residual stresses in the fillets of new cast and new stamped brake discs were measured by x-ray diffraction. The results indicated that the stamped brake discs had failed by fatigue caused by a tensile residual stress pattern in the fillet. The residual stress pattern was attributed to the change in manufacturing process from casting to stamping. Use of a manufacturing process that yields a compressive residual stress in the fillet, appropriate heat treatment of stamped discs, or redesign of the disc and/or transmission assembly was recommended.
Hydrogen Embrittlement Cracking in a Batch of Steel Forgings
Authors: Das A.K.
Published: May 2019

The repeated occurrence of random cracks in the fillet radius portion of low-alloy steel (38KhA) end frame forgings following heat treatment was investigated. Microstructural analyses were carried out on both the failed part and disks of the rolled bar from which the part was made. Subsurface cracks were found to be zigzag and discontinuous as well as intergranular in nature. A mixed mode of fracture involving ductile and brittle flat facets was observed. Micropores and rod-shaped manganese sulfide inclusions were also noted. The material had a hydrogen content of 22 ppm, and cracking was attributed to hydrogen embrittlement. Measurement of hydrogen content in the raw material prior to fabrication was recommended. Careful control of acid pickling procedures for descaling of the hot-rolled bars was also deemed necessary.
Mechanical Failure of a Repair Welded Ferritic Malleable Cast Iron Spring Hanger
Authors: Johnson Alan A. , von Fraunhofer Joseph A.
Published: May 2019

The right front spring hanger on a dual rear axle of the tractor of a tractor-trailer combination failed, causing the vehicle to roll-over. The hanger was made from malleable cast iron that had been heat treated to produce a decarburized surface layer and a pearlitic transition layer. It had been repair welded after breaking into two pieces longitudinally in a prior incident, using cast iron as weld metal. The repair weld bead on both surfaces missed the fracture over 15 to 20% of their lengths. The incomplete repair weld and brittleness of the weld metal and heat-affected zones led to the failure.
Dealloying in Aluminum Bronze Components
Authors: Czajkowski Carl J.
Published: May 2019

Various aluminum bronze valves and fittings on the essential cooling water system at a nuclear plant were found to be leaking. The leakage was limited to small-bore socket-welded components. Four specimens were examined: three castings (an ASME SB-148 CA 952 elbow from a small-bore fitting and two ASME SB-148 CA 954 valve bodies) and an entire valve assembly. The leaks were found to be in the socket-weld crevice area and had resulted from dealloying. It was recommended that the weld joint geometry be modified.
Thermal Fatigue Failure of Alloy UNS NO8800 Steam Superheating Tubes
Authors: Islam Moavinul
Published: May 2019

Alloy UNS N08800 (Alloy 800) tubes of the steam superheating coils of two hydrocracker charge heaters in a refinery failed prematurely in service. Failure analysis of the tubes indicated that the failures could be attributed to thermal fatigue as a result of temperature fluctuations as well as restriction to movement. Fatigue cracks initiated intergranularly from both the flue gas and steam sides. Enhanced general and grain boundary oxidation coupled with age hardening of the alloy led to the formation of incipient intergranular cracks that acted as sites for the initiation of the fatigue cracks.
Failure of a Stainless Steel Tank Used for Storage of Heavy Water/Helium
Authors: Dayal R.K. , Chandrasekharan N.
Published: May 2019

The dished ends of a heavy water/helium storage tank manufactured from 8 mm (0.3 in.) thick type 304 stainless plate leaked during hydrotesting. Repeated attempts at repair welding did not alleviate the problem. Examination of samples from one dished end revealed that the cracking was confined to the heat affected zone (HAZ) surrounding circumferential welds and, to a lesser extent, radial welds that were part of the original construction. Most of the cracks initiated and propagated from the inside surface of the dished ends. Microstructures of the base metal, HAZ, and weld metal indicated severe sensitization in the HAZ due to high heat input during welding. An intergranular corrosion test confirmed the observations. The severe sensitization was coupled with residual stresses and exposure of the assembly to a coastal atmosphere during storage prior to installation. This combination of factors resulted in failure by stress-corrosion cracking. Implementation of a new repair procedure was recommended. Repairs were successfully made using the new procedure, and all cracks in the weld repair zones were eliminated.
Failure of AISI Type 347 Stainless Steel Bellows
Authors: Muralidharan N.G. , Kaul Rakesh , Kasiviswanathan K.V. , Raj Baldev
Published: May 2019

A number of AISI 347 stainless steel bellows intended for use in the control rod drive mechanism of a fast breeder reactor were found to be leaking before being placed in service. The bellows, which had been in storage for one year in a seacoast environment, exhibited a leak rate on the order of 1 x 10−7 cu cm/s (6 x 10−8 cu in./s). Optical metallography revealed numerous pits and cracks on the surfaces of the bellow convolutes, which had been welded to one another using an autogenous gas tungsten arc welding process. Microhardness measurements indicated that the bellows had not been adequately stress relieved. It was recommended that a complete stress-relieving treatment be applied to the formed bellows. Improvement of storage conditions to avoid direct and prolonged contact of the bellows with the humid, chloride-containing environment was also recommended.
Failure Analysis of Turbine Blades
Authors: Iorio Antonio F. , Crespi Juan C.
Published: May 2019

Two 20 MW turbines suffered damage to second-stage blades prematurely. The alloy was determined to be a precipitation-hardening nickel-base superalloy comparable to Udimet 500, Udimet 710, or Rene 77. Typical protective coatings were not found. Test results further showed that the fuel used was not adequate to guarantee the operating life of the blades due to excess sulfur trioxide, carbon, and sodium in the combustion gases, which caused pitting. A molten salt environmental cracking mechanism was also a factor and was enhanced by the working stresses and by the presence of silicon, vanadium, lead, and zinc. A change of fuel was recommended.