bluuebunny/crossref_metadata_2025_split huggingface dataset:
Free-Form Processing of Near-Net Shapes Using Directed Light Fabrication
Authors: Thoma D.J. , Lewis G.K. , Milewski J.O. , Nemec R.B. 
Published: May 2021

Abstract
Directed light fabrication (DLF) is a rapid fabrication process that fuses gas delivered metal powders within a focal zone of a laser beam to produce fully dense, near-net shape, 3D metal components from a computer generated solid model. Computer controls dictate the metal deposition pathways, and no preforms or molds are required to generate complex sample geometries with accurate and precise tolerances. The DLF technique offers unique advantages over conventional thermomechanical processes or thermal spray processes in that many labor and equipment intensive steps can be avoided to produce components with fully dense microstructures. Moreover, owing to the flexibility in power distributions of lasers, a variety of materials have been processed, ranging from aluminum alloys to tungsten, and including intermetallics such as M05Si3. Since DLF processing offers unique capabilities and advantages for the rapid fabrication of complex metal components, an examination of the microstructural development hhas been performed in order to define and optimize the processed materials. Solidification studies of DLF processing have demonstrated that a continuous liquid/solid interface is maintained while achieving high constant cooling rates that can be varied between 10 to 105 Ks-1 and solidification growth rates ranging up to 10-2 ms-1.
The Electric Arc Spray Manufacture of Rapid Production Tooling: A Case Study
Authors: Newbery A.P. , Grant P.S. , Jordan R.M. , Roche A.D. , Carr T.C. 
Published: May 2021

Abstract
The manufacture of tooling using the electric arc spray process to spray steel directly onto a master pattern offers substantial reductions in the lead times required to make complex tooling for polymer injection moulding and other applications. The process of spray forming is fast, efficient, and low cost, and has been shown to be dimensionally accurate with proper control over the residual stresses that develop during spraying. Poor dimensional control because of high internal stresses in thick arc sprayed steel coatings is well known, but these problems can be avoided by the use of correct spraying conditions. This paper describes the steps of the spray forming process used to make tooling for polymer injection moulding. The spray forming route competed directly with a traditional method for toolmaking and considerably reduced the lead time from order to completion. The tooling produced by spray forming has been operating commercially in production in the U.S. and has to date produced in the region of half a million parts without appreciable wear. The incorporation of contoured cooling channels during spraying has enabled plastic injection moulding cycle times to be decreased by 15%.
Impact Toughness of Thick Multilayer Thermal Spray Deposits
Authors: Verdy C. , Coddet C. , Martin J.B. , Garcia J.C. , Pellerin F. 
Published: May 2021

Abstract
The aim of this study was to investigate potential weight savings using multi-layer blade containment systems for turboengines. The association of an external ductile layer with an internal hard layer could provide a good ductility of the armor with the capability to withstand the perforation of high kinetic projectiles. Comparisons between several thick deposits obtained by the vacuum plasma spray process were performed using a Charpy impact testing machine. Mechanical and structural characterisations of these two-layer structures were performed and compared to the behavior of monolithic ones. Heat treatment effects were also considered.
VPS Deposition of Spherical Ti-Based Powders Produced by Plasma Atomization
Authors: Grenier S. , Brzezinski T. , Tsantrizos P. , Allaire F. 
Published: May 2021

Abstract
A new plasma atomization process was developed for the production of spherical metal powders. This process, unique in its ability to produce large quantities of fine powders (&lt; 75 µm), is especially interesting for value added products such as refractory or reactive metals/alloys powders. The excellent feeding characteristics of spherical powders make them ideal for applications such as injection molding and vacuum plasma spray (VPS) deposition. Powders are known to have a significant influence on the final characteristics of VPS deposited coatings. A variety of factors will control the coating quality, including: powder chemistry, morphology, microstructure, and feeding behaviour. This article includes a review of titanium coatings, and new results obtained using plasma atomized spherical powders.
Porosity Control of Thermally Sprayed Ceramic Deposits
Authors: Chraska P. , Brozek V. , Kolman B.J. , Ilavsky J. , Neufuss K. , Dubsky J. , Volenik K. 
Published: May 2021

Abstract
This paper examines ways to control the porosity of thermally sprayed deposits. All spraying was done with a water-stabilized plasma system using different combinations of alumina, zircon, Ni, and Al powders. Sandwiched structures with alternating ceramic and metal layers were sprayed as were thick deposits consisting of metal and ceramic mixtures. Porosity was characterized by methods such as gas permeability, water immersion, MIP, SEM, and SANS. In addition, several post-processing methods were tested to determine their effect on porosity volume. For example, removing metallic phases by leaching or by annealing at temperatures above the melting point was found to effectively increase porosity, while the use of sealing materials proved effective at reducing porosity. Another method tested was calcination, which resulted in an increase or decrease of porosity depending on the deposit's chemistry and annealing conditions.
Surface Preparation and Thermal Spray in a Single Step: The Protal Process
Authors: Coddet C. , Montavon G. , Marchione T. , Freneaux O. 
Published: May 2021

Abstract
Thermal spray techniques can fulfill numerous industrial applications. Coatings are hence applied to resist against wear, corrosion, or to modify the surface characteristics of the substrate (e.g., conductivity, etc.). However, many of these applications remain inhibited by some deposit characteristics, such as a limited coating adhesion or pores, or by industrial costs since several non-synchronized steps (i.e., degreasing, sand-blasting and spraying) are needed to manufacture a deposit. The Protal process was designed to reduce the aforementioned difficulties by implementing simultaneously a Q-switched laser and a thermal spray torch. The laser irradiation is aimed to eliminate the contamination films and oxide layers, to generate a surface state enhancing the deposit adhesion and to limit the contamination of the deposited layers by condensed vapors. From Protal arises the possibility to reduce, indeed suppress, the preliminary steps of degreasing and sand-blasting. In addition, in some cases, a significant increase in the deposit adhesion versus standard preparation, a decrease of the porosity level and the increase of the deposit cohesion represent important additional effects of the process.
Splat Formation – First Step of Multitechnique Deposition Plasma Spraying and Microwave Plasma Enhanced CVD
Authors: Denoirjean A. , Grimaud A. , Fauchais P. , Tristant P. , Tixier C. , Desmaison J. 
Published: May 2021

Abstract
This paper presents the results of a study of the morphology of alumina splats deposited on stainless steel and alumina substrates. The substrates were either plasma sprayed or coated via plasma enhanced CVD. Substrates that were plasma sprayed were annealed if necessary to get specific phase structures, then polished to around 0.4 μm (Ra). CVD-coated substrates with an Ra ~6 nm and a columnar amorphous structure were sprayed as deposited. Splat studies show that the crystal structure of alumina substrates and the release of entrapped gas have a major influence on splat formation. For plasma sprayed coatings, disk-shaped splats with excellent adhesion properties were obtained on hot γ alumina, while on α alumina, splat shape and morphology were irregular and adhesion very poor. The effect of entrapped gas, on the other hand, can be seen in the splats that formed on the CVD-coated substrates. These splats were very porous and, in many, most of alumina flowed out to rim. As the paper explains, this is the result of gas release upon impact of molten particles, which reduces wettability and thermal contact between the splat and substrate.
Thermal Spraying on Graphite
Authors: Mesrati N. , Ajhrourh H. , Du N. , Treheux D. 
Published: May 2021

Abstract
In order to expand the fields of application and to improve the performance of graphite (Cg), it is necessary to reduce its permeability towards of oxygen and to limit its reactivity and especially its oxidation. It is, therefore, essential to protect it from the environment through the use of ceramic coatings. Adhesion between ceramic coatings and graphite is controlled by the mechanical stresses in the coatings and the thermodynamic work of adhesion. Different metal-graphite systems were examined which showed that the adhesion particularly depended on the thermal expansion coefficient mismatch between the two materials and on metal carbide stability. Thus, the role of the addition on the graphite surface of elements such as Cr, Mo, Al, Si, O on the adhesion of metals or ceramics to graphite has been identified.
NiCrAlY Coatings in YAG Laser Combined Low Pressure Plasma Spraying
Authors: Eguchi N. , Zhou Z. , Shirasawa H. , Ohmori A. 
Published: May 2021

Abstract
Densification of plasma-sprayed NiCrAlY coatings was studied from the viewpoint of hybrid spraying combined with YAG laser irradiation. The laser beam was varied while performing low pressure plasma hybrid spraying and the microstructure of each coating was examined and compared with a conventional plasma sprayed coating. Of the various hybrid spraying methods tested, simultaneous irradiation produced the hardest microstructure with the least amount of porosity. The characteristics of the microstructures observed in each coating are explained with respect to their thermal hysteresis behaviors.
Plasma Spraying of Functionally Graded ZrO2/NiCoCrAlY Coating System Using Composite Powders
Authors: Khor K.A. , Gu Y.W. , Dong Z.L. 
Published: May 2021

Abstract
Pre-alloyed and plasma spheroidized composite powders were used as the feed-stock in the plasma spraying of functionally graded ZrO2/NiCoCrAlY coatings. The ball milling parameters of the composite powders and the plasma spraying parameters for preparing FGM coatings were optimized in order to obtain the best performance for the thermal barrier coatings. Microstructure, physical, mechanical and thermal properties of ZrO2/NiCoCrAlY FGM coatings were investigated and compared with those of traditional duplex coatings. Results showed that the advantages of using prealloyed composite powders in plasma spraying were to ensure chemical homogeneity and promote uniform density along the graded layers. Microstructure observation showed the gradient distribution of ZrO2 and NiCoCrAlY phases in the coating and no clear interface was found between two adjacent different layers. Oxidation of elements in Ni alloy occurred during plasma spray and the so-formed Al2O3 and Cr2O3 combined with ZrO2 in a wide range of proportions. The bond strength of FGM coatings was about twice than that of the duplex coatings. Results also indicate that the thermal cycling resistance of FGM coating was much better than that of the duplex coating.
Thermal Shock Resistance of Plasma-Sprayed Ceramic Coatings With Two- and Three-Layers
Authors: Kweon Y.-G. , Kim H.-J. 
Published: May 2021

Abstract
Several plasma-sprayed ceramic coatings with two- and three-layers were characterized and tested for the application of cooling tube coatings at the steel making factory. Thermal cycling tests using a torch heating with compressed air cooling were carried out and characterized before and after the tests. The effects of bond coat as well as top coat were also studied. Possible failure mechanisms with low carbon steel substrate were assessed in term of microstructure, porosity, bond strength, thermal expansion coefficient, and the phase transformation. Finally, the results of field tests at the oxygen convert gas recovery system are also discussed.
Evaluation of Residual Stresses Within Plasma-Sprayed Zirconia (ZrO2-Y2O3 8%wt) Coatings
Authors: Baradel N. , Bianchi L. , Blein F. , Freslon A. , Jeandin M. , Ceretti M. , Lu J. 
Published: May 2021

Abstract
Thermal spraying induces stresses, which strongly influence thermomechanical properties of the deposits. To study both generation and influence of these stresses, various techniques could be used separately and/or concurrently. "In-situ" curvature, neutron diffraction and incremental hole drilling methods are often presented as complementary techniques. In this study, partially stabilized zirconia coatings, performed onto steel substrates at various spraying temperatures, have allowed to compare these three different methods.
Thermal Expansion Properties of Plasma-Sprayed Thick Coatings
Authors: Lee Y.-K. , Kim H.-J. , Chang R.-W. 
Published: May 2021

Abstract
The thermal expansion characteristics of plasma-sprayed coatings were investigated. The thermal expansion measurements were carried out up to 1200°C on thick coatings that were substrate free. The effects on the thermal expansion coefficients were studied in terms of composition, powder size, porosity, and the phase transformation. The relationships between the thermal shock resistance and the thermal expansion properties of the coatings are also discussed.
Design and Experiments of Graded Thermal Barrier Coatings by Plasma Sprayings
Authors: Ahn H. , Hong S.H. 
Published: May 2021

Abstract
Graded metal-to-ceramic coatings as thermal barrier coating (TBC) have been studied to improve the surface properties of the coating on high-temperature components. The atmospheric and low pressure plasma spray experiments are carried out with partially stabilized zirconia (YSZ and MSZ) and MCrAlY for mixing of functionally gradient materials. Especially, three-layer and five-layer graded TBCs are designed and produced to match gradually the material properties of a substrate and a top coating for reducing thermal stresses. A fully-saturated fractional factorial test is employed to determine optimum process conditions related to the thermal plasma generation, powder feeding, and substrate handling. Microstructural analysis using optical microscope and SEM, compositional analysis by XRD, bond strength test and thermal shock tests are carried out for material evaluation of fabricated TBCs. According to the results of material evaluation, the spray process is optimized for improving coating quality, and the proper raw materials are selected as a result of microstructural analysis. Especially, it is found that the durability and strain tolerance to thermal shock are remarkably increased by the gradation of TBCs and the improvement of graded TBC results from the fracture mechanism related to the vertical crack.
New Thermal Barrier Coating System for High Temperature Applications
Authors: Wilden J. , Wank M. , Steffens H.D. , Brune M. 
Published: May 2021

Abstract
This paper assesses the thermal shock resistance of ceria (CeO2) and YPSZ-CeO2 multilayer coatings produced by plasma and high velocity oxygen flame spraying. The HVOF coatings were denser and had higher oxygen content than the coatings that were plasma sprayed. Optical microscopy revealed that the plasma sprayed coatings had microcracks originating in certain phases, while the HVOF coatings had cracks (perpendicular to the surface) across the entire layer thickness. Based on thermal shock and bond strength testing, multilayer YPSZ-CeO2 coatings may be of practical value meriting further investigation.
Towards a Better Control of Thermal Spray Processes
Authors: Moreau C. 
Published: May 2021

Abstract
Developing and using efficient controls for thermal spray processes is essential to produce coatings in a more consistent manner day after day. This paper discussed the different approaches that can be used, today or in the future, to better control spray processes. The various steps or sub-processes involved in thermal spraying are first reviewed identifying the key parameters that can be monitored and controlled. An overview of current sensing techniques and those under development for probing the state of these key parameters will then be presented. Finally, different control approaches will be reviewed looking at the basic knowledge and models required to implement an efficient and intelligent control strategy for thermal spray processes.
AN ISLAMIC PERSPECTIVE ON PREVENTING SEXUAL ABUSE AGAINST CHILDREN
Authors: Nasimah Hussin  , Hanifah Haydar Ali Tajuddin  
Published: May 2021

Sexual abuse against children in Malaysia has been consistently on the rise. The Ministry of Women, Family and Community Development, Malaysia has stated that a total of 1,721 cases of sexual crimes against children were recorded in the first half of 2020. Most offenders in such cases were family members, guardians and those close to the children. This is an alarming number. Islam treats sexual abuse against children as a serious offence that must be strictly curbed. In Islam, any sexual activity out of wedlock is condemned and considered as a punishable act. It is even worse when the act is committed against the will of victim or it is committed against those who are physically and mentally weak as well as those whose consent is not yet valid such as children. This article discusses measures to prevent sexual abuse against children which are derived from the Shari`ah principles. It adopts a doctrinal study of existing primary and secondary materials relating to theories of victimization and methods to prevent criminal victimization against children from the Islamic perspectives. Hence, Shari’ah texts and juristic views on the relevant issues are essential to be analysed. The finding of this article confirms that Islam has a unique approach to deal with this issue and to even prevent the crime before it is committed. Islam suggests proactive steps that could be observed by individuals, guardians, the community as well as authorities concerned to ensure that the children are protected and do not become gullible victims.
Distal ventriculoperitoneal shunt catheter tightly coiled around the valve in the absence of a subgaleal cerebrospinal fluid collection: illustrative case
Authors: Tamura Goichiro , Vaughan Kerry A. , Breitbart Sara , Branson Helen M. , Ibrahim George M. 
Published: May 2021

BACKGROUND
Among the known complications of ventriculoperitoneal (VP) shunts, subcutaneous or subgaleal migration of distal catheters is rare. Prior case reports have proposed several risk factors, including inadequate fixation of the shunt device, presence of a large subgaleal space filled with cerebrospinal fluid (CSF), and repetitive flexion/extension movement of the head producing a “windlass effect.” Tight coiling of a distal catheter around the valve without a large subgaleal space has not been reported.

OBSERVATIONS
The patient was born prematurely and underwent VP shunt placement for posthemorrhagic ventricular dilatation at 3 months of age with reassuring postoperative imaging. At approximately 3 years of age, shunt radiography and head computed tomography unexpectedly showed excess tubing coiled extracranially around the shunt valve. The patient did not exhibit any clinical symptoms of shunt malfunction and underwent an uneventful revision of the VP shunt system. No CSF-filled subgaleal space was observed intraoperatively.

LESSONS
Distal catheter migration can occur without the clear presence of a subgaleal CSF collection and symptoms of acute hydrocephalus. Appropriate fixation of the shunt system using nonabsorbable stitches is recommended to prevent catheter migration caused by the windlass effect.
Subarachnoid hemorrhage due to intradural cerebral aneurysm and simultaneous spinal subdural hematoma: illustrative case
Authors: Hernández-Fernández Francisco , Cámara-González Noemí , Pedrosa-Jiménez María José , Alcahut-Rodríguez Cristian 
Published: May 2021

BACKGROUND
Spontaneous spinal subdural hematomas (SSDHs) are unusual. Among their probable etiologies, an association with ruptured brain aneurysms has been described in an extraordinary way. The underlying pathophysiological mechanism is not conclusively described in the literature.

OBSERVATIONS
The authors reported an exceptional case of a 59-year-old woman admitted for a condition that included sudden headache, stiff neck, and vomiting associated with pain in the left flank area that radiated to the leg. Computed tomography (CT) of the brain evidenced acute subarachnoid hemorrhage distributed in the bilateral posterior parieto-occipital fossa and occipital horns of the ventricles. CT angiography detected a dissecting aneurysm in the left vertebral artery (V4) that was treated urgently via the endovascular route. In the next hours, the patient’s symptoms worsened, with paraplegia of the lower extremities. Magnetic resonance imaging showed SSDH at T4–6 and extensive associated myelopathy.

LESSONS
The origin of the spinal hematoma may be the rupture of the aneurysm of the V4 segment in the dura mater of the foramen magnum and subsequent rostrocaudal migration of the hemorrhage to the spinal subdural space, enhanced by an intracranial pressure increase. This hypothesis is discussed, as is a brief literature review.
Endoscopic endonasal extreme far-medial approach for a lower clivus osteochondroma in a patient with hereditary multiple exostoses: illustrative case
Authors: Morinaga Yusuke , Akutsu Hiroyoshi , Kino Hiroyoshi , Tanaka Shuho , Miyamoto Hidetaka , Matsuda Masahide , Yasuda Muneyoshi , Ishikawa Eiichi 
Published: May 2021

BACKGROUND
The authors reported on the use of endoscopic endonasal surgery (EES) for clivus osteochondroma in a patient with hereditary multiple exostoses (HME), a rare pediatric disorder characterized by the formation of osteochondromas adjacent to the growth plates of the axial and appendicular skeletal elements.

OBSERVATIONS
A 26-year-old man with a family history of HME reported progressive hoarseness and dysphagia over the previous 6 months. He was referred to us after magnetic resonance imaging (MRI) showed a bone tumor in the lower clivus. MRI revealed tumor proliferation in the lower clivus and its extension to the bilateral occipital condyle and jugular tubercle. The hypoglossal canal and jugular foramen were encased on the right side, whereas the medulla oblongata was compressed. The tumor was subtotally resected with EES, and the brainstem was successfully decompressed. The pathological diagnosis was exostoses. Transient postoperative worsening of dysphagia improved within 1 month without other neurological deficits. The patient underwent posterior occipitoaxial fixation 3 months after EES to correct instability and local lateral tilt of the right atlanto-occipital joint.

LESSONS
The authors’ experience showed that EES is effective for resection of lower clivus osteochondromas, including the cartilaginous cap, and may improve clinical outcomes in patients with HME.