bluuebunny/crossref_metadata_2025 huggingface dataset:
New Powdered Silicide Materials for Thermal Spraying Process and Coatings on the Niobium Base Alloys
Authors: Terentieva V. , Bogatchkova O. , Cornu D.
Published: May 2021

The given article presents some results of the scientific research devoted to the development of a new class of scale-resistant powder materials of the Si-Ti-Mo-B system for thermal spraying and using these materials for the creation of heat-resistant coatings on the niobium base alloys by means of various methods of thermal spraying. Also under consideration are problems relating to the theory and practice of obtaining reliable protective coatings on high-melting metals and their alloys, niobium ones included, intended for operation in high-enthalpy oxygen-containing gas flows. Hazard in commencing an oxidation reaction of the base material under coating is connected with density of open pores and cracks, and partial pressure of the oxidizer. Powdered multicomponent heterophase materials for gas-thermal spraying of protective coating with a self-healing ability and controlled properties are proposed. Finally the results of some properties of new silicide-type heterophase powders containing silicide and boride phases for a thermal spraying process and some properties of protective coating deposited on the niobium base alloys by means of a thermal spraying technique are presented.
Molybdenum Disilicide Composites Produced by Plasma Spraying
Authors: Castro R.G. , Kung H. , Hollis K.J. , Bartlett A.H.
Published: May 2021

The intermetallic compound, molybdenum disilicide (MoSi2), is being considered for high temperature structural applications because of its high melting point and superior oxidation resistance at elevated temperatures. The lack of high temperature strength, creep resistance and low temperature ductility has hindered its progress for structural applications. Plasma spraying of coatings and structural components of MoSi2-based composites offers an exciting processing alternative to conventional powder processing methods due to superior flexibility and the ability to tailor properties. Laminate, discontinuous and in situ reinforced composites have been produced with secondary reinforcements of Ta, Al203, SiC, Si3N4 and Mo5Si3. Laminate composites, in particular, have been shown to improve the damage tolerance of MoSi2 during high temperature melting operations. A review of research which has been performed at Los Alamos National Laboratory on plasma spraying of MoSi2-based composites to improve low temperature fracture toughness, thermal shock resistance, high temperature strength and creep resistance will be discussed.
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

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

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

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

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 (< 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

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

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

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

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

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

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

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

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

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

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

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

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.
Phytoplankton diversity of a de-mineralized subtropical reservoir of Meghalaya state, northeast India
Authors: Sharma Bhushan Kumar , Sharma Sumita
Published: May 2021

This study monitors the spa-tio-temporal variations of phytoplankton of a soft-water and de-mineralized reservoir of Meghalaya state of northeast India. Phyto-plankton assemblages of the littoral and limnetic regions reveal total 36 species and diverse desmids, and con-tribute dominantly to net plankton abundance. Our results record the quantita-tive importance of Charo-phyta > Bacillariophyta > Dinophyta and Charophyta > Dinophyta, and the ‘spe-cialist’ nature of 11 and six species at the littoral and limnetic regions, respective-ly. Staurastrum spp. and Cosmarium spp. are notable taxa. Phytoplankton indi-cates moderate species di-versity and depicts domi-nance and evenness varia-tions. The individual abiotic factors exert differential in-fluence on various taxa at the two regions and the ca-nonical correspondence analysis registers 73.02 and 71.14% cumulative influ-ence of 10 abiotic factors on the littoral and limnetic as-semblages, respectively. The spatial differences of phytoplankton composition, richness, abundance, im-portant groups and taxa, specialist species, diversity indices and the influence of individual abiotic factors are hypothesised to habitat heterogeneity amongst the sampled regions. This study records notable temporal differences of phytoplank-ton richness, abundance, di-versity and the role of abiot-ic factors vis-a-vis the lim-ited survey of November 1990–October 1991.
Febrile Ulceronecrotic Mucha-Habermann Disease: A Rare Case Report and Review of Cases Treated With Oral Cyclosporine
Authors: Sooksamran Apasee , Sudtikoonaseth Poonnawis , Sajjachareonpong Praneet , Tienthavorn Tanongkiet
Published: May 2021

We present a case of febrile ulceronecrotic Mucha-Habermann disease who presented with widespread erythematous crusted papules, which rapidly progressed to ulceronecrotic lesions accompanied by fever. The serologies showed high titers of cytomegalovirus IgG (>1:3,200) and IgM (1:800). The histopathological study showed epidermal necrosis. The treatment was begun with systemic steroids and roxithromycin to which the patient did not respond. After switching the treatment to methotrexate, the patient was further complicated by getting hepatitis. Low dose cyclosporine resolved the situation within 2 weeks. In patients for whom methotrexate is contra-indicated or ineffective, cyclosporine can suppress T-lymphocyte hyperresponsiveness and resolve this disease.
Implikasi Yuridis Penetapan Covid-19 Sebagai Bencana Nasional Dalam Pelaksanaan Kontrak
Authors: Hidayat Muhammad Fajar , Sommaliagustina Desi
Published: May 2021

Corona Virus Disease 2019 atau COVID-19 telah ditetapkan Presiden Joko Widodo menjadi Bencana Nasional dengan Keputusan Presiden No. 12 Tahun 2020 tentang Penetapan Bencana Nonalam Penyebaran Corona Virus Disease 2019 (COVID-19) sebagai Bencana Nasional di Jakarta pada tanggal 13 April 2020. Presiden telah mengeluarkan Keppres 11 tahun 2020 tentang Penetapan Kedaruratan Kesehatan Masyarakat COVID-19. Penyebaran Corona Virus Disease 2019 (COVID-19) membawa dampak terhadap pertumbuhan perekonomian negatif secara global, termasuk dalam hal perikatan. Para pihak yang tidak bisa memenuhi prestasinya dalam sebuah perikatan dikarenakan pandemi covid-19 tidak serta merta diklasifikasikan kondisi pandemi covid-19 sebagai keadaan memaksa (overmacht atau force majeure). Harus dinilai secara kasus per kasus sesuai dengan situasi dan kondisi faktual yang terjadi. Terkecuali apabila para pihak dalam kontrak yang disepakati bersama para pihak telah menguraikan secara rinci tentang apa saja yang dikualifikasi sebagai force mejeure.
Penegakan Hukum Tindak Pidana Cukai Di Perbatasan Kawasan Perdagangan Dan Pelabuhan Bebas Bintan
Authors: Syahputra Irwandi , Danil Elwi , Adhayanto Oksep , Efritadewi Ayu
Published: May 2021

Part of the Tanjungpinang area is a free trade area and a free port. Placing some of these areas makes it difficult to supervise the traffic of goods, especially the excisable goods of the type of cigarettes, plus in the case of law enforcement, none of these excise crimes have been brought to court. Bintan free port. The method used in this research is sociological juridical method. Or what is known as empirical. Based on this research, it can be concluded that in law enforcement, the imposition of sanctions must pay attention to several things that become one unit, namely people's ignorance of the prohibited items, the number of items in a small number and not a repetition of the same criminal act. The granting of excise exemption quotas for excisable goods types of cigarettes for public consumption must be taken into account of the urgency of this.
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.
Evaluation of tortuous vertebral arteries before cervical spine surgery: illustrative case
Authors: Sarmiento J. Manuel , Cohen Justin D. , Babadjouni Robin M. , Quintero-Consuegra Miguel D. , Gonzalez Nestor R. , Perry Tiffany G.
Published: May 2021

BACKGROUND

Cervical spine surgery sometimes necessitates complex ventral/dorsal approaches or osteotomies that place the vertebral artery (VA) at risk of inadvertent injury. Tortuosity of the VA poses increased risk of vessel injury during anterior decompression or placement of posterior instrumentation.

OBSERVATIONS

In this report, the authors describe a patient with degenerative cervical spondylotic myelopathy and focal kyphotic deformity requiring corrective surgery via a combined ventral/dorsal approach. Computed tomography (CT) and CT angiography (CTA) of the spine identified a left medially enlarged C4 transverse foramen and tortuous VA V2 segment forming a potentially dangerous medial loop into the vertebral body, respectively. The patient’s presentation and management are described.

LESSONS

The course of the VA is variable, and a tortuous VA with significant medial or lateral displacement may be dangerous during ventral and dorsal approaches to the cervical spine. CTA of the cervical spine is warranted in cases in which atlantoaxial fixation is needed or suspicious transverse foramen morphology is identified to understand the course of the VA and identify anatomical variations that would put the VA at risk during cervical spine surgery.
STEM practices in Science teacher education curriculum: Perspectives from two secondary school teachers’ colleges in Zimbabwe
Authors: Mutseekwa Christopher
Published: May 2021

This study assessed how science, technology, engineering and mathematics (STEM) education is integrated in Science Teacher Education curriculum in Zimbabwe. An exploratory mixed methods research design, within the post-positivist paradigm, was used to guide the collection and analysis of data. Data were sourced from 18 Science teacher educators and 108 final year Science student teachers pooled from two secondary school Teachers’ Colleges through a semi-structured questionnaire, follow-up interviews, focus groups and documents. From the findings, it was evident that although a lot was done to promote STEM literacy in the two colleges, integration of STEM education and practices into the science education curriculum was coincidental rather than planned. Participation in Science exhibitions at local and national level that was common and increased enrolment of teacher candidates in STEM subjects was viewed as major ways to promote the initiative in the Teachers’ Colleges. However, support that targeted a teacher education STEM curriculum and integration/liaison with Engineering and industry was largely found lacking, suggesting the need for practices such as field-trips, work visits and partnerships that foster closer collaboration between colleges, schools, professional scientists and industry.
The Mathematical Proficiency Promoted by Mathematical Modelling
Authors: Corrêa Priscila Dias
Published: May 2021

This study aims to investigate the mathematical proficiency promoted by mathematical modelling tasks that require students to get involved in the processes of developing mathematical models, instead of just using known or given models. The research methodology is grounded on design-based research, and the classroom design framework is supported by complexity science underpinnings. The research intervention consists of high-school students, from a grade 11 mathematics course, aiming to solve four different modelling tasks in four distinct moments. Data was collected during the intervention from students’ written mathematical work and audio and video recordings, and from recall interviews after the intervention. Data analysis was conducted based on a model of mathematical proficiency and assisted by interpretive diagrams created for this research purpose. This research study offers insight into mathematics teaching by portraying how mathematical modelling tasks can be integrated into mathematics classes to promote students’ mathematical proficiency. The study discusses observed expressions and behaviours in students’ development of mathematical proficiency and suggests a relationship between mathematical modelling processes and the promotion of mathematical proficiency. The study also reveals that students develop mathematical proficiency, even when they do not come to full resolutions of modelling tasks, which emphasizes the relevance of learning processes, and not only of the products of these processes.
Do the Manager's Personal Features Influence the Verbal Tone Used in Conference Calls?
Authors: Ribeiro Lyra Andrea , Xavier Beiruth Aziz , Ramos Ferreira Felipe
Published: May 2021

The objective of this study is to evaluate whether managers’ tone of voice of Brazilian companies that publish the results in the presentation phase of the conference call is influenced by the personal characteristics of these agents. A total of 10 Brazilian companies were traded on the New York Stock Exchange (ADR) between 2002 and 2016, which made voluntary disclosure. The sample was limited to the companies with negotiations in North American market, that make the voluntary disclosure of the results by the necessity of the availability of the conference calls in English. To calculate the tone of voice, the dictionary developed by Loughran and McDonald (2011) was used. The tone was calculated based on the conference calls of quarterly disclosure of the results of the companies and related to the characteristics of the managers like gender, position and academic formation. The results verified in the Brazilian companies confirm the same ones found in international surveys, which find evidences that the personal characteristics influence the tone of voice used in the phase of presentation of the conference calls, controlling other factors like the performance of the company.
The Effectiveness of Mentoring in ELT Context
Authors: Ghanbari Abolfazl , Zare Fatemeh
Published: May 2021

In their beginning stages of learning, the teachers require more practical ideas on how to choose and behave effectively to be a successful teacher. Accordingly, the purpose of this study was to investigate the effectiveness of mentoring as a tool for aiding teachers’ development and teacher’s portfolio assessment of the teaching skills of Iranian ELT teachers. Classroom observation via a checklist and an interview was used to examine the effectiveness of mentoring in the Iranian ELT context. The findings indicated the effectiveness of mentoring in teachers' teaching skills and some of its shortcomings.
Proposta De Implementação De Melhoria Da Área De Marketing: Estudo De Caso Na Empresa De Coleta De Resíduos J.A Oliveira Peixoto – ME Em Manaus
Authors: Oliva Luiz Paulo de Verçosa , Oliva Paulo Francisco Paiva de , Gluck Wilhelm Braz , Roberto José Carlos Alves
Published: May 2021

O presente trabalho tem como objetivo elaborar um plano de implantação de melhoria da área de Marketing utilizando a ferramenta 5w2h dentro da Empresa J.A OLIVEIRA PEIXOTO- ME. Através desta ferramenta, encontramos como ponto crítico a divulgação da marca da empresa. Com as análises feitas e os resultados adquiridos, demos início a implantação de melhorias na área mais crítica identificada. As implantações de melhorias levaram em consideração a importância nos treinamentos de funcionários, implantação de ferramentas para melhoria do atendimento e melhoria dos preços e promoções tanto nos aluguéis dos equipamentos como nos serviços prestados aos clientes. Com cinco ações interventivas, observamos uma melhora na imagem da marca para os clientes e possíveis parceiros, que poderão contribuir com a empresa em seu ramo de negócios, melhorando, assim, os lucros da empresa em relação às mudanças. A melhoria do marketing da empresa, com estas metas sendo implantadas, demonstra o quanto a visibilidade da marca diante do mercado de Coleta de resíduos pode melhorar, trazendo lucros e benefícios dentro e fora da empresa. Concluímos que todas as etapas feitas, desde a pesquisa para encontrar os problemas até sua análise e implantação, para assim montarmos um melhor modo de ação interventiva com uma visão futura de lucratividade e claro que status mediante aos clientes que irão tornar a marca da empresa uma marca conhecida por suas qualidades no serviço, atendimento e até mesmo rapidez, mostrando assim, que de fato o marketing usado de forma adequada e certa pode, e é capaz de fazer uma empresa como J.A OLIVEIRA PEIXOTO- ME melhorar e mudar seus valores para melhor atendimento aos clientes e seus colaboradores.
Proposta De Implementação De Programas De Treinamento Para A Padronização Dos Processos Para A Melhoria Das Vendas: Estudo De Caso No Armarinho Facilita
Authors: Lima Emily Reis de , Lima Yasmin de Souza , Silva Carolina Barbosa da , Roberto José Carlos Alves
Published: May 2021

O presente artigo tem a finalidade de propor a implementação de programas de treinamento para a padronização dos processos para a melhoria de vendas do Armarinho Facilita localizado na cidade de Manaus/AM. Com base na pesquisa realizada na primeira etapa do diagnóstico, identificou-se que a área de logística é a mais crítica, pela falta de treinamento e padronização dos processos estabelecidos nas funções dos colaboradores. A pesquisa teve como objetivo a implementação de fatores para o melhor manuseio do estoque que possam beneficiar as vendas, já que nos objetivos específicos seriam identificar as principais causas da ineficiência do estoque, analisar as possibilidades de solução para a gestão do estoque compatíveis com o porte da empresa e propor a reestruturação das práticas de gestão do estoque. A metodologia aplicada na pesquisa quanto aos fins foi exploratória e explicativa, quantos aos meios a pesquisa foi de campo. A ferramenta da qualidade 5W2H foi utilizada para a proposta da implementação nas ações de melhorias indicadas: padronização dos processos, treinamentos voltados às vendas, organização do estoque para fácil manuseio, Plano de motivação e benefício e ferramental 5S. Com isso se espera o acompanhamento das ações de melhoria e responsabilidade de execução, tendo como resultado o aprimoramento da produtividade dos colaboradores através do treinamento de organização e técnicas de vendas, o aumento da motivação através das metas estabelecidas.
Methylphenidat: Ein Rückblick
Authors: Oliveira Vinicius Faustino Lima de , Moreira Danilo José Silva , Fonseca Juliana Brito da , Rossi Karoline , Vasconcelos Suzana dos Santos , Dias Claudio Alberto Gellis de Mattos , Oliveira Euzébio de , Dendasck Carla Viana , Araújo Maria Helena Mendonça de , Fecury Amanda Alves
Published: May 2021

Methylphenidat (MFD) ist ein Amphetamin-abgeleitetes Medikament, das das Zentrale Nervensystem (SNC) stimuliert und erhöhte Aufmerksamkeit, weniger Ablenkung und erhöhtes Gefühl der Motivation fördert. Diese Studie zielt darauf ab, die wichtigsten pharmazeutischen Eigenschaften von MFD zu beschreiben, die klinischen Indikationen für die Verwendung von MFD hervorzuheben und die möglichen unerwünschten Ereignisse, die sich aus dem Verbrauch von MFD ergeben, zu beschreiben. Dazu haben wir in den Datenbanken ScienceResearch.com, SciELO, LILACS, PubMed und EMBASE sowie in den institutionellen Repositories der Föderalen Universität von São Paulo, der Föderalen Universität Minas Gerais und der Föderalen Universität Ceará unter Verwendung der Schlüsselwörter und Assoziationen “Methylphenidat”, “Ritalin”, “Effekte” und “effects” recherchiert. Es wurde nachgewiesen, dass das Medikament aus einer racemischen Mischung besteht, die aus vier Stereoisomen gebildet wird, und der pharmakologisch aktive Wirkstoff ist Racemate Dextrogyl (d,l)-treo-MFD. Es wirkt auf die Blockade von Dopamin und Noradrenalin-Transporter aus dem ZNS, Förderung von Effekten, die seine Verschreibung rechtfertigen, um Aufmerksamkeitsdefizit-Hyperaktivitäts-Störung (TDAH) zu behandeln. In den letzten Jahren hat der Konsum für nichttherapeutische Zwecke zugenommen. Einige Nebenwirkungen seiner Verwendung wurden berichtet, und Schlaflosigkeit, Reizbarkeit und Kopfschmerzen wurden berichtet.
Metilfenidato: Una recensione
Authors: Oliveira Vinicius Faustino Lima de , Moreira Danilo José Silva , Fonseca Juliana Brito da , Rossi Karoline , Vasconcelos Suzana dos Santos , Dias Claudio Alberto Gellis de Mattos , Oliveira Euzébio de , Dendasck Carla Viana , Araújo Maria Helena Mendonça de , Fecury Amanda Alves
Published: May 2021

Il metilfenidato (MFD) è un medicinale derivato dalle anfetamine che stimola il Sistema Nervoso Centrale (SNC), promuovendo una maggiore attenzione, meno distrazione e un maggiore senso di motivazione. Questo studio ha lo scopo di descrivere le principali caratteristiche farmaceutiche della MFD, evidenziare le indicazioni cliniche per l’uso di MFD e dettagliare i possibili eventi avversi derivanti dal consumo di MFD. Per questo, abbiamo condotto una ricerca nei database ScienceResearch.com, SciELO, LILACS, PubMed ed EMBASE e nei repository istituzionali dell’Università Federale di São Paulo, dell’Università Federale di Minas Gerais e dell’Università Federale di Ceará, utilizzando le parole chiave e le associazioni “metilfenidato”, “ritalin”, “effetti” ed “effects“. È stato dimostrato che il farmaco consiste in una miscela racemica formata da quattro stereoisomeri, e il composto farmacologicamente attivo è racemato dextrogyl (d,l)-treo-MFD. Agisce sul blocco dei trasportatori di dopamina e noradrenalina dal SNC, promuovendo effetti che giustificano la sua prescrizione per trattare il disturbo da deficit di attenzione iperattività (TDAH). Negli ultimi anni, il suo consumo per scopi non terapeutici è aumentato. Sono stati riportati alcuni effetti avversi del suo uso e sono stati segnalati insonnia, irritabilità e mal di testa.
Metilfenidato: una revisione
Authors: Oliveira Vinicius Faustino Lima de , Moreira Danilo José Silva , Fonseca Juliana Brito da , Rossi Karoline , Vasconcelos Suzana dos Santos , Dias Claudio Alberto Gellis de Mattos , Oliveira Euzébio de , Dendasck Carla Viana , Araújo Maria Helena Mendonça de , Fecury Amanda Alves
Published: May 2021

Le méthylphénidate (MFD) est un médicament dérivé des amphétamines qui stimule le système nerveux central (SNC), favorisant une attention accrue, moins de distraction et un sens accru de la motivation. Cette étude vise à décrire les principales caractéristiques pharmaceutiques de la MFD, à mettre en évidence les indications cliniques pour l’utilisation de la MFD et à détailler les effets indésirables possibles découlant de la consommation de MFD. Pour cela, nous avons mené une recherche dans les bases de données ScienceResearch.com, SciELO, LILACS, PubMed et EMBASE et dans les référentiels institutionnels de l’Université fédérale de São Paulo, de l’Université fédérale du Minas Gerais et de l’Université fédérale de Ceará, en utilisant les mots clés et les associations « méthylphénidate », « ritalin », « effets » et « effects ». Il a été démontré que le médicament se compose d’un mélange racemic formé par quatre stereoisomers, et le composé pharmacologiquement actif est racemate dextrogyl (d,l)-treo-MFD. Il agit sur le blocus des transporteurs de dopamine et de noradrénaline du SNC, favorisant les effets qui justifient sa prescription pour traiter le trouble déficitaire de l’attention avec hyperactivité (TDAH). Ces dernières années, sa consommation à des fins non thérapeutiques a augmenté. Certains effets indésirables de son utilisation ont été rapportés, et l’insomnie, l’irritabilité et le mal de tête ont été rapportés.
Characterization of Yeast Strains with Ketoreductase Activity for Bioreduction of Ketones
Authors: Csuka Pál , Nagy-Győr László , Molnár Zsófia , Paizs Csaba , Bódai Viktória , Poppe László
Published: May 2021

This study describes six yeast strains for stereoselective ketone reductions. The reaction conditions for the yeast strains (Pichia carsonii, Lodderomyces elongisporus, Candida norvegica, Candida guillermondi, Debaromyces fabryi and Candida parapsilosis) were optimized in a design of experiments for three ketones of different properties. The pH tolerance, temperature stability and productivity of the bioreductions with lyophilized cells of the yeast strains were characterized. In several cases, the optimized bioreductions resulted in enantiopure alcohols (ee > 99 %) with conversions ranging from moderate to excellent.
ANALISIS PRODUKTIVITAS TENAGA KERJA PADA PEKERJAAN PASANGAN BATA PERUMAHAN TIPE 36 (Studi Kasus pada Perumahan Griya Putri Tanjung Kota Bengkulu)
Authors: Yulianty Chindy , Supriani Fepy , Gunawan Agustin
Published: May 2021

The process of housing development is inseparable from labor productivity. This study aimed to determine the value of LUR (Labor Utilization Rate), workgroup productivity, and dominant factors that influence the masonry work in Griya Putri Tanjung Housing. The method used in the research was field observations for six houses by observing the effective work time, contribution work time, and ineffective work time, calculating the area of bricklaying and questionnaires to 12 workers. The questionnaires were processed with SPSS 24. The results obtained showed that the highest worker utility factor (LUR) was on day 2 of 88.89%. The Average LUR in Putri Tanjung Griya Housing is greater than 50%, so the work utility factor reaches the effective time. The highest average productivity of each workforce is on the 3rd day by a productivity value of 1.51 m2/hour/person. The most dominant factor was the time factor and implementation conditions (up to 82%), then the physical factor of labor (32,8%), managerial (-24,1%), the background of the employee (19,1%). The lowest factor was the group factor and the expertise of the workforce by a percentage of influence of         -17,5%. Keywords: housing, labor, bricklaying.