bluuebunny/crossref_metadata_2025 huggingface dataset:
Solving no-wait two-stage flexible flow shop scheduling problem with unrelated parallel machines and rework time by the adjusted discrete Multi Objective Invasive Weed Optimization and fuzzy dominance approach
Authors: Jafarzadeh Hassan , Moradinasab Nazanin , Gerami Ali
Published: November 2017

Purpose: Adjusted discrete Multi-Objective Invasive Weed Optimization (DMOIWO) algorithm, which uses fuzzy dominant approach for ordering, has been proposed to solve No-wait two-stage flexible flow shop scheduling problem.Design/methodology/approach: No-wait two-stage flexible flow shop scheduling problem by considering sequence-dependent setup times and probable rework in both stations, different ready times for all jobs and rework times for both stations as well as unrelated parallel machines with regards to the simultaneous minimization of maximum job completion time and average latency functions have been investigated in a multi-objective manner. In this study, the parameter setting has been carried out using Taguchi Method based on the quality indicator for beater performance of the algorithm.Findings: The results of this algorithm have been compared with those of conventional, multi-objective algorithms to show the better performance of the proposed algorithm. The results clearly indicated the greater performance of the proposed algorithm.Originality/value: This study provides an efficient method for solving multi objective no-wait two-stage flexible flow shop scheduling problem by considering sequence-dependent setup times, probable rework in both stations, different ready times for all jobs, rework times for both stations and unrelated parallel machines which are the real constraints.
Using Social Media to Support Clinical Education
Authors: Jackson Jennifer
Published: November 2017

Social media has been used increasingly as part of nursing education. Nurse educators at a large, multisite teaching hospital used social media to support clinical teaching. A series of educational images was created by nurse educators and shared across Facebook, Twitter, and Instagram. This campaign coincided with in-unit clinical education. Nurse educators can consider using social media as an adjunct to clinical teaching, especially in large hospital settings.

J Contin Educ Nurs.
2017;48(12):541–542.
Simultaneous Novel Mutations of LRP5 and TSPAN12 in a Case of Familial Exudative Vitreoretinopathy
Authors: Kramer Gregory D. , Say Emil Anthony T. , Shields Carol L.
Published: November 2017

Familial exudative vitreoretinopathy and osteoporosis pseudoglioma syndrome are conditions that result from mutations in the LRP5 gene. Persistent fetal vasculature is a rare congenital malformation that can mimic end-stage familial exudative vitreoretinopathy. The authors report a case of familial exudative vitreoretinopathy in the spectrum of osteoporosis pseudoglioma syndrome associated with novel mutations of the LRP5 and TSPAN12 genes that resulted in a phenotype similar to bilateral persistent fetal vasculature. Both conditions can result in bilateral early-onset blindness. A high index of suspicion, dilated fundus examination and angiography of the parents, and genetic testing are necessary to ensure a correct diagnosis.

[
J Pediatr Ophthalmol Strabismus.
2016;53:e1–e5.]
Síntesis, caracterización y evaluación de la resistencia a la corrosión de recubrimientos híbridos Sol-Gel base TEOS/MPS sobre la aleación AA2050-T8
Authors: Nieves Claudia , Remolina Erika N. , Hernández Carlos A. , Rueda Laura M. , Coy Ana E. , Viejo Fernando
Published: November 2017

El presente trabajo tuvo como objetivo sintetizar, caracterizar y evaluar la resistencia a la corrosión de recubrimientos híbridos sol-gel base TEOS/MPS, sintetizados sobre la aleación AA2050-T8 (Al-Cu-Li) bajo diferentes condiciones experimentales de polimerización, tales como solvente y tiempo de envejecimiento, así como diferentes relaciones molares de los precursores inorgánico tetraetoxisilano (TEOS) e híbrido 3-metacriloxipropiltrimetoxisilano (MPS). Se monitoreó la evolución de los soles durante el proceso de envejecimiento mediante espectroscopía infrarroja (FT-IR) y ensayos reológicos. Los recubrimientos se obtuvieron mediante dip-coating y fueron caracterizados a través de microscopía electrónica de barrido (MEB-EDX). La evaluación de la resistencia a la corrosión se realizó mediante ensayos de polarización anódica potenciodinámica, en solución aireada 0,1 M de NaCl. Los resultados obtenidos revelaron que, de los tres solventes evaluados, el etanol es el que permite mejor estabilización del precursor híbrido y favorece el proceso de polimerización de los grupos metacrilato del precursor MPS. Por otra parte, la variación de la relación molar TEOS:MPS conlleva a la obtención de recubrimientos más homogéneos y continuos al incrementar la relación del precursor inorgánico. Finalmente, todos los recubrimientos sintetizados mejoraron la resistencia a la corrosión de la aleación AA2050-T8, en especial los sintetizados bajo la relación TEOS:MPS 80:20.
A Survey on Trend, Opportunities and Challenges of mHealth Apps
Authors: Jusoh Shaidah
Published: November 2017

Advancement of mobile technologies such as smartphones and PC tablets has given a great impact on healthcare systems. The mobile technology offers innovative approaches to addressing complex health concerns. Many mobile health applications (mHealth apps) are currently available on marketplaces. These apps are designed to facilitate various health issues and problems, and are intended to be used outside clinics.  However, very little research has been conducted to address trend, opportunities, and challenging issues of the apps. The purpose of this study is to investigate the current state of mHealth. A literature survey was conducted. Major findings of this study include, smartphones will be the major platform for mHealth apps, the number of published software is much higher than published scientific research, current mHealth apps lacking in grounded based theory and evaluation, and security and usability issues are still vulnerable. The findings suggest that involvement of all healthcare stakeholders is critical to the success of mHealth apps.
The Use and Effects of Smartphones in Higher Education
Authors: Alfawareh Hejab Maazer , Jusoh Shaidah
Published: November 2017

The purpose of this study is to investigate the use and effects of smartphones on academic staffs at a university level, especially in the Kingdom of Saudi Arabia. We conducted a survey study using questionnaires. The questionnaires were randomly distributed to 66 academic staffs who own a smartphone at the Northern Border University. This study discovers the smartphone had replaced a computer, and an email application was mostly used. The academic staffs also had utilized smartphone as a means for knowledge sharing. Social media applications were greatly used in teaching and learning. Despite the benefits of smartphone use, academic staffs had been negatively affected.  This study also reveals that having a smartphone diverted academic staffs' focus at work, created "check habits", and an artificial relationship; more than 90% of the respondents admitted that they put their smartphone besides their bed before sleep, and 61.41% of them claimed that they had the feelings of incompleteness whenever smartphones were not with them. 
Anciens entrepôts urbains de Bruxelles : architecture et construction
Authors: De Fossé Marianne
Published: November 2017

Les anciens entrepôts urbains sont de remarquables édifices. Or, malgré leur robustesse architecturale, ils constituent aujourd’hui un fragile patrimoine menacé de démolition. Les recherches actuellement menées à la Vrije Universiteit Brussel (VUB) s’attachent à accroître les connaissances relatives à l’architecture, au fonctionnement et à la construction des entrepôts d’Anvers, de Bruxelles et de Gand, ainsi qu’à leur intégration dans le tissu urbain, afin de favoriser leur sauvegarde et leur réutilisation respectueuse après adaptation. Le présent article expose les résultats d’un examen approfondi de documents d’archives et d’études inédites sur le terrain, portant sur des entrepôts du XIXe et du XXe siècles situés dans le centre historique de Bruxelles, là où furent implantées les premières zones industrielles aux alentours de la Senne et des quais. L’enquête réalisée sur 80 bâtiments démolis et existants s’intéresse d’abord à l’entreposage de différentes marchandises très représentées, à savoir, le foin, le bois d’œuvre, la bière et le textile. Il apparaît qu’à chacune de ces quatre marchandises correspond un type d’entrepôt distinct en termes d’architecture, d’organisation, de construction et d’intégration urbanistique.
Some Aspects of Energy Efficient Project Management
Authors: Trehub Mykola , Tiukhmenova Kseniia , Kravchenko Kostiantyn
Published: November 2017

According to energy-saving trends the use of all types of energy should be minimal and efficient. Since late 90-s such strategy has been already used in well-developed countries. In Ukraine the energy-saving measures became popular since 2014. Now it is possible to receive warm loans supported by Ukrainian government for private households and co-owners of multi-apartment buildings. Also, it is possible to apply for grants of the Ministry of Regional Development, Construction and Housing and Communal Services of Ukraine – the regional development projects that can be implemented at the expense of the state budget received from the European Union or other grants financed by local authorities at different levels. According to statistics it was found that using thermal sanitation method as a key measure of energy saving, it is possible to provide 85% of insulation efficiency. The research is focused on determination of weaknesses concerning grants for energy efficiency, their application and management. One of the most important factor that influence overall success is the correct calculation of energy losses. Three possible types of errors during calculations and possibilities to reduce their influence were defined. At the end of the article conclusions and suggestions for further research were made.
Heat Exchange and Unsaturated-Saturated Flow in Porous Media
Authors: Kačur Jozef , Mihala Patrik , Tóth Michal
Published: November 2017

We discuss the numerical modeling of heat exchange between the infiltrated water and porous media matrix. An unsaturated-saturated flow is considered with boundary conditions reflecting the external driven forces. The developed numerical method is efficient and can be used for solving the inverse problems concerning determination of transmission coefficients for heat energy exchange inside and also on the boundary of porous media. Numerical experiments support our method.
Metallurgists’ Insights on Diffusion-Assisted Dissimilar-Joints of Light- and Heavy-Alloys
Authors: Thirunavukarasu Gopinath , Kundu Sukumar , Chatterjee Subrata
Published: November 2017

In metallurgy and materials engineering, a number of phase transformation in solids like precipitation, oxidation, creep, annealing, homogenization, etc. are brought about by the process of diffusion. Many industrial manufacturing processes utilize solid-state diffusion principle, to name a few: 1. Rotating or sliding parts of steel have a hard outside case for wear resistance and a tough inner core for fracture resistance by gas carburizing procedure; 2. Integrated circuits were produced by diffusing impurity into silicon wafers; and 3. Joints between similar and dissimilar metals, alloys, and non-metals, were made using diffusion bonding (DB) technique. Day by day, the science of solid-state diffusion phenomenon is spreading inevitably into new areas of engineering and technology. Diffusion-Assisted-Joints (DAJs) meet the requirements for most critical structures in terms of strength, toughness, tightness, and resistance to heat and corrosion. DAJs can be made out of 730 pairs of dissimilar metals. Hence, DB is considered as an engineering marvel among all the physical welding metallurgists. Herein, experiments were performed to exactly map the quantum influence of the bonding temperature variation on the dissimilar joints of a popular light alloy, Ti-6Al-4V (TiA), and a heavily used heavy alloy, stainless steel (SS), using diffusion mechanism in high-vacuum environment. Cu foil (~200μm) was used as an interlayer. Necessary characterization tools for metallurgical investigations were used to understand the extent of diffusion along the TiA/Cu and Cu/SS interfaces, room-temperature mechanical properties, fracture morphologies, and fracture path of the TiA/Cu/SS DAJs. This paper discussed rational reasons backing the results of the characterizations.
Phase Transformations and Recrystallization in Cold-Rolled Al-Mg-Sc-Zr Alloy Prepared by Powder Metallurgy
Authors: Vlach Martin , Smola Bohumil , Stulikova Ivana , Kodetova Veronika , Kudrnova Hana , Malek Jaroslav , Ocenasek Vladivoj
Published: November 2017

The mechanical, thermal and electrical properties and recrystallization behaviour of the cold-rolled AlMgScZr alloy prepared by powder metallurgy were studied. The materials were investigated during isothermal annealing (400 and 550 °C) and during step-by-step linear annealing from room temperature up to 570 °C. The observed results were compared with microstructure observation by transmission electron microscopy and electron diffraction from a previous study of the Al–Mg-based alloys with Sc and Zr. The precipitation sequence of the Al–Mg system and coarsening of the Sc,Zr-containing particles caused electrical and heat flow changes during the annealing. The presence of the Al3(Sc,Zr) particles has an anti-recrystallization effect that prevents recrystallization at temperature minimally up to ~ 400 °C. A partial recrystallization of the alloy was registered after annealing at 550 °C already for 30 min. The cause of the anti-recrystallization effect is precipitation of the Mg-containing particles as follows from a comparison to the alloy without Mg. But the Mg-addition to the Al–Sc–Zr alloy prepared by powder metallurgy has a poorer anti-recrystallization effect than a Mn-addition.
Grain Boundary Wetting in the Nd-Fe-B-Based Alloy
Authors: Mazilkin Andrey , Straumal Boris , Protasova Svetlana , Baretzky Brigitte
Published: November 2017

The microstructure of Nd–Fe–B-based liquid-phase sintered alloy has been studied. The Nd2Fe14B/Nd2Fe14B GBs can be pseudo-incompletely (or pseudo-partially) wetted by the Nd-rich melt. Such GBs form the non-zero contact angle with the melt in the triple junctions and contain the uniformly thin (7-10 nm) Nd-rich layer. Such GBs are different from the completely wetted as well as from partially wetted GBs. Most probably, such thin Nd-rich GB layers are responsible for the excellent magnetic properties of the NdFeB-base permanent magnets because these GB layers ensure the magnetic isolation between the Nd2Fe14B grains needed for the high coercivity.
Investigation of the Bubble Effect in Lightweight PMMA Polymer
Authors: Bel T. , Cakar H. , Yahya Noorhana , Arslan C. , Baydogan N.
Published: November 2017

The modification of PMMA materials was provided by the application of a suitable degass process to obtain the porous structure. The application of a suitable degass process has enhanced the affordable weight reduction. The gamma transmission technique was used in order to examine the details on high precision processing and fabrication of the modified PMMA polymer as the affordable weight reduction of PMMA polymer supported for their use in high-volume vehicles and components.
Transient Liquid Diffusion Bonding of AISI304 Stainless Steel with a Nickel Base Interlayer
Authors: Jamshidi Lamjiri R. , Ekrami A.
Published: November 2017

AISI304 stainless steel was bonded by a nickel base interlayer, using a TLP bonding method at 1150 °C with different holding times. The microstructure of the joint region was studied by optical and scanning electron microscopes. The results showed that 20 minutes holding time is sufficient for complete isothermal solidification. At the bonding times of 4, 10, 15 minutes, a eutectic structure was formed at the joint region. The distribution of alloying elements within the joint region and diffusion affected zone were detected using EDS. The results showed that the eutectic microstructure consists of Fe and Cr borides and the isothermal solidified zone consists of solid solution of Fe and Ni at the bonding temperature. Samples with complete isothermal solidified joint were homogenized at 950°C for different times from 30 to 360 minutes to study the distribution of alloying elements between joint region and parent alloy. The results showed more uniform distribution of alloying elements with increasing the homogenization time due to the diffusion of alloying elements between the joint region and the parent alloys. Microhardness and shear strength of joined samples were measured and compared to that of the parent alloy at the same heat treatment condition. The joint shear strength of TLP bonded samples was about 82% that of the parent alloy at the homogenization time of 180 minutes.
Motion Equations of Helium Atom through Ordered and Disordered Quartz Structure
Authors: Kalashnikov Evgenii , Tolstikhin Igor , Krylova Nadezhda
Published: November 2017

In order to describe helium atom motion through the disordered quartz structure the local chain approach is used. The number of local chains equals the number of nearest neighbours (i.e., the closest atoms to those selected). Each local chain includes a He-atom. Transition of a He-atom from its site to a neighbouring one generates a space-periodical field, which acts on the He-atom. This could take place in both cases, if (1) the local order is preserved, or (2) the local order is changed. The last situation means that the structure element of quartz, SiO4 , is removed / added with respect to a He-atom. Distortion of the local order creates a defect of the order and means appearance of an additional average field, which is proportional to the internal “surface” of the defect. The above approach shows that the problem of He-atom motion through the disordered quartz structure can be reduced to “a local version” of the Frenkel-Kontorova model.
Application of Metallography in Solving of Manufacturing Defects of Galvanically Plated Polymers
Authors: Podzimek Petr , Andršová Zuzana , Kejzlar Pavel
Published: November 2017

Galvanic plating of polymeric structural parts is widely used in many industrial branches, e.g. in automotive. Minor errors in their manufacturing process are responsible for presence of surface defects. These defects, especially in the case of visual and decorative parts, are unacceptable. This paper demonstrates the usage of metallography to reveal and solve common problems in industrial production. Different types of galvanic plating defects on injection molded parts made of ABS, PC/ABS and PA manifest themselves by different ways.
The Use of Metallography for Examination of Causes of Surface Defects on Visual Parts
Authors: Andršová Zuzana , Kejzlar Pavel
Published: November 2017

Many of currently manufactured components intended for automotive, must not only meet the requirements on functionality, but also considerable demands on the visual appearance. Parts are subjected to thorough inspection and suppliers are forced to deal with causes of a very slight visual defects. When examining the defects, it is necessary to use a whole range of advanced analytical methods and procedures previously used only for identification of the physical and chemical properties and structure of the material. This paper deals with several examples which have been solved. It focuses especially on the use of demanding metallographic sample preparation from components with surface defects, examining the defects on the cross-section using mainly microscopic techniques and determining the causes of their generation. These results then serve as a basis for modification of the technology and thus they are the tool for significant reduction of amount of NOK parts.
Influence of Microstructure on Machinability of Material and its Final Surface Quality
Authors: Pavloušková Zina , Horynová Miroslava , Klakurková Lenka , Juliš Martin , Gejdoš Pavel , Remešová Michaela
Published: November 2017

Mechanical properties, such as hardness, yield strength and tensile strength, are very often considered as the only key factor for selecting technological parameters of materials machining. Analysis of the microstructure and specific microstructural parameters is not performed until serious problems occur during otherwise common machining processes. This study reports a few case studies, dealing with such problematics, which resulted from underestimation of the knowledge of macrostructure and microstructure of material. It deals with problems such as uncommon surface defects after machining or impossibility to use current technological machining processes when machining new batch of material.
Influence of the Surface Condition of Specimens on the Size of Coherently Diffracting Domains
Authors: Klečka Jakub , Lukáč František , Dudr Martin
Published: November 2017

Metallic sample preparation process from cutting to polishing introduces defects into the subsurface layers by plastic deformation. Methods of bulk sample characterization are usually sensitive to the microstructure and presence of defects e.g. dislocations, grain boundaries, etc. near the surface. The X-ray diffraction technique (XRD) is a unique method used primarily for phase identification and quantification of crystalline materials. The extending of the method by the whole pattern fitting using Rietveld refinement analysis enables also utilisation for other purposes such as determination of the size of coherently diffracting domains (CDD). This property quantifies the degree of disorder in material and is usually correlated with mean crystallite size, i.e. subgrain size. However, since the penetration depth of the laboratory X-ray radiation is limited to the order of tens of micrometers (depending on the material), the observed result is highly affected by the density of defects such as dislocations in the surface area of the specimen and thus by their surface condition. The effect of the different final steps of grinding and polishing on the observed size of CDD was studied and discussed for two materials - aluminum Al7075 alloy and high entropy alloy HfNbTaTiZr. The reasonable finishing for the optimal results was found for both materials.
Evaluation of Titanium Carbonitride Particles Using Image Analysis and Assessment of their Impact on Machinability
Authors: Martínek Petr , Míšková Jana , Sláma Peter
Published: November 2017

A car manufacturer makes crankshafts of materials from various suppliers. The steels from individual batches differed in their grinding behaviour, despite being supplied as a single steel grade. Some deliveries were repeatedly associated with much faster wear of grinding wheels than others. Consequently, the ground surfaces of the crankshafts developed visible patterns and, in some cases, surface cracks. The excessive wear in grinding wheels was suspected to be caused by titanium precipitates. The purpose of this investigation was to identify the phases in which titanium is present in the steels, describe the morphology, sizes and distribution of their particles and compare these aspects for materials from the three suppliers. It was found that titanium was present in the form of carbides or carbonitrides, whose morphology, sizes, distributions and quantities of particles varied greatly between the suppliers. These variations were identified as the cause of the differences in grinding behaviour.
Evaluation of Surface Degradation of Deoxidized AW-AlMg0.7Si Alloy
Authors: Horynová Miroslava , Remešová Michaela , Klakurková Lenka , Juliš Martin , Gejdoš Pavel , Páleníková Lucie
Published: November 2017

Corrosion of aluminium alloys due to chlorides is not rare in industrial practice. When detected, it is necessary to decide whether and how to remove the corroded areas and also to find the appropriate method for protection against further degradation. Appearance and quality of final surface is key factor in such cases. This study deals with final surface quality of aluminium alloy components and the extent of degradation after corrosion attack and subsequent chemical surface cleaning. Two AW-AlMg0.7Si alloy pipes, fabricated by two individual producers, were analyzed in order to reveal extent of atmospheric corrosion after the storage in the industrial area. Further analysis evaluated the influence of such degradation on final surface quality after surface cleaning by chemical way, using two different methods, namely deoxidizing and subsequent passivation. Special attention was paid to the influence of initial surface roughness on quality of final surface.
Analysis of Corrosion Attack on Kaplan Turbine Blades
Authors: Horník Jakub , Zuna Petr , Zoubek Michal , Svobodová Marie , Chmela Tomáš
Published: November 2017

The problematic of pitting corrosion on blades of Kaplan turbine is discussed. Corrosion behaviour was observed during the first year of service. Material of the water turbine blades is martensitic stainless steel GX4CrNi13-4. Chemical composition and hardness of blades was measured, EDS analysis of corrosion products and microstructural evaluation on replicas were carried out. The main problem was found in heterogeneities in the cast microstructure and local disproportions in chemical composition. Influence of microbiologically induced corrosion and surface roughness is considered.
The Analysis of Causes of Pressure Bottles Heads Destruction
Authors: Švec Martin , Kejzlar Pavel
Published: November 2017

The research deals with the cause of destruction of pressure bottles heads during ordinary operation. The scanning electron microscope (SEM) equipped with an energy dispersive detector (EDX) for local chemical analysis was used for material investigation. The analysis revealed selected oxidation penetrating deep into the material causing the loss of cohesion of phase boundaries leading to brittle fracture.
Development of Creep Damage in Similar Weld Joints of P92 Steel Pipe
Authors: Král Petr , Sklenička Václav , Kuchařová Květa , Svobodová Marie , Kvapilová Marie , Dvořák Jiří
Published: November 2017

The microstructure and creep behaviour of the welded joints of P92 steel pipe were investigated in order to determine the influence of orbital heat welding technology on the creep resistance. Creep specimens were machined from the welded joints. Tensile creep tests of welded joints were performed at 873 K using different stresses. The microstructure of tested specimens was investigated by scanning electron microscope Tescan equipped with an electron-back scatter diffraction. The creep results showed that the creep fracture strain of the welded joints decreases with decreasing value of applied stress. Microstructure investigation showed that fracture behaviour of welded joints is influenced by an enhanced cavity formation at grain boundaries in the heat-affected zone causing lower fracture ductility.
The Analysis of Causes of the Damage of a Turbine Blade Made of Ti-6Al-4V Alloy
Authors: Krčil Jan , Holec Jan , Horník Jakub , Hájková Pavlína , Čižmárová Elena , Mára Vladimír
Published: November 2017

The main causes of the damage of a compressor’s turbine blade are documented and described in the article. The turbine blade was made from titanium alloy grade 5 (VT6, Ti-6Al-4V). The analysed segments of the turbine blade were damaged by corrosion and erosion. The sample from the damaged blade was compared with an undamaged reference sample. The observed substantial distinctions between microstructure of the damaged and the reference sample were found using of light and scanning electron microscopy. The observed distinctions of the microstructure were caused by the differences in the heat treatment process.
Al-Fe Chips Processed by High-Energy Ball Milling and Spark Plasma Sintering
Authors: Kučera Vojtěch , Prusa Filip , Vojtěch Dalibor
Published: November 2017

Typically, conventional casting technologies are employed to manufacture aluminium alloys from scrap, but during recycling iron accumulates and increases in content. Increased iron content in such alloys reduces their mechanical properties. Because powder metallurgy is able to prepare materials with a very fine microstructure, we investigated its use for the preparation of aluminium alloys with a high iron content and the required mechanical properties. We prepared an Al-Fe17 (wt. %) binary alloy using combination of mechanical working (MW), high-energy ball milling (HEBM) and spark plasma sintering (SPS). The thus-prepared samples were analyzed (XRD, XRF, SEM-EDS, compression stress-strain test) and compared to the commercially-available alloy Al-Si12-Cu1-Mg1-Ni1, which is thermally stable. While the MW followed by SPS sample showed improved plastic deformation, the combination of MW, HEBM and SPS led to the absence of plastic deformation at room temperature. However, the MW+HEBM+SPS had much higher strength (579 MPa) and possessed similar thermal stability as the commercial Al-Si12-Cu1-Mg1-Ni1.
The Effect of Solution Treatment Temperature on Plastic Deformation and Fracture Mechanisms of Beta-Titanium Alloy
Authors: Malek Jaroslav , Hnilica František , Bartáková Sonia , Veselý Jaroslav
Published: November 2017

The beta-titanium alloys are used mainly in bioapplications for artificial joints and other implants. They posses interesting properties such as, high corrosion resistance, low Young’s modulus, good plasticity or superelasticity etc. In this work the effect of solution treatment temperature on deformation and fracture properties has been studied. The alloy Ti-35Nb-2Zr was processed via powder metallurgy process (cold isostatic pressing, sintering and subsequent swaging). Swaged alloy was annealed at 800, 850, 900, 950 and 1000 °C. Tensile tests have been performed on such heat treated specimens and the fracture surface has been studied in correlation with microstructure. With increasing annealing temperature both tensile strength (from 925 MPa to 990 MPa) and elongation (from 13 to 25 %) increased where the maximum values were obtained for 900 °C annealed specimens and subsequently slight decrease has been observed. The simultaneous increase of strength and elongation was attached to change of deformation mechanisms which was described by studying fracture surfaces and microstructure of deformed (tensile tested) specimens.
Influence of Mechanical Stress at High Temperatures on the Properties of Steels Intended for the Manufacture of Fuel Cladding for Generation IV Reactors
Authors: Špirit Zbyněk , Chocholoušek Michal , Šíma Marek
Published: November 2017

This paper describes the testing of thin-walled tubes made of oxide dispersion-hardened steels based on yttrium oxides. Series of mechanical and metallographic tests were carried out on the steels to evaluate the basic material properties. These steels are the candidate materials for the manufacture of the fuel cladding for generation IV nuclear reactors. Mechanical tests were performed on miniature specimens of Fe-9Cr and Fe-14Cr steels at 20 °C, 500 °C, and 625 °C under vacuum. Metallographic, fractographic and EBSD analyses were used to describe microstructure and fracture mechanism of the tested materials.
The Effect of Isothermal Hold Temperature on Microstructure and Mechanical Properties of TRIP Steel
Authors: Kučerová Ludmila , Bystrianský Martin , Káňa Josef
Published: November 2017

TRIP (transformation induced plasticity) steels are low alloyed low carbon steels with complex microstructures consisting of ferrite, bainite and retained austenite. This complex microstructure provides them with excellent strength to ductility balance, making them a member of advanced high strength steels (AHSS) group. Suitable microstructure can be obtained by either heat or thermo-mechanical treatment. A hold in bainite transformation region is an integral part of any form of commercial TRIP steel processing route, as it enables formation of sufficient volume fraction of bainite and also stabilization of retained austenite in the final microstructure. Various bainitic hold temperatures ranging from 350 °C to 500 °C were tested within thermo-mechanical treatment of 0.2C-1.5Mn-0.6S-1.5Al steel and the final microstructures were evaluated with regard to the suitability to TRIP effect and achieved mechanical properties. The microstructures were analyzed by scanning electron microscopy and mechanical properties measured by tensile test.
Characterization of Microstructure of Hadfield Steel
Authors: Průcha Vojtěch , Jansa Zdeněk , Šimeček Jiří , Žďánský Ondřej , Kříž Antonín
Published: November 2017

In this contribution, the preparation of metallographic sections and characterization of the microstructure of manganese Hadfield steels are discussed. The purpose of this paper is to provide information relevant to microstructural characterization of these steels. This type of steel is characterized by high resistance to abrasive wear, which is provided by surface strengthening through strain-induced martensitic transformation. Strengthening complicates the preparation of metallographic sections because the final microstructure can be influenced by the process and it can be eventually misinterpreted. Great attention must be paid to the choice of the etchant and the etching procedure. This contribution describes the entire metallographic characterization procedure, including the evaluation of grain size, micro-cleanness and presence of carbides on grain boundaries. It provides information for manufacturers and those, whose process and examine Hadfield steels with respect to their processing routes, wear resistance, non-magnetic properties and other aspects.
Failures of Engineering Structures Caused by Weld Imperfections
Authors: Mára Vladimír , Horník Jakub , Čižmárová Elena , Krčil Jan , Hájková Pavlína
Published: November 2017

The problematic of welding in terms of weld quality in dependence on service life of mechanical structures is discussed. Some examples of inadequate quality weld joints causing failure under load are described. Materials of the evaluated welds were following: S355 steel and Inconel 635 super alloy. Service conditions of homogeneous welds were different for both materials and weld quality was covered by Welding Procedure Specification. Using metallographic evaluation, the main problems were detected in a form of geometrical imperfections or insufficient penetration. These existing imperfections combined with static and dynamic load initiate the partial malfunction or failure of parts or constructions.
Atypical Cases of Welded Structure Failures
Authors: Bernasovský Peter
Published: November 2017

First case describes hot temperature corrosion of 1.4841 heat resisting steel, which was caused by formation of the low melting nickel sulphide (LME effect).In the second case centrifugally cast tubes of Ø52.6 x 5.8 mm size made of 25/35 CrNi steel, which are exposed to high temperature and to severe reducing environment (carbon activity ac >> 1), are concerned. In such condition a graphitization may start, that results in the disintegration of its structure, which is called ,,metal dusting”.The third case is dealing with an attack of the 1.4301 steel pipe welds by microbiologically influenced corrosion. After short service time several leakages of water were revealed. It was proved, that failure was caused by microbiologically influenced corrosion of sulphate-reducing bacteria (SRB) and not by an improper welding technology.
Clinical Utility of the Sport Concussion Assessment Tool 3 (SCAT3) Tandem-Gait Test in High School Athletes
Authors: Santo Ashley , Lynall Robert C. , Guskiewicz Kevin M. , Mihalik Jason P.
Published: November 2017

Context: 

Dynamic balance during functional movement may provide important clinical information after concussion. The Sport Concussion Assessment Tool, version 3 (SCAT3), includes a timed tandem-gait test (heel-to-toe walking) administered with a pass-fail scoring system. Minimal evidence supports inclusion of the tandem-gait test in the SCAT3, especially in high school athletes.

Objective: 

To determine (1) the percentage of healthy high school athletes who passed (best trial ≤14 seconds) the tandem-gait test at baseline, (2) the association between sex and test performance (pass versus fail), and (3) the relationships among sex, age, height, and tandem-gait test score.

Design: 

Cross-sectional study.

Setting: 

High school sports medicine center.

Patients or Other Participants: 

Two hundred athletes from 4 high schools (age = 15.8 ± 1.2 years, height = 170.3 ± 10.3 cm, weight = 64.8 ± 14.5 kg).

Main Outcome Measure(s): 

Healthy participants completed 4 trials of the SCAT3 tandem-gait test and a demographic questionnaire. Outcome measures were passing rate at baseline on the tandem-gait test and tandem-gait test score (time).

Results: 

Overall, 24.5% (49/200) of participants passed the test. Sex and performance were associated (χ2 = 15.15, P < .001), with a passing rate of 38.6% (32/83) for males and 14.5% (17/117) for females. The regression model including predictor variables of sex and height, with the outcome variable of tandem-gait test score and time, was significant (R2 = 0.20, P < .01).

Conclusions: 

Our findings suggest that the tandem-gait test had a high false-positive rate in high school athletes. Given that more than 75% of healthy participants failed the tandem-gait test, the 14-second cutoff appears to have limited clinical utility in the adolescent population. Functional movement deficits after concussion need to be accounted for, but the 14-second cutoff for the SCAT3 tandem-gait test does not appear to be an ideal way to assess these deficits in high school athletes.
Prevention of Knee and Anterior Cruciate Ligament Injuries Through the Use of Neuromuscular and Proprioceptive Training: An Evidence-Based Review
Authors: Dargo Lucas , Robinson Kelsey J. , Games Kenneth E.
Published: November 2017

Reference/Citation: 

Donnell-Fink LA, Klara K, Collins JE, et al. Effectiveness of knee injury and anterior cruciate ligament tear prevention programs: a meta-analysis. PLoS One. 2015;10(12)e0144063.

Clinical Question: 

Is neuromuscular and proprioceptive training effective in preventing knee and anterior cruciate ligament (ACL) injuries?

Data Sources: 

The authors searched CINAHL, Cochrane Central Register of Controlled Trials, MEDLINE/EMBASE, PubMed, and Web of Science databases from 1996 through December 2014 and limited the results to peer-reviewed manuscripts published in English. Search terms for all databases were knee injury OR knee injuries; OR anterior cruciate ligament injury OR anterior cruciate ligament injuries; OR ACL injury OR ACL injuries; OR lower limb injury OR lower limb injuries AND prevention.

Study Selection: 

Inclusion criteria were (1) English language, (2) published from 1996 through 2014, (3) the intervention used neuromuscular or proprioceptive training to prevent knee or ACL injuries, (4) human participants, (5) the incidence of knee or ACL injury was provided.

Data Extraction: 

For the articles that met the inclusion criteria, 2 authors worked independently using the Jadad scale to extract the first author, year of publication, title, sport type, participant sex, participant age, country in which the study was conducted, number of participants in the control and intervention groups, intervention characteristics or components, and knee or ACL injury outcome.

Main Results: 

A total of 24 studies with 1093 participants were included in this review. Intervention efficacy was determined from weighted incidence rate ratios. After the intervention of neuromuscular and proprioceptive training exercises, the incidence ratio (frequency of a disease or injury occurrence in a population over a specific time frame) was calculated at 0.731 (95% confidence interval = 0.614, 0.871) for knee injury and at 0.493 (95% confidence interval = 0.285, 0.854) for ACL injury. This indicated a link between neuromuscular and proprioceptive training programs and injury reduction. No significant correlation was present between more components added to training and a greater decrease in injury to either the knee or ACL.

Conclusions: 

Neuromuscular and proprioceptive training appeared to decrease the incidence of injury to the knee and specifically the ACL. However, no evidence suggested that a specific group of exercises was better than others.
State Independent Electoral Commissions and local government elections in Nigeria
Authors: Olaniyi Johnson O.
Published: November 2017

Many state governments have not been allowing their State Independent Electoral Commissions (SIECs) to conduct elections as at when due but rather settle for ‘caretaker committees’. Where elections have been conducted, the party in control of a state apparatus has been known to have cleared the polls. The general objective of this study is to assess the impact of electoral contest at the local government level on the political development of Nigeria. Specific objectives include (1) assessing the role of the political executives of a state in the determination of representation at the local government level in Nigeria; and (2) assessing the activities of SIECs in the management of local government polls. This study adopts comparative cum case study approach to analysing local government polls in Nigeria. This is discussed on a geopolitical basis. Some of the findings of the study include: (1) local government election in Nigeria is not given premium position by many state governments in the political landscape of their state because of the fear of playing into the hands of their political rivals; and (2) SIECs are only independent in name and not in practice. The study recommends, among others, that (1) the country should adopt the arrangement in the aborted Third Republic where the country’s EMB was empowered to conduct all elections at all levels of government and (2) local government elections in Nigeria should key into the electoral process of the country in all ramifications.
Deep solidarity: Broadening the basis of transformation
Authors: Rieger Joerg , Henkel-Rieger Rosemarie
Published: November 2017

Across the globe, conditions of labour are worsening, providing both challenges and opportunities. As labour is one of the places where the intersectionality of race, ethnicity, gender, sexuality, and class is always at work, new models of resistance are created here as well. Deep solidarity describes what happens when the 99% who have to work for a living (including people who are excluded from the job market) realise what they have in common, in order to employ their differences productively in the struggle. In this article, a theologian and a labour and community organiser work together showing how the Abrahamic religious traditions and developments in the world of labour help us to shape deeper forms of solidarity.
Exploring possibilities of social entrepreneurial activities as a tool to reduce unemployment amongst churches in Tshwane central and Mamelodi East: Pretoria case study
Authors: Manyaka-Boshielo Semape J.
Published: November 2017

Unemployment is one of the major problems in South Africa. It is the concern of the government and the people at large to engage in means in order to reduce poverty. In this research, I would like to explore the possibilities of social entrepreneurial activities as a way of social and economic transformation in Tshwane. If this could be a possibility it means the church can go all out to see that the communities and members are encouraged to engage in. People will be able to improve their lives without depending on the grants from the government. Our methodology will be a literature review and intra-disciplinary approach. The method would be community mapping, World Café and focused group.
Cosmogynesis: The female hero in Tanith Lee’s The winter players
Authors: Donaldson Eileen
Published: November 2017

The mass appearance of female heroes in popular culture in recent decades may encourage the opinion that the female hero has achieved the same credibility as her male counterpart. This article demonstrates, however, that she continues to generate ambivalence and that the primary reservation of most scholars is that a female hero either cannot or should not perform the masculinity of the archetype. Scholarly arguments tend towards two positions: that a female hero is an oxymoron; or that she should be limited to battles on behalf of women in which she champions feminine characteristics and challenges the belief that femininity is not heroic. Neither of these positions take archetypal heroism into account. Advocating a return to Jungian archetypal theory, I argue that the masculinity of the archetype may be as successfully performed by a female hero as by a male hero. Once this premise is accepted, the female hero should be expected to undergo the same trials and perform the same function as a male hero, in short, she should navigate the heroic monomyth outlined by Joseph Campbell. I illustrate this point through a literary analysis of Tanith Lee’s 1976 fantasy novella The winter players.
Kan Tolkien se wêreld in Afrikaans verbeel(d) word?
Authors: Van Graan Mariëtte
Published: November 2017

No abstract available.
Facilitators and barriers to effective primary health care in Zimbabwe
Authors: Ray Sunanda C. , Masuka Nyasha
Published: November 2017

No abstract available.
We can make it happen
Authors: Kallestrup Per
Published: November 2017

No abstract available.
Non-disclosure of HIV-positive status to a partner and mother-to-child transmission of HIV: Evidence from a case–control study conducted in a rural county in Kenya
Authors: Nyandat Joram , Van Rensburg Gisela
Published: November 2017

Background: Many factors contribute to an enhanced risk of infant HIV acquisition, two of which may include failure of a mother to disclose her HIV-positive status to her partner and exclusion of male partners in preventing mother-to-child transmission of HIV (PMTCT) interventions. To justify why HIV programmes need to integrate male partner involvement and partner disclosure, we need to establish an association between the two factors and infant HIV acquisition.Objective: To determine whether failure to disclose an HIV-positive status to a male partner is associated with increased risk of infant HIV acquisition, and whether part of the association is explained by exclusion of male partner in PMTCT programmes.Methods: Using a case–control study design, we identified a total of 180 mother–baby pairs with HIV-exposed infants. Thirty-six pairs with HIV-positive babies (cases) were compared to 144 pairs with HIV-negative babies (controls) on whether the mothers had disclosed their HIV status to their partner in order to determine whether a disclosure or lack of it contributed to increased risk of mother-to-child transmission of HIV (MTCT). Each case pair was matched to four control pairs from the same facility.Results: Overall, 16.7% of mothers had not disclosed their HIV status to their partners, the proportion being significantly more among cases (52.8% vs. 7.6%, p < 0.001). Non-disclosure was significantly associated with infant HIV acquisition (aOR 9.8 (3.0–26.3); p < 0.001) and male partner involvement partially mediated the effect of non-disclosure on infant HIV acquisition (indirect coefficient = 0.17, p < 0.005).Conclusions: Failure of an HIV-positive woman to disclose her status to her male partner and exclusion of male partners in PMTCT programmes are two social factors that may curtail success of interventions towards the goal of eliminating MTCT.