bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and Characterization of SiC Nanoparticles for ATF-FCM
Authors: Chen Zhao , Liu Rong Zheng , Chang Jia Xing , Liu Ma Lin
Published: August 2018

Accident Tolerant fuel (ATF) concept was put forward after the Fukushima accident. Among different kinds of ATF, Fully Ceramic Microencapsulated Fuels (FCM) have been paid more and more attention in recent years. SiC matrix is one of the important constituent parts in FCM fuel system, which is sintered from kinds of SiC powders. In this study, SiC nanoparticles were prepared by Fluidized Bed Chemical Vapor Deposition (FB-CVD) method using Hexamethyldisilane (HMDS) as precursor, aimed at reducing the sintering temperature and pressure of FCM-SiC matrix. Experiments of different temperatures with different argon gas ratios were carried out. It was found that good crystal SiC could be obtained from 850°C to 1250°C, under pure hydrogen or H2: Ar=15:1. Different H2 carrier gas flow rate tests were also conducted. With the increase of hydrogen flow rates, the SiC was transformed from 3C-SiC to other types, such as 6H or 15R, but no significant effect was found on particle shape. Based on the characterizations of XRD, SEM and TEM, the results showed the spherical SiC nanoparticles could be obtained as well as 20 nanometers in diameter at the condition of 1150°C, H2: Ar=15:1, under different hydrogen flow rates. Different hydrogen flow rates had little influence on the particle size of SiC nanoparticles.
Research on the Performance of Carbon Fiber Reinforced Inorganic Polymer Composite
Authors: Zhang Xue Mei , Li Song , Gao Long Fei , Yu Kun , Xiao Yuan Yu , Dong Ke Xin , Lu Qiu Mian
Published: August 2018

This paper introduced a novel carbon fiber reinforced inorganic polymer non-sintering ceramic composite. It is composed of a low temperature curing material system, and can be manufactured by a traditional process for resin matrix composites. According to relevant test standards, the performances including the mechanical properties, the coefficient of linear expansion and the ablation ration were studied. The results show that the tensile strength is more than 150MPa, the bending strength is more than120MPa, the average coefficient of linear expansion is less than 0.213×10-6/°C(between room temperature and 800°C), the ablation ratio is less than 0.0715mm/s, the mass retention ratio after ablation at 1000°C for 600s is less than98%. The composite could be used for the micro ablative in large area thermal protection such as national defense, aircraft and so on.
Effect of the Synthesis Method on the Properties of Ultrafine YAG Powder
Authors: Song Jie Guang , Chen Lin , Pang Cai Liang , Zhang Jia , Wang Xian Zhong , Liu Yue , Zhang Xi Ling , Guo Song Lin , Xu Ming Han
Published: August 2018

YAG materials has a number of unique properties, the application is very extensive. In this paper, the superfine YAG powder materials were prepared by co-precipitation method and hydrothermal precipitation method. The influence of synthesis process on the morphology of the powder was investigated. The results showed that the precursor powder prepared via the co-precipitation method is mainly from amorphous to crystalline transition with the increasing calcination temperature, the precursor agglomeration is more serious, In the process of increasing the calcination temperature, the dispersibility of the roasted powder is greatly improved, which is favorable for the growth of the crystal grains, so that the particle size of the powder is gradually increased, the YAG precursor prepared by the co-precipitation method is transformed into YAG crystals, the phase transition occurs mainly between 900 and 1100°C. When the molar ratio of salt to alkali is Y3+: OH-=1: 8 via the hydrothermal reaction, the YAG particles with homogeneous morphology can be obtained. When the molar ratio of salt and alkali is increased continuously, the morphology of YAG particles is not obviously changed. The co-precipitation method is easy to control the particle size, the hydrothermal method is easy to control the particle morphology.
Study of Glass-Ceramic Coating on the SUS430 Stainless Steel Plate with High Temperature Oxidation Resistance
Authors: Huang Yong Jun , Wang Shuang Xi , Wang Wen Jun , Lan Hai Feng
Published: August 2018

Currently, the ceramic inner container draws great attention in the field of induction heating pot. Based on the traditional roll-forming process for ceramic pot, a new kind process was proposed to fabricate ceramic inner container and synchronously embed stainless steel plate by one-step high temperature sintering. The key technology for this process is to avoid the oxidation of SUS430 stainless steel plate during the high temperature sintering for a longtime by coating a glass-ceramic layer. In this research, the glass-ceramic coating with excellent high temperature oxidation resistance was optimized. The influences of ZrO2 content in the coating slurry on the high temperature oxidation resistance and thermal shock resistance of SUS430 stainless steel plate with glass-ceramic coating were studied. Meanwhile, the coatings were characterized by Scanning Electron Microscopy, X-ray Diffraction and Thermal Expansion Analysis. The experimental results showed that the glass-ceramic coating was smooth and had excellent thermal shock resistance when the addition of ZrO2 reached 15wt%. The mass gain of the SUS430 stainless steel plate with glass-ceramic coating was only 0.453% after sintering at 1300°C for 10h in air atmosphere, which was less one percent than that of SUS430 stainless steel plate under the same sintering condition.
Deposition and Electrical Resistivity of Oxygen-Deficient Tin Oxide Films Prepared by RF Magnetron Sputtering at Different Powers
Authors: Wang Qi , Peng Zhi Jian , Wang Yang , Fu Xiu Li
Published: August 2018

A series of oxygen-deficient tin oxide thin films were deposited by radio frequency magnetron sputtering a sintered tin oxide ceramic target under pure argon atmosphere at different sputtering powers (80-160 w) under the based pressure of no more than 2.0×10-4 Pa, sputtering pressure of 2.0 Pa and deposition time of 20 min. It was revealed that all the as-deposited films were oxygen-deficient tin oxide films, and the main defect in films was oxygen vacancy (VO), whose concentration gradually decreased with the increase of sputtering power. The films prepared at a power of no more than 120 w were amorphous, and as the sputtering power increased to 140 and 160 w, the deposited thin films exhibited polycrystalline characteristics with (110), (101) and (211) diffraction peaks of tin oxide. The grain size, deposition rate as well as thickness of the obtained films rose up with increasing sputtering power. In addition, as the sputtering power raised, the electrical resistivity of the films increased, due to the electron conducting mechanism controlled by VO in the samples.
Tribological Performances of CrSiN Coatings Deposited by High Power Pulse Magnetron Sputtering
Authors: Chang Wei Jie , Zhang Hao , Chen Ying Ying , Li Jun , Zhang Xue , Jiang Peng Zhan , Fan Xue Wen , Duo Shu Wang
Published: August 2018

The coatings deposited by physical vapor deposition (PVD) technique have found a wide industrial application as protective coatings for their attractive properties such as high hardness, good wear resistance and chemical stability. In order to explore the triboligical performances of CrSiN coatings, CrSiN coatings were prepared o the surface of 316 stainless steel by high power pulse magnetron sputtering (HPPMS) in this paper. Sliding wear tests of CrSiN coatings against Si3N4 ceramic balls and titanium balls have been carried out on a friction abrasion testing machine under reciprocating sliding conditions. nanoindentation and scratch tester, field emission scanning electron microscopy equipped with energy dispersive spectrometer (FESEM/EDS) and a X-ray diffractometer (XRD) was used to study the tribological behaviors of CrSiN coatings systematically. Results showed that CrSiN coatings exhibited good wear resistance, which can be attributed to the smoother and denser surface of CrSiN coatings resulted from much fewer macroparticles and pitting defects. The differences on wear debris removal behaviors and wear mechanism were caused by the different microstructure of CrSiN coatings.
Bonding Strength and Thermal Insulation Property of Thermal Barrier Coating with Nanometer Alumina Coated Zirconia
Authors: Yi Zhong Zhou , Lu Min , Shan Ke , Li Nan , Zhai Feng Rui , Xie Zhi Peng
Published: August 2018

The thermal barrier coating samples of different thickness with alumina coated zirconia and zirconia as coating materials were prepared on the surface of heat resistant alloy steel substrate after activation treatment with NiCoCrAlY as adhesive transition layer by plasma spraying method and spray gun quick spraying process. The bonding strength and thermal insulation property of two kinds of ceramic coating with the same thickness were compared by the test results of bonding strength, high temperature heat insulation and microstructure, and the relationship between the coating thickness and heat insulation effect were investigated. The results indicate that the structure and property of thermal barrier coating using nanoAl2O3coated ZrO2-Y2O3powder are superior to that using single zirconia powder. The thermal insulation property of the thermal barrier coating increased with the increasing of coating thickness, and the advantage is more obvious with temperature increasing.
Dielectric Breakdown Strength and Microwave Dielectric Properties of Alumina Ceramics with CaO-SiO2- MgO, Yb2O3 and ZrO2 Additives
Authors: Fan Gui Fen , Deng Hao Yuan , Hao Meng Meng , Wang Kai , Shi Yu Sheng , Li Chen Hui , Lu Wen Zhong
Published: August 2018

Al2O3 ceramics with CaO-SiO2-MgO (CMS), Yb2O3 and ZrO2 additives were fabricated by a conventional solid-state reaction method. The effects of ZrO2 dopant on phase compositions, microwave dielectric properties and dielectric breakdown strength of Al2O3 ceramics were studied. XRD demonstrated that CaAl2Si2O8 and Zr &Y compound phases co-existed with alumina. SEM exhibited that ZrO2 dopant could refine the grain of alumina ceramics and improve its relative density. With ZrO2 content increasing from 1wt% to 5wt% εr increased from 9.8 to 10.25, but Q×f decreased from 52823GHz to 35922GHz. The breakdown strength increased initially and reached the maximum value at ZrO2=3wt%. When ZrO2 content is 3wt%, the comprehensive performances were the best: Eb= 37.37kV/mm for 1mm samples and 17.26kV/mm for 3mm samples, Q×f = 37044 GHz, εr = 10.01, and τf = -52 ppm/°C.
Preparation and Properties of Si3N4-BaTiO3 Composite Ceramics
Authors: Zhang Ping Ping , Man Jing , Wang Hong Sheng , Wei Qi Hong , Gai Ying , Zhu Bao Xin , Li Ling
Published: August 2018

Si3N4-BaTiO3 composite ceramics, a type of high dielectric materials applied in the multifunction radome, were prepared by gas pressure-sintering method. The influences of BaTiO3 power content on the mechanical performances, dielectric properties and microstructure of Si3N4-BaTiO3 composite ceramics were investigated. The results showed that the sintering density, the elastic modulus and the flexural strength of Si3N4-BaTiO3 composite ceramics all firstly increased and then decreased along with the increase of BaTiO3 power in sample. Meanwhile, Relationship between BaTiO3 power content and dielectric properties of Si3N4-BaTiO3 composite ceramics within the frequency range of 8.2–12.4 GHz (X-band) was studied. The average of dielectric constant e of Si3N4-BaTiO3 composite ceramics increased from 7.33 to 9.98 and the average of dielectric loss tand increased from 2.8 ´ 10-3 to 0.0168 when the content of BaTiO3 power increased from 0 to 25 wt.%. The increase of the dielectric properties of Si3N4–BaTiO3 composite ceramics were attributed to the electronic and molecular polarization at interface between Si3N4 and BaTiO3, compared with the pure matrix Si3N4.
A Comparative Study of Relative Translucency of Six All-Ceramic Restorations
Authors: Zhang Mei Ling , Huang Yang , Lu Rong Jian , Deng Bin
Published: August 2018

Purpose: Compared relative translucency of IPS e.max CAD,Vita Suprinity,Lava Zirconia,Cercon Zirconia,Zenostar and upcera Zirconia, to provide a reference for the clinical aesthetic choice. Method: Relative translucency were calculated from the luminous reflectance (Y) of the specimens with a black (Yb) and a white backing (Yw) to give Yb/Yw with Minolta CR-321.One-way analysis of variance and Tukey’s multiple comparison test were used to analyze the data (P<0.05). Results: Relative translucency of control group was 0.577-0.843,while experimental group was from 0.798(IPS e.max CAD) to 0.947(upcera Zirconia),there were significantly different between the groups. The relative translucency of the six systems are as follows: IPS e.max CAD >Vita Suprinity >Lava Zirconia >Cercon Zirconia >Zenostar >upcera Zirconia. Conclusion: There were significantly different between the six groups, for patients with anterior tooth areas restoration and high aesthetic requirements, IPS e.max CAD and Vita Suprinity are recommended; For patients with poor transmittance of adjacent teeth, and the abutments are dark which need to be covered can choose Lava Zirconia and Cercon Zirconia; For low transparency like posterior areas and severe tetracycline teeth, upcera Zirconia and Zenostar ceramic blocks may be considered.
Electronic Structure and Transport Properties of La2Zr2O7 Pyrochlore from First Principles
Authors: Li Zheng , Pan Wei
Published: August 2018

The first principle calculation as well as the Boltzmann transport calculation have been employed to study the high temperature electronic transport properties of pyrochlore La2Zr2O7. Combing constant scattering time approximation and experiment data, the electronic thermal conductivity and electron concentration are calculated as a function of temperature. The electronic thermal conductivity is 2.6×10-4 W/(m.s) at 1270K and 7.2×10-3 W/(m.s) at 1770K. The electron concentration increase rapidly with when the temperature is above 1600K.
On the Sol-Gel Synthesis and Structure, Electronic and Ionic Conductivities and Impedance Behavior of Y, Fe Co-Doped SrTiO3 Mixed Conductor
Authors: Shan Ke , Zhai Feng Rui , Li Nan , Yi Zhong Zhou
Published: August 2018

A single phase perovskite, YxSr1−xTi0.6Fe0.4O3-δ(x=0.06-0.09), was fabricated at 1350°C in air by sol-gel method. The effects of Y-and Fe-doping into SrTiO3on phase structure, electrical conductivity, ionic conductivity and its impedance behavior were investigated. The optimized Y0.07Sr0.93Fe0.4Ti0.6O3-δsample exhibits an electrical conductivity of 0.135 S·cm-1at 800 °C. Y-doping decreases the migration energy for oxygen ions, leading to a significant increase in ionic conductivity. The ionic conductivity of Y0.09Sr0.91Ti0.6Fe0.4O3-δsample varies from 0.0052 S· cm-1at 600°C to 0.02 S·cm-1at 800°C. Impedance characteristics over a wide frequency range of 0.01Hz-100 KHz reveal that the resistance of ionic conduction is predominantly influenced by grain boundary, the relaxation time of which decreases with increase of Y-doping amount.
Effect of Ammonia on CeO2 Microspheres Prepared by Internal Gelation Process
Authors: Ding Xue Qiang , Ma Jing Tao , Zhao Xing Yu , Hao Shao Chang , Deng Chang Sheng , Li Guan Xing
Published: August 2018

The internal gelation process was used to prepare cerium dioxide microspheres. The effect of ammonia on the stability of the precursor solutions was investigated with the NH3∙H2O/Ce (NH4)2(NO3)6 molar ratio from 0 to 1.25. The surface morphology and microstructure of the sintered CeO2 microspheres were analyzed. With the increase of NH3∙H2O/Ce (NH4)2(NO3)6 molar ratio, the solutions became more unstable, which indicated that their gelation was initiated. When the NH3∙H2O/Ce (NH4)2(NO3)6 ratio varied from 0 to 0.75, the surface of the microspheres became rougher and grain size became larger. Further increase in the NH3∙H2O/Ce (NH4)2(NO3)6 ratios to 1 and 1.25 led to CeO2 microspheres with smooth surface and compact structure.
Drying Stability and Critical Height of Repeating Line/Space Structures
Authors: Bassett Derek W.
Published: August 2018

Analytical prediction of capillary pattern collapse is done by balancing the capillary forcesdue to the curved liquid interface with the elastic forces due to the bending of the structure. This paperintroduces a more realistic model where there is an array of repeating lines and spaces, and compares itto the traditional model of two single lines with liquid-filled space in between. This paper also includesthe influence of a non-vertical sidewall angle, and its effect on the overall elastic force. Results showthat the repeating structures and non-vertical sidewall angles both predict a higher critical height beforecollapse occurs compared to the traditional model.
Cleaning of High Aspect Ratio STI Structures for Advanced Logic Devices by Implementation of a Surface Modification Drying Technique
Authors: Sebaai Farid , Vereecke Guy , Xu Xiu Mei , Baudot Sylvain , Amemiya Fumihiro , Komori Kana , Holsteyns Frank
Published: August 2018

The continuous down scaling of the dimensions for the logic devices has imposed to carefully track the pattern collapse issue when cleaning after FIN etch. Showing the limitations of the hot IPA drying technique toward scaled FIN dimensions, a cleaning using a surface modification drying technique has been proposed and successfully implemented. It is also discussed the use of some post treatment solutions to remove the grafted layer used to modify the FIN surface while preserving the integrity of the FIN structures.
Pattern Collapse-Free Drying with Sacrificial Gap Fill Polymers
Authors: Varaprasad Desaraju , Xie Songyuan , Kennedy Evelyn , Gebrebrhan Amanuel , Huang Hongmin , Kennedy Joseph
Published: August 2018

This work discusses pattern collapse-free drying by application of a sacrificial polymer during the semiconductor wafer cleaning process. The sacrificial polymer is dispensed onto the wafer, displacing the rinse liquid and subsequently dried to form a solid polymer fill within the patterned structure, providing both mechanical support and a means for dry polymer removal by either plasma or thermal exposure. Polymer film thickness, gap fill capability and removal rate are explored for plasma ashable and thermally removable polymer families.
Process Parameter Control for BEOL TiN Hard Mask Etch-Back
Authors: Okorn-Schmidt Harald , Engesser Philipp , Linder Manuel , Hofer-Moser Jörg
Published: August 2018

In this paper we demonstrate an effective process control mechanism to significantly improve on the process performance of a BEOL post-etch cleaning process with an integrated partial or complete removal of the TiN HM (hard mask) layer by so called formulated chemistries on a single wafer processing tool. The novel process control mechanism enables a 50% reduction in chemical consumption while achieving an at least equivalent TiN etch uniformity.
BEOL Post-Etch Clean Robustness Improvement with Ultra-Diluted Hf for 28nm Node
Authors: Broussous Lucile , Fabre Remy , Massin Thomas , Ishikawa Hiwadezu , Buisine Fabrice , Lamaury Alain
Published: August 2018

For 28 nm and beyond, severe specifications in terms of dimensions and materials integrity still drive further cleaning process improvements. As the global “HF budget” drastically decreases with interconnections dimensions, HF solution dilution and process time both decreased stepwise. However, very short recipes with process time shorter than 15s start to suffer from lack of robustness, in particular for the monitoring of inline parameters such as flow-rates and temperature. In this paper, we highlighted that a first matching of silicon oxide consumption was usefull to select temperature and concentration range for the diluted HF solution. High dilution ratio, and “room temperature” (20 °C) were then selected. Variations in cleaning efficiency were analyzed as regard with electrical defects density at three metals levels, then the use of 0.025 %wt. HF, 20 °C, 40 s. was pointed out as the more promising solution for process of record replacement. Process robustness, i.e. inline monitoring data collection and uniformity on wafer should thus be improved thanks to this longer process time and a lower process temperature.
Wet-Chemical Etching of Ruthenium in Acidic Ce4+ Solution
Authors: Philipsen Harold , Teck Sander , Mouwen Nils , Monnens Wouter , Le Quoc Toan
Published: August 2018

The wet-chemical etching of ruthenium in acidic solutions of cerium (IV) has been investigated using electrochemical methods. Etch rates were determined using Rutherford backscattering spectroscopy (RBS) and post-etching surface roughness was investigated using atomic force microscopy (AFM). Low-k material is compatible with the etchant, however, residues were formed.
Wet Processing in State-of-the-Art Cu(In,Ga)(S,Se)2 Thin Film Solar Cells
Authors: Buldu Dilara Gokcen , de Wild Jessica , Kohl Thierry , Suresh Sunil , Birant Gizem , Brammertz Guy , Meuris Marc , Poortmans Jef , Vermang Bart
Published: August 2018

Interface quality plays a key role in solar cell applications. Interface recombination at the front and rear surfaces, which determine this quality, have significant effects on open circuit voltage and fill factor values. In this work, several surface treatments were applied on Cu(In,Ga)Se2 (CIGS) surfaces to improve the interface quality. Besides, the passivation layer implementation was investigated to reduce interface recombination between the buffer and absorber layers.
Yield Enhancement due to Addition of Bevel Cleans at Middle of Line(MOL) Zone
Authors: Tharchin Tsultrim , Balu Elango , Singh Sherjang
Published: August 2018

As the technology nodes become smaller and smaller the circuit dies get closer and closer to the edge of the wafer. Defects and issues on the bevel are seen to cause issues such as flaking and blocked plating on the dies at the edge of the wafer. This drastically increases the need for a clean wafer edge as the issues directly translate to yield loss at the end of the line. The wafer edge and backside are shown to have a significant impact on yield as well as process variation [1]. Introducing a dilute HF and SC1 bevel clean at the MOL layer resolves flaking and defect issues found on the bevel. Dispensing it on the backside of the wafer and ensuring that the chemistry is rolled over to the bevel results in the backside of the wafer becoming cleaner and helps resolve overlay issues. All the above stated effects are seen to result in an overall edge gain in edge yield.
Removal of CrN Contamination from EUV Mask Backside Using Dry Cleaning
Authors: Kim Hyun Tae , Yerriboina Nagendra Prasad , Song Hee Jin , Park Jin Goo
Published: August 2018

For EUV lithography, a reflective mask is essential because of use of the strong energy, wavelength of 13.5 nm. The EUV mask consists of multi-layered, multi-material structure and is susceptible to various contaminants. Since EUV lithography process should be used in a high vacuum environment, an electrostatic chuck (ESC) is used to fix or hold the EUV mask using electrostatic force. In general, in order to use ESC chuck, it needs a thin conductive layer (CrN layer) on the backside. However, the contact points of the electrostatic pin chuck can make exfoliation of conductive CrN layer producing CrN particles. If these particles are present on the backside of the mask, CD or DOF may be affected during EUV exposure. The 1 μm particle can leads to a gap radius of 42mm [4]. Moreover, these backside particles may travel to the front side. Therefore, backside cleaning should be performed to remove particles from the mask backside surface.
Damage-Free Cleaning of Advanced Structure Using Timely Energized Bubble Oscillation Megasonic Technology
Authors: Wang David H. , Chen Fu Ping , Zhang Xiao Yan , Wang Xi , Chen Fu Fa , Henry Sally Ann , Chae Kwang Kee , Chu Zhen Ming , Liu Feng , Chen Yang , Lei Hai Bo , Ni Li Hua , Zhang Yu , Zhu Ye Fang , Li Fang , Zhang Tao
Published: August 2018

The use of highly corrosive chemicals to remove nano-particles on the surface of the wafer, results in substrate losses. This has resulted in the use of megasonics which provides acoustic cavitation to remove small particles. The megasonic wave does generate bubble cavitation which applies mechanical force to wafer structure, the violent cavitation such as transit cavitation or micro jet will damage the patterned structures [1,2]. A new megasonic technology is proposed in this paper, this technology provides stable control of bubble cavitation, without pattern damage at the different modes. The technology shows better particle performance when compared with the industry standard two-fluid nozzle cleaning technology. This Timely Energized Bubble Oscillation mode provides stable cavitation with a wide power window. It is unlike conventional megasonic which creates transit cavitation and damage when the bubble implodes. This new megasonic technology can be used to clean “sensitive” structures at 28nm and below without any pattern damage.
The Gorean Community in Second Life: Rules of Sexual Inspired Role-Play
Authors: Sixma Tjarda
Published: August 2018

Gor is one of the most successful role-play themes in the Virtual World of Second Life (SL). In this theme, player-characters act out a barbaric world of sexual slavery that is based on the novels of John Norman. Norman’s narrative comes alive in privately owned 3D simulations (SIMs) that depict settlements in Roman, Viking, or tribal style. This paper gives insight into the construction of Gorean role-play, and positions it within the discourse on role-play in Virtual Worlds. The role-play was studied by undertaking an ethnographic participant-observation. Moreover, the rules of the city of Veroda (a pseudonym) are analysed in detail. The analysis shows that Veroda’s rules aim at immersion in the role-play experience and are concerned with the power structure of the SIM, as well as with the personal power relationships of its members. In conclusion, Gorean SIM communities are closed or semi-closed social groups that act as real communities “living” in a particular shared online place. Whereas within gaming worlds the play occurs under the rules of game-design, Gorean role-play groups in Second Life construct their own social rules and play. In doing so, they create and maintain a vibrant community life.
Virtual Worlds, Collective Responses and Responsibilities in Health
Authors: Kashani Rashid M , Roberts Anne , Jones Ray , Kamel Boulos Maged N.
Published: August 2018

Virtual worlds are an exciting area offering opportunities in clinical teaching and interventions. Clinicians and academics alike may approach these emerging opportunities with enthusiasm or scepticism. Attitudes towards applying virtual worlds in clinical practice may arise from a number of sources, facilitating a more or less positive view towards this media. Virtual worlds have the potential to provide a considerable amount of control to the end users, in this case, the client’s, hands. The argument put forth is that we should collectively acknowledge changes in information technology and the power this gives the health care user, but we also have a collective responsibility in ensuring virtual worlds are adapted, tested and studied with sufficient rigour to benefit health care consumers and population needs. Occupational therapists specifically may be in a unique position to adopt the use of virtual worlds in clinical practice.
The Growth and Direction of Healthcare Support Groups in Virtual Worlds
Authors: Norris John Robert
Published: August 2018

What is the growth and direction of healthcare support groups grow in virtual worlds? Data was collected on over 300 groups from virtual worlds, Second Life, IMVU, There, and Kaneva. A collection of non-virtual world support groups was added. Similar categories of groups were found to be generally popular across worlds. The percentage of groups in categories of healthcare issues was also generally analogous between worlds. The long tail effect was shown- only a few groups had high populations. Group creation rate displayed generally similar growth between worlds. The worlds' demographics and features were suggested to account for differences. Limited data availability and vague definitions of groups and categories hampered analysis.
Supporting Soundscape Design in Virtual Environments with Content-based Audio Retrieval
Authors: Janer Jordi
Published: August 2018

The computer-assisted design of soundscapes for virtual environments has received far less attention than the creation of graphical content. In this “think piece” we briefly introduce the principal characteristics of a framework under development that aims towards the creation of an automatic sonification of virtual worlds. As a starting point, the proposed system is based on an on-line collaborative sound repository that, together with content-based audio retrieval tools, assists the search of sounds to be associated with 3D models or scenes.
On the creation of standards for interaction between real robots and virtual worlds.
Authors: Juarez Alex , Bartneck Christoph , Feijs Lou
Published: August 2018

Research on virtual worlds and environments has increased tremendously in the last decade, giving birth to a variety of applications spanning over several areas such as virtual reality, human-computer interaction, psychology and sociology, among others. In this paper we elaborate on one issue affecting the areas of virtual worlds and robotics: the lack of standard mechanism for communication and interaction between virtual worlds and real robots.
Virtual Worlds, Collaboratively Built
Authors: Rosendale Philip
Published: August 2018

Even before they really existed, I deeply believed that virtual worlds would have a profound impact on the real world, ultimately affecting the lives of people worldwide, in much the same way that the World Wide Web itself has brought about a dramatic transformation in how we communicate. Now that Second Life—and more broadly, virtual worlds—have become at least "worthy of criticism,” I am all the more convinced that this will prove to be true. We will soon see virtual worlds expand from millions of active users to billions.
Real Standards for Virtual Worlds – Why and How?
Authors: Jakobs Kai
Published: August 2018

The paper provides guidelines for potential those who would like to pro-actively participate in ICT standards setting. Some of the more tricky and confusing terms are discussed, as are the characteristics of today’s ICT standardisation environment. Finally, the paper gives more concrete advice how to identify the most suitable standards setting body for a given technology to be standardised.
Second Life Unplugged: A Design for Fostering At-risk Students' STEM Agency
Authors: Harrell Sneha Veeragoudar , Abrahamson Dor
Published: August 2018

At an alternative high school serving predominantly at-risk underrepresented students evicted from mainstream education, we designed and implemented Fractal Village, a critical-constructionist computational and mathematical pedagogy learning environment. Fractal Village, instantiated in the virtual world "Second Life," constituted an empirical environment to research our emergent model of mathematical/computational agency (m/c) as well as an interventionaiming to foster such agency. Key research objectives were to: (1) study relations amongst cognitive, affective, material, technological, and social factors that would contribute to individual development of m/c agency; and (2) delineate design principles for fostering m/c agency. The student cohort engaged collaboratively in virtual world imaginative construction activities each manifesting generative themes (Freire, 1968), to which the designers-as-teachers tailored mathematical and computer-science concepts, such that students appropriated the STEM content apropos of tackling their own emergent construction problems. We argue that to build agency, students must develop both skills and dispositions—a spiraling inter-constructive growth—and articulate a developing methodology for fostering agency development. We conclude that wecan, and must, engage at-risk youth by helping them to build STEM-oriented identities, engaging their a priori m/c agency, and customizing skills and dispositions-related classroom discursive supports.
Patterns of pituitary dysfunction three months or more after traumatic brain injury
Authors: Yaseen Nassar Taha , Al-Khaqani Fateh , Mansour Abbas Ali
Published: August 2018

Purpose: Chronic posttraumatic brain injury (TBI) pituitary dysfunction is not a newly discovered subject, it has been reported more frequently, probably due to increasing chances of exposure to its causes, mainly the road traffic accidents, sport-related injuries, falls, and injuries during wars. This study aims to estimate the frequency of pituitary dysfunction 3 months or more after head trauma and the patterns of hormonal deficiencies. Methods: A cross-sectional study was conducted between January 2016 and August 2017. Participants were patients having a history of moderate-to-severe TBI at least 3 months before enrolment. Pituitary function test was done for all patients to determine the frequency of pituitary dysfunction, the number of axes deficiencies, and which hormone is mostly affected. Statistical Package for the Social Sciences (SPSS) version 23.0 was used for univariate analysis, P < 0.05 was considered statistically significant. Results: Out of the 28 patients involved in this study, 17 (61%) had pituitary dysfunction, while 11 (39%) had not. Single hormonal defect was the most prevalent abnormality in 12 (43%), and the most affected hormone was the growth hormone (GH) in 14 patients (50%), followed by gonadal axis, thyroid stimulating hormone, and finally adrenocorticotropic hormone (ACTH), 6 (21%), 3 (11%), and 1 (4%), respectively. Conclusion: TBI pituitary dysfunction is more prevalent than was predicted in the population studied, single hormonal defect was found to be the most prevalent abnormality, being the GH is the most affected axis, and the ACTH seems to be the least.
Ciliated Foregut Cyst of the Pancreas Presenting as a Mucinous Cystic Neoplasm
Authors: Huq Nadia , Papenfuss Wesley , Guda Nalini M.
Published: August 2018

A 53‑year‑old underwent an abdominal computed tomography for hematuria that incidentally discovered a cystic lesion of the pancreas. Endoscopic ultrasound revealed a structure with debris and septations; fine‑needle aspiration with negative cytology but elevated tumor marker suggested a mucinous cystic neoplasm or an intraductal papillary mucinous neoplasm. Laparoscopic excision confirmed a walled‑off cyst detachable from the posterior aspect of the pancreas consistent with a ciliated foregut cyst. There are limited data on ciliated foregut cysts of the pancreas, and the current report highlights the diagnostic dilemma and a review of the current literature.
Migration of Pigtail Biliary Stent through Surface of the Left Lobe of Liver
Authors: Shah Bhavik Bharat , Goenka Usha , Banerjee Debashish , Rai Vijay , Goenka Mahesh Kumar
Published: August 2018

We report a rare case of a patient of choledocholithiasis who underwent CBD stone removal with pigtail biliary stenting four year back, presenting with proximal migration of stent piercing the left lobe of liver. The stent was removed at laparotomy, by doing hepatotomy. We discuss this unreported case of proximal migration of pigtail biliary stent through surface of left lobe of liver.
Palliation of Obstructive Jaundice: Endoscopic Ultrasound‑guided Choledochoduodenostomy in the Presence of Bleeding Duodenal Infiltration Due to Metastatic Urinary Bladder Cancer
Authors: Rana Surinder Singh , Sharma Ravi , Gupta Rajesh , Ahmed Sobur Uddin
Published: August 2018

Obstructive jaundice is a common manifestation of malignancies involving pancreaticobiliary area of the gastrointestinal tract. The palliation of obstructive jaundice involves bypassing the obstruction by an endoprosthesis using either endoscopic retrograde cholangiopancreatography (ERCP) or percutaneous transhepatic biliary drainage route. Endoscopic ultrasound‑guided choledochoduodenostomy (ECD) is a challenging alternative for obstructive jaundice due to distal bile duct obstruction in patients who have failed ERCP. In this report, we describe a challenging case of disseminated urinary bladder cancer that presented with extensive duodenal as well as periduodenal infiltration leading on to gastrointestinal bleed and severe pruritus along with obstructive jaundice and was successfully managed with initial argon plasma coagulation of bleeding duodenal lesions followed by ECD.
Короткие единичные тесты для схем при произвольных константных неисправностях на выходах элементов
Authors: Popkov Kirill Andreevich
Published: August 2018

Доказаны следующие факты:
1) любую неконстантную булеву функцию можно реализовать неизбыточной схемой из функциональных элементов в базисе $\{x&y,$ $\overline x,x\oplus y\oplus z\}$, допускающей единичный проверяющий тест длины не более 2 относительно произвольных константных неисправностей на выходах элементов,
2) существует такая булева функция $\psi$ от шести переменных, что любую неконстантную булеву функцию можно реализовать неизбыточной схемой из функциональных элементов в базисе $\{\psi\}$, допускающей единичный диагностический тест длины не более 3 относительно произвольных константных неисправностей на выходах элементов.
Investing In the Mekong River Delta of Vietnam – The Opportunity for Small and Medium Enterprises of Korea
Authors: Hanh Doan Thi My , Tien Ma Bich , Liem Dang Thanh
Published: August 2018

This article provides a direction for furfure research in small and medium enterprises invest in foreigner countries; specially in Vietnam market. The major projects that Korea Enterprises invested covered mostly in the Northern of Vietnam provinces such as Bac Ninh, Ha Noi, Hai Phong, Thai Nguyen. Meanwhile, in southern Vietnam, the Mekong River Delta region with many projects calling for investment in agriculture and tourism has not attracted much attention from Korean investors. The article using the method of descriptive statistics to overview the project investment in agriculture and tourism of the Mekong Delta of Vietnam and points out the advantages of Korean small and medium enterprises (SMEs) in these two sectors. The results of study showed that Mekong River Delta has incentive policies for investment. Besides, with the general policy of Vietnamese government for agriculture and tourism projects, they had incentive policies for foreigner invest in these fields. Moreover, Korea has many small and medium enterprises (SMEs) as well as investing experience in Vietnam. This articles strongly encourages the research of the opportunity for foreigner SMEs invest in tourism and agriculture in other countries, especially emerging market as Vietnam.
Jeca Tatu, um ilustre opilado: o movimento sanitarista e o combate à anciolostomíase na obra de Monteiro Lobato (Brasil, décadas de 1910-1920)
Authors: Korndörfer Ana Paula
Published: August 2018

Ao longo da década de 1910, iniciou-se uma campanha pela reforma da saúde e pelo saneamento rural no Brasil. Uma das principais bandeiras dessa campanha era o combate às endemias rurais, como a ancilostomíase. Em um contexto de estreita relação entre o campo literário e a área médica, nossa proposta, neste artigo, é recuperar parte da discussão que aborda os reflexos dos argumentos e das propostas dos defensores do movimento sanitarista sobre a obra do escritor Monteiro Lobato, enfocando, no entanto, o combate à ancilostomíase, a partir de uma breve discussão da trajetória de Jeca Tatu, um de seus mais conhecidos personagens.
Assessoria jurídica universitária popular e a formação do bacharel em Direito
Authors: Bezerra Oliveira Damião , Gomes Raphael Carmesin
Published: August 2018

O presente artigo visa a descrever as contribuições que o programa de extensão universitária Núcleo de Assessoria Jurídica Universitária Popular Aldeia Kayapó (Najupak) deu durante sua existência, para a formação do bacharel em Direito da Universidade Federal do Pará (UFPA). Para esse fim, além do referencial teórico que embasa as experiências e práticas da assessoria jurídica universitária popular (Ajup), exploram-se os discursos de bacharéis em Direito que, em algum momento de seu percurso formativo, participaram deste programa de extensão em seus 10 anos de existência (2004-2014). Nesse sentido, transcrevem-se as narrativas dos bacharéis, colhidas em entrevistas semiestruturadas, realizadas para a consecução da dissertação de mestrado apresentada ao Programa de Pós-Graduação em Educação da UFPA. Conclui-se que o Najupak foi essencial na promoção de uma formação paralela dos bacharéis em Direito, proporcionando a eles experiências pedagógicas diferenciadas do currículo oficial, por meio do estímulo às reflexões críticas sobre a própria formação jurídica.
Análisis del marco jurídico regulatorio y del procedimiento de inversión en el sub sector eléctrico de las energías renovables en Nicaragua
Authors: Jiménez Pichardo Cinthya Lucia
Published: August 2018

Nicaragua es un país que se caracteriza por tener recursos energéticos diversos y en abundancia, estos recursos naturales, gozan de un alto potencial para la explotación de energía renovable, ya sea hidroeléctrica, geotérmica, eólica, solar o biomasa. Por lo tanto, el análisis del marco jurídico regulatorio y del procedimiento de inversión referente a las energías renovables, se muestra como un estudio necesario ante las realidades económica, social y jurídica por las que en la actualidad atraviesa nuestro país. La ventajosa posición geográfica de Nicaragua, los abundantes recursos naturales que posee y la exuberante necesidad de inversión en este sector, hacen del presente estudio una interesante reflexión y aporte, al menos desde el punto de vista teórico – jurídico. El desarrollo e incentivo por parte del Estado para la generación de energía a través de fuentes renovables, no solamente es idóneo sino necesario para el desarrollo del sub sector eléctrico nacional, siendo que proyectos de esta envergadura son el ideal colaborador para los proyectos de expansión energética y de electrificación rural que el Gobierno de Nicaragua ha impulsado hace varios años; con la publicación de la Ley No. 532, Ley para la promoción de generación eléctrica con fuentes renovables, se impulsó la generación limpia en el país, otorgando a los inversionistas una serie de beneficios fiscales, pero la misma no se muestra suficiente. El presente artículo muestra un análisis del marco jurídico regulatorio en el sub sector eléctrico de las energías renovables identificando oportunidades de mejora que coadyuvarían al desarrollo del sector.
Time to improvement in semen parameters after microsurgical varicocelectomy in men with severe oligospermia
Authors: Masterson Thomas A. , Greer Aubrey B. , Ramasamy Ranjith
Published: August 2018

Introduction: We aimed to determine the time and predictive factors of semen quality improvement in men with severe oligospermia after microsurgical varicocelectomy.
Methods: Men with total motile sperm count (TMSC) <5 million on two semen analyses were identified from May 2015 to August 2017. Postoperative semen analysis was collected at 3–6 months and >6 months. We evaluated preoperative factors for successful semen quality upgrading based on assisted reproductive technology (ART) eligibility: in vitro fertilization [IVF] (<5 million), intrauterine insemination (IUI) (5–9 million), and natural pregnancy (>9 million). We compared men with TMSC <5 million to those with TMSC 5–9 million. Data are reported as means and standard error of the mean (SEM). Pregnancy data was collected by phone interview at >6 months postoperatively.
Results: A total of 33 men were included. TMSC improved from 1.5±0.2 to 7.3±1.8 million at 3–6 months (p<0.05) and 12.2±3.6 million at >6 months (p<0.05). There was no statistical difference in TMSC between 3–6 months and >6 months. Sixteen (48.5%) men upgraded semen quality into the range of natural pregnancy. Preoperative TMSC from 2–5 million was predictive of upgrading semen quality. Twenty-four couples were contacted by phone; 20 were attempting pregnancy in the postoperative period and five (25%) of them had achieved natural pregnancy.
Conclusions: Men with TMSC <5 million can expect the largest improvement in TMSC from 3–6 months postoperatively with minimal improvement thereafter. Preoperative TMSC >2 million was most predictive of semen quality upgrading.
Contribution to the knowledge of mycobiota of the Western Sudety Mountains and Western Sudety Foothills (SW Poland). Part 1
Authors: Gierczyk Błażej , Soboń Ryszard , Pachlewski Tomasz , Ślusarczyk Tomasz
Published: August 2018

The paper presents the results of several years of mycological studies carried out in Poland, in the Western Sudety Mountains (the Karkonosze, Kaczawskie, Izera, and Rudawy Janowickie mountains), Western Sudety Foothills (the Izerskie and Kaczawskie Foothills), and adjacent regions, such as the Jelenia Góra Valley, Lubawska Gate, and Sudety Foreland (the Niemczańsko-Strzelińskie Hills). During the study, the presence of 985 fungal taxa (species, varieties, and forms) was recorded; of these, 66 had hitherto not been observed in Poland.
Proteína G - mecanismos moleculares de comunicação celular
Authors: Silva Diógenes O. , Ahmad Najlah R. M. , Soares Iberê C. , Kraemer Cristiane K. , Buss Sandro O. , Mello Carlos Fernando de
Published: August 2018

In the present paper the authors commnent on the physiological role of G proteins in transmission signalling process and some alterations of this system. The review is directed to beginners and emphasize a visual approach to the theme.
Preservice Teachers' Mathematical Visual Implementation for Emergent Bilinguals
Authors: I Ji-Yeong , Stanford Jasmine
Published: August 2018

Using visuals is a well-known strategy to teach emergent bilinguals (EBs). This study examined how preservice teachers (PSTs) implemented visuals to help EBs understand mathematical problems and how an innovative intervention cultivated PSTs' capability of using visuals for EBs. Four middle school mathematics PSTs were engaged in a _ eld experience with EBs to work on mathematical problems; during the _ eld experience, the PSTs received interventions. In one intervention session, the PSTs were asked to make sense of a word problem written in an unknown language with different visuals. After this intervention, they changed their use of visuals when modifying tasks for EBs. The results suggest that immersive experiences where PSTs can experience learning from the perspective of EBs helps PSTs implement mathematically meaningful visuals in a way that makes mathematical problems accessible to EBs.
Using Mancala in the Mathematics Classroom
Authors: de Voogt Alex , Rougetet Lisa , Epstein Nathan
Published: August 2018

Adapting the centuries-old game of mancala provides basic exercises on mathematical modeling.
MTMS Favorites: “Never Say Anything a Kid Can Say!”
Authors: Edwards Clayton
Published: August 2018

Members of the Editorial Panel are spotlighting articles from the twenty-three-year history of MTMS. In this offering, the takeaways include student thinking and student voicing.
Saving Piglets
Authors: Poulsen Aubrey
Published: August 2018

Students are given a real-life agricultural problem describing baby pig survival.
Insulating and conducting heat energy using STEM
Authors: Houghton Jenni L.
Published: August 2018

Contributors to the iSTEM department share ideas and activities that stimulate student interest in the integrated fields of science, technology, engineering, and mathematics (STEM) in K–grade 6 classrooms. This article is a STEM lesson on insulators and conductors for heat energy.