bluuebunny/crossref_metadata_2025 huggingface dataset:
The importance of atlantoaxial fixation after odontoidectomy
Authors: Chang Peng-Yuan , Yen Yu-Shu , Wu Jau-Ching , Chang Hsuan-Kan , Fay Li-Yu , Tu Tsung-Hsi , Wu Ching-Lan , Huang Wen-Cheng , Cheng Henrich
Published: October 2015

OBJECT

Although anterior odontoidectomy has been widely accepted as a procedure for decompression of the craniovertebral junction (CVJ), postoperative biomechanical instability has not been well addressed. There is a paucity of data on the necessity for and choice of fixation.

METHODS

The authors conducted a retrospective review of consecutively treated patients with basilar invagination who underwent anterior odontoidectomy and various types of posterior fixation. Posterior fixation included 1 of 3 kinds of constructs: occipitocervical (OC) fusion with atlantoaxial (AA) fixation, OC fusion without AA fixation, or AA-only (without OC) fixation. On the basis of the use or nonuse of AA fixation, these patients were assigned to either the AA group, in which the posterior fixation surgery involved both the atlas and axis simultaneously, regardless of whether the patient underwent OC fusion, or the non-AA group, in which the OC fusion construct spared the atlas, axis, or both. Clinical outcomes and neurological function were compared. Radiological results at each time point (i.e., before and after odontoidectomy and after fixation) were assessed by calculating the triangular area causing ventral indentation of the brainstem in the CVJ.

RESULTS

Data obtained in 14 consecutively treated patients with basilar invagination were analyzed in this series; the mean follow-up time was 5.75 years. The mean age was 53.58 years; there were 7 males and 7 females. The AA and non-AA groups consisted of 7 patients each. The demographic data of both groups were similar. Overall, there was significant improvement in neurological function after the operation (p = 0.03), and there were no differences in the postoperative Nurick grades between the 2 groups (p = 1.00). According to radiological measurements, significant decompression of the ventral brainstem was achieved stepwise in both groups by anterior odontoidectomy and posterior fixation; the mean ventral triangular area improved from 3.00 ± 0.86 cm2 to 2.08 ± 0.51 cm2 to 1.68 ± 0.59 cm2 (before and after odontoidectomy and after fixation, respectively; p < 0.05). The decompression gained by odontoidectomy (i.e., reduction of the ventral triangular area) was similar in the AA and non-AA groups (0.66 ± 0.42 cm2 vs 1.17 ± 1.42 cm2, respectively; p = 0.38). However, the decompression achieved by posterior fixation was significantly greater in the AA group than in the non-AA group (0.64 ± 0.39 cm2 vs 0.17 ± 0.16 cm2, respectively; p = 0.01).

CONCLUSIONS

Anterior odontoidectomy alone provides significant decompression at the CVJ. Adjuvant posterior fixation further enhances the extent of decompression after the odontoidectomy. Moreover, posterior fixation that involves AA fixation yields significantly more decompression of the ventral brainstem than OC fusion that spares AA fixation.
Autologous bone graft versus PEKK cage for vertebral replacement after 1- or 2-level anterior median corpectomy
Authors: Koehler Stefan , Raslan Furat , Stetter Christian , Rueckriegel Stefan Mark , Ernestus Ralf-Ingo , Westermaier Thomas
Published: October 2015

OBJECT

Anterior cervical corpectomy with fusion has become the most widely used procedure for the treatment of multilevel cervical stenosis. Although an autologous bone graft is the gold standard for vertebral replacement after corpectomy, industrial implants have become popular because they result in no donor-site morbidity. In this study, the authors compared clinical and radiological results of autologous iliac grafts versus those of bone-filled polyetherketoneketone (PEKK) cage implants.

METHODS

The clinical and radiological data of 46 patients with degenerative multilevel cervical stenosis and who underwent 1- or 2-level anterior median corpectomy between 2004 and 2012 were analyzed. The patients in Group 1 were treated with vertebral replacement with an autologous iliac graft, and those in Group 2 were treated with a PEKK cage implant. Each patient also underwent osteosynthesis with an anterior plate-screw system. Visual analog scale (VAS) and European Myelopathy Scale scores, loss of height and regional cervical lordosis angle, and complication rates of the 2 groups were compared.

RESULTS

The mean follow-up time was 20 months. In both groups, the VAS and European Myelopathy Scale scores improved significantly. The loss of height was 3.7% in patients with iliac grafts and 5.3% in patients with PEKK implants. The rates of osseous fusion were similar in Groups 1 and 2 (94.7% and 91.3%, respectively). At the end of the follow-up period, none of the patients complained about donor-site pain. One patient in Group 1 suffered a fracture of the iliac bone that required osteosynthesis. Four patients in Group 2 had to receive revision surgery for cage and/or plate-screw dislocation and new neurological deficit or intractable pain.

CONCLUSIONS

Preoperative pain and radicularand myelopathic symptoms improve after decompression irrespective of the material used for vertebral replacement. The use of PEKK cages for vertebral replacement seems to result in a higher risk of implant-related complications. A prospective randomized study is necessary to supply evidence for the use of autografts and artificial implants after anterior cervical corpectomy with fusion.
The Role of Religion in the Neolithic of the Middle East and Anatolia with Particular Reference to Çatalhöyük
Authors: Hodder Ian
Published: October 2015

This paper considers some of the arguments in Cauvin’s book Naissance des divinités, Naissance de l’agriculture in the light of new research conducted at Çatalhöyük regarding the role of religion in the Neolithic. This research has brought together anthropologists, philosophers and religious scholars to work with archaeologists in answering four questions all of which have been inspired by Cauvin’s work. The questions deal with (1) the definition and archaeological recognition of religion, (2) the relationships between religion and social and economic change, (3) the role of new forms of human agency in the domestication of animals, and (4) the part played by symbolism of violence and death in the formation of settled village life. The evidence and discussion of Çatalhöyük lead to new insights in all these domains.
Isolation and characterization of microsatellite loci in Rehmannia glutinosa (Scrophulariaceae), a medicinal herb
Authors: Jiao Zhenbin , Cheng Yueqin , Wang Hongwei , Lei Caiyan , Wang G. Geoff , Han Linjiang
Published: October 2015

Premise of the study:

Rehmannia glutinosa (Scrophulariaceae) is used in traditional Chinese medicine. Microsatellite primers were developed and characterized for this species to evaluate its genetic diversity and population genetic structure.

Methods and Results:

Sixteen microsatellite loci were isolated from R. glutinosa using an enriched genomic library, and these markers were characterized in two wild populations of this species. The number of alleles per locus ranged from two to 20. A high genetic diversity was observed in two populations, with average observed heterozygosity of 0.812 and 0.794, and average expected heterozygosity of 0.802 and 0.814, respectively.

Conclusions:

Rehmannia glutinosa is an important medicinal resource. The genetic markers described in our study will be useful for future population genetic studies and molecular breeding programs on this species.
Précarité sociale et risque périnatal
Authors: Azria Élie
Published: October 2015

L’objet de cet article est l’examen au travers de la littérature épidémiologique des liens existant entre précarité sociale et risque périnatal. Après avoir montré les difficultés à donner de la précarité sociale une définition consensuelle et opératoire d’un point de vue épidémiologique, on y voit que celle-ci est associée dans des contextes variés à un accès aux soins périnatals dégradé et à un risque périnatal accru par rapport aux femmes vivant dans des conditions non précaires.
La persiana enrollable. Revisión del sistema constructivo y sus requisitos medioambientales
Authors: Martí N. , Araujo R.
Published: October 2015

El empobrecimiento de los filtros del hueco hace que su eficiencia medioambiental, integración en el sistema constructivo y cualidades compositivas y espaciales se vean drásticamente reducidas. La revisión de la persiana enrollable desde su evolución histórica como elemento fundamental de la transformación del hueco permite devolver al cerramiento y al hueco esa complejidad perdida y acercarnos a la necesaria tipificación de nuestras soluciones. La investigación de la persiana enrollable parte de las primeras patentes inglesas y francesas hasta llegar a España por medio de los Herederos de Ramón Múgica, en San Sebastián y Casas&Bardes, en Barcelona, con múltiples soluciones constructivas integradas en los huecos. Su concepción a principios del s. XIX difiere de la actual tanto a nivel de acondicionamiento climático como constructivo y permite valorar, a través del análisis de algunos ejemplos, el cumplimiento de sus prestaciones e integración en el hueco y discernir qué soluciones emergentes son las más óptimas.
An Infrastructure for Wireless Sensor-Cloud Architecture via Virtualization
Authors: Anandaraj S. P. , Poornima S.
Published: October 2015

A typical WSN contains spatially distributed sensors that can cooperatively monitor the environment conditions, like second, temperature, pressure, motion, vibration, pollution and so forth. WSN applications have been used in several important areas, such as health care, military, critical infrastructure monitoring, environment monitoring, and manufacturing. At the same time. WSN Have some issues like memory, energy, computation, communication, and scalability, efficient management. So, there is a need for a powerful and scalable high-performance computing and massive storage infrastructure for real-time processing and storing the WSN data as well as analysis (online and offline) of the processed information to extract events of interest. In this scenario, cloud computing is becoming a promising technology to provide a flexible stack of massive computing, storage, and software services in ascalable and virtualized manner at low cost. Therefore, sensor-cloud (i.e. an integrated version of WSN & cloud computing) infrastructure is becoming popular nowadays that can provide an open flexible, and reconfigurable platform for several monitoring and controlling applications.
Design, Architecture, and Security Issues in Wireless Sensor Networks
Authors: Shukla Piyush Kumar , Sharma Lokesh , Bhatele Kirti Raj , Sharma Poonam , Shukla Prashant
Published: October 2015

Wireless Sensor Networks (WSNs) provide a new paradigm for sensing and disseminating information from various environments, with the potential to serve many and diverse applications. In this chapter, we report the latest trends in WSN research, focusing on middleware technology and related areas, and including application design principles. We give an overview of WSNs and design aspects of applications, including existing research prototypes and industry applications. We describe the technology supporting these sensor applications from the view of system architecture and network communication. We then highlight outstanding issues and conclude with future perspectives on middleware technology.
A Comparative Study of Teachers' and Students' Use of Social Media for Interaction with Other People
Authors: Zaščerinska Jeļena , Ahrens Andreas
Published: October 2015

Economic crisis strongly influences teaching. To promote effectiveness and competitiveness of teaching in higher education, teachers' and students' use of social media for interaction with other people has to be analysed. The research question is as following: are there any similarities and differences between teachers' and students' use of social media for interaction with other people? The purpose of the research is to compare teachers' and students' use of social media for interaction with other people. The meaning of the key concepts of “social media” and “web technologies” is studied. Exploratory research is used. The empirical study was based on teachers' and students' case studies. Descriptive statistics was implemented for primary data analysis. The findings allow drawing the conclusions on the teachers' and students' use of social media for interaction with other people. A hypothesis is proposed. Directions of further research are formulated.
Identifying the Determinates of Entrepreneurial Intention
Authors: Khalique Muhammad
Published: October 2015

The prime aim of this study was to explore the determinants of entrepreneurial intention among undergraduate students at university level. This study employs attitude towards the behavior, subjective norm and perceived behavioral control as predictors and entrepreneurial intention as a dependent variable. The data were gathered through structured questionnaire. Respondents of this study were picked through convenience sampling technique. A total of 400 sets of questionnaire were distributed to the targeted respondents while 384 individuals were participated in the study. This study was a descriptive in nature. Most of the respondents showed their intention to be entrepreneur. This study will be a milestone for potential researchers. In future, researchers can conduct empirical studies on this topic.
Implementation of Robots Cooperating with Humans in Production Systems
Authors: Marčan Peter , Rofár Ján , Mičieta Branislav
Published: October 2015

This paper describes a new approach to robotics. The new trend in the field of robotics is human-robot cooperation. Manufacturers of robots as well as manufacturing plants are aware of that fact, hence it is expected to increase the robotics co-workers sale in the coming years. The article deals with the safety of humans and cooperating robots and consequently with application development using ROS (Robot Operating System).
Introduction of RFID System into Transport and Defining its Model of Return on Investment
Authors: Hricová Romana , Balog Michal
Published: October 2015

The article deals with the introduction of RFID technology to the broad gauge railway transportation. Interest in RFID technology is growing not only in the world but also in Slovakia so article is focused on the proposal on the transport of Fiat, where RFID system would be implemented for shipment of containers that are transported through Combined Transport Terminal Dobrá farther to the Russian market. Model calculation of return shows an interesting profitability and return on investment. In addition, the containers could be observed in real time, which is obviously a great advantage that the implementation of RFID technology provides.
Control of Activity of Aircraft Engines by Analysis of Wear Debris Particles in Terms of Shape and Size
Authors: Mihalčová Janka , Rimár Miroslav
Published: October 2015

The contribution deals with use of semi-automated method of magnetic separation of particles in order to control mechanical system of aircraft engines. There are three levels of machine wear characterized by means of wear debris particle analysis in the lubrication system of aircraft engines. The shape and size of wear debris particles formed due to machine wear arise immediately in case of wear change thus this method is extremely suitable to control mechanical system washed by lubricant. Analysis of actual samples of lubricating oils containing several types of wear debris at the same time resulted in finding out and characterizing the levels of wear, from standard up to critical one. The contribution describes typical types of aircraft engine lubrication system wear with allocation of the wear level to particular pictures of wear debris particles.
Robotic Arm with 7 DoF for Upper Limb
Authors: Jobbágy Boris , Šimšík Dušan , Rákay Róbert , Karchňák Ján
Published: October 2015

The article describes a design of robotic arm with 7 DoF for upper limb. In the first part there are described requirements for the robotic arm. Article continues with the biomechanical analysis of the upper limb, with the analysis of the ergonomic adjustable parameters and with the character of the required exercises which is the basis for the design of such device. The main part of the article describes and original solution of mechanical part of the robotic arm with 7 DoF actuated by pneumatic artificial muscles.
2DOF Controller Tuning
Authors: Viteckova Miluse , Vitecek Antonin
Published: October 2015

At present the two degrees of freedom (2DOF) controllers are more often available. These controllers enable to tune both from point of view of the desired variable and the disturbance variable as well. It allows increase the overall quality of control. For the tuning of the 2DOF controllers to date there are only a few suitable methods. This paper is devoted to the tuning of the 2DOF PI and PID controllers by the multiple dominant pole method (MDPM) for first order plants and integrating plants with time delay. It is an analytical method and it is shown that by the corresponding tuning of the 2DOF controllers it is possible to obtain the non-oscillatory servo and regulatory step responses without overshoots. The use is demonstrated in the example.
A Review of Bionic Technology for Drag Reduction Based on Analysis of Abilities the Earthworm
Authors: Gu Yun Qing , Fan Tian Xing , Mou Jie Gang , Jiang Lan Fang , Wu Deng Hao , Zheng Shui Hua
Published: October 2015

The earthworm is a common terrestrial animal, its physical structure and morphology characteristics are very distinctive. Through of imitation of the special abilities of earthworms, people can get the material to research on bionic technology, such as the jet, non-smooth surface, etc. It can provide the new design ideas for engineering technology. The study of earthworm body structure and its movement mechanism, can help people to find the drag reduction method in the process of movement. In addition, the earthworm non-smooth body surface, dorsal pore jet, surface lubrication, electroosmosis and its unique moving way form a good drag reduction effect. Therefore, research on earthworm is instructive for the development of bionic technology.
Heat and Mass Transfer in MHD Eyring-Powell Nanofluid Flow due to Cone in Porous Medium
Authors: Jayachandra Babu Macharla , Sandeep Naramgari , Raju Chakravarthula S.K.
Published: October 2015

In this paper, we analyzed the thermophoresis and Brownian motion effects on the boundary layer flow of a magnetohydrodynamic Eyring-Powell nanofluid over a permeable cone in the presence of buoyancy forces and suction/injection effects. The governing partial differential equations are transformed into set of non-linear coupled ordinary differential equations by using self-suitable transformations, which are then solved numerically using Runge-Kutta fourth order along with shooting technique. The obtained results present the effects of various non-dimensional governing parameters on velocity, temperature and concentration profiles. Also, enumerated and analyzed the friction factor, local Nusselt and Sherwood numbers. We presented dual solutions for suction and injection cases and found an excellent agreement of the present results with the existed studies under some special limited cases. Result indicates that dual solutions are available only for particular range of suction or injection parameter and Eyring-Powell parameter have tendency to enhance the heat transfer rate.
Chemically Reacting Radiative MHD Jeffrey Nanofluid Flow over a Cone in Porous Medium
Authors: Raju Chakravarthula S.K. , Jayachandra Babu Macharla , Sandeep Naramgari
Published: October 2015

The objective of this paper is to analyze the influence of thermal radiation and chemical reaction on the boundary layer flow of a magnetohydrodynamic Jeffrey nanofluid over a permeable cone in the presence of thermophoresis, Brownian motion effects. The set of non-linear governing partial differential equations are transformed into set of non-linear coupled ordinary differential equations by using self-suitable transformations, which are then solved numerically using Runge-Kutta fourth order along with shooting technique. The obtained results present the effects of various non-dimensional governing parameters on velocity, temperature and concentration profiles. Also, enumerated and analyzed the friction factor, local Nusselt and Sherwood numbers. We presented dual solutions in the presence and absence of the magneticfield and found an excellent agreement of the present results with the existed studies under some special limited cases. Result indicates that an increase in the buoyancy parameter increases the heat and mass transfer rate in the presence and absence of the transverse magneticfield and dual solutions exists only for certain range of magneticfield parameter.
Application of Micro-Arc Oxidation Technology in Die Magnesium Alloy Wheels in Mass Production
Authors: Zhang Zhan Ling , Zhang Yan Qin , Zhang Li , Pan Ai Qiong , Liu Jun
Published: October 2015

Micro-arc oxidation technology is a new type of metal surface treatment technology. With a large area of die casting magnesium alloy wheel surface treatment as an example, the practical production and application of micro-arc oxidation technology of magnesium alloy is discussed, Surface treatment technology production line is designed, The main equipment and process piping required for production line is introduced in detail. By the study of current and voltage which have a large effect on the craft of micro-arc to magnesium alloy, in the end a kind of electric parameters of micro-arc oxidation about magnesium alloy was optimized and film quality for testing. The micro-arc oxidation technology has been proved practically an appropriate technology for Mg alloy wheel hub and reference for the mass production used for a large area of magnesium alloy surface treatment technology and equipment design.
Dynamic Model of Material Removal Process in Through-Feed Centerless Grinding Based on the Lagrange Equation
Authors: Qi Cui , Chen Shi Jin , Ding Hui , Cheng Kai
Published: October 2015

Due to the unfixed state of the workpiece and the dissimilarity between sections in through-feed centerless grinding, the positions and orientations of the workpiece keep changing in the grinding process, which are coupled with the workpiece roundness generation. In this paper the positions and orientations of the workpiece are described by the dynamic equations obtained from Lagrange equation. And the homogeneous coordinate transformation is applied to present the profiles of the workpiece, grinding wheel and control wheel in the reference frame. Finally the time varying profile of the workpiece is obtained for the investigation of the material removal process in 3D space. The material properties of the workpiece, the wheels and the workrest combined with the geometric relationship of their profiles are utilized to calculate the interaction between them, including the three forces along the axes and the three moments about the axes.
Thermal Stress Analysis of Powder Metallurgy Sintering Process Based on ANSYS
Authors: Qiu Hui , Zhu Yong Gang , Zhang Li
Published: October 2015

Powder metallurgy is a technology process that the powder is pressed and sintered to get the metal and composite products. The sintering temperature is one of the main technology parameters of pressing sintering. In significant measure, the sintering temperature determines the organization and geometry size of the material, which directly affects the performance of the material. This paper takes magnesium powder metallurgy sintering material as the research object, studying the transient thermal analysis with the ANSYS finite element software, systematic researching the sinter temperature field and thermal stress field of sintered body in the sintering process, and observing in the corresponding distribution of stress field and deformation under different sintering temperature distribution graph. Temperature field and thermal stress field are the main factors affecting the quality of the sintered body in sintering process. Uneven temperature distribution will cause larger thermal stress. When the thermal stress exceeds a certain limit, the sample will be deformed. With the temperature increases, the sintering temperature difference increases, the stress distribution in the constantly changes. The stress and deformation is not entirely visible for sintered body, the deformation and cracking will be side by side in the sintering process. Therefore, theory of temperature field and thermal stress distribution are studied and discussed in certain sintering processing, the sintering process optimization can be designed to provide quantitative basis of the theoretical analysis.
Infulence of Chemical Composition and Metallographic Structure to Dimagnetic Stainless Steel
Authors: Zeng Qi Wen , Zhang Zhi Ming
Published: October 2015

A kind of rotating step motor is used in special environment, which has the character of single step angle great,single step rotating speed rangeing widely and output turque rangeing widely. To adapt the using environment and its working characteristics, the motor’s main parts of shell and front-backcovers are all made up of the stainless steel 1Cr18Ni9Ti, which has a good performance in diamagnetic and comperhensive mechanics. During the manufacture process, the 1Cr18Ni9Ti was found can be absorded by magnet. This paper researchs the influence of elements components and metallographic structure to the 1Cr18Ni9Ti by analyzing the element components and metallographic structure of several batches of materials.
A New Method for Copper Spherical Surface Lathing with High Speed Steel Cutting Tool
Authors: Chen Ze Fei , Zhang Lang
Published: October 2015

On the basis of uneven copper surface roughness during lathering in common CNC lather, analyze the cutting ways of copper spherical surface and the cutting layer different from cylindrical surface lathing. The cutting direction of cylindrical surface lathing is constant, and its cutting layer is too. However, the direction of spherical surface lathing varies along the tangent of its cutting point continually, and the working cutting edge angle and the working minor cutting edge angle of the cutting tool vary too, so the theoretical surface roughness is affected. The cutting layer of spherical surface lathing varies continually, so does the cutting depth of its every cutting point. Through analysis and experiments, prove that cutting force variety is caused by the gradient variety of cutting depth, which leads to increase of the surface rough and its unevenness. Based on the research result, design some new cutting path to improve the surface roughness of copper spherical surface lathing, and obtain good effect.
Fuzzy Comprehensive Evaluation for Road Base Material Selection Based on Analytic Hierarchy Process
Authors: Huang Xin Qing , Qiu Xin , Chen Lin Wu , Wu Jin Hong , Luo Xiao Hua
Published: October 2015

This paper conducted the EN-1 ionic liquid improved soil comparison and evaluation between the stabilization soil and the stabilized aggregate materials in order to analyze its economic cost and solve the issues of road base material selection with the multiple influence factors. Firstly analytic hierarchy process (AHP) was used to establish the hierarchical structure of the decision index and the weight of each indicator in an index layer. Secondly the fuzzy relation matrix of the evaluation criteria were determined by expert evaluation method, and then a comprehensive fuzzy evaluation model can be established for the selection of road base materials. Finally, based on the comprehensive sequencing of different materials derived from fuzzy mathematical calculations, the optimal selection can be achieved. The proposed evaluation model comprehended the availability of material, construction requirements, load capacity, durability, energy consumption, environment protection and material cost etc. This research provided a theoretical basis as well as an effective and practical solution for the future development of highway construction in China.
Mechanics Mechanism Analysis of Asphalt-Aggregate Interface Damage
Authors: Yang Qing , Xiao Shang Lin , Qiu Xin , Luo Xiao Hua , Wang Yu Jie
Published: October 2015

In the areas of South China, the asphalt pavement will appear various forms of water damages under the condition of vehicle loads and humid rainy environment. The interface of between aggregate and asphalt is the weaknesses position of the mixture internal structure, which will impose a significant influence on the service life of asphalt mixtures. However, the existing mesomechanics models of asphalt mixtures are almost based on the three-phase composite materials (asphalt mortar, aggregate, void) and have no enough consideration for the actual mechanics characteristics of the weak interface. It is no doubt that the effectiveness of the numerical simulation results will face a great challenge. The main purposes of this paper is to analyze and summary the relative basic characteristics of asphalt-aggregate interface including interface contact behavior, microstructure characterization methods, interface damage features and the macro-micro quantitative evaluation method of the interface damage The results show that the existing mechanical model ignores the asphalt-aggregate interface imperfect bonding, which make the asphalt-aggregate interface mechanical properties difficult to be perceived. Therefore, establishing a more rational micromechanical analysis model to predict asphalt macroscopic mechanical properties of asphalt mixtures will certainly be an urgent task and will provide a theoretical and scientific support for the optimization of asphalt mixture design.
Research on the Best Autofrettage Pressure of Ultra-High Pressure Valve Body
Authors: Ma Xiu Hua
Published: October 2015

This paper takes the ultra-high pressure (103.5MPa) valve body as the research object and adopts the finite element method to perform simulation analysis on the three bearing conditions involved with the valve body, i.e., autofrettage pressure, discharge and working pressure. The simulation shows identical results with the theoretical calculation. The relationship between the maximum equivalent stress and autofrettage pressure during the operation of the valve is obtained from the simulation results; therefore the best autofrettage pressure is determined. When determining the maximum value of autofrettage pressure, the maximum pressure, at which reverse yield does not happen, and the complete yield pressure shall be taken into consideration, with the smaller value of the two taken after comparison and analysis. When the size of the valve body is fixed at certain value, the best autofrettage pressure is not a fixed value, but it varies with the change of working pressure.
Experimental Study on Laser Transmission Joining between PA66GF and AISI304
Authors: Meng Dong Dong , Jiang Tao , Liu Hui Xia , Wang Xiao , Wu Yan Wei
Published: October 2015

Joining between polyamides (PA) and metals has potential applications in the industry. Based on PA66GF and AISI304, the experimental study of laser transmission joining of the dissimilar materials is conducted in this article. Firstly, comprehensive experiments of laser transmission joining between PA66GF and AISI304 are carried out by Nd: YAG pulsed laser source according to the central composite rotatable design method (CCRD). Secondly, the effects of the process parameters like voltage, joining speed and stand-off distance on the joint quality are analyzed by response surface methodology (RSM). Finally, mathematical models between the process parameters and the lap-shear strength and the joint width are established and based on which, the optimization of the joining process is done and the optimized results are predicted. The results show that the process parameters of laser transmission joining play a significant role in determining the joint quality; the predicted data of the models are in good agreement with the experimental results and can be of great help for the optimization of the joining process. As a result, this study could provide an effective instruction about how to choose the reasonable process parameters for enhancing the joining efficiency.
Analysis of Vibration Amplitude in High-Speed Cutting for Hardened Steel
Authors: Chen Guang Jun , Wang Liang , He Bai Ting , Kong Ling Guo , Zhou Xiao Qin
Published: October 2015

The cutting vibration has a great influence on the processing quality of Hardened steel. The research conducted in this paper is about how the cutting parameters influence the cutting vibration amplitude when the hardened steel is cut. The experiments were performed on CNC lathe CAK4085 with PCBN tool, where the cutting speed, feed rate, cutting depth and corner radius had been orthogonally combined. The cutting materials were hardened steel Cr12MoV and GCr15 whose hardness is HRC50-52 and HRC62-64. The cutting vibration amplitude under different group parameters was collected by electric eddy current sensors. An analysis about the influence rule of cutting parameters on cutting vibration amplitude had been made. With the increase of cutting speed, vibration amplitude will increase first, and then decrease. With the appropriate increase of feed rate, vibration amplitude will be reduced. With the increase of cutting depth and corner radius, vibration amplitude will both increase. This research can provide reference for improving cutting quality.
Variation in the Fiber Percentage in Specimens of Laminated Bamboo Guadua angustifolia
Authors: Takeuchi Caori Patricia , Estrada Martin , Linero Dorian Luis
Published: October 2015

Raw bamboo is a composite graded naturally material with variable distribution of fibers in the culm wall thickness and also in height. The strength and fiber volume fraction obtained in tests of round bamboo are very variable, while laminated bamboo has more uniform properties. The fiber volume fraction was determined in two groups of specimens of laminated bamboo Guadua angustifolia and also in two groups of bamboo clapboards. Although the average values of fiber volume fraction was around 45% for all cases, it was found that the coefficient of variation in the groups of specimens of laminated bamboo guadua was 6%, while in the groups of slats was 29%.
Gypsum Plaster Waste Recycling: Analysis of Calcination Time
Authors: de Moraes Rossetto Jaqueline Rosalí , Santos Correia Lucas , Henrique Geraldo Rodrigo , Camarini Gladis
Published: October 2015

The gypsum plaster is a material widely used in constructions around the world. It is a material with high versatility that can be applied from wall coverings to decorative ornaments. However, during its application in buildings, large amounts of waste materials are generated. The average values of waste during its application are higher than 45% of the gypsum amount used. A series of tests were conducted to develop a feasible methodology to reuse this waste material. The results collected at this stage indicated that it is possible to obtain a recycled product with low energy consumption. It was noted that after a certain number of procedures in which gypsum was subjected to recycling, there was a loss of workability; however, it did not present relevant changes in mechanical properties. This lack of workability avoids the recycled material maintain its properties in the fresh state as it is subjected to recycling. This work evaluates the calcination time of gypsum plaster waste for the production of a gypsum plaster with binder properties for using as components. The temperature of calcination was kept constant (150 °C), but the residence time in the stationary kiln was modified. The properties in the powder state (bulk density, fineness modulus, specific mass and sieve analysis), fresh state (mini-slump, setting times and kinetics of temperature) and in the hardened state (compressive strength and hardness) were analysed in order to have some answers about the performance of the recycled gypsum. In the fresh state, the recycled material showed good results for precast components. The initial setting times were good for all residence times and the final setting times for the material calcined in periods of 5 and 6 hours. In the hardened state, the best compressive strength results were obtained for all residence times, and hardness for calcination for 3, 4, 5 and 6 hours. All these results were satisfactory when compared to the commercial plaster took as reference. On the other hand, there was a lack of workability in those pastes indicating that an admixture is needed to adjust this property of the recycled material.
Study on the Pozzolanic Effect of Sugarcane Bagasse Ash from Taretan, Michoacán, Mexico, on a Portland Cement Mortar
Authors: Rodríguez Bucio J.L. , Reyes-Araiza José Luis , Alonso Guzmán Elia Mercedes , Manzano-Ramirez Alejandro , Ramírez-Jiménez R. , Martínez Molina W. , Cobreros-Rodríguez C. , Pérez Rea L.
Published: October 2015

Since the construction industry is responsible for 30% of the CO2 emissions, one way to reduce the impact of the construction activity is to substitute ordinary Portland cement by pozzolanic materials. The application of using agricultural waste in the production of pozzolanic material is technically feasible, due to the calcination of organic materials and leaving ashes with a fine particle size and high SiO2 content. In the present, it is discussed the pozzolanic effect of sugarcane bagasse ash (SCBA) from Taretan, Michoacán, Mexico, on the physical and mechanical properties of a portland cement mortar. Test specimens were prepared based on replacing sugarcane bagasse ash percentages of 5, 10, 15, 20 and 30 %, relative to the weight of cement. To validate the mechanical properties of the specimens, tensile, flexural and compressive strength was determine. The porosity of the mortar was determined by means of non-destructive ultrasonic testing of pulse rate and electrical resistivity. The contribution of this paper was determine the bond strength of an overlay mortar with SCBA bonded to the concrete substrate by pull-out tests. The results showed that the addition of the sugarcane bagasse ash improved the mechanical strength, adherence of the mortar to concrete, and decreases the porosity on large curing times. Hence, it is suggested the use of Portland pozzolan cement containing sugarcane bagasse ash pozzolan, with the added benefit on the use of agricultural waste.
Effect of Fiber and Starch Incorporation in Biodegradation of PLA-TPS-Cotton Composites
Authors: de Macedo José Ricardo Nunes , dos Santos Rosa Derval
Published: October 2015

Poly (lactic acid) (PLA) is a biodegradable and high-cost polymer which is nevertheless replacing the use of commodities in applications like packaging films, and is widely discarded in the environment. In this work, PLA was homogenized in a K-Mixer with different proportions of thermoplastic starch (TPS), a material with lower cost, and these mixtures were reinforced with natural cotton fibers, seeking to increase the tensile strength without compromising biodegradation. To evaluate the degradation behavior of PLA-TPS-cotton composites, tests were performed to measure the contact angle as well as the effect of hydrolysis and degradation in simulated soil. All the materials showed peak mass retention when removed from the water at 28 days and from the simulated soil at 14 days. The results showed that varying the content of TPS (0, 3 and 5%) caused increased water absorption and rate of degradation, but the fiber content (0, 10 and 20%) can distinguish the influence observed by incorporation of starch. The samples immersed in water presented retention values near those of the PLA matrix itself only for the ratio between fiber and TPS of 2:1 in mass percentage, showing the increased stability of the composite in contact with water.
Hexagonal Ferrite Fibres and Nanofibres
Authors: Pullar Robert C.
Published: October 2015

Hexagonal ferrites, or hexaferrites, are hugely important materials commercially and technologically, with common applications as permanent magnets, magnetic recording and data storage media, components in electrical devices operating at wireless frequencies, and as GHz electromagnetic wave absorbers for EMC, RAM and stealth technologies. Hexaferrites are all ferrimagnetic materials, and their magnetic properties are intrinsically linked to their crystalline structures, all having a strong magnetocrystalline anisotropy; that is the induced magnetisation has a preferred orientation within the crystal structure. They can be divided into two main groups: those with an easy axis of magnetisation (known as uniaxial), the hard hexaferrites, and those with an easy plane (or cone) of magnetisation (known as ferroxplana or hexaplana), soft ferrites. The common hexaferrite members are:M-type ferrites, such as BaFe12O19and SrFe12O19Z-type ferrites (Ba3Me2Fe24O41)Y-type ferrites (Ba2Me2Fe12O22)W-type ferrites (BaMe2Fe16O27)X-type ferrites (Ba2Me2Fe28O46)U-type ferrites (Ba4Me2Fe36O60)where Me = a small 2+ion such as cobalt, nickel or zinc, and Ba can be fully substituted by Sr. Generally, the M ferrites are hard, the Y, Z and U ferrites are soft, and the W and X ferrites can very between these two extremes, but all have large magnetisation (M) values.There is currently increasing interest in composite materials containing hexaferrite fibres. It had been predicted that properties such as thermal and electrical conductivity, and magnetic, electrical and optical behaviour will be enhanced in material in fibrous form. This is because a continuous fine fibre can be considered as effectively one-dimensional, and it does not behave as a homogeneously distributed solid. Although the intrinsic magnetisation of the material is unaffected, the effective magnetisation of an aligned fibre sample should be greater when a field is applied parallel with fibre alignment compared to when applied perpendicularly to fibre alignment. This feature was first demonstrated by the author for aligned hexaferrite fibres in 2006. This chapter will deal with progress in the manufacture and properties of hexaferrite fibres, from the first syntheses of BaM, SrM,Co2Y,Co2Z, Co2W, Co2X and Co2U micron-scale fibres by the author 12-15 years ago, to recent developments in M ferrite hollow fibres and nanofibres, and hexaferrite-coated CNTs (carbon nanotubes).The relative properties of all reported hexaferrite fibres are compared and summarised at the end of this chapter.
Super-Paramagnetic Nanoparticles with Spinel Structure: A Review of Synthesis and Biomedical Applications
Authors: Galvão Wesley S. , Neto Davino M.A. , Freire Rafael M. , Fechine P.B.A.
Published: October 2015

The study of ceramic materials has attracted the attention of many researchers due to the possibility of their use in nanotechnology. The spinel ferrites form a large group of materials with a broad range of applications. Some examples include electronic devices such as high-frequency transformer cores, antenna rods, induction-tuners, among many others. However, when the ferritic materials display superparamagnetic behavior, their potential for biological applications like drug delivery, hyperthermia, resonance magnetic imaging and magnetic separation, become amazingly high. Therefore, the superparamagnetism is a characteristic strongly desired for spinel ferrites. Since this phenomenon is size-dependent, the methodologies to synthesize these materials has emerged as a crucial step in order to obtain the desired properties. In this regarding, several synthetic processes have been developed. For example, co-precipitation is a fast and cheap method to synthesize superparamagnetic spinel ferrites. However, methodologies involving microwave, ultrasound or polymers frequently result in these kind of materials. Therefore, this review brings a brief historic introduction about spinel ferrites as well as essential concepts to understand their structure and magnetic properties. In addition to this, recent advances in synthesis and applications of the superparamagnetic spinel ferrites are mentioned. Contents of Paper
Oncogenic Transformation of Dendritic Cells and Their Precursors Leads to Rapid Cancer Development in Mice
Authors: Böttcher Jan P. , Zelenay Santiago , Rogers Neil C. , Helft Julie , Schraml Barbara U. , Reis e Sousa Caetano
Published: October 2015

Dendritic cells (DCs) are powerful APCs that can induce Ag-specific adaptive immune responses and are increasingly recognized as important players in innate immunity to both infection and malignancy. Interestingly, although there are multiple described hematological malignancies, DC cancers are rarely observed in humans. Whether this is linked to the immunogenic potential of DCs, which might render them uniquely susceptible to immune control upon neoplastic transformation, has not been fully investigated. To address the issue, we generated a genetically engineered mouse model in which expression of Cre recombinase driven by the C-type lectin domain family 9, member a (Clec9a) locus causes expression of the Kirsten rat sarcoma viral oncogene homolog (Kras)G12D oncogenic driver and deletion of the tumor suppressor p53 within developing and differentiated DCs. We show that these Clec9aKras-G12D mice rapidly succumb from disease and display massive accumulation of transformed DCs in multiple organs. In bone marrow chimeras, the development of DC cancer could be induced by a small number of transformed cells and was not prevented by the presence of untransformed DCs. Notably, activation of transformed DCs did not happen spontaneously but could be induced upon stimulation. Although Clec9aKras-G12D mice showed altered thymic T cell development, peripheral T cells were largely unaffected during DC cancer development. Interestingly, transformed DCs were rejected upon adoptive transfer into wild-type but not lymphocyte-deficient mice, indicating that immunological control of DC cancer is in principle possible but does not occur during spontaneous generation in Clec9aKras-G12D mice. Our findings suggest that neoplastic transformation of DCs does not by default induce anti-cancer immunity and can develop unhindered by immunological barriers.
A Lymphotoxin/Type I IFN Axis Programs CD8+ T Cells To Infiltrate a Self-Tissue and Propagate Immunopathology
Authors: Ng Dennis , Maître Blandine , Cummings Derek , Lin Albert , Ward Lesley A. , Rahbar Ramtin , Mossman Karen L. , Ohashi Pamela S. , Gommerman Jennifer L.
Published: October 2015

Type I IFNs (IFN-I) are cytokines that can mediate both immune suppression and activation. Dendritic cells (DC) are significant producers of IFN-I, and depending on the context (nature of Ag, duration of exposure to Ag), DC-derived IFN-I can have varying effects on CD8+ T cell responses. In this study, we report that in the context of a CD8+ T cell response to a self-Ag, DC-intrinsic expression of IFN regulatory factor 3 is required to induce optimal proliferation and migration of autoreactive CD8+ T cells, ultimately determining their ability to infiltrate a target tissue (pancreas), and the development of glucose intolerance in rat insulin promoter–glycoprotein (RIP-GP) mice. Moreover, we show that signals through the lymphotoxin-β receptor (LTβR) in DC are also required for the proliferation of autoreactive CD8+ T cells, the upregulation of VLA4/LFA1 on activated CD8+ T cells, and their subsequent infiltration into the pancreas both in vitro and in vivo. Importantly, the defects in autoreactive CD8+ T cell proliferation, accumulation of CD8+ T cells in the pancreas, and consequent glucose intolerance observed in the context of priming by LTβR−/− DC could be rescued by exogenous addition of IFN-I. Collectively, our data demonstrate that the LTβR/IFN-I axis is essential for programming of CD8+ T cells to mediate immunopathology in a self-tissue. A further understanding of the IFN-I/LTβR axis will provide valuable therapeutic insights for treatment of CD8+ T cell–mediated autoimmune diseases.