Key Engineering Materials Vol. 638

Abstract: Currently, the processes of developing new medical devices (in particular, patient specific guides for orthopedic surgery being of interest in our research), is hampered by the difficulty of correctly and efficiently quantifying and translating the specific medical requirements in terms of technical specifications. This is caused by the intrinsic difficulty of the demarche, but also by a complicated communication between surgeon and engineer given the different practical and research perspectives, specific constraints, motivation, evaluation criteria and professional language barrier. The advent and development of new technologies with applications in the medical field, such as robotics, haptic-based virtual and augmented reality, additive manufacturing, collaborative modeling, knowledge-based support decision systems, etc., make now possible to bridge the gap between surgeons’ ideas and needs and their practical materialization into new customized medical devices. The paper enrolls in this research trend, presenting a general framework for the development of an intelligent e-health platform, which provides in a collaborative environment the necessary knowledge and computer-aided tools for translating surgeons’ needs into technical specifications for the design and manufacturing of patient-specific guides for orthopedic surgery. These guides can be used in the minimally invasive surgical procedures and for reducing the x-ray radiation exposure during surgery, and for increasing accuracy in performing different types of specific orthopedic surgical procedures such as cutting, drilling, tapping and aligning, by transferring the tools trajectories from computer-aided planning to surgery.

Abstract: The paper presents the investigations made on samples taken from the related rotor blade of an hospital cooling equipment.The failure analysis was made in order to find if the failure appear because the metallic material used or was functional problem.The objectives of our analysis and techniques used are described below:determining the chemical composition by optical emission spectrometry;determining the hardness of the material;metallographic analysis by optical microscopy;micro compositional and microstructural analysis by scanning electron microscopy (SEM) and by microanalysis, energy dispersive X-ray (EDAX). Research has highlighted the quality of piece elaboration and casting, which led to a long life of its use.

Abstract: In the last time, material engineering in lately developed the design and processing technology of materials in well-defined goals. Thus, they designed and achieved the metal alloys for use in strong fields required mechanical shock using methods of surface engineering. In this direction, we have developed very superficial deposition techniques by thermal spray of ceramic and metal powders, both for hard coating and to protect surfaces in refractory environments. In a controlled manner, can form new structures, which leads to an improvement in the tribological properties of the coatings obtained. In this paper are described experimental results obtained after the tests of resistance to mechanical shock testing of metal-ceramic coatings on forged titanium support. We analyzed the behavior of thermal deposited layers of ZrO2 stabilized with 8% Y2O3 and Al2O3 after applying mechanical shock test and scratch test. These materials were analyzed in terms of structural, of mechanical properties and adhesion of the surface layers using electron microscopy, X-ray diffraction, Charpy device, CETR UMT-2 tribometer. The results showed that the materials investigated have a stratified columnar structure, shows lamellar and intra - lamellar cracks and pores formed between neighbor "splat's". From microscopic analysis, after these tests, it was observed that the thermal deposited layers were not separated and there was a fingerprint on their surface. The experimental results show that the new structures obtained presents much better mechanical properties compared to the material, forged titanium, no deposit.

Abstract: In dental care is necessary to isolate the tooth the oral environment (saliva, tongue, cheek, etc) with some type of retractor. This work aimed to propose a new model of instrumental low cost that assists in dental treatment. The instrumental was virtually designed and tested with the characteristics of the materials used in its manufacture: Solid stainless steel wires of 7 mm, acrylic resin and steel tape. To simulate its functionality was modeled a mouth with the actual measurements via the free software Blender 2.49b. To evaluate the simulation results of the test type black box, where you can observe the operation of the simulator were used. After testing various virtual instruments with the same measurements to assess its performance were made clinically. It was concluded in the simulation and clinical tests that the instrument is stable and performs the removal of anatomical structures adjacent to the tooth, even in cases of patients with positive macroglossia can be used for different types and sizes of arches, in the absence of any tooth can be fixed in any tooth, getting the desired position by professional optimizing the same time.

Abstract: The paper presents the results of research conducted to determine the causes that led to the fracture of a motor shaft component from an electric surgical motor used in orthopedic surgery.The chemical and structural analysis emphasized a structure rich in complex silicate and sulfides inclusions. They form areas of weakness, acting like stress concentrators which induce fatigue shaft breakage. Their high density and non-uniform shape and distribution suggest a non-adequate technology of making and casting of steel, destinated to work in difficult conditions and having an important operational role.

Abstract: Ti alloys are applied extensively in several fields, particularly in the aerospace, chemical, dental and medical industries, due to their outstanding properties. Microstructure changes in commercial-purity titanium (CP-Ti) during open flame thermal shock and X-ray analysis were investigated. Water quenching of compact Cp-Ti has yielded martensitic-type laths and fishbone-type twinned microstructures. The microstructure of cast samples displays a martensitic structure and heat-treated samples shows a microstructure composed of α/α^‘phase. Several types of phases and crystallographic lattice were detected using XRD. Samples investigated were supposed to a heating over than 1500°C and cooled in two ways: by air and by water. SEM images are taken in comparison for studying the morphology and microstructure of alloys.

Abstract: The Attention Deficit Hyperactivity Disorder (ADHD) is the most common disorder among children in the school. Children with ADHD have more difficulty learning the discipline of mathematics. Recent studies showed that the use of computer games as a tool to aid evaluation of mathematical concepts can provide twice more solutions to problems than conventional methods. Several studies also showed that the colors can significantly affect the attention of children with ADHD. Therefore, this paper describes the development of the computerized game with red-green axis colors to help the assessment the initial concept of math in the children with ADHD. The game developed was produced using Blender 3D graphical tool. The developed game was validated by math teachers. They evaluated if the concept of math were presented clearly and objective. The game also was evaluated by professionals on software development process which assessed the functional requirements. The developed game has criteria recommended by APA (American Psychological Association) to retain the attention of hyperactive and allow the evaluation of their actual knowledge of math concepts.

Abstract: Nowadays the use of Virtual Reality (VR) based surgical simulators or training environments is becoming more and more spread in the medical world. These are usually dedicated to the development and improvement of novice trainees’ skills by helping them to learn different surgical techniques, to use proper instrumentation or to practice surgical protocols, but also in the training of expert surgeons for conserving their skills, for planning or rehearsing new, complicated or rare procedures. In this general context of interest, our paper aims at answering the following questions: What are the main requirements for a haptic device in order to be successfully used in the virtual training of orthopedic surgeons What requirements are mandatory to be included in an orthopedic surgery haptic-based training application for providing a realistic user’s experience These are legitimate questions considering that surgical education can really benefit the advantages offered by such virtual simulators only if they can satisfy a list of requirements among which high level of immersion and interactivity, realistic 3D virtual models and constraints of anatomical structures, good correspondence between real and simulated cases (i.e. a natural ‘behavior’ and ‘feeling’ of simulated anatomy). The focus of the literature review presented in this paper will be on orthopedic VR simulators for drilling, sawing and fixing implants screws, pins and plates, with an emphasize on devices’ characteristics and applications features. This study enrolls in the trend of improving user’s immersion experience at a cost as low as possible, representing the basis on which an innovative and affordable haptic device and an application for training basic orthopedic surgical skills are proposed for development in further research.

Abstract: The paper presents the dimensional aspects of a generic spinal cage build up from PA2200 powder. The cage was manufactured by means of selective laser sintering (SLS) technology, on Formiga P100 machine. The geometric model of spinal cage was designed in SolidWorks by taking into account the requirements that have to be fulfilled by such an implant. The dimensional aspects refer to geometric dimensions along X, Y and Z axes measured on sample parts, when these were placed on a 4x4 matrix on the building plane. The measurements were conducted using a digital caliper having a precision of 0.01, and were presented together with the nominal dimension of the CAD model. In conclusion, some qualitative aspects regarding the setting of the scaling factors were underlined.

Abstract: MgB₂ is a candidate for the fabrication of magnetic coils used in medical applications. Our review indicate that oxide additions based on the rare earth or metalloid elements show improvement of the MgB₂ critical current density (J_c) and the irreversible magnetic field (H_irr) without significantly affecting the critical temperature (T_c) However, the characteristics of the additions and the technological approaches show a strong influence in controlling superconducting properties. Both additions and the technology need a careful and complex optimization in order to enhance the J_c and H_irr.