Inductive hot-pressing of titanium and titanium alloy powders

Inductive hot-pressing is a field-assisted sintering process (FAST) in which an electrical current is used to enhance the densification of the powder. Inductive hot-pressing could be employed to enable titanium powder to reach a higher density in less time than the pressing and sintering process. In this study, titanium and titanium alloy powders with different features were processed by means of inductive hot-pressing. The influence of processing temperature on density, microstructure, quantity of interstitial elements and hardness was investigated. Generally, practically fully dense materials were obtained without any carbon pick-up, even if the materials were in contact with the graphite matrix during processing. Nevertheless, there was an increment of the nitrogen content and some oxygen pick-up, especially for the powders with smaller particle size. Hardness is not significantly affected by the pressing temperature, but it strongly depends on the amount of interstitials.The authors are thankful for the financial support from Comunidad de Madrid through the ESTRUMAT (S-2009/MAT-1585) project and from the Spanish Ministry of Education through the R&D MAT2009-14448 ProjectPublicad

Wire Harness Assembly Process Supported by Collaborative Robots: Literature Review and Call for R&D

The wire harness assembly process is a complicated manufacturing activity, which is becoming more complex because of the evolving nature of mechatronic and electronic products that require more connectors, sensors, controllers, communication networking, etc. Furthermore, the demand for wire harnesses continues to grow in all industries worldwide as the majority of equipment, appliances, machinery, vehicles, etc., are becoming "smart" (i.e., more mechatronic or electronic). Moreover, most of the wire harness assembly process tasks are done manually, and most of these are considered non-ergonomic for human assembly workers. Hence, the wire harness manufacturing industry is faced with the challenge of increasing productivity while improving the occupational health of its human assembly workers. The purpose of this paper is to conduct a literature review exploring the state of the use of collaborative robots in the wire harness assembly process due to their potential to reduce current occupational health problems for human assembly workers and increase the throughput of wire harness assembly lines, and to provide main findings, discussion, and further research directions for collaborative robotics in this application domain. Eleven papers were found in the scientific literature. All papers demonstrated the potential of collaborative robots to improve the productivity of wire harness assembly lines, and two of these in particular on the ergonomics of the wire harness assembly process. None of the papers reviewed presented a cost-benefit or a cycle time analysis to qualitatively and/or quantitatively measure the impact of the incorporation of collaborative robots in the wire harness assembly process. This represents an important area of opportunity for research with relevance to industry. Three papers remark on the importance of the integration of computer vision systems into a collaborative wire harness assembly process to make this more versatile as many types of wire harnesses exist. The literature review findings call for further research and technological developments in support of the wire harness manufacturing industry and its workers in four main categories: (i) Collaborative Robotics and Grippers, (ii) Ergonomics, (iii) Computer Vision Systems, and (iv) Implementation Methodologies

Study of Compaction and Ejection of Hydrided-Dehydrided Titanium Powder

Three similar varieties of pure Ti hydride-dehydried (HDH) powders were tested for the understanding of the variables that have an influence on the compaction process of Ti powders. The study shows that small differences in the characteristics of the powders lead to very different behaviours in the compaction stage. Compressibility curves, friction with the die walls and ejection forces are discussed in this study. The results are compared with a commercial iron powder as a reference to complete the discussion, as well as to show the enhancements and modifications that should be performed in Ti powders to design an optimized powder suitable for being pressed in an industrial process.The authors want to acknowledge the contribution and effort of Mr. Paul-Émile Mongeon from Industrial Materials Institute (IMI, Canada), as well as for his teaching and advises during the use of Powder Testing Center located at IMI. Shirley Mercier from IMI and Dr. Begoña Ferrari from Instituto de Cerámica y Vidrio (ICV, Spain), are also acknowledged for their contribution to the experimental work. Authors want to acknowledge Fundación Carlos III and Instituto Álvaro Alonso Barba for the funds supplied during the stay at IMI of P.G. Esteban, and the Spanish Ministry of Education for the funds provided for the research thought the I+D project MAT2006-02458.Publicad

Study of the properties of low-cost powder metallurgy titanium alloys by 430 stainless steel addition

Titanium is a lightweight metal with an outstanding combination of properties which make it the material of choice for many different applications. Nonetheless, its employment at industrial level is not widespread due to higher production costs with respect to competitor metals like steel and aluminium. In this work the production of low-cost titanium alloys is attempted by combining the utilisation of a powder metallurgy process and cheap alloying elements (i.e. commercial 430 stainless steel powder optimised for the powder metallurgy industry). Low-cost titanium alloys are fabricated by blending elemental titanium with stainless steel. The behaviour of the powders as well as that of the sintered materials are analysed and compared to that of a master alloy addition Ti6Al4V alloy. The produced low-cost titanium alloys show comparable properties to both wrought and powder metallurgy titanium alloys and, therefore, they are proposed as an alternative to obtain structural component made out of titanium alloys.The authors want to acknowledge the financial support from the Spanish Ministry of Science through the R&D Projects MAT2012-38650-C02-01, and from Regional Government of Madrid through the ESTRUMAT (S2009/MAT-1585) projec

¿CÓMO DESCANSA EL PACIENTE ONCOHEMATOLÓGICO EN EL HOSPITAL?

The nursing profession has an image stereotyped by society; the vision of the paradigm of the categorization dominating their training. That is the reason why it is interesting to know what the nurses think about their own discipline through the study of the elements of the nursing methaparadigm while comparing whether or not the specialty of the area modifies our perspective. Objective: To analyze and compare the nurse perspective on the elements of the metaparadigm among surgical nurses and medical nurses. Method: Comparative, observational, cross-sectional study. Using a questionnaire of our own elaboration between April - May, 2006. Results: 40 nurses of the surgical area and 61 of the medical area. Age 38±9 in surgery, 34,5±9 in medicine. Years of work experience: 16±11 and 12±8. Henderson Model guided their training. For the most part, they identify themselves with nursing definitions based on Henderson, health based on Erickson, environment based on Roy and Henderson and person founded on Travelbee.  Conclusions: The nursing areas studied do not modify the perspective on the elements of the methaparadigm.  El descanso nocturno es imprescindible para el bienestar físico y psíquico de toda persona y una inadecuada cobertura de esta necesidad influye negativamente en el paciente y altera su calidad de vida. El insomnio definido como ”una deficiencia persistente en la cantidad del sueño que afecta a la normal actividad y bienestar del individuo” es una queja frecuente entre los pacientes hospitalizados; motivo que justifica la necesidad de una atención especial a este problema.   Nos planteamos como objetivos identificar qué factores afectan en el descanso nocturno y saber si el personal de enfermería  conoce estos factores.   Se trata de un estudio descriptivo transversal realizado en las unidades de hematología y oncología durante el mes de marzo de 2008. Para recoger los datos elaboramos una encuesta para los pacientes y otra para el personal de enfermería.    El 91% de la muestra respondió que se despertaba durante la noche en el hospital y el 40% lo hace más de tres veces. Los factores que más alteran el descanso del paciente son los factores psicológicos (preocupación por la enfermedad, por la familia y el aburrimiento durante la hospitalización).   Como conclusiones destacamos que tanto enfermería como pacientes coinciden en que no se duerme en el hospital. El personal de enfermería demostró tener una buena percepción de las causas principales de insomnio de los pacientes. Ambos han coincidido en cómo los factores psicológicos influyen en el patrón de reposo/sueño.   Por ello sería importante que el personal de enfermería dedicara especial atención al manejo de los factores psicológicos a través de distintas técnicas

DEVELOPMENT OF A SCADA SYSTEM FOR ACCESS, PROCESSING AND SUPERVISION OF DATA COMING FROM A WIRELESS SENSORS NETWORK IN AGRO-ENVIRONMENTAL APPLICATIONS

Wireless sensors networks appeared in the 1970’s for military and industrial use. They have since undergone a major evolution, particularly since the 90’s, thanks to the improvements in wireless communications. These changes have allowed them to participate in a wide variety of applications in different sectors such as agriculture and environment. This paper shows the development of a SCADA application programmed with LabVIEW® 8.6 (National Instruments), which allows management of data received by wireless sensors networks through a friendly interface for users. For the application shown in this paper we have worked with a MEP 510 sensors network (Crossbow). The functionalities implemented are the following: Network configuration; Data storage into database; Statistical processing of historical data with polynomial adjustment and spline interpolation; Visualization by data graphics in real time and historical data; Visualization of 2D intensity diagrams from the spatial distribution of sensors; and Creation of a users registry system that allows, depending on the category assigned, receiving or not access privileges in the application. As a complement we have developed the possibility of remote access. Sensors network implemented and the applications developed have been checked by operational tests for each functionality, as well as sensors joining and leaving the network situations, range of variables and working modes. The results obtained show the robustness of the SCADA application and the limitations of wireless sensors networks operating on field conditions

Mechanical properties and microstructural evolution of vacuum hot-pressed titanium and Ti-6Al-7Nb alloy

Hot-pressing is a powder metallurgy process where loose powder is loaded into a mould, usually of graphite, and sintered by the simultaneous application of high temperature and pressure. In this study elemental titanium and Ti&-6Al&-7Nb alloy powders are hot-pressed under different conditions in order to study the influence of the processing parameters on the microstructure and mechanical properties. The samples are characterised in terms of relative density, microstructure, XRD, percentage of interstitials, three-point bending test and hardness. Relative densities as high as 99% are obtained, the oxygen and carbon content remains almost constant but nitrogen percentage increases. This is due to the interaction with the BN coated mould and leads to the formation of a reacted layer in the surface, composed by different titanium compounds, which greatly affect the mechanical properties. Nevertheless, the removal of this reacted layer leads to an important improvement of the ductility, especially for elemental titanium.The authors are grateful for the financial support from the Comunidad de Madrid through the ESTRUMAT (S-2009/MAT–1585) project and from the Spanish Ministry of Education through the R&D Project MAT2009-14448-C02-02.Publicad

A Comparative Study of Fracture Toughness at Cryogenic Temperature of Austenitic Stainless Steel Welds

The ITER magnet system is based on the "cable-in-conduit" conductor (CICC) concept, which consists of stainless steel jackets filled with superconducting strands. The jackets provide high strength, limited fatigue crack growth rate and fracture toughness properties to counteract the high stress imposed by, among others, electromagnetic loads at cryogenic temperature. Austenitic nitrogen-strengthened stainless steels have been chosen as base material for the jackets of the central solenoid and the toroidal field system, for which an extensive set of cryogenic mechanical property data are readily available. However, little is published for their welded joints, and their specific performance when considering different combinations of parent and filler metals. Moreover, the impact of post-weld heat treatments that are required for Nb3Sn formation is not extensively treated. Welds are frequently responsible for cracks initiated and propagated by fatigue during service, causing structural failure. It becomes thus essential to select the most suitable combination of parent and filler material and to assess their performance in terms of strength and crack propagation at operation conditions. An extensive test campaign has been conducted at 7 K comparing tungsten inert gas (TIG) welds using two fillers adapted to cryogenic service, EN 1.4453 and JK2LB, applied to two different base metals, AISI 316L and 316LN.The authors would like to express their thanks to Dr. Arman Nyilas (in memorian) for the contributions made in this work

Magnetic and morphological characterization of Nd2Fe14B magnets with different quality grades at low temperature 5-300 K

An increasing number of cryogenic devices may benefit from the use of Nd2Fe14B permanent magnets. However, it is necessary to precisely know their behavior because magnetization varies significantly due to Spin Reorientation Transition. In this work, magnetic and morphological characterization of Nd2Fe14B commercial polycrystalline magnets with different quality grades from 5 to 300 K is provided. A set of magnets ranging from N35 to N52 quality have been analyzed. Mean grain dimension as well as material composition elements are provided. Higher quality magnets show smaller mean grain dimensions. Regarding cryogenic temperatures, the well know spin transition effect appears in all the magnets as expected, however, the transition temperature occurs at different temperatures in a range from 112 to 120 K which is lower than those obtained for single crystal samples. Moreover, the relative variation of the remanence from 300 to 5 K is lower than 4% while the maximum expected variation is in average 11%. As extra information, the same analyzes are provided for additional quality grades N40M, N40S, N40SH and N40UH.The research leading to these results has received funding from the European Community's Seventh Framework Programme ([FP7/2007-2013]) under grant agreement n° 263014