499 research outputs found

    Human resources and manufacturing: where and when should they be aligned?

    Get PDF
    Purpose – The aim of this study is to analyse the effect that a horizontal fit between two functions (human resources and manufacturing) has on firm performance, distinguishing between fit in objectives and fit in achievements. Design/methodology/approach – This study uses 144 double surveys, addressed to two different respondents per company. Structural equations modelling was used to investigate the mediating role of fit in achievements in the relationship between fit in objectives and performance. Findings – The study provides evidence of the particular way in which the two components of horizontal fit that we distinguish (fit in objectives and fit in achievements) impact on performance: fit in objectives has an indirect effect on performance, which is fully mediated by the fit in achievements. The results also show that environmental dynamism has a significant impact on both the advantages and drawbacks of fit. Practical implications – By highlighting the importance of both levels of horizontal fit and distinguishing between them, this paper calls upon human resources (HR) and manufacturing managers to show a greater understanding of the key dimensions common to both areas. Originality/value – This study analyses horizontal fit by developing a framework of priorities in HR management (HRM) similar to that traditionally used in production management. In particular, it adapts the framework of production competence to the area of HRM to study the fit between the two functional strategies. This study also supports the value chain model proposed by Porter (1985)

    Cellulose-Based Nanofibers Processing Techniques and Methods Based on Bottom-Up Approach-A Review

    Get PDF
    In the past decades, cellulose (one of the most important natural polymers), in the form of nanofibers, has received special attention. The nanofibrous morphology may provide exceptional properties to materials due to the high aspect ratio and dimensions in the nanometer range of the nanofibers. The first feature may lead to important consequences in mechanical behavior if there exists a particular orientation of fibers. On the other hand, nano-sizes provide a high surface-tovolume ratio, which can have important consequences on many properties, such as the wettability. There are two basic approaches for cellulose nanofibers preparation. The top-down approach implies the isolation/extraction of cellulose nanofibrils (CNFs) and nanocrystals (CNCs) from a variety of natural resources, whereby dimensions of isolates are limited by the source of cellulose and extraction procedures. The bottom-up approach can be considered in this context as the production of nanofibers using various spinning techniques, resulting in nonwoven mats or filaments. During the spinning, depending on the method and processing conditions, good control of the resulting nanofibers dimensions and, consequently, the properties of the produced materials, is possible. Pulp, cotton, and already isolated CNFs/CNCs may be used as precursors for spinning, alongside cellulose derivatives, namely esters and ethers. This review focuses on various spinning techniques to produce submicrometric fibers comprised of cellulose and cellulose derivatives. The spinning of cellulose requires the preparation of spinning solutions; therefore, an overview of various solvents is presented showing their influence on spinnability and resulting properties of nanofibers. In addition, it is shown how bottom-up spinning techniques can be used for recycling cellulose waste into new materials with added value. The application of produced cellulose fibers in various fields is also highlighted, ranging from drug delivery systems, high-strength nonwovens and filaments, filtration membranes, to biomedical scaffolds.This research was funded by CONEX-Plus program of Universidad Carlos III de Madrid and the European Commission through the Marie-Sklodowska Curie COFUND Action (Grant Agreement No 801538). The authors also appreciate the financial support received from AEI (Ministerio de Ciencia e Innovación of Spain, PID2020-112713RB-C22]; the Universidad Carlos III de Madrid due to Fondos de Investigación of Fco. Javier González Benito [2012/00130/004] and the strategic Action in Multifunctional Nanocomposite Materials [Code: 2011/00287/003]

    Preparation of cellulose acetate film with dual hydrophobic-hydrophilic properties using solution blow spinning

    Get PDF
    Solution blow spinning (SBS), a processing method alternative to electrospinning, where pressured air is used instead of an electric field, was used in this work for the preparation of cellulose acetate (CA) materials. The sequential use of SBS to produce a double-layered film is also investigated. Mixtures of acetone with acetic acid or N,N-dimethylformamide (DMF) were studied as systems for polymer solution preparation. The type of produced material (flat film or multi-structured membranes constituted from submicrometric fibers with beads), its thermal properties, crystallinity, and morphology are more dependent on the solvent system than other SBS processing parameters. Roughness and porosity of differently produced materials influence wettability measured by the contact angle, which ranges in this work from approx. 69.8 degrees ± 3 degrees for a flat film to 104 degrees ± 5 degrees for fibrous material. Finally, a double-layered film, prepared by sequential SBS of individual layers different in terms of wettability, renders a standalone film of dual wettability, with one side hydrophobic and the other hydrophilic.This work was financially supported by CONEX-Plus program of Universidad Carlos III de Madrid (UC3M) and the European Commission through the Marie-Sklodowska Curie COFUND Action (Grant Agreement No 801538). Authors also appreciate the financial support received from AEI, The Ministry of Science and Innovation of Spain [PID2020-112713RB-C22 and –C21], Universidad Carlos III de Madrid, Funds for Investigation of Fco. Javier González Benito [2012/00130/004] and the strategic Action in Multifunctional Nanocomposite Materials [ 2011/00287/003]

    Gestión de ideas innovadoras

    Get PDF
    El trabajo de fin de grado que se va a definir detalladamente en esta memoria, trata de poner de manifiesto muchos de los conocimientos que he adquirido a lo largo de la carrera, aplicándolos en un proyecto real. Se ha desarrollado una plataforma capaz de albergar ideas, escritas por personas de todo el mundo que buscan compartirlas con los demás, para que estas sean comentadas, valoradas y entre todos poder mejorarlas. Estas ideas pueden ser de cualquier ámbito, por tanto, se da la posibilidad de clasificarlas en las categorías que mejor encajen con la idea. La aplicación ofrece una API RESTful muy descriptiva, en la que se ha identificado y estructurado cada recurso, para que a través de los “verbos http” se puedan gestionar todos los elementos de una forma fácil y sencilla, independientemente del cliente que la utilice. La arquitectura está montada siguiendo el patrón de diseño modelo vista-controlador, utilizando las últimas tecnologías del mercado como Spring, Liferay, SmartGWT y MongoDB (entre muchas otras) con el objetivo de crear una aplicación segura, escalable y modulada, por lo que se ha tenido que integrar todos estos frameworks. Los datos de la aplicación se hacen persistentes en dos tipos de bases de datos, una relacional (MySQL) y otra no relacional (MongoDB), aprovechando al máximo las características que ofrecen cada una de ellas. El cliente propuesto es accesible mediante un navegador web, se basa en el portal de Liferay. Se han desarrollado varios “Portlets o Widgets”, que componen la estructura de contenido que ve el usuario final. A través de ellos se puede acceder al contenido de la aplicación, ideas, comentarios y demás contenidos sociales, de una forma agradable para el usuario, ya que estos “Portlets” se comunican entre sí y hacen peticiones asíncronas a la API RESTful sin necesidad de recargar toda la estructura de la página. Además, los usuarios pueden registrarse en el sistema para aportar más contenidos u obtener roles que les dan permisos para realizar acciones de administración. Se ha seguido una metodología “Scrum” para la realización del proyecto, con el objetivo de dividir el proyecto en tareas pequeñas y desarrollarlas de una forma ágil. Herramientas como “Jenkins” me han ayudado a una integración continua y asegurando mediante la ejecución de los test de prueba, que todos los componentes funcionan. La calidad ha sido un aspecto principal en el proyecto, se han seguido metodologías software y patrones de diseño para garantizar un diseño de calidad, reutilizable, óptimo y modulado. El uso de la herramienta “Sonar” ha ayudado a este cometido. Además, se ha implementado un sistema de pruebas muy completo de todos los componentes de la aplicación. En definitiva, se ha diseñado una aplicación innovadora de código abierto, que establece unas bases muy definidas para que si algún día se pone en producción, sirva a las personas para compartir pensamientos o ideas ayudando a mejorar el mundo en el que vivimos. ---ABSTRACT---The Final Degree Project, described in detail in this report, attempts to cover a lot of the knowledge I have acquired during my studies, applying it to a real project. The objective of the project has been to develop a platform capable of hosting ideas from people all over the world, where users can share their ideas, comment on and rate the ideas of others and together help improving them. Since these ideas can be of any kind, it is possible to classify them into suitable categories. The application offers a very descriptive API RESTful, where each resource has been identified and organized in a way that makes it possible to easily manage all the elements using the HTTP verbs, regardless of the client using it. The architecture has been built following the design pattern model-view-controller, using the latest market technologies such as Spring, Liferay, Smart GWT and MongoDB (among others) with the purpose of creating a safe, scalable and adjustable application. The data of the application are persistent in two different kinds of databases, one relational (MySQL) and the other non-relational (MongoDB), taking advantage of all the different features each one of them provides. The suggested client is accessible through a web browser and it is based in Liferay. Various “Portlets" or "Widgets” make up the final content of the page. Thanks to these Portlets, the user can access the application content (ideas, comments and categories) in a pleasant way as the Portlets communicate with each other making asynchronous requests to the API RESTful without the necessity to refresh the whole page. Furthermore, users can log on to the system to contribute with more contents or to obtain administrator privileges. The Project has been developed following a “Scrum” methodology, with the main objective being that of dividing the Project into smaller tasks making it possible to develop each task in a more agile and ultimately faster way. Tools like “Jenkins” have been used to guarantee a continuous integration and to ensure that all the components work correctly thanks to the execution of test runs. Quality has been one of the main aspects in this project, why design patterns and software methodologies have been used to guarantee a high quality, reusable, modular and optimized design. The “Sonar” technology has helped in the achievement of this goal. Furthermore, a comprehensive proofing system of all the application's components has been implemented. In conclusion, this Project has consisted in developing an innovative, free source application that establishes a clearly defined basis so that, if it someday will be put in production, it will allow people to share thoughts and ideas, and by doing so, help them to improve the World we live in

    Polymeric materials with antibacterial activity: A review

    Get PDF
    Infections caused by bacteria are one of the main causes of mortality in hospitals all over the world. Bacteria can grow on many different surfaces and when this occurs, and bacteria colonize a surface, biofilms are formed. In this context, one of the main concerns is biofilm formation on medical devices such as urinary catheters, cardiac valves, pacemakers or prothesis. The development of bacteria also occurs on materials used for food packaging, wearable electronics or the textile industry. In all these applications polymeric materials are usually present. Research and development of polymer-based antibacterial materials is crucial to avoid the proliferation of bacteria. In this paper, we present a review about polymeric materials with antibacterial materials. The main strategies to produce materials with antibacterial properties are presented, for instance, the incorporation of inorganic particles, micro or nanostructuration of the surfaces and antifouling strategies are considered. The antibacterial mechanism exerted in each case is discussed. Methods of materials preparation are examined, presenting the main advantages or disadvantages of each one based on their potential uses. Finally, a review of the main characterization techniques and methods used to study polymer based antibacterial materials is carried out, including the use of single force cell spectroscopy, contact angle measurements and surface roughness to evaluate the role of the physicochemical properties and the micro or nanostructure in antibacterial behavior of the materials

    PVDF/BaTiO3/carbon nanotubes ternary nanocomposites: Effect of nanofillers and processing

    Get PDF
    Ternary thermoplastic systems based on poly(vinylidene fluoride), PVDF, filled with barium titanate, BaTiO3, submicrometric particles and carbon nanotubes, CNT, were prepared. Their structure and morphology were studied as a function of composition and finally correlated with thermal and mechanical properties. High energy ball milling, HEBM, under cryogenic conditions and subsequent hot pressing were used to obtain films with quite uniform dispersion of the nanofillers. The presence of BaTiO3 particles and CNT did not modify the thermodegradation mechanism of the PVDF. However, enough amount of BaTiO3 seemed to inhibit the volatility of the products of pyrolysis, hindering the decomposition of PVDF. The presence of CNT favored the PVDF thermodegradation probably due to improved heat transmission by an increase in the thermal conductivity. Variations in PVDF thermal transitions were more dependent of processing conditions. Improvements in the mechanical properties of PVDF were ascribed to a reinforcing effect of the fillers. This effect only happened below the fraction of percolation of CNT, pointing out that CNT reinforce through an optimum load transfer from the PVDF matrix to the nanofillers

    Preparation, Properties and Water Dissolution Behavior of Polyethylene Oxide Mats Prepared by Solution Blow Spinning

    Get PDF
    The relationship between processing conditions, structure and morphology are key issues to understanding the final properties of materials. For instance, in the case of polymers to be used as scaffolds in tissue engineering, wound dressings and membranes, morphology tuning is essential to control mechanical and wettability behaviors. In this work, the relationship between the processing conditions of the solution blow spinning process (SBS) used to prepare nonwoven mats of polyethylene oxide (PEO), and the structure and morphology of the resulting materials are studied systematically, to account for the thermal and mechanical behaviors and dissolution in water. After finding the optimal SBS processing conditions (air pressure, feed rate, working distance and polymer concentration), the effect of the solvent composition has been considered. The structure and morphology of the blow spun fibers are studied as well as their thermal, mechanical behaviors and dissolution in water. We demonstrate that the morphology of the fibers (size and porosity) changes with the solvent composition, which is reflected in different thermal and mechanical responses and in the dissolution rates of the materials in water.This work was financially supported by AEI (Ministerio de Ciencia e Innovación of Spain, PID2020-112713RB-C22 and -C21]; the Universidad Carlos III de Madrid, Fondos de Investigación of Fco. Javier González Benito [2012/00130/004] and the strategic Action in Multifunctional Nanocomposite Materials [Code: 2011/00287/003]

    The Recovery, Transformation and Resilience Plan and its macroeconomic impact from a sectoral standpoint

    Get PDF
    Rationale The Recovery, Transformation and Resilience Plan (RTRP), linked to Next Generation EU, details an investment programme that represents a unique opportunity to facilitate the structural transformation of the Spanish economy, on account of both the plan’s envelope (around €69.5 billion or 5.6% of GDP in 2019) and its emphasis on the challenges posed by digitalisation and the green transition. A sectoral classification of how those investments are allocated is therefore interesting in order to quantify their macroeconomic impact, taking into account the interplay between the different sectors of activity. Takeaways •According to the findings, fully absorbing the RTRP funds would have a direct impact on GDP of 1.15% in annual average terms over a five-year horizon, although this figure could rise to 1.75% when considering spillover effects between sectors. •The estimated effects are heterogeneous across sectors; the sectors benefiting the most are those linked to the digitalisation process (information and communication, and professional and technical services) and the construction sector, owing to investment in public infrastructures related to the green transition. •However, rigidities in the reallocation of resources between sectors of activity could limit the macroeconomic effect of the investments envisaged in the RTRP. These factors could reduce the estimated impact from 1.75% to 1.3% of GDP

    Airbrushed Polysulfone (PSF)/Hydroxyapatite (HA) Nanocomposites: Effect of the Presence of Nanoparticles on Mechanical Behavior

    Get PDF
    Nanocomposite films of polysulfone (PSF)—hydroxyapatite (HA) were prepared with a commercial airbrush. Structural, thermal, and mechanical characterization allows obtaining new information to understand the role of the nanofiller–polymer matrix interphase in the final performance of these materials in relation to its possible applications in the restoration of bones. Fourier-transform infrared spectroscopy shows that there are hardly any structural changes in the polymer when adding HA particles. From thermal analysis (differential scanning calorimetry and thermogravimetry), it can be highlighted that the presence of HA does not significantly affect the glass transition temperature of the PSF but decelerates its thermal degradation. All this information points out that any change in the PSF performance because of the addition of HA particles cannot be due to specific interactions between the filler and the polymer. Results obtained from uniaxial tensile tests indicate that the addition of small amounts of HA particles (1% wt) leads to elastic moduli higher than the upper bound predicted by the rule of mixtures suggesting there must be a high contribution of the interphase. A simple model of the nanocomposite is proposed for which three contributions must be considered, particles, interphase and matrix, in such a way that interphases arising from different particles can interact by combining with each other thus leading to a decrease in its global contribution when the amount of particles is high enough. The mechanical behavior can be explained considering a balance between the contribution of the interphase and the number of particles. Finally, a particular mechanism is proposed to explain why in certain nanocomposites relatively high concentrations of nanoparticles may substantially increase the strain to failure.The authors wish to acknowledge financial support from Fondos de Investigación de Fco., Javier González Benito, política de reinversión de costes generales, Universidad Carlos III de Madrid (2012/00130/004), Acción Estratégica en Materiales Compuestos Poliméricos e Interfases, Universidad Carlos III de Madrid (2011/00287/002) and Adquisición de un microscopio electrónico de barrido de emisión de campo y ambiental (FEDER) (2013/00540/001), and project number 2020/00355/001 from CAM (Comunidad Autónoma de Madrid). This work has been supported by Comunidad de Madrid (Spain) multiannual agreement with UC3M (“Excelencia para el Profesorado Universitario”- EPUC3M04) fifth regional research plan 2016–2020
    corecore