803 research outputs found

    The impacts of human resource management practices and pay inequality on workers' job satisfaction

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    In this paper we investigate the relationship between Human Resource Management (HRM) practices and workers' overall job satisfaction and their satisfaction with pay. To investigate these issues we use British data from the 'Changing Employment Relationships, Employment Contracts and the Future of Work Survey' and the 'Workplace Employment Relations Survey'. After controlling for personal, job and firm characteristics, it is shown that several HRM practices raise workers overall job satisfaction and their satisfaction with pay, but these effects are only significant for non-union members. Satisfaction with pay is higher where performance-related pay and seniority-based reward systems are in place. A pay structure that is perceived to be unequal is associated with a substantial reduction in both non-union members' overall job satisfaction and their satisfaction with pay. Although HRM practices can raise worker job satisfaction, if workplace pay inequality widens as a consequence then non-union members may experience reduced job satisfaction.

    BIOLOGICALLY STRUCTURED MATERIALS

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    Biomimetics, biomechanics, and tissue engineering are three multidisciplinary fields that have been contemplated in this research to attain the objective of improving prosthetic implants reliability. Since testing and mathematical methods are closely interlaced, a promising approach seemed to be the combination of in vitro and in vivo experiments with computer simulations (in silico). An innovative biomimetics and biomechanics approach, and a new synthetic structure providing a microenvironment, which is mechanically coherent and nutrient conducive for tissue osteoblast cell cultures used in regenerative medicine, are presented. The novel hybrid ceramic-polymeric nanocomposites are mutually investigated by finite element analysis (FEA) biomimetic modeling, anatomic reconstruction, quantitative-computed-tomography characterization, computer design of tissue scaffold. The starting base materials are a class of innovative highly bioactive hybrid ceramic-polymeric materials set-up by the proponent research group that will be used as a bioactive matrix for the preparation of in situ bio-mineralized techno- structured porous nanocomposites. This study treats biomimetics, biomechanics and tissue engineering as strongly correlated multidisciplinary fields combined to design bone tissue scaffolds. The growth, maintenance, and ossification of bone are fundamental and are regulated by the mechanical cues that are imposed by physical activities: this biomimetic/biomechanical approach will be pursued in designing the experimental procedures for in vitro scaffold mineralization and ossification. Bio-tissue mathematical modeling serves as a central repository to interface design, simulation, and tissue fabrication. Finite element computer analyses will be used to study the role of local tissue mechanics on endochondral ossification patterns, skeletal morphology and mandible thickness distributions using single and multi-phase continuum material representations of clinical cases of patients implanted with the traditional protocols. New protocols will be hypothesized for the use of the new biologically techno-structured hybrid materials

    TRABECULAR PROSTHESES

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    The complex biomechanics and morphology of the femur proximal epiphysis are presented. This specific region in the human femur is characterized by high flexibility compared to that of other primates, since evolved lighter and longer due to the human vertical position and more balanced loading. The nature and fine morphology of the femur head and its structural behavior have been investigated. Isotropic and orthotropic trabecular structures, which are not present in other primates, have been associated with compression and tension areas of the femur head. These isotropic/orthotropic trabecular morphologies and allocations govern the stress and strain distribution in the overall proximal femur region. Use of femur proper biofidel modeling while enabling the explanation of physiological stress distribution elucidates the critical mechanical role of the trabecular bone that should be accounted in the design of a new innovative more "biologic" prosthetic system

    Agile Methodology in Online Learning and How It Can Improve Communication: A Case Study

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    This paper presents a study on using Agile methodologies in the teaching process at the university/college level during the Covid-19 pandemic, online classes. We detail a list of techniques inspired from software engineering Agile methodologies that can be used in online teaching. We also show, by analyzing students grades, that these Agile inspired techniques probably help in the educational process.Comment: Proceedings of the 17th International Conference on Software Technologies, ISBN 978-989-758-588-3, ISSN 2184-2833, pages 542-54

    Some aspects of the human body's hydraulics

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    This paper presents some aspects related to the human body's hydraulics in the desire to make readers aware of how to maintain all the blood vessels of the human body in order to maintain the entire healthy, functional, young, vigorous circulatory system for a while the longest possible. The problem is complex because it has to be viewed from all points of view and not only as an isolated system in the body, having aspects of feedback on the whole physiopathology belonging to the human body. The highly circulating system needs permanent maintenance. Self-maintenance is done through various physiological mechanisms tightly linked to each other, including the lymphatic, digestive, renal, lung, nervous, glandular system
 It is not possible to completely separate the physiology of a system from the other adjacent systems because they all work synergistically, being permanently controlled by the central and peripheral nervous system

    Biomechanically tunable nano-silica/p-hema structural hydrogels for bone scaffolding

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    Innovative tissue engineering biomimetic hydrogels based on hydrophilic polymers have been investigated for their physical and mechanical properties. 5% to 25% by volume loading PHEMA-nanosilica glassy hybrid samples were equilibrated at 37◩C in aqueous physiological isotonic and hypotonic saline solutions (0.15 and 0.05 M NaCl) simulating two limiting possible compositions of physiological extracellular fluids. The glassy and hydrated hybrid materials were characterized by both dynamo-mechanical properties and equilibrium absorptions in the two physiological-like aqueous solutions. The mechanical and morphological modifications occurring in the samples have been described. The 5% volume nanosilica loading hybrid nanocomposite composition showed mechanical characteristics in the dry and hydrated states that were comparable to those of cortical bone and articular cartilage, respectively, and then chosen for further sorption kinetics characterization. Sorption and swelling kinetics were monitored up to equilibrium. Changes in water activities and osmotic pressures in the water-hybrid systems equilibrated at the two limiting solute molarities of the physiological solutions have been related to the observed anomalous sorption modes using the Flory-Huggins interaction parameter approach. The bulk modulus of the dry and glassy PHEMA-5% nanosilica hybrid at 37◩C has been observed to be comparable with the values of the osmotic pressures generated from the sorption of isotonic and hypotonic solutions. The anomalous sorption modes and swelling rates are coherent with the difference between osmotic swelling pressures and hybrid glassy nano-composite bulk modulus: the lower the differences the higher the swelling rate and equilibrium solution uptakes. Bone tissue engineering benefits of the use of tuneable biomimetic scaffold biomaterials that can be “designed” to act as biocompatible and biomechanically active hybrid interfaces are discussed

    Glassy amorphous metal injection molded induced morphological defects

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    Melt rheology in injection molded metastable supercooled liquid metal of Zr44-Ti11-Cu10-Ni10-Be25 alloy may induce selective crystallizations. High mobility Be, Cu and Ni atoms have been observed to differently crystallize in bulk metal glassy supercooled liquids. Here, we analyze the result of morphological microscopic observation conduct on Bulk Metallic Glass (BMG) with composition of a commercial liquid metal alloy (LM001B). The injection molded plate has been supplied by “Liquid Metals Technologies Inc, Ca USA” and manufactured using an Engel injection molding machine operating at 1050-1100°C; the observed sample then has been cut by water jet. FEI Scios Dual-Beam has carried out the microscopic observation. Particularly, through a cross section, we observe the presence of crystalline phases on the short-range order. We investigate the presence of short-range order clusters, their distribution and the effect that they could cause on the alloys’ behaviors and properties

    Biomechanically inspired shape memory effect machines driven by muscle like acting NiTi alloys

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    The research shows a bioinspired approach to be adopted to design of systems based on Shape Memory Alloys (SMAs), a class of Smart Materials that has in common with muscles the capability to react to an impulse (thermal for SMAs) with a contraction. The biomechanically inspired machine that is discussed in the paper refers to the antagonistic muscles pairs, which belongs to the Skeletal Muscles and are normally arranged in opposition so that as one group of muscles contract another group relaxes or lengthens. The study proposes a model, a solution not only to design a specific application, but also to provide an approach to be used for a wide range of adaptive applications (switchable windows, smart shadow systems, parking and urban shelters, etc.), where the shape changes in response to different external stimuli. The use of antagonist pairs mechanism provides a solution for better optimized systems based on SMAs where the main and proven advantages are: Easier and faster change of shape, lower need of energy for system operation, lower cost for SMA training and no problem of overheating

    Velocity-Based LOD Reduction in Virtual Reality: A Psychometric Approach

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    Virtual Reality headsets enable users to explore the environment by performing self-induced movements. The retinal velocity produced by such motion reduces the visual system's ability to resolve fine detail. We measured the impact of self-induced head rotations on the ability to detect quality changes of a realistic 3D model in an immersive virtual reality environment. We varied the Level-of-Detail (LOD) as a function of rotational head velocity with different degrees of severity. Using a psychophysical method, we asked 17 participants to identify which of the two presented intervals contained the higher quality model under two different maximum velocity conditions. After fitting psychometric functions to data relating the percentage of correct responses to the aggressiveness of LOD manipulations, we identified the threshold severity for which participants could reliably (75\%) detect the lower LOD model. Participants accepted an approximately four-fold LOD reduction even in the low maximum velocity condition without a significant impact on perceived quality, which suggests that there is considerable potential for optimisation when users are moving (increased range of perceptual uncertainty). Moreover, LOD could be degraded significantly more in the maximum head velocity condition, suggesting these effects are indeed speed dependent

    PRODUCTION PERFORMANCE OF SOME WHEAT VARIETIES IN THE PEDOCLIMATE CONDITIONS FROM SCDA CARACAL

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    Knowing the particularities of the reaction of the new varieties and hybrids of the crop plants, under different conditions of experimentation is one of the basic activities of the experimental agricultural research and its aim is their judicious choice for cultivation in certain areas. The paper presents the production results obtained from two Romanian varieties of autumn wheat grown under pedoclimatic conditions at SCDA Caracal, under non-irrigation regime, during three years of experimentation. Taking into consideration the variations of the climatic conditions over the years of experimentation, at the same level of fertilization, the productions obtained for the two varieties of wheat recommend their cultivation in the area of the Caracal Plain
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