3,785 research outputs found
Double standards in healthcare innovations: the case of mosquito net mesh for hernia repair
With over two decades of evidence available including from randomised clinical trials, we explore whether the use of low-cost mosquito net mesh for inguinal hernia repair, common practice only in low-income and middle-income countries, represents a double standard in surgical care. We explore the clinical evidence, biomechanical properties and sterilisation requirements for mosquito net mesh for hernia repair and discuss the rationale for its use routinely in all settings, including in high-income settings. Considering that mosquito net mesh is as effective and safe as commercial mesh, and also with features that more closely resemble normal abdominal wall tissue, there is a strong case for its use in all settings, not just low-income and middle-income countries. In the healthcare sector specifically, either innovations should be acceptable for all contexts, or none at all. If such a double standard exists and worse, persists, it raises serious questions about the ethics of promoting healthcare innovations in some but not all contexts in terms of risks to health outcomes, equitable access, and barriers to learning
Plasma splashing from Al and Cu materials induced by and Nd : YAG pulsed laser
Plasma splashing from Al and Cu target materials and the growth of thin films on Cu and Al, respectively, has been studied using a Q-switched Nd:YAG laser with a 1064-nm, 80-mJ, 8-ns pulse width as the source of ablation. The target kept rotating and the substrate, Cu for Al and vice versa, was placed at an angle of 15° with respect to the beam axis. During the laser-matter interaction, the targets absorbed thermal energy within the thermal region depth of 4.7 (1.1) nm, yielding an ablated skin depth of 6.7 (4.2) nm. The surface morphology of the exposed targets was studied by analyzing SEM micrographs obtained using a ZEISS SUPRA 35 VP. The obtained results are explained on the basis of different sputtering/ablation mechanisms. Comparatively severe damage forming a bigger crater is seen on the Al target surface in contrast to the crater on the Cu surface. This observation is correlated with the blustering effect and/or debris formation. Energy dispersive spectroscopy (EDX) of the substrates yielded the deposition of micrometric grain-size particle
The exact evaluation of the corner-to-corner resistance of an M x N resistor network: Asymptotic expansion
We study the corner-to-corner resistance of an M x N resistor network with
resistors r and s in the two spatial directions, and obtain an asymptotic
expansion of its exact expression for large M and N. For M = N, r = s =1, our
result is
R_{NxN} = (4/pi) log N + 0.077318 + 0.266070/N^2 - 0.534779/N^4 + O(1/N^6).Comment: 12 pages, re-arranged section
Haptically enabled interactivity and immersive virtual assembly
Virtual training systems are attracting paramount attention from the manufacturing industries due to their potential advantages over the conventional training practices such as general assembly. Within this virtual training realm for general assembly, a haptically enabled interactive and immersive virtual reality (HIVEx) system is presented. The idea is to imitate real assembly training scenarios by providing comprehensive user interaction as well as by enforcing physical constraints within the virtual environment through the use of haptics technology. The developed system employs a modular system approach providing flexibility of reconfiguration and scalability as well as better utilization of the current multi-core computer architecture. The user interacts with the system using haptics device and data glove while fully immersed into the virtual environment with depth perception. An evaluation module, incorporated into the system, automatically logs and evaluates the information through the simulation providing user performance and improvements over time. A ruggedized portable version of the system is also developed and presented with full system capabilities allowing easy relocation with different factory environments. A number of training scenarios has been developed with varying degree of complexity to exploit the potential of the presented system. The presented system can be employed for teaching and training of existing assembly processes as well as the design of new optimised assembly operations. Furthermore, the presented system can assist in optimizing existing practices by evaluating the effectiveness and the level of knowledge transfer involved in the process. Within the aforementioned conceptual. framework, a working prototype is developed.<br /
Haptically enable interactive virtual assembly training system development and evaluation
Virtual training systems are attracting paramount attention from the manufacturing industries due to their potential advantages over the conventional training practices. Significant cost savings can be realized due to the shorter times for the development of different training-scenarios as well as reuse of existing designed engineering (math) models. In addition, use of computer based virtual reality (VR) training systems can shorten the time span from computer aided product design to commercial production due to non-reliance on the hardware parts for training. Within the aforementioned conceptual framework, a haptically enabled interactive and immersive virtual reality (HIVEx) system is presented. Unlike existing VR systems, the presented idea tries to imitate real physical training scenarios by providing comprehensive user interaction, constrained within the physical limitations of the real world. These physical constrains are imposed by the haptics devices in the virtual environment. As a result, in contrast to the existing VR systems that are capable of providing knowledge generally about assembly sequences only, the proposed system helps in cognitive learning and procedural skill development as well, due to its high physically interactive nature.<br /
Mini workshop - Real World Engineering Projects: Discovery-based curriculum modules for first-year students
This mini workshop is organized to provide an interactive forum for the introduction a set of six new curriculum modules developed under IEEE's Real World Engineering Projects (RWEP) program. The modules, which are representative of a larger collection of curriculum modules available to the public via an open-access RWEP web portal, are designed for use in the first-year engineering and computer science classroom, and are hands-on, team-based projects that emphasize the societal impact of the work that engineers do. After a brief introduction to the RWEP program and the six showcased curriculum modules, the authors of the modules will present their ideas and demonstrate the laboratory activities associated with their modules in interactive, informal simultaneous sessions. © 2010 IEEE.published_or_final_versionThe 40th ASEE/IEEE Frontiers in Education Conference (FIE) 2010, Arlington, VA., 27-30 October 2010. In Proceedings of 40th FIE, 2010, p. T2A1-T2A
Mini workshop - Real World Engineering Projects: Discovery-based curriculum modules for first-year students
This mini workshop is organized to provide an interactive forum for the introduction a set of six new curriculum modules developed under IEEE's Real World Engineering Projects (RWEP) program. The modules, which are representative of a larger collection of curriculum modules available to the public via an open-access RWEP web portal, are designed for use in the first-year engineering and computer science classroom, and are hands-on, team-based projects that emphasize the societal impact of the work that engineers do. After a brief introduction to the RWEP program and the six showcased curriculum modules, the authors of the modules will present their ideas and demonstrate the laboratory activities associated with their modules in interactive, informal simultaneous sessions. © 2010 IEEE.published_or_final_versionThe 40th ASEE/IEEE Frontiers in Education Conference (FIE) 2010, Arlington, VA., 27-30 October 2010. In Proceedings of 40th FIE, 2010, p. T2A1-T2A
Slip and hall current effects on Jeffrey fluid suspension flow in a peristaltic hydromagnetic blood micropump
The magnetic properties of blood allow it to be manipulated with an electromagnetic field. Electromagnetic blood flow pumps are a robust technology which provide more elegant and sustainable performance compared with conventional medical pumps. Blood is a complex multi-phase suspension with non-Newtonian characteristics which are significant in micro-scale transport. Motivated by such applications, in the present article a mathematical model is developed for magnetohydrodynamic (MHD) pumping of blood in a deformable channel with peristaltic waves. A Jeffery’s viscoelastic formulation is employed for the rheology of blood. A twophase fluid-particle (“dusty”) model is utilized to better simulate suspension characteristics (plasma and erythrocytes). Hall current and wall slip effects are incorporated to achieve more realistic representation of actual systems. A two-dimensional asymmetric channel with dissimilar peristaltic wave trains propagating along the walls is considered. The governing conservation equations for mass, fluid and particle momentum are formulated with appropriate boundary conditions. The model is simplified using of long wavelength and creeping flow approximations. The model is also transformed from the fixed frame to the wave frame and rendered non-dimensional. Analytical solutions are derived. The resulting boundary value problem is solved analytically and exact expressions are derived for the fluid velocity, particulate velocity, fluid/particle fluid and particulate volumetric flow rates, axial pressure gradient, pressure rise and skin friction distributions are evaluated in detail. Increasing Hall current parameter reduces bolus growth in the channel, particle phase velocity and pressure difference in the augmented pumping region whereas it increases fluid phase velocity, axial pressure gradient and pressure difference in the pumping region. Increasing the hydrodynamic slip parameter accelerates both particulate and fluid phase flow at and close to the channel walls, enhances wall skin friction, boosts pressure difference in the augmented pumping region and increases bolus magnitudes. Increasing viscoelastic parameter (stress relaxation time to retardation time ratio) decelerates the fluid phase flow, accelerates the particle phase flow, decreases axial pressure gradient, elevates pressure difference in the augmented pumping region and reduces pressure difference in the pumping region. Increasing drag particulate suspension parameter decelerates the particle phase velocity, accelerates the fluid phase velocity, strongly elevates axial pressure gradient and reduces pressure difference (across one wavelength) in the augmented pumping region. Increasing particulate volume fraction density enhances bolus magnitudes in both the upper and lower zones of the channel and elevates pressure rise in the augmented pumping region
- …