527 research outputs found

    Effect of Low Grade Copper ore on Process Control and Costing at Mosaboni Concentrator

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    The concentrator was designed to produce 22-24% Cu. concentrate from head value of around 1.5-1.3% Cu. Due to change in the method of mining and the lowe-ring of cut-off grade of mined ore, the grade has gone down drastically to 1.12% which has posed process control problems to mantain and even to increase the concentrate grade without sacrificing recovery. The decreased ore grade results in low metal extraction thereby production cost increases

    3D Engineered Peripheral Nerve: Towards A New Era of Patient-Specific Nerve Repair Solutions

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    Reconstruction of peripheral nerve injuries (PNIs) with substance loss remains challenging because of limited treatment solutions and unsatisfactory patient outcomes. Currently, nerve autografting is the first-line management choice for bridging critical-sized nerve defects. The procedure, however, is often complicated by donor site morbidity and paucity of nerve tissue, raising a quest for better alternatives. The application of other treatment surrogates, such as nerve guides remains questionable, and inefficient in irreducible nerve gaps. More importantly, these strategies lack customization for personalized patient therapy, which is a significant drawback of these nerve repair options. This negatively impacts the fascicle-to-fascicle regeneration process, critical to restoring the physiological axonal pathway of the disrupted nerve. Recently, the use of additive manufacturing (AM) technologies has offered major advancements to the bioengineering solutions for PNI therapy. These techniques aim to reinstate the native nerve fascicle pathway using biomimetic approaches, thereby augmenting end-organ innervation. AM-based approaches, such as 3D bioprinting, are capable of biofabricating 3D engineered nerve graft scaffolds in a patient-specific manner with high precision. Moreover, realistic in vitro models of peripheral nerve tissues that represent the physiologically and functionally relevant environment of human organs could also be developed. However, the technology is still nascent and faces major translational hurdles. In this review, we spotlighted the clinical burden of PNIs and most up-to-date treatment to address nerve gaps. Next, a summarized illustration of the nerve ultrastructure that guides research solutions is discussed. This is followed by a contrast of the existing bioengineering strategies used to repair peripheral nerve discontinuities. In addition, we elaborated on the most recent advances in 3D printing (3DP) and biofabrication applications in peripheral nerve modeling and engineering. Finally, the major challenges that limit the evolution of the field along with their possible solutions are also critically analyzed

    A Method for the Design of Compliant Mechanisms With Small-Length Flexural Pivots

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    Compliant or flexible-link mechanisms gain some or all of their motion from the relative flexibility of their joints rather than from rigid-body joints only. Unlike rigid-body mechanisms, energy is not conserved between the input and output ports of compliant mechanisms because of energy storage in the flexible members. This effect and the nonlinearities introduced by large deflections complicate the analysis of such mechanisms. The design of compliant mechanisms in industry is currently accomplished by expensive trial and error methods. This paper introduces a method to aid in the design of a class of compliant mechanisms wherein the flexible sections {flexural pivots) are small in length compared to the relatively rigid sections. The method includes a definition and use of a pseudo-rigid-body model, and the use of a large-deflection finite element type algorithm. An example is used to illustrate the design technique described

    Impact of seam on liquid transmission behaviour of multi-layered ensembles using sweat and water

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    457-463Present study is focussed on the effect of seam on the moisture transmission in liquid form. Behaviour of actual sweat is found to be different from pure water used while evaluating the performance of multilayer clothing systems in seamed and unseamed condition in terms of their in-plane (wetting time) & cross-plane moisture transmission and overall moisture management capacity. Uni-directional seam shows higher wetting time at the inner surface as well as better cross-plane transmittance, and hence better overall moisture management capacity as compared to bi-directional stitched and unseamed fabrics. In all the cases, sweat shows less wetting time than water. Multi-layered ensemble with polyester spacer fabric as middle layer exhibits better overall moisture management properties in comparison to layered ensemble with fleece fabric as middle layer both in seamed and unseamed conditions. Seam type plays a most significant role followed by type of layered ensembles then solution type in affecting the overall moisture management behaviour of seamed ensembles

    Stem‐cell–based therapies to enhance peripheral nerve regeneration

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    Peripheral nerve injury remains a major cause of morbidity in trauma patients. Despite advances in microsurgical techniques and improved understanding of nerve regeneration, obtaining satisfactory outcomes after peripheral nerve injury remains a difficult clinical problem. There is a growing body of evidence in preclinical animal studies demonstrating the supportive role of stem cells in peripheral nerve regeneration after injury. The characteristics of both mesoderm‐derived and ectoderm‐derived stem cell types and their role in peripheral nerve regeneration are discussed, specifically focusing on the presentation of both foundational laboratory studies and translational applications. The current state of clinical translation is presented, with an emphasis on both ethical considerations of using stems cells in humans and current governmental regulatory policies. Current advancements in cell‐based therapies represent a promising future with regard to supporting nerve regeneration and achieving significant functional recovery after debilitating nerve injuries.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154610/1/mus26760.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154610/2/mus26760_am.pd

    Impact of seam on liquid transmission behaviour of multi-layered ensembles using sweat and water

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    Present study is focussed on the effect of seam on the moisture transmission in liquid form. Behaviour of actual sweat is found to be different from pure water used while evaluating the performance of multilayer clothing systems in seamed and unseamed condition in terms of their in-plane (wetting time) & cross-plane moisture transmission and overall moisture management capacity. Uni-directional seam shows higher wetting time at the inner surface as well as better cross-plane transmittance, and hence better overall moisture management capacity as compared to bi-directional stitched and unseamed fabrics. In all the cases, sweat shows less wetting time than water. Multi-layered ensemble with polyester spacer fabric as middle layer exhibits better overall moisture management properties in comparison to layered ensemble with fleece fabric as middle layer both in seamed and unseamed conditions. Seam type plays a most significant role followed by type of layered ensembles then solution type in affecting the overall moisture management behaviour of seamed ensembles

    Impact of varying lactate concentration in sweat on liquid moisture transmission behaviour of layered ensembles 

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    The present study is focussed on the impact of change in the lactate concentration (43 mM and 22 mM) in sweat solution on liquid moisture transmission behaviour through the clothing. The sweat solution with higher concentration of lactate (43 mM) shows delayed wetting at the top surface both in case of individual layer and multi-layer fabric ensembles, i.e. it takes longer time to wet the top surface in spite of the lower contact angle made by it. Significant difference is observed in in-plane transmission behaviour of both the sweat solutions in the case of multi-layered ensembles. In case of multi-layered ensembles, wetting time reduces drastically, even though both the ensembles consist of polyester knit as the inner surface possessing wetting time is 50 s approximately. Sweat solution with higher lactate concentration also shows higher cross-planar transmission rate as compared to in-plane transmission. Uni-directional seamed multi-layered spacer fabric exhibits better overall moisture management coefficient as compared to bi-directional seamed spacer ensembles with sweat solution containing higher lactate concentration. Middle layer also plays a vital role in altering the overall liquid moisture transmission behaviour

    Optimized Current Density Reconstruction from Widefield Quantum Diamond Magnetic Field Maps

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    Quantum Diamond Microscopy using Nitrogen-Vacancy (NV) defects in diamond crystals has enabled the magnetic field imaging of a wide variety of nanoscale current profiles. Intimately linked with the imaging process is the problem of reconstructing the current density, which provides critical insight into the structure under study. This manifests as a non-trivial inverse problem of current reconstruction from noisy data, typically conducted via Fourier-based approaches. Learning algorithms and Bayesian methods have been proposed as novel alternatives for inference-based reconstructions. We study the applicability of Fourier-based and Bayesian methods for reconstructing two-dimensional current density maps from magnetic field images obtained from NV imaging. We discuss extensive numerical simulations to elucidate the performance of the reconstruction algorithms in various parameter regimes, and further validate our analysis via performing reconstructions on experimental data. Finally, we examine parameter regimes that favor specific reconstruction algorithms and provide an empirical approach for selecting regularization in Bayesian methods.Comment: 12 Pages main paper with 7 Figures. 6 pages and 2 figures in supplementary materia
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