40 research outputs found

    Smart materials: strain sensing and stress determination by means of nanotube sensing systems, composites, and devices

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    The present invention is directed toward devices comprising carbon nanotubes that are capable of detecting displacement, impact, stress, and/or strain in materials, methods of making such devices, methods for sensing/detecting/monitoring displacement, impact, stress, and/or strain via carbon nanotubes, and various applications for such methods and devices. The devices and methods of the present invention all rely on mechanically-induced electronic perturbations within the carbon nanotubes to detect and quantify such stress/strain. Such detection and quantification can rely on techniques which include, but are not limited to, electrical conductivity/conductance and/or resistivity/resistance detection/measurements, thermal conductivity detection/measurements, electroluminescence detection/measurements, photoluminescence detection/measurements, and combinations thereof. All such techniques rely on an understanding of how such properties change in response to mechanical stress and/or strain

    Tracking of Stiffness Variation in Structural Members Using Input Error Function Observers

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    This study evaluates input error function observers for tracking of stiffness variation in real-time. The input error function is an Analytical Redundancy (AR)-based diagnosis method and necessitates a mathematical model of the system and system identification techniques. In practice, mathematical models used during numerical simulations differ from the actual status of the structure, and thus, accurate mathematical models are rarely available for reference. Noise is an unwanted signal in the input–output measurements but unavoidable in real-world applications (as in long span bridge trusses) and hard to imitate during numerical simulations. Simulation data from the truss system clearly indicates the effectiveness of the proposed structural damage detection method for estimating the severity of the damage. Optimization of the input error function can further automate the stiffness estimation in structural members and address critical aspects such as system uncertainties and the presence of noise in input–output measurements. Stiffness tracking in one of the planar truss members indicates the potential of optimization of the input error function for online structural health monitoring and implementing condition-based maintenance

    Tracking of Stiffness Variation in Structural Members Using Input Error Function Observers

    Full text link
    This study evaluates input error function observers for tracking of stiffness variation in real-time. The input error function is an Analytical Redundancy (AR)-based diagnosis method and necessitates a mathematical model of the system and system identification techniques. In practice, mathematical models used during numerical simulations differ from the actual status of the structure, and thus, accurate mathematical models are rarely available for reference. Noise is an unwanted signal in the input–output measurements but unavoidable in real-world applications (as in long span bridge trusses) and hard to imitate during numerical simulations. Simulation data from the truss system clearly indicates the effectiveness of the proposed structural damage detection method for estimating the severity of the damage. Optimization of the input error function can further automate the stiffness estimation in structural members and address critical aspects such as system uncertainties and the presence of noise in input–output measurements. Stiffness tracking in one of the planar truss members indicates the potential of optimization of the input error function for online structural health monitoring and implementing condition-based maintenance

    An observational study of incidence, risk factors & outcome of systemic inflammatory response & organ dysfunction following major trauma

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    Background & objectives: Trauma is known to lead to systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS), which is often a cause of late deaths after injury. SIRS and MODS have been objectively measured using scoring systems. This prospective observational study was carried out in a tertiary care hospital in India to evaluate SIRS and MODS following trauma in terms of their incidence, the associated risk factors and the effect on the outcome. Methods: All adult patients with major life- and limb-threatening trauma were included. Patients who died within 24 h, those with severe head injury, known comorbidity, immunocompromised state, on immunosuppressants or pregnancy were excluded. SIRS and MODS scores were recorded after initial management (baseline score), on days 3 and 6 of admission. SIRS was defined as SIRS score of ≥2 and MODS was defined as MODS score of ≥1. Results: Two hundred patients were enrolled. SIRS was noted in 156 patients (78%). MODS was noted in 145 (72.5%) patients. Overall mortality was 39 (19.5%). Both SIRS and MODS scores were significantly associated with age >60 yr, blunt injury, (lower) revised trauma score hypotension on admission and (higher) injury severity score, but not with gender, pre-hospital time or operative treatment. Interpretation & conclusions: Both SIRS and MODS scores were associated with longer Intensive Care Unit (ICU) stay, more ICU interventions and higher mortality. Incidence of MODS was significantly higher in patients with SIRS. Both scores showed rising trend with time in non-survivors and a decreasing trend in survivors. The serial assessment of scores can help prognosticate outcome and also allocate appropriate critical care resources to patients with rising scores

    Laparotomy for blunt abdominal trauma-some uncommon indications

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    Trauma laparotomy after blunt abdominal trauma is conventionally indicated for patients with features of hemodynamic instability and peritonitis to achieve control of hemorrhage and control of spillage. In addition, surgery is clearly indicated for the repair of posttraumatic diaphragmatic injury with herniation. Some other indications for laparotomy have been presented and discussed. Five patients with blunt abdominal injury who underwent laparotomy for nonroutine indications have been presented. These patients were hemodynamically stable and had no overt signs of peritonitis. Three patients had solid organ (spleen, kidney) infarction due to posttraumatic occlusion of the blood supply. One patient had mesenteric tear with internal herniation of bowel loops causing intestinal obstruction. One patient underwent surgery for traumatic abdominal wall hernia. In addition to standard indications for surgery in blunt abdominal trauma, laparotomy may be needed for vascular thrombosis of end arteries supplying solid organs, internal or external herniation through a mesenteric tear or anterior abdominal wall musculature, respectively

    Case Report- Infantile congenital cutis laxa with multiple hernias and ventricular septal defect

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    Cutis laxa is a rare disorder characterized by degenerative changes in elastic fibres. Congenital cutis laxa is more common than acquired cutis laxa. The recessively inherited form is severe and more frequent. Cutis laxa affects all races and both the sexes equally. We report the first ever case of cutis laxa associated with multiple hernias and cardiac anomaly in an infant

    Infantile congenital cutis laxa with multiple hernias and ventricular septal defect

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    Cutis laxa is a rare disorder characterized by degenerative changes in elastic fibres. Congenital cutis laxa is more common than acquired cutis laxa. The recessively inherited form is severe and more frequent. Cutis laxa affects all races and both the sexes equally. We report the first ever case of cutis laxa associated with multiple hernias and cardiac anomaly in an infant
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