Implementation of Fiber Element Model for Non-Linear Analysis

RC frames undergo inelastic deformations in the event of an extreme earthquake. Nonlinear modelling of the concrete sections is very much necessary for the simulation of realistic behaviour of RC frames in earthquake loading. Concentrated/lumped plasticity and distributed plasticity are the two different approaches for nonlinear modelling of RC elements available in literature. The main objective of the present study is to implement a displacement based fiber element (stiffness) for nonlinear analysis of RC Sections. The present study focused on the element formulation of both stiffness and flexibility based fiber models, direct integration and numerical integration and incorporation of popular confinement models for stress-strain relationship for concrete. The present study is extended to a probabilistic analysis using the implemented model. It is found that fiber elements are appropriate tool for incorporating nonlinearity in the RC sections

Minimally Invasive Mitral Valve Surgery III: Training and Robotic-Assisted Approaches.

Minimally invasive mitral valve operations are increasingly common in the United States, but robotic-assisted approaches have not been widely adopted for a variety of reasons. This expert opinion reviews the state of the art and defines best practices, training, and techniques for developing a successful robotics program

Minimally Invasive Mitral Valve Surgery I: Patient Selection, Evaluation, and Planning.

Widespread adoption of minimally invasive mitral valve repair and replacement may be fostered by practice consensus and standardization. This expert opinion, first of a 3-part series, outlines current best practices in patient evaluation and selection for minimally invasive mitral valve procedures, and discusses preoperative planning for cannulation and myocardial protection

Minimally Invasive Mitral Valve Surgery II: Surgical Technique and Postoperative Management.

Techniques for minimally invasive mitral valve repair and replacement continue to evolve. This expert opinion, the second of a 3-part series, outlines current best practices for nonrobotic, minimally invasive mitral valve procedures, and for postoperative care after minimally invasive mitral valve surgery

Internet of Things Based Real-Time Monitoring System for Early Age Properties of Concrete

Automation in the construction industry is indispensable to significantly improve productivity, quality, economy, safety, flexibility, and accuracy. The possibilities of recently introduced Internet of Things (IoT) based systems are promising to attain a higher level of automation in the construction industry. Real-time monitoring of various parameters of concrete using IoT technology can leverage the process of automation in the construction industry. The research presented in this thesis poposes a novel, cost-effective,and easily deployable IoT-enabled automation system for the real-time monitoring of early-age concrete properties. Some of the most important properties include early age concrete compressive strength and plastic shrinkage. The estimation of the early-age compressive strength of concrete is crucial for quality control in the construction industry. The first part of the thesis proposes an innovative and cost-effective IoT-enabled system for the real time monitoring of early-age concrete strength using the well-established maturity method. The proposed system consists of temperature sensors and Wi-Fi micro-controllers which are connected to a cloud-based platform. Five selected concrete mixes are used to demonstrate the proposed system. The maturity relationships for the selected mixes are developed in the laboratory as per the relevant standards. The early-age compressive strengths of the selected concrete mixes predicted by the proposed system are found to match well with the actual compressive strengths obtained from the break test. The propo ed system is found to be effective in the automation of the maturity method that can trigger the implementation of user-friendly internet/mobile applications. Timely removal of formwork is one of the crucial aspects of construction management that directly influences the safety and quality of the structure as well as the economy of the project. Code recommendations in this regard are not widely practiced because of the difficulties in their implementations. Also, such code recommendations are not robust for all the possible construction conditions. The next part of this thesis demonstrates the application of an IoT-enabled system that notifies the minimum striking time of vertical formwork based on a specified target compressive strength.The implementation of the proposed system is demonstrated on three concrete columns. The proposed system is found to be suitable for any construction condition and can be easily implemented a tthe site.The hot and dry condition often induces plastic shrinkage cracks on concrete slabs and pavements. Such cracks are a concern for the concrete construction industry,as it affects the quality and long-term performance of the concrete structure. Existing approaches to monitoring plastic shrinkage at the site are time-consuming, labour-intensive, and expensive. As a result, these approaches are not attractive to the construction industry and are not generally practiced at the site. The next part of this thesis proposes a novel, costeffective, and easily deployable IoT-enabled system to monitor plastic shrinkage in realtime. Two alternative systems are proposed, one of which monitors the evaporation rate following the recommendation of the codes and standards. However, existing approac es have not considered the status of surface bleed water despite its essential role in monitorin plastic shrinkage. Therefore, the other alternative system is proposed based on the availability of the surface bleed water sheen. The effectiveness of the proposed system is validated by laboratory experiments on three sets of concrete specimens. The last part of the thesis attempts to incorpo ate Long Range (LoRa) technology into the IoT applications for the construction industry in order to take advantage of its large transmission range. This emerging technology is being used in many civil engineering applications such as water quality control, equipment tracking, etc., and the use of this technology is likely to multiply in the coming years. However, the energy efficiency and environmental impact assessment of such LoRa-based systems have not been addressed in the published literature so far. This thesis, therefore, explore the effect of transmission parameters on power consumption and proposes a scheme for controlling transmission parameters to improve the energy efficiency of LoRa end nodes. The effectiveness of the proposed scheme is demonstrated through a case study on a real-time monitoring system which is crucial for quality control and construction management

Expert consensus document on the treatment of descending thoracic aortic disease using endovascular stent-grafts.

Between 43,000 and 47,000 people die annually in the United States from diseases of the aorta and its branches and continues to increase. For the thoracic aorta, these diseases are increasingly treated by stent-grafting. No prospective randomized study exists comparing stent-grafting and open surgical treatment, including for disease subgroups. Currently, one stent-graft device is approved by the Food and Drug Administration for descending thoracic aortic aneurysms although two new devices are expected to obtain FDA approval in 2008. Stent-graft devices are used off label or under physician Investigational Device Exemption studies for other indications such as traumatic rupture of the aorta and aortic dissection. Early first-generation devices suffered from problems such as stroke with insertion, ascending aortic dissection or aortic penetration from struts, vascular injury, graft collapse, endovascular leaks, graft material failure, continued aneurysm expansion or rupture, and migration or kinking; however, the newer iterations coming to market have been considerably improved. Although the devices have been tested in pulse duplicators out to 10 years, long-term durability is not known, particularly in young patients. The long-term consequences of repeated computed tomography scans for checking device integrity and positioning on the risk of irradiation-induced cancer remains of concern in young patients. This document (1) reviews the natural history of aortic disease, indications for repair, outcomes after conventional open surgery, currently available devices, and insights from outcomes of randomized studies using stent-grafts for abdominal aortic aneurysm surgery, the latter having been treated for a longer time by stent-grafts; and (2) offers suggestions for treatment

Minimally Invasive Mitral Valve Surgery III: Training and Robotic-Assisted Approaches

Minimally invasive mitral valve operations are increasingly common in the United States, but robotic-assisted approaches have not been widely adopted for a variety of reasons. This expert opinion reviews the state of the art and defines best practices, training, and techniques for developing a successful robotics program