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A Just-in-Time Video Primer on Pneumothorax Pathophysiology and Early Management
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Removal of an Impaled Intraocular Hair Comb Following Self-inflicted Trauma
Ocular trauma is one of the most common and vision-threatening ophthalmic presentations with a wide spectrum of complications, such as bleeding, infection, vision loss, and enucleation. A 64-year-old-male presented to the emergency department (ED) with a self-inflicted orbital penetrating injury with a hair comb. Computed tomography showed the comb traversed the medial orbit inferior to the medial rectus but did not damage the optic nerve; there were no globe or orbital wall fractures. His ocular exam was significant for a right eye afferent pupillary defect and decreased visual acuity 20/800, consistent with optic neuropathy. Primary concerns were stabilizing and removing the foreign body without causing further damage in the setting of an uncooperative patient. The comb was removed with the aid of local and systemic analgesia using gentle traction and normal saline irrigation. The patient was admitted for systemic and topical antibiotics and showed improvement in visual acuity and resolution of his optic neuropathy. This case illustrates the importance of rapid ED assessment and management of complex penetrating ocular trauma. Examination should specifically look for signs of globe rupture and optic nerve injury. Expedited foreign body removal should be managed together with an ophthalmologist with procedural sedation and broad-spectrum antibiotics to avoid further visual and infectious complications
Thermoelectric effect in an Aharonov-Bohm ring with an embedded quantum dot
Thermoelectric effect is studied in an Aharonov-Bohm interferometer with an embedded quantum dot (QD) in the Coulomb blockade regime. The electrical conductance, electron thermal conductance, thermopower, and thermoelectric figure-of-merit are calculated by using the Keldysh Green's function method. It is found that the figure-of-merit ZT of the QD ring may be quite high due to the Fano effect originated from the quantum interference effect. Moreover, the thermoelectric efficiency is sensitive to the magnitude of the dot-lead and inter-lead coupling strengthes. The effect of intradot Coulomb repulsion on ZT is significant in the weak-coupling regime, and then large ZT values can be obtained at rather high temperature
Vibration modal shapes and strain measurement of the main shaft assembly of a friction hoist
In order to evaluate the reliability of the main shaft unit of a friction hoisting system, strain measurement is a significant method. In this paper, a test rig of a friction hoisting system was built, which could applied periodically changing load on its main shaft unit; The mechanical analysis under the test load was conducted and the boundary limits were obtained; A three dimensional model of the main shaft unit was built in Pro-E and its finite element analysis was performed in ANSYS; With the analytical result, measuring points for strain rosettes were initially selected; Vibration modal shapes of the main shaft unit were analyzed, based on which Modal Assurance Criterion (MAC) was utilized in the Particle Swarm Optimization (PSO) algorithm to make the final decision of the number and positions of the measuring points; A wireless measurement system was developed to acquire strain signals from the optimized measuring positions; The test result verified the efficiency of the methods employed in this paper and revealed how strain of the main shaft unit changes during running process
Life Cycle Integration of Building Information Modeling in Infrastructure Projects
Building Information Modeling (BIM) can provide solutions to many challenges of asset management, such as missing data, incompatible software, and an unclear business process. However, current implementation of BIM in infrastructure projects has only considers limited factors, such as technology application and digital information delivery, while issues of system compatibility and information needs are still missing. Different aspects of a business are interdependent and an incompatible development of various factors might result in different levels of BIM implementation or even project failure. Comprehensive research is needed to explore the key factors and challenges of BIM implementation in infrastructure projects. This study conducted interviews and surveys with key stakeholders of infrastructure projects to explore the challenges and potential solutions of BIM implementation. Interviews were conducted with 37 professionals and surveys were conducted with 102 professional stakeholders, including owners, designers, contractors, and software vendors. Four main factors, challenges, and potential solutions were identified from content analysis of the interviews and further validated by the surveys. These factors include process factor (when), technology factor (how), people factor (who), and information factor (what). Corresponding solutions are proposed to refine the current workflow and practices
Life Cycle Integration of Building Information Modeling in Infrastructure Projects
Building Information Modeling (BIM) can provide solutions to many challenges of asset management, such as missing data, incompatible software, and an unclear business process. However, current implementation of BIM in infrastructure projects has only considers limited factors, such as technology application and digital information delivery, while issues of system compatibility and information needs are still missing. Different aspects of a business are interdependent and an incompatible development of various factors might result in different levels of BIM implementation or even project failure. Comprehensive research is needed to explore the key factors and challenges of BIM implementation in infrastructure projects. This study conducted interviews and surveys with key stakeholders of infrastructure projects to explore the challenges and potential solutions of BIM implementation. Interviews were conducted with 37 professionals and surveys were conducted with 102 professional stakeholders, including owners, designers, contractors, and software vendors. Four main factors, challenges, and potential solutions were identified from content analysis of the interviews and further validated by the surveys. These factors include process factor (when), technology factor (how), people factor (who), and information factor (what). Corresponding solutions are proposed to refine the current workflow and practices
A benchmark test problem toolkit for multi-objective path optimization
Due to the complexity of multi-objective optimization problems (MOOPs) in general, it is crucial to test MOOP methods on some benchmark test problems. Many benchmark test problem toolkits have been developed for continuous parameter/numerical optimization, but fewer toolkits reported for discrete combinational optimization. This paper reports a benchmark test problem toolkit especially for multi-objective path optimization problem (MOPOP), which is a typical category of discrete combinational optimization. With the reported toolkit, the complete Pareto front of a generated test problem of MOPOP can be deduced and found out manually, and the problem scale and complexity are controllable and adjustable. Many methods for discrete combinational MOOPs often only output a partial or approximated Pareto front. With the reported benchmark test problem toolkit for MOPOP, we can now precisely tell how many true Pareto points are missed by a partial Pareto front, or how large the gap is between an approximated Pareto front and the complete one
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