On accident causation models, safety training and virtual reality.

Inefficiency in real-time visualization and user interaction in traditional accident causation models (ACMs) necessitates the development of a dynamic ACM that can foster real-time hazard identification, accident prevention and interactive safety training. A virtual reality-based accident causation model (VR-ACM) may serve such a purpose. In this study, we performed a comprehensive literature review on different ACMs and safety training practices. The limitations of the existing models and practices are identified. A VR-ACM model is proposed comprising three modules: VR-based modelling and simulation, accident causation and safety training. Several research issues for VR-ACM are highlighted. An experimental study with 22 crane operators is presented, showing the applicability of the proposed model. The proposed VR-ACM serves as a medium for analysis of potential underlying causes of accidents, the three-dimensional perspective of visual analysis, real-time user interactions and real-time judgement and decision-making.

Training in temporal bone drilling.

Acquiring surgical experience in the operating room is increasingly difficult. Simulation of temporal bone drilling is therefore essential, and more and more widely used. The aim of this review is to clarify the limitations of classical surgical training, and to describe the different types of simulation available for temporal bone drilling. Systematic Medline search used the terms: "temporal bone" and training and surgery; "temporal bone" and training and drilling. Seventy-one of the 467 articles identified were relevant for this review. Various temporal bone simulators have been created to get around the limitations (ethical, financial, cultural, working time) of temporal bone drilling. They can be classified as cadaver, animal, physical or virtual models. The main advantages of physical and virtual prototyping are their ease of access, the possibility of repeating gestures on a standardised model, and the absence of ethical issues. Validation is essential before these simulators can be included in the curriculum, to ensure efficacy and thus improve patient safety in the operating room.

Dynamics analysis and electromagnetic characteristics calculation of permanent magnet 3-degree-of-freedom motor.

This article proposes a conceptual model of a new type permanent magnet 3-degree-of-freedom motor. Its structure consists of an internal rotation module and a peripheral deflection module. It can be driven independently to achieve high-speed rotation and precise tilting of the motor. The 3-degree-of-freedom movement of the motor in space is achieved by the synchronous operation of the rotation and the deflection. In order to explore the loss problem caused by the temperature rise problem in the actual operation of the motor, the eddy current loss and core loss inside the permanent magnet of the motor are analyzed by theoretical formula and finite element method, respectively. Based on the static magnetic field, the gas flux density of two types of rotor permanent magnets in different coordinate systems is analyzed. The motor's rotation and deflection torque characteristics are calculated using the principle of virtual displacement method. Using the auxiliary technology of the virtual prototype, according to the actual situation of the motor, the corresponding motion hinges and driving forms are summarized, and the control strategies of rotation, deflection, and rotation and deflection simultaneously are planned. The trajectory of the motor is described by observing the selected points. For the motor from product design to prototype testing and to the final processing assembly, a solid theoretical foundation is laid for the proposed work.

A Novel, Non-Invasive Approach to Diagnosing Urinary Tract Obstruction Using CFD.

Aims: Urinary tract obstruction is a common clinical problem involving narrowing anywhere along the ureters or urethra. Current diagnostic methods are invasive and costly, and urologists are constantly seeking new, inexpensive, non-invasive measures to diagnose obstruction. The present study investigates diagnostic applications of computational fluid dynamics (CFD) to urinary tract obstruction for the first time. Methods: Various hypothetical models were initially created in Gambit 2.1.6, in which the physics of flow was evaluated based on varying geometries and conditions. These models presented short segments of the tract and possible effects of obstruction. Flow analysis was conducted in Fluent 6.1.22 by comparing contours of velocity, static pressure, dynamic pressure, total pressure, and wall shear stress to results predicted by flow theory. Realistic models of both healthy and obstructed urethras and ureters were then similarly created and simulated. Results: CFD equations accurately predicted the expected flow characteristics through both hypothetical and realistic models. Comparison of modeled urethral outlet velocity to human uroflowmetry data shows that the simulated conditions are almost identical to realistic human flow. Conclusions: The accuracy of the models suggests clinical potential of using CFD with current techniques in human tract analysis, secondary flow effects, disease prevention, and non-invasive diagnosis.