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Modelling commercial vehicle handling and rolling stability
YesThis paper presents a multi-degrees-of-freedom non-linear multibody dynamic
model of a three-axle heavy commercial vehicle tractor unit, comprising a subchassis, front
and rear leaf spring suspensions, steering system, and ten wheels/tyres, with a semi-trailer
comprising two axles and eight wheels/tyres. The investigation is mainly concerned with the
rollover stability of the articulated vehicle. The models incorporate all sources of compliance,
stiffness, and damping, all with non-linear characteristics, and are constructed and simulated
using automatic dynamic analysis of mechanical systems formulation. A constant radius turn
test and a single lane change test (according to the ISO Standard) are simulated. The constant
radius turn test shows the understeer behaviour of the vehicle, and the single lane change
manoeuvre was conducted to show the transient behaviour of the vehicle. Non-stable roll
and yaw behaviour of the vehicle is predicted at test speeds .90 km/h. Rollover stability of
the vehicle is also investigated using a constant radius turn test with increasing speed.
The articulated laden vehicle model predicted increased understeer behaviour, due to higher
load acting on the wheels of the middle and rear axles of the tractor and the influence of the
semi-trailer, as shown by the reduced yaw rate and the steering angle variation during the constant
radius turn. The rollover test predicted a critical lateral acceleration value where complete
rollover occurs. Unstable behaviour of the articulated vehicle is also predicted in the single lane
change manoeuvre
Teaching percutaneous renal biopsy using unfixed human cadavers
Background:
Percutaneous renal biopsy (PRB) is an important diagnostic procedure. Despite advances in its safety profile there remains a small but significant risk of bleeding complications. Traditionally, operators train to perform PRB through tutor instruction and directly supervised PRB attempts on real patients. We describe an approach to teaching operators to perform PRB using cadaveric simulation.
Methods:
We devised a full day course hosted in the Clinical Anatomy Skills Centre, with places for nine candidates. Course faculty consisted of two Consultant Nephrologists, two Nephrology trainees experienced in PRB, and one Radiologist.
Classroom instruction included discussion of PRB indications, risk minimisation, and management of complications. Two faculty members acted as models for the demonstration of kidney localisation using real-time ultrasound scanning. PRB was demonstrated using a cadaveric model, and candidates then practised PRB using each cadaver model.
Results:
Written candidate feedback was universally positive. Faculty considered the cadaveric model a realistic representation of live patients, while the use of multiple cadavers introduced anatomical variation.
Conclusions:
Our model facilitates safe simulation of a high risk procedure. This might reduce serious harm associated with PRB and improve patient safety, benefiting trainee operators and patients alike
Networked Drones for Industrial Emergency Events
Uncontrolled emissions of gases from industrial accidents and disasters
result in huge loss of life and property. Such extreme events require a quick
and reliable survey of the site for effective rescue strategy planning. To
achieve these goals, a network of unmanned aerial vehicles can be deployed that
survey the affected region and identify safe and danger zones. Although single
UAV-based systems for gas sensing applications are well-studied in literature,
research on the deployment of a UAV network for such applications, which is
more robust and fault tolerant, is still in infancy. The objective of this
project is to design a system that can be deployed in emergency situations to
provide a quick survey and identification of safe and dangerous zones in a
given region that contains a toxic plume without making any assumptions about
plume location. We focus on an end-to-end solution and formulate a two-phase
strategy that can not only guarantee detection/acquisition of plume but also
its characterization with high spatial resolution. To guarantee coverage of the
region with a certain spatial resolution, we set up a vehicle routing problem.
To overcome the limitations imposed by limited range of sensors and drone
resources, we estimate the concentration map by using Gaussian kernel
extrapolation. Finally, we evaluate the suggested framework in simulations. Our
results suggest that this two-phase strategy not only gives better error
performance but is also more efficient in terms of mission time. Moreover, the
comparison between 2-phase random search and 2-phase uniform coverage suggest
that the latter is better for single drone systems whereas for multiple drones
the former gives reasonable performance at low computational cost
Pengaruh Strategi Pemasaran terhadap Penjualan Batubara pada PT. Cahaya Mantingan Nusantara Jakarta
The research aims is to collect a complete and accurate data and information concerning about the impact of marketing strategy. This study conducts an analysis to examine and analyze the execution of marketing strategy and sales and also to analyze how big the impact of marketing strategy determine the sales of coal in PT Cahaya Mantingan Nusantara Jakarta, in order to anticipate an intense competition. Correlation analysis concludes a strong and significant correlation between sales and marketing strategy. The determination coefficient shows that 52,25 percent of sales determined by marketing strategy
The Influence of the Upper Extremities Movement on Take-off in Vertical Jump
The positive influence of the upper extremities swing on the effect of take-off in jumping is well known. Such movement is used in vertical jump, long jump, high jump and others. This effect causes increase of the ground reaction force produced by each segment (Luhtanen and Komi, 1978) and in addition the upper extremities swing has also a coordinative meaning, for example while double overarm movement at running is to be change into parallel movement at take off (high jump), There are also such situations like in basketball and volleyball (Wielki and Dangre, 1983; Wilkerson, 1983) in which the desired arms swing is limited by the other task which has to be performed like blocking or passing the ball.
Loss in the height of the vertical jump -while the arms swing is not executed -and diminishing ground reaction force at take-off and the possible changes in biomechanical variables during take-off, are the object of this experiment
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