Factors Associated With the Accuracy of Depth Gauge Measurements

Background: It is important to select appropriate screws in orthopedic surgeries, as excessively long or too short a screw may results failure of the surgeries. This study explored factors that affect the accuracy of measurements in terms of the experience of the surgeons, passage of drilled holes and different depth gauges.Methods: Holes were drilled into fresh porcine femurs with skin in three passages, straight drilling through the metaphysis, straight drilling through the diaphysis, and angled drilling through the diaphysis. Surgeons with different surgical experiences measured the holes with the same depth gauge and using a vernier caliper as gold standard. The length of selected screws, and the time each surgeon spent were recorded. The measurement accuracy was compared based on the experiences of the surgeons and the passage of drilled holes. Further, parameters of depth gauges and 12-mm cortical bone screws from five different manufacturers were measured.Results: A total of 13 surgeons participated in 585 measurements in this study, and each surgeon completed 45 measurements. For the surgeons in the senior, intermediate, and junior groups, the average time spent in measurements was 689, 833, and 785 s with an accuracy of 57.0, 42.2, and 31.5%, respectively. The accuracy and measurement efficiency were significantly different among the groups of surgeons (P < 0.001). The accuracy of measurements was 45.1% for straight metaphyseal drilling, 43.6% for straight diaphyseal drilling, and 33.3% for angled diaphyseal drilling (P = 0.036). Parameters of depth gauges and screws varied among different manufacturers.Conclusion: Both observer factor and objective factors could affect the accuracy of depth gauge measurement. Increased surgeon's experience was associated with improvements in the accuracy rate and measurement efficiency of drilled holes based on the depth gauge. The accuracy rate varied with hole passages, being the lowest for angled drilled holes.

Development of Capacitive Rain Gauge for Marine Environment

At present, the methods and instruments for measuring the precipitation on land may not effectively work in the offshore corrosion environment which is characterized by salt and humid. The research look at investigating the reliable and precision approach of measuring rainfall and a capacitive rain gauge for the marine environment is developed. Firstly, according to the working principle and performance requirements of the capacitive rain gauge, the modular mechanical structure and capacitance voltage conversion circuit of the rain gauge are designed, and the calibration and stability experiments of the prototype are tested to evaluate the measurement error and exam the accuracy of the rain gauge measurement results changing over time. Then, environmental adaptability experiment is carried out on the capacitive rain gauge to explore its performance in the environment of temperature and humidity changes as well as salt spray. Finally, the feasibility of the rain gauge used in the marine environment is verified by the sea test of the prototype. The measurement error of the developed capacitive rain gauge is less than 1 mm, which provides a realization method for the measurement of precipitation in the marine environment.

Application of laser scanning technology for structure gauge measurement

One of the basic conditions guaranteeing safe and collision-free operation of rail vehicles is maintaining the structure gauge. Verification of the location of rail infrastructure components is carried out using various measurement techniques. This article describes the accuracy of the gauge measurement with the use of a scanning tachymeter. Tachymetric measurements and laser scanning technology were used in the experimental study of the tram loop area. The analysis covered the possibility of using a point cloud to determine geometrical relationships among the track, traction poles and the overhead line. The quality of the laser scanning data in terms of the measurement frequency, the laser beam angle of incidence per object and the average reflection intensity was examined. Performed verification was based on the data from tachymetric measurements. In the tested area, the track consists of straight sections and several circular arcs of small radii and variable curvature. The specific geometry of the track required calculation of the gauge extension parameters depending on the curve radius. In addition, a horizontal track alignment design was prepared. The designed location of the track and extended dimensions of the structure gauge were used to verify the correct spatial position of the current track in relation to the infrastructure elements.