Type B Uncertainty Analysis of Gravity-Based Determinations of Triaxial-Accelerometer Properties by Simulation of Measurement Errors

We simulated the effects of gimbal-alignment errors and rotational step-size errors on measurements of the sensitivity matrix and intrinsic properties of a triaxial accelerometer. We restricted the study to measurements carried out on a two-axis calibration system using a previously described measurement and analysis protocol. As well as imperfections in the calibration system, we simulated imperfect orthogonality of the accelerometer axes and non-identical sensitivity of the individual accelerometers in an otherwise perfect triaxial accelerometer, but we left characterization of other accelerometer imperfections such as non-linearity for future study. Within this framework, sensitivity-matrix errors are caused by imperfections in the construction and installation of the accelerometer calibration system, but not by the accelerometer imperfections included in the simulations. We use the results of this study to assign type B uncertainties to the components of the sensitivity matrix and related intrinsic properties due to imperfections in the measurement system. For calibrations using a reasonably well manufactured and installed multi-axis rotation stage such as that studied in this paper, we estimated upper bounds to the standard uncertainties of the order of 1 ×10−5 , 2 ×10−5 , 2 ×10−4 , and 5 ×10−5 for the intrinsic sensitivities, diagonal elements of the sensitivity matrix, off-diagonal elements of the sensitivity matrix, and zero-acceleration offsets, relative to a sensitivity-matrix element of 1, respectively, and 5 ×10−3 degrees for the intrinsic angles

Enhancing the learning and transfer of preprocedural communication skills during clerkship using audio-visual material: a prospective case-controlled study over 2 years

Objective/design/settingThis study aims to develop preprocedural communication-specific framework that emphasises the use of audiovisual materials and compares its acceptability by trainees with a regular module.TraineesBetween October 2018 and July 2021, 96 medical clerks were enrolled and randomly divided into regular and intervention groups. Another 48 trainees whose did not join the framework-based training but complete self-assessments were enrolled as the control group.InterventionsIn the intervention training module, the key steps of preprocedural communication-specific skills were structuralised into a framework using the acronym of OSCAR.Primary and secondary outcome measuresThis study compared the acceptability of trainees for two modules by measuring the degree of increase in the end-of-rotation and follow up (4 weeks later) competency from baseline by trainees’ self-assessments and physician assessments after serial trainings.ResultsIn comparison with regular group trainees, greater degree of improvements (framework-1 statement: 111%±13% vs 27%±5%, p<0.001; framework-2 statement: 77%±9% vs 48%±2%, p<0.05; skill-1 statement: 105%±9% vs 48%±3%, p<0.001); skill-2 statement: 71%±11% vs 50%±9%, p<0.05) were noted in the framework-related and skill-related statement 1–2 (the familiarity and confidence to use the framework and skills) than those of intervention group. At the end-of-rotation stage, the trainees ability to use the ‘A-step: using audiovisual materials’ of the OSCAR was significantly improved (229%±13%, p<0.001), compared with other steps. In the intervention group, the degree of improvement of the end-of-rotation data of trainees’ self-assessment from baseline was significantly correlated with the degree of the improvement in physicians’ assessment data in the aspects of skills, framework and steps in framework (R=0.872, p<0.01; R=0.813, p<0.001; R=0.914, p<0.001).ConclusionsThe OSCAR framework-based intervention module is well accepted by medical clerks and motivates them to integrate the acquired skills in clinical practice, which leads to trainees’ primary care patients being satisfied with their preprocedural communication.

X-Ray Computed Tomography Instrument Performance Evaluation, Part III: Sensitivity to Detector Geometry and Rotation Stage Errors at Different Magnifications

With steadily increasing use in dimensional metrology applications, especially for delicate parts and those with complex internal features, X-ray computed tomography (XCT) has transitioned from a medical imaging tool to an inspection tool in industrial metrology. This has resulted in the demand for standardized test procedures and performance evaluation standards to enable reliable comparison of different instruments and support claims of metrological traceability. To meet these emerging needs, the American Society of Mechanical Engineers (ASME) recently released the B89.4.23 standard for performance evaluation of XCT systems. There are also ongoing efforts within the International Organization for Standardization (ISO) to develop performance evaluation documentary standards that would allow users to compare measurement performance across instruments and verify manufacturer’s performance specifications. Designing these documentary standards involves identifying test procedures that are sensitive to known error sources. This paper, which is the third in a series, focuses on geometric errors associated with the detector and rotation stage of XCT instruments. Part I recommended positions of spheres in the measurement volume such that the sphere center-to-center distance error and sphere form errors are sensitive to the detector geometry errors. Part II reported similar studies on the errors associated with the rotation stage. The studies in Parts I and II only considered one position of the rotation stage and detector; i.e., the studies were conducted for a fixed measurement volume. Here, we extend these studies to include varying positions of the detector and rotation stage to study the effect of magnification. We report on the optimal placement of the stage and detector that can bring about the highest sensitivity to each error.

The Time Course of Event-Related Brain Potentials in Athletes’ Mental Rotation With Different Spatial Transformations

Studies have found that athletes outperformed non-athletes in mental rotation tasks with both object-based and egocentric transformations (ET), but the effect of sport expertise on the processing stages (i.e., perceptual stage, rotation stage, and decision stage) remains conflicted. Bearing the view that the stages occur sequentially and the high temporal resolution of event-related brain potentials, this study focused on brain processing during mental rotation and was designed to determine the time course of electrophysiological changes in athletes and non-athletes. A total of 42 divers and non-athletes were recruited for the study. A mental body rotation task with object-based and egocentric transformation conditions was conducted, and the reaction time (RT), accuracy, performance stages, N2 latency, amplitude, and the amplitude of rotation-related negativity (RRN) were recorded. Behavioral results demonstrated higher accuracy for athletes at 120° and 180°. Moreover, as compared to non-athletes, the enlarged amplitude of N2 and RRN were confirmed in both transformations for athletes and were correlated with the performance stages and athletes’ professional training years. The present study provided a deeper insight into the relationship between sports training, behavior performance, and brain activity.

Imaging Mass Spectrometry of Fingermarks on Brass Bullet Casings using Sample Rotation

A rotation stage was developed to allow the surface of bullet casings to be imaged under ultra-high vacuum (UHV) conditions using time-of-flight secondary ion mass spectrometry (ToF -SIMS). Experiments were...

The Importance of the Deep Deltoid Ligament Repair in Treating Supination-External Rotation Stage IV Ankle Fracture: A Comparative Retrospective Cohort Study

Background. The necessity of the deep deltoid ligament repair in the treatment of supination-external rotation (SER) ankle stage IV fracture with deltoid ligament rupture is highly debated. We conducted this retrospective research aimed at exploring the curative effect of the deep deltoid ligament repair in treating SER fracture. Methods. Sixty-three patients with closed SER stage IV fractures received open reduction and internal fixation (ORIF), using either deep deltoid ligament repair (the DDLR group, 31 patients) or nondeep deltoid ligament repair (the NDDLR group, 32 patients). The radiographic parameters examined include the talocrural angle (TA), fibular length (FL), tibiomedial malleolar angle (TMMA), medial clear space (MCS), and tibiofibular clear space (TFCS). The functional performance parameters examined in the study were visual analog scale (VAS) pain score, American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot scales, and range of motion of bilateral ankles (RMBA). Complications, including bone nonunion, infection, and fragment displacement, were also recorded and compared. Results. Similar basic characteristics were found in both cohorts. All patients completed follow-up ranging from 12 to 22 months (mean time: 12.41 ± 4.21 months). The DDLR group had significantly reduced VAS score ( p < 0.05 ), with markedly increased RMBA ( p < 0.05 ) compared to the NDDLR group. The two cohorts showed similar follow-up performance at 3 months ( p > 0.05 ), 6 months ( p > 0.05 ), and 12 months ( p > 0.05 ), in terms of parameters including TA, FL, TMMA, MCS, TCS, and AOFAS ankle-hindfoot scales. Conclusion. Although similar radiographic performances were achieved in both cohorts, the DDLR group displayed enhanced functional outcome postsurgery, indicating that DDLR may be a better potential for the treatment of SER stage IV fracture with deltoid ligament rupture.

Shallow penetrometer tests: theoretical and experimental modelling of the rotation stage

Shallow penetrometers are a new type of device that measures the properties of surficial offshore sediments via multi-phase tests involving penetration, dissipation, and rotation stages. In fine-grained soils such as silts and clays, these testing stages yield properties relevant to subsea pipeline and shallow foundation design; namely, undrained strength, consolidation, and interface friction. This paper describes the fundamentals of the rotation stage, including models required for data interpretation, encompassing both a total and an effective stress framework. Additionally, new relationships to evaluate the pore pressure scaling factor, which is a key interpretation parameter required to convert discrete measurements of pore pressure on the penetrometers to an average pore pressure over the contact area, are developed based on large-deformation finite element simulations. Results from an experimental campaign using kaolin clay samples are presented, illustrating the potential of the devices to rapidly and repeatably measure interface friction properties of fine-grained sediments offshore. The results compare well with comparative measures obtained from shear box tests conducted at similarly low effective stress levels. Recommendations regarding future in situ applications are given at end of the paper.