Optical Sensor Assembly On Knee Brace For Continuous Knee Monitoring Application

Knee joint is an important part of human body. People with poor knee condition generally have limited physical movement, rendering to mental stress and agony. Knee pain can be categorized into three groups, known as acute injury, chronic injury and medical condition. Current technology to support the knee diagnosis and treatment procedures are limited to the use of manual goniometer, x-ray and magnetic resonance imaging (MRI). Alternative devices with continuous measurement capability for knee monitoring are minimum at this time, mainly due to the difficulties to cover the wide angle of the knee flexion. X-ray and MRI technologies are useful to have some insight on the knee problem, but they are not applicable for continuous monitoring. Aside from being expensive for general use of MRI, x-ray on the other hand can cause short-term side effects due to radiation exposure. The aim of this paper is to demonstrate the use of optical sensor integrated with mechanical gear system as a knee monitoring device. A plastic compartment, made by using 3D printer is used to place the sensor and the gear system. The design of the overall device allows direct attachment on a knee brace for easy placement on the knee. Based on current study, the proposed sensor has a range of motion between 0 deg. to 160 deg., 0.08 deg. resolution as well as support continuous monitoring of the knee. The sensor performance has been demonstrated for gait motion, ascending and descending stairs, sit-to-stand movement and maximum knee flexion applications.

Dynamical and surface impacts of the January 2021 sudden stratospheric warming in novel Aeolus wind observations, MLS and ERA5

Major sudden stratospheric warmings (SSWs) are extreme dynamical events where the usual strong westerly winds of the stratospheric polar vortex temporarily weaken or reverse and polar stratospheric temperatures rise by tens of kelvins over just a few days and remain so for an extended period. Via dynamical modification of the atmosphere below them, SSWs are believed to be a key contributor to extreme winter weather events at the surface over the following weeks. SSW-induced changes to the wind structure of the polar vortex have previously been studied in models and reanalyses and in localised measurements such as radiosondes and radars but have not previously been directly and systematically observed on a global scale because of the major technical challenges involved in observing winds from space. Here, we exploit novel observations from ESA's flagship Aeolus wind-profiler mission, together with temperature and geopotential height data from NASA's Microwave Limb Sounder and surface variables from the ERA5 reanalysis, to study the 2021 SSW. This allows us to directly examine wind and related dynamical changes associated with the January 2021 major SSW. Aeolus is the first satellite mission to systematically and directly acquire profiles of wind, and therefore our results represent the first direct measurements of SSW-induced wind changes at the global scale. We see a complete reversal of the zonal winds in the lower to middle stratosphere, with reversed winds in some geographic regions reaching down to the bottom 2 km of the atmosphere. These altered winds are associated with major changes to surface temperature patterns, and in particular we see a strong potential linkage from the SSW to extreme winter weather outbreaks in Greece and Texas during late January and early February. Our results (1) demonstrate the benefits of wind-profiling satellites such as Aeolus in terms of both their direct measurement capability and use in supporting reanalysis-driven interpretation of stratosphere–troposphere coupling signatures, (2) provide a detailed dynamical description of a major weather event, and (3) have implications for the development of Earth-system models capable of accurately forecasting extreme winter weather.

Report on the AFRIMETS.M. F-S1 supplementary force comparison for 10 kN and 100 kN

Main text This bilateral comparison of Force Standard Machines (FSM) named AFRIMETS.M. F-S1 was carried out in the force range from 1 kN to 100 kN between Physikalisch-Technische Bundesanstalt (PTB) of Germany as the pilot laboratory and Kenya Bureau of Standards (KEBS) of Kenya as the participant laboratory. KEBS had already participated in the APMP.M. F-K2 key comparison where measurements were made only at 50 kN and 100 kN force steps. Therefore, this bilateral comparison was planned to thoroughly compare the KEBS FSM and the PTB Deadweight Machines in wider force steps than those of the APMP.M. F-K2 key comparison and thus it had no corresponding key-comparisons values to be linked to at that time. PTB provided two force transducers for the supplementary comparison with 10 kN and 100 kN nominal capacities. The comparison method called "DKD" procedure was used. This procedure has already been used in several comparisons in Germany and other countries. The purpose to this comparison is to give support to the uncertainty claims for KEBS and will be used to determine the Calibration and Measurement Capability (CMC). In addition, this comparison will provide metrological proof of the application for a CMC entry in the BIPM Key Comparison Database (KCDB). This report describes the scheme and results of the comparison. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Segmentation phase measuring deflectometry for measuring structured specular surfaces

Accurate and fast three-dimensional (3D) measurement for industrial products/components designed to possess 3D structured shapes is a key driver for improved productivity. However, challenges for current techniques are considerable to measure structured specular surfaces. A technique named segmentation phase measuring deflectometry (SPMD) is proposed in this paper, which enables structured specular surfaces to be measured with high accuracy in one setup. Concept of segmentation in topology is introduced into phase measuring deflectometry, which separates a surface with complex structures into continuous segments. Each segment can be reconstructed based on gradient information to achieve good form accuracy, and all reconstructed segments can be fused into a whole 3D strucutred form result based on their absolute spatial positioning data. Here, we propose and discuss the principle of SPMD, a segmentation technique to separate a strucured surface into segments, a spatial positioning technique to obtain absolute position of the segments, and a data fusion strategy to fuse all reconstructed segments. Experimental results show SPMD can achieve nanometer level accuracy for form measurement of continuous segments by comparing with stylus profilometer, which is significantly higher than the accuracy of direct phase measuring deflectometry. Meanwhile, SPMD has micron level spatial positioning accuracy for structures by measuring two specular steps and comparing with coordinate measuring machine, which differentiates this technique from gradient-based phase measuring deflectometry that extends measurement capability from continuous specular surfaces to complex structured specular surfaces. Compared with the existing measurement techniques, SPMD significantly improved the convenience and ability to measure freeform and structured specular surfaces with the advantages of high measurement accuracy, fast measurement, and potential application for embedded measurement.

Investigation of Stress State During Cement Hardening and its Effect on Failure of Cement Sheath in Shale Gas Wells

Consideration of initial stress state after cement hardening provides a vital basis for the prediction of cement failure, which has been overlooked in previously published methodologies partly due to the difficulties in examining this problem rationally. In the present study, the hoop stress at casing-cement interface during cement hardening is investigated experimentally based on the full-scale casing-cement sheath-formation system (CCFS) facility, which is equipped with the real-time stress-strain measurement capability. The hoop stress at casing-cement interface during cement hardening drops sharply, rather than equating with the initial annulus pressure of cement slurry. It presents a higher drawdown under higher annulus pressure and thinner casing, and a lower drawdown under elastic cement slurry and thicker cement sheath. Furthermore, an analytical model taking the effect of cement hardening into account is developed to predict the integrity of cement sheath. Reliability of the model is verified by comparison with field observations. Excellent agreements are observed. The results illustrate that the tensile cracks are likely to occur at the inner cement (inner surface of cement sheath) by the effect of cement hardening, since the hoop stress at inner cement during cement hardening drops greatly and even becomes tensile. A detailed sensitivity analysis illustrates that an elastic cement slurry with a lower elastic modulus works more effectively, which can resolve the SCP problem in shale gas wells.

Aerosol Analysis Using Handheld Raman Spectrometer: On-site Quantification of Trace Crystalline Silica in Workplace Atmospheres

A method for aerosol chemical analysis using handheld Raman spectrometer has been developed and its application to measurement of crystalline silica concentration in workplace atmosphere is described. The approach involves collecting aerosol as a spot sample using a wearable optical aerosol monitor, followed by direct-on-filter quantitative analysis of the spot sample for crystalline silica using handheld Raman spectrometer. The filter cassette of a commercially available optical aerosol monitor (designed to collect aerosol for post-shift analysis) was modified to collect 1.5-mm-diameter spot sample, which provided adequate detection limits for short-term measurements over a few tens of minutes or hours. The method was calibrated using aerosolized α-quartz standard reference material in the laboratory. Two Raman spectrometers were evaluated, one a handheld unit (weighing less than 410 g) and the other a larger probe-based field-portable unit (weighing about 5 kg). The lowest limit of quantification for α-quartz of 16.6 μg m−3 was obtained using the handheld Raman unit at a sample collection time of 1 h at 0.4 l min−1. Short-term measurement capability and sensitivity of the Raman method were demonstrated using a transient simulated workplace aerosol. Workplace air and personal breathing zone concentrations of crystalline silica of workers at a hydraulic fracturing worksite were measured using the Raman method. The measurements showed good agreement with the co-located samples analyzed using the standard X-ray powder diffraction (XRD) method, agreeing within 0.15–23.2% of each other. This magnitude of difference was comparable to the inter- and intra-laboratory analytical precision of established XRD and infrared methods. The pilot study shows that for silica-containing materials studied in this work it is possible to obtain quantitative measurements with good analytical figures of merit using handheld or portable Raman spectrometers. Further studies will be needed to assess matrix interferences and measurement uncertainty for several other types of particle matrices to assess the broader applicability of the method.

Measurement Capability of Laser Ultrasonic Inspection System for Evaluation of Ball-Grid Array Package Solder Balls

Laser ultrasonic inspection is a novel, noncontact, and nondestructive technique to evaluate the quality of solder interconnections in microelectronic packages. In this technique, identification of defects or failures in solder interconnections is performed by comparing the out-of-plane displacement signals, which are produced from the propagation of ultrasonic waves, from a known good reference sample and sample under test. The laboratory-scale dual-fiber array laser ultrasonic inspection system has successfully demonstrated identifying the defects and failures in the solder interconnections in advanced microelectronic packages such as chip-scale packages, plastic ball grid array packages, and flip-chip ball grid array packages. However, the success of any metrology system depends upon precise and accurate data to be useful in the microelectronic industry. This paper has demonstrated the measurement capability of the dual-fiber array laser ultrasonic inspection system using gage repeatability and reproducibility analysis. Industrial flip-chip ball grid array packages have been used for conducting experiments using the laser ultrasonic inspection system and the inspection data are used to perform repeatability and reproducibility analysis. Gage repeatability and reproducibility studies have also been used to choose a known good reference sample for comparing the samples under test.

A Guide to Standardizing Digital Calibration and Measurement Capabilities

Demand for transparent digital measurement data exchange and processing continues to grow in the metrology industry. Automated data processing, however, requires metadata to adequately describe and identify the information content. In metrology, the measurand description comprises the fundamental metadata that associates meaning with measurement data. Measurement information exists in many metrological documents, including calibration certificates and instrument specifications, but in the international quality infrastructure (IQI), CMC1 descriptions define all approved and accredited measurands. These CMCs appear atthe IQI’s apex in the BIPM2 KCDB3 and throughout the IQI in official accreditation scopes and unaccredited measurement capability statements. In the current state of the art, metrology experts develop CMCs primarily as free-form text that often lacks full information, requires subject-matter experts to interpret correctly, hinders machine processing, and does not lend itself to contextual or semantic search on CMC technical characteristics of interest: uncertainty, range, or even the specific measurand. This paper describes a measurand taxonomy structure suitable for use as CMC metadata and provides a procedure and examples for developing the metadata taxons to standardize CMCs in human- and machine-readable formats.

Thermal Profiling of Automotive Turbochargers in Durability Tests

A major portion of the development of an automotive powertrain system is devoted to robustness and durability testing to ascertain the viability of the design. For turbochargers, thermo-mechanical fatigue is often considered as life limiting failure mechanism for the turbine section, therefore, these tests involve repeated and continuous cycling of the turbocharger for hundreds of hours. The Thermal History Coatings (THC) can offer a new and unique solution. THCs are applied to the surface of a component and, when heated, the coating permanently changes according to the maximum temperature of exposure. The technique has been used in several turbomachinery, and other applications to capture the spatial temperature distribution of critical components. However, the turbocharger durability test presents new challenges for the technique. It has not been tested in this type of application and repeated cycling operation can test the response of the coating on the temperature measurements. In this paper, the capability of the THC for this application was investigated. For the first time, the effect of cyclic operation on the THC is reported. The measurement capability was demonstrated on two turbine housings tested on a gas stand, one for a single cycle, another for 10 cycles. The results show that the surface temperature profile of the two turbine housings can be accurately recorded and the results are validated against the installed thermocouples. The demonstration indicates that the THC can be used to acquire accurate and detailed spatial temperature distributions. This information improves the interpretation of a durability test.