Metrological Evaluation of Deep-Ocean Thermometers

An accurate metrological investigation was performed on several units of the two de facto standards for deep-ocean temperature measurements—the SBE35 (the reference thermometer) and the SBE3 (the working thermometer) from SeaBird Scientific. Four SBE35 units were repeatedly calibrated against state-of-the-art fixed-point cells (triple point of water at 0.01 °C and melting point of gallium at 29.7646 °C), with calibration uncertainties of approximately 0.2 mK and 0.5 mK, respectively. Three SBE35 units and one SBE3 unit were calibrated in the temperature range 0 °C to 30 °C, again with sub-millikelvin calibration uncertainties, in a recently-developed water–bath calibration facility. All these calibrations evidenced (1) the deviation of each unit from its original manufacturer’s calibration (up to 1.7 mK), which were found to be inconsistent with the manufacturer’s uncertainty claims and (2) unexplained irreproducibilities, which could not be attributed to the calibration system of up to 1.5 mK. The effect of high pressures (up to 60 MPa) on the response of two SBE35 units was investigated by pressurizing the SBE35 units inside a purpose-built compact pressure enclosure. The results of the pressure investigation confirmed the existence of a small device-dependent pressure effect (approximately 0.3 mK at 60 MPa) and the need for individual temperature–pressure calibration of each SBE35 unit.

Einsatz von Industrierobotern in der Zerspanung/Use of industrial robots in machining - metrological investigation on how the radial depth of cut influences the machining accuracy in robot-guided machining

Der zunehmende Einsatz von Industrierobotern in der Zerspanung setzt eine deutliche Erhöhung der Bearbeitungsgenauigkeit voraus. Dies bedingt aufgrund der Steifigkeitseigenschaften von Robotern eine Optimierung der Bearbeitungsstrategien und Zerspanparameter. Der Beitrag beschreibt die experimentelle Untersuchung des radialen Arbeitseingriffs bei der Kunststoffzerspanung, um über die Wahl geeigneter Eingriffsgrößen das Schwingungs- und Abdrängungsverhalten des Roboters und damit die Bearbeitungsqualität zu verbessern.   The prerequisite for an extended use of industrial robots in machining is a significant increase in machining accuracy. This requires an optimization of machining strategies and cutting parameters due to the stiffness of the robot. This paper presents an experimental investigation of the radial depth of cut in plastics machining to improve both the vibration and displacement behavior of the robot and the machining quality by selecting suitable intervention variables.

ASPECTS, The Mismeasure of Stroke: A Metrological Investigation

ASPECTS (Alberta Stroke Program Early CT Score) is an irregular scoring systemthat reads out as 10 to 0 points. It was originally conceived to reflect acute MCA (middle cerebral artery) territory infarct volume on (plain) CT, but it is equally applicable to and testable by MRI.Background material prepares the reader by explaining pertinent measurement principles and ASPECTS’s genesis, definitions, claims, and quirks. This report investigates ASPECTS as a volume surrogate without independently advocating for or against the therapies it might help plan.Method: The original authors of four publications provided their unpublished primary numerical data for further analysis. A CT study expands on the ACCESS database, which compares ASPECTS with two other subjective infarct scales: the legacy 1/3 MCA estimate and the multivariate IST-3 scale. An MRI study pools three diffusion-weighted (DWI) series as a patient-level meta-analysis unifying their comparisons of ASPECTS to the volumes that were found by semiautomated measurement.CT results: ASPECTS is unreliable, showing wide interrater variation with three quantifiable effects. It delivers little more than half as much entropy reduction as the IST-3 scale shows CT can support. Its large standard deviation (SD) takes up much of the scale width. Converting SD to a loss function with respect to a reference standard neuroradiologist gives an alarming weighted measure of error in ratings.MRI results: There are many-fold ranges of volume per ASPECTS and of ASPECTS per volume, causing sometimes large misclassifications one or both ways by any ASPECTS dichotomization. Looking past the ranges to averages, an estimate of 1/3 of the MCA territory corresponds best to ASPECTS cutting between 6 and 5 (6//5) and a volume of 65 mL (<1/4 of the average MCA territory).Discussion: There is already a simple, quick, and reliable manual volume measure (ABC/2, 2Sh/3). An attempt to salvage ASPECTS by reinterpreting its purpose does not hold up under scrutiny. ASPECTS can be replaced in stroke guidelines: the guideline cutting at ASPECTS 6//5 is consistent on average with the increasingly commonly stated, and better defined, 70 mL threshold. Arguments defending ASPECTS are rebutted by the evidence herein and by literature citations.Conclusion: ASPECTS subtracts value from the more objective direct volume measurements that are universally available by manual calculation and are becoming available by automatic software. ASPECTS inherently risks clinically significant misclassification (harm) for many patients.

Intra- and Inter-Repeatability of Profile Deviations of an AlSi10Mg Tooling Component Manufactured by Laser Powder Bed Fusion

Laser powder bed fusion (LPBF) is one of the most potent additive manufacturing (AM) processes. Metallic LPBF is gaining popularity, but one of the obstacles facing its larger industrial use is the limited knowledge of its dimensional and geometrical performances. This paper presents a metrological investigation of the geometrical and dimensional deviations of a selected LPBF-manufactured component, according to the ASME Y14.5-2009 standard. This approach allows for an estimation of both the process capability, as per ISO 22514-4 standard, and the correlations between the part location in the manufacturing chamber and the profile deviations. Forty-nine parts, which are representative of a typical aerospace tooling component (30 mm in diameter and 27.2 mm in height) were manufactured from AlSi10Mg powder using an EOSINT M280 printer and subjected to a stress relief annealing at 300 °C for two hours. This manufacturing procedure was repeated three times. A complete statistical analysis was carried out and the results of the investigation show that LPBF performances for all geometrical variations of 147 identical parts fall within a range of 230 µm at a 99.73% level.

Agro-metrological investigation of bumper apple productivity in Himachal Pradesh, India

The study aimed to investigate the productivity and weather relationship for the apple growing areas of Himachal Pradesh viz., Kalpa, Bhuntar and Shimla in district Kinnaur, Kullu and Shimla, respectively. The results revealed that pre bloom period (November to February) in the year 2009-10 remained cooler. The minimum temperature of 0.4 to 0.9, 1.0 to 1.1°C and 1.9 to 2.2°C and maximum temperature of 6.7, 1.0 to 1.1 and 1.7°C were lower in Shimla, Bhuntar and Kalpa region, respectively compared to 1995-2009.. The maximum temperature for the chill accumulation months of November, December, January and February during 2009-10 showed 13 to 19 per cent lower compared to 1995-2009. The average pre bloom rainfall during 2010 was 39 to 57 per cent higher than 1995-2009 indicating sustainable bloom period. The 3 to 4°C temperature rise during March 2010 (19 to 24°C) as compared to 1995-2009 (16 to 21.4°C) coupled with 52 per cent higher precipitation benefited the crop in profuse flowering and hence good fruit set. The average maximum temperature during the post bloom period (May-June) in 2009-10 was 1°C higher compared to the previous years coupled with 23 per cent higher rainfall resulting in an highest productivity. The highest productivity (8.57 MT/ha) during 2010 which was 58 per cent higher than the previous years can be ascribed due to the favorable low temperature in pre bloom period and increase in the temperature inthe month of March along with adequate rainfall in the bloom and post bloom period.

Improving mean time to develop micro-bump/pillar fabrication process for vertical interconnections by combined defectivity and metrology approach

In this paper, we explored a new process development concept that was recently introduced at CEA/LETI MINATEC campus to minimize the Mean-Time-To-Detection (MTTD) of fabrication problems. This innovative approach aims to speed up the learning curve and reduce its associated cost when developing new innovative technologies. The basic idea is to mix defectivity with metrology by feeding one with the other through a unique hardware/software platform. As a case study, we characterized the fabrication process of a micro-bump and pillar by using information from automatic visual inspection to drive the local metrological investigation. Therefore, the targeted metrology will gain time on root cause findings. Combined results were analyzed automatically, so as to optimize and maintain the related fabrication process.