Ametek (Germany)

Background: Despite evolution in decompression algorithms, decompression illness is still an issue. Reducing vascular gas emboli (VGE) production by varying decompression procedures is very common among divers. Several methods have been tried, either mechanical, cardiovascular, desaturation-aimed or biochemical, with encouraging results. In this study, we tested two different decompression methods: one called DEEP, where the decompression starts deeper, the other one SHALLOW, where shallower stops were planned, for the same dive and decompression time. Material and methods: In total, 18 healthy, non-smoking divers participated [1 female, 17 males; mean age 44.94 ± 5.74 years; body mass index (BMI) 27.3 ± 5.9 kg/m2]. Each diver performed two standardized Open Circuit trimix (21/35) dives, decompression mix EAN50. The deep profile used stops at 21, 18, 15, 12, 9, 6, and 3 meters. The shallow profile used stops at 9, 6, 3, with the same total bottom and decompression times for both groups. All dives were done in a pool (Y-40, Montegrotto, Italy) at a depth of 40 m for 40 min of bottom time and 80 minutes of total runtime. VGE counts were recorded every 15 min from 0 (0–5 min) to 90 min by echocardiography. Results: Vascular gas emboli were significantly reduced after the deep stops decompression procedure (DEEP: 6.7 ± 7.2 VGE per heartbeat vs. shallow: 10.7 ± 11.6 VGE per heartbeat, p = 0.0006). Three DCS cases were recorded after the “shallow” stop procedure (p = 0.24 Fisher’s exact test). Conclusions: There are significant differences between the two tested decompression procedures. The DEEP procedure resulted in a lower production of bubbles compared to the SHALLOW procedure.

This paper investigates the feasibility of measuring form error of all the optical surfaces on a lens in a single setup using a dual tipped diamond stylus. Two lenses were measured with a dual, 2 μm conisphere tipped, diamond stylus on a tactile profilometer having a phase grating interferometer (PGI) gauge. When the lens was mounted in a horizontal orientation, one of the stylus tips was used to measure the optical surface on top of the lens (hereafter referred to as measurement using normal bias), whereas the other stylus tip (180˚ opposite) was used to measure the optical surface on bottom of the lens (hereafter referred to as measurement using reverse bias). To validate the results from the measurement using reverse bias, a given optical surface was measured using both normal bias and reverse bias of the PGI gauge with a suitable fixture. Moreover, this surface was also measured on a LuphoScan instrument, a 3D non-contact profiler based on multiwavelength interferometry, and an average form error profile was extracted from the 3D surface form error map. Surface form was quantified by evaluating peak-to-valley (PV), and root mean square (RMS) parameters to compare the results obtained from measurements using normal bias, reverse bias, and multiwavelength interferometer. It is shown that there is a good agreement not only between normal bias and reverse bias measurements using PGI gauge but also with measurement performed on multiwavelength interferometer. With this additional capability of PGI gauge to measure form error of all the optical surfaces in a single setup, results from both surfaces can be correlated to determine wedge, commonly referred to as inner centration, decenter error between the two surfaces, and thickness of the lens under test.

In the process of coal mining, pressure will be induced in the working face, resulting in the stress concentration of surrounding rock, which will affect the safety and orderly normal operation of coal energy mining. The all-fiber optic micro-seismic monitoring technology offers advantages such as high sensitivity, wide dynamic range, and passive front-end intrinsic safety, resolving the conflict between high sensitivity and broadband frequency response. This technology enhances both the sensitivity and frequency response range of micro-seismic monitoring, enabling effective real-time monitoring of pressure-related activities in coal mines. Taking the II1012 working face of Taoyuan Coal Mine as the engineering background, the all-fiber optic micro-seismic monitoring work is carried out, and the data are analyzed by the methods of micro-seismic event detection, identification, classification and location. The characteristics of micro-seismic activity during the first weighting (the mine pressure appears before and after the primary fracture of the basic roof), periodic weighting (the mine pressure of the old roof is manifested by periodic fracture or collapse) and square pressure (the mining pressure of the working face is equivalent to the length of the cutting hole) are studied. The results show that: High-energy events in the first weighting stage play a major role in roof failure. In the periodic weighting stage, the influence of micro-seismic activity on the roof is greater than that on the floor, but the influence on the floor is increasing. The high-energy events increase significantly in the square pressure stage, which is easy to promote the frequent occurrence of high intensity and stress micro-seismic activities. The occurrence of micro-seismic events in mine pressure phases have advanced characteristics. There is a positive correlation between the intensity of micro-seismic activity and the rate of recovery, and the all-fiber optic micro-seismic has a good response to the mine pressure. The research work provides theoretical basis and technical support guidance for the safe production of the II1012 working face in Taoyuan Coal Mine and other similar working faces in other coal mines, reduces the risk of geological disasters caused by micro-seismic events during the pressure period, and further guarantees the safe and normal orderly development of the subsequent production work of the working face. It is of great significance to the safe mining of coal energy and the supply of production and life.

Abstract Improving the deformation behaviour of titanium alloys at intermediate temperatures is crucial for cost and energy savings in forming processes. In this context, the modification of the microstructure prior to forming is of great importance. Here we show how the deformability of α-β titanium sheets at 500°C can be significantly increased via a tailored pre-heating procedure in the range of 750–950°C, with an optimal range of 790–850°C. Depending on the pre-heating temperature and the subsequent cooling conditions, major changes in hardening behaviour were achieved, resulting in increased elongation and/or tensile strength. Based on these results, an elongated cup was deep drawn at 500°C after the pre-heating treatment, offering an attractive alternative to the costly and time-consuming superplastic forming process. Our results highlight the potential to develop an economic production process for thin-walled titanium components via deep drawing at intermediate temperatures.

Abstract We have found deviations in in net-count measurement comparisons with EDS detectors equipped with different X-ray entrance windows that cannot be explained by the theoretical assumed and synchrotron measurements verified window transmissions. This work presents the results with systematic simultaneous measurements, which were performed with two EDS SDD systems on one SEM to verify this effect. The two detectors were equipped with a polymer window (Moxtek AP3) and the next generation Si3N4-window (Amptek C2), respectively. A possible explanation of measured detector-efficiency deviations will be given with an additional “divergence effect” due to the Moxtek polymer window support grid blades. It is to consider an additional X-ray transmission at window support grid lamella edges for divergent X-rays at energies already below 10 keV, while the support grid becomes significantly transparent in the parallel beam only with energies >10 keV. This effect is to consider in difference to the parallel beam transmission view because the X-rays in the SEM are from a point source, a fact which was ignored in the past. The “divergence effect” increases with detector area and with closer detector distance to the specimen in SEM. Small deviations of grid lamella alignment to the detector axis can produce similar lamella-edge transmission effects, which can differ between individual detectors. Taking the additional polymer window grid-lamella transmission into account explains the already observed and reported systematic difference in the calculated X-ray counts emitted from a specimen (measured net counts corrected with detector-efficiency). And with this, it explains the deviations of quantitative results between the two different detector window systems. Standardless quantitative results need to be independent from the detector (window) with which the measurements were performed. This was the motivation for the presented work and is a precondition to investigate and improve the standardless quantitative models further, to achieve improved accuracy in standardless evaluation of the measured X-ray data with energy-dispersive X-ray spectrometry (EDS) systems, used for the electron probe microanalysis (EPMA) method.

This paper investigates the feasibility of measuring surface form of freeform optics using non-contact multiwavelength interferometry. A bi-conic lens, which is one of the most fundamental freeform optics, was measured on a non-contact multiwavelength interferometer. This lens was characterized by two infinite (flat) radii of curvature along x- and ydirection and two aspheric terms along each direction. Peak-to-valley (PV), root mean square (RMS), and radius of curvature (RoC) parameters were evaluated to characterize the surface form of this lens. To evaluate the measurement repeatability, 5 consecutive measurements were performed on this lens, and it was observed that the standard deviation (3) of PV and RMS was around 29.3 nm and 3.8 nm respectively.

Coincidences in La-138 are simulated with the Monte-Carlo solver tRAYcy, modelling the intrinsic activity $\mathrm{LaBr3}: \mathrm{Ce}, \mathrm{Sr}$ detector [1] and the influences of additional potassium K-40. Based on this data, a decision tree regressor [2] is trained to estimate a numerical value for contribution of additional K-40, to improve retrieval of the peak position. Lanthanum bromide, typically doped with Cerium or Strontium ($\left.\mathrm{LaBr}_{3}: \mathrm{Ce}, \mathrm{Sr}\right)$ has become a versatile detector material in the high resolution market of scintillators. With an FWHM often better than 3%, the material is a notable attractor for homeland security applications [3]. Due to its intrinsic activity of La-138 [4], this scintillator shows a complex background radiation spectrum containing many features - a fact thoroughly discussed in literature. Some users understand this background radiation as distortion, yet it is also known to be exploitable for automatic calibration against peak shifts. The most prominent feature of the LaBr3:Ce,Sr intrinsic background is a peak structure at between 1435 keV and 1468 keV. It is due to a coincidence of the La-138 gamma line at 1435.7 keV and its series of X-rays emitted between 4 keV and 37 keV. The 1460 keV gamma line of natural K-40 usually overlaps with this LaBr3 structure, even increasing the complexity of the spectroscopic structure. The paper presents a novel technique that decomposes the overlapping to find an accurate gain prediction for stabilisation. The proposed decision tree uses the Gini-Impurity as measure for splitting its nodes and yields reasonable performance on finding the right K-40 amount just based on shape analysis. The stabilisation is further tested with a detector in a laboratory climate chamber during temperature ramps to emulate real-life usage e.g. for nuclear security scenarios.

Ostwald ripening, as a well-known classic crystal growth mode, was introduced into the field of electrochemical energy storage by Wei Zhang, Weitao Zheng et al. in their Research Article (e202414420). The transition metal ions dissolved in CuHCF undergo a crystallization process (Kongming lantern) and evolve into a stable interfacial layer (shining dome) via Ostwald ripening during electrochemical cycling. Through this process, the stability of the electrode and of the electrode/electrolyte interface are drastically improved.