Standard Displacement Research Articles

An algorithm for large-span flexible bridge pose estimation and multi-keypoint vibration displacement measurement

Traditional visual vibration measurement methods face limitations in dynamic outdoor environments, making accurate multi-point vibration measurements challenging for the targeted objects. In this paper, a visual vibration measurement algorithm for large-span bridges is proposed by anthropomorphizing the bridge target and introducing key point detection at the same time. Firstly, the algorithm utilizes a convolutional neural network to extract multi-scale feature information from the image sequence of the bridge model. Secondly, to enhance target detection accuracy, a coordinate attention (CA) mechanism is incorporated, and the shape intersection over union (SIoU) loss function replaces the original loss function. Finally, the algorithm integrates the density-based spatial clustering of applications with noise (DBSCAN) and tracking algorithms to achieve precise localization of bridge targets. Vibration displacement data were extracted from a large-span suspension bridge structure in an outdoor environment and analyzed quantitatively and qualitatively. The vibration displacement curves obtained in this study show the highest level of agreement with the standard displacement signals, with a mean absolute percentage error of 0.5170% for the cable-stayed bridge model, 1.3822% for the Humen Bridge, and 3.2263% and 1.6982% for the Longjiang Bridge.

Evaluation of the Influence of Water Content in Oil on the Metrological Performance of Oil Flow Measurement Systems

According to current Brazilian regulations, if the volumes of oil produced used as a reference for the payment of government shares and third parties contain a water content greater than 2% v/v, these volumes must be arbitrarily increased between 1.44% and 10.89% due exclusively to water content, which has caused operational problems for oil companies such as differences between volumes produced and volumes sold, and additional payments from government shares and third parties. This study aimed to evaluate the metrological performance of oil measurement systems with ultrasonic, Coriolis and positive displacement flow meters when subjected to varied water content, fluid temperature and flow rate conditions using the Design of Experiments and the Response Surface Methodology. The analysis of variance showed that the models presented good fits for the ultrasonic meter (coefficient of determination R2 of 97.96%, p-value of 0.001, and a standard deviation of 5.89 × 10−5); Coriolis meter (R2 of 90.91%, p-value of 0.037, and a standard deviation of 5.88 × 10−5); and positive displacement meter (R2 of 99.07%, p-value of 0.000, and a standard deviation of 4.85 × 10−5). The results of the experiments carried out indicate that the contribution of each parameter analyzed to the metrological performance of the measurement system varies depending on the measurement technology used by the flow meter. However, the fluid temperature proved to be a relevant parameter common to all flow measurement technologies evaluated. All measuring technologies evaluated were influenced by water content in the range of 0% to 10% v/v, with the measurement error being less than 0.2% when compared to a standard positive displacement type meter in almost all experimental conditions. The Coriolis-type flow meter was the one that presented the smallest error among the measuring technologies evaluated.

Enhanced Drug Carriage Efficiency of Curcumin-Loaded PLGA Nanoparticles in Combating Diabetic Nephropathy via Mitigation of Renal Apoptosis.

The Curcuma-derived diferuloylmethane compound CUR, loaded on Poly (lactide-co-glycolic) acid (PLGA) nanoparticles was utilized to combat DN-induced renal apoptosis by selectively targeting and modulating Bcl2. Upon in silico molecular docking and screening study CUR was selected as the core phytocompound for nanoparticle formulation. PLGA-nano-encapsulated-curcumin (NCUR) were synthesized following standard solvent displacement method. The NCUR were characterized for shape, size and other physico-chemical properties by Atomic Force Microscopy (AFM), Dynamic Light Scattering (DLS) and Fourier-Transform Infrared (FTIR) Spectroscopy studies. For in vivo validation of nephro-protective effects, Mus musculus were pre-treated with CUR at a dose of 50 mg/kg b.w. and NCUR at a dose of 25 mg/kg b.w. (dose 1), 12.5 mg/kg b.w (dose 2) followed by alloxan administration (100 mg/kg b.w) and serum glucose levels, histopathology and immunofluorescence study were conducted. The in silico study revealed a strong affinity of CUR towards Bcl2 (dock score -10.94 Kcal/mol). The synthesized NCUR were of even shape, devoid of cracks and holes with mean size of ~80 nm having -7.53 mV zeta potential. Dose 1 efficiently improved serum glucose levels, tissue-specific expression of Bcl2 and reduced glomerular space and glomerular sclerosis in comparison to hyperglycaemic group. This study essentially validates the potential of NCUR to inhibit DN by reducing blood glucose level and mitigating glomerular apoptosis by selectively promoting Bcl2 protein expression in kidney tissue.

An Improved Winkler Foundation Modulus for a Beam in a Full Space

The Winkler foundation modulus is key to evaluating the response of underground structures using the elastic foundation beam model. In this paper, an improved formula of the Winkler foundation modulus for a beam embedded in a full space is proposed to overcome the limitation of inconsistent assumptions in previous studies. To achieve this goal, the bending responses of the beam are obtained using the elastic foundation beam model and three-dimensional elastic continuum model, respectively, wherein a consistent assumption is proposed that tangential interactions at the beam–ground interface are ignored in the two models. In addition, as deformation of the site is an important source of the underground structure response, the beam is applied to standard soil displacement of the free field on the Winkler foundation to improve the accuracy of the Winkler modulus obtained by fitting solutions based on the concentrated force on the beam. The formula for the Winkler foundation is obtained by equating the first zero of the bending moment in the two models. The Winkler foundation modulus is verified by comparing the results with numerical solutions and previous studies.

ScMicrobe PTA: near complete genomes from single bacterial cells.

Microbial genomes produced by standard single-cell amplification methods are largely incomplete. Here, we show that primary template-directed amplification (PTA), a novel single-cell amplification technique, generated nearly complete genomes from three bacterial isolate species. Furthermore, taxonomically diverse genomes recovered from aquatic and soil microbiomes using PTA had a median completeness of 81%, whereas genomes from standard multiple displacement amplification-based approaches were usually <30% complete. PTA-derived genomes also included more associated viruses and biosynthetic gene clusters.

Immersion Tin Plating Enabling Reliable Wettable Flanks on QFN Packages

The automotive market increasingly uses bottom-termination IC packages, like Quad-Flat No leads (QFN) packages, for miniaturization, cost reduction and performance. QFN lead frames are electroplated with 8?12 um of tin for PCB soldering, but subsequent singulation exposes the copper-alloy lead frame at the cut edges. On these exposed lead flanks a solder fillet does not form, making Automatic Optical Inspection (AOI) of solder joints on lead-less packages not reliable. A solder fillet on lead flanks also improves the reliability of solder joints. Therefore, the automotive industry strives for a tin plated wettable flank on lead-less packages. Several approaches, e.g. dimpled or step-cut leads, to create a wettable flank are in use or development. Disadvantage of these methods is that only a part of the flank is tin-plated. Immersion tin plating processes are able to fully plate lead flanks. However, the maximum ~1.5um of standard self-limiting displacement immersion tin processes is too thin to comply with the durability requirements of automotive tin solder finishes. This contribution will discuss an immersion tin-plating process, machine concept and test results for a &gt;2 um tin plated wettable flanks. The immersion tin plating process consist of the following process steps: 1. A high-pressure spray rinse prevents incomplete tin coverage by removing copper burrs formed during singulation. 2. A selective descaling process removes the natural copper oxide film on the exposed copper leads. 3. A selective activation process creates a high tin nucleation density to obtain a fine-grained tin layer. 4. The autocatalytic immersion tin process plates a 2 ? 3um tin layer in 45-60 minutes at 70-75oC. 5. An anti-tarnish process protects the tin layer against oxidation. Finally, rinsing and drying remove all traces of the used chemicals from the packages with tin plated flanks. A machine concept for the immersion tin-plating process is currently under development. The lead-less packages are processed directly on Standard singulation tape rings without repacking or manipulation of the packages. This enables a throughput of 20 tape rings per hour with the full package traceability required for the automotive market. Different types of QFN packages mounted on singulation tape were tin plated and subjected to standard (JEDEC J-STD-002E) solderability tests for component lead durability. Fine-grained 2-3 um thick pure tin deposit of good visual quality were obtained on the exposed QFN copper lead sidewalls with the following properties: • 0.5-1.5um residual tin layer after intermetallic formation in 8 h steam aging and 16 h oven bake. • 100% solder wetting after 6h dry bake at 150C • 100% solder wetting after 8h steam aging (93C and 80-90% RH). • 100% solder fillet height after ceramic glass test.

Estimation of Screw Displacement Pile-Bearing Capacity Based on Drilling Resistances

Abstract This article presents an engineering, empirical method of estimating the bearing capacity and settlement characteristics Q-s of screw displacement piles and columns, based on soil resistance encountered during the drilling to form piles/columns in the ground. The method was developed on the basis of correlation analyses of the test results of 24 piles made during the “DPDT-Auger” research project (Krasiński et al., 2022a). In the proposed method, the load capacity of a screw displacement pile is estimated using two main parameters of auger screwing resistance: torque MT and the number of auger rotations per depth unit nR . The method applies to piles and columns made with a standard screw displacement pile (SDP) auger and with the proprietary, prototype DPDT (displacement pile drilling tool) aguer, patented in Poland (2020). Based on the estimated ultimate capacities of the pile shaft and base, an approximate method of predicting the pile settlement characteristics Q-s was also proposed, using the transfer function method. This article describes a correlation procedure of field test results together with their statistical analysis and presents a method of estimating the pile-bearing capacity based on correlation results. A calculation example is also provided. The conclusion looks at the useful practical applications that could be found for the proposed method.

CARD25: Development of a Minimally Invasive Single Port Pulsatile Ventricular Assist Device

Purpose: Our goal is to develop a compact, single port, pulsatile ventricular assist device (VAD) for total left ventricle (LV) support that only requires a minimally invasive single cannulation from apex to aorta. Methods: Standard diaphragm displacement pumps have 2 valved ports and inlet/outlet cannulas to alternate between blood infusion and withdrawal. By contrast, our compact single port pulsatile VAD consists of a valved single lumen cannula and a valveless single port diaphragm displacement pump. Via a small left thoracotomy, the valved single lumen cannula is inserted from apex to aorta (Fig). Four one-way inlet valves on the valved single lumen cannula wall allow blood withdrawal from LV, and a tri-leaflet outlet valve at the cannula tip allows blood delivery to aorta. The 28 Fr valved single lumen cannula prototype was made as one piece by polyurethane (PU) dip molding with memory alloy reinforcement. The two halves of the valveless single port diaphragm displacement pump prototype housing were made by polycarbonate vacuum thermoforming and assembled with a flexible PU membrane diaphragm in the middle to separate the blood and pneumatic chambers. This pump had a 60 cc stroke volume. A closed mock loop with 37% glycerin was used to mimic the LV-aortic valve-ascending aorta tract. Priming volume and reservoir height were adjusted to maintain 70 mm Hg diastolic aortic pressure and 16 mm Hg preload. Circuit flow and pressure in valved single lumen cannula were recorded. The catheter introducer with pressure transducer on tip was inserted through apex in adult sheep (n=5, 44-52 kg), with pressure wave form guiding tip into ascending aorta. The valved single lumen cannula slid along introducer through apex, crossing aortic valve, with its tip in ascending aorta. The valved single lumen cannula was connected to the single port diaphragm displacement pump. Pumping was increased for a normal cardiac output. The single port pulsatile VAD prototype performance was assessed for 6 hrs with hemodynamics/blood counts recorded. Results: The valved single lumen cannula and single port diaphragm displacement pump prototypes were fabricated as designed. The bench study showed that the single port pulsatile VAD achieved a pumping flow of up to 3.75 L/min. Valve regurgitation was <3%. In the sheep study, the valved single lumen cannula was easily installed within 1 min at first attempt. The single port pulsatile VAD achieved maximal 3.75 L/min pumping flow in a 52 kg sheep. The single port pulsatile VAD had consistent pumping flow through 6 hrs with stable hemodynamics (Table). Hemoglobin and platelet/white blood cell counts were unchanged. No obvious injury or thrombosis in heart or single port pulsatile VAD were observed at necropsy. Conclusions: Our single port pulsatile VAD only requires a single apex cannulation with valved single lumen cannula to achieve reliable LVAD performance, showing great promise for a short to mid-term minimally invasive LVAD.Figure 1. Our single port pulsatile ventricular assist device with a valved single lumen cannula and a valveless single port diaphragm displacement pump. Table 1. - Hemodynamics and Blood Count Results Sheep 1-5 Baseline Pump Run1 hr Pump Run3 hr Pump Run6 hr sABP (mm Hg) 111±15.5 138±19.5 122±16.4 113±16.2 CVP (mm Hg) 11±0.4 11±0.8 11±0.5 11±0.8 CO (L/min) 2.5±0.38 3.8±0.98 3.6±0.66 3.5±0.66 Pump Flow (L/min) 0±0 2.8±0.65* 2.7±0.65* 2.7±0.52* HR (bpm) 154±61.1 104±44.7 105±39.3 127±16 WBC (103/uL) 4.1±0.14 N/A N/A 4.8±2.57 PLT (103/uL) 467±93.3 N/A N/A 380±171 HgB (g/dL) 9.4±0.45 N/A N/A 9.1±0.38 * p<0.05 vs Baseline sABP=systolic arterial pressure, CVP=central venous pressure, CO=cardiac output, HR=heart rate, WBC=white blood cell count, PLT=platelet count, HgB=hemoglobin, and N/A=not applicable.

GABAA receptor-mediated seizure liabilities: a mixed-methods screening approach

GABAA receptors, members of the pentameric ligand-gated ion channel superfamily, are widely expressed in the central nervous system and mediate a broad range of pharmaco-toxicological effects including bidirectional changes to seizure threshold. Thus, detection of GABAA receptor-mediated seizure liabilities is a big, partly unmet need in early preclinical drug development. This is in part due to the plethora of allosteric binding sites that are present on different subtypes of GABAA receptors and the critical lack of screening methods that detect interactions with any of these sites. To improve in silico screening methods, we assembled an inventory of allosteric binding sites based on structural data. Pharmacophore models representing several of the binding sites were constructed. These models from the NeuroDeRisk IL Profiler were used for in silico screening of a compiled collection of drugs with known GABAA receptor interactions to generate testable hypotheses. Amoxapine was one of the hits identified and subjected to an array of in vitro assays to examine molecular and cellular effects on neuronal excitability and in vivo locomotor pattern changes in zebrafish larvae. An additional level of analysis for our compound collection is provided by pharmacovigilance alerts using FAERS data. Inspired by the Adverse Outcome Pathway framework, we postulate several candidate pathways leading from specific binding sites to acute seizure induction. The whole workflow can be utilized for any compound collection and should inform about GABAA receptor-mediated seizure risks more comprehensively compared to standard displacement screens, as it rests chiefly on functional data.

Active self-motion control and the role of agency under ambiguity.

Self-motion perception is a key factor in daily behaviours such as driving a car or piloting an aircraft. It is mainly based on visuo-vestibular integration, whose weighting mechanisms are modulated by the reliability properties of sensory inputs. Recently, it has been shown that the internal state of the operator can also modulate multisensory integration and may sharpen the representation of relevant inputs. In line with the concept of agency, it thus appears relevant to evaluate the impact of being in control of our own action on self-motion perception. Here, we tested two conditions of motion control (active/manual trigger versus passive/ observer condition), asking participants to discriminate between two consecutive longitudinal movements by identifying the larger displacement (displacement of higher intensity). We also tested motion discrimination under two levels of ambiguity by applying acceleration ratios that differed from our two "standard" displacements (i.e., 3 s; 0.012 m.s-2 and 0.030 m.s-2). We found an effect of control condition, but not of the level of ambiguity on the way participants perceived the standard displacement, i.e., perceptual bias (Point of Subjective Equality; PSE). Also, we found a significant effect of interaction between the active condition and the level of ambiguity on the ability to discriminate between displacements, i.e., sensitivity (Just Noticeable Difference; JND). Being in control of our own motion through a manual intentional trigger of self-displacement maintains overall motion sensitivity when ambiguity increases.

Distance-as-time in physical aging.

Although it has been known for half a century that the physical aging of glasses in experiments is described well by a linear thermal-history convolution integral over the so-called material time, the microscopic definition and interpretation of the material time remains a mystery. We propose that the material-time increase over a given time interval reflects the distance traveled by the system's particles. Different possible distance measures are discussed, starting from the standard mean-square displacement and its inherent-state version that excludes the vibrational contribution. The viewpoint adopted, which is inspired by and closely related to pioneering works of Cugliandolo and Kurchan from the 1990s, implies a "geometric reversibility" and a "unique-triangle property" characterizing the system's path in configuration space during aging. Both of these properties are inherited from equilibrium, and they are here confirmed by computer simulations of an aging binary Lennard-Jones system. Our simulations moreover show that the slow particles control the material time. This motivates a "dynamic-rigidity-percolation" picture of physical aging. The numerical data show that the material time is dominated by the slowest particles' inherent mean-square displacement, which is conveniently quantified by the inherent harmonic mean-square displacement. This distance measure collapses data for potential-energy aging well in the sense that the normalized relaxation functions following different temperature jumps are almost the same function of the material time. Finally, the standard Tool-Narayanaswamy linear material-time convolution-integral description of physical aging is derived from the assumption that when time is replaced by distance in the above sense, an aging system is described by the same expression as that of linear-response theory.

How to commission the turbine oil system that was over years out of operation? Can heavily corroded and deposited turbine oil systems be restored

Preparation of rotating machinery oil system plays very important role in commissioning process and defines if commissioning process of the turbine brings some troubles. Moreover, future maintenance and operation is very much affected if oil system cleanliness is underestimated and machine commissioned without following complex cleaning procedure. Only standard displacement flush is not effective when system is corroded, where Varnish is agglomerated, pipe assembly done on site with lack of proper care. However, high machine availability and zero breakdowns is nowadays the main goal in every industry sectors! How to restore heavily corroded and Varnished turbine oil system after 10 years out of operation will be presented in this presentation.

Influence of Nanoaggregation Routes on the Structure and Thermal Behavior of Multiple-Stimuli-Responsive Micelles from Block Copolymers of Oligo(ethylene glycol) Methacrylate and the Weak Acid [2-(Hydroxyimino)aldehyde]butyl Methacrylate.

In this work, we compare nanoaggregation driven by pH-induced micellization (PIM) and by the standard solvent displacement (SD) method on a series of pH-, light-, and thermosensitive amphiphilic block copolymers. Specifically, we investigate poly(HIABMA)-b-poly(OEGMA) and poly(HIABMA)-b-poly(DEGMA-r-OEGMA), where HIABMA = [(hydroxyimino)aldehyde]butyl methacrylate, OEGMA = oligo(ethylene glycol)methyl ether methacrylate, and DEGMA = di(ethylene glycol)methyl ether methacrylate. The weakly acidic HIA group (pKa ≈ 8) imparts stability to micelles at neutral pH, unlike most of the pH-responsive copolymers investigated in the literature. With SD, only some of our copolymers yield polymeric micelles (34-59 nm), and their thermoresponsivity is either poor or altogether absent. In contrast, PIM affords thermoresponsive, smaller micelles (down to 24 nm), regardless of the polymer composition. In some cases, cloud points are remarkably well defined and exhibit limited hysteresis. By combining turbidimetric, dyamic light scattering, and small-angle X-ray scattering measurements, we show that SD yields loose micelles with POEGMA segments partly involved in the formation of the hydrophobic core, whereas PIM yields more compact core-shell micelles with a well-defined PHIABMA core. We conclude that pH-based nanoaggregation provides advantages over block-selective solvation to obtain compact micelles exhibiting well-defined responses to external stimuli.

A randomised controlled trial of intrapleural balloon intercostal chest drains to prevent drain displacement.

Chest drain displacement is a common clinical problem that occurs in 9-42% of cases and results in treatment failure or additional pleural procedures conferring unnecessary risk. A novel chest drain with an integrated intrapleural balloon may reduce the risk of displacement. A prospective randomised controlled trial comparing the balloon drain to standard care (12 F chest drain with no balloon) with the primary outcome of objectively defined unintentional or accidental chest drain displacement. 267 patients were randomised (primary outcome data available in 257, 96.2%). Displacement occurred less frequently using the balloon drain (displacement 5 of 128, 3.9%; standard care displacement 13 of 129, 10.1%) but this was not statistically significant (OR for drain displacement 0.36, 95% CI 0.13-1.0, Chi-squared 1 degree of freedom (df)=2.87, p=0.09). Adjusted analysis to account for minimisation factors and use of drain sutures demonstrated balloon drains were independently associated with reduced drain fall-out rate (adjusted OR 0.27, 95% CI 0.08-0.87, p=0.028). Adverse events were higher in the balloon arm than the standard care arm (balloon drain 59 of 131, 45.0%; standard care 18 of 132, 13.6%; Chi-squared 1 df=31.3, p<0.0001). Balloon drains reduce displacement compared with standard drains independent of the use of sutures but are associated with increased adverse events specifically during drain removal. The potential benefits of the novel drain should be weighed against the risks, but may be considered in practices where sutures are not routinely used.

Suture Tape Augmentation of Screw Fixation Reduces Fragment Migration in Tibial Tubercle Osteotomy: A Biomechanical Study.

Background:Tibial tubercle osteotomy (TTO) is a complex surgical procedure with a significant risk of complications, which include nonunion and tibial fracture.Purpose:To determine whether an additional suture tape augmentation can provide better biomechanical stability compared with standard screw fixation.Study Design:Controlled laboratory study.Methods:Five matched pairs of human cadaveric knees were divided into 2 groups: the first group underwent standard TTO fixation with 2 parallel screws (standard group). The second group underwent a novel fixation technique, in which a nonabsorbable suture tape (FiberTape) in a figure-of-8 construct was added to the standard screw fixation for extra stabilization in the inferior-superior direction (augmented group). The specimens were biomechanically tested using a multistep cyclic loading protocol from 400 N up to 800 N to simulate the rehabilitation process. Tubercular fragment migration of >50% of the initial distalization length was defined as clinical failure. A pull-to-failure test was applied to the specimens that survived cyclic loading. Tubercular fragment displacement during cyclic loading and pull-to-failure force were recorded and compared between the 2 groups.Results:Two specimens of the standard group exhibited clinical failure during cyclic loading to 400 N. All other specimens survived cyclic loading to 800 N. The augmented group showed less cyclic tubercular fragment displacement after every load level compared with the standard group, with statistically significant differences starting from 500 N (P < .05; power > 0.8). Mean ± standard deviation tubercular fragment displacement at the end of cyclic loading was 2.56 ± 0.82 mm for the augmented group and 5.21 ± 0.51 mm for the standard group. Mean ultimate failure load after the pull-to-failure test was 2475 ± 554 N for the augmented group and 1475 ± 280 N for the standard group.Conclusion:The specimens that underwent suture tape augmentation showed less tubercular fragment displacement during cyclic loading and higher ultimate failure forces compared with those that underwent standard screw fixation.Clinical Relevance:The augmentation technique could potentially increase the success of a TTO.

Vehicle trajectory prediction and generation using LSTM models and GANs.

Vehicles' trajectory prediction is a topic with growing interest in recent years, as there are applications in several domains ranging from autonomous driving to traffic congestion prediction and urban planning. Predicting trajectories starting from Floating Car Data (FCD) is a complex task that comes with different challenges, namely Vehicle to Infrastructure (V2I) interaction, Vehicle to Vehicle (V2V) interaction, multimodality, and generalizability. These challenges, especially, have not been completely explored by state-of-the-art works. In particular, multimodality and generalizability have been neglected the most, and this work attempts to fill this gap by proposing and defining new datasets, metrics, and methods to help understand and predict vehicle trajectories. We propose and compare Deep Learning models based on Long Short-Term Memory and Generative Adversarial Network architectures; in particular, our GAN-3 model can be used to generate multiple predictions in multimodal scenarios. These approaches are evaluated with our newly proposed error metrics N-ADE and N-FDE, which normalize some biases in the standard Average Displacement Error (ADE) and Final Displacement Error (FDE) metrics. Experiments have been conducted using newly collected datasets in four large Italian cities (Rome, Milan, Naples, and Turin), considering different trajectory lengths to analyze error growth over a larger number of time-steps. The results prove that, although LSTM-based models are superior in unimodal scenarios, generative models perform best in those where the effects of multimodality are higher. Space-time and geographical analysis are performed, to prove the suitability of the proposed methodology for real cases and management services.

Touch Probe Measurement in Dimensional Metrology: A Review

Coordinate measuring machines (CMMs) are the standard displacement systems used for measurements in dimensional metrology. Since measurement with a touch probe mounted on a CMM provides high accuracy, repeatability, and reliability, it has been widely used for mechanical part inspection in manufacturing. The inspection process requires the use of several sensor orientations and optimal positioning of the part in order to measure all features. Recently, the field of probing path planning has become a huge and active research field. In this paper, various techniques aimed at generating the probe paths for part inspection are reviewed. Multiple issues related to the positioning of the part to maximise accessibility, analysis of probe accessibility to measure all inspection features, optimisation of the measurement sequence, distribution of measurement points, and collision avoidance are mentioned. The common research approaches and potential algorithms in this field are also discussed in this paper.

Calibration of gas flow meters using choked flow and an evacuated vessel

The measurement of gas flow rates is of great importance in a wide range of modern technologies. This paper introduces a simple, yet accurate technique for in-house calibration of gas FMs (mass and volumetric) even under harsh environmental conditions such as encountered during field measurement campaigns. The method requires only readily available, low cost components: a vessel of known volume, an air pump, a pressure sensor and a metal plate orifice or a needle valve to act as a CO. The unique property of choked flow in the CO is used here for flow calibration. In the method presented here a vessel is evacuated to below the critical pressure (<0.53 of upstream pressure) and then allowed to refill with ambient air (or some other process gas) under so-called choked flow conditions through the CO. The method presented here leverages that the flow rate upstream of the CO is not only constant but readily determined from (a) the known V VESS, (b) the measured time rate of change of the absolute pressure in the vessel and (c) the ideal gas law. This calculated flow rate can be used for calibration of FMs. The accuracy of the method depends only on the accuracy of the pressure measurement, the timer and the value of the V VESS. The flow rate computed in this way is found to be in excellent agreement (typically 1% difference) with the flow rate measured by a soap film FM (Gilibrator). As expected from theory this method is found to work for all kinds of CFRs (here: various types of metal plate orifices and needle valves were tested), gas types (here: air, Argon, and CO2) and upstream pressures (here: between 650 hPa and 1400 hPa). The accuracy of this technique (∼1%) is as good as that of standard volume displacement methods (e.g. soap film FMs) (typically 1% difference), the standard of laboratory-based flow calibrators, but less expensive and more suitable for harsh environments.

Structural optimal hybrid control strategies employing dynamic dual units: inerter and spring

AbstractThe concepts of optimal hybrid control strategies in the time and frequency domains are proposed herein. The time‐domain optimal hybrid control (also called GangGang strategy) consists of two dynamic units, an inerter and a spring, which work with different force mechanisms at different time phases of vibrations. The inerter acts on the structure when the vibration phase is accelerated, whereas the spring works when the structure deviates from its initial position. The combination of the two piecewise working units achieves better performance than their individual full‐time operations. The working time phases of the two units are complementary, covering the entire vibration period. The hysteresis loops of them are also complementary in the quadrant coordinate system. Owing to the piecewise properties of the two units, the equivalent linearization system (ELS) of such systems is formulated, and a statistical linearization procedure is developed to obtain the equivalent linearization parameters. Then, a parametric study on the equivalent damping is performed through sensitivity analysis and a comparative analysis of the ELS was performed in terms of the standard deviation and peak displacement levels under stationary stochastic excitations. The frequency‐domain optimal hybrid control conforms with the concept of intelligent isolation. The inerter and spring units can be switched according to the excitation frequency by an on–off control benefitting structures subjected to excitations with definite frequency range.

Fracture toughness assessment at different regions in an inertial friction welded Ti-5Al-2Sn-2Zr-4Mo-4Cr alloy plate

Abstract The study aims to ascertain the influences of position on fracture toughness and fracture mechanism of inertial friction welded Ti-5Al-2Sn-2Zr-4Mo-4Cr joints. The room-temperature fracture toughness values of the parent material and three other regions in the weld were evaluated by standard crack tip opening displacement tests. The micro-structure and tensile properties of the welds were also investigated. Based on the observation of fracture surface and crack propagation path, a schematic illustration of the crack propagation was formed. The results suggest that the weld metal had the worst fracture toughness. The individual fracture toughness of different regions in the weld could be explained by the various modes of crack propagation, which were affected by different microstructures.