Axis Configuration Research Articles

Influence of left ventricle longitudinal axis translation on rotation measurements in 3D echocardiography

ABSTRACT In 3D echocardiography, the left ventricular (LV) longitudinal axis is often determined in end-diastole as a line perpendicular to the mid-point of the mitral valve plane pointing to the tip of the apex. It is assumed that the LV rotates around the longitudinal axis defined at end-diastole. However, it is a known fact that neither the mitral valve plane nor the apex are fixed during a cardiac cycle; accordingly, the longitudinal axis is dynamically moving in space rather than being motionless. Then, the following question arises: do we need not to consider the movement of the longitudinal axis for measurements, such as rotation and twist, with respect to the longitudinal axis? This study investigates how LV long-axis movement affects the rotation measurements and whether it is relevant in the analysis of 3D echocardiography data. To this end, two methods are examined. In Method 1, the configuration of the longitudinal axis is updated with the deformation of the LV, whereas in Method 2 the long axis configuration is fixed to its position at end-diastole during cardiac cycle. The comparison of two methods reveals a huge influence of the longitudinal axis translation on rotation measurements while the twist is not notably affected.

An Integrated Kinematic Calibration and Dynamic Identification Method With Only Static Measurements for Serial Robot

In this article, we propose an integrated calibration and identification method that can identify kinematic and dynamic parameters at the same time. Only a series of static experiments are required in this method, which can significantly simplify the experimental operation and improve the accuracy of identification. A novel calibration model based on axis configuration space and adjoint error model considering joint compliance with only position measurements is developed and both joint compliance and joint zero-offset errors are included in the proposed model. Identifiability analysis shows which joint compliance can be identified and the relationships between the identifiability of joint compliance and the number of measurement points. A recursive algorithm considering physical consistency is newly derived to obtain the derivatives of estimated inertial matrix and gravity vector with respect to joint twists. In this way, the coupling between kinematic and dynamic model is solved and the optimal kinematic and dynamic parameters can be derived using gradient-based optimizer. Comparative study with experiments are reported to show the effectiveness of our algorithm.

Studies of efficiency of the Kratta detectors in the deuteron breakup experiment.

An experiment focused on studies of relativistic effects in the proton-deuteron breakup reaction has been performed at Cyclotron Center Bronowice in Kraków, Poland with the use of the Kratta detectors. Thirty Kratta modules have been arranged in a planar symmetric around beam axis configuration at few selected polar angles at which significant relativistic effects have been predicted. In front of each Kratta module 4 thin plastic scintillators were installed acting as a fast timing detectors to improve a trigger system. Determination of acceptance and efficiency of the detectors is discussed.

Анализ опасности бокового оголения газопровода

This article presents the results of assessing the influence of the structural and technological parameters of the gas pipeline section (length, presence and height of soil above the pipe, operating pressure, temperature drop) on the value of the critical longitudinal compressive force determining its longitudinal stability at the initial rectilinear axis configuration. The article also discusses the features of the behavior of a section of a gas pipeline with a curved axis configuration during its operation and the conditions of longitudinal stability of such a section of the gas pipeline after the removal of soil along one of the lateral surfaces of the pipe, which caused its complete exposure.

Scalable production of large components by industrial robots and machine tools through segmentation.

The production of large components currently requires cost-intensive special machine tools with large workspaces. The corresponding process chains are usually sequential and hard to scale. Furthermore, large components are usually manufactured in small batches; consequently, the planning effort has a significant share in the manufacturing costs. This paper presents a novel approach for manufacturing large components by industrial robots and machine tools through segmented manufacturing. This leads to a decoupling of component size and necessary workspace and enables a new type of flexible and scalable manufacturing system. The presented solution is based on the automatic segmentation of the CAD model of the component into segments, which are provided with predefined connection elements. The proposed segmentation strategy divides the part into segments whose structural design is adapted to the capabilities (workspace, axis configuration, etc.) of the field components available on the shopfloor. The capabilities are provided by specific information models containing a self-description. The process planning step of each segment is automated by utilizing the similarity of the segments and the self-description of the corresponding field component. The result is a transformation of a batch size one production into an automated quasi-serial production of the segments. To generate the final component geometry, the individual segments are mounted and joined by robot-guided Direct Energy Deposition. The final surface finish is achieved by post-processing using a mobile machine tool coupled to the component. The entire approach is demonstrated along the process chain for manufacturing a forming tool.

Temperature dependence of the fluorescence lifetime and emission cross section of Tm:YLF in the 78–300 K range

We have investigated the spectroscopic properties of Tm:YLF material around 1900 nm in detail to understand its amplification performance at cryogenic temperatures. Fluorescence lifetime and emission cross section (ECS) measurements are performed in the 78–300 K range using crystals with Tm doping levels of 0.5 and 2.5%. The radiative lifetime of the 3F4 level of Tm:YLF is found to be temperature dependent, and has a value of around 18 ms at 78 K, and 15.25 ms at 300 K, respectively. The emission measurements indicate the presence of rather strong and reasonably broadband peaks even at cryogenic temperatures. The 1877 nm emission peak of the E//c configuration has a strength of around 2.4 × 10−20 cm2 and a full-width half maximum (FWHM) of around 4 nm at 100 K. The E//a axis configuration possesses a broader emission around 1908 nm with a FWHM of around 19 nm at 100 K, but with a lower peak ECS value of 0.75 × 10−20 cm2. We have also investigated the temperature variation of fluorescence lifetime for the 3H4 level, and the results showed that the two-for-one cross-relaxation process is also quite effective at cryogenic temperatures. These findings clearly demonstrate that cryogenic Tm:YLF systems have the potential to reach kW level average powers and sub-1-ps pulsewidths.

Reproducibility of exercise-induced premature ventricular beats predicts concealed non-ischemic left ventricular scar on cardiac magnetic resonance in athletes

Abstract Background Non-ischemic left ventricular scar (NLVS) at cardiac magnetic resonance (CMR) is a common substrate of apparently idiopathic premature ventricular beats (PVBs) in athletes. PVBs morphology, complexity and exercise-behavior are known predictors of NLVS. It remains to be established whether reproducibility of PVBs at exercise testing correlates with CMR findings. Purpose We aimed to evaluate the possible role of PVBs reproducibility at repeated exercise testing in predicting the presence of an underlying NLVS in athletes who underwent CMR for apparently idiopathic ventricular arrhythmias. Methods We included all consecutive competitive athletes referred to our center for the evidence of PVBs during pre-participation screening, who underwent two maximal exercise testings within one month (the first at the time of pre-participation screening, the second at the time of outpatient evaluation at our sports cardiology clinic). Exclusion criteria were known heart disease, family history of cardiomyopathy or channelopathy, abnormal ECG and echocardiography. We also excluded athletes with “common/usually benign” PVBs (non-exercise-induced infundibular or fascicular PVBs) as well as those on ongoing antiarrhythmic therapy. Reproducibility was defined as the presence of PVBs with same morphology and exercise-behavior in two subsequent tests. LGE on CMR was quantified with 5-SD method, using a threshold of 5% to define the presence of pathological LVNS. Results A total of 64 apparently healthy competitive athletes (86% males, mean age of 33±14 years old) were included. On CMR, NLVS was identified in 26 (41%). PVBs reproducibility criteria was met in 32 athletes (50%). A statistically significant difference in PVBs reproducibility was found between patients with and without LVNS [26 (100%) versus 6 (16%), p<0,001], irrespective of other factors such as age, sex, biventricular volumes and function (Figure 1). Among the 26 patients with NLVS, 18 (69%) showed PVBs with right-bundle branch block (R-BBB) with superior axis configuration, alone or associated with other morphologies. These arrhythmic patterns were confirmed by a second test in all cases. Among the 38 patients with normal CMR, the first exercise test showed R-BBB/superior axis PVBs, alone or associated with other morphologies, in 22 (57%); the second test confirmed such pattern in only 6 (16%), showing instead different morphologies in 8 (21%) and no PVBs in 24 (63%). Figure 2 represents an example of two cases included in the study. Conclusion In apparently healthy athletes who underwent CMR for “uncommon” PVBs, the presence of underlying LVNS was predicted by ventricular arrhythmia reproducibility. Specifically, reproducibility of PVBs with RBBB/superior axis morphology was highly predictive of a positive CMR. This finding may be very relevant for appropriate prescription of CMR in athletes with apparently idiopathic ventricular arrhythmias. Funding Acknowledgement Type of funding sources: None.

Availability Analysis of an Offshore Wind Turbine Subjected to Age-Based Preventive Maintenance by Petri Nets

This paper analyses the production availability and the associated maintenance costs of an offshore wind turbine with a horizontal axis configuration using Petri Nets modelling with Monte Carlo Simulation. For this purpose, different features are implemented: the reliability and maintainability characteristics of the components; the logistics of the production and maintenance operations, including different types of vessels, the mobilization time, costs and weather window. The maintenance strategies consist of corrective maintenance and age-based imperfect preventive maintenance that depends on the components’ age and age reduction ratio. Thereby, to increase the operating income and to reduce the costs associated with the operation and maintenance activities, the optimal parameters of the age-based preventive maintenance are estimated. As a case study, a generic offshore wind turbine that operates at the Viana do Castelo wind farm in Portugal is adopted. The wind farm is located 18 km off the shore. The turbine’s total exploration life is 25 years.

Particle control in long-pulse discharge using divertor pumping in LHD

Density control is crucial for maintaining stable confined plasma. Divertor pumping, where neutral particles are compressed and exhausted in the divertor region, was developed for this task for the Large Helical Device. In this study, neutral particle pressure, which is related to recycling, was systematically scanned in the magnetic configuration by changing the magnetic axis position. High neutral particle pressure and compression were obtained in the divertor for a high plasma electron density and the inner magnetic axis configuration. Density control using divertor pumping with gas puffing was applied to electron cyclotron heated plasma in the inner magnetic axis configuration, which provides high neutral particle compression and exhaust in the divertor. Stable plasma density and electron temperature were maintained with divertor pumping. A heat analysis shows that divertor pumping did not affect edge electron heat conductivity, but it led to low electron heat conductivity in the core caused by electron-internal-transport-barrier-like formation.

Optically detected spin–orbit torque ferromagnetic resonance in an in-plane magnetized ellipse

Time-resolved scanning Kerr microscopy has been used to perform optically detected, phase-resolved spin–orbit torque ferromagnetic resonance (SOT-FMR) measurements on a microscale CoFeB ellipse at the center of a Pt Hall cross subject to RF and DC current. Time-resolved polar Kerr images revealed localized dynamics with large amplitude at the center and weaker amplitude at the edges. Therefore, field swept SOT-FMR spectra were acquired from the so-called center mode to probe the SOTs active at the center of the ellipse, thus minimizing non-uniform edge contributions. When the magnetic field was applied at 30° from the hard axis of the ellipse and a DC current was applied, a marked asymmetry was observed in the amplitude and linewidth of the FMR peaks as the applied field was reversed. Both absorptive and dispersive parts of the spectra were in good agreement with a macrospin calculation. The damping parameter (α) and the Slonczewski torque parameter were determined to be 0.025 and (6.75 ± 0.75) × 10−7 Oe A−1 cm2, respectively. The hard axis SOT-FMR linewidth was found to be almost independent of the DC current value, suggesting that the SOT has a minimal influence in the hard axis configuration and that thermal effects were insignificant. This study paves the way for spatially resolved measurements of SOT probed using localized modes of microscale devices that go beyond the spatially averaged capability of electrical measurement techniques.

The effect of soft clay improvement using Prefabricated Vertical Drain (PVD) for rigid pavement structure

Rigid pavement is widely used in subgrade conditions that have low bearing capacity so that it will affect the life of the road plan and rigid pavement performance. Soil improvement that can be done is by using Prefabricated Vertical Drain (PVD). Soil consolidation with plate load test is carried out to get the modulus of subgrade reaction. Modulus of subgrade reaction without PVD is 2179,24 kN/m2/m and with PVD distance of 100 mm is 11311,09 kN/m2/m. The modulus of the verified subgrade reaction without PVD is 22419,21 kN/m2/m and with PVD is 38718,40 kN/m2/m. The thickness of the analyzed plates are respectively of 150 mm, 200 mm, 250 mm, 300 mm, and 350 mm. The position of the vehicle wheel load is in the middle, the end, and the edge. The deflections due to the position at the middle, the end, and the edge loads respectively for the entire plate thickness are reduced by an average value of 31%, 34%, and 33%. Rigid pavement performance based on the modulus of subgrade reaction and deflection caused by MST 10 ton vehicle loads with a 1.2 axis configuration shows that soil improvement using PVD can increase the modulus of subgrade reaction and reduce deflection values.

NpTrack: A n-Position Single Axis Solar Tracker Model for Optimized Energy Collection

The single axis solar tracker based on flat panels is used in large solar plants and in distribution-level photovoltaic systems. In order to achieve this, the solar tracking systems generally need to work by tracking the sun’s position with dozens, maybe hundreds of movements along the day with a maximal known tracking error within the specifications. A novel model is proposed along this work based on the control of the angle deviation within a (polar) single axis configuration. This way an optimization of the harnessing of solar energy can be achieved with as few panel displacements as possible in order to decrease the wear in the mechanical parts of the equipment and the energy consumed by it. This tracking approach was implemented with as few as seven positions along the day and got an estimated theoretical value of 99.27% of the total collected energy in a continuous tracking system. Regarding an annual average basis, it would be about 96.5% of a dual axis system according to the proposed model. The novelty of the model is related to a tradeoff between the gain with the simplicity of a single axis n-position tracking and the solar energy loss associated.

Predictors of Left Ventricular Scar Using Cardiac Magnetic Resonance in Athletes With Apparently Idiopathic Ventricular Arrhythmias.

BackgroundIn athletes with ventricular arrhythmias (VA) and otherwise unremarkable clinical findings, cardiac magnetic resonance (CMR) may reveal concealed pathological substrates. The aim of this multicenter study was to evaluate which VA characteristics predicted CMR abnormalities.Methods and ResultsWe enrolled 251 consecutive competitive athletes (74% males, median age 25 [17‐39] years) who underwent CMR for evaluation of VA. We included athletes with >100 premature ventricular beats/24 h or ≥1 repetitive VA (couplets, triplets, or nonsustained ventricular tachycardia) on 12‐lead 24‐hour ambulatory ECG monitoring and negative family history, ECG, and echocardiogram. Features of VA that were evaluated included number, morphology, repetitivity, and response to exercise testing. Left‐ventricular late gadolinium‐enhancement was documented by CMR in 28 (11%) athletes, mostly (n=25) with a subepicardial/midmyocardial stria pattern. On 24‐hour ECG monitoring, premature ventricular beats with multiple morphologies or with right‐bundle‐branch‐block and intermediate/superior axis configuration were documented in 25 (89%) athletes with versus 58 (26%) without late gadolinium‐enhancement (P<0.001). More than 3300 premature ventricular beats were recorded in 4 (14%) athletes with versus 117 (53%) without positive CMR (P<0.001). At exercise testing, nonsustained ventricular tachycardia occurred at peak of exercise in 8 (29%) athletes with late gadolinium‐enhancement (polymorphic in 6/8, 75%) versus 17 athletes (8%) without late gadolinium‐enhancement (P=0.002), (P<0.0001). At multivariable analysis, all 3 parameters independently correlated with CMR abnormalities.ConclusionsIn athletes with apparently idiopathic VA, simple characteristics such as number and morphology of premature ventricular beats on 12‐lead 24‐hour ambulatory ECG monitoring and response to exercise testing predicted the presence of concealed myocardial abnormalities on CMR. These findings may help cost‐effective CMR prescription.

Tailoring magnetism in self-intercalated Cr1+δTe2 epitaxial films

Magnetic transition metal dichalcogenide (TMD) films have recently emerged as promising candidates to host novel magnetic phases relevant to next-generation spintronic devices. However, systematic control of the magnetization orientation, or anisotropy, and its thermal stability, characterized by Curie temperature (Tc) remains to be achieved in such films. Here we present self-intercalated epitaxial Cr1+{\delta}Te2 films as a platform for achieving systematic/smooth magnetic tailoring in TMD films. Using a molecular beam epitaxy (MBE) based technique, we have realized epitaxial Cr1+{\delta}Te2 films with smoothly tunable over a wide range (0.33-0.82), while maintaining NiAs-type crystal structure. With increasing {\delta}, we found monotonic enhancement of Tc from 160 to 350 K, and the rotation of magnetic anisotropy from out-of-plane to in-plane easy axis configuration for fixed film thickness. Contributions from conventional dipolar and orbital moment terms are insufficient to explain the observed evolution of magnetic behavior with {\delta}. Instead, ab initio calculations suggest that the emergence of antiferromagnetic interactions with {\delta}, and its interplay with conventional ferromagnetism, may play a key role in the observed trends. To our knowledge, this constitutes the first demonstration of tunable Tc and magnetic anisotropy across room temperature in TMD films, and paves the way for engineering novel magnetic phases for spintronic applications.

Predictors of left ventricular scar at cardiac magnetic resonance in athletes with apparently idiopathic ventricular arrhythmias

Abstract Introduction In athletes with ventricular arrhythmias (VA) and otherwise unremarkable clinical findings, cardiac magnetic resonance (CMR) may reveal concealed pathological substrates. The aim of this multicentre study was to evaluate which VA characteristics were associated with CMR abnormalities. Methods We enrolled a consecutive series of 251 competitive athletes (74% males, mean age 28.5±14.5 years) who underwent CMR for evaluation of VA. We included athletes with &amp;gt;100 premature ventricular beats (PVBs)/24-hour or ≥1 repetitive VA (couplets, triplets or non-sustained ventricular tachycardia) on 12-lead 24-hour ambulatory ECG monitoring and negative family history, electrocardiogram and echocardiogram. Features of VA that were evaluated included number, morphology, repetitivity and response to exercise testing. Results Left-ventricular late gadolinium-enhancement (LGE) was documented in 28 (11%) athletes, mostly (N=25) with a subepicardial/midmyocardial (non-ischemic) distribution. On 24-hour ECG monitoring, PVBs with a right-bundle-branch-block and intermediate/superior axis configuration or multiple morphologies were documented in 24/28 (86%) athletes with versus 55/223 (25%) without LGE (p&amp;lt;0.001). More than 2000 PVBs were recorded in 6 (21%) athletes with versus 127 (57%) without positive CMR (p&amp;lt;0.001). At exercise testing, repetitive VA occurred at high work-load in 12 (43%) athletes with versus 26 (12%) without LGE (p&amp;lt;0.001). At multivariable analysis, all three VA features independently correlated with CMR abnormalities. Conclusions In athletes with apparently idiopathic VA, simple characteristics such as number and morphology of PVBs on 12-lead 24-hour ambulatory ECG monitoring and response to exercise testing predicted the presence of concealed myocardial abnormalities on CMR. These findings may help cost-effective CMR prescription. Flow chart Funding Acknowledgement Type of funding source: None

Machining process analysis for machine tool selection based on form-shaping motions

With the increase in machine tool types, including multi-axis control and multi-function machine tools, it can be difficult to select the appropriate machine tools for targeted parts machining. This study aims to automate machine tool selection by evaluating and comparing machining processes on a variety of machine tools. A system to analyze machining process based on the functional description of machine tools is developed as a first step. In the system, supposed machine tool structures are represented first corresponding to their form-shaping motions. Then, machining features are recognized using both CAD models of the workpiece and target shapes. The machining process consisting of a number of machining operations is analyzed using specific notations, and the operation expression matching the axis configuration is assigned to each recognized machining feature to decide the feasible machining operation. An enumerated machining operations list in the order of machining sequence is finally obtained as the machining process according to the machine tool structure. From a conducted case study, it is confirmed that the machining process analysis results could successfully support machine tool selection.

Numerical Modeling of a Darrieus Horizontal Axis Shallow-Water Turbine

AbstractFor decades, Darrieus turbines have shown their advantage over other turbines for providing hydropower. Most studies tend to be conducted with the turbine in its vertical axis configuration...

Isogeometric Optimal Design of Compliant Mechanisms Using Finite Deformation Curved Beam Built-Up Structures

Abstract This paper presents a configuration and sizing design optimization method for large deformation planar compliant mechanisms, using a continuum-based adjoint design sensitivity analysis (DSA) approach for built-up structures. Under the total Lagrangian formulation, the Jaumann strain formulation using the discretization of the global displacement field is employed to account for the finite deformation of arbitrarily curved Kirchhoff beams. In multipatch models, a rotational junction continuity condition is imposed using penalty and Lagrange multiplier methods. The developed adjoint DSA method can handle nonconservative loading conditions, which lead to asymmetry of tangent operator. Performance measures are displacements and rotation angles, and neutral axis configuration and cross-sectional thickness are considered as design variables. Also, analytical design sensitivity expressions for the rotation continuity condition are derived. Various compliant mechanisms including path-generators and an angular rotator are synthesized to demonstrate the applicability of the proposed method.

Ultra-short pulsed laser conditioning of metallic-bonded diamond grinding tools

A novel approach for machining of cylindrical ultra-hard materials with a highly defined contour is presented. Diamond grinding tools with complex geometry are manufactured with picosecond orthogonal and quasi-tangential laser ablation. Hitherto, laser manufacturing required a special axis configuration and optical beam deflection devices are utilized. Here, strategies and processes on a scanhead-free configuration using ultra-short pulsed laser are discussed enabling straight-forward implementation in industry. This rapid and flexible approach for the production of master tools for industrial grinding processes reveals benefits compared to conventional techniques. The manufacturing time is comparable to standard processes, however, increased grain protrusion is attained with the presented laser sharpening strategy. An ablation study for maximal material-removal rate reveals the impact of wavelength, strategy, and repetition rate at high average power up to 100 W. A combined laser manufacturing routine enables an ablation rate of 35 mm3 min−1 and a maximal geometric deviation of 3 μm after finishing. The final grinding tools are sharpened by a radial laser process preferentially removing the metal-based binding material. Hence, high-precision diamond grinding wheels with a mean error of smaller 1 μm over millimeter-sized contours can be manufactured. The meta-stable diamond structure persists and is assessed via Raman spectroscopy studies at laser cut grains.

漢字結構類型

Previously published analytical framework for the spatial configuration of Hanzi portrays Hanzi as having many complex spatial configurations, but fails to generate usefulness for the learning of Hanzi script, meaning or sound. Such framework has also been limited by being generated from only small sample size of simplified Chinese Hanzi. This paper present s a simple bi-axial analytical model, by which Hanzi’s spatial configuration can be dissected on the horizontal and vertical axis, into mono-partite or multipartite configurations on the horizo ntal axis, or single and multi-tiere configuration on the vertical axis. Each part can again be subdivided into tiers, and each tier into parts. The model is tested using Hanzi from standard and simplified Chinese Hanzi, Korean Hanja, Japanese Kanji, and Vietnamese chữ Nôm. The analysis shows that the model can be applied to all the script within the Hanzi region. The model is likely to generate useful insights as well as new approaches for the teaching of sound, script and meaning for Chinese Hanzi learning by improving the transpare ncy of Hanzi script, and pave the way to better script pronunciation transformation learning.