Orientation In Three-dimensional Space Research Articles

Transient Productivity Analysis and Completion Parameter Optimization of Perforating Herringbone Wells.

Herringbone wells are of great significance in tapping the potential of remaining reservoirs, improving recovery efficiency, and reducing development costs and have been widely used in oilfields, especially offshore oilfields. Due to the complex structure of herringbone wells, there is mutual interference between wellbores during seepage, resulting in complex seepage problems, and it is difficult to analyze the productivity and evaluate the perforating effect. In this paper, considering the mutual interference between branches and perforations, a prediction model of transient productivity of perforated herringbone wells was derived based on the theory of transient seepage, and the complex structure with any number of branches, arbitrary configurations, and orientations in three-dimensional space could be considered in this model. The formation pressure in reservoir points at different production times, IPR curves, and the radial inflow of herringbone well were studied by the line-source superposition method, which directly reflected the process of productivity and pressure change, avoiding the one-sidedness caused by using a point source to replace the line source in the stability analysis. Then, through the productivity calculation of different perforation schemes, the influence curves of perforation density, perforation length, perforation phase angle, and perforation radius on unstable productivity were obtained. Orthogonal tests were performed to obtain the degree of impact of each parameter on productivity. Lastly, the selective completion perforation technology was adopted. When the shot density at the end of the wellbore was increased, the productivity of herringbone wells could be improved economically and effectively. According to the above study, a scientific and reasonable construction scheme is recommended for oil well completion construction, which provides a theoretical basis for the improvement and development of perforation completion technology.

Clinical Evaluation of Balance in Children With Hemophilic Arthropathy.

Hemophilia is a hereditary coagulation disorder characterized by acute hemorrhages into the musculoskeletal system, leading eventually to arthropathy and disability. Chronic inflammation of the synovial membrane arises as a result of frequent joint hemorrhage. Proteolytic enzymes in the blood and cartilage cause deterioration after that, and joint space narrows. Chronic hemophilic arthropathy develops as a result of these unfavorable developments, which occur more quickly, especially in the target joints. Balance is a process that allows us to maintain our orientation in three-dimensional space while also regulating our body posture to avoid falling. After the central nervous system evaluates deep stimuli from sensory, visual, and auditory receptors, movement of the corresponding muscle groups is delivered. The goal of this study was to investigate how impairment to deep sensory receptors (proprioception) in the arthropathic joint structure affected hemophiliacs' balance. The study comprised 34 patients with hemophilic arthropathy, and 34 age and weight matched healthy volunteers. When balance tests of patients with hemophilic arthropathy were compared to healthy controls, hemophiliacs had a greater risk of falling. As the degree of arthropathy increased, so did the risk of falling and balance test values in individuals with hemophilic arthropathy. Treatment and coagulation factor prophylaxis to prevent the onset of arthropathy will improve patients' quality of life and reduce morbidity associated with frequent falls and bleeding. The online version contains supplementary material available at 10.1007/s12288-022-01526-0.

AUV position tracking and trajectory control based on fast-deployed deep reinforcement learning method

Aiming at the difficult problem of motion control of under-actuated and X-rudder autonomous underwater vehicle (AUV), the present work adopts deep reinforcement learning (DRL) method for its posture control. First, an AUV agent is trained with deep deterministic policy gradient (DDPG) algorithm in a simulation environment, and three-degree-of-freedom posture control of the AUV at a constant speed, fixed roll, variable pitch, and variable yaw, is successfully achieved. Subsequently, the AUV's yaw angle range is extended, and the control failure problem when AUV's yaw angle approaches a critical value is solved, realizing the rapid deployment of the DRL algorithm for AUV control. On this basis, the position-tracking task of AUV for targets in different orientations in three-dimensional space is completed, achieving a six-degree-of-freedom control of AUV. Additionally, by decomposing the trajectory control task of AUV in three-dimensional space into multiple position-tracking missions, the trajectory control of AUV in the underwater horizontal plane and underwater three-dimensional space is realized, demonstrating the significant task generalization ability of the control methods proposed.

Enhanced electromagnetic shielding property and anisotropic shielding behavior of corrugated carbon fiber felt composite and its sandwich structure

This work fabricated flat, corrugated, and corrugated sandwich short-chopped carbon fiber (SCF) felt/epoxy resin matrix composites for understanding the effect of fiber orientation in three-dimensional space on electromagnetic shielding property. Electromagnetic interference shielding effectiveness (EMI SE) in X band was experimentally investigated and electromagnetic simulation was carried out for investigating the surface current distribution. The results show that EMI SE of corrugated SCF felt composite decreases from 39.8 dB to 18.7 dB (@8.2 GHz) when the angle between transverse corrugated direction and field polarization direction increases from 0° to 90°, indicating obvious in-plane anisotropic shielding property. Corrugated sandwich SCF felt composite consisting of two flat and one corrugated felts has excellent EMI SE (>70 dB) in X band, which mainly results from multiple reflection in corrugated core. This kind of composite possesses good anti-compression ability and great deformability, demonstrating great potential in application of structural–functional integration and light-weight shielding composites.

A New Perspective on Low-Cost MEMS-Based AHRS Determination.

Attitude and heading reference system (AHRS) is the term used to describe a rigid body’s angular orientation in three-dimensional space. This paper describes an AHRS determination and control system developed for navigation systems by integrating gyroscopes, accelerometers, and magnetometers signals from low-cost MEMS-based sensors in a complementary adaptive Kalman filter. AHRS estimation based on the iterative Kalman filtering process is required to be initialized first. A new method for AHRS initialization is proposed to improve the accuracy of the initial attitude estimates. Attitude estimates derived from the initialization and iterative adaptive filtering processes are compared with the orientation obtained from a high-end reference system. The improvement in the accuracy of the initial orientation as significant as 45% is obtained from the proposed method as compared with other selected techniques. Additionally, the computational process is reduced by 96%.

Design and Implementation of a 3-Dimensional Attitudes Estimator Device using Low Cost Accelerometer & Gyroscope with Microcontroller IDE

Navigation and guidance systems for most automobile as well as aerospace applications require a coupled chip setup known as Inertial Measurement Units (IMU) which, depending on the degree of freedoms, contains a Gyroscope (for maintaining orientation and angular velocity), Accelerometers (to determine acceleration in the respective direction) and a Magnetometer (to determine the respective magnetic fields). In the three-dimensional space, any required rotation analysis is limited to the coordinate systems and all subtended angles in either direction must be defined by a fixed axis to effectively estimate the stability and to define all the attitude estimates needed to compile different rotations and orientations. The Quaternions are mathematical notations used for defining rotations and orientation in three-dimensional space. The simplest terms Quaternions are impossible to visualize in a three-dimensional space; the first three terms will be identical to the coordinate system, but through Quaternions another vector quantity is added into the equations, which may in fact underline how we can account for all rotational quantities. The fundamental analysis of these components different applications for various fields is proposed.

Average biometry of the cornea in a large population of Iranian school children.

This work establishes the average Scheimpflug corneal tomography for a population of 4953 healthy Iranian primary school children. These data were transformed to determine the corneal position and orientation in three-dimensional space, followed by a model fit that combines a biconic with a Zernike expansion. Girls were found to have slightly steeper corneas than boys. Both corneal surfaces show negative conic constants and significant higher-order aspheric Zernike terms. The corneal surfaces are decentered and misaligned with respect to each other and to the line of sight. Consequently, the average corneal surfaces may be considered as decentered and misaligned higher-order aspheres.

Гидроакустические закономерности пищевого поведения дельфинов

Гидроакустические закономерности пищевого поведения дельфинов определяются характеристиками и функциональностью их акустических сигналов. Все акустические сигналы дельфинов классифицированы в соответствии с их физическими характеристиками в свете теории сигналов и эхолокации следующим образом: последовательности ультракоротких сверхширокополосных когерентных импульсов — «щелчки», частотно-модулированные (ЧМ) симултоны с равномерно распределёнными тонами — «свисты», пачки взаимно когерентных импульсов (КИ), пачки взаимно некогерентных импульсов (НИ) и пачки универсальных импульсов (УИ). Они играют роль зондирующих сигналов шести сонаров дельфина, оптимизированных для решения разных эхолокационных задач. Возможности использования дельфинами различных акустических сигналов для эхолокационного поиска и классификации объектов питания изучены в настоящей работе на основе собственных и литературных данных. Последовательности «щелчков» дельфины могут применять для эхолокации объектов питания (отдельной рыбы ― на расстоянии до 70–110 м, косяка рыбы ― на расстоянии до 450–650 м) и сородичей (на расстоянии до 450–650 м), а также для их классификации. «Свисты» дельфины могут использовать для обнаружения объектов питания (отдельной рыбы ― на расстоянии до 2 км, косяка рыбы ― на расстоянии до 9–13 км) и сородичей (на расстоянии до 9–13 км), для определения их дальности, а также для измерения их относительной радиальной скорости (приближение или удаление). Дальность и точность эхолокационного обнаружения сородичей и объектов пищи сонаром дельфина с применением ЧМ-сигналов лучше, чем при использовании «щелчков», более чем на порядок. Кроме того, ЧМ-сонар обеспечивает измерение радиальной скорости приближения или удаления подводного объекта относительно дельфина. Между тем преимуществом сонара, использующего «щелчки», является тонкий анализ амплитудно-временных особенностей спектра эха рыб с целью их классификации. Пачки КИ дельфины могут применять для отслеживания динамики изменения положения объекта питания на дистанциях менее 2,5 м для точного захвата жертвы. Высокая разрешающая способность слуха дельфина по времени (около 0,02 мс) позволяет обрабатывать тонкую временную динамику эхосигналов, приходящих с малых расстояний. Пачки НИ ― сигналы разговорного языка ― дельфины могут использовать для организации различных видов сотрудничества и сложной кооперации между собой во время поиска и ловли рыбы. Пачки УИ дельфины могут применять для расширения пространства эхолокационного обзора вокруг особи, с целью улучшения качества мониторинга за объектами питания, независимо от положения головы дельфина в пространстве, для определения дальности и относительной радиальной скорости, а также для классификации объектов питания на малых расстояниях. Развитие и совершенствование разных типов акустических сигналов, сонаров и различных методов обработки эхосигналов у дельфинов вызвано, прежде всего, необходимостью оптимизации гидроакустических закономерностей их пищевого поведения и ориентации в трёхмерном пространстве. Можно предполагать наличие аналогичных гидроакустических закономерностей пищевого поведения у Odontoceti исходя из подобия их акустических сигналов и морфологии. Акустические закономерности пищевого поведения дельфинов и летучих мышей схожи несмотря на то, что у них различная среда обитания (водная и наземно-воздушная) и что эти млекопитающие относятся к разным отрядам царства животных (китообразные и рукокрылые).

On representing rotations by Rodrigues parameters in non-orthonormal reference systems.

A Rodrigues vector is a triplet of real numbers used for parameterizing rotations or orientations in three-dimensional space. Because of its properties (e.g. simplicity of fundamental regions for misorientations) this parameterization is frequently applied in analysis of orientation maps of polycrystalline materials. By conventional definition, the Rodrigues parameters are specified in orthonormal coordinate systems, whereas the bases of crystal lattices are generally non-orthogonal. Therefore, the definition of Rodrigues parameters is extended so they can be directly linked to non-Cartesian bases of a crystal. The new parameters are co- or contravariant components of vectors specified with respect to the same basis as atomic positions in a unit cell. The generalized formalism allows for redundant crystallographic axes. The formulas for rotation composition and the relationship to the rotation matrix are similar to those used in the Cartesian case, but they have a wider range of applicability: calculations can be performed with an arbitrary metric tensor of the crystal lattice. The parameterization in oblique coordinate frames of lattices is convenient for crystallographic applications because the generalized parameters are directly related to indices of rotation-invariant lattice directions and rotation-invariant lattice planes.

A novel method for correcting scanline-observational bias of discontinuity orientation.

Scanline observation is known to introduce an angular bias into the probability distribution of orientation in three-dimensional space. In this paper, numerical solutions expressing the functional relationship between the scanline-observational distribution (in one-dimensional space) and the inherent distribution (in three-dimensional space) are derived using probability theory and calculus under the independence hypothesis of dip direction and dip angle. Based on these solutions, a novel method for obtaining the inherent distribution (also for correcting the bias) is proposed, an approach which includes two procedures: 1) Correcting the cumulative probabilities of orientation according to the solutions, and 2) Determining the distribution of the corrected orientations using approximation methods such as the one-sample Kolmogorov-Smirnov test. The inherent distribution corrected by the proposed method can be used for discrete fracture network (DFN) modelling, which is applied to such areas as rockmass stability evaluation, rockmass permeability analysis, rockmass quality calculation and other related fields. To maximize the correction capacity of the proposed method, the observed sample size is suggested through effectiveness tests for different distribution types, dispersions and sample sizes. The performance of the proposed method and the comparison of its correction capacity with existing methods are illustrated with two case studies.

Rotation-invariant mean duration of strong ground motion

Strong-motion duration is usually computed separately for three components of recorded ground-motion time series. This results in different values of duration for the three components. Furthermore, the computed duration values are dependent on the sensor orientation. Physically, such dependence is not desirable. In this work, computing duration based on resultant recorded motion instead of individual components is proposed. Such a measure of duration is shown to be rotation-invariant and hence independent of the sensor axes. Furthermore, it is demonstrated that the duration of resultant motion represents the mean duration for all possible arbitrary sensor orientations in three-dimensional space. The results indicate that the apparent difference between duration of horizontal and vertical motion reported in the literature is not universal to all definitions of duration. A set of 462 three-component accelerograms from Europe and the Middle East is used to demonstrate and support the presented findings and arguments.

Features of Active Electrical States of Asymmetrical Dendrites of Brainstem Motoneurons during Generation of Stochastic Implulse Patterns: a Simulation Study

On models of motoneurons of the n. abducens nucleus with reconstructed dendritic arborizations having an active membrane, we investigated features of the relationships between passive transfer properties and dynamics of excitation states of asymmetrical dendrites during generation of complex periodical and stochastic impulse patterns (output neuronal codes). Various patterns were obtained by varying the intensity of tonic synaptic excitation homogeneously distributed over the dendrites. The electrical states of sites belonging to branches of the same dendrite or different dendrites were compared. For this comparison, branches were selected, which, according to the earlier performed cluster analysis, were assigned to the groups (electrotonic clusters) with a high and a low effectiveness of passive transfer of the somatopetal current. The selection took into account features of the dendritic structure of neurons of the exemined type. These were: (i) the presence of groups of the asymmetrical branches differing from each other according to their belonging to different clusters (high or low transfer effectiveness) in different dendrites, and (ii) the presence of branches belonging to different dendrites characterized by significantly different orientations in three-dimensional space of the brainstem within each electrical cluster. Comparative analysis showed that, in a given dendrite during generation of a complex periodical pattern, the asymmetrical branches belonging to high- or low-efficiency clusters were characterized by being in different states (high or low depolarization) in different phases of generation of repeated sequences of action potentials (APs). This relationship was consistent with those previously detected in neurons of other types and in other specimens of neurons of the above-mentioned type. During generation of such periodical spike patterns, the branches of different dendrites belonging to the same electrotonic cluster were in similar states. Similar relationships between the states of the branches of the same dendrite belonging to different clusters were also observed during generation of complex stochastic (non-periodical) impulse patterns. In the latter case, however, the essential feature was that the branches of different dendrites belonging to the same electrotonic cluster were often in opposite states. Thus, the number of combinations of discrete electrical states of asymmetrical parts of the dendritic arborization was much greater. Probably, it is precisely this circumstance that determined the quasi-stochastic nature of the output impulse pattern.

Assessment of tomographic PIV in wall-bounded turbulence using direct numerical simulation data

Simulations of tomographic particle image velocimetry (Tomo-PIV) are performed using direct numerical simulation data of a channel flow at Reynolds number of Reτ = 934, to investigate the influence of experimental parameters such as camera position, seeding density, interrogation volume size and spatial resolution. The simulations employ camera modelling, a Mie scattering illumination model, lens distortion effects and calibration to realistically model a tomographic experiment. Results are presented for camera position and orientation in three-dimensional space, to obtain an optimal reconstruction quality. Furthermore, a quantitative analysis is performed on the accuracy of first and second order flow statistics, at various voxel sizes normalised using the viscous inner length scale. This enables the result to be used as a general reference for wall-bounded turbulent experiments. In addition, a ratio relating seeding density and the interrogation volume size is proposed to obtain an optimal reference value that remains constant. This can be used to determine the required seeding density concentration for a certain interrogation volume size.

A method for estimating the orientation of a directional sound source from source directivity and multi-microphone recordings: Principles and application

Taking into account directivity of real sound sources makes it possible to try solving an interesting and biologically relevant problem: estimating the orientation in three-dimensional space of a directional sound source. The source, of known directivity, produces a broadband signal (in the ultrasonic range, in this application) that is recorded by microphones whose position with respect to source is known. An analytical method to process the recorded signals and estimate source orientation is developed in this paper. Experiments testing method performance in estimating source orientation were performed both in a laboratory environment with a Polaroid transducer as source and in a flight room with a Myotis daubentonii bat. In the first case, results showed the estimation method to be accurate and pointed out its limitations. The latter case is significant as an example biological application of the method for extracting behavioral features from bats; results are compared with alternative calculations based on microphone root-mean-square (rms)-pressure values.

Analysis of optimal and near-optimal continuous-thrust transfer problems in general circular orbit

A pair of practical problems in optimal continuous-thrust transfer in general circular orbit is analyzed within the context of analytic averaging for rapid computations leading to near-optimal solutions. The first problem addresses the minimum-time transfer between inclined circular orbits by proposing an analytic solution based on a split-sequence strategy in which the equatorial inclination and node controls are done separately by optimally selecting the intermediate orbit size at the sequence switch point that results in the minimum-time transfer. The consideration of the equatorial inclination and node state variables besides the orbital velocity variable is needed to further account for the important J 2 perturbation that precesses the orbit plane during the transfer, unlike the thrust-only case in which it is sufficient to consider the relative inclination and velocity variables thus reducing the dimensionality of the system equations. Further extensions of the split-sequence strategy with analytic J 2 effect are thus possible for equal computational ease. The second problem addresses the maximization of the equatorial inclination in fixed time by adopting a particular thrust-averaging scheme that controls only the inclination and velocity variables, leaving the node at the mercy of the J 2 precession, providing robust fast-converging codes that lead to efficient near-optimal solutions. Example transfers for both sets of problems are solved showing near-optimal features as far as transfer time is concerned, by directly comparing the solutions to “exact” purely numerical counterparts that rely on precision integration of the raw unaveraged system dynamics with continuously varying thrust vector orientation in three-dimensional space.

Structure and Dynamics of Human Apolipoprotein CIII

Human apolipoprotein CIII (apoCIII) is a surface component of chylomicrons, very low density lipoproteins, and high density lipoproteins. ApoCIII inhibits lipoprotein lipase as well as binding of lipoproteins to cell surface heparan sulfate proteoglycans and receptors. High levels of apoCIII are often correlated with elevated levels of blood lipids (hypertriglyceridemia). Here, we report the three-dimensional NMR structure and dynamics of human apo-CIII in complex with SDS micelles, mimicking its natural lipid-bound state. Thanks to residual dipolar coupling data, the first detailed view is obtained of the structure and dynamics of an intact apolipoprotein in its lipid-bound state. ApoCIII wraps around the micelle surface as a necklace of six approximately 10-residue amphipathic helices, which are curved and connected via semiflexible hinges. Three positively charged (Lys) residues line the polar faces of helices 1 and 2. Interestingly, their three-dimensional conformation is similar to that of the low density lipoprotein receptor binding motifs of apoE/B and the receptor-associated protein. At the C-terminal side of apoCIII, an array of negatively charged residues lines the polar faces of helices 4 and 5 and the adjacent flexible loop. Sequence comparison shows that this asymmetric charge distribution along the solvent-exposed face of apoCIII as well as other structural features are conserved among mammals. This structure provides a template for exploration of molecular mechanisms by which human apoCIII inhibits lipoprotein lipase and receptor binding.

Analysis of the orientation of primary cilia in growth plate cartilage: A mathematical method based on multiphoton microscopical images

The chondrocytic primary cilium has been hypothesized to act as a mechano-sensor, analogously to primary cilium of cells in epithelial tissues. We hypothesize that mechanical inputs during growth, sensed through the primary cilium, result in directed secretion of the extracellular matrix, thereby establishing tissue anisotropy in growth plate cartilage. The cilium, through its orientation in three-dimensional space, is hypothesized to transmit to the chondrocyte the preferential direction for matrix secretion. This paper reports on the application of classical mathematical methods to develop an algorithm that addresses the particular challenges relative to the assessment of the orientation of the primary cilium in growth plate cartilage, based on image analysis of optical sections visualized by multiphoton microscopy. Specimens are prepared by rapid cold precipitation-based fixation to minimize possible artifactual post-mortem alterations of ciliary orientation. The ciliary axoneme is localized by immunocytochemistry with antibody acetylated-α-tubulin. The method is applicable to investigation of ciliary orientation in different zones of the growth plate, under either normal or altered biomechanical environments. The methodology is highly flexible and adaptable to other connective tissues where tissue anisotropy and directed secretion of extracellular matrix components are hypothesized to depend on the tissue’s biomechanical environment during development and growth.

The haptic reproduction of orientations in three-dimensional space

This research studied the haptic perception of orientations in space rather than in a plane. It aimed at identifying the nature of the system of coordinate used to represent an orientation in space, when two parameters are necessary to code an orientation. Blindfolded participants inserted the tip of the index finger in a thimble mounted at the extremity of a haptic interface, explored the orientation of a "virtual rod" with to-and-fro movements and, after a short delay, reproduced the same orientation with the same fingertip in the absence of the virtual rod. Globally, the haptic reproduction of orientations was anisotropic. When the reproduction of orientations was carried out in the frontal plane, a classical oblique effect (lower performance for the diagonal orientations than for the vertical and horizontal orientations) occurred. When the reproduction of orientations was carried out in space, orientations seemed to be coded in a coordinate system based on the sagittal plane.

Modelling of magneto-mechanical behaviour of Ni–Mn–Ga single crytals

Reviews on the various models to describe the quasi-static magnetic-field-induced strains available in the literature are summarised. Two constitutive models, namely the Three-Segment model and Single Segment Model, are formulated aimed at predicting the quasi-static cyclic magnetic-field-induced strain under zero and non-zero stress bias. These two models provide reasonable correlation with experiments available in the literature. Some of the advantages of these two models are that they are in constitutive format, with low-order terms (second order) and hence are readily usable in the modelling of magneto-mechanical coupling effects such as in Finite Element formulations. The parameters of these two models are derived from the magnetisation and mechanical stress–strain behaviour of the material, and hence are readily obtainable from simple magnetisation and mechanical stress–strain tests. The magnetic-field-induced strain is then transformed into different orientations in three-dimensional space using strain tensors, based on certain assumptions, in order to apprehend the theoretical possibilities of magnetic-field-induced strain combinations in this material. It was shown that by varying the orientation of the twin-boundaries of the material, vast combinations of axial and shear magnetic-field-induced strains can be realised. The potential applications of this material are thus broadened dramatically.

Experimental investigation of three-dimensional flame-front structure in premixed turbulent combustion: II. Lean hydrogen/air Bunsen flames

Comprehensive laser measurements of three-dimensional flame-front structures for turbulent lean hydrogen/air premixed Bunsen flames are reported in this continuation paper. The local scalar front appears lamella-like for both the reaction progress variable and the OH mole fraction. This lamella-like feature cannot be predicted by the commonly accepted combustion-regime diagrams. The flame residence time relevant to the turbulent flames investigated here may be much smaller than the unstretched laminar value used for constructing these regime diagrams. Superadiabaticy and flame-front bulges convex toward the reactants are clearly observed, representing effects of the less-than-unity Lewis number of the mixture. The average size of flame bulges is found to increase with the turbulence integral length scale. Moderate positive correlations exist between the in-plane two-dimensional curvature and the three-dimensional progress-variable gradient. OH mole fraction is also correlated with the progress-variable gradient. Local flame orientation in three-dimensional space is close to an isotropic distribution, which is attributed to flame-surface wrinkling being strongly nonpassive. More backward-facing flame fronts are formed nearer the unburnt than the burnt side of the turbulent flame brush, suggesting the importance of large-scale flame-front bulges in turbulent flame propagation. Higher progress-variable dissipation rates are measured than for the unstretched laminar flame. By comparison with previously published data for turbulent hydrocarbon/air premixed flames, the present dissipation-rate measurements suggest that chemical reactions do not play an important role in the destruction or generation of progress-variable fluctuations. Discrepancies are observed even in the qualitative trends of some statistics of the progress-variable dissipation rate when compared with DNS data modeled with detailed chemistry.