Motion Path Research Articles

Numeric Investigation of Non-Stationary Dust-Containing Airflow and Deposition of Dust Particles in the Lower Airways

Within creation of the mathematical model to describe the human respiratory system, we accomplished numeric investigation of non-stationary dust-containing airflow as well as dust particle deposition in the lower airways with the real anatomic geometry based on CT scans. Inhaled air is considered a multi-phase mixture of a homogenous gas and solid dust particles. Motion of a basic carrier gas phase is described using the Euler approach. Solid dust particles are a dispersed carried phase, which is described with the Lagrange approach. The k-ω model is used to describe turbulence. We consider non-stationary airflow during calm inhalation. The article presents calculated flow streamlines for the velocity of particles in inhaled air in the lower airways at different moments. We quantified a share of deposited particles (SDP) with various dispersed structure (between 10 nm and 100 µm) and density (1000 kg/m3, 2000 kg/m3, 2700 kg/m3) in the lower airways; the article provides computed motion paths of particulate matter. Solid particle deposition in the airways has different efficiency depending on particle sizes and density. SDP goes down as their sizes and masses decrease. Particle density mostly influences differences in deposition of micro-sized particles (2.5–20 µm): as particle mass and density grow, SDP in the airways also increases. SDP with their diameter being less than 1 µm amounts to approximately 20 % of all the particles that reach the inlet to the trachea. According to the results obtained by numeric modeling, the greatest share of dust particles penetrates the right main bronchus, predominantly the right middle and inferior lobar bronchi. Dust particles are able to induce diseases of the lungs, pneumoconiosis included.

A review: The formation, prevention, and remediation of acid mine drainage.

In abandoned open-pit coal mines, surface water and groundwater form acidic waters with high concentrations of metal ions due to chemical interactions with ores such as pyrite, and the formation of acid mine drainage (AMD) is one of the major sources of pollution of world concern. For this reason, this paper reviews the formation mechanisms and influencing factors of AMD. It also describes the prediction, prevention, and remediation techniques for AMD, identifying key research gaps. It also discusses the current challenges and shortcomings faced globally in the management of AMD. The formation of AMD is mainly caused by the oxidation of pyrite in mines, but it is mainly influenced by history, climate, topography, and hydrogeology, making the formation mechanism of AMD extremely complex. Currently, the remediation technologies for AMD mainly include active treatment and passive treatment, which can effectively neutralize acidic wastewater. However, the prediction technology for AMD is blank, and the source treatment technology such as passivation and microencapsulation only stays in the experimental stage. This leads to the high cost of treatment technologies at this stage and the inability to identify potential risks in mines. Overall, this review provides remediation tools for AMD from predicting root causes to treatment. Geophysical technology is an effective method for predicting the motion path and pollution surface of AMD in the future, and resource recovery for AMD is a key point that must be paid attention to in the future. Finally, integrated treatment technologies that deserve further exploration need to be emphasized.

Influence of Punch Servo Path on Elliptical Hole Flange Forming

This study investigated the process of forming an elliptical hole flange by using a SPFC780Y high-strength steel sheet with a material thickness of 1 mm. Three servo motion paths on a servo press were compared with a traditional crank motion path on a conventional press. Four punch motion paths were analyzed, namely a crank motion path on a conventional press (type T), a servo motion path with a 3-mm downward motion followed by a 0.5-mm upward motion (type S3), a servo motion path with a 2-mm downward motion followed by a 0.5-mm upward motion (type S2), and a servo motion path with a 1-mm downward motion followed by a 0.5-mm upward motion (type S1). The finished products of an elliptical hole flanging process were evaluated in terms of thickness, force-displacement, stress, strain, and springback. The results reveal that the products produced using the evaluated servo motion paths were superior to those produced using the evaluated crank motion path.

Subverting motion in science fiction? Beam in the Star Trek TV series

Abstract Characters in science fiction TV have to move through the universe at the speed which the plot necessitates. In Star Trek, characters can beam from one location to another in an instant. In the visual modality, there is no continuous path of motion between the source and the goal, which would technically disqualify beam from most linguistic definitions of motion. This study aims to map out the usage patterns of beam and investigate whether or not it is linguistically construed as motion within the show. The study is based on a section of the TV Corpus (Davies, Mark. 2019. The TV Corpus. https://www.english-corpora.org/tv/ (accessed 28 May 2022)) consisting of all available episodes of all Star Trek TV series between 1966 and 2005 and uses a combination of quantitative and qualitative methods. The study found that beam is indeed used as a motion verb within the series. Its usage is also quite varied, denoting motion of many different figures in many different directions. The fact that we conceive of beaming as motion even though there is no continuous path might be partly explained by the etymology of beam, and partly by the embodied nature of language. Our current register makes it is hard to imagine transportation without movement.

A hybrid modeling method for predicting the cutting force in whirlwind milling of lead screw

Analyzing the cutting force in the process of lead screw whirlwind milling can help us understand the processing quality and processability. Whirlwind milling is a process in which multiple cutting tools are driven by the cutter head to sequentially cut and process the workpiece. The cutting force changes periodically in the process of lead screw whirlwind milling. Analyzing the cutting force of the nth cutting needs to consider the influence of the previous n-1 cutting. This paper employed a hybrid method combining mathematical modeling and finite element analysis to predict the cutting force in lead screw whirlwind milling. Firstly, the tool motion path of lead screw whirlwind milling is analyzed by considering the influence of cutter inclination angle and relative tool-workpiece motion. The relationship between the nth tool path and the (n-1)th tool path is analyzed by considering the feed motion of the tool and the rotation motion of the workpiece. Furtherly, mathematical models of the nth tool path and the (n-1)th tool path are established. Then, based on the established mathematical models, the three-dimensional geometric model of the tool and workpiece is established by three-dimensional software. The establishment of the workpiece geometry model considers the influence of the previous n-1 cutting. The tool geometry model rotates along the (n-1)th cutting path, and the tool intersects the workpiece. Finally, the finite element model of lead screw whirlwind milling is established based on the above three-dimensional geometric model. The periodical cutting force in the lead screw whirlwind milling is obtained by simulating the nth cutting with the finite element model. The relevant lead screw whirlwind milling experiment was carried out to verify the reliability of the model prediction. The appropriate processing parameter range of lead screw whirlwind milling is obtained through the process parameter optimization.

Robotic manipulator motion planning method development using neural network-based intelligent system

The research relevance is determined by the constant development of industry and the use of robotic manipulators in production processes. The study aims to develop an approach to planning the trajectory of a manipulator robot using an intelligent system based on neural networks. An analysis method, as well as special methods such as design, machine learning, integration strategies, and optimisation techniques, were used to achieve this goal. The main results of the study cover a wide range of achievements in the development of methods for planning the motion of robotic manipulators and their integration into real production conditions. The analysis of existing methods for planning the motion of robotic manipulators and a review of intelligent control systems provided a comprehensive picture of the current state of the art. The developed methods of robot manipulator trajectory identified effective control strategies that consider both dynamic and static scenarios. Training a neural network to plan the optimal path of movement made it possible to detect, track and avoid obstacles in real-time. Hierarchical path planning, adaptive neural network control, genetic algorithms for path optimisation, and dynamic prediction for obstacle avoidance were used to integrate the developed methods into a real production environment. The optimisation and improvement of the created approaches have shown positive results in improving the safety and performance of robotic manipulators, reducing the risk of collisions, and avoiding damage to robots. In addition, the implementation of hierarchical trajectory planning and adaptive neural network control contributed to a significant increase in the accuracy and stability of manipulator movements in various production process scenarios. The practical significance of the study is to develop an intelligent control system and methods for planning the movement of robotic manipulators, which contributes to the efficiency and safety of their operation in real production conditions

Методика проектировочного расчета винтовых цилиндрических пружин сжатия

Helical cylindrical compression springs are most often used in the one-time actuation mechanisms in rocket and space applications as the push drives to perform useful work in moving detachable parts of the aerospace vehicles. Such drives possess maximum energy characteristics with minimal weight and cost. The paper proposes the pusher spring design calculation methodology making it possible to take into account the design values range determined by the given initial spring parameters, where the strength condition is satisfied. The calculation methodology takes into account the spring design values range and makes it possible to create an effective computational algorithm. It is introduced for a targeted and consistent search of satisfactory solutions in designing spring units and mechanisms with the required performance and reliability (dimensions, ability to overcome resistive forces along the motion path and move control objects to the required distance, as well as strength). Based on the computational algorithm, a software program was created for the design and verifying calculation of the helical cylindrical compression springs, which makes it possible to quickly find effective solutions to be introduced in the practical activities of designers and calculators.

Rendering Dynamic Source Motion in Surface Haptics via Wave Focusing.

Emerging surface haptic technologies can display localized haptic feedback anywhere on a touch surface by focusing mechanical waves generated via sparse arrays of actuators. However, rendering complex haptic scenes with such displays is challenging due to the infinite number of physical degrees of freedom intrinsic to such continuum mechanical systems. Here, we present computational focusing methods for rendering dynamic tactile sources. They can be applied to a variety of surface haptic devices and media, including those that exploit flexural waves in thin plates and solid waves in elastic media. We describe an efficient rendering technique based on time-reversal of waves emitted from a moving source and motion path discretization. We combine these with intensity regularization methods that reduce focusing artifacts, improve power output, and increase dynamic range. We demonstrate the utility of this approach in experiments with a surface display that uses elastic wave focusing to render dynamic sources, achieving millimeter-scale resolution in experiments. Results of a behavioral experiment show that participants could readily feel and interpret rendered source motion, attaining 99% accuracy across a wide range of motion speeds.

Understanding Elephant Movement Paths in a Fragmented Corridor Using Animal Energetics

Understanding Elephant Movement Paths in a Fragmented Corridor Using Animal Energetics

Evacuation System as a Route Guide on Signage at Jakarta International Stadium

Stadiums with large capacity and high-rise buildings must be supported by architecture and information systems that can be presented in the form of signage. This study aims to describe the meaning of signage so that the path of movement has a sequence of evacuation routes in a fast, precise, and safe direction. Environment Graphics Design (EGD) is a solution for signage as a route guide for football spectators when disasters and emergencies occur. The analysis carried out is an evaluation of data and fact findings with literature on EGD theory, then conclusions are drawn. The evacuation system on signage, namely evacuation maps, exit signs, and assembly point signs, has a signage category as regulatory. The regulation follows the standard concerning Building Amenity Requirements and refers to OSH signage. Evacuation maps have signage categories as identification and directional, exit signs have signage categories as directional and warning, and assembly point signs have signage categories as identification and warning. The dominant visual and placement on signage are the exit signs, while the placement on the assembly point signs refers to the regulations as a refuge area. There are no evacuation maps around the emergency exit so football spectators who are not familiar with the stadium.

Effect of pores on microscopic wear properties and deformation behavior of Ni-Cr alloy coating.

Molecular dynamics (MD) was carried out to simulate the friction behavior of Ni-Cr alloy coating containing pores. The mechanical properties, displacement, abrasion depth, and defect change patterns of the coating under nano-friction were studied. It was found that the stacking fault would extend to the pores, and both tangential and normal forces decreased when the grinding ball was above the pores. Meanwhile, the pores changed the extension direction of shear strain inside the coating, and stress concentrations were generated at the pores. In addition, the deformation behavior inside the coating was influenced by the processing depth, the smaller the relative height of the grinding ball and the pore, the greater the atomic deformation around the pore. The pores changed the path of atomic movement, resulting in less deformation of the coating below the pores. The presence of pores promoted the generation of surface steps and increased the amount of wear on the coating. It was also found that pores facilitated energy release and provided space for dislocation extension, and the large accumulation of dislocations led to frictional strengthening near the pores, which enhanced the properties of the material below the pores. It was found that the increase of the pore size caused the normal force decrease and the wear performance of the coating decrease, but the thermal insulation performance would be improved. In this paper, nanoscale modeling was performed in the large-scale atomic/molecular parallel simulator (LAMMPS) simulation environment. The model was visualized and analyzed in three dimensions by Open Visualization Tool (OVITO), the common neighbor analysis (CNA) method was used to obtain the atomic structure information, and the dislocation analysis (DXA) method was applied to obtain the dislocations.

Features of the geological structure of the Achimov complex of the Yarudeisky megaswell (Western Siberia)

This work is devoted to the peculiarities of sedimentation and geological structure of clinoform deposits of the Yarudeisky megaswell (Western Siberia). The main feature of the clinoforms under consideration is that the sediments are confined to the marginal regional clinocyclite of the western dip of the area of oncoming clinoforms, formed in relatively shallow sea conditions and differing from deep-sea clinoforms by pinching out not onto the Bazhenov formation or the early underlying clinoforms of the western dip, but by stopping their spread along the path of movement of the oncoming clinoforms eastern dip. The study of the counter clinoforms of the Yarudeisky megaswell is based on a regional analysis of the structure of cross-layered deposits in conditions of extremely poor knowledge of the study area. Within the framework of western dipping clinoforms, possible oil and gas potential prospects for the Achimov complex within the boundaries of the Yarudeisky megaswell are identified. As a result of the analysis of geological and geophysical data, the boundaries of the distribution of opposing clinoform complexes in the study area were determined. The existing paleo-geomorphological conditions that contribute to the accumulation of sandstone with improved properties in the designated seismic complexes are presented. The fields of the Nadym oil and gas bearing region with the proven productivity of the Neocomian clinoform complex are indicated, which confirms the oil and gas potential of the region and suggests favorable conditions for the accumulation of hydrocarbons in the study area.

Stoneley waves in isotropic crustal rocks under the theory of generalized thermoelastic diffusion

This paper investigates the propagation of Stoneley waves through bonded and unbonded interfaces between two dissimilar homogeneous transversely isotropic generalized thermo-elastic diffusion rocks. The governing equations for the current problem are obtained and are solved to determine the characteristic polynomial equations for both mediums in terms of penetration depth. These equations are solved using Ferrari’s approach, and the variation in penetration depths with angular frequency and wavenumber is shown. The secular equations of the Stoneley waves are developed using proper boundary conditions and these equations have been solved numerically to determine the phase velocity and attenuation coefficients. We have discovered three modes of the Stoneley waves in thermo-diffusive crustal rocks. We have confirmed that the paths of particle motion for Stoneley waves are elliptic in nature. Some known results [Kumar et al. [2017] “Mathematical modeling of Stoneley wave in a transversely isotropic thermoelastic media”, Applications and Applied Mathematics 12(1), 319–336; Kumar and Kansal [2008b] “Propagation of Rayleigh waves on free surface of transversely isotropic generalized thermoelastic diffusion”, Applied Mathematics and Mechanics29(11), 1451–1462] are recovered from this analysis to validate our investigation.

A review of magnetically driven swimming microrobots: Material selection, structure design, control method, and applications

Abstract Magnetically driven swimming microrobot is a typical one in the family of microrobots and they can achieve navigation and manipulation in low Reynolds number biomedical environments with an external magnetic drive strategy. This study reviews recent advances in material selection, structure design, fabrication techniques, drive control method, and applications for magnetically driven swimming microrobots. First, the materials used in magnetically driven swimming microrobots were introduced and the effect of material selection on performance was discussed. Second, structure design of swimming microrobots and manufacturing techniques are reviewed, followed by a discussion on the main advances in effective motion control, path planning, and path tracking. Then, the multi-applications of magnetically driven swimming microrobots including targeted drug delivery, cell manipulation, and minimally invasive surgery are summarized. Finally, the current challenges and future directions of the work on magnetically driven swimming microrobots are discussed.

Stationary local random countable sets over the Wiener noise

The times of Brownian local minima, maxima and their union are three distinct examples of local, stationary, dense, random countable sets associated with classical Wiener noise. Being local means, roughly, determined by the local behavior of the sample paths of the Brownian motion, and stationary means invariant relative to the Lévy shifts of the sample paths. We answer to the affirmative Tsirelson’s question, whether or not there are any others, and develop some general theory for such sets. An extra ingredient to their structure, that of an honest indexation, leads to a splitting result that is akin to the Wiener–Hopf factorization of the Brownian motion at the minimum (or maximum) and has the latter as a special case. Sets admitting an honest indexation are moreover shown to have the property that no stopping time belongs to them with positive probability. They are also minimal: they do not have any non-empty proper local stationary subsets. Random sets, of the kind studied in this paper, honestly indexed or otherwise, give rise to nonclassical one-dimensional noises, generalizing the noise of splitting. Some properties of these noises and the inter-relations between them are investigated. In particular, subsets are connected to subnoises.

Enhanced Clustering and Indoor Movement Path Generation from Wi-Fi Fingerprint Data Using Bounding Boxes and Grid Cells

Recently, various application fields utilizing Wi-Fi fingerprint data have been under research. However, fingerprint data collected from a specific location does not include relevant information, such as continuity. Therefore, most indoor positioning technologies predict the user’s location based on location signals collected at specific points within the indoor space, without taking into account the user’s movements. Hence, there is a need for technology that improves the accuracy of indoor positioning while moving. This paper proposes a technique to generate movement path data by applying the concepts of “BB” and “Grid Cell” from computer vision to Wi-Fi fingerprint data. This approach represents data points as bounding boxes (BBs), then establishes grid cells and clusters of these BBs to generate adjacency information. Subsequently, movement path data are created based on this information. We utilized the movement path information generated from the dataset as training data for machine learning and introduced an enhanced indoor positioning technology. First, the experiments in this paper assessed the performance of the proposed technology based on the number of paths in the LSTM model. Second, the performance of clustering methods was compared through experiments. Finally, we evaluated the performance of various machine learning models. The experimental results confirmed a maximum accuracy of 94.48% when determining the location based on route information. Clustering performance improved accuracy by up to 3%. In comparative experiments with machine learning models, accuracy improved by up to 2.8%.

Stability and performance benefits of system tautochrones for vibration control

Centrifugal pendulum vibration absorbers have become a prominent means of controlling torsional oscillations that are typically generated by the combustion pulses within an internal combustion engine. The dynamic stability and performance of devices designed to smooth torsional oscillation are highly dependent upon the motion path defined for their pendulous masses. Generally speaking, dynamic responses are more difficult to manage when pendulum and system resonances shift as a function of the excitation levels due to nonlinear effects. As a result, paths for pendulums that are so-called tautochronic, meaning their resonance does not change as the pendulum amplitude varies, facilitate designing vibration absorbing systems that efficiently reduce vibration even as excitation levels increase. Approximate tautochronic paths for centrifugal pendulum vibration absorbers (CPVAs) are typically derived by making simplifying assumptions, which uncouple the pendulum dynamics from that of the rotor (base) system in which it acts upon. The resulting family of motion paths enable absorber designs that generate desirable and reliable vibration absorption, when slightly over-tuned with respect to the excitation frequency. In this paper, we begin the process of relaxing the assumptions that isolate a pendulum subsystem from its operating context by considering the complete system, which consists of a pendulum with inertial-coupling to the base system. For a simplified vibration system related to a CPVA, wherein a base mass rolls on a horizontal plane and a pendulous mass slides within a cut-out on the sliding base mass, we identify shapes of cut-outs that produce system brachistochrone curves. As in the case of a classical brachistochrone for a fixed base mass, we show the system brachistochrone is a system tautochrone, meaning for a range of input energy, system response that includes pendulum and base mass motions together have a constant period. We show that system tautochrones have distinct vibration control advantages, including superior dynamic stability and vibration absorbing performance. Our results provide a guide to how one can find solutions for the analogous CPVA system.

Quadruped Rotary Galloping Gait Pattern within a Constant Radius Bend Using Accelerometry

This paper provides an initial investigation of quadruped rotary galloping gait patterns using data from racing greyhounds as they navigate their way around a constant radius bend. This study reviewed actual race data collected over a five month period from 2986 racing greyhounds. Using numerical dynamics modelling and value range analysis important factors were identified and analysed. By cleaning and synthesising simple X and Y data and also processing data for accuracy greyhound motion path dynamics results were produced for analysis. The results show that the galloping path greyhounds took going into the bend was different from the path coming out of the bend. It also shows that more than 50% of the greyhounds naturally optimised their path for a longer transition while minimising jerk when entering and exiting the bend. This research verified that individual greyhounds naturally chose different path transition lengths for accommodating their dynamic conditions. Finally, it was found that the greyhound galloping path dynamics state is less intense during the second half of the bend.

Development of the algorithm for the movement of the measuring module of the system of automated non-destructive testing of the nozzle of a lpre

The paper considers the development of the algorithm for the movement of the measuring module of the system of automated non-destructive testing of solder joints of the nozzle of a liquid propellant rocket engine (LPRE). The object of control, the flaws in soldered joints that arise during the manufacturing process, as well as the problems of production and testing of assembly units, are described. The main factors that reduce the probability of detecting defects are determined, and solutions are proposed. The necessity of using route construction algorithms in the developed traffic algorithm is substantiated. An algorithm for obtaining the path of the transducer movement for the measuring module of the system of automated non-destructive testing of solder joints is defined to detect such defects as "dry joint", "cold lap" and "partial dry joint".

A Study on Avalanche-Triggering Factors and Activity Characteristics in Aerxiangou, West Tianshan Mountains, China

Through analyzing the triggering factors and activity characteristics of avalanches in Aerxiangou in the Western Tianshan Mountains, the formation and disaster-causing process of avalanches were studied to provide theoretical support and a scientific basis for avalanche disaster prevention. In this paper, based on remote sensing interpretation and field investigation, a spatial distribution map of avalanches was established, and the induced and triggering factors in disaster-prone environments were analyzed using the certainty factor model. The degree of influence (E) of the disaster-causing factors on avalanche triggering was quantified, and the main control conditions conducive to avalanche occurrence in different periods were obtained. The RAMMS-avalanche model was used to analyze the activity characteristics at points where multiple avalanches occurred. Research results: (1) The E values of the average temperature, average snowfall, and surface roughness in February were significantly higher than those of other hazard-causing factors, reaching 1.83 and 1.71, respectively, indicating strong control. The E values of the surface cutting degree, average temperature, and average snow depth in March were all higher than 1.8, indicating that these control factors were more prominent than the other factors. In contrast, there were four hazard-causing factors with E values higher than 1.5 in April: the mean temperature, slope, surface roughness, and mean wind speed, with clear control. (2) Under the influence of the different hazard-causing factors, the types of avalanches from February–April mainly included new full-layer avalanches, surface avalanches, and full-layer wet avalanches. (3) In the RAMMS-avalanche simulation test, considering the deposition effect, compared to the previous avalanche movement path, the secondary avalanche flow accumulation area impact range changes were slight, while the movement area within the avalanche path changes was large, as were the different categories of avalanches and their different movement characteristic values. Overall, wet snow avalanches are more hazardous, and the impact force is larger. The new snow avalanches start in a short period, the sliding rate is fast, and the avalanche sliding surface (full-snow surface and face-snow) of the difference is mainly manifested in the differences in the value of the flow height.