Self-propelled System Research Articles

Light-guided actin polymerization drives directed motility in protocells.

Motility is a hallmark of life's dynamic processes, enabling cells to actively chase prey, repair wounds, and shape organs. Recreating these intricate behaviors using well-defined molecules remains a major challenge at the intersection of biology, physics, and molecular engineering. Although the polymerization force of the actin cytoskeleton is characterized as a primary driver of cell motility, recapitulating this process in protocellular systems has proven elusive. The difficulty lies in the daunting task of distilling key components from motile cells and integrating them into model membranes in a physiologically relevant manner. To address this, we developed a method to optically control actin polymerization with high spatiotemporal precision within cell-mimetic lipid vesicles known as giant unilamellar vesicles (GUVs). Within these active protocells, the reorganization of actin networks triggered outward membrane extensions as well as the unidirectional movement of GUVs at speeds of up to 0.43 µm/min, comparable to typical adherent mammalian cells. Notably, our findings reveal a synergistic interplay between branched and linear actin forms in promoting membrane protrusions, highlighting the cooperative nature of these cytoskeletal elements. This approach offers a powerful platform for unraveling the intricacies of cell migration, designing synthetic cells with active morphodynamics, and advancing bioengineering applications, such as self-propelled delivery systems and autonomous tissue-like materials.

Joint modeling of longitudinal and survival data for the evaluation of the impact of irrigation systems on the time until the occurrence of phoma leaf spot in Arabica coffee plants.

The coffee crop is prominent in Brazilian agriculture, making the country a global power in this area. One of the main concerns in the coffee sector is disease, which can affect coffee productivity and quality. Thus, it is important to evaluate the factors that may affect coffee quality and thus enhance the development of strategies to reduce coffee losses and costs and optimize production. This study evaluated the influence of the type of irrigation (self-propelled, drip, and center pivot) on the time until the occurrence of phoma leaf spot on Arabica coffee plants, considering the intensity of the disease. Additionally, the association between longitudinal incidence and the time until an event of interest was assessed based on the joint modeling of longitudinal and survival data. The results of this study identify the effectiveness of drip irrigation system compared with other systems; the use of such systems was associated with an ~46.5% reduction in the risk of leaf spot disease compared with the use of a self-propelled irrigation system. The use of a center pivot system increased the risk of disease progression compared with a self-propelled system. An association between the longitudinal and survival processes was also observed. The findings demonstrate the superior performance of the drip irrigation system in controlling phoma leaf spot disease in Arabica coffee plants compared with self-propelled and center pivot systems. This research highlights the potential of using drip irrigation to establish more effective agricultural practices in coffee cultivation, contributing to better disease management and improved crop quality. © 2024 Society of Chemical Industry.

Сombat operations model of a single self-propelled artillery system for the computer game ARMA 3

Military computer games are an important segment of the world media culture and media business. In addition to the entertainment aspect, military simulators play an important role in the training of future military specialists. However, quite often the scenario component of military gaming lags behind the rapid development of real military equipment. World experience of military conflicts of the 21st century shows that the most intensively developing segment of ground forces weapons is its artillery component. In this paper, a model of combat use of a new generation artillery system is developed. The model is intended for modification of the military game ARMA 3. The new generation artillery system is a large-caliber gun with a high level of automation. It has a high rate of fire, maneuverability, and shooting accuracy. Due to these qualities, the new generation artillery system is comparable in combat power to a unit of traditional guns and can carry out combat operations in single mode. A technique has been developed for dynamically assessing the current combat capability of an artillery system, taking into account the resource costs during fire activity, including indirect hits by the enemy. It is shown that in addition to traditional tactical counter-battery tasks, an artillery system can be used to destroy a suddenly emerging high-risk target. A high-risk target is a non-artillery system capable of causing very large damage in a short period of time. Based on the method of dynamically assessing the current combat capability, a tree of artillery system states is constructed. It includes the most probable states of the artillery system and the corresponding design parameters. A ratio is obtained that allows, for a known state of the artillery system, to estimate the number of shots needed to hit the target with the required guaranteed probability. Calculated examples show that a new-generation artillery system is capable of destroying a high-risk target, sometimes even at the cost of its own loss. The developed model is implemented and is being tested as a mod for the war game ARMA 3.

Power-law correlation in the homogeneous disordered state of anisotropically self-propelled systems

Self-propelled particles display unique collective phenomena, due to the intrinsic coupling of density and polarity. For instance, the giant number fluctuation appears in the orientationally ordered state, and the motility-induced phase separation appears in systems with repulsion. Effects of strong noise typically lead to a homogeneous disordered state, in which the coupling of density and polarity can still play a significant role. Here we study universal properties of the homogeneous disordered state in two-dimensional systems with uniaxially anisotropic self-propulsion. Using hydrodynamic arguments, we propose that the density correlation and polarity correlation generically exhibit power-law decay with distinct exponents (−2 and −4, respectively) through the coupling of density and polarity. Simulations of self-propelled lattice gas models indeed show the predicted power-law correlations, regardless of whether the interaction type is repulsion or alignment. Further, by mapping the model to a two-component boson system and employing non-Hermitian perturbation theory, we obtain the analytical expression for the structure factors, the Fourier transform of the correlation functions. This reveals that even the first order of the interaction strength induces the power-law correlations. Published by the American Physical Society 2024

Production Management of Self-Propelled Mortar Carrier System in Supporting Defense Industry Independence (Case Study PT. SAS Aero Sishan)

This research examines the production management of self-propelled mortar carrier systems in supporting the independence of Indonesia's defense industry. In accordance with the Law of the Republic of Indonesia No. 16 of 2012 on Defense Industry which aims to ensure that the fulfillment of defense and security equipment can be carried out independently. This research uses the theory of production and production management presented by E.L. Brech. The production system starts from inputs, which consist of information, management, equipment and workers, as well as raw materials and capital, which then get treatment in the form of transformation into outputs in the form of goods and services. This research uses a qualitative research method with a case study approach. Primary data is obtained through interviews and direct observation to related parties, while secondary data is obtained from literature studies, documents and other data. This research reveals that the production process at PT SAS Aero Sishan still requires improvement efforts to increase production effectiveness. This research underlines the importance of production management to optimize the resources owned through the production process so as to produce quality and superior products and services in order to realize the independence of the defense industry.

Induced Generalized Intuitionistic Fuzzy OWA Operator on GRA Method for Evaluation of Self-Propelled Artillery System: Ammunition Based Computer Assisted Military Experiment

The Self-Propelled Artillery System selection problem, which is a sub-problem of the Weapon Systems Selection Problems (WSSP), is an extremely important strategic level decision problem and constitutes the main focus of this study. To solve the problem, 3 different weapon systems were evaluated based on 7 criteria. The solution methodology consists of the integration of induced generalized ordered weighted averaging (IG-IFOWA) operator and Grey Relational Analysis (GRA). Such a solution proposal has not been seen in previous WSSP applications. To test the validity and applicability of the proposed methodology, the results of the study were tested on an ammunition-based computer-aided military experiment. The results reveal the effectiveness of the selected weapon system.

Collective motion of catalytic particles driven by abiotic aerobic metabolism

The phenomenon of collective motion of Pt particles (primary particles and aggregates) immersed in water containing organic fuels has been observed. Over time, these Pt particles tend to aggregate into numerous schools at the bottom of the container. Subsequently, unique spatiotemporal patterns emerge, including repetitive fission/fusion dynamics and dispersing/clustering synchronization among schools. Notably, the species of organic fuels influence the observed patterns. Pt particles exhibit self-propulsion through catalytic oxidation of organic fuels by dissolved oxygen, mirroring the chemical mechanism seen in living organisms. This contrast with previous studies on chemically propelled objects underscores the biomimetic nature of the system, highlighting its resemblance to living processes. This self-propelled system, operating with an aerobic metabolic mechanism, presents a valuable real-world model for elucidating the fundamental principles underlying collective motion in living organisms.

Study on the coupling calculation method for the launch dynamics of a self-propelled artillery multibody system considering engraving process

The launch dynamics theory for multibody systems emerges as an innovative and efficacious approach for the study of launch dynamics, capable of addressing the challenges of complex modeling, diminished computational efficiency, and imprecise analyses of system dynamic responses found in the dynamics research of intricate multi-rigid-flexible body systems, such as self-propelled artillery. This advancement aims to enhance the firing accuracy and launch safety of self-propelled artillery. Recognizing the shortfall of overlooking the band engraving process in existing theories, this study introduces a novel coupling calculation methodology for the launch dynamics of a self-propelled artillery multibody system. This method leverages the ABAQUS subroutine interface VUAMP to compute the dynamic response of the projectile and barrel during the launch process of large-caliber self-propelled artillery. Additionally, it examines the changes in projectile resistance and band deformation in relation to projectile motion throughout the band engraving process. Comparative analysis of the computational outcomes with experimental data evidences that the proposed method offers a more precise depiction of the launch process of self-propelled artillery, thereby enhancing the accuracy of launch dynamics calculations for self-propelled artillery.

Active Density Pattern Formation in Bacterial Binary Mixtures

Microbial communities often exhibit complex spatial structures that are important for their functioning, ecology, and evolution. While the role of biochemical interactions is extensively studied, how physical interactions contribute to structuring typically multispecies and phenotypically diverse bacterial communities is unclear. Here, we examined how motility, a major bacterial trait, affects the organization of model binary mixtures of motile and nonmotile bacteria, revealing a novel type of active self-organization. Motile bacteria induce large-scale, fluctuating density patterns in nonmotile bacteria across a wide range of physiologically relevant cell densities. Combining experiments and quantitative modeling, we demonstrate that this pattern formation solely results from physical interactions and relies on two key ingredients: By swimming in circles at surfaces, the motile bacteria generate recirculating hydrodynamic flows that advect nonmotile cells, and the breaking of vertical symmetry by gravity permits local density accumulation. The density patterns fluctuate as the advection landscape slowly rearrange with motile cells configurations on the surfaces. This new nonequilibrium mechanism for pattern formation in bacteria belongs to a different class compared to previous models for self-organization in self-propelled systems, which rely on localized traffic jamming in two dimensions. It is instead similar to fluctuation-dominated phase ordering in active nematics. The behavior also drives the formation of large scale and highly structured aggregates of nonmotile cells that express adhesins in the mixture, and it showcases how motile species activity can shape the spatial organization of complex microbial communities. Published by the American Physical Society 2024

Automated Bot For Shopping E-Cart

As we know shopping is very fascinating and alluring, at the same time it involves getting tired due to carry that heavy carts and stand in the long queues for billing our things. Again we have seen that sometimes an old age people, mothers or any other people who are physically disabled visiting shopping malls, grocery units, etc. where these people face a lot of problems regarding to carry their carts and select their products simultaneously. This bot will help and ease them in shopping by following automatically through human detecting sensors or line follower. Container with a propelling system that can be controlled remotely, and a sensor system to help to navigate the container. Self-propelled luggage system comprising a propelling system for driving at least one drive wheel associated with a container; user device via a wireless connection so that the robot follows the line.

Transient simulation and analysis of a supercritical CO2 heat removal system under different abnormal operation conditions

The supercritical carbon dioxide (sCO2) heat removal system, which is based on multiple closed Brayton cycles with sCO2 as the working fluid, is an innovative, self-propelling and modular heat removal system for existing and future nuclear power plants. Previous studies analysed its design, layout, control and operation. In addition, this study considers different sudden failures during the accident progress, e.g. failure of single sCO2 cycles, control systems and valves. These abnormal conditions were investigated with the thermal-hydraulic system code ATHLET for a generic Konvoi pressurized water reactor. In most cases, the failure of a single sCO2 cycle can be compensated. On the one hand, failure of the fans of the gas cooler leads to a pressure increase which may be mitigated by an inventory control system or cycle shutdown. On the other hand, unintended fan speed-up can cause compressor surge without adequate countermeasures. Furthermore, the system can operate under the cyclic blow-off from the steam generator safety valves when the relief valves are not available. Finally, the unintended closure of the valve which controls the steam flow through the compact heat exchanger triggers a fast cycle shutdown but a subsequent restart might be possible.

Flow-Driven Self-Propulsion of Oil Droplet on a Surfactant Solution Surface, as Observed by Time-Resolved Interfacial Tension and Surface Flow Speed Measurements.

The imbalanced force of the interfacial tension applied to an object has often been taken into account in the analysis of the motion mechanism of self-propelled systems. However, heterogeneous distributions of the interfacial tension also cause Marangoni flows, and these flows also contribute to the self-propulsion through the viscous force. The contribution of such flows has not been observed directly, while the interfacial tension difference has been measured in some systems. In this study, simultaneous measurements of the interfacial tension and surface flow speed of the unidirectional self-propelled motion of a butyl salicylate (BS) droplet in a circular channel on a sodium dodecyl sulfate (SDS) aqueous solution were achieved by the quasi-elastic laser scattering method. The droplet position was also recorded by observing its fluorescence excited by a UV light. The BS droplet speed dependence of the interfacial tension and surface flow speed were measured by varying the initial BS concentration codissolved in the SDS aqueous solution. As a result, a periodic decrease of the interfacial tension and a periodic increase of the speed of both forward and backward flows were observed when the droplet passed the sampling position of the time-resolved measurements. When they were converted to the distribution in space of the droplet position, no droplet speed dependence of the interfacial tension difference between the front and rear of the droplet was observed. On the other hand, the speed of both forward and backward flows increased as the droplet speed increased. By analysis of the above results with a simplified model, it was clarified that the forward flow driven by the interfacial tension gradient at the droplet front is actually important in the mechanism of the unidirectional self-propelled motion of a droplet.

ОПРЕДЕЛЕНИЕ СКОРОСТИ И ПРОИЗВОДИТЕЛЬНОСТИ АЭРОЗОЛЬНОЙ СТРУИ ДОЖДЕВАТЕЛЕЙ В КРУГОВЫХ САМОХОДНЫХ ДОЖДЕВАЛЬНЫХ УСТАНОВКАХ

Circular self-propelled sprinkler systems are highly efficient equipment for watering crops by sprinkling. Considering the diameter of irrigation, uniformity and productivity of the installation largely depend on the parameters and relative location of sprinklers on the main pipeline of the sprinkler machine, the assessment of the parameters of artificial rain for compliance with the set values for irrigation conditions requires appropriate theoretical and practical studies. (Research purpose) The research purpose is to theoretically calculate and experimentally confirm the results obtained characterizing the speed and performance of the aerosol jet at the outlet of the sprinkler in the fine sprinkling system, in relation to the main pipeline of the self-propelled sprinkler. (Materials and methods) The ballistic theory of the motion of droplets in the air in the Frene-Serre coordinate system perpendicular to the irrigation plane was used to construct a mathematical model of the motion of an aerosol jet. A set of sprinklers located on the main pipeline of a wide-scope circular sprinkler machine of the T-L Irrigation company was considered as an object of research. (Results and discussion) A mathematical model has been proposed for calculating the movement of an aerosol sprinkler jet in the air, which makes it possible to bring the volume flow rate of the sprinkler to an equivalent diameter and wetting depth in the irrigation plane. It has been shown that the data obtained make it possible to predict for a given set of sprinklers the depth of irrigation per unit of irrigated surface in the plane of the figure formed by two circles determined by the circular motion of two adjacent support trolleys of the machine. (Conclusions) It was determined that in order to bring the uniformity coefficient of circular sprinklers to a normalized value, when compiling appropriate mathematical models of the irrigation process, further adaptation of the movement of a single drop in the air to the parameters of artificial rain formed by the spray jet of the sprinkler is required.

Entropy by Neighbor Distance as a New Measure for Characterizing Spatiotemporal Orders in Microscopic Collective Systems.

Collective systems self-organize to form globally ordered spatiotemporal patterns. Finding appropriate measures to characterize the order in these patterns will contribute to our understanding of the principles of self-organization in all collective systems. Here we examine a new measure based on the entropy of the neighbor distance distributions in the characterization of collective patterns. We study three types of systems: a simulated self-propelled boid system, two active colloidal systems, and one centimeter-scale robotic swarm system. In all these systems, the new measure proves sensitive in revealing active phase transitions and in distinguishing steady states. We envision that the entropy by neighbor distance could be useful for characterizing biological swarms such as bird flocks and for designing robotic swarms.

Charge-Reduced Particles via Self-Propelled Electrohydrodynamic Atomization for Drug Delivery Applications.

Electrohydrodynamic atomization (EHDA) provides unparalleled control over the size and production rate of particles from solution. However, conventional methods produce highly charged particles that are not appropriate for inhalation drug delivery. We present a self-propelled EHDA system to address this challenge, a promising one-step platform for generating and delivering charge-reduced particles. Our approach uses a sharp electrode to produce ion wind, which reduces the cumulative charge in the particles and transports them to a target in front of the nozzle. We effectively controlled the morphologies of polymer products created from poly(vinylidene fluoride) (PVDF) at various concentrations. Our technique has also been proven safe for bioapplications, as evidenced by the delivery of PVDF particles onto breast cancer cells. The combination of simultaneous particle production and charge reduction, along with its direct delivery capability, makes the self-propelled EHDA a versatile technique for drug delivery applications.

Artillery and Drone Action Issues in the War in Ukraine

Abstract Technological developments in recent decades in multiple fields have revolutionised the actions of armed forces, as recently confirmed in the war in Ukraine where NATO countries’ artillery and missiles have undeniably outperformed the outdated spectrum of previous counter-insurgency actions, and the counter-battery fire of self-propelled weapons systems far exceeded the limits of the Iraq and Afghanistan theatres of operations, where such a response was easy to achieve because insurgent forces had no idea that such precise, coordinated and effective action was available at discovered targets. Drones have also become an inseparable part of military operations and have developed in an unprecedented way, being hardly detectable, precise, equipped with weaponry, radars, optoelectronic search means with sensors and modern communication and computer systems. Today, but especially in the future, the actions of drones and artillery means executing counter-battery fire will become indispensable in military operations to achieve desirable effects, and at the same time modern armies must have active and passive means of engagement and countermeasures against them to achieve effective force protection.

Armoring a liposome-integrated tissue factor with sacrificial CaCO3 to form potent self-propelled hemostats.

The development of hemostatic materials suitable for diverse emergency scenarios is of paramount significance, and there is growing interest in wound-site delivery of hemostasis-enhancing agents that can leverage the body's inherent mechanisms. Herein we report the design and performance of a biomimetic nanoparticle system enclosing tissue factor (TF), the most potent known blood coagulation trigger, which was reconstituted into liposomes and shielded by the liposome-templated CaCO3 mineralization. The mineral coatings, which mainly comprised water-soluble amorphous and vateritic phases, synergized with the lipidated TF to improve blood coagulation in vitro. These coatings served as sacrificial masks capable of releasing Ca2+ coagulation factors or propelling the TF-liposomes via acid-aided generation of CO2 bubbles while endowing them with high thermostability under dry conditions. In comparison to commercially available hemostatic particles, CaCO3 mineralized TF-liposomes yielded significantly shorter hemostasis times and less blood loss in vivo. When mixed with organic acids, the CO2-generating formulation further improved hemostasis by delivering TF-liposomes deep into actively bleeding wounds with good biocompatibility, as observed in a rat hepatic injury model. Therefore, the designed composite mimicry of coagulatory components exhibited strong hemostatic efficacy, which in combination with the propulsion mechanism would serve as a versatile approach to treating a variety of severe hemorrhages.

Hydrodynamics of a confined active Belousov-Zhabotinsky droplet.

Self-sustained locomotion of synthetic droplet swimmers has been of great interest due to their ability to mimic the behavior of biological swimmers. Here we harness the Belousov-Zhabotinsky (BZ) reaction to induce Marangoni stresses on the fluid-droplet interface and elucidate the spontaneous locomotion of active BZ droplets in a confined two-dimensional channel. Our approach employs the lattice Boltzmann method to simulate a coupled system of multiphase hydrodynamics and BZ-reaction kinetics. Our investigation reveals the mechanism underlying the propulsion of active BZ droplets, in terms of convective and diffusive fluxes and deformation of the droplets. Furthermore, we demonstrate that by manipulating the degree of confinement, strength, and nature of coupling between surface tension and active species' concentration, the motion of the BZ droplet can be directed. In addition, we are able to capture two different kinds of droplet behaviors, namely, sustained and stationary, and establish conditions for the sustained long-time motion. We envisage that our findings can be used not only to understand the mechanics of biological swimmers but also to design reaction-driven self-propelled systems for a variety of biomimetic applications.

Reentrant phase separation of a sparse collection of nonreciprocally aligning self-propelled disks.

We study a model of aligning self-propelled disks that nonreciprocally reorient the self-propulsion directions along the interparticle separation and towards the other disks. In the limit of small inertia and large softness, where conventional motility-induced phase separation is absent, we demonstrate that the homogeneous system at a small area fraction phase-separates into clusters and a low-density phase that, eventually, reenters the homogeneous phase with a monotonic increase in alignment strength. The disks inside the clusters move with a finite space-dependent speed, constantly shuttling between clusters through the surrounding low-density homogeneous phase while maintaining the hexatic structure properties within the clusters. The area fraction gradually increases from the periphery towards the center of the clusters with a negligible correlation of the velocity and propulsion direction inside the clusters. The novel collective behavior of reentrant phase separation is found to follow from both the limits of hard disks and extremely small inertia, tending towards the overdamped limit. However, important differences in the structural and dynamical properties are shown in the limit of hard disks and extremely small inertia, as compared to that for soft disks at finite inertia. We show that the cluster phase is associated with an effective temperature for a wide range of values of alignment strength, whereas an effective temperature is associated with the specific range of alignment in the low-density phase. We believe that the reentrant phase behavior in the limit of small area fraction and the remarkable properties of the clusters should be useful in understanding a wide range of physics issues, ranging from clogging and unclogging to information exchange and transport, in biological and synthetic self-propelled systems.

Chitosan enhanced the stability and antibiofilm activity of self-propelled Prussian blue micromotor

The emergence, spread and difficult removal of bacteria biofilm, represent an ever-increasing persistent infections and medical complications challenge worldwide. Herein, a self-propelled system Prussian blue micromotor (PB MMs) were constructed by gas-shearing technology for efficient degradation of biofilms by combining chemodynamic therapy (CDT) and photothermal therapy (PTT). With the interpenetrating network crosslinked by alginate, chitosan (CS) and metal ions as the substrate, PB was generated and embedded in the micromotor at the same time of crosslinking. The micromotors are more stable and could capture bacteria with the addition of CS. The micromotors show excellent performance, containing photothermal conversion, reactive oxygen species (ROS) generation and bubble produced by catalyzing Fenton reaction for motion, which served as therapeutic agent could chemically kill bacteria and physically destroy biofilm. This research work opens a new path of an innovative strategy to efficiently remove biofilm.