Track Assembly Research Articles

Experimental study on reinforcement of bionic grouser of deep-sea mining vehicle

To fulfill the operational demands of deep-sea tracked mining vehicles traversing soft seabed substrates, an evaluation of the characteristics of these substrates was conducted, drawing a comparison with the land swamp black soil found in the buffalo's habitat. Employing the principles of biomimicry, two distinct types of bionic grouser were devised, replicating the configuration of the buffalo's hooves in both the horizontal and vertical planes. Utilizing self-constructed testing platforms, exhaustive examinations of the reinforcement efficacy of these bionic track grousers were undertaken, spanning from single-grouser to multi-grouser configurations and encompassing the entire track assembly. The findings unequivocally demonstrate a pronounced and consistent enhancement in traction force for both types of bionic grousers. Notably, the W-shaped bionic grouser, mimicking the horizontal contour of the buffalo's hoof, exhibits the most substantial increase in traction force. The maximum enhancement in traction force for individual bionic grouser exceeds 30%, while the overall track achieves an increase of over 19%. This research provides a valuable reference and establishes a foundational framework for the design of equipment tailored for the locomotion of deep-sea tracked mining vehicles across soft substrates.

Impact of hydrocarbon exposure on the mechanical properties of rail pads

This study investigates the effect of hydrocarbon exposure on the mechanical behaviour of seat pads used as a part of the fastening system in rail transport. Three different types of rail pads are examined, two made of EPDM (Ethylene Propylene Diene Monomer) and one made of EVA (Ethylene Vinyl Acetate). The results indicate that hydrocarbon exposure has a significant effect on the dynamic stiffness and mass stability of the pads, particularly in the EPDM ones. More specifically, it is observed that EPDM exposure to hydrocarbons increases the flexibility of the pads. Furthermore, for prolonged exposure periods (500 hours), this flexibility can become so pronounced that exhausts the pad's ability to deform under the loads applied during track assembly, which results in a more rigid behaviour than aging. Such findings are important as they suggest that hydrocarbons can negatively impact the performance and safety of rail transport due to the changes induced in critical mechanical properties of pads. Consequently, measures should be taken by contractors and infrastructure managers to reduce the adverse influence of hydrocarbons on rail pads, which contributes to increase the safety and efficiency of rail transport.

Fluorescent human RPA to track assembly dynamics on DNA

DNA metabolic processes including replication, repair, recombination, and telomere maintenance occur on single-stranded DNA (ssDNA). In each of these complex processes, dozens of proteins function together on the ssDNA template. However, when double-stranded DNA is unwound, the transiently open ssDNA is protected and coated by the high affinity heterotrimeric ssDNA binding Replication Protein A (RPA). Almost all downstream DNA processes must first remodel/remove RPA or function alongside to access the ssDNA occluded under RPA. Formation of RPA-ssDNA complexes trigger the DNA damage checkpoint response and is a key step in activating most DNA repair and recombination pathways. Thus, in addition to protecting the exposed ssDNA, RPA functions as a gatekeeper to define functional specificity in DNA maintenance and genomic integrity. RPA achieves functional dexterity through a multi-domain architecture utilizing several DNA binding and protein-interaction domains connected by flexible linkers. This flexible and modular architecture enables RPA to adopt a myriad of configurations tailored for specific DNA metabolic roles. To experimentally capture the dynamics of the domains of RPA upon binding to ssDNA and interacting proteins we here describe the generation of active site-specific fluorescent versions of human RPA (RPA) using 4-azido-L-phenylalanine (4AZP) incorporation and click chemistry. This approach can also be applied to site-specific modifications of other multi-domain proteins. Fluorescence-enhancement through non-canonical amino acids (FEncAA) and Förster Resonance Energy Transfer (FRET) assays for measuring dynamics of RPA on DNA are also described. The fluorescent human RPA described here will enable high-resolution structure-function analysis of RPA-ssDNA interactions.

A verification-oriented and part-focused assembly monitoring system based on multi-layered digital twin

In line with the human centricity characteristics of the emerging Industry 5.0 paradigm, manual assembly has long been an indispensable element of the small-batch and customized products. Nevertheless, the flexibility of manual operations is prone to assembly errors caused by human uncertainties. Since the newly assembled part directly determines the quality of products, the part-focused verification method has been widely adopted for manual assembly assistance. However, a part is partial to the whole assembly and occluded by other parts, which makes verification difficult. By leveraging the digital twin (DT) technology, one can construct a physical twin (PT) scene to represent the on-site assembly and a DT scene to represent the assembly’s theoretical status in real time. Only if the part is assembled correctly, the newly assembled part can be mapped to the corresponding DT part model. Otherwise, the difference between the PT and the DT part can indicate a potential assembly error. Based on this idea, this paper proposes a verification-oriented and part-focused monitoring system based on multi-layered digital twin for manual assembly assistance. A multi-layered DT framework is constructed to build the geometric and logical connection between the physical and digital space. With the synchronization of DT, the newly assembled part and its corresponding template are generated using a point cloud reservation algorithm, and a two-direction matching algorithm is adapted to evaluate whether the newly assembled part is in the expected position for verification. The proposed monitoring system only requires one shot of the assembly scene in movable view for verification, which meets the flexible requirement for manual assistance in human-centric assembly. The experimental result shows that the proposed monitoring system can detect potential part errors and track assembly process information after manual assembly work, which is significant for human-centric intelligent manufacturing system development.

Modeling and Verification of Rolling Resistance Torque of High-Speed Rubber Track Assembly Considering Hysteresis Loss

Due to the viscoelasticity of rubber materials, hysteresis loss due to deformation is the main reason for the rolling resistance of high-speed rubber tracks. Since the structure and material of high-speed rubber track assemblies are different from traditional tires and metal tracks, the rolling resistance theory of traditional wheeled and tracked vehicles is not applicable. Therefore, in order to determine the rolling resistance scientifically and accurately, the mechanism research of the rolling resistance of high-speed rubber track assembly is the key to the design of high-speed rubber crawler vehicles. In this paper, the stress-strain characteristics of rubber track under the action of compression, tension, bending, and driving were studied. The strain load spectrum of rubber tracks was established, and the strain cyclic load was extracted by the rainflow method. The temperature model of the rubber track was developed based on its dynamic characteristics. On the basis of energy conservation, the hysteresis loss of rubber is equivalent to the energy consumption of rolling resistance, and the theoretical model of rolling resistance of high-speed rubber track assembly is established. In accordance with the model above, the key influencing factors and changing trends of rolling resistance are analyzed, which provides a theoretical basis for the performance optimization of high-speed rubber track assembly.

Assembly and Entry of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2): Evaluation Using Virus-Like Particles.

Research on infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) is currently restricted to BSL-3 laboratories. SARS-CoV2 virus-like particles (VLPs) offer a BSL-1, replication-incompetent system that can be used to evaluate virus assembly and virus-cell entry processes in tractable cell culture conditions. Here, we describe a SARS-CoV2 VLP system that utilizes nanoluciferase (Nluc) fragment complementation to track assembly and entry. We utilized the system in two ways. Firstly, we investigated the requirements for VLP assembly. VLPs were produced by concomitant synthesis of three viral membrane proteins, spike (S), envelope (E), and matrix (M), along with the cytoplasmic nucleocapsid (N). We discovered that VLP production and secretion were highly dependent on N proteins. N proteins from related betacoronaviruses variably substituted for the homologous SARS-CoV2 N, and chimeric betacoronavirus N proteins effectively supported VLP production if they contained SARS-CoV2 N carboxy-terminal domains (CTD). This established the CTDs as critical features of virus particle assembly. Secondly, we utilized the system by investigating virus-cell entry. VLPs were produced with Nluc peptide fragments appended to E, M, or N proteins, with each subsequently inoculated into target cells expressing complementary Nluc fragments. Complementation into functional Nluc was used to assess virus-cell entry. We discovered that each of the VLPs were effective at monitoring virus-cell entry, to various extents, in ways that depended on host cell susceptibility factors. Overall, we have developed and utilized a VLP system that has proven useful in identifying SARS-CoV2 assembly and entry features.

Rab27a co-ordinates actin-dependent transport by controlling organelle-associated motors and track assembly proteins

Cell biologists generally consider that microtubules and actin play complementary roles in long- and short-distance transport in animal cells. On the contrary, using melanosomes of melanocytes as a model, we recently discovered that the motor protein myosin-Va works with dynamic actin tracks to drive long-range organelle dispersion in opposition to microtubules. This suggests that in animals, as in yeast and plants, myosin/actin can drive long-range transport. Here, we show that the SPIRE-type actin nucleators (predominantly SPIRE1) are Rab27a effectors that co-operate with formin-1 to generate actin tracks required for myosin-Va-dependent transport in melanocytes. Thus, in addition to melanophilin/myosin-Va, Rab27a can recruit SPIREs to melanosomes, thereby integrating motor and track assembly activity at the organelle membrane. Based on this, we suggest a model in which organelles and force generators (motors and track assemblers) are linked, forming an organelle-based, cell-wide network that allows their collective activity to rapidly disperse the population of organelles long-distance throughout the cytoplasm.

Dynamic Performance of High-Speed Rail Cable Stayed Bridge with Altered Track Assembly

On fast moving world, the interest is being increased for high-speed trains. It provides a sustainable and effective mode of travelling. Till date India was special among the developing nations for not having a high-speed rail corridor. However, by introducing Mumbai–Ahmedabad high-speed rail corridor, it opens up research directed towards efficient design of the supporting structures. In India, construction and upgradation of railways on its top which attracts the researchers for advance research in the same field. Here an attempt is made to understand the railway track formulation and bridging aspect for high speed rail model as per European standards to assess the influence or impact of rail axle load on bridge behavior. Under this scope, a hypothetical case study of “H-Shaped Cable Stayed Bridge” is taken with Rheda 2000 non-ballasted track, vibrating and non-vibrating ballasted track. The analysis is performed by two approaches; first is the track characterized by its finite element model and second is by introducing track through its equivalent weight. The ballast-less track is already a candid approach for rail lines, showing competitiveness against the conventional ballasted track. The reason for the adaptability of the Ballast-less track is its low maintenance and high accessibility of materials. However, on the basis of vibration analysis “Vibrating Ballasted Track” proved decent in terms of performance.

Stabilisation of Stiffer Rail Track Substructure Using Artificial Inclusion

The railway transport system in many countries plays a significant role in the passage of bulk freight and passengers. However, increased train speeds and higher freight loads (large dynamic wheel loads) accelerate the deterioration of rail track substructure. This problem is more critical in isolated rail track locations where the track substructure is much stiffer than the regular surface track assembly such as track at the bridges and tunnels. Ballast is a key track foundation material placed underneath the sleepers which provides structural support against high cyclic and impact stresses caused by moving trains. Inclusion of rubber mats called under ballast mats (UBMs) placed between the ballast and stiffer base layer is one of the measures to minimise the ballast deterioration. In this study, cyclic loads representing fast and heavy haul trains were simulated on stiffer track foundation condition using a large-scale process simulation prismoidal triaxial apparatus to investigate the mitigation of strain, stress and degradation characteristics of ballast stabilised with UBM. These UBMs were locally manufactured from recycled tyre wastes. The results show that ballast on a stiff foundation substructure stabilised with UBM experienced significantly less vertical and lateral deformation, ballast interface and inter-particle stresses and degradation. This study also confirmed that the recycled tyre UBMs used in this study had adequate damping to absorb the energy transmitted to the moving train to the track, thus preventing excessive plastic deformation and degradation of the ballast layer.

Совершенствование системы виброзащиты операторов промышленных тракторов

When developing new models of industrial tractors, compliance with the regulatory requirements for vibration protection of operators is verified at the stage of certification tests. At this stage, development procedures are associated with significant time and material costs. The article proves the possibility to use a computational and experimental technique which allows us to determine the level and frequency content of potentially dangerous vibration sources at the deve­lopment stage; to develop computer models of the system “excitation source – frame – cab – antivibration seat – operator”; to develop proposals to comply with legislative requirements using parametric forecasting. As an example, the problem of vibration in the low frequency range of 2–14 Hz was considered. This vibration is caused by rolling of track rollers on the track chain, which lies on a yielding soil foundation. Basing on the analysis of field test results, the kinematic effect of track rollers on the tractor frame was represented as stationary random narrow-band processes. A mathematical model of the tractor was described by a set of differential equations with random input processes. Methods of statistical dynamics were used to implement the model. The simulation data of T-11 motion with different speeds are given. The results are presented as a set of transfer functions, as well as the spectral densities of changes in generalized model coordinates and accelerations at the driver’s seat. The difference between the calculation results and the experimental data does not exceed 15–20 %. The effect of elastic-viscous characteristics of vibration protection devices on the level of accelerations at the operator’s seat was analyzed. As a result, it was recommended that these characteristics should be changed in order to reduce the vertical vibration acceleration of the driver’s seat. This approach allows us to solve the problems of vibration protection of operators when designing and testing prototype models of road-building machinery. It is achieved by tuning out the system “track assembly – frame – cab – antivibration seat” of resonance phenomena.

Increasing data integrity for improving decision making in production planning and control

Manufacturing companies gather a vast amount of data in order to track production, assembly and logistical processes. Among others, these data are used for updating production schedules, deriving process interventions and calculating key performance indicators. However, the integrity of these production feedback data is regularly impaired by various inconsistencies and errors, which negatively affect the value of these data for any decision-making processes. In this paper, a new approach for increasing the integrity of production feedback data based on an adapted Data Mining algorithm is proposed to compensate for a typical data error in production feedback data.

Numerical analysis of new pre-installed steel modular railroad track assembly

Due to the modularity of the traditional track and the discreteness of the ballast bed, the application of the repeated and random train load would inevitably result in the accumulation of residual deformation and the track damage. A new steel pre-installed modular railroad track assembly was designed to provide better stability and reduce deformation. It includes a plurality of spaced-apart cross-ties, two side ties, intermediate ties and a pair of rails road track rails. In order to figure out the mechanical performance of this new steel pre-installed modular railroad track assembly, the 3-D finite element model of the steel modular railroad track including with the track, ballast bed, sub-ballast and the sub-grade was built. In this model, the load distribution and the vertical deformation of ties with different cross sections were discussed, and the stresses of the steel modular railroad track and the ballast bed were analyzed. The results indicate that, compared with the traditional track, the single wheel load will transfer to more ties of the new steel modular railroad track and the integrality of the new steel modular railroad track is much better. The maximum deflection of the steel modular railroad track located at the point of load application (under the wheel load). It is much smaller than that of the traditional track. As a result, it can be concluded that the new steel modular railroad track is more likely to induce less deflection under the series wheel load and have better rail regularity.

Biosilver nanoparticle interface offers improved cell viability.

Silver nanoparticles (AgNP) are promising candidates for fighting drug-resistant infections because of their intrinsic antimicrobial effect. The design of high-yield antimicrobial molecules may inadvertently cause variation in host cells' biological responses. While many factors affect AgNPs' efficacy, their surface is exposed to the biological environment and thus plays a critical role in both the preservation of antimicrobial efficacy against pathogens and the modulation of host cells cytotoxicity. This work investigated an engineered biomimetic interface approach to controlling AgNP surface properties to provide them a competitive advantage in a biological environment. Here, a fusion protein featuring a silver-binding peptide (AgBP) domain was engineered to enable self-assembly and track assembly by a green fluorescent protein (GFP) reporter. Following AgNP functionalisation with GFP-AgBP, their antimicrobial and cytotoxic properties were evaluated. GFP-AgBP binding affinity to AgNPs was evaluated using localized surface plasmon resonance sensing. The GFP-AgBP biomimetic interface on AgNPs' surfaces provided sustained antibacterial efficacy at low concentrations based on bacterial growth inhibition assays. Viability and cytotoxicity measurements in fibroblast cells exposed to GFP-AgBP protein-functionalised AgNPs showed significant improvement compared to controls. Biointerface engineering offers promise towards tailoring AgNP antimicrobial efficacy while addressing safety concerns to maintain optimum cellular interactions.

Simulation of the formation of vibration loading of operator workplace of industrial tractor

The check of compliance with legislative requirements for vibration protection of operators is carried out at the stage of certification testing of new and upgrading products. At this stage, the further development is associated with high time and material costs. The article substantiates the possibility of use of a calculation and experimental method which allows to determine at the development stage the level and frequency content of potentially dangerous sources of vibration; to develop a computer model for the system «excitation source - frame - cab - antivibration seat - operator»; to make out proposals to comply with legislative requirements by means of parametric forecasting. As an example, the problem of vibration in the low frequency range of 2-14 Hz is considered. This vibration is the result of the process of rolling of track rollers on track chain that lies on the yieldable soil foundation. According to biomedical research, the resonance frequencies of critical parts of human body are in this low frequency range, which is displayed in sanitary norms. Based on the analysis of field test results, the kinematic impact of track rollers on tractor frame is represented as stationary narrow-band random processes. Mathematical model of the system is described by a set of differential equations with random input processes. The methods of statistical dynamics are used to implement the model. The simulation results are presented as a set of transfer functions. They represent the distribution of resonance frequencies of angular and heave oscillations of the separate system elements and the spectral density functions. These results allow to obtain the quantitative estimations in the form of mean-square values of the output processes. The use of this approach allows to solve the problems of vibration protection of operator at the stages of design and testing of prototypes of road-building machinery. It is achieved by tuning-out of the system «track assembly - frame - cab - antivibration seat» from resonance phenomena and by introducing some design solutions.

Flexible field goniometer system: the Goniometer for Outdoor Portable Hyperspectral Earth Reflectance

This paper describes a portable hyperspectral goniometer system for measurement of hemispherical conical reflectance factor (HCRF) data for terrestrial applications, especially in the coastal zone. This system, the Goniometer for Portable Hyperspectral Earth Reflectance (GOPHER), consists of a computer-controlled Spectra Vista Corporation HR-1024 full-range spectrometer mounted on a rotating arc and track assembly, allowing complete coverage in zenith and azimuth of a full hemisphere for recording HCRF. The control software allows customized scan patterns to be quickly modified in the field, providing for flexibility in recording HCRF and the opposition effect with varying grid sizes and scan ranges in both azimuth and zenith directions. The spectrometer track can be raised and lowered on a mast to accommodate variations in terrain and land cover. To minimize the effect of variations in illumination during GOPHER scan cycles, a dual-spectrometer approach has been adapted to link records of irradiance recorded by a second spectrometer during the GOPHER HCRF scan cycle. Examples of field data illustrate the utility of the instrument for coastal studies.

Multibody Dynamic Stress Simulation of Rigid-Flexible Shovel Crawler Shoes

Electric shovels are used in surface mining operations to achieve economic production capacities. The capital investments and operating costs associated with the shovels deployed in the Athabasca oil sands formation are high due to the abrasive conditions. The shovel crawler shoes interact with sharp and abrasive sand particles, and, thus, are subjected to high transient dynamic stresses. These high stresses cause wear and tear leading to crack initiation, propagation and premature fatigue failure. The objective of this paper is to develop a model to characterize the crawler stresses and deformation for the P&H 4100C BOSS during propel and loading using rigid-flexible multi-body dynamic theory. A 3-D virtual prototype model of the rigid-flexible crawler track assembly and its interactions with oil sand formation is simulated to capture the model dynamics within multibody dynamics software MSC ADAMS. The modal and stress shapes and modal loads due to machine weight for each flexible crawler shoes are generated from finite element analysis (FEA). The modal coordinates from the simulation are combined with mode and stress shapes using modal superposition method to calculate real-time stresses and deformation of flexible crawler shoes. The results show a maximum von Mises stress value of 170 MPa occurring in the driving crawler shoe during the propel motion. This study provides a foundation for the subsequent fatigue life analysis of crawler shoes for extending crawler service life.

Features of combined friction in contact patch during cornering of track-type tractor on deforming ground

The article discusses the question of refinement of analytical dependencies determining the summarized external forces of resistance in the system of differential equations of motion. For describing the interaction of track assembly with the ground in curvilinear motion the model of combined friction is used.

Rigid multi-body kinematics of shovel crawler-formation interactions

Large capacity shovels are deployed in surface mining operations for achieving economic bulk production targets. These shovels use crawler tracks for effective terrain engagement in these environments. Shovel reliability, maintainability, availability and efficiency depend on the service life of the crawler tracks. In rugged and challenging terrains, crawler wear, tear, cracks and failure are extensive resulting in prolonged downtimes with severe economic implications. In particular, crawler shoe wear, tear, cracks and fatigue failures can be expensive in terms of maintenance costs and production losses. No fundamental research has been undertaken to understand the crawler-formation interactions in challenging and rugged terrains in surface mining operations. This study forms the foundations for providing long-term solutions to crawler failure problems. The kinematic equations governing the crawler-formation interactions have been formulated to characterise the crawler motions during shovel production. These equations capture the motions governing the link pin joint, oil sand terrain joint and driving constraints based on the multi-body rigid theory. Crawler propel is achieved by using prescribed velocities along a translational degree of freedom (DOF) and a translational and rotational DOF. The crawler kinematic solutions show that the 3-D crawler–terrain model results in 132 DOFs and requires dynamic modelling to obtain the unknown degrees of freedom. A 3-D virtual prototype model is built to capture the crawler-formation interaction in MSC ADAMS based on the rigid body crawler kinematics. The virtual prototype simulator is supplied with mass properties of crawler shoe, mass, stiffness and damping characteristics of oil sand and external loads due to machine weight and contact forces to obtain the time variation of position, velocity and acceleration for the crawler–terrain engagement for given driving constraints. The results from the driving constraints yield a non-linear longitudinal motion of the crawler track assembly. The crawler track lateral and vertical displacements during translation-only motion fluctuates with maximum magnitudes of 0.7 and 3.6 cm. Similarly the fluctuating longitudinal, lateral and vertical velocities and accelerations have maximum magnitudes of 0.22, 0.046 and 0.56 m/s and 7.41, 1.73, and 34.9 m/s2, respectively. This research provides a strong foundation for further study on developing flexible crawler track model for predicting crawler shoes dynamic stress distributions, cracks development and propagation and fatigue analysis during shovel operations.

The UCSC Genome Browser database: 2015 update.

Launched in 2001 to showcase the draft human genome assembly, the UCSC Genome Browser database (http://genome.ucsc.edu) and associated tools continue to grow, providing a comprehensive resource of genome assemblies and annotations to scientists and students worldwide. Highlights of the past year include the release of a browser for the first new human genome reference assembly in 4 years in December 2013 (GRCh38, UCSC hg38), a watershed comparative genomics annotation (100-species multiple alignment and conservation) and a novel distribution mechanism for the browser (GBiB: Genome Browser in a Box). We created browsers for new species (Chinese hamster, elephant shark, minke whale), ‘mined the web’ for DNA sequences and expanded the browser display with stacked color graphs and region highlighting. As our user community increasingly adopts the UCSC track hub and assembly hub representations for sharing large-scale genomic annotation data sets and genome sequencing projects, our menu of public data hubs has tripled.

Analysis and Optimization of Cushion Seat Supporting Members

Seat structures play a major role in the car passive safety. Due to their adjustment function mechanisms are generally involved in the seat failure mode. With the current evolution of automotive techniques, one of major automotive industry priorities is to decrease the product mass, design quicker and more efficient vehicles, emphasizing on travelling greater distances in short interval of time. For this comfort with safety of passengers is very important, thus the design of the seating system is very important. At the same time, seat rails have to fulfill high quality criteria, there are very strict requirements regarding strength and crash worthiness as the seat rail is regarded as a safety component it transfers forces from the driver / passenger to the car floor structure in case of a crash and they have to provide individual length adjustments possible. Amongst many parts, the seat tracks (upper and lower tracks) carry most of the load on seat structure considering human load. The aim of this project is to optimize an automotive seat track by reducing track thickness and its cost subjecting to static analysis. The adopted design has thickness of seat track as 1.5mm; scope of the present work involves Finite Element Modeling of Seat track assembly using HYPERMESH R 10. Pre-processing steps such as updating of element type, material properties, application of loads and Boundary condition is performed using HYPERMESH. The element type considered for the analysis is SHELL. Processing is carried using ANSYS. The results in the form of stress and displacement are extracted using HYPER VIEW.