Unified Assembly Research Articles

The Reduced-Order Modeling Approach for a Double-Damper Concept: A Comparison with a Single Damper for Comfort Analysis

This paper explores the modeling and simulation of an innovative double-damper suspension system, evaluating its effectiveness through different test scenarios. The double damper integrates two individual dampers into a unified assembly. The modeling process involves representing the damper as two distinct dampers and a body block, accounting for the additional degree of freedom introduced by combining the two dampers. Simulink/MATLAB is employed for modeling the pressure, discharge, and force equations of the damper. A simplified quarter-car model is designed to conduct simulations for different road profiles, evaluating the efficacy of this double-damper model. The reduced-order modeling approach, suitable for complex systems like dampers, is utilized. Dedicated mathematical models are utilized to examine both single- and double-damper configurations, with the resulting non-linear equations solved using Newton’s iterative method. The equations derived for the single damper provide the basis for modeling the double-damper system. In this model, two separate dampers, each possessing similar properties, are simulated and considered to be rigidly linked at their connection point. Consequently, it is assumed that a portion of the force and velocity experienced by the lower damper is transmitted to the upper damper, and vice versa. Simulation results demonstrate that the innovative double-damper design outperforms a single passive damper in attenuating the oscillations of both the sprung and unsprung masses. Moreover, this innovative concept offers increased adaptability to balance between ride comfort and road holding, a feature previously limited to passive suspension systems.

A highly sensitive diaphragm pressure sensor based on fiber Bragg grating with multiprobe configuration

The demand for accurate low-pressure sensing has become indispensable across diverse industries and research domains, where meticulous pressure monitoring holds paramount significance. This research work presents the development of a multiprobe extrinsically sensitive low pressure fiber Bragg grating (FBG) sensor. Three distinct diaphragm-based FBG sensing probes, equipped with silicone diaphragms of 0.5 mm, 1 mm, and 2 mm thickness, are developed within a unified assembly. This design offers the flexibility to select a probe based on the pressure magnitude and desired sensitivity and resolution. The displacement of diaphragm centers within the probes, caused by pressure variations in gas pipe channels, is actuated through an FBG-cantilever system. The sensor exhibits a dynamic range spanning 0 to 10 psi, featuring a peak sensitivity of 1.635 nm/psi. With a negligible hysteresis of 0.2 % observed in a complete operational cycle, the sensor demonstrates consistent stability across various constant pressure conditions, characterized by an average transient of <1 %. Furthermore, cyclic testing reveals an average deviation of 1.58 % in sensor response. This innovative sensor offers promising avenues for industrial applications and research and development endeavors that necessitate precise and reliable pressure measurements in the low pressure domains.

Human-Robot Shared Assembly Taxonomy: A step toward seamless human-robot knowledge transfer

Future manufacturing will witness a shift in human-robot relationships toward collaboration, compassion, and coevolution. This will require seamless human-robot knowledge transfer. Differences in language and knowledge representation hinder the transfer of knowledge between humans and robots. Thus, a unified knowledge representation system that can be shared by humans and robots is essential. Driven by this need in a product assembly scenario, we propose the Human-Robot Shared Assembly Taxonomy (HR-SAT). With HR-SAT, any comprehensive assembly task can be represented as a knowledge graph that both humans and robots can understand. To ensure consistency in task decomposition and representation, we define the key elements of HR-SAT. HR-SAT incorporates rich assembly information and provides necessary information for diverse applications, e.g., process planning, quality checking, and human-robot collaboration. The usage and practicality of HR-SAT are demonstrated through two case studies. As a unified assembly process representation schema, HR-SAT constitutes a critical step toward seamless human-robot knowledge transfer. The specifications of HR-SAT and the two case studies are available at: https://iai-hrc.github.io/hr-sat.

Connection of Bipolar Plate with Graphite Felt Electrode for Vanadium Flow Battery Using a Powder Thermal Unification Method

Carbon felt electrodes are usually compressed against the bipolar plates in order to decrease the contact resistance, but it leads to high pressure drop and consumption of pumping energy in conventional vanadium redox flow battery stacks. This paper describes the fabrication of an effective way to unify the bipolar plate and graphite felt electrode in order to improve the battery efficiency at lower felt compression pressure. The unification process involves a thermal fusion technique with a component design consisting of bipolar plate, graphite felt electrode and connecting powder. The powder comprises either polyvinylidene difluoride or a mixture of polyvinylidene difluoride and conductive carbon black. The interfacial bonding substance determines the electrical resistance of the resultant fabricated unified assembly. The electrical resistance results prove that the carbon black proportion in the bonding element substantially reduces the electrical resistance. The optimum quantity of carbon black in the powder is found to be 40 wt%. Micro-computed tomography analysis findings indicate that thermally unified assembly interfacial contact electrode porosity is slightly lower than that of an unbonded sample. A two-cell vanadium redox flow battery stack with integrated unified assembly achieves a rather constant energy efficiency of 76% during 100 cycles with 5% electrode compression at a current density of 80 mA cm−2.

A node2vec-based graph embedding approach for unified assembly process information modeling and workstep execution time prediction

The trend of customized production results in the demand for higher level of automation, in which artificial intelligence decision-making dominates. As the core of smart manufacturing systems, intelligent services stand a significant role in the analysis, prediction, and adjustment of production process, which is inseparable from the effective semantic modeling of the procedures and elements involved. However, there is an absence of unified modeling of assembly process, including both geometric and non-geometric information, leading to the incomprehensiveness when providing data support for intelligent services. To fill this gap, a generic node2vec-based parameterized representation of geometric elements and assembly constraints approach is proposed. Firstly, the information structure of assembly process is established, in which the geometric elements and topological relationships of the product are abstracted into a network. Secondly, node2vec is adopted for the graph embedding to generate preset dimension vectors corresponding to the nodes in the geometric network. As the edges in the network, the vectors corresponding to the assembly constraints, which are regarded as the parameterized representations, can be obtained through node vector calculation. Moreover, an assembly workstep execution time prediction method based on historical data is introduced with the parameterized representations of assembly constraints as the carriers of geometric topological information. At last, an industrial case study is illustrated to show the entire process of constraint parameterized representations and workstep execution time prediction, indicating the feasibility and availability of the method proposed.

A Setup for Complex Investigation of Mechanical Characteristics of Structural Materials for NPP Equipment

The complex experimental equipment has been developed and manufactured in compliance with the existing standards for measuring hardness and strength characteristics via the method of instrumented indentation, as well as for short-term static uniaxial tensile tests of structural materials and small punch testing of miniature disk specimens in the macrorange of loads of 2–10,000 N. This allows one to obtain the necessary characteristics of hardness and strength in relation to the current state of materials of the main equipment at NPP and thereby minimize the volume of material used for the production of specimens on the same setup employing various normative techniques of both destructive and non-destructive inspections. The equipment is designed in the form of replaceable units: indentation, tension, and punching of miniature disk specimens, which are installed depending on the test method. As a result, there is a unified assembly that makes it possible to reduce the effect of instrument errors in the validity of the data obtained using different test methods and facilitate its modification according to the other tests. The developed experimental equipment has been tested using the segment of metal of the double ball pipe wall ∅990 × 70 mm (the basic metal is 10GN2MFA steel and the deposited material is 08Kh19N10G2B steel) of the Du850 main circulation pipeline of NPP from WWER-1000 reactor pressure vessel. The mechanical characteristics obtained by the methods of indirect control were compared with those obtained from standard tensile tests. At the same time, the deviation of the values of yield strength and ultimate strength obtained employing the indirect control methods from the values obtained in the standard tensile testing is within the limits recommended by the normative documents.

The total synthesis and functional evaluation of fourteen stereoisomers of yaku'amide B. The importance of stereochemistry for hydrophobicity and cytotoxicity.

Yaku'amide B is a highly unsaturated linear tridecapeptide and an extremely potent cytotoxin. Herein, we describe the synthesis of fourteen new stereoisomers of yaku'amide B using a unified assembly strategy. The hydrophobicities and cytotoxicities of these analogues were analyzed, along with those of four previously prepared isomers. Although all of the analogues share a common planar structure, their log D values varied significantly (3.39-5.32), presumably reflecting their distinct three-dimensional shapes. Subnanomolar-level cytotoxicity was observed for the natural yaku'amide B and its epimer of the N-terminal acyl group, whereas the other sixteen isomers exhibited 13- to 1200-fold weaker activities than that of the natural isomer. These data indicated the importance of the overall stereostructure of the 13-mer sequence of yaku'amide B for exerting its potent toxicity.

Unified assembly- and disassembly-line model formulae

Purpose – There is a rich body of literature on sequencing assembly and on sequencing disassembly, but little that either fuses or contrasts the two, which may be valuable for long-range planning in the closed-loop supply chain and simply convenient in terms of consistency in nomenclature and mathematical formulations. The purpose of this paper is to concisely unify and summarize assembly and disassembly formulae – as well as to add new formulations for completeness – and then demonstrate the similarities and differences between assembly and disassembly. Design/methodology/approach – Along with several familiar assembly-line formulae which are adapted here for disassembly, five (two specific and three general) metrics and a comparative performance formula from disassembly-line balancing are proposed for use in assembly- and disassembly-line sequencing and balancing either directly, through generalization, or with some extension. The size of assembly and disassembly search spaces are also quantified and formulated. Three new metrics are then developed from each of the general metrics to demonstrate the process of using these general formulae as prototypes. Findings – The three new metrics along with several of the original metrics are selectively applied to a simple, notional case study product to be sequenced on an assembly line and then on a disassembly line. Using these analytical results, the inherent differences between assembly and disassembly, even for a seemingly trivial product, are illustrated. Originality/value – The research adds several new assembly/disassembly metrics, a case study, unifies the evaluation formulae that assembly and disassembly hold in common as well as structuring prototype formulae for flexibility in generating new evaluation criteria for both, and quantifies (using the case study) how assembly and disassembly – while certainly possessing similarities – also demonstrate measurable differences that can be expected to affect product design, planning, production, and end-of-life processing.

Unified Polymerization Mechanism for the Assembly of ASC-Dependent Inflammasomes

Inflammasomes elicit host defense inside cells by activating caspase-1 for cytokine maturation and cell death. AIM2 and NLRP3 are representative sensor proteins in two major families of inflammasomes. The adaptor protein ASC bridges the sensor proteins and caspase-1 to form ternary inflammasome complexes, achieved through pyrin domain (PYD) interactions between sensors and ASC and through caspase activation and recruitment domain (CARD) interactions between ASC and caspase-1. We found that PYD and CARD both form filaments. Activated AIM2 and NLRP3 nucleate PYD filaments of ASC, which, in turn, cluster the CARD of ASC. ASC thus nucleates CARD filaments of caspase-1, leading to proximity-induced activation. Endogenous NLRP3 inflammasome is also filamentous. The cryoelectron microscopy structure of ASC(PYD) filament at near-atomic resolution provides a template for homo- and hetero-PYD/PYD associations, as confirmed by structure-guided mutagenesis. We propose that ASC-dependent inflammasomes in both families share a unified assembly mechanism that involves two successive steps of nucleation-induced polymerization. PAPERFLICK:

Structure and structural transition of chiral domains in oligo(p-phenylenevinylene) assembly investigated by scanning tunneling microscopy

OPV3-CHO molecules are employed to prepare assembly on highly oriented pyrolytic graphite, and the so-prepared assembly is investigated by scanning tunneling microscopy. In the assembly chiral domains are observed with various structures such as linear and windmill. The chiral structural formation, stability, transition, and possible unification are intensively studied. After thermal annealing, linear structure was the only structure. To achieve a unified assembly with a single structure, an efficient method is proposed by coadsorption of OPV3-CHO with selected molecules. For example, an assembly with side-by-side helix structure is formed by a simple coadsorption of OPV3-CHO with alkyl bromide (C(n)H(2n+1)Br, n = 15-18). The experiments by cocrystallization of OPV3-CHO/C(n)H(2n+1)X (X = Cl, Br, and I) show the important role of halogen bonding in formation of the uniform structure. The results are significant in understanding the intermolecular noncovalent interactions that dominate the surface structure and chirality.

Parametric Unification of Automotive Design Factors on Development and Production

The paper sets the method for design and production of automobiles of functional modules based on the transfer to unified assembly units. The method of functional modules detailed parameters unification considered. The article shows the problems which may arise while using functional modules. The methods for solution of these problems are offered.

Type IV Pilus Structure by Cryo-Electron Microscopy and Crystallography: Implications for Pilus Assembly and Functions

Type IV pili (T4P) are long, thin, flexible filaments on bacteria that undergo assembly-disassembly from inner membrane pilin subunits and exhibit astonishing multifunctionality. Neisseria gonorrhoeae (gonococcal or GC) T4P are prototypic virulence factors and immune targets for increasingly antibiotic-resistant human pathogens, yet detailed structures are unavailable for any T4P. Here, we determined a detailed experimental GC-T4P structure by quantitative fitting of a 2.3 A full-length pilin crystal structure into a 12.5 A resolution native GC-T4P reconstruction solved by cryo-electron microscopy (cryo-EM) and iterative helical real space reconstruction. Spiraling three-helix bundles form the filament core, anchor the globular heads, and provide strength and flexibility. Protruding hypervariable loops and posttranslational modifications in the globular head shield conserved functional residues in pronounced grooves, creating a surprisingly corrugated pilus surface. These results clarify T4P multifunctionality and assembly-disassembly while suggesting unified assembly mechanisms for T4P, archaeal flagella, and type II secretion system filaments.

A unified assembly mode revealed by the structures of tetrameric L27 domain complexes formed by mLin-2/mLin-7 and Patj/Pals1 scaffold proteins

Initially identified in Caenorhabditis elegans Lin-2 and Lin-7, L27 domain is a protein-protein interaction domain capable of organizing scaffold proteins into supramolecular assemblies by formation of heteromeric L27 domain complexes. L27 domain-mediated protein assemblies have been shown to play essential roles in cellular processes including asymmetric cell division, establishment and maintenance of cell polarity, and clustering of receptors and ion channels. The structural basis of L27 domain heteromeric complex assembly is controversial. We determined the high-resolution solution structure of the prototype L27 domain complex formed by mLin-2 and mLin-7 as well as the solution structure of the L27 domain complex formed by Patj and Pals1. The structures suggest that a tetrameric structure composed of two units of heterodimer is a general assembly mode for cognate pairs of L27 domains. Structural analysis of the L27 domain complex structures further showed that the central four-helix bundles mediating tetramer assembly are highly distinct between different pairs of L27 domain complexes. Biochemical studies revealed that the C-terminal alpha-helix responsible for the formation of the central helix bundle is a critical specificity determinant for each L27 domain in choosing its binding partner. Our results provide a unified picture for L27 domain-mediated protein-protein interactions.

Integrated knowledge-based Petri net intelligent flexible assembly planning

Automatic assembly planning is recognized as an important tool for reducing manufacturing costs in concurrent product and process development. A novel knowledge-based Petri net (KBPN) is defined, based on the incorporation of expert systems into the usual Petri nets, and used for a unified assembly knowledge representation scheme. A KBPN-approach integrated with a sequence generation algorithm is proposed for the modeling, planning, simulation, analysis and evaluation of the flexible assembly system (FAS). The developed KBPN-based assembly planning system (KAPS) can automatically adjust the deviations between the theoretical planning parameters and the process parameters of real assembly operations to guarantee the best strategies and plans (sequences) for flexible assembly. The research findings are exemplified with a simple assembly to show the effectiveness of the method.

Gas-Lubricated Foil Bearings for High Speed Turboalternator—Construction and Performance

Foil bearings were designed and fabricated to replace pivoted-shoe journal bearings in a Brayton cycle turboalternator, within space limitations and constraints imposed by the existing machine. The foil bearings were integrated into a unified assembly with the rotor, housing, seals, and gimbal-mounted thrust bearing, without changes and modifications of machine components other than the journal bearings. The gas-lubricated foil bearings, which require no external pressure-source, furnished a stable support for a 21.9 pound rotor in the vertical attitude at speeds to 43,200 rpm. Excellent wipe-wear characteristics permitted well over 1000 start-stop cycles, without deterioration of performance in the entire speed range. The paper reviews salient aspects of design, fabrication, and performance. An account is given of rotor dynamics during starting, stopping, and traversing the region of resonances. The state of journal and foil surfaces is examined following intensive start-stop cycling and high-speed runs over extended periods of time.

Towards Unified and Convergent Theory of Elementary Particles

In order to get rid of the well-known divergence difficulty in the quantum field theory, fictitious particles with an indefinite metric are introduced. The difficulty concerning the probabilistic interpretation caused by the indefinite metric is satisfactorily avoided by making use of the of fictitious particles, characterized by the complex poles. Based on such a general possibility, we investigate the Nagoya model assuming B-matter to be a unified assembly of fictitious particles. The divergence difficulty in the quantum field theory has been a long-pending object for the theoretical physicists from its beginning and many efforts to overcome this difficulty have been made without any satisfactory solution. Among these attempts, however, the introduction of the indefinite metric in the Hilbert space seems to have a special theoretical ground/) when taking into consideration the recent investigation of the axiomatic formulation of the quantum field theory.2) As noticed by many authors, this attempt seems still to have a serious difficulty that it can not reconcile with the probabilistic interpretation in the quantum theory or with the requirement of the macroscopic causality.3),4) However, it should be noticed that the latter conclusion is based on a purely perturbational consideration. Let us consider the well-known Pauli-Villars type regularization. Fictitious particles introduced to regularize the divergence have in general a large mass and interact with physical particles. Thus, at high energies over the threshold of the production of these fictitious particles, they must come out with an indefinite metric and thus violate the probabilistic interpretation. 4 ),O) Is this consideration, however, really correct? There necessarily arises the question of the stability of these particles. Such a fictitious particle which has a large mass and interacts with physical particles in general must not be stable. However, it should be noticed that the instability of fictitious particles with indefinite metric is only superficial and has an essentially different aspect from the instability of the usual unstable particles with a definite metric. That 1S,