Experimental Study on the Reduction Effect of Pit Texture on Disassembly Damage for Interference Fit

After remanufacturing disassembly,several kinds of friction damages can be found on the mating surface of interference fit.These damages should be repaired and the cost is closely related to the severity of damages.Inspired by the excellent performance of surface texture in wear reduction,5 shapes of pit array textures are added to the specimens’surface to study their reduction effect of disassembly damage for interference fit.The results of disassembly experiments show that the order of influence of texture parameters on disassembly damage is as follows:equivalent circle diameter of single texture,texture shape and texture surface density.The influence of equivalent circle diameter of single texture and texture shape are obviously more significant than that of texture surface density.The circular texture with a surface density of 30%and a diameter of 100μm shows an excellent disassembly damage reduction effect because of its perfect ability of abrasive particle collection.And the probability of disassembly damage formation and evolution is also relatively small on this kind of textured surface.Besides,the load-carrying capacity of interference fit with the excellent texture is confirmed by load-carrying capacity experiments.The results show that the load-carrying capacity of the excellent texture surface is increased about 40%compared with that of without texture.This research provides a potential approach to reduce disassembly damage for interference fit.

Using genetic/simulated annealing algorithm to solve disassembly sequence planning

Disassembly sequence planning （DSP） plays a significant role in maintenance planning of the aircraft. It is used during the design stage for the analysis of maintainability of the aircraft. To solve product disassembly sequence planning problems efficiently, a product disassembly hybrid graph model, which describes the connection, non-connection and precedence relationships between the product parts, is established based on the characteristic of disassembly. Farther, the optimization model is provided to optimize disassembly sequence. And the solution methodology based on the genetic/simulated annealing algorithm with binaxy-tree algorithm is given. Finally, an example is analyzed in detail, and the result shows that the model is correct and efficient.

Automated Disassembly Sequence Prediction for Industry 4.0 Using Enhanced Genetic Algorithm

The evolution of Industry 4.0 made it essential to adopt the Internet of Things(IoT)and Cloud Computing(CC)technologies to perform activities in the new age of manufacturing.These technologies enable collecting,storing,and retrieving essential information from the manufacturing stage.Data collected at sites are shared with others where execution automatedly occurs.The obtained information must be validated at manufacturing to avoid undesirable data losses during the de-manufacturing process.However,information sharing from the assembly level at the manufacturing stage to disassembly at the product end-of-life state is a major concern.The current research validates the information optimally to offer a minimum set of activities to complete the disassembly process.An optimal disassembly sequence plan(DSP)can possess valid information to organize the necessary actions in manufacturing.However,finding an optimal DSP is complex because of its combinatorial nature.The genetic algorithm(GA)is a widely preferred artificial intelligence(AI)algorithm to obtain a near-optimal solution for the DSP problem.The converging nature at local optima is a limitation in the traditional GA.This study improvised the GA workability by integrating with the proposed priori crossover operator.An optimality function is defined to reduce disassembly effort by considering directional changes as parameters.The enhanced GA method is tested on a real-time product to evaluate the performance.The obtained results reveal that diversity control depends on the operators employed in the disassembly attributes.The proposed method’s solution can be stored in the cloud and shared through IoT devices for effective resource allocation and disassembly for maximum recovery of the product.The effectiveness of the proposed enhanced GA method is determined by making a comparative assessment with traditional GA and other AI methods at different population sizes.

Disassemblability Modeling Technology of Configurable Product Based on Disassembly Constraint Relation Weighted Design Structure Matrix(DSM)

The current research of configurable product disassemblability focuses on disassemblability evaluation and disassembly sequence planning. Little work has been done on quantitative analysis of configurable product disassemblability. The disassemblability modeling technology for configurable product based on disassembly constraint relation weighted design structure matrix （DSM） is proposed. Major factors affecting the disassemblability of configurable product are analyzed, and the disassembling degrees between components in configurable product are obtained by calculating disassembly entropies such as joint type, joint quantity, disassembly path, disassembly accessibility and material compatibility. The disassembly constraint relation weighted DSM of configurable product is constructed and configuration modules are formed by matrix decomposition and tearing operations. The disassembly constraint relation in configuration modules is strong coupling, and the disassembly constraint relation between modules is weak coupling, and the disassemblability configuration model is constructed based on configuration module. Finally, taking a hydraulic forging press as an example, the decomposed weak coupling components are used as configuration modules alone, components with a strong coupling are aggregated into configuration modules, and the disassembly sequence of components inside configuration modules is optimized by tearing operation. A disassemblability configuration model of the hydraulic forging press is constructed. By researching the disassemblability modeling technology of product configuration design based on disassembly constraint relation weighted DSM, the disassembly property in maintenance, recycling and reuse of configurable product are optimized.

Disassembly Sequence Planning:A Survey

It is well-recognized that obsolete or discarded products can cause serious environmental pollution if they are poorly be handled.They contain reusable resource that can be recycled and used to generate desired economic benefits.Therefore,performing their efficient disassembly is highly important in green manufacturing and sustainable economic development.Their typical examples are electronic appliances and electromechanical/mechanical products.This paper presents a survey on the state of the art of disassembly sequence planning.It can help new researchers or decision makers to search for the right solution for optimal disassembly planning.It reviews the disassembly theory and methods that are applied for the processing,repair,and maintenance of obsolete/discarded products.This paper discusses the recent progress of disassembly sequencing planning in four major aspects:product disassembly modeling methods,mathematical programming methods,artificial intelligence methods,and uncertainty handling.This survey should stimulate readers to be engaged in the research,development and applications of disassembly and remanufacturing methodologies in the Industry 4.0 era.

STUDY ON HUMAN-COMPUTER SYSTEM FOR STABLE VIRTUAL DISASSEMBLY

The cooperative work between human being and computer based on virtual reality (VR) is investigated to plan the disassembly sequences more efficiently. A three-layer model of human-computer cooperative virtual disassembly is built, and the corresponding human-computer system for stable virtual disassembly is developed. In this system, an immersive and interactive virtual disassembly environment has been created to provide planners with a more visual working scene. For cooperative disassembly, an intelligent module of stability analysis of disassembly operations is embedded into the human-computer system to assist planners to implement disassembly tasks better. The supporting matrix for stability analysis of disassembly operations is defined and the method of stability analysis is detailed. Based on the approach, the stability of any disassembly operation can be analyzed to instruct the manual virtual disassembly. At last, a disassembly case in the virtual environment is given to prove the validity of above ideas.

End-of-life vehicle recycling based on disassembly

The end-of-life vehicle recycling was studied based on the disassembly. The end-of-life recycling and the disassembly were reviewed and discussed. A disassembly experiment of an end-of-life engine was carried out, which strictly recorded the process of dismantling. Based on the results, a model of the end-of-life recycling was presented. In this model, the end-of-life parts were classified by three ways which included to recycle directly, to recycle after remanufacturing and to discard. By using this model, the dismantling efficiency and the recycling rate can be improved. Also, it obtains a good result after used in a dismantling factory.

Neighborhood Modularization‑based Artificial Bee Colony Algorithm for Disassembly Planning with Operation Attributes

The recycling and remanufacturing of end-of-life products are significant for environmental protection and resource conservation.Disassembly is an essential process of remanufacturing end-of-life products.Effective disassembly plans help improve disassembly efficiency and reduce disassembly costs.This paper studies a disassembly planning problem with operation attributes,in which an integrated decision of the disassembly sequence,disassembly directions,and disassembly tools are made.Besides,a mathematical model is formulated with the objective of minimizing the penalty cost caused by the changing of operation attributes.Then,a neighborhood modularization-based artificial bee colony algorithm is developed,which contains a modular optimized design.Finally,two case studies with different scales and complexities are used to verify the performance of the proposed approach,and experimental results show that the proposed algorithm outperforms the two existing methods within an acceptable computational time.

Crystal Structure of Sar1[H79G]-GDP Which Provides Insight into the Coat-controlled GTP Hydrolysis in the Disassembly of COP Ⅱ

Sarl is a small GTPase involved in COPⅡ vesicle transport. Previous studies showed that H79G mutation of Sarl can lock Sarl in its GTP-bound active conformation, stabilize coat assembly, and prevent the disassembly of COP Ⅱ vesicle coats by reducing Sec23/24 GAP- stimulated hydrolysis. We show here that the replacement of His79 by glycine induces a large conformation change in switch Ⅱ and results in the lost of hydrogen bond between His79 and its associated nucleophilic water molecule that was hypothesized to reduce the GAP-stimulated hydrolysis during the COP Ⅱ assembly and disassembly. These results confirm that the switch Ⅱ conformation is important for COP Ⅱ disassembly through coat-controlled GTP hydrolysis.

p38 MAP kinase is necessary for melanoma-mediated regulation of VE-cadherin disassembly

Introduction Vascular endothelial (VE)-cadherin is localized to the endothelial borders and the adherens junctions,which are regulated by changes in mitogen activated protein kinases (MAPK),GTPases,and intracellular calcium. We previously

Analysis of Mobile Phone Reliability Based on Active Disassembly Using Smart Materials

When using shape memory materials into active disassembly of actual electronic products, because the elastic modulus of shape memory materials is affected by the temperature is relatively large, therefore, the main difference of environmental reliability between active disassembly products and common products is the impact of collision and vibration under different temperature. Establishing three-dimensional analysis model, comparing the impact of collision and vibration of mobile phone shells which are made up of PVC materials after casting & radiation and PC/ABS materials under different temperature. Analyzing the reliability of mobile phone under different temperature and optimizing its structure according to data of testing.

Disassembly Evaluation in Design of a System Using a Multi-Parameters Index

In order to help designers, consider disassembly in their design activities, a method for evaluation of product disassembly is proposed. Criteria characterizing the disassembility of a product are identified. Each criterion is assigned a coefficient, thus proposing an index of easy fixations (Iff) as a design indicator to evaluate the level of disassembly of a solution generated by the designer. This index is calculated as a weighted average of the indicators for evaluating the disassembility of the product. The proposed method uses information such as the list of subsets or parts, the component tree, the part geometry, the functional links between components and parts, the properties of the components. It has been tested on one product: the soy roaster.

Disassembly sequence planning using component-joint graph and ant colony optimization

Disassembly sequence planning is an important step of mechanical maintenance. This article presents an integrated study about the generation and optimizing algorithm of the disassembly sequence. Mechanical products are divided into two categories of components and connectors. The article uses component-joint graph to represent assembly constraints, including the incidence constraints are represented by incidence matrix and the interference constraints are represented by interference constraints. The inspiring factor and pheromone matrix are calculated according to assembly constraints. Then the ant generates its own disassembly sequences one by one and updates the inspiring factor and pheromone matrix. After all iterations, the best disassembly sequence planning of components and connectors are given. Finally, an application instance of the disassembly sequence of the jack is presented to illustrate the validity of this method.

Enzymatic self-assembly/disassembly turns “ON”/“OFF” the mimetic hydrolytic activity of histidine nanofibers

Mimetic enzymes are devised as alternates or supplements of natural enzymes in broad fields but regulating their activities in a switchable manner remains challenging.Herein,we proposed an enzymatic self-assembly/disassembly strategy to address this issue.A peptide molecule Nap FFEYIH(YH) was rationally designed which,after self-assembling into nanofibers,lined up the histidine moieties to form active hydrolysis centers for mimicking hydrolase activity.Enzymatic dephosphorylation of Nap FFEYp IH(Yp H) by alkaline phosphatase to yield YH also turned “ON” the hydrolase activity.In turn,phosphorylation of YH by phosphokinase epidermal growth factor receptor to yield Yp H disassembled the nanofibers and thus turned the activity “OFF”.As such,the “ON”/“OFF” of the mimetic hydrolase activities could be regulated under physiological conditions through ALP/EGFR-mediated self-assembly/disassembly of histidine nanofibers.This work provides a feasible strategy for the on-demand fabrication of artificial enzymes with controllable and superior activities.

Recent Advances in Activatable Probes for Molecular Imaging by Stimuli-Controlled Disassembly

Comprehensive Summary,Stimuli-controlled disassembly process has shown promise to direct delivery of probes and/or spatial-temporally control imaging signals for molecular imaging in vivo.Via the disassembly process,well defined nanoprobes with a stimulus-responsive moiety can be controllably converted into small-molecular imaging agents in response to a stimulus,leading to a switch in imaging signals.Moreover,the on-site released small-molecule probes could enhance penetration into the deep tissue for improved imaging of deep-seated molecular targets.Therefore,such a stimuli-controllable disassembly approach has been widely utilized to build activatable molecular imaging probes for the noninvasive detection of various molecular targets in living subjects.In this review article,we first briefly introduce the general principle of stimuli-controlled disassembly.We then summarize the activatable probes based on different internal or external stimulus that has been utilized to control disassembly process.Activatable probes by using multiple stimuli to control cascaded in situ self-assembly and disassembly processes are also discussed.Finally,we close with a conclusion of current challenges and perspective in this field.

GPU Accelerated Real-Time Collision Handling in Virtual Disassembly

Previous collision detection methods for virtual disassembly mainly detect collisions at discrete time intervals and use oriented bounding boxes to speed up the process. However, these discrete methods cannot guarantee no penetration occurs when the components move. Meanwhile, because some of the components are embedded into each other, these components cannot be separated in the subsequent process. To solve these problems, we propose an approach for real-time collision handling by utilizing the computational power of modern GPUs. First we present a novel GPU-based collision handling framework for virtual disassembly. Second we use a collision-streams based continuous collision detection to guarantee no collision missed. Finally we introduce a triangle intersection detection algorithm to solve the problem that collision cannot be detected when the components are embedded into each other at the initial configuration. The experimental results show that our method can improve the overall performance of collision detection and achieve real-time simulation.

A Discrete Bat Algorithm for Disassembly Sequence Planning

Based on the bat algorithm(BA), this paper proposes a discrete BA(DBA) approach to optimize the disassembly sequence planning(DSP) problem, for the purpose of obtaining an optimum disassembly sequence(ODS) of a product with a high degree of automation and guiding maintenance operation. The BA for solving continuous problems is introduced, and combining with mathematical formulations, the BA is reformed to be the DBA for DSP problems. The fitness function model(FFM) is built to evaluate the quality of disassembly sequences. The optimization performance of the DBA is tested and verified by an application case, and the DBA is compared with the genetic algorithm(GA), particle swarm optimization(PSO) algorithm and differential mutation BA(DMBA). Numerical experiments show that the proposed DBA has a better optimization capability and provides more accurate solutions than the other three algorithms.

On-demand assembly of polymeric nanoparticles for longer-blood-circulation and disassembly in tumor for boosting sonodynamic therapy

Sonodynamic therapy (SDT) is one of the promising strategies for tumor therapy, but its application is usually hindered by fast clearance in blood-circulation, abnormal tumor microenvironment, and inefficient generation of reactive oxygen species. To solve these problems, we proposed an on-demand assembly-disassembly strategy, where the assembly is favorable for longer-blood-circulation and then the disassembly in tumor is favorable for boosting SDT. Hematoporphyrin monomethyl ether (HMME) as the model of organic sonosensitizers were conjugated with hyaluronic acid (HA). Then HA-HMME was mixed with catalase (CAT) and assembled into polymeric nanoparticles (CAT@HA-HMME NPs) with size of ~80 nm. CAT@HA-HMME NPs exhibit good biocompatibility and a longer blood half-time (t1/2 = 4.17 h) which is obviously longer than that (~0.82 h) of HMME molecules. After HA receptor-mediated endocytosis of cancer cells, CAT@HA-HMME NPs can be cleaved by endogenous hyaluronidase, resulting in the on-demand disassembly in tumor to release HA-HMME molecules and CAT. The CAT catalyzes the endogenous H_(2)O_(2) into O_(2) to relieve the hypoxic microenvironment, and the released HA-HMME exhibits a higher ROS generation ability, greatly boosting SDT for the inhibition of tumor growth. Therefore, the on-demand assembly-disassembly strategy may provide some insight in the design and development of nanoagents for tumor therapy.

Performance evaluation of waste electrical and electronic equipment disassembly layout configurations using simulation

Recycling of waste electrical and electronic equipment （WEEE） is crucially important since it handles hazardous waste according to ever tightening laws and regulations and it adds benefits to economy and sustainable environment. Disassembly is one of the most important processes performed during the recovery of WEEE. The overall goal of disassembly is to maximize the retrieval of various metals and plastics contained in WEEE in order to reduce their negative effects on human health and environmental sustainability and to increase economic gains. This study aims to evaluate alternative layout configurations for WEEE disassembly systems （WDS）. In this context, various configurations were compared in terms of pre-defined performance criteria, such as the total number of disassembled WEEE and the total revenue from sales, using simulation models. The results of this study show that the perfomaance of a WDS was significantly affected by output transfer systems along with the specialization of operators on certain types of WEEE.

pH-Sensitive assembly/disassembly gold nanoparticles with the potential of tumor diagnosis and treatment

Due to the ability to combine the separately unique characteristics of assembled and disassembled nanoparticles(NPs), the stimuli-responsive self-assembly of NPs has attracted considerable interest in functional material applications especially biomaterials. Here we demonstrate a facile and versatile approach to regulate the self-assembly process and transition pH of Au NPs by fine-tuning the co-modified pH-responsive compounds and poly(ethylene glycol)(PEG). Importantly the transition pH(ΔpH=0.4) of the system can be predetermined in the range of 8.2–5.8(assembled to disassembled) and 8.2–4.2(disassembled to assembled), which ideally covers the pH of normal tissue, tumor tissue milieu and organelles. The results of fluorescence imaging, Raman spectroscopy and photothermal conversion of the stimuli-responsive Au NPs shows the potential application for tumor specificity theranostics. In a nutshell this study provides a useful toolkit to design tumor-activatable self-assembled NPs with high specificity and universality.