Assembly process case matching based on a multilevel assembly ontology method

Purpose The purpose of this study is to achieve accurate matching of new process cases to historical process cases and then complete the reuse of process knowledge and assembly experience. Design/methodology/approach By integrating case-based reasoning (CBR) and ontology technology, a multilevel assembly ontology is proposed. Under the general framework, the knowledge of the assembly domain is described hierarchically and associatively. On this basis, an assembly process case matching method is developed. Findings By fully considering the influence of ontology individual, case structure, assembly scenario and introducing the correction factor, the similarity between non-correlated parts is significantly reduced. Compared with the Triple Matching-Distance Model, the degree of distinction and accuracy of parts matching are effectively improved. Finally, the usefulness of the proposed method is also proved by the matching of four practical assembly cases of precision components. Originality/value The process knowledge in historical assembly cases is expressed in a specific ontology framework, which makes up for the defects of the traditional CBR model. The proposed matching method takes into account all aspects of ontology construction and can be used well in cross-ontology similarity calculations.

An Approach to Variation Simulation of Final Aircraft Assembly with Presence of Sealant

The article discusses the process of aeronautical structure assembly in the presence of a sealant between the parts to be joined. An attempt to estimate the influence of sealant on assembly quality in terms of variation analysis is presented. The sealant is considered as a highly viscous liquid that is applied to the surfaces of the assembled parts before the start of final assembly. The modeling approach is based on simulation of two-way coupled fluid-structure interaction between fluid sealant and compliant structural parts. Reynolds lubrication approximation is used in the fluid dynamics problem and variational formulation of contact problem combined with static condensation is used in the structural one. The joining of two aircraft panels is used as a numerical test for demonstration of developed approach. Various phenomena connected with the presence of sealant are demonstrated. In particular, the difference in the fastener loosening due to sealant flow between different types of fasteners is investigated. Results of variation simulation show that presence of sealant should be considered among determining factors in the analysis of assembly quality.

Development of Injectable Hydroxyapatite/2-(dimethylamino)Ethyl Methacrylate/Polyvinylpyrrolidone Aqua-Hydrogel System to Repair of the Shoulder Joint Head for Hemiarthroplasty

This study aimed to develop osteogenic structure assembly for modular bone treatment presentations, effect of 2-(dimethylamino)ethyl methacrylate and polyvinyl pyrrolidone combination as cell adhesive molecule with hydroxyapatite-based composite as osteoconductive constituent was inspected on bone fracture repair. The prepared injectable composite hydrogel showed significantly improved mechanical stability. The ternary composite gel was characterized for functional group modifications and chemical interactions using Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Moreover, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analyses were performed to observe surface appearances of the hydrogel. The hydroxyapatite/2-(dimethylamino)ethyl methacrylate/poly-N-vinyl-2-pyrrolidone hydrogel played key role in supporting osteoblastic cell spread due to their bioactivity and strength abilities. The present findings revealed the significance of hydroxyapatite concentration on proliferation and osteogenic purpose of the cells. The developed performances of hydrogel have been improved cell proliferation and functions to repair bone fracture.

Development of Virtual Simulation Experimental Software of Marine Platform Structure

Due to the harsh offshore exploitation environment, students are unable to conduct field investigation in offshore platforms. In this scenario, virtual simulation is an effective way to solve this problem. This paper introduces in detail a Virtual Simulation Experimental Software of Marine Platform Structure, which is closely integrated with the course content and engineering reality. Through the operation and learning of platform site selection, platform structure assembly, platform structure display, can realize the students' knowledge of platform structure composition mastery, and at the same time improve the students' participation and motivation. In addition, the system can automatically generate the experiment report and give the operation score reference to realize the teacher's quality control of the experiment course.

Weaving of bacterial cellulose by the Bcs secretion systems

Cellulose is the most abundant biological compound on Earth and while it is the predominant building constituent of plants, it is also a key extracellular matrix component in many diverse bacterial species. While bacterial cellulose was first described in the 19th century, it was not until this last decade that a string of structural works provided insights into how the cellulose synthase BcsA, assisted by its inner-membrane partner BcsB, senses c-di-GMP to simultaneously polymerize its substrate and extrude the nascent polysaccharide across the inner bacterial membrane. It is now established that bacterial cellulose can be produced by several distinct types of cellulose secretion systems and that in addition to BcsAB, they can feature multiple accessory subunits, often indispensable for polysaccharide production. Importantly, the last years mark significant progress in our understanding not only of cellulose polymerization per se, but also of the bigger picture of bacterial signaling, secretion system assembly, biofilm formation and host tissue colonization, as well as of structural and functional parallels of this dominant biosynthetic process between the bacterial and eukaryotic domains of life. Here we review current mechanistic knowledge on bacterial cellulose secretion with focus on the structure, assembly and cooperativity of Bcs secretion system components.

Shallow Water Subsea Well Drilling and Completion Utilizing Jack Up Rig at Natuna Sea Block

In 2019, Premier Oil Indonesia commenced drilling campaign to complete 4 development wells consist of 3 subsea development wells and 1 platform well at Natuna Sea Block with water depth 260ft - 280ft. To optimize the mobilization and demobilization cost, one single Jack Up rig was selected to complete those 4 wells. The Jack Up rig require several modifications to enable drilling and completing subsea wells. The Jack Up rig is equipped only with surface BOP stack; therefore, 16” HP riser is utilized to drill reservoir section then a Suspended Texas Deck (STD) was required as means to suspend the weight in order to hang 16” HP riser stack and also it is designed to take the full BOP weight in the event the secondary BOP tensioner fail. A modification work was also performed on Conductor Tensioner Platform (CTP) to extend it to accommodate Subsea Tree temporary storing of Subsea Tree complete with Tree Running Tool (TRT) for inspection and preparation prior to subsea deployment. On the other hand, Subsea Tree has Protection Structure Assembly (PSA) has the biggest dimension among other subsea equipment which leaving only option to be deployed by TDS directly from supply vessel to the wellhead using ROV-friendly lifting bridle arrangement. The drilling campaign has successfully completed and met drilling objectives without major safety case. It is proven that with collaborative engineering works involving company, rig contractor and third party contractors enabling the success of subsea drilling and completion campaign in shallow water at Natuna Sea Block using Jack-up rig. The lesson learned was established upon completing drilling the 1st well then applied to next well resulting significant time improvement to complete the well from 52 days to become only 35 days, noting that these 2 wells have similar drilling and completion profile.

Improving fragment-based ab initio protein structure assembly using low-accuracy contact-map predictions

Sequence-based contact prediction has shown considerable promise in assisting non-homologous structure modeling, but it often requires many homologous sequences and a sufficient number of correct contacts to achieve correct folds. Here, we developed a method, C-QUARK, that integrates multiple deep-learning and coevolution-based contact-maps to guide the replica-exchange Monte Carlo fragment assembly simulations. The method was tested on 247 non-redundant proteins, where C-QUARK could fold 75% of the cases with TM-scores (template-modeling scores) ≥0.5, which was 2.6 times more than that achieved by QUARK. For the 59 cases that had either low contact accuracy or few homologous sequences, C-QUARK correctly folded 6 times more proteins than other contact-based folding methods. C-QUARK was also tested on 64 free-modeling targets from the 13th CASP (critical assessment of protein structure prediction) experiment and had an average GDT_TS (global distance test) score that was 5% higher than the best CASP predictors. These data demonstrate, in a robust manner, the progress in modeling non-homologous protein structures using low-accuracy and sparse contact-map predictions.

A subcellular biochemical model for T6SS dynamics reveals winning competitive strategies

The Type VI secretion system (T6SS) is a broadly distributed interbacterial weapon that can be used to eliminate competing bacterial populations. Although unarmed target populations are typically used to study T6SS function, bacteria most likely encounter other T6SS-armed competitors in nature. The outcome of such battles is not well understood, neither is the connection between the outcomes with the subcellular details of the T6SS. Here, we incorporated new biological data derived from natural competitors of Vibrio fischeri light organ symbionts to build a biochemical model for T6SS function at the single cell level. The model accounts for activation of structure formation, structure assembly, and deployment. By developing an integrated agent-based model (IABM) that incorporates strain-specific T6SS parameters, we replicated outcomes of biological competitions, validating our approach. We used the IABM to isolate and manipulate strain-specific physiological differences between competitors, in a way that is not possible using biological samples, to identify winning strategies for T6SS-armed populations. We found that a tipping point exists where the cost of building more T6SS weapons outweighs their protective ability. Furthermore, we found that competitions between a T6SS-armed population and a unarmed target had different outcomes dependent on the geometry of the battlefield: target cells survived at the edges of a range expansion scenario where unlimited territory could be claimed, while competitions within a confined space, much like the light organ crypts where natural V. fischeri compete, resulted in the rapid elimination of the unarmed competitor.