Chuyu Tang, Genliang Chen, Hao Wang and Yangfan Yu
Hull block assembly is a vital task in ship construction. It is necessary to obtain the actual poses of the assembly features to guide further block alignment. Traditional methods…
Abstract
Purpose
Hull block assembly is a vital task in ship construction. It is necessary to obtain the actual poses of the assembly features to guide further block alignment. Traditional methods use single-point measurement, which is time-consuming and may lead to loss of key information. Thus, large-scale scanning is introduced for data acquisition, and this paper aims to provide a precise and robust method for retrieving poses based on point set registration.
Design/methodology/approach
The main problem of point registration is to find the correct transformation between the model and the scene. In this paper, a vote framework based on a new point pair feature is used to calculate the transformation. First, a special edge indicator for multiplate objects is proposed to determine the edges. Subsequently, pair features with an edge description are noted for every point. Finally, a voting scheme based on agglomerative clustering is implemented to determine the optimal transformation.
Findings
The proposed method not only improves registration efficiency but also maintains high accuracy compared to several commonly used approaches. In particular, for objects composed of plates, the results of pose estimation are more promising because of the compact pair feature. The multiple ship longitudinal localization experiment validates the effectiveness in real scan applications.
Originality/value
The proposed edge description performs a better detection for the edges of multiplate objects. The pair feature incorporating the edge indicator is more discriminative than the original template, resulting in better robustness to outliers, noise and occlusions.
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Yangfan Li, Yingjie Zhang, Lin Zhang and Bochao Dai
The purpose of this paper is to analyze the changes in its importance due to the maintenance and repair of components.
Abstract
Purpose
The purpose of this paper is to analyze the changes in its importance due to the maintenance and repair of components.
Design/methodology/approach
In this paper, a concept of time-varying importance measure is proposed to solve the problem of component importance change caused by maintenance. When the system is broken-down, the probability difference between the component works well after repairing and the component break down before repairing is solved, this difference is measured as an index of time-varying importance method. Then, the approach has been verified by the CNC machine tool.
Findings
The paper provides a method to analyze the importance of changes of components in the system due to maintenance. The time-varying importance measure can evaluate the component importance anytime during its whole life span, and it has the ability to find out the most responsible component for a system failure in the actual production process. What is more, it provides guidance for the next maintenance work.
Originality/value
The proposed method can guide the next maintenance time according to the change of component performance caused by each maintenance activity of the manufacturing system, and avoid the waste of resources caused by repeated maintenance.
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Auxiliary power system is an indispensable part of the train; the auxiliary systems of both electric locomotives and EMUs mainly are powered by one of the two ways, which are…
Abstract
Purpose
Auxiliary power system is an indispensable part of the train; the auxiliary systems of both electric locomotives and EMUs mainly are powered by one of the two ways, which are either from auxiliary windings of traction transformers or from DC-link voltage of traction converters. Powered by DC-link voltage of traction converters, the auxiliary systems were maintained of uninterruptable power supply with energy from electric braking. Meanwhile, powered by traction transformers, the auxiliary systems were always out of power while passing the neutral section of power supply grid and control system is powered by battery at this time.
Design/methodology/approach
Uninterrupted power supply of auxiliary power system powered by auxiliary winding of traction transformer was studied. Failure reasons why previous solutions cannot be realized are analyzed. An uninterruptable power supply scheme for the auxiliary systems powered by auxiliary windings of traction transformers is proposed in this paper. The validity of the proposed scheme is verified by simulation and experimental results and on-site operation of an upgraded HXD3C type locomotive. This scheme is attractive for upgrading practical locomotives with the auxiliary systems powered by auxiliary windings of traction transformers.
Findings
This scheme regenerates braking power supplied to auxiliary windings of traction transformers while a locomotive runs in the neutral section of the power supply grid. Control objectives of uninterrupted power supply technology are proposed, which are no overvoltage, no overcurrent and uninterrupted power supply.
Originality/value
The control strategies of the scheme ensure both overvoltage free and inrush current free when a locomotive enters or leaves the neutral section. Furthermore, this scheme is cost low by employing updated control strategy of software and add both the two current sensors and two connection wires of hardware.
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Mohanraj R., Abdul Basith S. N., Chandru S, Gowtham D and Pradeep Kumar M
Wire arc additive manufacturing (WAAM) is one of the most researched and fastest-growing AM technique because of its capability to produce larger components with medium…
Abstract
Purpose
Wire arc additive manufacturing (WAAM) is one of the most researched and fastest-growing AM technique because of its capability to produce larger components with medium complexity. In recent times, the use of WAAM process has been increased because of its ability to produce complex components economically when compared with other AM techniques. The purpose of this study is to investigate the capabilities of wire arc additive manufacturing (WAAM), which has emerged as a recognized method for fabricating larger components with complex geometries.
Design/methodology/approach
This paper provides a review of process parameters for optimizing and analyzing mechanical properties, hardness, microstructure and corrosion behavior achieved through various WAAM-based techniques.
Findings
Limited analysis exists regarding the mechanical properties of various orientations of Inconel 625 alloy. Moreover, there is a lack of studies concerning the corrosion behavior of Inconel 625 alloy fabricated using WAAM.
Originality/value
The review identifies that the formation of intermetallic phases reduces the desirability of mechanical properties and corrosion resistance of WAAM-fabricated Inconel 625 alloy. Additionally, the study reported notable results obtained by various research studies and the improvements to be achieved in the future.
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Rio Jati Kusuma, Desty Ervira Puspaningtyas and Puspita Mardika Sari
The downstream insulin signaling, such as phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) pathway, is an important step for skeletal glucose disposal through the…
Abstract
Purpose
The downstream insulin signaling, such as phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) pathway, is an important step for skeletal glucose disposal through the translocation of glucose transporter (GLUT)-4. In addition, the master of energy regulator adenosine monophosphate-activated kinase (AMPK) is also involved in GLUT-4 translocation, independent from the PI3K/Akt pathway. Fermented cassava tuber or gatot is a traditional food from Indonesia with antihyperglycemic properties. However, the molecular mechanism leading to this effect is unclear. Therefore, this paper aims to evaluate whether the antidiabetic activity of gatot is through PI3K/Akt dependent or AMPK pathway.
Design/methodology/approach
Diabetes mellitus was induced in 20 male Wistar rats by intraperitoneal injection of 65 mg/kg body weight streptozotocin and 230 mg/kg body weight nicotinamide. Diabetic rats were randomly allocated into four groups; negative control, positive control (metformin 100 mg/kg body weight), fermented cassava diet replacing 50% of carbohydrate (FC-50) and 100% of carbohydrate (FC-100) in the diet. Serum glucose, insulin and lipid profile were analyzed before and after four weeks of intervention. Genes expression of PI3K subunit alpha, PI3K subunit beta, PI3K regulatory subunit, Akt and AMPK were analyzed using real time polymerase chain reaction (PCR). GLUT-4 protein expression was performed using immunohistochemistry.
Findings
There is a significant difference (p = 0.000) in serum glucose, insulin, total cholesterol, triglyceride, high density lipoprotein (HDL)-cholesterol and LDL-cholesterol between groups. Skeletal AMPK gene expression was higher and significantly different between FC-100 (p = 0.006) and healthy control groups. No significant difference was observed in the messenger ribonucleic acid (mRNA) expression of the PI3K/Akt pathway among groups. GLUT-4 expression was highly expressed in a positive control group followed by FC-100.
Research limitations/implications
This paper did not characterize the bioactive component that is responsible for increasing mRNA expression of AMPK. This paper also did not analyze the phosphorylation of PI3K/Akt and AMPK that are important in activating the protein.
Originality/value
To the best of the authors’ knowledge, this is the first study that showed the antidiabetic activity of traditional fermented food is through AMPK-dependent activity.
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Rafiq Asghar, Faisal Rehman, Ali Aman, Kashif Iqbal and Agha Ali Nawaz
The purpose of this paper is to investigate and minimize the printing-related defects in the surface mount assembly (SMA) process.
Abstract
Purpose
The purpose of this paper is to investigate and minimize the printing-related defects in the surface mount assembly (SMA) process.
Design/methodology/approach
This paper uses an experimental approach to explore process parameter and printing defects during the SMA process. Increasing printing performance, various practices of solder paste (Ag3.0/Cu0.5/Sn) storage and handling are suggested. Lopsided paste problem is studied by varying squeegee pressure and the results are presented. Unfilled pads problems are observed for ball grid array (BGA) and quad flat package (QFP) which is mitigated by proper force tuning. In this paper, a comparative study is conducted which evaluates the manifestation of printing offset due to low-grade stencil. The input/output (I/O) boards were oxidized when the relative humidity was maintained beyond 70 per cent for more than 8 h. This pad oxidation problem is overcome by proper printed circuit board (PCB) handling procedures. When the unoptimized line is used, the paste wedged in the stencil and influences the performance of the screen printer, for this reason, an optimized line is proposed that minimize the printing defects.
Findings
The key findings are as follows: in the SMA process, printing quality is directly associated with solder paste quality. Experimentally, it is observed that a considerable variance in solder deposition occurred when the front and rear squeegee have different configurations. High-grade and unsoiled stencil results in superior paste deposition and less distinction. Insufficient solder paste and bridge problems also occur in printing when PCB pads are oxidized. Optimized line resolves solder paste clog issues, associated with stencil’s aperture. The cooling arrangement on the conveyor, after reflow, explicates hot jig problem. Control environmental conditions minimized static charges and printing defects.
Originality/value
The preceding studies emphasis mostly on the squeegee pressure, while other important parameters are not completely investigated. Moreover, it is very imperative to concurrently measure all parameters while varying the environmental conditions. This study highlights and provides an experimental approach to various PCB printing defects, and a comparative study has been conducted that concurrently measure all process parameters.
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The purpose of this paper is to present an integrated data-driven framework for processing and analyzing large-scale vehicle maintenance records to get more comprehensive…
Abstract
Purpose
The purpose of this paper is to present an integrated data-driven framework for processing and analyzing large-scale vehicle maintenance records to get more comprehensive understanding on vehicle quality.
Design/methodology/approach
We propose a framework for vehicle quality analysis based on maintenance record mining and Bayesian Network. It includes the development of a comprehensive dictionary for efficient classification of maintenance items, and the establishment of a Bayesian Network model for vehicle quality evaluation. The vehicle design parameters, price and performance of functional systems are modeled as node variables in the Bayesian Network. Bayesian Network reasoning is then used to analyze the influence of these nodes on vehicle quality and their respective importance.
Findings
A case study using the maintenance records of 74 sport utility vehicle (SUV) models is presented to demonstrate the validity of the proposed framework. Our results reveal that factors such as vehicle size, chassis issues and engine displacement, can affect the chance of vehicle failures and accidents. The influence of factors such as price and performance of engine and chassis show explicit regional differences.
Originality/value
Previous research usually focuses on limited maintenance records from a single vehicle producer, while our proposed framework enables efficient and systematic processing of larger-scale maintenance records for vehicle quality analysis, which can support auto companies, consumers and regulators to make better decisions in purchase choice-making, vehicle design and market regulation.