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This study aims to find technologically important patent identification methods and indicators early and efficiently to grasp the technical qualitative level of patents, which are output indicators of research and development (R&D) results.

This paper reports on two methods for distinguishing important patents and the indicators obtained from those methods. One of the discrimination methods is Heckman's two-step estimation procedure. The second method is to find the centrality of each patent by network analysis of the citation relationship between publications and to find the importance from the magnitude of the centrality value.

In Heckman's analysis, the number of citations within three years after publication and the applicant's right acquisition/maintenance motivation index had positive effects on patent importance. The discriminative indicators of important patents by network analysis were degree centrality, mediation centrality, proximity centrality and transit values in the aggregated subnetworks. These two analytical methods are in a relationship that can complement each other's shortcomings. To efficiently evaluate the qualitative importance of patents, it is recommended to use these two methods together.

The indicators of important technical patents might change depending on the technical field. Future studies can apply this research to multiple technical fields to improve robustness and to construct an algorithm that can efficiently evaluate the quality of patents.

This study's results can be useful for grasping the patent position of the company or competitors numerically and for quantitatively evaluating the quality of R&D activities. Furthermore, it is possible to streamline the routine for an exploratory search of a huge number of patents. For example, it could be useful for detecting changes in the paradigm of specific technical knowledge, evolving the genealogy of technical knowledge and creating patent maps for new R&D. These methods greatly increase the effectiveness of technical knowledge information, which is the basis of R&D. In addition, the results of this study can help in evaluating patented assets.

This study confirmed the development process of technical knowledge. It is a fact that sharing, sympathy and mutual trust for technical issues and technical values are created among professional engineers and researchers inside and outside the organization, and their preferences and interactions develop and expand technical knowledge. Understanding the process of development and the evolution of this technical knowledge gives hints, such as expanding the discretionary power of engineers and researchers regarding corporate secrets, or reviewing the balance between control and independence, to solve Japanese management problems, which are often closed and monetized in R&D activities.

This study presents a scoring of the technical significance of patents by combining the two analytical methods. In addition, there are proposals as a method for detecting changes in the genealogy and paradigm of technical knowledge. As an analysis method, it is a new proposal that has never existed before.

To review the capabilities of a new method of welding aluminium sheets for car body construction.

Describes the friction spot joining technique, and how it differs from friction stir welding. Describes the tests carried out at the University of Warwick to compare this with other aluminium sheet joining techniques.

Compared with resistance spot welding, this technique is simple, and physically and electromagnetically clean. Its low energy requirement per joint and low running costs give it advantages in joining thin materials, and eventual recycling is much easier than with self‐piercing riveting joints.

Describes the motivation behind the continuing development of an all‐aluminium joining technique, and compares spot friction joining with self‐pierce riveting and resistance spot welding.

This study aims to enable robotic friction stir welding (FSW) in practice. The use of robots has hitherto been limited, because of the large contact forces necessary for FSW. These forces are detrimental for the position accuracy of the robot. In this context, it is not sufficient to rely on the robot’s internal sensors for positioning. This paper describes and evaluates a new method for overcoming this issue.

A closed-loop robot control system for seam-tracking control and force control, running and recording data in real-time operation, was developed. The complete system was experimentally verified. External position measurements were obtained from a laser seam tracker and deviations from the seam were compensated for, using feedback of the measurements to a position controller.

The proposed system was shown to be working well in overcoming position error. The system is flexible and reconfigurable for batch and short production runs. The welds were free of defects and had beneficial mechanical properties.

In the experiments, the laser seam tracker was used both for control feedback and for performance evaluation. For evaluation, it would be better to use yet another external sensor for position measurements, providing ground truth.

These results imply that robotic FSW is practically realizable, with the accuracy requirements fulfilled.

The method proposed in this research yields very accurate seam tracking as compared to previous research. This accuracy, in turn, is crucial for the quality of the resulting material.

This paper aims to summarize the microstructure characterization of parts that were produced using a hybrid manufacturing process consisting of laser metal deposition (LMD) and friction stir processing (FSP). This research was conducted to investigate the evolution of the microstructure following FSP and LMD and to study the possibility of producing or repairing parts with a forged-like microstructure using this hybrid technique.

The microstructure of the nugget regions obtained in the substrate weld, stir over deposit and deposit over stir experiments was investigated.

Highly refined grain size in the order of 1-2 μm was observed where FSP was performed over laser-deposited Ti–6Al–4V. Large equiaxed grains were observed in the experiment where subsequent deposition was carried over the stir. A decreasing grain size was also observed in the dilution zone (DZ) inside the nugget from the stir surface to the bottom of the DZ.

A highly refined microstructure formed from FSP is able to increase the fatigue life by delaying the fatigue crack initiation. Peters et al. (1980) reported that reducing the grain size from 12-15 μm to 1-2 μm in an equiaxed Ti–6Al–4V alloy corresponded with about 25 per cent increase in fatigue strengths at 10,000,000 cycles.

This proposed technical approach is a novel and effective method to produce forged-like parts using a metal additive manufacturing process.

THE possibility of explosive cladding was first recognised in 1957, when it was noted in explosive forming that if a metal die was employed and an excessive charge was used then the metal sheet which was being formed became welded to the die. Since that time numerous papers have been published, for instance Davenport and Duvall (Ref. 1), Pearson (Ref. 2), Holtzman and Ruderhausen (Ref. 3), Boes (Ref. 4), and Bahrani and Crossland (Ref. 5) to mention but a few. All the early work was devoted to the application of cladding, and it is only during the last two or three years that the applicability of the process to tube welding, lap welding, welding of tees has been mentioned. At the present time the main potential fields of application are to the cladding of dissimilar metals over large areas and the welding of tubes to tube plates.