Fusion Area Research Articles

Investigations on laser beam welding of thin aluminum foils with additional filler wire

Nowadays, battery-electric drives and energy storage are elected to be the future technologies. In the manufacturing of parts for electric applications, laser beam welding is an appropriate and favorable welding method. The characteristics of high welding speed, local heat input, and the contact-free process allow efficient and automatable processes. For electrodes, mainly copper and aluminum are used. Many foils with thicknesses of an area of 10 μm have to be connected to create battery cells. Different than expected, aluminum is a more challenging material to produce than others. Pore formation is also extended in aluminum due to the presence of air between the foils. The connecting cross section is thereby reduced. Furthermore, there is detachment in the fusion area and a high weld seam undercut. In addition to insufficient clamping, a lack of material reduces strength and, thus, usability. In the research presented here, the use of aluminum filler wire (AA 1050A) and shielding gas are investigated for the application of welding 40 aluminum foils (AA 1050A) with a thickness of 15 μm to an aluminum sheet with a thickness of 2 mm using infrared laser beam wavelength. The aims of the process development are welds with high connection widths and high quality as well as reproducibility to provide excellent mechanical properties and the highest electrical conductivity.

Influence of laser beam scanning pattern and polar angle on the fatigue behavior of additively manufactured specimens made of steel 316L

While Laser Powder Bed Fusion (LPBF) is a popular, rapidly advancing field of research, a comprehensive or deeper understanding of the mechanical, especially fatigue, properties of steels has not yet been fully achieved. In this work, a deeper investigation on the microstructural load capacity, critical defect size distribution and defect tolerance of fatigue performance of the commonly used 316L austenitic steel were performed. The 316L parts were generated via LPBF with three different scan patterns and polar angles. Resulting porosities were measured with Archimedes' method and cross section scanning with optical microscopy. To understand the relation of process parameters, microstructure and mechanical behaviors, the microstructure and mechanical properties were studied. Fatigue damage origins and fracture mechanisms were investigated. Results showed that apart from comparable hardness to the conventional steel, tensile properties (except Young's modulus) are slightly worse than the conventional values, owing to the fact that the presence of pores and inclusions promote earlier plastic deformations and ductile fracture. The fatigue strength is inferior compared to the conventional steel and most samples failed from lack of fusion. The surfaces of lack of fusion areas, triggering fatigue failure, are either smooth or show parallel lines. The different scan strategies lead to no big difference in the microstructures except the size of the largest lack of fusion area. The polar angles determine the orientations of lack of fusion to the loading axis and result in different sizes of fatigue triggering defects and deteriorate the matrix load capacity to different extents. Spherical pores within a certain range have limited impact. Parallel simulations confirm the defect tolerance determined by the morphology and critical size on the fatigue strength.

992 Pioneering Robot-Assisted Spine Surgery in the United Kingdom

Abstract Aim The placement of a large interbody implant allows for a larger fusion area. Retroperitoneal approaches, like anterior, antero-lateral, and lateral fusion, facilitate the placement of these implants. At the same time, robot-navigation facilitate complex, minimally invasive spine surgery for posterior screw fixation. This is a single-surgeon, single-centre report on the experience of the first procedures ever performed for navigated robot-assisted spine surgery in the United Kingdom. Method Between October 2019 and May 2021, we identified 34 consecutive patients who underwent robot-assisted spine surgery. The demographic, intra-operative, and peri-operative data were reviewed. Results Of the 34 patients, 65 levels were treated in total (204 screws). 21 patients (60%) underwent single-level fixation, 14 of them (67%) were treated at the L5/S1 level, 3 at L3/L4, 3 at L4/L5 and 1 at L2/L3 level, 13 patients (40%) underwent multi-level fixation, with 4 of them treated for adult scoliosis. Eight patients underwent a supine ALALIF approach and one a lateral decubitus AL-ALIF, 7 had a pure ALIF approach, 8 patients underwent combined XLIF and AL-ALIF approach in a lateral decubitus, 6 underwent pure XLIF approach, 1 patient had previous TLIF surgery, and 3 patients underwent single position lateral surgery (lateral decubitus fusion and posterior screw fixation). Conclusions Minimally invasive spine surgery using robot-assisted navigation yields an improved level of accuracy, decreased radiation exposure, minimal muscle disruption, decreased blood loss, shorter operating theatre time, length of stay, and lower complication rates. Further follow-up of the patients treated will help compare the clinical outcomes with other techniques.

Medical Diagnosis with Multimodal Image Fusion Techniques

Image Fusion is an effective approach utilized to draw out all the significant information from the source images, which supports experts in evaluation and quick decision making. Multi modal medical image fusion produces a composite fused image utilizing various sources to improve quality and extract complementary information. It is extremely challenging to gather every piece of information needed using just one imaging method. Therefore, images obtained from different modalities are fused Additional clinical information can be gleaned through the fusion of several types of medical image pairings. This study's main aim is to present a thorough review of medical image fusion techniques which also covers steps in fusion process, levels of fusion, various imaging modalities with their pros and cons, and the major scientific difficulties encountered in the area of medical image fusion. This paper also summarizes the quality assessments fusion metrics. The various approaches used by image fusion algorithms that are presently available in the literature are classified into four broad categories i) Spatial fusion methods ii) Multiscale Decomposition based methods iii) Neural Network based methods and iv) Fuzzy Logic based methods. the benefits and pitfalls of the existing literature are explored and Future insights are suggested. Moreover, this study is anticipated to create a solid platform for the development of better fusion techniques in medical applications.

Strengthening of Al/Cu dissimilar joint due to complicated interface produced by pulsed TIG welding with a constricted nozzle

Al/Cu dissimilar welding is a key technology for weight reduction in fabricating high-functional products, however, conventional tungsten inert gas (TIG) welding is difficult to be applied due to a large fusion area. The constricted nozzle equipped inside the conventional TIG torch has been developed and can improve the position accuracy of tungsten electrode and arc plasma characteristics, moreover increase the heat input density. In this study, 0.5 mm-thick Al and Cu dissimilar sheets were butt welded using pulsed TIG welding with the constricted nozzle under two welding speed-current combinations of 50 mm/s-85 A and 100 mm/s-105 A. The 50 mm/s-85 A joint exhibited that Al and Cu mixed each other in the entire weld metal, containing two intermetallic compounds (IMC) of Al2Cu and Al4Cu9 mainly in the Al side. In contrast, both elements hardly mixed each other in the 100 mm/s-105 A weld metal and the interface exhibited hook-like shape at a nearly constant pitch, depending on the welding speed and pulse frequency. Consequently, the formation of IMC layers was limited. Based on the three-dimensional images reconstructed using a serial sectioning technique, the hook-shaped Al/Cu interface was also formed inside the weld metal. The mixed-zone volume per unit weld length of the 100 mm/s-105 A joint was estimated to be about 0.12 mm3/mm, and is much smaller than that of the 50 mm/s-85 A joint (0.97 mm3/mm). The average tensile strength of the 100 mm/s-105 A joint were higher than those of the 50 mm/s-85 A joint, suggesting that the hook-shaped Al/Cu interface together with the reduced mixed zone seems to increase the joint strength.

Radiographical Results of Adolescent Idiopathic Scoliosis with Major Curve at Proximal Thoracic Spine.

Adolescent idiopathic scoliosis (AIS) with a major curve at the main thoracic (MT) area is classified as Lenke type 1, 2, or 3 depending on the flexibility of the proximal thoracic (PT) curve and lumbar curve. No definite classification has been established for a major curve at the PT spine. The purpose of this study is to investigate the radiographic characteristics before and after correction surgery for AIS with a major curve at the PT area. This is a retrospective cohort study at a single academic institution. Twelve patients with a major curve at the PT spine participated in our study and followed for at least two years after surgery. We evaluated the pre- and postoperative Cobb angles of the curve, curve range, location of the apex, sagittal parameters, and shoulder balance-related parameters. All patients were treated by posterior correction and fusion surgery using pedicle screw constructs. The patients were classified as having a double-curve (DC) type, in which the MT curve was structural, or a single-curve (SC) type, in which the MT curve was corrected to less than 25° on supine side-bending films. The mean correction rates for the PT curve were favorable in both groups (DC, 65.7%±9.6%; SC, 39.2%±4.9%). The mean Cobb angle of the lumbar curve improved in the DC group (preoperative, 17.1°±4.0°; postoperative, 5.0°±4.2°) but deteriorated in the SC group (preoperative, 7.1°±1.2°; postoperative, 12.4°±4.4°) after surgery. We illustrated the postoperative radiographical changes of 12 consecutive patients with the major curve at the PT curve. Although posterior correction and fusion surgery corrected the PT curve satisfactorily in both DC and SC patients, the Cobb angle of the lumbar curve deteriorated after surgery in all SC patients. Surgeons need to pay attention to the fusion area, especially LIV, when operating the SC curve type.

Effect of substrate preheating on the microstructure and bending behavior of WC-Inconel 718 composite coating synthesized via laser directed energy deposition

In this study, a substrate is reinforced with WC/Inconel 718 composite coating via directed energy deposition (DED). During the DED, the substrate was preheated to 300 °C and 500 °C. The microstructural characteristics of the matrix, fusion area, and area around the WC particles were systematically investigated. The results showed that the depth of the transition zone at the interface of the deposited layer and substrate for preheating to 500 °C increased, enhancing the metallurgical bonding between the deposited layer and the substrate. Additionally, three different types of WC particle diffusion mechanisms were exhibited: (i) slight dissolution diffusion for non-preheating sample, (ii) dissolution-diffusion fragmentation for 300 °C-preheating sample, and (iii) disintegration and diffusion for 500 °C-preheating sample. In contrast, the effects of dispersion and solid solution strengthening are more pronounced than that of the microstructure coarsening caused by preheating, resulting in a higher hardness value of 384.0 HV0.1 (preheating at 300 °C) and 381.3 HV0.1 (preheating at 500 °C) compared to that of the non-preheated sample (358.9 HV0.1). Furthermore, the bending fracture of the WC/Inconel 718 composite layer exhibited typical pseudo-ductile behavior with premature fracture. Consequently, the highest bending strength occurred at preheating 500 °C, in which the maximum bending load and the displacement at the initial crack increased by 9.15% and 39.69%, respectively, compared with the non-preheated sample. Additionally, the fracture mechanism exhibited mainly intergranular fracture and less transgranular fracture.

Research on new technology of laser forging coupled arc welding of E690 marine steel

PurposeThe purpose of this study is to reduce the cracks, pores and unfused defects in arc welding, improve the crystalline structure of the weld, refine its grains and improve the mechanical properties.Design/methodology/approachTaking E690 marine steel as the research object, the experiment adopts a new process method of laser forging coupled arc welding. Welding for comparative experiments. Experiments show that the “V”-shaped groove arc welding process has a larger fusion area, but has pores, the arc current is 168 A, the arc voltage is 28 V and the welding speed is 600 mm/min.FindingsIt can be seen from tensile tests that the coupling welding process has the highest tensile strength and yield strength, 872 MPa and 692 MPa, respectively, and the fracture elongation is 29.29%. The single-beam laser forging coupled arc welding process has a distance of laser and wire of 6–8 mm, a laser wavelength of 1,064 nm and the highest weld fusion ratio. The microhardness test shows that the average hardness of single-beam laser forging in the weld zone is 487.54 HV, which is 10.30% higher than that of arc welding. The average hardness in the fusion zone is 788.08 HV, which is 14.52% higher than that of the arc welding process.Originality/valueThe originality of the experiment: proposed a new process method of coupling arc repair for offshore steel forging; adopted a new process method of simultaneous coupling of single-beam short-pulse laser, double-beam short-pulse laser and arc welding; and obtained effect of pulsed laser and arc composite repair on porosity and fusion of E690 marine steel welds.

Study on Trends and Predictions of Convergence in Cybersecurity Technology Using Machine Learning

<p>The indiscriminate convergence of technologies makes prediction difficult and can cause many difficulties in technology investment. This makes it difficult to choose capital investment and can induce excessive investment in inefficient technologies. Therefore, analyzing the trend of convergence technology and predicting a highly influential convergence area in the future can induce effective investment, and lead the highly influential technology to achieve great technological development. The purpose of this paper is to analyze technologies that are expected to have high influence in the future through prediction of major fusion areas and to present fusion areas that can be used as indicators of investment. The proposed mechanism selected four prominent journals in the security area and collected metadata to generate a dataset in terms of technological excellence and a dataset in terms of commercialization through patent metadata collection. Thereafter, a process of extracting a main keyword according to a topic from a metadata set by applying a Latent Dirichlet Allocation (LDA) is performed. The extracted topics and keywords are not related to topics and keywords of other years. Therefore, a dynamic topic model (DTM) is applied to analyze the trend of the extracted topics and perform prediction. DTM analyzes the topics in the fusion area classified by LDA and the trend of changing topics linked by year for each topic keyword. Finally, the association of the fusion region is analyzed to derive a fusion region with high influence. These results are believed to be used as an indicator of effective technology investment by providing a high impact area in the convergence area of cybersecurity.</p> <p> </p>

Research on Improved Multi-Channel Image Stitching Technology Based on Fast Algorithms

The image registration and fusion process of image stitching algorithms entails significant computational costs, and the use of robust stitching algorithms with good performance is limited in real-time applications on PCs (personal computers) and embedded systems. Fast image registration and fusion algorithms suffer from problems such as ghosting and dashed lines, resulting in suboptimal display effects on the stitching. Consequently, this study proposes a multi-channel image stitching approach based on fast image registration and fusion algorithms, which enhances the stitching effect on the basis of fast algorithms, thereby augmenting its potential for deployment in real-time applications. First, in the image registration stage, the gridded Binary Robust Invariant Scalable Keypoints (BRISK) method was used to improve the matching efficiency of feature points, and the Grid-based Motion Statistics (GMS) algorithm with a bidirectional rough matching method was used to improve the matching accuracy of feature points. Then, the optimal seam algorithm was used in the image fusion stage to obtain the seam line and construct the fusion area. The seam and transition areas were fused using the fade-in and fade-out weighting algorithm to obtain smooth and high-quality stitched images. The experimental results demonstrate the performance of our proposed method through an improvement in image registration and fusion metrics. We compared our approach with both the original algorithm and other existing methods and achieved significant improvements in eliminating stitching artifacts such as ghosting and discontinuities while maintaining the efficiency of fast algorithms.

In-situ 3D contour measurement for laser powder bed fusion based on phase guidance

In-situ layerwise imaging measurement of laser powder bed fusion (LPBF) provides a wealth of forming and defect data which enables monitoring of components quality and powder bed homogeneity. Using high-resolution camera layerwise imaging and image processing algorithms to monitor fusion area and powder bed geometric defects has been studied by many researchers, which successfully monitored the contours of components and evaluated their accuracy. However, research for the methods of in-situ 3D contour measurement or component edge warping identification is rare. In this study, a 3D contour measurement method combining gray intensity and phase difference is proposed, and its accuracy is verified by designed experiments. The results show that the high-precision of the 3D contours can be achieved by the constructed energy minimization function. This method can detect the deviations of common geometric features as well as warpage at LPBF component edges, and provides fundamental data for in-situ quality monitoring tools.

YOLOv7-RAR for Urban Vehicle Detection.

Aiming at the problems of high missed detection rates of the YOLOv7 algorithm for vehicle detection on urban roads, weak perception of small targets in perspective, and insufficient feature extraction, the YOLOv7-RAR recognition algorithm is proposed. The algorithm is improved from the following three directions based on YOLOv7. Firstly, in view of the insufficient nonlinear feature fusion of the original backbone network, the Res3Unit structure is used to reconstruct the backbone network of YOLOv7 to improve the ability of the network model architecture to obtain more nonlinear features. Secondly, in view of the problem that there are many interference backgrounds in urban roads and that the original network is weak in positioning targets such as vehicles, a plug-and-play hybrid attention mechanism module, ACmix, is added after the SPPCSPC layer of the backbone network to enhance the network's attention to vehicles and reduce the interference of other targets. Finally, aiming at the problem that the receptive field of the original network Narrows, with the deepening of the network model, leads to a high miss rate of small targets, the Gaussian receptive field scheme used in the RFLA (Gaussian-receptive-field-based label assignment) module is used at the connection between the feature fusion area and the detection head to improve the receptive field of the network model for small objects in the image. Combining the three improvement measures, the first letter of the name of each improvement measure is selected, and the improved algorithm is named the YOLOv7-RAR algorithm. Experiments show that on urban roads with crowded vehicles and different weather patterns, the average detection accuracy of the YOLOv7-RAR algorithm reaches 95.1%, which is 2.4% higher than that of the original algorithm; the AP50:90 performance is 12.6% higher than that of the original algorithm. The running speed of the YOLOv7-RAR algorithm reaches 96 FPS, which meets the real-time requirements of vehicle detection; hence, the algorithm can be better applied to vehicle detection.

Keyhole stability and surface quality during novel adjustable-ring mode laser (ARM) welding of aluminum alloy

Aims at keyhole instability and poor surface-quality in welding of aluminum alloy, a novel laser technology has been studied on welding of Al 6061. The novel laser beam consists of a ring part and a center part. Different power ratio of ring laser beam to center laser beam and different kind of laser beam welding experiments have been conducted, respectively. The keyhole stability and surface quality were analyzed by using a high-speed camera and a confocal sensor accordingly. Additionally, the energy absorption rate was studied by analyzing the penetration and fusion area of cross-section. Experimental results showed that the ring laser beam provided great stability on the center laser-induced keyhole in high-speed dual-mode ring/center laser welding of aluminum. The stability effects can be improved by increasing the ring power in dual-mode ring/center laser welding of aluminum alloy, and the stabilized effect would contribute to the high-surface quality on welding of aluminum alloy. Furthermore, the combination of ring laser and center laser (Gaussian laser) greatly improved the welding efficiency due to its synergistic effects on process status in the ARM laser welding process. This work provided a basic research to both scientist and engineer on the mechanism of ARM laser welding aluminum alloy.

Double side friction stir welding effect on mechanical properties and corrosion rate of aluminum alloy AA6061

Friction Stir Welding (FSW) is a solid-state welding method that has diffusion and different metal structures can blend well. Friction stir welding (FSW) has a weakness, one of which is the lack of flexibility the welding process is only carried out on one side of the plate being welded, so it is not applied on thick materials. Double side friction stir welding is a double working process in which the plate to be welded is subjected to friction from two tools on opposite sides. In the DS-FSW welding process, the dimensions and geometry of the tool and pin greatly affect the quality of the joint. This study to determine the mechanical properties and corrosion rate of Double side friction stir welding aluminum 6061 with variation rotation speed and axis of top and bottom tools. The results of this radiographic test can be seen that specimen 4 welded with variations in speed and tool position has defects in the form of incomplete fusion (IF). The results of microstructural observations showed that the heat caused by the welding process resulted in recrystallization in the form of fine grains in the stirring area and there was no phase change. The highest hardness value in the welding area is specimen B. The largest bending value at the 1G welding positions is specimen D, which is 41.86 MPa with a strain value of 13.23%, while the smallest value at the 4G welding position is specimen A, which is 38.18 MPa with a strain value of 5.03%. The fracture and crack surfaces showed that crack initiation, propagation and material stirring failure occurred in all test specimens, even though the impact test specimen was cut in a small area of Incomplete Fusion, but the test results showed that there was still a surface of the parent metal that had not been stirred. The corrosion test method uses three electrode cells with corrosion media as a substitute for seawater with a salinity of 3.5% NaCl, result of corrosion test is specimen B at the 1G welding position has the highest corrosion rate value of 0.63856 mm/year and specimen An at the 1G welding position has the lowest corrosion rate of 0.058567 mm/year.

Nephronectin is required to maintain right lung lobar separation during embryonic development.

Nephronectin (NPNT) is a basement membrane (BM) protein and high-affinity ligand of integrin α8β1 that is required for kidney morphogenesis in mice. In the lung, NPNT also localizes to BMs, but its potential role in pulmonary development has not been investigated. Mice with a floxed Npnt allele were used to generate global knockouts (KOs). Staged embryos were obtained by timed matings of heterozygotes and lungs were isolated for analysis. Although primary and secondary lung bud formation was normal in KO embryos, fusion of right lung lobes, primarily the medial and caudal, was first detected at E13.5 and persisted into adulthood. The lung parenchyma of KO mice was indistinguishable from wild-type (WT) and lobe fusion did not alter respiratory mechanics in adult KO mice. Interrogation of an existing single-cell RNA-seq atlas of embryonic and adult mouse lungs identified Npnt transcripts in mesothelial cells at E12.5 and into the early postnatal period, but not in adult lungs. KO embryonic lungs exhibited increased expression of laminin α5 and deposition of collagen IV in the mesothelial BM, accompanied by abnormalities in collagen fibrils in the adjacent stroma. Cranial and accessory lobes extracted from KO embryonic lungs fused ex vivo when cultured in juxtaposition, with the area of fusion showing loss of the mesothelial marker Wilms tumor 1. Because a similar pattern of lobe fusion was previously observed in integrin α8 KO embryos, our results suggest that NPNT signaling through integrin α8, likely in the visceral pleura, maintains right lung lobe separation during embryogenesis.

Is local autogenous morselized bone harvested from decompression through a posterior-transforaminal approach sufficient for single-level interbody fusion in the lower lumbar spine?

BackgroundTo determine the volume and applicability of local autogenous morselized bone (LAMB) harvested and used during posterior-transforaminal lumbar interbody fusion (P-TLIF) in the lower lumbar spine.MethodsClinical and radiographic data of 147 patients (87 males) undergoing P-TLIF from January 2017 to December 2019 for lumbar degenerative diseases were retrospectively analyzed. Computed tomography was used to assess the fusion status (at 6 months, 1 year, and the last follow-up postoperatively), restored disc height, graft fusion area and volume, and the minimum required bone volume (MRBV). Clinical outcomes of P-TLIF were assessed using the Oswestry Disability Index (ODI) and visual analog scale (VAS) for low back pain (LBP) and leg pain (LP).ResultsThe mean follow-up period was 28.4 ± 4.49 months. The patient’s age and diagnosis were correlated to the volume and weight of LAMB (mean volume and weight: 3.50 ± 0.45 mL and 3.88 ± 0.47 g, respectively). The ratio of actual fusion area to the total disc endplate and the ratio of actual fusion volume to the total volume of the disc space were > 40%. MRBV ranged from 1.83 ± 0.48 cm3 to 2.97 ± 0.68 cm3. The proportion of grade 4 or 5 fusions increased from 60.6% at 6 months to 96.6% at the last follow-up. The ODI, VAS-LP, and VAS-LBP scores significantly improved after surgery and remained unchanged during the follow-up.ConclusionWhen combined with a cage, the volume of LAMB harvested from decompression through the unilateral approach at a single-level is sufficient to achieve a solid interbody fusion in the lower lumbar spine with excellent clinical and radiographic outcomes.

A novel electrode to achieve balance between anastomotic strength and tissue thermal damage for radiofrequency-induced intestinal anastomosis

Purpose This paper aimed to develop a novel electrode to achieve balance between anastomotic strength and tissue thermal damage for radiofrequency-induced intestinal anastomosis. Methods The mechanical properties of the novel electrode were analyzed by finite element method, and then the temperature and thermal damage distribution of intestinal tissue during welding process were analyzed by electric-thermal-mechanical multi-field coupled finite element analysis. In ex-vivo experiments, the biomechanical strength of anastomotic area was assessed by indexes of tensile force and burst pressure. A thermocouple probe and an infrared thermal imager were used to monitor the temperature and thermal damage of the intestinal tissue in experiments. Furthermore, histopathological examination and transmission electron microscopy observation were used to observe the morphology and microstructural of anastomotic area. Results A slightly higher mean biomechanical strength is acquired with the tensile force and burst pressure results increasing from 9.7±1.47 N, 84.0±5.99 mmHg to 11.8±2.01 N, 89.6±6.79 mmHg respectively as well as the percentage of necrotic tissue caused by thermal damage decreasing from 89% to 33% for the novel electrode group, with compression force of 20 N, radiofrequency (RF) energy of 120 W and welding duration of 8 s applied to the target regions to achieve anastomosis. Moreover, tightly connected intestinal tissue with collagenic crosslink in the fusion area could be observed by histopathological examination and transmission electron microscopy. Conclusion Our study shows that the proposed novel electrode could achieve balance between anastomotic strength and tissue thermal damage for radiofrequency-induced intestinal anastomosis.

Effect of the ultrasonic phased array on defect detection of HDPE electro-fusion joint

As a common welding method for polyethylene natural gas pipelines, electro-fusion welding has been widely used. However, defects are easy to occur in the fusion area during the welding. In this paper, high-density polyethylene (HDPE) pipes with different types of electric welding joint defects are processed, and the detection effect of the ultrasonic phased array on joint defects is explored. The results show that: Ultrasonic phased array detection technology is easy to operate and reliable. It can detect three common defects: inadequate socket, cold welding, and scratch of oxide scale. In addition, according to the inspection result chart, the defect type can be accurately judged.

Strengthening of Al/Cu dissimilar joint due to complicated interface produced by pulsed TIG welding with a constricted nozzle

Al/Cu dissimilar joining is a key technology for weight reduction in fabricating high-functional products, however, conventional tungsten inert gas (TIG) welding is difficult to be applied due to a large fusion area. The constricted nozzle equipped inside the conventional TIG torch has been developed and can improve the position accuracy of tungsten electrode and arc plasma characteristics, moreover increase the heat input density. In this study, 0.5 mm-thick Al and Cu dissimilar sheets were butt welded using pulsed TIG welding with the constricted nozzle under two welding speed-current combinations of 50 mm/s-85 A and 100 mm/s-105 A. The 50 mm/s-85 A joint exhibited that Al and Cu mixed each other in the entire weld metal, containing two intermetallic compounds (IMC) of Al2Cu and Al4Cu9 mainly in the Al side. In contrast, both elements hardly mixed each other in the 100 mm/s-105 A weld metal and the interface exhibited hook-like shape at a nearly constant pitch, depending on the welding speed and pulse frequency. Consequently, the formation of IMC layers was limited. Based on the three-dimensional images reconstructed using a serial sectioning technique, the hook-shaped Al/Cu interface was also formed inside the weld metal. The mixed-zone volume per unit weld length of the 100 mm/s-105 A joint was estimated to be about 0.12 mm3/mm, and is much smaller than that of the 50 mm/s-85 A joint (0.97 mm3/mm). The average tensile strength of the 100 mm/s-105 A joint were higher than those of the 50 mm/s-85 A joint, suggesting that the hook-shaped Al/Cu interface together with the reduced mixed zone seems to increase the joint strength.

Intelligence Fusion for the European Union’s Common Security and Defence Policy

The data fusion methods, techniques and tools are regarded as a remedy for shortcomings of information/knowledge management and intelligence production. They also address current needs of the holistic, all-source approach to intelligence. Their implementation means the creation of new organizational elements − ‘fusion centers’. The concept of a fusion center has been introduced to and tested in the European Union for years. This paper examines data fusion processes and elements within the EU and focuses on intelligence fusion capabilities developed under the Common Security and Defence Policy (CSDP). The examples of the Single Intelligence Analysis Capacity (SIAC) and EU Hybrid Fusion Cell in the Intelligence and Situation Center (INTCEN) are examined to evaluate challenges, opportunities and limitations of EU intelligence fusion elements. This paper is also an effort to indicate that there are still many elements to be improved within the EU intelligence establishment, including the area of data and information fusion – with the overall aim to effectively and timely support CSDP. Intelligence sharing by Member States with the EU remains one of the main impediments.