Determination of the Influence of Laser Welding Parameters on the Weld Quality Assurance of Heat-Resistant Alloys

In this study, the method of determining the influence of laser welding parameters on the quality provisions of welded joints made with multicomponent heat-resistant alloys was developed. The regularities of the formation of the welded joint structure of multicomponent heat-resistant alloys obtained by laser welding have been studied. The causes and methodological approaches to eliminate defects in the form of hot cracks were identified. Keywords: laser welding, multicomponent alloys, heat-resistant alloys, welded joints, quality

The development of the Kitasato thumb splint as a conservative therapy treatment for patients with thumb carpometacarpal (CMC) arthropathy

Orthoses are devices that are applied externally to help in the rehabilitation of specific bones or joints. Dr Shuichi Sasaki, Department of Rehabilitation, Kitasato University Hospital, Japan, and his team is working to develop a new orthosis for repatriating thumb arthropathies called the Kitasato thumb splint. It is designed to improve usability of the thumb joint, especially in cases of thumb carpometacarpal (CMC) arthropathy, by taking into consideration the thumb CMC joint structure. It exerts force at the base of the CMC joint to move the thumb into the correct joint alignment, improving symptoms for patients. With the Kitasato thumb splint, Sasaki and the team are also eager to provide patients with an alternative to surgery as they believe that the use of more conservative measures with orthoses can prove effective and also prevent costly surgery. The Kitasato thumb splint is made of a low-temperature thermoplastic knit material and can be assembled in as little as 10 minutes, quickly and conveniently providing patients with additional support during painful daily tasks. In his work, Sasaki and the team are looking at orthoses used to treat thumb CMC osteoarthritis and analysing the pressure on CMC joints using quantitative analysis. So far, the Kitasato thumb splint has been found to help in pain reduction and improvements in the activities of daily living in patients with mild cases (Eaton Classifications I to II) of thumb CMC joints and to also provide some improvement in severe cases (Eaton Classifications III-IV).

A joint structure of multi-distance based metric learning for person re-identification

Person re-identification problem is a valuable computer vision task, which aims at matching pedestrian images of different cameras in a non-overlapping surveillance network. Existing metric learning based methods address this problem by learning a robust distance function. These methods learn a mapping subspace by forcing the distance of the positive pair much smaller than the negative pair by a strict constraint. The metric model is over-fitting to the training dataset. Due to drastic appearance variations, the handcrafted features are weak of representation for person re-identification. To address these problems, we propose a joint distance measure based approach, which learns a Mahalanobis distance and a Euclidean distance with a novel feature jointly. The novel feature is represented with a dictionary representation based method which considers pedestrian images of different camera views with the same dictionary. The joint distance combine the Mahalanobis distance based on metric learning method with the Euclidean distance based on the novel feature to measure the similarity between matching pairs. Extensive experiments are conducted on the publicly available bench marking datasets VIPeR and CUHK01. The identification results show that the proposed method reaches a good performance than the comparison methods.

Stem Cells in Autologous Microfragmented Adipose Tissue: Current Perspectives in Osteoarthritis Disease

Osteoarthritis (OA) is a chronic debilitating disorder causing pain and gradual degeneration of weight-bearing joints with detrimental effects on cartilage volume as well as cartilage damage, generating inflammation in the joint structure. The etiology of OA is multifactorial. Currently, therapies are mainly addressing the physical and occupational aspects of osteoarthritis using pharmacologic pain treatment and/or surgery to manage the symptomatology of the disease with no specific regard to disease progression or prevention. Herein, we highlight alternative therapeutics for OA specifically considering innovative and encouraging translational methods with the use of adipose mesenchymal stem cells.

Study on the Shear Capacity of the Wet Joint of the Prefabricated Bridge Panel with a Special-Shaped Shear Key

Steel-concrete composite beam has been widely applied in civil engineering, and the concrete during operation may crack due to the large shear force at the wet joint. A new concrete panel shear key with the boss is designed to strengthen the shear capacity of the wet joint part. Three different configurations of specimens are tested to study the shear capacity of the wet joint. These specimens include plain concrete specimens with shear keys, specimens with reinforcement and no shear key, and specimens with both shear keys and reinforcements. An experimental study is designed and conducted to verify the shear capacity of each specimen. The experimental results show that the ultimate shear capacity of the new wet joint structure is 73% higher than the conventional one. Meanwhile, the shear capacity of the new wet joint structure is theoretically predicted, and the finite element models are established to demonstrate the effectiveness of the experiment and the good performance of the new wet joint design.

Analysis of Microstructure and Mechanical Properties of AlSi11 after Chip Recycling, Co-Extrusion, and Arc Welding

Recycling of raw materials and is crucial for the production of new products for the global economy. The aim here is, on the one hand, to reduce energy consumption, and, on the other hand, to obtain materials with similar functional properties. The study undertook research on the possibility of processing AlSi11 aluminum chips by compaction and co-extruding to obtain a product in the form of a flat bar with mechanical properties not lower than those of the cast materials. The performed tests and the developed technique allowed to obtain flat bars with more favorable mechanical properties (Yield Strength YS ≥ 155 MPa; Ultimate Tensile Strength UTS ≥ 212 MPa) than the castings (YS ≥ 70 MPa ≥ 150 MPa). The weldability evaluation tests revealed that the material is susceptible to porosity. The presence of pores, which reduces the cross-section (up to 60%), reduces the tensile strength (up to 20 MPa). The typical joint structure and plasticity is obtained, which indicate the possibility of tensile strength improvement.

DPD with PAPR Suppression for F-OFDM Systems

A combined digital pre-distortion (DPD) and peak to average power ratio (PAPR) reduction for Filtered Orthogonal Frequency Division Multiplexing (F-OFDM) systems is proposed where F-OFDM is one of the candidates for 5G waveform technology. In the system, the power amplifier (PA) will produce nonlinear distortion because it works in the saturation region and the high PAPR. DPD based on PAPR reduction structure may be adopted to compensate the nonlinear resulting from PAs. Firstly, in order to reduce the PAPR, a low complexity iterative partial transmission sequence (IPTS) algorithm combined with iterative clipping revision (ICR) is introduced. And then, the joint structure of DPD and IPTS-ICR is proposed. Simulation results show that the proposed structure can improve the PAPR suppression performance of F-OFDM system compared to low complexity IPTS algorithm or ICR algorithm alone. The proposed structure can also effectively improve the nonlinear distortion of the F-OFDM system.