Traditional Joint Research Articles

Electromagnetic and Flow Field Analysis of Multi-DOF Motor With Air Bearing Structure

Due to the traditional multi-DOF motor active joint using the traditional joint ball bearing, it often has friction loss and mechanical contact force and cause low output accuracy. In this paper, an air-floating multi-DOF motor (AMM) supports the rotor with the compressed gas. Firstly, the FEM is adopted to conduct electromagnetic analysis on AMM to obtain the magnetic field distribution of the motor. Then, according to the gas lubrication theory, the flow field is numerically analyzed. The finite element software is also used to simulate the air flow in the air film flow field between the stator and the rotor. Finally, the experimental platform of AMM was established, and the vibration curve of the rotor during the movement was obtained. The experimental results prove the validity of special design requirements of the motor.

Test and Finite Element Analysis of a New Type of Double-Limb Double-Plate Connection Joint in Narrow Base Tower.

The connection between the leg members and diagonal members of the urban transmission line tower is mostly in the form of single-limb connection. This paper puts forward a new connection form of pipe double-limb double-plate connection joint, which is based on the model of key joints in an urban narrow base tower structure. The traditional pipe single-limb single-plate and new pipe double-limb double-plate joint are analyzed and studied from three aspects of theory, numerical simulation and experimental study. Through finite element analysis, it is obtained that the section stress of angle steel under eccentric load is 2.05 times of that under axial load, which is basically consistent with the 2.5 times of the theoretical calculation. This shows that the stress of the angle steel in the pipe double-limb double-plate joint is greatly reduced as the axial stress component, which can ensure the safety of the angle steel. Based on the theoretical analysis of the tensile force of two kinds of joints, through the test research and corresponding numerical simulation of pipe single-limb single-plate and pipe double-limb double-plate joints, under the same load, compared with pipe single-limb single-plate joints, the pipe double-limb double-plate joints designed in this paper can greatly reduce the stress of connection plates and members, and compared with the existing joint forms, the bending stress of joint plates can be reduced by about four times, which greatly improves the bearing capacity of the joint. The research on the pipe double-limb double-plate connection joint will provide the basis for the design of new connection joints of narrow base towers in urban areas.

Home health care industry in India; an account of genderised labour in commercial health care economy

In India traditional care givers has provided care to family members and kith and kin. It is noteworthy that when it comes to family providing care to ailing, elderly and children, care work has been genderised in nature. There has been change in recent decade in Indian economy where many women have involved in jobs outside home leaving a care gap. The other sociological shift is the breaking of traditional joint family system making it difficult for the family members to carry the work of care-giver. This transition in family and economic systems leaving a gap in care giving has enabled markets to enter in creating paid workforce. This paper explores how care work has grown to become commercialized in nature and how it has shifted from feminine unpaid work to paid and genderised nature of work in India.

Conceptualization and cases of study on cyber operations against the sustainability of the tactical edge

The last decade consolidated the cyberspace as fifth domain of military operations, which extends its preliminarily intelligence and information exchange purposes towards enabling complex offensive and defensive operations supported/supportively of parallel kinetic domain actuations. Although there is a plethora of well documented cases on strategic and operational interventions of cyber commands, the cyber tactical military edge is still a challenge, where cyber fires barely integrate to the traditional joint targeting cycle due to, among others, long planning/development times, asymmetric effects, strict target reachability requirements, or the fast propagation of collateral damage; the latter rapidly deriving on hybrid impacts (political, economic, social, etc.) and evidencing significant socio-technical gaps. In this context, it is expected that Tactical Clouds disruptively facilitate cyber operations at the edge while exposing the rest of the digital assets of the operation to them. On these grounds, the main purpose of the conducted research is to review and in depth analyze the risks and opportunities of jeopardizing the sustainability of the military Tactical Clouds at their cyber edge. Along with a 1) comprehensively formulation of the researched problematic, the study 2) formalizes the Tactical Denial of Sustainability (TDoS) concept; 3) introduces the phasing, potential attack surfaces, terrains and impact of TDoS attacks; 4) emphasizes the related human and socio-technical aspects; 5) analyzes the threats/opportunities inherent to their impact on the cloud energy efficiency; 6) reviews their implications at the military cyber thinking for tactical operations; 7) illustrates five extensive CONOPS that facilitate the understanding of the TDoS concept; and given the high novelty of the discussed topics, this paper 8) paves the way for further research and development actions.

Design and analysis of a tendon-driven snake-arm robot based on a spherical magnets

A tendon-driven snake-arm robot can achieve a bending motion with multiple degrees of freedom (DOF) with a compact structure, which enables the robot to be widely used in confined environments. However, if a conventional tendon-driven snake-arm robot is subject to a lateral force on the distal end, it will experience passive compliance. In this paper, a 2-DOF rolling joint is proposed, based on the opposite-pole attraction of spherical magnets, which has a relatively simple structure compared with traditional joints. By serially connecting the 2-DOF rolling joints, a novel snake-arm robot is designed utilizing a tendon-driven approach. The kinematic model and workspace of the snake-arm robot are obtained, and the bending motion is validated. Based on the kinematic model, it is theoretically proven that the proposed robot can avoid passive compliance. In addition, this feature is verified through load experiments on the developed prototype.

Abstract 817: Probing the diabetes - colorectal cancer link using gene - environment interaction analyses

Abstract Background: Type 2 diabetes mellitus (T2D) is an established risk factor for colorectal cancer. However, the mechanisms underlying this relationship are unclear and it is not known if the association is modified by genetic variants. To provide insights into the molecular pathways potentially linking diabetes and colorectal cancer, we undertook a large-scale gene-environment interaction analysis (GxE). Methods: We tested multiplicative statistical interactions between approximately 7 million common (allele frequency >1%) genetic variants and T2D status in 31,529 colorectal cancer cases and 42,861 controls of European ancestry from 3 genetic consortia (GECCO/CCFR/CORECT). Statistical methods included traditional case-control logistic regression, case-only analyses, joint tests (2df/3df), and two-step approaches. We also explored additive and multiplicative interactions between polygenic risk score (PRS) of the known genome-wide significant loci for colorectal cancer and T2D. Results: Overall, T2D was positively associated with colorectal cancer risk [odds ratio [OR]: 1.25 (95% confidence interval [CI]: 1.14-1.36)]. A statistically significant interaction was identified between T2D status and an intronic variant in LRCH1 (rs9526201) and colorectal cancer risk using the 2-d.f. joint test (p-value:1.44x10-8). A statistically significant additive scale interaction between PRS for colorectal cancer and T2D was found (p-value: 1.8x10-10) such that the observed risk of developing colorectal cancer for individuals with T2D and a 1 standard deviation (SD) higher increment of PRS compared to non-diabetics with the lowest PRS was 0.184 more than if there was no interaction between T2D and PRS. Conclusion: These results suggest that variation in a gene related to immune function may modify the association of T2D with colorectal cancer and potentially provide novel insights into the biology underlying this relationship. Furthermore, our data show that genetic risk prediction models for CRC may need to consider non-genetic risk factors. Citation Format: Niki Dimou, Andre E. Kim, Orlagh Flanagan, Neil Murphy, Emmanouil Bouras, Peter T. Campbell, Graham Casey, Steven Gallinger, Stephen B. Gruber, Li Hsu, Mark A. Jenkins, Yi Lin, Victor Moreno, Conghui Qu, Edward Ruiz-Narvaez, Mariana C. Stern, Yu Tian, Kostas Tsilidis, W. James Gauderman, Marc J. Gunter, Ulrike Peters. Probing the diabetes - colorectal cancer link using gene - environment interaction analyses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 817.

Experimental Study on Mechanical Performance of U-Shaped Steel-Encased Concrete Composite Beam-Girder Joints

This paper proposes a novel U-shaped steel-encased concrete composite beam-girder joint (referred to herein as the novel composite beam-girder joint), in which the U-shaped beams at two sides (L and R) are inserted into a shaped sleeve, and the U-shaped girder and two U-shaped beams are connected by the shaped sleeve through welding. Compared with the traditional beam-girder joints, the novel composite beam-girder joints take advantage of easy construction, light weight, and short construction period. The failure patterns, load-strain and load-deflection curves, and strain distributions of the novel composite beam-girder joints were investigated through the static loading tests on two full-scale specimens, denoted as GBJ1 and GBJ2. The two specimens were varied in beam section reinforcements. Specimen GBJ2 was equipped with 3Ф16 additional bars in the U-shaped beams based on Specimen GBJ1. Test results show that the two specimens failed as the through arc cracks developed at the concrete slab interfaces. The additional bars can increase the bearing capacity slightly but will also increase the stress concentration on the bottom flange of the shaped sleeve, leading to the decrease of ductility for Specimen GBJ2. The slab effect is considered in the test and can thus reflect the actual stress state of the beam-girder joints well. This study can provide a reference for the design and application of beam-girder joints.

Building technique of the Theater at ancient Messene

AbstractThis paper reports and examines the building techniques of the recently excavated Messene Theater in Greece. In the Hellenistic period, both traditional building materials (poros and limestone) and methods (masonry, jointing, and transportation) were employed in the Messene Theater. The massive retaining wall of the auditorium and the skenotheke were built using limestone, but local poros stone was favored for use in the retaining wall of the parodos and other parts of the building. Traces of traditional joint and lifting techniques (dowels, clamps, lifting ropes, and lewis) have been observed. In the Roman imperial period, both Roman building materials (marble, granite, and brick) and local traditional masonry have been observed. The white and multi‐colored marble applied to the scaenae frons was most likely delivered from quarries from both local and other provinces. Remarkably, the mason marks on the stone blocks of the Roman imperial period suggest a systematic modification by previous building materials. Similarly, the vaulting of the Roman scene building seems to have been built using cut‐stone voussoirs instead of fired‐brick. The observed building techniques of the Messene Theater suggest a conservative tendency in provincial Roman Greece.

Effect of Emulsion Powder Content in VAE Emulsion on Tensile Properties of Joint Filler

The traditional joint filler used in our country is easy to be damaged by the environment. At present, polymer composite is used to form a new type of polymer joint filler (NPJF) to improve the properties of joint filler. In this paper, by comparing and testing the various indexes of the joint filler under tensile load under the condition of 5 kinds of latex powder content, the performance of the joint filler after molding was studied. The results show that the tensile strength and tensile modulus of the joint filler increase with the increase of latex powder content, the elongation at break and peak strain decrease first and then increase. The influence of the amount of latex powder on the tensile properties of the joint filler mainly lies in the improvement of the aggregate ash ratio, the formation of the film structure and the change of the overall microstructure.

Reconfigurable helical lattices via topological morphing

Composite materials can enhance morphing and deployable structure capability due to their high degree of tailorability and their favourable stiffness- and strength-to-weight ratios. One such structure, the bistable helical lattice, is augmented in current work. To date this type of structure, shows promise in aerospace systems which require linear actuation. Herein, morphing capabilities are enhanced by removing traditional mechanical fasteners at the joints, and replacing them with magnets which allow detachment and re-attachment in a controlled, purposeful way. Within a helical lattice structure, joint detachment creates new functionality by allowing a new topology to be formed which is used to convert a linear actuator to one that is curved and then back again, when the joints are reattached. The required force to actuate the topological change is characterised through the use of both finite element analysis and experimental testing. The structural response is observed through the manufacture and testing of a demonstrator which replaces the traditional joints with a series of magnets in order to capture this variable topology behaviour.

Modified IWO algorithm for topological optimum synthesis of the displacement amplifying compliant mechanism

The conventional mechanisms transmitted force and displacement through rigid members (high stiffness) and traditional joints (with high softness), where recently, researchers have come up with new systems called compliant mechanisms that transfer power and mobility through the deformation of their flexible members. One of the most frequently used approaches for designing compliant mechanisms is topology optimization. Extracting the optimal design of a displacement amplifying compliant mechanism using the modified Invasive Weed Optimization (MIWO) method is the current study's main novelty. The studied mechanism is a compliant micro-mechanism that can be used as a micrometric displacement amplifier. The goal of this synthesis is to maximize the output-to-input displacement ratio. In this research, a new random step is added to the Invasive Weed Optimization (IWO) method; the new seeds can be spread farther from their parents, which can be improved the algorithm's abilities. The results show that the use of the modified IWO algorithm for this problem has led to a significant improvement over the results from similar articles.

Design of adhesively bonded lap joints with laminated CFRP adherends: Review, challenges and new opportunities for aerospace structures

Adhesive bonding is one of the most suitable joining technologies in terms of weight and mechanical performance for current carbon fiber reinforced polymer aircraft fuselage structures. However, traditional joint topologies such as single overlap joints induce high peel stresses, resulting in sudden failure and low joint strength when compared to metal adherends. This drawback in using carbon fiber reinforced polymer is hindering their performance and efficiency in full-scale structures where joints are essential.The goal of this paper is to review how the joint design can help to improve the lap shear strength of composite bonded joints, to recognize the challenges that still need to be understood and to give insight into new opportunities. The focus is thereby on means to increase the matrix-dominated out-of-plane strength of the adherend in order to postpone delamination failure, as it is known to be the most prone type of failure of composite bonded joints. The paper is divided in two main parts: firstly, a review of topology-related and material-related design parameters is given and secondly, future opportunities to improve out-of-plane strength of CFRP bonded joints yet to be explored are discussed.

Strength Calculation and Equal Load-Carrying-Capacity Design of an Undermatched HSLA Lap Joint under Out-of-Plane Bending

This work aimed to design an undermatched lap joint that has an equal load-carrying capacity (ELCC) with a traditional equalmatched joint under out-of-plane bending. A weld strength calculation method was proposed based on the similarity of a lap joint and a T joint, as shown using linear elastic finite element (FE) analysis, and then applied in the analysis of a lap joint and the design of an ELCC lap joint. A single lap joint of HQ785 steel was chosen for experimental verification. The bending force limit of the ELCC joint was 93.35% of the theoretical prediction and 96.90% of the traditional equalmatched joint. The results show that the weld strength calculation method and the ELCC design method are reasonable and feasible.

STORY VERTICAL POST-COMPRESSION FOR TIMBER BUILDINGS: A NEW SYSTEM FOR SEISMIC IMPROVEMENT OF CLT WALLS

A new constructive system for multi-story timber building with CLT panels is described. A vertical post-compression of each story allows avoiding the use of traditional joints, as hold-downs and angle brackets. Reducing the number of joint elements, the new constructive system may be faster than the traditional one. The story vertical post-compression allows to improve a shear-type behavior of each story with better performances of the CLT panels. Numerical studies on a single panel and a fivestory building are made performing pushover static equivalent nonlinear analyses. These studies show as the new system allows better performances, in the case of horizontal actions, in comparison to the traditional constructive use of CLT panels. Thus, the new system is very suitable, for timber buildings, in areas prone to seismic actions and wind actions.

Block sparse representation approach to 2D DOA and polarisation estimation of wideband signals using a sparse vector antenna array

In this study, a multi-polarised two-dimensional (2D) planar array of sparsely located vector antennas (VAs) is designed for the block sparse representation (SR)-based 2D direction finding and polarisation parameter estimation of wideband signals. In order to alleviate the inter-VA mutual coupling effect, the minimum inter-VA spacing of the 2D sparse array is constrained to be no less than one wavelength that corresponds to the highest signal frequency. To reduce the computational complexity of parameter estimation, the 2D block SR model for the 2D difference coarray output at a certain frequency bin is established, under which the two direction cosine terms for 2D direction-of-arrival (DOA) estimation are decoupled with the polarimetric terms. This enables separated but simultaneous 2D direction finding and polarisation parameter estimation with the newly developed joint 2D block orthogonal matching pursuit (Joint-2D-BOMP) subband fused sparse recovery algorithm. Moreover, with the use of two spatial only (polarisation independent) over-complete dictionaries, the representation dimension of the new 2D block SR model is greatly reduced as compared with the traditional space-polarisation joint SR model. The efficacy of the presented VA array geometry and the associated parameter estimation method is validated by computer simulations.

Комплексная оценка качества клеемеханических соединений

The component tree of the complex index of the glued-mechanical joint quality is presented. Its main branches are purpose and processability indices, and economy indices. The change of quality indices when replacing the traditional mechanical joints (welded, riveted) by the glued-mechanical ones (glued-welded, glued-riveted) was examined. The classification of factors that have influence on fracture processes of glued-mechanical joints is given. Based on analysis of fracture characters of glued-mechanical joints, possible causes of fractures are demonstrated.

A Joint Detection and Decoding Scheme for PC-SCMA System Based on Pruning Iteration

Polar coding and sparse code multiple access (SCMA) are key technologies for 5G mobile communication, the joint design of them has a great significance to improve the overall performance of the transmitter-receiver symmetric wireless communication system. In this paper, we firstly propose a pruning iterative joint detection and decoding algorithm (PI-JDD) based on the confidence stability of resource nodes. Branches to be updated are dynamically pruned to avoid redundant iterative, which is able to reduce 24~50% complexity while achieving the approximate error performance of traditional serial joint iterative detection and decoding algorithm S-JIDD. Then, to further reduce the bit error rate (BER) of the receiver, a cyclic redundancy check (CRC) termination mechanism is added at the end of each joint iteration to avoid the convergence error caused by decoding deviation. Simulation results show that the addition of an early stopping criterion can achieve a remarkable performance gain compared with the S-JIDD algorithm. More importantly, the combined algorithm of the two proposed schemes can reduce the computational complexity while achieving better error performance.

Equal Load-Carrying Design of Lapped Joints of Al–Cu Dissimilar Materials

In order to avoid the adverse effects of additional moment and stress concentration of traditional lap joints, a new lap joint was put forward, according to the concept of “equal load-carrying”. Through static analysis and brazing characteristics consideration, the equal load-carrying design method of Al–Cu lap joint based on brazing method was established. Through three types of brazing, the relationship among two fracture modes, brazing process and static tension curve of lap joint, was analyzed. The results demonstrated that the selection of solder was required to simultaneously meet the requirements of brazability and mechanical properties. A certain relationship existed between the fracture mode of the lap joint and the static tensile curve, while the segments of the static tensile curve corresponded to the fracture paths of the two fracture modes. When the brazing holding time was quite short, the interface bonding was poor, while the bearing capacity of the joint was low; when the holding time was suitable, the bearing capacity of the joint reached the corresponding highest, while the fracture mode conformed to the equal load-carrying design; when the brazing holding time was quite long, the bearing capacity of the joint remained at a high level, but the fracture mode was the same as the holding time was quite short.

Finite Element Study on the Shear Capacity of Traditional Joints between Walls Made of AAC Masonry Units.

This paper presents the development of a numerical model aimed at the simulation of nonlinear behaviour of traditional joints between walls made of autoclaved aerated concrete (AAC) masonry units. Nonlinear behaviour and cracking of AAC and mortar were simulated using the concrete damaged plasticity (CDP) model available in the ABAQUS finite element software. The paper also presents and discusses the results of an experimental campaign involving testing six T-shaped, monosymmetric samples with traditional joints between walls loaded in shear. The results were used to validate the numerical model. The validation confirmed that the model is capable of producing accurate results and predicting the structural behaviour with a reasonably good accuracy in elastic and post-elastic stages. Furthermore, a sensitivity study was conducted, in which the variation of elastic modulus, Poisson’s ratio, tensile strength, compression strength and fracture energy of AAC was investigated. Results showed that the variation of elastic modulus, tensile strength and fracture energy is most critical to the structural behaviour of the model, while variation of the remaining parameters has a negligible effect on the results.

The Efficacy of Dynamic Stabilization of the First Carpometacarpal Joint: A Prospective Randomized Controlled Trial

Abstract Date Presented 03/26/20 In adults with first carpometacarpal degenerative joint disease, does a dynamic stabilization home exercise program (HEP) decrease pain and increase function more than a traditional HEP? Research is needed to assess if this approach will lead to greater function and less pain than the currently accepted approach. It is important for OTs to have a holistic approach that includes traditional joint protection, orthosis use, and self-management of HEPs. Primary Author and Speaker: Cindy Ivy Additional Authors and Speakers: Kaylee Martino, Sara Murphy, Celine De Jesus, Stephanie Kannas, Kimberly McVeigh, Allison Nickolaou