Joint Processing Research Articles

Friction in Cylindrical Joints

Cylindrical clearance joints are commonly employed in mechanisms that involve the rotation of a shaft spindle within a cylindrical sliding bearing. The intensity of the friction process in such joints is governed by several factors, including the clearance size between components, the materials of the interacting surfaces, the properties and characteristics of the lubricant, the surface roughness (asperities), and the magnitude of the relative velocity between the joint’s components. To experimentally determine the friction coefficient in cylindrical clearance joints, a custom device was designed and implemented. This device is adaptable to a universal lathe and enables the measurement of the friction coefficient under varying normal forces and relative movement speeds between the joint components. The experimental data were subjected to mathematical analysis, leading to the development of an empirical model. This model effectively characterizes the direction and intensity of the influence of various factors on the friction coefficient, accounting for the use of different lubricants. The findings provide valuable insights into optimizing cylindrical clearance joints for improved performance in practical applications.

Improving multi-talker binaural DOA estimation by combining periodicity and spatial features in convolutional neural networks

Deep neural network-based direction of arrival (DOA) estimation systems often rely on spatial features as input to learn a mapping for estimating the DOA of multiple talkers. Aiming to improve the accuracy of multi-talker DOA estimation for binaural hearing aids with a known number of active talkers, we investigate the usage of periodicity features as a footprint of speech signals in combination with spatial features as input to a convolutional neural network (CNN). In particular, we propose a multi-talker DOA estimation system employing a two-stage CNN architecture that utilizes cross-power spectrum (CPS) phase as spatial features and an auditory-inspired periodicity feature called periodicity degree (PD) as spectral features. The two-stage CNN incorporates a PD feature reduction stage prior to the joint processing of PD and CPS phase features. We investigate different design choices for the CNN architecture, including varying temporal reduction strategies and spectro-temporal filtering approaches. The performance of the proposed system is evaluated in static source scenarios with 2–3 talkers in two reverberant environments under varying signal-to-noise ratios using recorded background noises. To evaluate the benefit of combining PD features with CPS phase features, we consider baseline systems that utilize either only CPS phase features or combine CPS phase and magnitude spectrogram features. Results show that combining PD and CPS phase features in the proposed system consistently improves DOA estimation accuracy across all conditions, outperforming the two baseline systems. Additionally, the PD feature reduction stage in the proposed system improves DOA estimation accuracy while significantly reducing computational complexity compared to a baseline system without this stage, demonstrating its effectiveness for multi-talker DOA estimation.

Sum-Rate Maximization in Massive MIMO with Joint Antenna Selection and Power Allocation

Telecommunications improvements in the last decades have led to an increase in the available data rate and reliability, and to reduce latency. Massive MIMO (mMIMO) has emerged as a promising solution to replace simple antenna setups. This arrangement involves a large number of transmitter antennas compared to the served terminals in the covered area, enabling higher data rates through the key characteristics of mMIMO. Despite its advantages, the utilization of such large arrays is energy-intensive. With fewer antennas, it is possible to achieve high data rates with reduced power consumption. Antenna selection is crucial for energy efficiency while maintaining computational efficiency. Additionally, power allocation in the downlink for each served terminal is an important step to consider. This work aims to propose a joint algorithm for selecting antennas and distributing energy among terminals, simplifying the process through low-complexity algorithms. The results show the penalty in sum-rate capacity for each proposed method. The two proposed algorithms demonstrate an adequate approach to the target value asymptotically as the number of transmitter antennas increases. This implies the possibility of achieving the joint process with significantly lower computational costs compared to perform antenna selection and power allocation separately.

EXPRESS: Investor Learning in Crowdfunded Supply Chain Finance Markets

Crowdfunded Supply Chain Finance (SCF) represents a novel market design that transforms financial flows within the SCF paradigm. It enables crowd investors to serve as financers, lending vital working capital to suppliers facing liquidity problems. A distinctive feature of this market is the mandatory involvement of loan guarantors, which facilitates repeated interactions between investors and fundraisers, potentially fostering investor learning. To understand how such learning dynamics shape investor decision-making, we develop a Bayesian learning model that conceptualizes investor perceptions of guarantor reliability as a subjective attitude underlying the perceived risk of a loan listing. The model posits that investors can learn about a guarantor’s reliability through a series of scheduled repayments involving the same guarantor over time. We consider investor decision-making a joint process comprising two interdependent components: (1) the incidence decision of whether to invest and (2) the amount decision of how much to invest. Our results reveal that investor perceptions of guarantor reliability play a crucial role in shaping both decisions, albeit in distinct ways. While perceived reliability exerts a positive, monotonic effect on amount decisions, its impact on incidence decisions follows an inverted U-shaped pattern. Furthermore, perceived reliability attenuates the positive effect of loan interest rates on both decisions, suggesting that the appeal of higher returns diminishes as investors’ reliability perceptions increase. A posterior analysis further shows that offering high interest rates may become counterproductive when perceived reliability is sufficiently high. These findings provide actionable implications for platform designers and participants in crowdfunded SCF markets.

A novel isolation method for chondrocytes differentiated from synovial fluid-derived mesenchymal stem cell

Mesenchymal stem cells (MSCs) in synovial fluid (SF) actively participate in the regeneration process of healthy joints and have been defined as a good source of chondrocyte cells, which can be obtained by in vitro differentiation of stem cells. This cell population derived from synovial fluid shares cellular characteristics with bone marrow and synovial membrane MSCs with respect to their differentiation potency. Current cell isolation protocols for cartilage therapy mainly focus on the isolation of chondrocytes or MSCs from biological samples. However, the isolation of chondrocytes after the in vitro differentiation from MSCs has not been described in the literature. In this context, we defined a novel method based on Ficoll-Paque density gradient centrifugation for high-throughput isolation of differentiated chondrocytes from human synovial fluid mesenchymal stem cells (hSF-MSCs) without the requirement for cell labeling. In this study, terminally differentiated chondrocytes were obtained after 21 days of chondrogenic differentiation from hSF-MSCs and were isolated using this novel protocol. The isolated chondrocytes were later analyzed for cell viability and functionality by staining with Alcian Blue and by gene expression analysis for chondrocyte markers. In conclusion, the novel chondrocyte isolation method described here is capable of achieving low-cost efficiency. According to the minimal process principles, we hope that this protocol will find use in both translational research and routine clinical applications involving the differentiation and isolation of chondrocytes in vitro.

ERROR ANALYSIS OF THE MULTI-STAGE METHOD OF DETERMINING THE TRAJECTORY PARAMETERS OF LOW-ORBITAL SPACE OBJECTS DURING EXPERIMENTAL TESTING OF INFORMATION AND COMMUNICATION CONTROL SYSTEMS AND SPACE ENVIRONMENT ANALYSIS

The repulsion of large-scale Russian aggression and other existing threats in the sphere of national security and defense of Ukraine require the accelerated development of space information technologies in the state and determine the urgent need to improve the organization of the use of space technologies in the interests of defense, the creation of the necessary organizational structures, the deployment of modern information and communication systems with the aim of increasing space situational awareness. One of the main tasks of space situational awareness is the necessary level of knowledge about outer space, the characteristics of space objects of various origins, previous, current and projected knowledge about the parameters of their orbital motion. This task becomes particularly relevant due to the adversary's use of its space means of special and radio- technical intelligence and means of commercial organization, including microsatellites, as a result of which there is a need to control the routes of the passage of surveillance satellites with the subsequent development of plans for camouflage and other types of countermeasures and protection of troops. The article formulates the task of evaluating the effectiveness of information and communication systems that are being improved as part of conducting experimental tests as part of the System of Control and Analysis of the Space Situation, which are based on algorithms for processing the results of optical observations for maintaining a catalog of space objects. The value of the systematic errors of the initial determination of the motion parameters of a low-orbit circum-circular space object based on the results of optical observations using a multi-stage method based on the approximation of measurements by a circular model and consistent evaluation of planar and in-plane parameters of the orbit was evaluated. Methodological errors introduced when describing the circular motion model of a low-orbit space object along an elliptical trajectory with a small eccentricity are: according to the parameters of the orbit plane, up to 0,80; by period - up to 4 minutes; by the latitude argument – 0,2. In the case when the observation interval does not exceed 1 minute, the maximum errors in angular parameters do not exceed 0,1, which is quite acceptable for solving practical tasks of determining the orbits of small space objects. The systematic error of the period estimation can be compensated by joint processing of the results of optical observations on different turns of the flight.

Study on the Electromigration Organization and Mechanical Properties of Sn2.5Ag0.7Cu0.1RE/Cu Solder Joints

In this study, we designed and manufactured an ideal electromigration testing device for soldering joints to solve the reliability problems caused by temperature and current density changes in the electromigration processes of micro solder joints. We analyzed the effects of temperature and current density on the electromigration β-Sn (single-crystal β-Sn grain) of Sn2.5Ag0.7Cu0.1RE/Cu solder joints, the relationship between the grain orientation and interfacial IMC (intermetallic compound) growth of Sn2.5Ag0.7Cu0.1RE/Cu solder joints, and the mechanical properties of solder joints. The results showed that the angle θ between the c-axis of the β-Sn grain and the current direction for the Sn2.5Ag0.7Cu0.1RE/Cu solder joint gradually decreased to 8.2° when the temperature increased to 150 °C, which accelerated the diffusion of Cu atoms and Cu substrate dissolution. The recrystallization and grain growth of Cu6Sn5 (An intermetallic compound formed by the fusion of copper and tin in a ratio of six to five) grains in the anode region promoted electromigration polarity. Compared with the initial state, the shear strength decreased to 11 MPa, a decrease of 61.3%, the fracture position shifted from the top of the IMC at the cathode interface to the root of the IMC at the cathode interface, and the fracture mode changed from ductile fracture to brittle fracture. With an increase in the current density to 1.1 × 104 A/cm2, θ decreased to 3.2°. In addition, we observed the recrystallization of Cu6Sn5 grains in the anode region and an increase in the grain length and diameter to 6.8–31.9 μm, which further promoted electromigration polarity. Compared with the initial state, the shear strength decreased by 72.5% to 7.8 MPa, and the fracture position shifted from the top of the IMC at the cathode interface to the root of the IMC at the cathode interface. Additionally, the fracture mode changed from ductile to brittle fracture.

Multi-ANN approach for forecasting joint hardness and process variability in the friction stir welding process of AA2024-T3

Multi-ANN approach for forecasting joint hardness and process variability in the friction stir welding process of AA2024-T3

Value co-creation: a metatheory unifying framework and fundamental propositions

PurposeValue co-creation (VCC) represents actors’ joint, communal or shared value-creating processes. However, while existing research has advanced important VCC-based insight, the use of differing metatheoretical lenses to study VCC incurs a risk of theoretical fragmentation, thus potentially hampering this research stream’s continued development. We, therefore, undertake an in-depth review of the corpus of VCC research that focuses on its common conceptual underpinnings as anchored in differing perspectives.Design/methodology/approachTo explore this objective, we undertake an extensive review of extant VCC literature, based on which we develop an integrative conceptual framework of VCC.FindingsWe propose an integrative, metatheory-unifying definition and framework of VCC that reflect its core hallmarks and dynamics across its adopted theoretical perspectives. Based on the framework, we also derive a set of fundamental propositions (FPs) that synthesize VCC’s core tenets.Research limitations/implicationsVCC conceptualizations grounded in differing metatheoretical perspectives reveal the concept’s core interactive, value-creating nature across metatheoretical perspectives. Though VCC emanates from interactivity between any actor constellation, unifying different metatheories of VCC uncovers important insight.Practical implicationsThe study suggests that for effective value co-creation, managers need to establish agreed-upon institutional arrangements, facilitate positive actor relationships and experiences and address challenges like collaboration, transparency, empathy and skill development while ensuring that affective, cognitive, economic and social dimensions of success are met for all actors involved. Successful initiatives require seamless communication, mutual understanding, cost-benefit favorability and public recognition of contributions.Originality/valueGiven VCC’s rising strategic importance, a plethora of studies have investigated this concept from differing metatheoretical perspectives, yielding potential VCC-based fragmentation. Addressing this gap, we take stock of the VCC literature with a view to distilling the concept’s core, trans-metatheoretical hallmarks, as synthesized in the proposed framework and FPs of VCC.

Self-consistent design of the autothermal dual circulating fluidized bed reactor for iG-CLC: A two-step joint process integrating phenomenological method and reduced-order numerical method

Self-consistent design of the autothermal dual circulating fluidized bed reactor for iG-CLC: A two-step joint process integrating phenomenological method and reduced-order numerical method

Analysis of wetting behavior in solder joint process via Ar/H2 atmospheric pressure plasma treatment

Analysis of wetting behavior in solder joint process via Ar/H2 atmospheric pressure plasma treatment

MESHING TRANSFERS IN AUTODESK INVENTOR

In order to improve the execution of drawings of gear elements in the Autodesk Inventor package, an approach to the presentation of geometric information in accordance with the requirements of current standards is proposed, based on the use of developed three-dimensional models of assembly units of gear elements in parametric shells. The basis for the development of the sketch geometry of parametric shells were the basic geometric parameters of the tooth crowns of the elements, since when making drawings of gear meshing elements, the images of the tooth crowns are made in violation of the requirements of current standards. In order to simplify the construction of drawings of gear elements in the Autodesk Inventor package, an algorithm was developed to provide geometric information through the developed three-dimensional models of the parametric shells of the gear crowns of their elements. That is, the geometric information is embedded in the parametric assembly units "gearing in shells". The algorithm is based on working with the parametric shells of the elements of the constituent units, where all the necessary geometric information is represented by a function of the main geometric parameters of real gear crowns. The method of parametric shells considers the issues of touching, implementation, methods of formation of such shells with detailed coverage of their properties and geometric parameters. The rigorous mathematical theory of parametric shells, which involves the joint processing of analytical and geometric information obtained on the basis of the geometry of the gear elements as forming elements, is characterized by generalization in approach and mathematical rigor. At the same time, the presence of toothed crowns of three-dimensional models of gear elements by meshing is ignored. The algorithm for simplified creation of gearing drawings involves making cuts based on sketches, adjusting contour lines and changing the properties of areas in accordance with the requirements of current standards. The library of parametric shells and the algorithm for creating working drawings of both elements and gearing are implemented in the educational process.

Experimental and numerical study on fusion zone in the laser welding process of AA6061-T6 overlap joint: using smoothed particle hydrodynamics (SPH)

Experimental and numerical study on fusion zone in the laser welding process of AA6061-T6 overlap joint: using smoothed particle hydrodynamics (SPH)

Role of TLR7 in the immunopathogenesis of psoriasis and psoriatic arthritis

BACKGROUND: Toll-like receptor 7 (TLR7) plays a significant role in the development of inflammation in psoriasis. However, there are very few data on the role of different polymorphic markers of the TLR7 gene in psoriasis and psoriatic arthritis. AIM: Study of the role of polymorphic marker rs179009 of TLR7 gene in patients with severe psoriasis. MATERIALS AND METHODS: The study was conducted during the period of 2016–2024. The analysis of innate immunity indicators in the study group was performed by obtaining RNA in peripheral venous blood and polymorphisms of the gene recognizing marker rs179009 of the TLR7 receptor were investigated by polymerase chain reaction with TaqMan probes. To assess the area and severity of psoriatic lesions of the skin process, we used a standardised method of assessment — determination of the PASI index. RESULTS: The main group consisted of 168 patients (100%) with psoriasis. Of these, 45 (26.8%) were women and 123 men (73.2%). The average age of the patients was 54.0±14.0 years. The mean duration of psoriasis course was 11.8±0.6 years. The mean psoriasis area and severity index (PASI) value was 17.7±7.2. When analyzing the genotypes of polymorphic marker rs179009 in the TLR7 gene in patients with psoriasis of different severity, it was revealed that heterozygote CT was significantly more frequent in patients with mild psoriasis, and homozygote CC and homozygote TT were registered at PASI 10 (p 0.05). The C allele of the studied marker was significantly more frequent in patients with late psoriasis debut and late development of psoriatic arthritis (p 0.01). In contrast, the T allele was significantly more frequent in patients with early debut of psoriasis and psoriatic arthritis (p 0.01). When analyzing the genotypes of polymorphic marker rs179009 in the TLR7 gene, the occurrence of homozygous CC and TT genotypes was also found to have statistically significant differences. The CC genotype was more frequently registered in patients with late onset of psoriasis and late onset of arthritis (p 0.05). In contrast, the TT genotype was significantly more frequently registered in patients with the debut of skin and joint process before 40 years of age (p 0.05). CONCLUSION: In our study it was found that homozygous carriage of CC and TT genotypes of polymorphic marker rs179009 in the TLR7 gene predisposes to a more severe course of the skin process in psoriasis. Also, the presence in the patient of allele C or homozygote CC of marker rs179009 in the TLR7 gene is a predictor of late onset of the skin process and the development of arthritis. While the presence of the T allele or TT homozygote statistically significantly predisposes to early onset of psoriasis and early onset of joint symptoms with the development of psoriatic arthritis.

Scientific approaches to solving the problem of joint processes of bubble boiling of freon and its movement in a coil

The combined processes of nucleate boiling and refrigerant movement in the tubes of a heat pump are considered. A coil located on the back side of the photovoltaic panel (PV) is used as an additional heating surface. A mathematical model has been created to theoretically determine the temperature on the front surface of a solar cell cooled by freon in a coil from the rear side. A peculiarity of the numerical modeling of nucleate boiling of freon in a coil was the insufficiently detailed study of the process and the lack of references to the results obtained in earlier works. The boundary conditions and assumptions in the numerical modeling of the process of nucleate boiling of freon R407C are clarified, the results are compared with the theoretically found values, which are subsequently used in the design of an energy technology complex consisting of a heat pump and a photovoltaic panel. A mathematical model for theoretical calculation of PV temperature and a methodology for constructing a numerical model of nucleate boiling of freon as part of the methodology for designing energy technology complexes based on renewable energy sources are presented for the first time.

Design of Orthogonal Polyphase Code Set Based on Multipulse Joint Processing

Design of Orthogonal Polyphase Code Set Based on Multipulse Joint Processing

Group velocity dispersion curves estimation based on joint processing of sound pressure and vertical particle velocity.

It is difficult to separate and estimate the intersected group velocity dispersion curves for different normal modes when the frequency is lower than the cutoff frequency of water column. To address this issue, an estimation method based on the joint processing of sound pressure (P) and vertical particle velocity (Vz) is proposed in this paper. Theoretical analysis shows that the amplitudes of P and Vz corresponding to the nth normal mode exhibit a complementary relationship in the certain frequency band, providing a theoretical basis for the method. The feasibility of the method was verified using sea trial data.

The effects of joint process parameters of two-step manufacturing processes on the mechanical performance of biocomposites using Taguchi and multiple regression techniques

This study evaluates the influence of joint parameters of extrusion (extrusion profile temperature) and injection molding (barrel profile temperature and mold temperature) manufacturing processes on the mechanical performance of biocomposite materials via the Taguchi and multiple regression techniques. Statistical analysis of variance (ANOVA) was performed to determine the most influential controllable factors for the individual responses. The results of the study revealed that the mechanical properties of the biocomposites are affected by the joint parameters of the two-step manufacturing techniques. This study will help in the process design of biocomposites with improved mechanical performance.

Computational Methodology for the Development of Wrinkled Tubes by Plastic Deformation

Traditional methods for wrinkled tubes involve welding processes and additional elements, such as plates, screws, rivets, and guides. Considering all the limitations of these processes, this work aims to propose a methodology that allows for maximising the manufacturing process of carbon steel tube joints with seaming using cold forming and minimising the cost of the final product. Therefore, the present work aims to develop a computational model, based on the finite element method, to optimise the deformation process of T6 Aluminium tubes (ø 45 × ø 38.6 mm) with a length of 120 mm. The method uses a steel die with cavities to achieve wrinkled tubes by a forming process. This numerical study was carried out using the Ansys® 2022 R2 software. A nonlinear material and an incremental structural analysis were used. The applied methodology allowed the optimisation of process parameters, the application of forces during tube deformation, the geometry of the die cavity, boundary conditions, and mesh discretisation. Numerical modelling was carried out using the axial symmetry of the assembly (tube–die), enabling a simplified and efficient execution of the final tube geometry. The results were analysed based on the maximum pressure applied to the tube, and the vertical and horizontal displacements of the deformed component, thus obtaining the tube flow with complete filling inside the die cavity at the end of deformation. The die geometry that produced the best results presented a cavity with a radius of curvature of 3 mm, 6 mm in height, and with a depth of 4 mm. The optimised result of the die geometry generated satisfactory results, with the displacement on the x-axis of the tube of approximately 2.85 mm, ensuring the filling of the cavity at the end of the process. For this, the maximum pressure exerted on the tube was approximately 374 MPa.

KARAKTERISTIK BASAL DAERAH TANJUNG AGUNG

Research on crystalline rocks in Lampung has been carried out by various researchers, but this research still does not cover other areas, such as Tanjung Agung village, Katibung District, South Lampung. Therefore, this research aims to analyze the characteristics of basalt rocks in the Tanjung Agung area, South Lampung, which is important for expanding understanding of the geological diversity in the region. These rocks are found in the form of entablature-type columns formed from basalt lava flows. The methods used include literature studies, field observations, and laboratory analysis, especially petrographic analysis, to identify mineral content and rock structure to understand the crystallization process and formation of columnar joints. The results of the petrographic analysis show a porphyritic texture with plagioclase, pyroxene, and hornblende phenocrysts, as well as a finer groundmass. These rocks show gradual crystallization and textural variations such as trachytic, sieve, glomeroporphyritic, and zoning, which reflect processes of decompression, pressure reduction, and magma mixing. Based on the mineral composition, this rock is classified as basalt which undergoes a gradual crystallization process, namely the formation of large crystals (phenocrysts) at depth and the formation of a finer groundmass at the surface. This research also opens up opportunities for geochemical analysis to understand the origin and evolution of magma in the region. Thus, this research provides further insight into the dynamics of magmatism and rock formation in the Tanjung Agung area.