Joint Samples Research Articles

Oscillatory pressure-assisted plastic joining of zirconia ceramics with excellent flexural strength

Here, an oscillatory pressure is applied for the plastic joining of zirconia ceramics. The shear strain of all joined sample is as high as 0.82. After plastic joining, no large pores are observed in the joint layer, and the joint samples remain dense. The grain size of all joined samples is nearly 50 % higher than that of the sample OS (joint free). The fracture mode of the sample changes from the intergranular fracture of the sample OS to the transgranular fracture of the joined samples. The maximum flexural strength of the joined sample is as high as 1552±225 MPa, which is 110 % higher than that of the parent material. Such an increase in flexural strength may be due to the removal of large pores under a high shear strain, grain boundary strengthening, and the introduction of high-density dislocations.

Plant diversity effects on soil multistability

Soil is the basis for life on Earth as we know it. Healthy and stable soil is a prerequisite for well-functioning terrestrial ecosystems and has, thus, been proposed to play a key role in plant diversity–ecosystem functioning relationships. The overall objective of this sub-project is to study multidimensional soil stability as affected by plant diversity in a long-term plant diversity experiment. We designed three coordinated work packages (WPs) to comprehensively assess soil multistability to environmental fluctuations and climate extremes by considering the biological, chemical and physical dimensions that are key for soil functioning. We will use all unique facilities and approaches of the Jena Experiment Research Unit by combining synthesis of long-term data in the Main Experiment and the ΔBEF Experiment with performing new soil analyses in the DrY Experiment, the ResCUE Experiment and a joint CoMic Experiment, to gain a better mechanistic understanding of plant diversity–ecosystem functioning relationships. In close collaboration with other sub-projects, we will assess biological, chemical and physical soil properties and stability indicators that will be used to calculate soil multifunctionality and multistability indices. In WP1, we will build on three unique datasets to explore short-term and long-term effects of plant diversity on the stability of soil (microbial) properties. In WP2, we will combine different datasets and approaches to explore if plant diversity effects on the magnitude and stability of soil properties increase with abiotic and biotic stresses. In WP3, we will combine measurements of the above-mentioned dimensions of soil stability to explore if plant diversity increases the stability of multiple soil properties under hot drought. This sub-project is at the heart of the Research Unit by testing the overarching hypotheses outlined in the Coordination Proposal of the Jena Experiment, contributing to all main experiments, sharing data and performing joint sampling campaigns with all sub-projects and, at the same time, introducing a novel concept of soil multistability as affected by plant diversity and climate extremes. We propose to use a combination of simple, high-throughput (e.g. bait-lamina test) and more sophisticated methods (e.g. extracellular polymeric substances analyses) to be able to investigate temporal dynamics of soil processes and their mechanistic basis. Taken together, the results of the three WPs will provide new insights into the stabilising mechanisms of soil properties in the long term and in relation to climate extremes through plant diversity.

The Calibrated Bayesian Hypothesis Test for Directional Hypotheses of the Odds Ratio in $$2\times 2$$ Contingency Tables

AbstractThe $$\chi ^{2}$$ χ 2 test is among the most widely used statistical hypothesis tests in medical research. Often, the statistical analysis deals with the test of row-column independence in a $$2\times 2$$ 2 × 2 contingency table, and the statistical parameter of interest is the odds ratio. A novel Bayesian analogue to the frequentist $$\chi ^{2}$$ χ 2 test is introduced. The test is based on a Dirichlet-multinomial model under a joint sampling scheme and works with balanced and unbalanced randomization. The test focusses on the quantity of interest in a variety of medical research, the odds ratio in a $$2\times 2$$ 2 × 2 contingency table. A computational implementation of the test is developed and R code is provided to apply the test. To meet the demands of regulatory agencies, a calibration of the Bayesian test is introduced which allows to calibrate the false-positive rate and power. The latter provides a Bayes-frequentist compromise which ensures control over the long-term error rates of the test. Illustrative examples using clinical trial data and simulations show how to use the test in practice. In contrast to existing Bayesian tests for $$2\times 2$$ 2 × 2 tables, calibration of the acceptance threshold for the hypothesis of interest allows to achieve a bound on the false-positive rate and minimum power for a prespecified odds ratio of interest. The novel Bayesian test provides an attractive choice for Bayesian biostatisticians who face the demands of regulatory agencies which usually require formal control over false-positive errors and power under the alternative. As such, it constitutes an easy-to-apply addition to the arsenal of already existing Bayesian tests.

Comparative Study of the Impurity Effect on SnAgCu and SnZn Solder Joints with Electrodeposited Cu.

Sn-3Ag-0.5Cu (SAC305)- and Sn-9Zn-based alloys (Sn-Zn-X, X = Al, In) are lead-free solders used in the fabrication of solder joints with Cu metallization. Electroplating is a facile technology used to fabricate Cu metallization. However, the addition of functional additive molecules in the plating solution may result in impurity residues in the Cu electroplated layer, causing damage to the solder joints. This study investigates the impurity effect on solder joints constructed by joining various solder alloys to the Cu electroplated layers. Functional additives are formulated to fabricate high-impurity and low-impurity Cu electroplated samples. The as-joined solder joint samples are thermally aged at 120 °C and 170 °C to explore the interfacial reactions between solder alloys and Cu. The results show that the impurity effect on the interfacial reactions between SAC305 and Cu is significant. Voids are massively formed at the SAC305/Cu interface incorporated with a high impurity content, and the Cu6Sn5 intermetallic compound (IMC) grows at a faster rate. In contrast, the growth of the Cu5Zn8 IMC formed in the SnZn-based solder joints is not significantly influenced by the impurity content in the Cu electroplated layers. Voids are not observed in the SnZn-based solder joints regardless of the impurity content, indicative of an insignificant impurity effect. The discrepancy of the impurity effect is rationalized by the differences in the IMC formation and associated atomic interdiffusion in the SAC305- and SnZn-based solder joints.

Fretting fatigue damage mechanism of Ti6Al4V dovetail joint specimens at high temperature treated with salt layer

Salt layer preparation on the contact surface of Ti6Al4V dovetail joint specimens using solid NaCl and Na2SO4 deposition, the effect of hot salt layer on fretting fatigue properties of Ti6Al4V alloy at high temperature was studied. The maximum stress load and temperature are 10 kN and 500 °C, respectively. The results show that the average fatigue life of the base metal dovetail joint sample (BM sample) is 9.93×104, and the average fatigue life of the hot salt dovetail joint sample (HS sample) is increased to 69.9×104. The increase in fatigue life stems from the fact that the hot salt layer promotes the generation of thicker loose oxides on the surface of the Ti6Al4V alloy, besides, the lubricating effect of the oxide with higher hardness and the wear debris alleviates the fretting damage between the dovetail joint sample and the contact surface of the fretting pad. Fracture analysis shows that the hot salt layer does not change the crack initiation mechanism, and all of them show single crack source propagation and ductile fracture mechanism. Analysis of crack formation zone by electron back-scattered diffraction (EBSD), it is found that the presence of less dislocation distribution in the HS sample relative to the BM sample. The dislocations are more concentrated on the crack propagation paths and the fretting fatigue contact surfaces. This indicates that the BM sample produced more significant plastic deformation in the crack formation zone, accelerating crack initiation. The contact surface plastic deformation of the HS sample is small and the fretting fatigue life is enhanced.

Investigation of The Efficacy of Sericin in Experimental Knee Osteoarthritis Model in Rats through the TGF-Beta/Smad Pathway

OBJECTIVE: This study investigates the therapeutic efficacy of sericin in rats with knee osteoarthritis (KOA) induced with monosodium iodoacetate (MIA), focusing on evaluating its effectiveness through the TGF-β/Smad pathway. MATERIALS AND METHODS: The KOA model was established by injecting MIA into the knee joint and the rats were randomly divided into three groups:group 1 (control), group 2 (KOA control), and group 3 (KOA+sericin). Sericin was administered intratendinously to rats on days 1,7,14, and 21 (50 µL,0.8 g/kg/mL). After 21 days, the rats were sacrificed, and serum samples were analyzed using the ELISA method to measure TGF-β1, Smad2, and CTGF levels. Additionally, knee joint samples underwent histopathological evaluations with hematoxylin-eosin staining and immunohistochemical assessment using TGF-β1 and Smad2/3 antibodies. RESULTS: Serum TGF-β1 and CTGF levels were significantly increased in group 2 vs. group 1 (P

AleRax: a tool for gene and species tree co-estimation and reconciliation under a probabilistic model of gene duplication, transfer, and loss.

Genomes are a rich source of information on the pattern and process of evolution across biological scales. How best to make use of that information is an active area of research in phylogenetics. Ideally, phylogenetic methods should not only model substitutions along gene trees, which explain differences between homologous gene sequences, but also the processes that generate the gene trees themselves along a shared species tree. To conduct accurate inferences, one needs to account for uncertainty at both levels, that is, in gene trees estimated from inherently short sequences and in their diverse evolutionary histories along a shared species tree. We present AleRax, a software that can infer reconciled gene trees together with a shared species tree using a simple, yet powerful, probabilistic model of gene duplication, transfer, and loss. A key feature of AleRax is its ability to account for uncertainty in the gene tree and its reconciliation by using an efficient approximation to calculate the joint phylogenetic-reconciliation likelihood and sample reconciled gene trees accordingly. Simulations and analyses of empirical data show that AleRax is one order of magnitude faster than competing gene tree inference tools while attaining the same accuracy. It is consistently more robust than species tree inference methods such as SpeciesRax and ASTRAL-Pro 2 under gene tree uncertainty. Finally, AleRax can process multiple gene families in parallel thereby allowing users to compare competing phylogenetic hypotheses and estimate model parameters, such as duplication, transfer, and loss probabilities for genome-scale datasets with hundreds of taxa. GNU GPL at https://github.com/BenoitMorel/AleRax and data are made available at https://cme.h-its.org/exelixis/material/alerax_data.tar.gz.

Enhancing shear strength in 3D printed single lap composite joints: A multi‐faceted exploration of GNP integration, print orientation, utilizing artificial neural networks, and dynamic analysis

AbstractThe state‐of‐the‐art manufacturing process known as additive manufacturing (AM) employs components that may be processed by AM, including ceramics, polymeric materials, metallic substances, titanium, metallic substances, and composites, to produce parts with intricate designs and exact properties. Fused deposition modeling (FDM) is a rapidly growing 3D printing technique. However, most FDM systems only support polylactic acid (PLA) or acrylonitrile butadiene styrene (ABS) as a printing medium. The impact of print orientations and graphene nanoparticles upon the tensile and shear properties of PLA single‐lap joint samples created by FDM has been investigated in this work. According to experimentation, the 0° orientation has the highest load‐bearing capacity and shear strength compared to 45° and 90°. Also, addition of GNP to epoxy adhesive improved greatly, with 0.25 to 1.00 weight percentages of 20.94, 12.34, 38.98, and 31.11%, respectively. FESEM has been used to analyze the failure criteria. The free vibrational analysis confirmed that the 3DS6 sample had the highest natural frequency (598.7 Hz) compared to all other samples. The artificial neural network (ANN) approach accurately predicted the failure load. The overall =0.8471 achieved is below the permissible margin of error, indicating that both the outcomes are reliable and in satisfactory agreement.

Dynamic mechanical behavior of sandstone with filled joints at varying angles under coupled triaxial static and dynamic loading

Natural or artificially formed rock composite structures with consecutively filled joints at varying angles are frequently disturbed by coupled static and dynamic loads. Understanding the impacts of the confining pressure and joint angle on the dynamic mechanical behavior of rocks is important for the stability of rock mass engineering structures. In this study, seven joint angles and four confining pressures were considered. Dynamic triaxial compressive tests of sandstone with consecutively filled joints were conducted using a split Hopkinson bar (SHPB) apparatus. The test results showed that varying degrees of “strain rebound” phenomena were observed in the stress–strain curves, implying that the jointed samples in the failure stage could still store more elastic energy, which may trigger rock burst accidents in practical engineering. Moreover, the dynamic compressive strength and elastic deformation modulus were proportional to the confining pressure, but showed a trend of slight decrease followed by a noticeable increase with an increase in the joint angle from 0° to 90°. The combined effects of axial pre-stress and confining pressure resulted in different trends in the dynamic peak strain. The plastic deformation moduli of samples with smaller joint angles were insensitive to changes in the confining pressure and smaller joint angles, whereas those of samples with larger joint angles were sensitive to changes in the confining pressure and larger joint angles. In addition, the experimental tendency of the dynamic compressive strength under coupled triaxial static and dynamic loading was in good agreement with the theoretical derivation.

Numerical investigation of solder joint shape for micro-spring package during vacuum vapor phase soldering

The novel micro-coil spring package has become a new choice for reliable applications in extreme temperature change, high-strength impact, long-term vibration and other harsh environments due to the advantages arising from its special packaging design. The study of solder joint shape is an important step in the characterization of the package reliability. By Ansys Fluent software, the finite volume method was applied to investigate the flow behavior of molten solder during vacuum vapor phase soldering and the volume of fluid model was used to track the solder melt front. The simulation results reveal the effect of two critical process parameters (solder volume and pad diameter) on solder joint shape in micro-spring array package. The fillet height of the solder joint increases with decreasing pad diameter and decreases with decreasing solder volume. The optimal solder volume is 0.07 mm3 coupled a pad diameter of 0.80 mm, producing suitable fillet height and nice concave fillet shape, which is in agreement with the real sample of micro-spring soldering joint. The good consistency between experiment and simulation proves that the finite element method can effectively predict the shape of the melted solder. This work paves the way for the optimization of the solder joint shape in the electronic assembly.

Microsporidia (Encephalitozoon cuniculi) in Patients with Degenerative Hip and Knee Disease, Czech Republic.

Total joint arthroplasty is a commonly used surgical procedure in orthopedics. Revision surgeries are required in >10% of patients mainly because of prosthetic joint infection caused by bacteria or aseptic implant loosening caused by chronic inflammation. Encephalitozoon cuniculi is a microsporidium, an obligate intracellular parasite, capable of exploiting migrating proinflammatory immune cells for dissemination within the host. We used molecular detection methods to evaluate the incidence of E. cuniculi among patients who had total hip or knee arthroplasty revision. Out of 49 patients, E. cuniculi genotypes I, II, or III were confirmed in joint samples from 3 men and 2 women who had implant loosening. Understanding the risks associated with the presence of microsporidia in periprosthetic joint infections is essential for proper management of arthroplasty. Furthermore, E. cuniculi should be considered a potential contributing cause of joint inflammation and arthrosis.

New 2D roughness parameters with geometric and physical meanings for rock joints and their correlation with joint roughness coefficient

Determining the joint roughness accurately will better serve the peak shear strength estimation models of rock joints used for stability assessment of rock masses. Considering the defects of the existing quantitative characterization parameters for two-dimensional (2D) joint roughness, especially the lack of explicit geometric and physical meaning, we proposed two new 2D roughness parameters, θ2D and h2D. The former, θ2D, represents the average inclination angle of all potential contact asperities over the entire joint profile, while the latter, h2D, characterizes their average undulation height. Both parameters are closely related to the shear strength of rock joints. Then, the roughness parameters θ2D and h2D of 102 rock joint profiles digitized at 0.5 mm sampling interval were calculated, and a new nonlinear regression equation for the determination of the 2D joint roughness coefficient (JRC) was established by combining the calculated results of the two roughness parameters. It was verified that the proposed equation could give accurate JRC estimation values of the 10 standard profiles of rock joints. Through the comparative analysis of the experimental data collected from earlier studies for the peak shear strength of 73 rock joint samples and corresponding estimated values, the equation was further verified to be applicable and accurate for estimating the JRC values of rock joints. Furthermore, we discussed the effects of shear direction and sampling interval on roughness and further provided another equation that could be applied to estimate the JRC values of joint profiles at the sampling interval of 1.0 mm.

Enhanced performance of EEG-based brain-computer interfaces by joint sample and feature importance assessment.

Electroencephalograph (EEG) has been a reliable data source for building brain-computer interface (BCI) systems; however, it is not reasonable to use the feature vector extracted from multiple EEG channels and frequency bands to perform recognition directly due to the two deficiencies. One is that EEG data is weak and non-stationary, which easily causes different EEG samples to have different quality. The other is that different feature dimensions corresponding to different brain regions and frequency bands have different correlations to a certain mental task, which is not sufficiently investigated. To this end, a Joint Sample and Feature importance Assessment (JSFA) model was proposed to simultaneously explore the different impacts of EEG samples and features in mental state recognition, in which the former is based on the self-paced learning technique while the latter is completed by the feature self-weighting technique. The efficacy of JSFA is extensively evaluated on two EEG data sets, i.e., SEED-IV and SEED-VIG. One is a classification task for emotion recognition and the other is a regression task for driving fatigue detection. Experimental results demonstrate that JSFA can effectively identify the importance of different EEG samples and features, leading to enhanced recognition performance of corresponding BCI systems.

ΛCDM-Rastall cosmology revisited: constraints from a recent Quasars datasample

In this paper we study the impact of a recent quasar datasample in the constraint of the free parameters of an extension of general relativity. As a ruler to test, we use Rastall gravity in the context of background cosmology being a simple extension to general relativity. We compare the results from quasars dataset with other known samples such as cosmic chronometers, supernovae of the Ia type, baryon acoustic oscillations, HII galaxies, and also a joint analysis. Results are consistent with the standard cosmological model emphasizing that Rastall gravity is equivalent to general relativity. According to the constraints provided from the joint sample, the age of the Universe is τU=12.601−0.066+0.067 Gyrs and the transition to an accelerated phase occurs at zT=0.620±0.025 in the redshift scale, being only the phase transition consistent with the standard paradigm and having a younger Universe. With the quasars sample, the Universe age differs with that expected in ΛCDM having a result of τU=11.958−0.109+0.139 Gyrs with a transition at zT=0.652±0.032 this last consistent with standard cosmology. A remarkable result is that quasars constraints has the capability to differentiate among general relativity and Rastall gravity due to the result for the parameter λ=−2.231−0.546+0.785 . Moreover, the parameter j under quasars constraints suggests that the cause of the late Universe’s acceleration is a dark energy fluid different from a cosmological constant.

Protective effects of piperlongumine against adjuvant-induced arthritis in rats through modulating OPG/RANKL/NF-κB signaling pathway.

We examined the antirheumatoid effects of piperlongumine (PLM) on rat adjuvant-induced arthritis (AIA) and explored the underlying mechanisms involved. PLM (2.5, 5, and 10 mg/kg) was administered intraperitoneally to AIA rats to assess its effectiveness. Blood, thymus, spleen, ankle joint, and synovial tissue samples were gathered for subsequent analyses, like enzyme-linked immunosorbent assay, thymus/spleen index measurement, ankle joint pathological examination, immunohistochemistry assay, polymerase chain reaction, and western blot assay. Moreover, the involvement of osteoprotegerin (OPG)/receptor activators of nuclear factor κB ligand (RANKL)/nuclear factor-κB (NF-κB) signaling was investigated. PLM effectively relieved inflammation and joint destruction in AIA rats, as indicated by reductions in hind paw swelling, arthritis index, thymus/spleen index, ankle joint pathological damage, production of TNF-α, IL-1β, and IL-6 in both serum and synovium, and osteoclast formation. Also, PLM treatment raised OPG production, reduced RANKL expression, and elevated the OPG/RANKL ratio in synovial tissues. Furthermore, PLM prevented IκBα degradation and phosphorylation, resulting in a reduced expression of the nuclear NF-κB p65 protein in AIA rat synovial tissues. PLM demonstrated strong antiarthritic effects in rats with AIA by influencing the OPG/RANKL/NF-κB signaling pathway, highlighting its potential clinical relevance in treating rheumatoid arthritis.

Dissimilar material joining of densified superwood to aluminum by adhesive bonding

Superwood is a densified wood product that shows promise as a lightweight and renewable alternative for metallic materials. In order for this high-performance new material to be used in multi-material products, it must be able to be joined with other major materials. For example, joining superwood to aluminum would provide a key enabling technology for its use in automotive components since aluminum is presently a major lightweight material for such applications. In this paper, a methacrylate-based adhesive has been identified to provide high lap shear strength (7.5 MPa) for aluminum-to-superwood joints. The aluminum-to-superwood samples were prepared with different amounts of pre-polishing to create openings to the pores in the superwood so adhesive could penetrate into them and create a mechanical interlock, in addition to the hydrogen/chemical bonding at the surface between the methyl methacrylate (MMA) in methacrylate-based adhesive and the cellulose in superwood. For aluminum samples, a thin layer (typically a few nanometers) of oxide film on the surfaces provides hydrogen/chemical bond to MMA structure in the adhesive layer. The failure strength of the superwood-to-aluminum joint sample is about 50% higher than that of natural wood to natural wood joint sample and comparable to that of aluminum-to-aluminum joint sample.

Joint Sample Position Based Noise Filtering and Mean Shift Clustering for Imbalanced Classification Learning

Joint Sample Position Based Noise Filtering and Mean Shift Clustering for Imbalanced Classification Learning

A Novel Technique for Substrate Toughening in Wood Single Lap Joints Using a Zero-Thickness Bio-Adhesive.

In contemporary engineering practices, the utilization of sustainable materials and eco-friendly techniques has gained significant importance. Wooden joints, particularly those created with polyurethan-based bio-adhesives, have garnered significant attention owing to their intrinsic environmental advantages and desirable mechanical properties. In comparison to conventional joining methods, adhesive joints offer distinct benefits such as an enhanced load distribution, reduced stress concentration, and improved aesthetic appeal. In this study, reference and toughened single-lap joint samples were investigated experimentally and numerically under quasi-static loading conditions. The proposed research methodology involves the infusion of a bio-adhesive into the wooden substrate, reinforcing the matrix of its surfaces. This innovative approach was developed to explore a synergetic effect of both wood and bio-adhesive. The experimentally validated results showcase a significant enhancement in joint strength, demonstrating an 85% increase when compared to joints with regular pine substrates. Moreover, the increased delamination thickness observed in toughened joints was found to increase the energy absorption of the joint.

Inspection of press joints based on the analysis of their deformation patterns under local thermal loading

The results of experimental studies of the possibility of using strain gauges under local pulsed thermal loading to evaluate the tension of the press connections of bearing rings with shafts are presented. Samples of press joints with tightness in the range from 38 to 118 microns were made. As a result of the study of the patterns of heat flow propagation in bearing rings and tension samples by contact method and means of thermal imaging, the possibility of separating deformations associated with the influence of temperature on the deformation measurement area and the temperature gradient in the heating area is shown. The methods of inspecting the press joint when exposed to a heater ring with a heat power capacity of 80 kJ and a temperature of 200°C and measuring the deformations of the ring and shaft by an opto-polarizing sensor with a base of 60 mm and a resolution of 2×10 — 7 relative deformations have been experimentally implemented. A correlation has been established between the time of reaching the maximum of local deformations of the shaft with the tightness of the press joints and the sign of deformations of the bearing ring with the tightness of the press fit, the gap between the ring and the shaft.

East Asian and Southern European craniofacial class III phenotype: two sides of the same coin?

The skeletal class III phenotype is a heterogeneous condition in populations of different ethnicities. This study aimed to analyse the joint and ethnicity-specific clustering of morphological features in skeletal class III patients of Asian and European origins. This cross-sectional study involved South Korean and Spanish participants who fulfilled the cephalometric, clinical, and ethnic-related selection criteria. Radiographic records were standardised, calibrated, and measured. A total of 54 skeletal variables were selected for varimax factorial analysis (VFA). Subsequently, a cluster analysis (CA) was performed (mixed method: k-means and hierarchical clustering). Method error and precision were assessed using ICC, Student's t-test, and the Dahlberg formula. A total of 285 Korean and Spanish participants with skeletal class III malocclusions were analysed. After performing VFA and CA, the joint sample revealed three global clusters, and ethnicity-specific analysis revealed four Korean and five Spanish clusters. Cluster_1_global was predominantly Spanish (79.2%) and male (83.01%) and was characterised by a predominantly mesobrachycephalic pattern and a larger cranial base, maxilla, and mandible. Cluster_2_global and Cluster_3_global were mainly South Korean (73.9% and 75.6%, respectively) and depicted opposite phenotypes of mandibular projection and craniofacial pattern. A distinct distribution of Spanish and South Korean participants was observed in the global analysis. Interethnic and interethnic differences were observed, primarily in the cranial base and maxilla size, mandible projection, and craniofacial pattern. Accurate phenotyping, reflecting the complexity of skeletal class III phenotype across diverse populations, is critical for improving diagnostic predictability and future personalised treatment protocols.