Joint Intensity Research Articles

Highly discriminative simultaneous measurement of level, refractive index and temperature of liquid by dual-wavelength fiber ring-cavity laser sensor

In this paper, a novel dual-wavelength fiber laser sensor is proposed and completed by the parallel configuration of modified fiber Bragg grating and modal interferometer. The stable lasing emissions are realized and the comprehensive tests are performed in terms of level, refractive index and temperature of liquid. By the demodulation of joint wavelength and intensity matrix, high-discriminative simultaneous measurement is achieved, and the obtained sensitivities are 19.88 pm/°C, 159.32 dB/RIU and 568 pm/mm, respectively, with the errors below 2.52 %. Additionally, the dynamic field tests are performed, and the limits of detection of 0.15 mm, 0.42°C and 9 × 10-4 RIU are experimentally verified.

A probability theory for filtered ghost imaging

Based on probability density functions, we present a theoretical model to explain filtered ghost imaging (FGI) we first proposed and experimentally demonstrated in 2017 [Opt. Lett. 42 5290 (2017)]. An analytic expression for the joint intensity probability density functions of filtered random speckle fields is derived according to their probability distributions. Moreover, the normalized second-order intensity correlation functions are calculated for the three cases of low-pass, bandpass and high-pass filterings to study the resolution and visibility in the FGI system. Numerical simulations show that the resolution and visibility predicted by our model agree well with the experimental results, which also explains why FGI can achieve a super-resolution image and better visibility than traditional ghost imaging.

GEOLOGY OF PONELO REGION AND SURROUNDINGS, NORTH GORONTALO REGENCY

The research area is one of the islands in the District of Ponelo Islands, North Gorontalo Regency, Gorontalo Province. This study aims to determine the geological conditions of the area using the geological mapping method. The results showed that the geomorphology of the study area was divided into 3 units, namely Lava Flow Hills, Denudasional Hills, and Marin Plains. The stratigraphy of the research area is divided into 5 unofficial units sorted from oldest to youngest, namely Sandstone Unit, Conglomerate Unit, Porphyry Andesite Unit, Basalt Lava Flow Unit (Late Pliocene-Early Pleistocene), and Coastal Sediment Unit (Recent age). The geological structures observed were Shear Fracture, Tension, Sheeting Joint, and Columnar Joint. The geological history of the research area starts from the Late Pliocene to Early Pleistocene where the Lokodidi Formation and Pinogu Volcano Formation were formed, resulting in sandstone and conglomerate units (Lokodidi Formation), porphyry andesite units and basalt lava flow units (Pinogu Volcano Formation). Then the alluvial deposition process which is still ongoing today is the result of weathering of rocks in the research area.

A method for full three-dimensional kinematic analysis of steep rock walls based on high-resolution point cloud data

The predisposition of a slope to generate rockfalls is related to the intensity of rock mass jointing and the geometric arrangement of discontinuities intersecting the rock face. With the increasing use of terrestrial laser scanner (TLS) in rock slope surveying, methods have been proposed to semi-automatically extract the spatial properties of outcropping discontinuities from high-resolution topographic data. The present paper builds upon one of such methods (named DiAna), and extends it to enhance the assessment of rockfall susceptibility over steep rock walls. In particular, a Matlab routine (named DiAna-K) that incorporates a full three-dimensional derivation of kinematic analysis principles is introduced. Kinematic tests for plane, wedge, block toppling, flexural toppling, and free fall failure are formulated by explicitly accounting for the presence of overhanging areas of the rock face as well as varying frictional strengths across different discontinuity sets, planes, or intersections between planes. Results from a test application at an abandoned quarry site highlight the ability of the proposed procedure to provide detailed insights into the kinematic feasibility of structurally controlled instabilities. They also demonstrate the importance of properly defining failure mechanisms over steep (and usually undersampled) topographies in order to derive realistic quantifications of rockfall hazards.

Heterogeneous deformation of friction stir welded aluminum alloy 6061 in tension and high cycle fatigue

PurposeThe investigations provide a basis for the optimization of the alloy 6061-T6 friction stir welding (FSW) process to improve the mechanical properties of welded joints.Design/methodology/approachThe local deformation of the FSW joint in tension and fatigue test were experimentally investigated by digital image correlation (DIC) technique.FindingsThe local stress-strain behaviors of the sub-regions show that the plastic strain always concentrated at the heat affected zone (HAZ) on the advancing side both in tension and high cycle fatigue and eventually leads to the final fracture. The evolution of the plastic strain at very low stress is extremely slow and accounts for most of the total fatigue life. However, the local deformation exhibits a sudden increase just before the fatigue failure.Originality/valueBased on the experimental data, the result indicates that the HAZ is the weakest zone across the weld and the strain localization in high cycle fatigue is very harmful and unpredictable for the FSW joints.

Medical Image Registration Algorithm Based on Bounded Generalized Gaussian Mixture Model.

In this paper, a method for medical image registration based on the bounded generalized Gaussian mixture model is proposed. The bounded generalized Gaussian mixture model is used to approach the joint intensity of source medical images. The mixture model is formulated based on a maximum likelihood framework, and is solved by an expectation-maximization algorithm. The registration performance of the proposed approach on different medical images is verified through extensive computer simulations. Empirical findings confirm that the proposed approach is significantly better than other conventional ones.

GFRP reinforced high performance glass–bolted joints: Development of a simplified finite element-based method for analysis

This paper presents the development of finite element (FE)-based computational models that can be used for predicting the failure load of GFRP-reinforced annealed and heat-strengthened glass–bolted joints. Stress analysis of a single-bolt, single-glass-piece case was first carried out in order to develop the computational models and to establish an appropriate failure criterion for the GFRP-reinforced glass–bolted joints. The computational models were then calibrated against the experimental results reported in a previous experimental study involving reference and reinforced double-lap tension joint test specimens. The paper shows that the failure of both reference and reinforced glass–bolted joints can be predicted using the maximum principal-tensile-stress-based failure of glass. The results also confirm that the use of adhesively bonded GFRP reinforcement has potential to increase the load capacity of the reinforced glass–bolted joints compared to the reference glass–bolted joints.

Prediction model of axially-loaded wood-dowel welding joints by high-speed rotation

Abstract Since rotational wood welding was patented in 1997, this technology has been successfully used in the field of timber structures and furniture. A growing body of literature has investigated the mechanical behaviour of wood-dowel welding joints in tension to study the effect of various factors on welding strength. However, up to now, only two predictive approaches were proposed by researchers, and due to the lack of small samples, they were applied in a limited scope. Therefore, this paper aimed to find a way to establish a multivariate model to compute their carrying capacity. A pull-out test database including 1338 trials from previous literature was used as the basis of modelling. Due to the similarity of joints with glued-in-rod, after evaluating its model validation, the modelling method was applied to the welded joints. The data analysis was carried out to determine the primary influences (such as: rotational speed, predrilled hole diameter, welded length and substrate density). Based on the non-linear regression analysis, a multivariate prediction model was proposed, and results showed positive accuracy with measured values. This study provides a new comprehensive assessment of the withdrawal strength of welded joints, and can help identify future technical guidelines within the wood industry.

VHPKQHR Peptide Modified Ultrasmall Paramagnetic Iron Oxide Nanoparticles Targeting Rheumatoid Arthritis for T1-Weighted Magnetic Resonance Imaging.

Magnetic resonance imaging (MRI) could be the ideal diagnostic modality for early rheumatoid arthritis (RA). Vascular cell adhesion molecule-1 (VCAM-1) is highly expressed in synovial locations in patients with RA, which could be a potential target protein for RA diagnosis. The peptide VHPKQHR (VHP) has a high affinity to VCAM-1. To make the contrast agent to target RA at an early stage, we used VHP and ultrasmall paramagnetic iron oxide (USPIO) to synthesize UVHP (U stands for USPIO) through a chemical reaction with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide. The size of UVHP was 6.7 nm; the potential was −27.7 mV, and the r 2/r 1 value was 1.73. Cytotoxicity assay exhibited that the cell survival rate was higher than 80% at even high concentrations of UVHP (Fe concentration 200 µg/mL), which showed the UVHP has low toxicity. Compared with no TNF-α stimulation, VCAM-1 expression was increased nearly 3-fold when mouse aortic endothelial cells (MAECs) were stimulated with 50 ng/mL TNF-α; cellular Fe uptake was increased very significantly with increasing UVHP concentration under TNF-α treatment; cellular Fe content was 17 times higher under UVHP with Fe concentration 200 µg/mL treating MAECs. These results indicate that UVHP can target overexpression of VCAM-1 at the cellular level. RA mice models were constructed with adjuvant-induced arthritis. In vivo MRI and biodistribution results show that the signal intensity of knee joints was increased significantly and Fe accumulation in RA model mice compared with normal wild-type mice after injecting UVHP 24 h. These results suggest that we have synthesized a simple, low-cost, and less toxic contrast agent UVHP, which targeted VCAM-1 for early-stage RA diagnosis and generates high contrast in T1-weighted MRI.

Fast Patchwise Nonlocal SAR Image Despeckling Using Joint Intensity and Structure Measures

Nonlocal means synthetic aperture radar (SAR) image despeckling approaches have attracted much research attention. However, high computational burden always limits its application in practice, especially using complex similarity measures. We present a fast patchwise nonlocal method using joint intensity and structure measures for SAR image despeckling. Nonlocal methods often define the similarity criterion only based on amplitude or intensity image. In order to preserve structure details, the structure information is also introduced into similarity measure by constructing gradient orientation feature map. The gradient orientation statistical test is performed to determine whether the patches contain the same structural components, and the similar patches are selected through the constant false alarm ratio strategy. Furthermore, we reorganize the patchwise nonlocal despeckling method and accelerate it using fast Fourier transform. Meanwhile, we utilize a Gaussian kernel to aggregate patchwise weights for each pixel in its patch area, so as to reduce the blur effect of classical patchwise nonlocal methods on details. The experiments have demonstrated that the proposed method is an efficient restoration method and has great structure and texture retention ability.

Toward Children's Empathy Ability Analysis: Joint Facial Expression Recognition and Intensity Estimation Using Label Distribution Learning

Empathy ability is one of the most important social communication skills in early childhood development. To analyze the children's empathy ability, facial expression analysis (FEA) is an effective way due to its ability to understand children's emotional states. Previous works mainly focus on recognizing the facial expression categories yet fail to estimate expression intensity, the latter of which is more important for fine-grained emotion analysis. To this end, this article first proposes to analyze children's empathy ability with both the categories and the intensities of facial expressions. A novel FEA method based on intensity label distribution learning is presented, which aims to recognize expression categories and estimate their intensity levels in an end-to-end framework. First, the intensity label distribution is generated for each frame in the expression sequence using a linear interpolation estimation and a Gaussian function to address the lack of reasonable annotations for expression intensity. Then, the extended intensity label distribution is presented to automatically encode the expression intensity in a multidimensional expression space, which aims to integrate the expression recognition and intensity estimation into a unified framework as well as boost the expression recognition performance by suppressing the variations in appearance caused by intensity and by emphasizing those variations among weak expressions. Finally, a Siamese-like convolutional neural network is presented to learn the expression model from a pair of frames that includes an expressive frame and its corresponding neutral frame using the extended intensity label distribution as the supervised information, thus effectively eliminating the expression-unrelated information's influence on FEA. Numerous experiments validate that the proposed method is promising in analysis of the differences in empathy ability between typically developing children and children with autism spectrum disorder.

Pre-folding fracturing in a foredeep environment: insights from the Carseolani Mountains (central Apennines, Italy)

AbstractBedding-perpendicular joints striking parallel (longitudinal) and perpendicular (transverse) to both the axis of the hosting anticline and the trend of the foredeep-belt system are widely recognized in fold-and-thrust belts. Their occurrence has been commonly attributed to folding-related processes, such as syn-folding outer-arc extension, although they can also be consistent with a pre-folding foredeep-related fracturing stage. Here we report the pre-folding fracture pattern affecting the Pietrasecca Anticline, in the central Apennines (Italy), resolved by a detailed field structural analysis. Field observations, scan-lines and interpretation of virtual outcrops were used to study the intensity, distribution and the orientations of fracture pattern along the anticline. The fracture pattern of the Pietrasecca Anticline consists of longitudinal and transverse joints, oriented approximately perpendicular to bedding, and of a pre-folding longitudinal pressure-solution cleavage set, which is oblique to bedding regardless of the bedding dip. Cross-cutting relationships show that joints predated the development of the pressure-solution cleavage. Furthermore, joint intensity does not relate to the structural position along the anticline. Taken together, these observations suggest that jointing occurred in a foredeep environment before the Pietrasecca Anticline growth. Our work further demonstrates that joints striking parallel and orthogonal to the main fold axis do not necessarily represent syn-folding deformation structures.

Experimental Investigation and Numerical Simulation of C-Shape Thin-Walled Steel Profile Joints

The versatility of steel, its high resistance in relation to its low mass, as well as the easily accessible technology in the context of using recyclable materials and the low negative impact on the environment represent important arguments in using thin-walled steel profiles to make structures for buildings with a low height regime. This paper presents the results of an experimental program that investigated the behavior of three types of joints in a T-shape form made of thin-walled steel profiles to make shear wall panels or truss beam floors. Due to the small dimensions of the C-profiles of 89 × 41 × 12 × 1 mm, and of the technology of their joining, manufacturers prefer the hinged connections of elements with self-drilling screws. The purpose of the research presented in this paper is to assess the maximum capacity of the joints, the elastic and post-elastic behavior until failure, and also the mechanisms failure. The types of joints analyzed are commonly used in the production of structural systems for houses. The experimental program, which consisted of testing 5 specimens for each type of joint in tension (shear on screws), showed different behavior in terms of load-displacement. The experimental, tested models were analyzed by finite element simulations in an ANSYS nonlinear static structure with 3D solid models. The materials were defined by a bilinear true stress–strain curve obtained after some experimental tensile tests of the steel. The results of the experimental tests showed that the main failure mechanism is a yielding of the holes where the screws were mounted and a shearing of the profile walls. Adding an additional screw on each side increases the capacity of the joints, but not until a yield loss is obtained. In conclusion, it is shown that the solution is suitable for a low level of loading in a static manner; however, additional studies are necessary in order to develop and verify other solutions, thus improving the strength of the connection.

Development of mid-span tension joint and tension clamp for large section energy-saving conductor in 1100kV UHV DC transmission

For the large cross-section energy-saving conductor JL1/LHA1-935/415 - 63/28 used in ±1100kV UHV DC project, the matching tension clamp and mid-span tension joint were designed. Based on the statistical analysis of the grip strength test results, the optimized design of the tension clamp and mid-span tension joint were completed. The grip strength after optimization is more than 95% RTS, which meets the requirements of standard. The results show that the developed tension clamps and midspan tension joints have excellent performance and could be used in actual engineering.

Relationship Between Pain and Sedentary Behavior in Rheumatoid Arthritis Patients: A Cross-Sectional Study.

Despite the known benefits of physical activity, high numbers of individuals with rheumatoid arthritis (RA) remain physically inactive and sedentary. Little is known about the determinants of sedentary behavior (SB) in RA. This cross-sectional study was undertaken to examine a range of pain characteristics and RA-related symptoms and their relationship with objectively measured SB. In total, 76 adults with RA wore an activPAL4 accelerometer (PAL Technologies) over a 7-day period. Pain characteristics (pain intensity, painful joint count, nonarticular pain), fatigue, sleep, depression, anxiety, and disease activity were assessed. Analyses were first conducted to evaluate correlations with sedentary time. The independent contribution of pain characteristics to variation in SB was analyzed with multivariable linear regression (adjusted for demographic data and disease activity). Participants with valid accelerometer data (n = 72) spent a mean ± SD of 533.7 ± 100.1 minutes/day in SB. Positive associations with daily SB were found for pain intensity (r = 0.31, P < 0.01) and number of painful joints (r = 0.24, P < 0.05) but not nonarticular pain. In multivariable analyses, pain characteristics were not independently associated with SB. Analyses indicated that disease activity had an indirect association with SB mediated by pain intensity. Other correlates of daily SB included anxiety and depression but not fatigue or sleep. Results suggest that while pain and other RA-related factors do play a role in SB, they do not appear to have a significant influence after accounting for other variables. Future research should investigate SB and the role of factors unrelated to the symptoms of RA.

Strength of 316L Stainless Steel Single-Lap Joints Brazed with Ni-Based Metallic Glass Foils for Corrosive Environments

In brazing, the choice of base metal, brazing filler metal (BFM), and braze process conditions involves complex tradeoffs among cost, mechanical strength, corrosion resistance, and others. In this work, the tradeoff between strength and corrosion resistance of 316L stainless steel joints brazed with a newer “very corrosion-resistant” Ni-Cr-P-Mo-Si BFM and a more established “corrosion-resistant” Ni-Cr-Si-B BFM is quantitatively analyzed. Corrosion tests and microstructural analyses were performed using common practices. Joint strength was evaluated by testing brazed single-lap joints (SLJs) in tension following standardized procedures. However, conventional interpretations were found to be inadequate for quantitative comparisons. Therefore, the SLJ stress state was analyzed in detail and a complete interpretation was developed. Joint strength is shown to be determined by the SLJ geometry, base metal properties, and braze microstructure. This analysis was used to explain the occurrence of different failure modes (fast fracture, peeling, and base metal failure) and to make suggestions for improved methods for conducting and analyzing brazed SLJ tensile tests. The newer BFM is shown to provide significantly better corrosion resistance for a moderate reduction in mechanical strength.

Biomechanical Changes of Adjacent and Fixed Segments Through Cortical Bone Trajectory Screw Fixation versus Traditional Trajectory Screw Fixation in the Lumbar Spine: A Finite Element Analysis

The finite element method was used to investigate the biomechanical adjustments of adjacent and fixed segments after lumbar fusion and fixation with traditional trajectory (TT) and cortical bone trajectory (CBT) screws. The model used was a validated nonlinearly L3-S1 finite element model. Interbody fusion cages and 2 types of screws were used to work on the L4-L5. To simulate flexion, extension, lateral bending, and axial rotation, all models were loaded in 3 planes with a compressive pre-load of 400 N and a bending moment of 7.5 N/m. Under various loading conditions, the range of motion (ROM), peak Von Mises stress of the vertebral body, stress of the intervertebral disc, stress of the facet joints, stress of the endplate, and stress of internal fixation were compared. In all instrumentation models, the ROM at fixed segments decreased. At adjacent segments, the ROM of the CBT model was greater than that of the TT model. The CBT model had a greater peak Von Mises stress of the L4 and L5 vertebral bodies, as well as greater stress of internal fixation, than the TT model. Furthermore, as compared with the TT model, the CBT model's facet joint and endplate stress were lower at fixed segments but higher at adjacent segments. The stress on the L3-L4 and L5-S1 intervertebral discs in the CBT and TT models, on the other hand, was nearly equivalent. At the fixed section, CBT may provide slightly better stability, endplate tension, and facet joint stress than TT. The greater ROM, endplate stress, and facet joint stress of CBT in adjacent segments, on the other hand, should be taken into account in the future.

Treatment of acquired patella baja by proximalization tibial tubercle osteotomy significantly improved knee joint function but overall patient-reported outcome measures remain diminished after two to four years of follow-up

Acquired patella baja is often characterized by painful limitation of knee joint range of motion and anterior knee pain (AKP). Only few studies have evaluated the effectiveness of surgical treatment in terms of patient-reported outcome measures (PROM's) and sports activity. Thus, the goal of this study was to assess PROM's and sports activity after proximalization tibial tubercle osteotomy (P-TTO) in patients with symptomatic patella baja. Between 2016 and 2018, a case series of 11 patients (male/female 4/7; age 48 ± 12years) were treated by P-TTO and were retrospectively evaluated after a mean of 33.7months (range 24-51months). The Tegner activity score and the Kujala anterior knee pain scale were used in addition to a visual analogue scale (VAS; 0-10) regarding self-reported knee joint function and intensity of AKP. Radiographic assessment included the measure of patellar height using the Caton-Deschamps (CD) and Blackburne-Peel (BP) index. Postoperatively both the CD and the BP index increased to normality (p < 0.0001; p = 0.0012). Knee joint flexion improved from 100 ± 32° preoperatively to 123 ± 14° postoperatively (p = 0.0235). AKP decreased from 6.5 ± 2.1 points preoperatively to 3.7 ± 2.1 points postoperatively (p = 0.0061). This was accompanied by a significant increase in self-reported knee joint function from 1.8 ± 1.2 points preoperatively to 6.8 ± 2.3 points postoperatively (p = 0.0001) and an increase of the Tegner activity score from 1.8 ± 1.6 points preoperatively to 3.9 ± 1.5 points postoperatively (p = 0.0074). Although the Kujala score improved significantly by an average of 31.55 points (p = 0.001) overall score results remained reduced at 65.6 ± 17.9 points at final follow-up. P-TTO yielded significant improvements in terms of AKP, subjective knee joint function and sports activity. However, the overall Kujala score results remained reduced, indicating that surgical correction of patellar height is not sufficient to relieve all patients' complaints. In addition, the incidence of postoperative complications was high.

Sinus, disabling tension-type, and temporomandibular joint headaches.

Clinicians frequently face questions from headache patients regarding the roles played by sinus issues, muscle tension, and temporomandibular joint (TMJ) problems. This review highlights new concepts regarding the diagnosis and management of these headache conditions and their differentiation from migraine. Recent research has clarified the roles played by pathology in the paranasal sinuses and TMJ in patients reporting headache. Additional information from physiologic studies in patients with tension-type headache (TTH) has improved the understanding of this condition. Improved understanding of sinus headache, disabling TTH, and TMJ headache and their differentiation from migraine will lead to reductions in unnecessary diagnostic procedures and unwarranted medical and surgical procedures. More expedient recognition of the origin of headache should lead to improved therapeutic outcomes.

GFRP reinforced high performance glass–bolted joints: Concept and experimental characterisation

This paper presents the results of an experimental investigation into the use of externally-bonded Glass Fibre Reinforced Polymer (GFRP) strips as a means of improving the load capacity and delayed failure characteristics of glass-bolted joints. The peak load and the failure behaviour of GFRP reinforced bolted joints in annealed, heat-strengthened and tempered glass were investigated using the experiments of double-lap tension joint configurations. The results were compared with that of reference unreinforced joints, and bolted joints in commercially available laminated-annealed glass. The paper shows that GFRP reinforcement ensured significantly enhanced structural performances of the joints in annealed and heat-strengthened glass. Although the bolted joints in tempered glass showed the highest load capacity, the joints failed with no ductility where tempered glass shattered into small dices.