Protrusion Height Research Articles

Splitting behavior of Janus drop impact on protrusion structure

Handling tiny liquid volumes as drops is important for applications, including biochip or liquid spraying systems. Splitting of a compound drop is a challenging task in the industrial fields, but the underlying mechanism is not clearly revealed. Here, we demonstrate the dynamic characteristics of the bounce and separation of Janus drops on protrusions by using a numerical method. A regime map for the separation rate between low- and high-viscosity components is investigated for various viscosity ratios and Weber numbers, which is discussed in terms of the formation of a ring and the reduction in residence time. We predict off-centered drop impact on the protrusion structure under various offset distances and characterize the impact behavior into the ring and bifurcation bouncing. We investigate how the separation rate is affected by the protrusion's height and width. The rim dynamics occurring when a liquid film is punctured are discussed by quantifying the evolutions of the shapes and axial momenta of the drops. We expect that the splitting of the compound drop on a defect can create possibilities for the efficient control of drop manipulation and fluid purification.

Effect of single and multiple protrusions on thermal performance of slot jet impingement with curved surface

The current study uses numerical methods to evaluate the thermal and flow characteristics of air jet impinging on concave surfaces with single and multiple protrusions on a surface. The impact of different operating parameters is also studied, including Reynolds number, jet inclination angle and nozzle-to-plate distance (H/B). No significant improvement in the overall thermal performance is noted with a single protrusion on the surface, although a higher heat transfer is observed in the stagnation zone. On the other side, the multiple protrusions on the surface have shown an increase or decrease in the overall thermal performance of jet impingement depending on protrusion diameter and height. The maximum improvement in the overall Nu is noted up to 19 % for the multi-protruded surface at H/B = 6 with orthogonal jet impingement. An oblique jet decreased the overall thermal performance compared to the orthogonal jet, regardless of the jet inclination angle.

Numerical simulation on flow and heat transfer mechanism of n-decane in tube with round protrusions under supercritical pressure

The numerical simulation about flow and heat transfer characteristics of n-decane under supercritical pressure in the tube with round protrusions is researched in this study. The heat transfer enhancement mechanism of protuberant tube is conducted by realizable k-ε model. The average outer wall temperature of protuberant tube is reduced by approximately 60–80 K and the Nu is 45–55 greater rather than smooth structure within the operating cases. When comparing with smooth tube, the thermal performance of protuberant tube increased by 62.5%–81.4%, and the whole heat transfer performance increased by 15.6%–32.4%. The obvious heat transfer enhancement of protuberant tube is attributed to the effective destruction of thermal and flow boundary layer. Forced mixing effects of protrusions enhance flow and heat transfer further. Besides, the effects of protrusion height, pitch and circumferential number on flow and heat transfer performance are also studied. The results reveal that the increase of protrusion height and circumferential number can simultaneously rise the Nuc/Nus and fc/fs, while the increase of protrusion pitch is contrary. Among all working conditions, the protuberant tube of H = 0.5 mm, P = 4 mm and Nc = 6 obtains the largest PEC = 1.35.

Modeling of material removal depth in robot abrasive belt grinding based on energy conversion

Accurate material removal is of great significance to ensure the machining accuracy of robot abrasive belt grinding (RABG). In this paper, a material removal depth (MRD) model for RABG of superalloy is proposed based on the energy conversion in grinding. Based on the characteristics of the shape and protrusion height distribution of grits, the energy conversion equation is established through the force analysis of the interference between grits and workpiece, and then the expression of material removal depth is derived by combining the Hertz elastic contact theory. In addition, in view of the change of belt coverage ratio caused by the structured belt wear, the expression of grit distribution density considering belt wear is obtained through the Archard wear model and applied to the MRD model. The MRD model is evaluated by the experiment, and the results show that the proposed model has good prediction ability. Furthermore, the effects of grinding parameters on MRD are analyzed, and the grinding parameters that take into account both the MRD and surface quality are discussed. This research provides a theoretical reference for material removal research in RABG.

Impact of renal sinus protrusions on achieving trifecta in robot-assisted partial nephrectomy.

The objective of this work is to assess the relationship between the morphological characteristics of a central tumour and the perioperative outcomes of robot-assisted partial nephrectomy (RAPN). We retrospectively analysed the data from 186 patients with central tumours involving the renal sinus, who underwent RAPN in a single-centre study between February 2015 and June 2022. All cases were assigned a RENAL nephrometry score based on preoperative images. The shape of the protruding portion of the tumour was classified into four types: 'flat', 'spherical', 'single-hump', and 'complex-hump', and was independently assessed by two readers. The trifecta is defined as the warm ischemia time within 25 min, negative surgical margins, and no major postoperative complications. Univariate and multivariate analyses were performed to identify the factors associated with the failing trifecta. Trifecta was achieved in 113 cases (60.8%), and the achievement rate in flat, spherical, single-hump, and complex-hump types was 83.3%, 74.5%, 64.3%, and 21.3%, respectively. Prolonged warm ischemia time was the primary cause of the failure to achieve the trifecta. The rate of positive surgical margins and upstage to pathological T3a was greater for complex humps while the rate of major complications and postoperative GFR preservation did not differ between shapes. On multivariate analysis for failing trifecta achievement, the complex-hump protrusion was found to be an independent positive predictor (odds ratio: 15.8; p< 0.001), whereas the height and width of protrusion were not significantly related. The degree of difficulty varied among central tumours, and it was not possible to precisely measure it with existing scoring systems. Complex-hump protrusions strongly correlate with failure to achieve the trifecta. Preoperative assessment of the morphology of protrusion is useful for predicting outcomes.

The story of a summit nucleus: hillslope boulders and their effect on erosional patterns and landscape morphology in the Chilean Coastal Cordillera

Abstract. While landscapes are broadly sculpted by tectonics and climate, on a catchment scale, sediment size can regulate hillslope denudation rates and thereby influence the location of topographic highs and valleys. In this work, we used in situ 10Be cosmogenic radionuclide analysis to measure the denudation rates of bedrock, boulders, and soil in three granitic landscapes with different climates in Chile. We hypothesize that bedrock and boulders affect differential denudation by denuding more slowly than the surrounding soil; the null hypothesis is that no difference exists between soil and boulder or bedrock denudation rates. To evaluate denudation rates, we present a simple model that assesses differential denudation of boulders and the surrounding soil by evaluating boulder protrusion height against a two-stage erosion model and measured 10Be concentrations of boulder tops. We found that hillslope bedrock and boulders consistently denude more slowly than soil in two out of three of our field sites, which have a humid and a semi-arid climate: denudation rates range from ∼5 to 15 m Myr−1 for bedrock and boulders and from ∼8 to 20 m Myr−1 for soil. Furthermore, across a bedrock ridge at the humid site, denudation rates increase with increasing fracture density. At our lower-sloping field sites, boulders and bedrock appear to be similarly immobile based on similar 10Be concentrations. However, in the site with a Mediterranean climate, steeper slopes allow for higher denudation rates for both soil and boulders (∼40–140 m Myr−1), while the bedrock denudation rate remains low (∼22 m Myr−1). Our findings suggest that unfractured bedrock patches and large hillslope boulders affect landscape morphology by inducing differential denudation in lower-sloping landscapes. When occurring long enough, such differential denudation should lead to topographic highs and lows controlled by bedrock exposure and hillslope sediment size, which are both a function of fracture density. We further examined our field sites for fracture control on landscape morphology by comparing fracture, fault, and stream orientations, with the hypothesis that bedrock fracturing leaves bedrock more susceptible to denudation. Similar orientations of fractures, faults, and streams further support the idea that tectonically induced bedrock fracturing guides fluvial incision and accelerates denudation by reducing hillslope sediment size.

Three-dimensional Anthropometric Analysis of Racial and Ethnic Differences in Unilateral and Bilateral Cleft Nasal Deformity.

This study used three-dimensional measurements to provide a nasolabial analysis of patients with unilateral cleft lip and palate (UCLP), bilateral cleft lip and palate (BCLP), and controls across different races and ethnicities. A retrospective comparative study. Tertiary care pediatric institution. The study included 90 patients with UCLP, 43 patients with BCLP, and 90 matched controls. Patients are separated as self-identified Caucasian, Hispanic, or African American. Nasal length, nasal protrusion, columellar height, columellar width, tip width, alar width, alar base width, nasolabial angle, upper lip length, philtrum length, nostril height, and nostril width. All UCLP groups had significantly greater columella and tip widths and decreased nasolabial angles than controls. All BCLP groups had significantly greater columella width, tip width, nasolabial angle, and nostril widths. Upper lip length, philtrum length, and nostril height were significantly decreased in BCLP compared to controls. Across UCLP groups, African Americans had significantly decreased nasal protrusion and columella height and a significantly increased columella width compared to Caucasians and Hispanics. Alar and alar base widths were significantly different between all groups. Across BCLP groups, the Caucasian nostril width was significantly less than the African Americans. These findings suggest that when correcting nasolabial characteristics in patients with cleft lip, it is important to consider racial and ethnic differences to achieve a normal appearance. Specifically, goals for alar width, alar base width, nasal tip, and projection should be tailored to the patient's race and ethnicity.

Numerical study on the effects of cylindrical roughness on heat transfer performance and entropy generation of supercritical carbon dioxide in vertical tubes

In view of heat transfer deterioration(HTD), rough tubes may help improve heat transfer performance and reduce irreversibility simultaneously. The effects of the tube with cylindrical roughness (CRT) on heat transfer and entropy generation of S-CO2 are studied numerically. The considered variables are the protrusion's axial spacing(l/L), height(e/d), width(w/d) and circumferential angle(α/2π), in the range of l/L = 1/50∼1, e/d = 0∼0.0656, w/d = 0∼0.153 and α/2π=1/12∼1. The results show CRT helps improve heat transfer, the heat transfer coefficient increases about 20% as e/d, w/d increases or l/L, α/2π decreases. Regarding irreversibility, on the one hand, CRT helps entropy generation drop in the HTD area. With e/d, w/d increasing or l/L, α/2π decreasing, entropy generation in the HTD area decreases. On the other hand, CRT causes entropy generation to rise in the non-HTD area. In the non-HTD area, with l/L increasing, entropy generation increases, with e/d, w/d increasing or α/2π decreasing, entropy generation initially increases and then essentially remains constant. The overall entropy generation through the whole tube is the combination of these two areas. In some ranges, the heat transfer coefficient and overall entropy generation of CRT are both better than those of smooth tubes. Because the disturbance effect of protrusions promotes the generation and diffusion of turbulent kinetic energy, thereby alleviating heat transfer deterioration. This study may provide references for S-CO2 heat transfer enhancement and the design of related components.

Wear performance of the Fe-Ni-WC-based impregnated diamond bit with Mo2C-coated diamonds: Effect of the interface layer

With the increased difficulty of drilling into hard rock in the petroleum industry, the demand for higher performance and efficiency of impregnated diamond bits (IDB) has risen sharply. This paper describes the effect of Mo2C coatings on the wear properties and working efficiency in Fe-Ni-WC-based IDBs. The Mo2C-coated diamonds were obtained via the molten salts method. The diamond/Fe-Ni-WC IDBs were prepared by vacuum hot-press sintering method. Laboratory drilling tests of IDBs were carried out to evaluate the wear performance of the two drilling bits. An ultra-depth field 3D imaging microscope was performed to measure the protrusion height of diamond particles on the bottom surface of IDBs. The results manifested that the addition of the Mo2C coating contributed to increasing the protrusion height of diamonds, meaning the enhancement of the interface strength between the diamonds and matrix. The drilling rate of the Fe-Ni-WC-based IDB with Mo2C-coated diamonds is 18% higher than that of Fe-Ni-WC-based IDB with uncoated diamonds, accompanied by increased wear loss.

Drawing–upsetting–extrusion–clinching of high-strength steel and aluminum alloy

To realize good point connection between high-strength steel and aluminum alloy, a process of drawing–upsetting–extrusion–clinching was proposed. First, the sheets were drawn; then, the bottom of the protrusion part was extruded, forming the necessary initial interlock; and finally, the protrusion part was reverse press clinched, forming a certain height of the clinched head. Taking DP980 high-strength steel and Al5083 aluminum alloy as the connection objects and using the method of numerical simulation combined with experimental test, the mold was made, and the experiment was carried out on the basis of numerical simulation. The experimental results proved the feasibility of the process and the effectiveness of the numerical model. The simulation and experimental results show that the necessary interlock in the drawing–upsetting–extrusion stage is the premise of effective connection. The relative protrusion height should be around 55.6% after reverse-press-clinching. The best comprehensive mechanical properties measured by strength test were shear resistance of 2644 N, fatigue life of 24,535 times and peel resistance of 1522 N. Through failure analysis, the relationship between the interlock Tu and the neck thickness Tn of the joint with the best comprehensive mechanical properties was established as Tu = 0.35Tn. The design method of die and process parameters when the sheet thickness changes was researched by numerical simulation. The results show that the clearance between the punch and the die and the bottom thickness are directly proportional to the sheet thickness, and the drawing depth is directly proportional to the punch radius.

Oilstone Processing and Its Impact on the Surface Texture of Cylinder Bore

AbstractHoning is one of the abrasive-based machining processes to remove material through the asperity interaction between numerous stochastic grains distributed on oilstone (also called honing stone) and workpiece. Therefore, the oilstone surface topography characterized by grain morphology, size, posture and position distribution, protrusion heights and etc. is of great significance to understand honing mechanism in terms of establishing an accurate kinematic model and further analyzing the oilstone property's impact on honing process and honed surface texture characteristics including groove density, roughness heights, and plateau/valley amplitudes. Conventionally, two typical approaches have been employed to establish the surface topography of abrasive-based cutting tools: experimentally microscopic observation and backward modeling/simulation from the assumed ideal distribution laws such as Gaussian or uniform distribution for stochastic grain characteristics. The first method is usually time-consuming and only measures surface topography within rather small area, whereas the second one is highly dependent on the authenticity of assumed statistical distribution laws. To overcome these weaknesses, the research proposed a functional forward method (FFM) to accurately predict surface topography of oilstone based on simulating its manufacturing processes in succession to avoid distributional assumptions and geometrical simplification. The methodology takes into consideration five important stochastic characteristics of oilstone including grain morphology, size, posture, position distribution, and grain wear during honing process, to guarantee the credibility, authenticity, and generality of the surface topography generated from honing. Based on the oilstone surface topography, the kinematic simulation method (KISM) was applied to analyze the honed surface texture characteristics of cylinder bore with oilstone samples under different stirring times. Therefore, the methodology bridges oilstone manufacturing parameters, oilstone surface topography, and further the honed surface texture to provide a fresh insight into the parameter’s optimization of the oilstone manufacturing process by achieving a better control on the honed surface texture of the cylinder bore.

Modeling and Characterization of Annealing-Induced Cu Protrusion of TSVs With Polyimide Liner Considering Diffusion Creep Behavior

Polymer liner has been used in through-silicon-vias (TSVs) for smaller parasitic capacitance and better thermo-mechanical performance. For the application in heterogeneous integrated systems, it is critical to study the thermal reliability of such TSVs in both theoretical modeling and experimental characterization. Among the numerous reliability challenges, the Cu protrusion phenomenon of TSVs is one of the most severe issues, which can lead to cracks and delamination in integrated systems. In this article, the annealing-induced Cu protrusion of polyimide (PI) liner TSVs is studied by experiments and simulations. PI-TSVs are fabricated and the Cu protrusion at various annealing conditions is characterized. Finite element analysis (FEA) is carefully carried out taking into account the diffusion creep rate model, and the deviations between FEA and experiment results of protrusion heights are less than 3%. Besides, the deformation procedure and the creep behavior of Cu pillars during annealing are analyzed. Based on the proposed FEA model, comprehensive parametric analyses are conducted to study the effects of different annealing conditions on the Cu protrusion heights, which are helpful to understand and improve the thermal reliability of PI-TSVs.

Sustainability assessment of solar thermal collector using jet impingement

The aluminum absorber plate of the solar thermal collector faces a drawback of lower convective heat transfer coefficient. The focus of overcoming the low heat transfer leads to use of hemispherical protrusion on heated aluminum surface with integration of jet impingement in a rectangular channel. The techniques used to enhance the thermal performance leads to a pressure drop penalty with it. Thus, in order to determine the usefulness of the thermal system harvesting the solar energy the present investigation is taken up. The geometric parameters are used to determine the Sustainability index, Waste energy ratio and Improvement potential. The investigated range of parameters for present study are Relative protrusion diameter to protrusion height ratio (dpr/epr) from 1 to 2, Relative streamwise pitch (X/Dh) from 0.869 to 2.173 and Relative spanwise pitch (Y/Dh) in the range of 0.434–1.08. The present analysis of the thermal system having aluminum absorber fetches the magnitude of Sustainability index, Waste energy ratio and Improvement potential of 1.034. 0.984 and 10.8, respectively for better understanding of the effectiveness of the system in a wide spectrum.

Holding time effect on mechanical properties and protrusion behaviors of through silicon via copper under various annealing processes

The thermomechanical reliabilities of TSV based structures are closely affected by the protrusion deformation, stress-strain constitutive behavior and microstructure evolution of TSV-Cu under various thermal loadings. In this study, the stress-strain constitutive curves of TSV-Cu under various annealing conditions considering holding time effect are acquired by the nanoindentation test and finite element (FE) reverse analysis. The yielding softening in stress-strain curves is found if the holding time is less than 90 min. However, the stable stress-strain curves are obtained as holding time exceeds 90 min. Furthermore, the mechanisms of softening and stability in stress-strain curves are revealed by observing the microstructure evolution of TSV-Cu with a wide range of holding time. In addition, the relationships among protrusion height, constitutive curves as well as microstructure parameter of TSV-Cu with different annealing holding time are built. This study provides an intrinsic insight on the correlations of deformation, constitutive curves, and microstructure for TSV-Cu annealing processes considering holding time effect.

Effect of leading-edge protrusion shapes for passive flow control measure on wind turbine blades

In the present study, protrusions in the leading edge of the NACA 4415 airfoil were incorporated as a passive flow control measure on the wind turbine blades. Three airfoil models: unmodified leading-edge (ULE), spherical leading-edge protrusion (SLEP), and triangular leading-edge protrusion (TLEP), were investigated experimentally. Thereafter, CFD investigations were carried out using ANSYS 14.0 simulation tool to observe the flow characteristics around the airfoils. Further, LEP-based passive design was applied on a horizontal axis wind turbine (HAWT) to investigate its performance. An amplitude (A) of 1% of the chord length (C) was considered as the height of protrusion, while a distance of 0.25C was maintained between the protrusions to fabricate the experimental models. The study was performed at a low Reynolds number (Re) of 1.5 × 105 for a wide angle of attack (α) of 0°–20°. The experimental results demonstrate that the SLEP model has a higher lift coefficient at α ≥ 18°, whereas the TLEP model performs poorly when compared with the ULE model. The instantaneous lift coefficient plot indicates that the SLEP model generates a more stable force at a higher angle of attack. The computational analysis reveals that a larger primary circulation (extended till 0.2C) is observed in the ULE model at a post-stall angle of attack (α = 18°), indicating early flow separation. Whereas, in the SLEP and TLEP models, it is extended to 0.70C and 0.54C, respectively, indicating the best flow controlling measures achieved by using the SLEP model. The investigations of HAWT rotors with LEP revealed that SLEP HAWT exhibit 8.2% more power coefficient than ULE HAWT.

Identification of Tool Life Stages and Redressing Criterion for Polycrystalline Diamond Micro-Grinding Tools Using a Machine Learning Approach

Abstract Interactions of wear debris at the tool-workpiece interface in micro-grinding are quite random which leads to considerable variability in the working life of similar tools. It is not possible to capture the effect of wear debris entrapment on process signals using the available physics-based model, which makes it difficult to identify the tool life stages. The present study highlights the wear pattern and life stages of a polycrystalline diamond tool (PCD) during micro-grinding of BK7 glass. Based on the time and frequency domain cutting force features and tool surface morphology, life of a typical PCD tool could be divided into three stages viz., abrasion stage (0–23% of total tool life), loading stage (23–77% of total tool life), and chipping stage (77–100% of total tool life). A machine learning model utilizing support vector machine (SVM) could predict the life stages of a tool with a prediction accuracy of around 80.5%, and the wear pattern of a new tool coming into service becomes more deterministic on using more datasets for model training. A new modified textured PCD tool, which provided better tool-work interaction and improved debris disposal, shows little variation in cutting force features across many similar design tools which enabled identifying the life stages with higher confidence. Prognosis of tool redressing criterion enabled timely redressing of the tool which led to refined tool surface condition, such as increased number of available chip pockets, greater protrusion height of the abrasives, and lowered roughness of the machined surface.

Tangential dressing of diamond grinding wheel by femto-second pulsed laser with Bessel beam

Bronze bonded diamond grinding wheel is widely used in grinding hard and brittle materials. In order to improve the profile accuracy of the grinding wheel, an ultra-fast laser dressing method with Bessel beam for diamond grinding wheel is proposed in this study. The coarse grain (100 #) bronze bonded diamond grinding wheel is tangentially shaped by laser dressing. By comparing the profile and surface quality of the grinding wheel dressed with Gaussian laser beam and Bessel laser beam under different defocusing amounts, it is found that Bessel beam can dress the grinding wheel in the focal depth of 1.2 mm, which is three times of traditional Gaussian beam. The ablation thresholds of bronze binder and diamond under Bessel beam are obtained through experiments and theoretical calculations. The results show that when the laser power density is 3.75 × 105 W/cm2 – 4.75 × 105 W/cm2 and the axial scanning speed of the laser is 0.03 mm/min, the diamond grit has an enough protrusion height, and the runout of the grinding wheel is reduced to about 6 μm. When the wheel speed is too low, it will reduce the overlap rate of axial scanning trajectory and reduce the removal efficiency of material.

Effects of textured insoles and elastic braces on dynamic stability in patients with functional ankle instability

BackgroundFunctional ankle instability (FAI) is a common condition that affects individuals who have experienced previous ankle sprains. Textured insoles and elastic ankle braces have been previously used as interventions to improve stability in FAI patients. However, the optimal combination of these interventions has not been fully explored. The objective of this study was to investigate the effects of different types of textured insoles and elastic ankle braces on the dynamic stability of individuals diagnosed with FAI.MethodsThe study involved 18 FAI patients who performed single-leg landing tasks with and without wearing an eight-band elastic ankle brace while wearing textured insoles with protrusion heights of 0 mm, 1 mm, and 2 mm. The dynamic posture stability index (DPSI) and its components in the anterior-posterior (APSI), mediolateral (MLSI) and vertical (VSI) directions were calculated from the ground reaction force collected from the Kistler force plate during the first three seconds of the landing tasks.ResultsA significant interaction was found between textured insole type and ankle brace for DPSI (P = 0.026), APSI (P = 0.001), and VSI (P = 0.021). However, no significant interaction was observed for MLSI (P = 0.555). With elastic ankle braces, textured insoles with 1-mm protrusions significantly enhanced anterior-posterior, mediolateral, vertical, and overall stability compared to textured insoles with no and 2 mm protrusions (P < 0.05). Without elastic ankle braces, textured insoles with 1-mm protrusions significantly improved the anterior-posterior (P = 0.012) and overall stability (P = 0.014) of FAI patients compared to smooth insoles.ConclusionsThe combination of textured insoles with 1-mm protrusion heights and an elastic ankle brace could enhance the dynamic stability of individuals with FAI, potentially mitigating the risk of ankle sprains.

Evaluation of the Therapeutic Effect of Contrast-Enhanced Ultrasound on Different Types of Knee Osteoarthritis in the Elderly

Objective: To evaluate the curative effect of the Traditional Chinese Medicine (TCM) external therapy on knee osteoarthritis patients with different TCM constitutions using musculoskeletal ultrasonography and contrast-enhanced ultrasonography, and to explore the application value of contrast-enhanced ultrasonography in knee joint diseases. Methods: A total of 57 patients diagnosed with knee osteoarthritis in Shaanxi University of Traditional Chinese Medicine from December 2019 to May 2021 were collected, and they were divided into qi stagnation and blood stasis type group (23 cases) and cold-dampness obstruction type group (34 cases) according to the traditional Chinese medicine method. All patients were given acupuncture combined with TCM fumigation and washing. All patients underwent musculoskeletal ultrasonography and contrast-enhanced ultrasonography before and after treatment, observed and recorded relevant data, and compared the treatment effects between the two groups. Results: 85.96% (49/57) of knee osteoarthritis (KOA) patients had suprapatellar bursa effusion, 42.1% (24/57) had iliotibial band bursae effusion, some of which had poor sound transmission, and thickened synovium was seen in most effusions, 33.33% (19/57) had osteophyte formation. Compared with before treatment, the depth of suprapatellar sac effusion in the Qi stagnation and blood stasis type group decreased after treatment (P < 0.05). The protrusion height decreased (P < 0.05), and the infrapatellar and prefermoral fat pad thickness increased (P < 0.05). The contrast-enhanced ultrasonography of the thickened synovial membrane of the knee joint in KOA patients showed different degrees of uniform enhancement, showing slow in and slow out. Compared with the surrounding soft tissue, the arterial phase showed equal enhancement. The enhanced synovium had a clear boundary and a clear boundary with the effusion. In the venous phase, the intensity gradually decreased until clearing. Compared with before treatment, there was no significant difference in contrast-enhanced ultrasound parameters in the qi stagnation and blood stasis type group after treatment (P < 0.05). Conclusion: Musculoskeletal contrast-enhanced ultrasonography was used to quantitatively evaluate the efficacy of TCM external therapy on KOA for different TCM constitutions. Dynamic observation of synovial lesions of knee osteoarthritis provides a valuable imaging method for evaluating the efficacy of traditional Chinese medicine.

Wear characteristics of white corundum abrasive wheel in ultrasonic vibration-assisted grinding of AISI 9310 steel

Ultrasonic vibration-assisted grinding has been employed in machining difficult-to-cut materials (e.g. titanium alloys, superalloys, composites, hardened steels, etc.) aiming at improving wear-resistance abilities of abrasive wheels. In this paper, comparative experiments between the conventional grinding (CG) and ultrasonic vibration-assisted grinding (UVAG) were performed on AISI 9310 steel to study grain wear mechanisms. Results shows that UVAG achieves a significant reduction in grinding forces, force ratio and machined quality as material removal volumes raise. Moreover, the wear flat of grains and a sharp change in grinding forces occur. Then, the surface quality gradually deteriorates from the more severe chip clogging of wheels and increasing grinding forces during the CG process. Meanwhile, the steady wear stage of UVAG is longer by 23.07%, and the ground surface roughness in UVAG remain lower and more stably fluctuating than those in CG. Furthermore, UVAG possesses a small fluctuating height of worn grains according to the analysis of the protrusion height distribution at various wear stages, owing to the consistent micro-fractures of the grains under uniform alternating loads. In contrast, pull-out defects can be observed under high grinding forces on the tool–workpiece intersection during the CG process, affecting the ground surface quality.