Absolute Wall Thickness Measurement of Conducting Plates Using Pulsed Eddy Currents

The method using pulsed eddy currents to determine the thickness of a conduction plate is extended to enable the simultaneous measurement of the plate thickness and material properties. For optimal performance, a probe must be designed depending on the thickness range that should be accessible. The need for a calibration of the material properties of a conducting plate to enable the measurement of its thickness has been removed. All that is needed is a probe with known dimensions and suitable hardware to create a current pulse and measure a transient magnetic induction.

Sonographic gallbladder wall thickness measurement and the prediction of esophageal varices among cirrhotics

Acute variceal bleeding in patients with liver cirrhosis and portal hypertension(PHT) is the most serious emergency complication among those patients and could have catastrophic outcomes if not timely managed. Early screening by esophago-gastro-duodenoscopy(EGD) for the presence of esophageal varices(EVs) is currently recommended by the practice guidelines for all cirrhotic patients. Meanwhile, EGD is not readily accepted or preferred by many patients. The literature is rich in studies to investigate and validate non-invasive markers of EVs prediction aiming at reducing the unneeded endoscopic procedures. Gallbladder(GB) wall thickness(GBWT) measurement has been found promising in many published research articles. We aim to highlight the validity of sonographic GBWT measurement in the prediction of EVs based on the available evidence. We searched databases including Cochrane library, Pub Med, Web of Science and many others for relevant articles. GBWT is associated with the presence of EVs in cirrhotic patients with PHT of different etiologies. The cut-off of GBWT that can predict the presence of EVs varied in the literature and ranges from 3.1 mm to 4.35 mm with variable sensitivities of 46%-90.9% and lower cutoffs in viral cirrhosis compared to non-viral, however GBWT > 4 mm in many studies is associated with acceptable sensitivity up to 90%. Furthermore, a relation was also noticed with the degree of varices and portal hypertensive gastropathy.Among cirrhotics, GBWT > 3.5 mm predicts the presence of advanced(grade Ⅲ-Ⅳ) EVs with a sensitivity of 45%, the sensitivity increased to 92% when a cut-off ≥ 3.95 mm was used in another cohort. Analysis of these results should carefully be revised in the context of ascites, hypoalbuminemia and other intrinsic GB diseases among cirrhotic patients. The sensitivity for prediction of EVs improved upon combining GBWT measurement with other non-invasive predictors, e.g., platelets/GBWT.

Thermal Analysis of Turbine Blades with Thermal Barrier Coatings Using Virtual Wall Thickness Method

Avirtual wall thicknessmethod is developed to simulate the temperature field of turbine bladeswith thermal barrier coatings(TBCs),to simplify the modeling process and improve the calculation efficiency.The results show that the virtualwall thickness method can improve themesh quality by 20%,reduce the number ofmeshes by 76.7%and save the calculation time by 35.5%,compared with the traditional real wall thickness method.The average calculation error of the two methods is between 0.21%and 0.93%.Furthermore,the temperature at the blade leading edge is the highest and the average temperature of the blade pressure surface is higher than that of the suction surface under a certain service condition.The blade surface temperature presents a high temperature at both ends and a low temperature in themiddle height when the temperature of incoming gas is uniformand constant.The thermal insulation effect of TBCs is the worst near the air film hole,and the best at the blade leading edge.According to the calculated temperature field of the substrate-coating system,the highest thermal insulation temperature of the TC layer is 172.01 K,and the thermal insulation proportions of TC,TGO and BC are 93.55%,1.54%and 4.91%,respectively.

Wood anatomy chronologies of Scots pine in the foothills of the Western Sayan(Siberia)

Recent methodological advances in quantitative wood anatomy have provided new insights into the climatic responses of radial growth at the scale of cell structure of tree rings. This study considered long-term chronologies of tracheid measurements, indexed by a novel approach to separate their specific climatic responses from signal recorded in cell production(closely reflected in tree-ring width). To fill gaps in understanding the impact of climate on conifer xylem structure, Scots pine(Pinus sylvestris L.)trees > 200 years old were selected within the forest-steppe zone in southern Siberia. Such habitats undergo mild moisture deficits and the resulting climatic regulation of growth processes. Mean and maximum values of cell radial diameter and cell wall thickness were recorded for each tree ring.Despite a low level of climatogenic stress, components of cell chronologies independent of cambial activity were separated to obtain significant climatic signals revealing the timing of the specific stages of tracheid differentiation. Cell expansion lasted from mid-April to July and was impacted similarly to tree-ring width(stimulated by precipitation and stressed by heat), maximum cell size formed late June. A switch in the climatic responses of mean anatomical traits indicated transition to latewood in mid-July. Secondary wall deposition lasted until mid-September, suppressed by end of season temperatures. Generally, anatomical climatic responses were modulated by a less dry May and September compared with summer months.

Pipeline thickness estimation using the dispersion of higher-order SH guided waves

Thickness measurement plays an important role in the monitoring of pipeline corrosion damage. However, the requirement for prior knowledge of the shear wave velocity in the pipeline material for popular ultrasonic thickness measurement limits its widespread application. This paper proposes a method that utilizes cylindrical shear horizontal(SH) guided waves to estimate pipeline thickness without prior knowledge of shear wave velocity. The inversion formulas are derived from the dispersion of higher-order modes with the high-frequency approximation. The waveform of the example problems is simulated using the real-axis integral method. The data points on the dispersion curves are processed in the frequency domain using the wave-number method. These extracted data are then substituted into the derived formulas. The results verify that employing higher-order SH guided waves for the evaluation of thickness and shear wave velocity yields less than1% error. This method can be applied to both metallic and non-metallic pipelines, thus opening new possibilities for health monitoring of pipeline structures.

Transabdominal intestinal ultrasound and its parameters used in the assessment of pediatric inflammatory bowel disease

This article extends on the use of transabdominal intestinal ultrasound in diagnosing pediatric inflammatory bowel disease.Some of the more essential features used in assessing bowel inflammation,such as hyperemia and wall thickness on ultrasound,are expanded upon from the publication on imaging and endoscopic tools in pediatric inflammatory bowel disease.

Determination of Average Wall Thickness of Mesoporous Silica

Small Angle X-ray Scattering (SAXS) experiment using Synchrotron Radiation as X-ray source was used to determine the average wall thickness of mesoporous silica prepared by condensation of tetraethylorthosilicate (TEOS) using non-ionic alkylpolyethyleneoxide (AEO(9)) surfactant as templates. The results agreed with that of high-resolution TEM (HRTEM) measurement.

Velocity Field and Variation of Wall Thickness During Tube Dieless Upsetting

Theoretical analyses show that the variation of wall thickness is in direct proportion to outer-diameter, inter-diameter, and (1+R_s)^(1/2) (Rs is sectional increase ratio of tube), the theoretical calculated results of wall thickness during tube dieless upsetting are very approximate to the experimental one. As the width of deformation field increases, both the variation of wall thickness and the derivative of wall thickness variation to width of deformation field (to/tf) reduce.

MEASUREMENT OF THE WALL THIOKNESS OF THE TRANSPARENT TUBE BY TOTAL-REFLECTION SHADOW IMAGING

The principle and method for measuring the wall thickness of transparent tube are presented.The measurement is based on total-refection vanishing light. The transmittance of transparent tube in the parallel light is studied. The critical conditions of total--reflection are discussed.

Evaluation of Average Wall Thickness of Organically Modified Mesoporous Silica

The small angle X-ray scattering of organically modified MSU-X silica prepared by co-condensation of tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) show negative deviation from Debye’s theory due to the existence of the organic interface layer. By exerting correction of the scattering negative deviation, Debye relation may be recovered, and the average wall thickness of the material may be evaluated.

Effect of warhead wall thickness on charge uniformity in industrial CT detection

Uniformity of warhead axial charge and influences of different warhead wall thicknesses on measurement results were studied by industrial computed tomography(C T).By comparing the differences of relative density values of the same simulation charge sample assembled in simulation bodies with different wall thicknesses,effects of warhead wall thickness on charge CT relative density values were analyzed.The results show that CT value increases by about1%with the increase of each additional1mm of wall thickness under the same simulation charge for the projectile with outer diameter of100mm and internal diameterof90mm.There fore,to detect uniformity along warhead axial(upper,middle and lower sections)charge density within penetration ability range of industrial CT(IC T),the CT values of various parts(upper,middle and lower sections)may be only measured without measuring absolute density of charge.By subtracting changes in the CT values caused by warhead wall thickness variation,the CT values of various parts under the same charge can describe warhead axial charge uniformity.

Automatic girth welding and performance evaluation of the joints of hot-induction-bend and line pipes with different wall thickness

During the process of laying long-distance oil and gas transmission pipelines, the hot-induction-bend method is extensively used when the direction has to be changed. By considering the pipeline＇ s ongoing processing and loading states during service, the pipeline that is generally used exhibits thicker walls than those that are observed in the line pipe. As such, during pipeline construction, hot-induction-bend and line pipes with different wall thickness are girth-welded. The chemical composition of hot-induction-bend and line pipes differs, with the carbon content being particularly higher in the hot-induction-bend pipe;it also depicts a higher carbon equivalent, which makes it possible to modify the girth of the pipe. In this study, using Baosteel＇ s standard X70M UOE hot- induction-bend and line pipes, solid-wire automatic gas-metal-arc girth welding was performed and the performance of the girth-welded joint was evaluated. Furthermore,the weldability of the pipeline girth and the microstructure of the girth-welded joint were analyzed. The results reveal that Baosteel＇ s standard UOE hot-induction-bend and line pipes exhibit good girth weldability, and their technical quality can be guaranteed in case of consumer field- construction applications.

AXISYMMETRIC PROBLEMS OF CYLINDRICAL SHELLS WITH VARIABLE WALL THICKNESS

The purpose of this paper is to give the general solutions for axisymmetric eylindrical shells with paraholically varying wall thickness.

Simulation Analysis of Torsion Beam Hydroforming Based on the Fluid-Solid Coupling Method

Hydroformed parts are widely used in industrial automotive parts because of their higher stiffness and fatigue strength and reduced weight relative to their corresponding cast and welded parts.This paper reports a hydraulicforming experimental platform for rectangular tube fittings that was constructed to conduct an experiment on the hydraulic forming of rectangular tube fittings.A finite element model was established on the basis of the fluid–solid coupling method and simulation analysis.The correctness of the simulation analysis and the feasibility of the fluid–solid coupling method for hydraulic forming simulation analysis were verified by comparing the experimental results with the simulation results.On the basis of the simulation analysis of the hydraulic process of the torsion beam using the fluid–solid coupling method,a sliding mold suitable for the hydroforming of torsion beams was designed for its structural characteristics.The effects of fluid characteristics,shaping pressure,axial feed rate,and friction coefficient on the wall thicknesses of torsions beams during formation were investigated.Fluid movement speed was related to tube deformation.Shaping pressure had a significant effect on rounded corners and straight edges.The axial feed speed was increased,and the uneven distribution of wall thicknesses was effectively improved.Although the friction coefficient had a nonsignificant effect on the wall thickness of the ladder-shaped region,it had a significant influence on a large deformation of wall thickness in the V-shaped area.In this paper,a method of fluid-solid coupling simulation analysis and sliding die is proposed to study the high pressure forming law in torsion beam.

Prognostic role of intestinal ultrasound in Crohn’s disease

The majority of patients affected by Crohn’s disease(CD)develop a chronic condition with persistent inflammation and relapses that may cause progressive and irreversible damage to the bowel,resulting in stricturing or penetrating complications in around 50%of patients during the natural history of the disease.Surgery is frequently needed to treat complicated disease when pharmacological therapy failes,with a high risk of repeated operations in time.Intestinal ultrasound(IUS),a non-invasive,cost-effective,radiation free and reproducible method for the diagnosis and follow-up of CD,in expert hands,allow a precise assessment of all the disease manifestations:Bowel characteristics,retrodilation,wrapping fat,fistulas and abscesses.Moreover,IUS is able to assess bowel wall thickness,bowel wall stratification(echo-pattern),vascularization and elasticity,as well as mesenteric hypertrophy,lymph-nodes and mesenteric blood flow.Its role in the disease evaluation and behaviour description is well assessed in literature,but less is known about the potential space of IUS as predictor of prognostic factors suggesting response to a medical treatment or postoperative recurrence.The availability of a low cost exam as IUS,able to recognize which patients are more likely to respond to a specific therapy and which patients are at high risk of surgery or complications,could be a very useful instrument in the hands of IBD physician.The aim of this review is to present current evidence about the prognostic role that IUS can show in predicting response to treatment,disease progression,risk of surgery and risk of post-surgical recurrence in CD.

Non-invasive evaluation of lower urinary tract symptoms(LUTS)in men

Lower urinary tract symptoms(LUTS)are common in males over the age of 40 years old and are likely to increase with an aging population.Currently urodynamic studies are the gold standard to determine the aetiology of voiding dysfunction and LUTS.However,due to its invasive nature,a great number of non-invasive ultrasound based investigations have been developed to assess patients with symptomatic LUTS.The clinical application of noninvasive tests could potentially stratify patients who would require more invasive investigations and allow more precise patient directed treatment.A PubMed literature review was performed and we will discuss the non-invasive investigations that have been developed thus far,focusing on bladder wall and detrusor wall thickness(BWT&DWT),ultrasound estimated bladder weight(UEBW)and intravesical prostatic protrusion(IPP).

Collapse-type shrinkage characteristics in plantation-grown eucalypts： I . Correlations of basic density and some structural indices with shrinkage and collapse properties

Collapse-type shrinkage is one of highly refractory drying defects inlow-medium density plantation-grown eucalypt wood used as solid wood products. Basic density (BD),microfibril angle (MFA), double fibre cell wall thickness (DWT), proportion of ray parenchyma (RP),unit cell wall shrinkage, total shrinkage and residual collapse, which are associated withcollapse-type shrinkage characteristics, were investigated by using simple regression method forthree species of collapse-susceptible Eucalyptus urophyll,, E. grandis and E. urophyllaxE.grandis,planted at Dong-Men Forest Farm in Guangxi autonomous region, China. The results indicated that:unit cell wall shrinkage had a extremely strong positive correlation with BD, moderately strongpositive correlation with DWT, and a weakly or moderately negative correlation with RP and MFA;total shrinkage was positively correlated with BD, DWT and RP and negatively related to MFA, but notable to be predicted ideally by any examined factors alone owing to lower R^2 value (R^2≤0.5712);residual collapse was negatively correlated with BD and DWT, linearly positively correlated withMFA, and had strongly positive linear correlation with RP. It is concluded that BD can be used assingle factor (R^2≥ 0.9412) to predicate unit cell wall shrinkage and RP is the relatively soundindicator for predicting residual collapse

Investigation of spherical and concentric mechanism of compound droplets

Polymer shells with high sphericity and uniform wall thickness are always needed in the inertial confined fusion(ICF)experiments.Driven by the need to control the shape of water-in-oil(W1/O)compound droplets,the effects of the density matching level,the interfacial tension and the rotation speed of the continuing fluid field on the sphericity and wall thickness uniformity of the resulting polymer shells were investigated and the spherical and concentric mechanisms were also discussed.The centering of W1/O compound droplets,the location and movement of W1/O compound droplets in the external phase(W2)were significantly affected by the density matching level of the key stage and the rotation speed of the continuing fluid field.Therefore,by optimizing the density matching level and rotation speed,the batch yield of polystyrene(PS)shells with high sphericity and uniform wall thickness increased.Moreover,the sphericity also increased by raising the oil/water(O/W2)interfacial tension,which drove a droplet to be spherical.The experimental results show that the spherical driving force is from the interfacial tension affected by the two relative phases,while the concentric driving force,as a resultant force,is not only affected by the three phases,but also by the continuing fluid field.The understanding of spherical and concentric mechanism can provide some guidance for preparing polymer shells with high sphericity and uniform wall thickness.

Prediction of Mechanical Properties of Structural Bamboo and Its Relationship with Growth Parameters

Bamboo is a renewable natural building material with good mechanical properties.However,due to the heterogeneity and anisotropy of bamboo stalk,a large amount of material performance testing costs are required in engineering applications.In this work,longitudinal compression,bending,longitudinal shear,longitudinal tensile,transverse compression and transverse tensile tests of bamboo materials are conducted,considering the influence of the bamboo nodes.The mechanical properties of the whole bamboo stalk with the wall thickness and outer circumference are explored.Through univariate and multiple regression analysis,the relationship between mechanical properties and wall thickness and perimeter is fitted,and the conversion parameters between different mechanical properties are derived.The research results show that the transverse compressive strength of nodal specimen,and transverse tensile strength of nodal and inter-node specimens increase with the increase of wall thickness and outer circumference,but other mechanical properties decrease with the increase of wall thickness and outer circumference.The prediction formula and conversion parameters of bamboo mechanical properties proposed in this research have high applicability and accuracy.Moreover,this research can provide references for the evaluation of bamboo performance and saving test costs.

Inverse problem of pulsed eddy current field of ferromagnetic plates

To determine the wall thickness, conductivity and permeability of a ferromagnetic plate, an inverse problem is established with measured values and calculated values of time-domain induced voltage in pulsed eddy current testing on the plate. From time-domain analytical expressions of the partial derivatives of induced voltage with respect to parameters,it is deduced that the partial derivatives are approximately linearly dependent. Then the constraints of these parameters are obtained by solving a partial linear differential equation. It is indicated that only the product of conductivity and wall thickness, and the product of relative permeability and wall thickness can be determined accurately through the inverse problem with time-domain induced voltage. In the practical testing, supposing the conductivity of the ferromagnetic plate under test is a fixed value, and then the relative variation of wall thickness between two testing points can be calculated via the ratio of the corresponding inversion results of the product of conductivity and wall thickness. Finally, this method for wall thickness measurement is verified by the experiment results of a carbon steel plate.