Transverse Wall Thickness Research Articles

Exploring Intraspecific Trait Variation in a Xerophytic Moss Species Indusiella thianschanica (Ptychomitriaceae) across Environmental Gradients on the Tibetan Plateau.

Investigating intraspecific trait variability is crucial for understanding plant adaptation to various environments, yet research on lithophytic mosses in extreme environments remains scarce. This study focuses on Indusiella thianschanica Broth. Hal., a unique lithophytic moss species in the extreme environments of the Tibetan Plateau, aiming to uncover its adaptation and response mechanisms to environmental changes. Specimens were collected from 26 sites across elevations ranging from 3642 m to 5528 m, and the relationships between 23 morphological traits and 15 environmental factors were analyzed. Results indicated that coefficients of variation (CV) ranged from 5.91% to 36.11%, with gametophyte height (GH) and basal cell transverse wall thickness (STW) showing the highest and lowest variations, respectively. Temperature, elevation, and potential evapo-transpiration (PET) emerged as primary environmental drivers. Leaf traits, especially those of the leaf sheath, exhibited a more pronounced response to the environment. The traits exhibited apparent covariation in response to environmental challenges and indicated flexible adaptive strategies. This study revealed the adaptation and response patterns of different morphological traits of I. thianschanica to environmental changes on the Tibetan Plateau, emphasizing the significant effect of temperature on trait variation. Our findings deepen the understanding of the ecology and adaptive strategies of lithophytic mosses.

Rectal and perirectal CT findings in patients with monkeypox virus infection.

To analyze the findings of proctitis in patients with laboratory-confirmed Mpox and correlate the patient clinical presentation and laboratory findings. 21 patients with PCR-positive Mpox who obtained abdominopelvic CT were retrospectively identified by electronic medical record search. Three radiologists independently evaluated CT images, measuring rectal wall thickness (cm), degree of perirectal fat stranding on a 5-point Likert scale, and size of perirectal lymph nodes (cm, short axis). Mann-Whitney U-test (Wilcoxon rank sum test) was used to assess the association of rectal wall thickness and perirectal fat standing between patients with rectal symptoms and patients without rectal symptoms. 20 of 21 patients presented with perirectal fat stranding, with meanLikert score of 3.0 ± 1.4, indicating moderate perirectal stranding. Mean transverse rectal wall thickness was 1.1 ± 0.5cm (range 0.3-2.3cm); it was thicker among patients with HIV (1.2cm vs 0.7cm; p = .019). Mean perirectal fat stranding was greater among patients presenting with HIV, andwith rectal symptoms, though not significantly so. 17/21 (81%) patients had abnormal mesorectal lymph nodes by at least two of three readers, with mean short-axis measurement 1.0 ± 0.3cm (range 0.5-1.6cm). Multiple linear regression showed no significant correlation between rectal thickness and laboratory values or HIV status. Nearly all patients with Mpox who presented with additional symptoms warranting a CT demonstrated proctitis. Degree of proctitis varied greatly within the cohort, with greatest thickening among patients with HIV. Physicians should have a high suspicion for proctitis in patients with suspected Mpox.

Right ventricular dysfunction during chemotherapy in patients with breast cancer

Aim. To assess the right ventricle (RV) during chemotherapy (CT) in patients with breast cancer (BC).Material and methods. The study included 40 women aged 35-72 years with BC who underwent anthracycline chemotherapy. The main group (n=40) included women with BC, examined at the first contact, 37 of whom were reexamined after 6 months. Control group (n=25) included women without BC.Results. In the main group, the median transverse dimension and anterior wall thickness of the RV were significantly greater than in the control group (p<0,001). Early diastolic transtricuspid flow velocity (Et) after 6 months was lower than in the control group (p=0,003). The ratio of Et to late (At) diastolic transtricuspid flow (Et/At) in BC patients significantly decreased during the follow-up period (p<0,05) when compared with the control group and baseline values. Higher values of Tei index were noted in the main group compared to the control one (p<0,05). Using logistic regression for the Tei index, the model included radiation therapy, the total anthracycline dose, and negative affectivity score as follows: F(3,17)=12,548, p<0,001, R2=0,729. For the Et/At ratio, additional radiation therapy and heart rate were significant factors as follows: F(2,16)=12,548, p=0,005, R2=0,526.Conclusion. Against the background of CT, deterioration of RV systolic (increase in Tei index and RV volume) and diastolic (decrease in Et and Et/At ratio) function was noted.

Shear strength of shear-critical rectangular hollow reinforced concrete columns: Experiments and analysis

Rectangular hollow reinforced concrete (RC) columns have been used extensively for bridge structures. Inadequate transverse confinement and thin wall thickness lead to brittle shear failure, whilst limited studies have reported on the shear model. A hollow high-strength concrete and high-strength stirrups (HHSCS) column, which consisted of high-strength materials, were developed in this paper. The prior monotonic loading tests were conducted to investigate the shear performance on eight specimens. The test variables included aspect ratio, axial compression ratio, and transverse reinforcement ratio. The results revealed that all specimens experienced typical shear failure. On the basis of the modified truss-arch model, a theoretical formula was developed for estimating the shear strength of rectangular hollow RC columns. Also, six existing shear strength models were reviewed and compared with the proposed model using the test data including 37 shear-critical rectangular hollow RC columns. The comparison results showed that the proposed model provided high accuracy of shear strength whether shear-critical rectangular hollow RC columns with high-strength or normal-strength materials.

Acute Appendicitis Associated with CT Intraluminal Hyperattenuation

Introduction: The appendix is identified as blind ending tubular structure arising from caecum and has variable intraluminal contents and position. Acute appendicitis is one of the common indications for emergency imaging studies. Aim: To describe the importance of appendix hyperattenuation and densities. Material and Methods: Contrast enhanced computed tomography images of abdomen from 120 patients with surgically/pathological proven acute appendicitis, were examined retrospectively. The images were reviewed in axial, coronal and sagittal reformations for assessing the intraluminal contents (hyperdensity and appendicolith), maximum transverse diameter and single wall thickness of appendix, periappendiceal fat stranding and other parameters related to acute appendicitis. In addition, reviewing 100 pre- and post-contrast CT scans of other abdominal conditions as a control group for documenting hyperdense appendix, appendicolith and other signs of appendicitis. Results: The hyperdense appendix sign was found in 5 patients in our study, not found in any patient of the control group (P value = 0.039, is statistically), appendicolith was found in 25% in patients with acute appendicitis, in 3% in control group (statistically significant, p < 0.0001). Conclusion: The hyperdense appendix and appendicolith have strong association with acute appendicitis in the appropriate clinical setting.

The Investigation of Pipe Ends Formation under Reduction Mill Rolling

The paper presents the results of the experimental study of the longitudinal and transverse wall thickness variation at the ends of a oil-well tubing during reduction procedure. It is established that the greatest "contribution" to wall thickness data spread is made by the pipe facets, which is caused by the influence of the reduction regimes and the rolls calibration due to the metal flow into the tapers of groove. In the course of work, recommendations were also made that, in order to reduce the wall thickness variation of pipes, it is necessary to develop the calibration ensuring the decreasing of the intensity of metal flow into the tapers of groove, as well as decrease the reduction at the mill stands, and increase the coefficient of kinematic tension between the stands of the stretch-reducing mill.

Supplemental Information to “Method for Improving Transverse Wall Thickness Precision of Seamless Steel Tube Based on Tube Rotation” [J. Iron Steel Res. Int. 22 (2015) No. 10, 924-930

The authors wish to supplement the information for corresponding author. Please see the footnote below. We would like to apologize for any inconvenience caused.

Method for Improving Transverse Wall Thickness Precision of Seamless Steel Tube Based on Tube Rotation

The tube rotation method (TRM) refers to the rotational movement of steel tube about its axis as well as translation in rolling direction in stretch reducing rolling process. The influence of the TRM on transverse wall thickness precision of seamless steel tube was studied. Thickness distribution of the TRM was obtained by superimposing the thickened amount of single pass rolling. Results show that the TRM can effectively improve the evenness of thickness distribution. In order to analyze the influence mechanism of the TRM, the finite element method was adopted to simulate the thickness distribution in stretch reduction process. Results show that the TRM changes the roundtrip flow between two fix places of conventional stretch reducing and inhibits the directional accumulation of metal. In addition, the TRM has a correction effect on thickness cusp. All these advantages of the TRM help to improve the transverse wall thickness precision of seamless steel tube.

50 Mechanical Determinants of Left Ventricular Hypertrophy in Patients with Heart Valve Diseases

Background Increased systolic wall stress has been regarded as the key mechanism by which left ventricular hypertrophy (LVH) develops in pressure or volume overload due to heart valve diseases. However, the variations of LVH have also been well recognised when systolic wall stress does not differ. We have therefore investigated the possible role of myocardial power, the time course of systolic wall stress along with pressure and volume loading status in determining LVH. Methods TOE and LV high fidelity pressures were recorded immediately before heart valve surgery in 109 patients (age 64 ± 12 yr, 73 males). Of whom, 63 were AS, 21 were AR, 25 were MR. Transverse LV cavity dimension and wall thickness were derived from mid-cavity M-mode echocardiograms along with LV pressure by digitising. Thus mean systolic wall stress, peak myocardial power, time from ECG q wave to peak wall stress, LV mass index, LV wall thickness to radius, aortic peak pressure gradient, and MR volume were all determined. Results There is no difference in LV systolic wall stress in 3 valve groups. Aortic valve pressure gradient and MR volume are the key regulator of LV geometry; while LV peak power and duration of stress development positively correlated with LVMI. LV systolic stress is negatively correlated with T/R and LVMI. These were demonstrated by stepwise regression analysis: T/R= 0.84 + 0.0027 AVPG- 0.0040 MR Volume – 0.0016 LV stress, r2=0.72, p Conclusion As expected, pressure or volume overload determines LV geometry. The significant variations of LV mass among heart valve diseases cannot be explained on the basis of systolic wall stress. However, the rate of myocardial energy output (peak power) and the duration of force development (q-peak stress) have played more important role in LVH. LV wall stress appears to be the consequence rather than the cause of LVH. These findings have important implications for our understanding in the mechanism of LV hypertrophy in heart valve diseases.

Explicit FE modelling of tube stretch reduction and analysis of wall thickness variation

In order to minimise transverse wall thickness variation of seamless steel tube produced by stretch reduction, an explicit coupled thermomechanical FE model was established to simulate the stretch reduction process and corresponding experiments were carried out to validate the accuracy of the model. In addition, the plastic flow behaviour of metal in both radial and circumferential directions during forming process was analysed, and the influence of temperature on plastic flow behavior is investigated. Analysis results show that: first, the circumferential flow direction of metal is from roll groove root to roll gap in single pass rolling. Circumferential flowability of metal near the ±30° position of the roll groove shape angle is the most active, and the circumferential flowability of metal near groove root and gap is much weaker. Second, in the entire stretch reduction process, metal flows from positions of roll groove root and gap to the ±30° position of roll groove angle along the circumference. Third, temperature has huge influence on transverse flow behaviour. Metal temperature near the ±30° position of roll groove shape is higher than the temperature of roll groove root and gap. This lowers the deformation resistance of the material so the flowability from roll groove root and gap positions towards the±30° position is strengthened, leading to the transverse wall thickness variation.

Influence of Wall Thickness Fluctuation of Pierced Shell on Continuous Tube Rolling Process of Semi-Floating Mandrel Mill

In continuous tube rolling process, wall thickness reduction per stand will be changed due to wall thickness fluctuation of pierced shell caused by piercing process, which results in changes in metal flow conditions and affects force parameters, deformation parameters, especially transverse wall thickness precision of rolled hollow tube. In this paper, with the aid of commercial FE code MSC.SuperForm, the high pressure boiler steel tube continuous rolling process of a typical hollow tube specification 133.0×4.0mm are simulated based on 133 main pass sequence of 89mm 6-stand semi-floating mandrel mill, and force parameters, equivalent plastic strain, transverse wall thickness precision, outline dimension and real roundness of rolled hollow tube are analyzed and compared on the condition of two different wall thicknesses of pierced shell. Analysis results indicate that force parameters increase with wall thickness of pierced shell, maximal rolling force, rolling moment and mandrel axial force increase 10% or so in the first three stands when rolling pierced shell of wall thickness 11.5mm compared to that of wall thickness 10.5mm. When rolling pierced shell of wall thickness 10.5mm, there exist front and back tensions among the third, the fourth and the fifth stands and outline dimension and real roundness of rolled hollow tube is slightly better. However, transverse wall thickness of rolled hollow tube at the bottom of groove is pulled thin obviously.

Influence of Roll Speed Schedule on Continuous Tube Rolling Process of Semi-Floating Mandrel Mill

In continuous tube rolling process, it has an obvious influence on the stability of rolling process, tools wear and the quality of rolled hollow tube that configuration of roll rotational speed per stand. In this paper, various roll working diameters per stand are determined by velocity integral method (VIT) and FEM respectively, and two roll rotational speed schedules are obtained correspondingly based on 133 main pass sequence of 89mm 6-stand semi-floating mandrel mill. With the aid of commercial FE code MSC.SuperForm, the high pressure boiler steel tube continuous rolling process of a typical hollow tube specification 133.0×5.2mm are simulated, and force parameters, transverse wall thickness precision, outline dimension and real roundness of rolled hollow tube and clearance between the mandrel and rolled hollow tube are analyzed and compared on the condition of two different roll rotational speed schedules, which provides scientific basis for configuring reasonable roll rotational speed per stand in pass design and optimization. Analysis results indicate that roll working diameter obtained per stand is smaller and roll rotational speed configured is higher correspondingly using FEM compared to VIT. Using FEM, there exist front and back tensions between stands and maximal rolling force, rolling moment and mandrel axial force decrease 10% or so in continuous tube rolling process, and outline dimension and real roundness of rolled hollow tube is better. However, transverse wall thickness of rolled hollow tube at the bottom of groove is pulled thin slightly, and clearance between the mandrel and rolled hollow tube is less than normal.

Finite Element Simulation of Cold-Rolling Process of Shaped Steel Tube for Driving Shaft

Based on the deformation characteristics of Y-type mill, a finite element model for simulating the formation process of shaped steel tube for driving shaft is proposed. The distributions of stress and strain were obtained from the simulation. The outer diameter and transverse wall thickness were also analyzed quantitatively. Experiment was done on Y-type mill. A comparison between simulation results and experiment results shows that the simulated results of shaped steel tube are in good agreement with the on-site data. The model could provide the basis for theoretical research and engineering applications of shaped steel tube rolling process.

Research on Design Method of Polygonal Roll Pass for Stretch Reduced Seamless Tubes

the aid of commercially available software MSC.SuperForm, a 3-D finite element model has been established to simulate the rolling process of steel tubes on the stretch reducing mill (SRM) with group centralized differential drive in certain factories. A special effort was made to analyze the fluctuation of transverse wall thickness uniformity. It was found that the wall thickness of each stand was accumulated in the original pass 50°~60° along the circumferential direction, which caused the formation of the inner hexagon defects and worsen. In view of this, this paper proposes a modified roll pass design method which uses the interactive technology of CAD graph curve and MATLAB equation. By means of decreasing the lateral curvature of roll pass contour curve to enlarge the contact length between the tube and groove, also the rolling process using the new pass system were simulated and analyzed. The results indicate that the design of such polygonal roll pass can be effective in improving the inner hexagon defects.

Influence of Roll Speed Schedule on Transverse Wall Thickness Evenness of Shell Elongated by Mandrel Mill

The seamless steel tube continuous rolling process with 8-stand full-floating mandrel is simulated with the aid of commercial FE code MSC. SuperForm. The relationship is analyzed between the distribution of the transverse wall-thickness and the speed schedule of the rollers. The result shows that the transverse evenness of the wall thickness of the tubes can be enhanced by optimizing the speed schedule. Furthermore, by adopting meliorated method to measure the wall-thickness of the shell, the error is reduced while data reliability is increased. When using the existing equipments (mandrel mill), it is an effective way to improve the transverse wall-thickness accuracy of the shell tube by adjusting the speed schedule. Compared with present roll speed schedule, the transverse wall-thickness accuracy can be increased by 10% for the rolling of elongated shell with 152.5mm in OD and 6mm in wall thickness tube under the 3# speed schedule put forward in this paper.

Analysis of Transverse Wall Thickness Precision of Steel Tube Rolled by Semi-Floating Mandrel Mill

With the aid of commercial finite element analysis software MSC. Superform, the high pressure boiler steel tube continuous rolling process with 6-stand semi-floating mandrel is simulated, and the distribution characteristic of transverse wall thickness is analyzed. It indicates that it presents “M” shape that the distribution of transverse wall thickness of hollow tube along one-fourth groove periphery. Transverse wall thicknesses have low values at the top, the bottom and sidewall 45 degree or so of groove, and they have high values at the sidewall 23 degree and 67 degree or so of groove. Then the improved measure is put forward on the basis of analyzing the causes responsible for transverse wall thickness. By the comparison of the simulation results, they have been improved obviously that transverse wall thickness precision and real roundness of rolled hollow tube using the improved measure.

Modified technique of high‐resolution ultrasonography of the normal cervical esophagus

To study a modified technique of neck ultrasound for the visualization of cervical esophagus using a high-resolution and high frequency linear transducer in normal subjects. Consecutive control subjects were patients who underwent abdominal sonography for other diseases and had no past or current history of dysphagia or esophageal disorders. The thyroid gland was used as a transducer window to obtain images. We used a slightly flexed neck position with the head turned 45 degrees to the opposite side while scanning the neck on either side. One-hundred subjects were scanned and their age range was 10-74 years (male:female ratio 1:1). In 36% of cases it was difficult to visualize the right lateral 2/3rd in the traditional scanning position of the neck. This improved to 2% with the modified neck position. All patients had the left window visualized with both neck positions. The transverse diameter, anterior-posterior diameter and wall thickness measures were all significantly greater with the modified technique. All patients tolerated the procedure with no reported discomfort. This modified technique provides superior views of the cervical esophagus, particularly from the right window, in almost all patients. Normal parameters using ultrasound have now been established.

The ultrasonic diagnosis of infantile hypertrophic pyloric stenosis: Technique and accuracy

The role of ultrasound for the diagnosis of pyloric stenosis has yet to be definitely established. We have carried out 147 ultrasound examinations of 142 infants (99 male and 43 female) with a history of projectile vomiting or the possibility of a pyloric mass. Measurements of the pyloric canal length, transverse pyloric diameter and muscle wall thickness were taken from a longitudinal view of the pylorus and related to previously described control data. The accuracy of the ultrasound examination was related to the finally established diagnosis. The results obtained revealed a sensitivity of 97% and specificity of 99% with positive predictive value of 99%. The three diagnostic errors (1 false positive and 2 false negative) occurred during the 'learning curve' of the radiologists and were the 15th, 29th and 35th cases examined, indicating that almost a 100% accuracy can potentially be achieved. This study confirms that ultrasound examination is the first line of investigation in a child in whom the clinical diagnosis of hypertrophic pyloric stenosis is uncertain and indicates that unnecessary surgery can thereby be prevented.

The nondestructive testing of tubes and pipes for nuclear application

The directive of the Reactor Safety Commission demands for all materials which are provided for the pressure bearing enclosure of the refrigerant a nondestructive testing with sufficient sensibility. The specification 3201.1 for nuclear application as well as company-internal rules of important manufacturers regulate the requirements derived from the above direction for the NDT of tubes and pipes. For an objective and reproducible testing, equipments with defined characteristics are employed. based on internal specifications, testing equipments are fabricated and then checked with a special computerized test system. Moreover probes are controlled with regard to their acoustic and electric properties. The NDT of heat exchanger tubes and of pipes is given here as an example: Heat exchanger tubes: The tests include the inspection of longitudinal and transverse defects, wall thickness, dimension and tightness. In connection with the NDT, defect catalogues are set up. By this means the chosen test sensitivity is verified, and so the high quality of the tubes is assured. Specially developed eddy-current methods prove that such tested tubes are free of corrosion-causing phases. Pipes: The pipes are tested for longitudinal and transverse defects, for laminations and for wall thickness. To fulfil the demand for an objective and reproducible testing, there was developed and installed an automatic, computer-controlled ultrasonic equipment with 40 probes. Development trends: For the NDT of heat exchanger and boiler tubes an electrodynamic excited ultrasonic test system is evolved which is also able to test curved and installed tubes. The sophisticated testing technology is completed by a qualified education and training of NDT personnel.

Deep Drilling and Production Practices in the Moore-Hooper Field - Delaware Basin

This paper presents problems and hazards encountered in deep drilling and production in the Moore-Hooperfield of the Delaware Basin. Slow production in the Moore-Hooperfield of the Delaware Basin. Slow penetration rates, high mud costs, and troublesome gas are common. penetration rates, high mud costs, and troublesome gas are common. A detailed discussion presents over-all planning and logic of drilling approach, casing design, mud program, and cementing of deep liners. Introduction Sun Co. drilled the discovery well, Moore-Hooper No. 1, in the Delaware Basin in 1973. Fifteen productive wells have been drilled to date, seven of them by Sun. Twelve are completed and are producing from the prolific Fusselman formation at producing from the prolific Fusselman formation at approximately 19,200 ft. Production from this reservoir is relatively dry gas with 4,000 to 5,000 ppm hydrogen sulfide. Average absolute open flow of these wets is about 160 MMcf/D. Four were also drilled to the Ellenburger formation at 22,000 ft. Production of Ellenburger gas, which contains approximately 50 percent CO2, has been delayed until a gas sales line is available. Plans are for Intratex Gas Co. to start processing this gas Plans are for Intratex Gas Co. to start processing this gas in their Mia Vida field plant in late 1977. Many problems and hazards are involved in deep drilling in this area of the Delaware Basin. This paper highlights some of the major problems such as high mud weights, loss of circulation, controlling kicks and related equipment, and how they were handled. It also presents over-all planning and logic of drilling approach, casing design, mud program, and cementing of deep liners. Included are basic geological data, structure map and cross-section, and brief production history. In early 1976, some 15 rigs capable of 25,000-ft drilling were operating in or within 15 miles of the Moore-Hooper field. This was probably the greatest congregation of super rigs in any concentrated area of the U.S. The Delaware Basin, which extends northwest across Pecos, Ward, Winkler, Loving, and Culberson counties Pecos, Ward, Winkler, Loving, and Culberson counties in Texas, and southern Eddy and Lea counties of New Mexico, long has been recognized as a challenging deep drilling area. The Mentone or Moore-Hooper field area is particularly troublesome because of the very thick, abnormally pressured Lower Wolfcamp, Atoka, and Barnett sections. These formations exceed some 5,900 ft in thickness. Because they are predominately shale with high pore pressures, the result is slower penetration rates, high mud costs, and troublesome gas while drilling. The Moore-Hooper field is a northeast plunging anticline dipping into a fault to the north and northwest. Fig. 1 is a structure map contoured on top of the Fusselman pay. Sun initially drilled the discovery well in Section 79, pay. Sun initially drilled the discovery well in Section 79, then drilled Sections 78, 85, 86, 80, 72, and 89. Subsequent drilling by others, particularly the Clayton William's Gataga No. 2 in Section 81, removed any doubt that the Moore-Hooper and the Vermejo fields are contiguous, forming a sizeable gas field some 8 miles long and 2 to 3 miles in width. Casing and Mud Program Fig. 2 represents a typical casing program that essentially has remained the same. As development drilling progressed, some casing seats were adjusted slightly. Great care was taken to assure that all tubulars were as free from defects as modem testing procedures could determine. Electro-magnetic inspection was performed at the mill, again on the location for longitudinal and transverse defects and wall thickness, and all tubulars were grade verified. JPT P. 1385