End Hole Research Articles

In vivo Imaging and Pharmacokinetics of Percutaneously Injected Ultrasound and X-ray Imageable Thermosensitive Hydrogel loaded with Doxorubicin versus Free Drug in Swine.

Intratumoral injections often lack visibility, leading to unpredictable outcomes such as incomplete tumor coverage, off-target drug delivery and systemic toxicities. This study investigated an ultrasound (US) and x-ray imageable thermosensitive hydrogel based on poloxamer 407 (POL) percutaneously delivered in a healthy swine model. The primary objective was to assess the 2D and 3D distribution of the hydrogel within tissue across three different needle devices and injection sites: liver, kidney, and intercostal muscle region. Secondly, pharmacokinetics of POL loaded with doxorubicin (POLDOX) were evaluated and compared to free doxorubicin injection (DOXSoln) with a Single End Hole Needle. Utilizing 2D and 3D morphometrics from US and x-ray imaging techniques such as Computed Tomography (CT) and Cone Beam CT (CBCT), we monitored the localization and leakage of POLDOX over time. Relative iodine concentrations measured with CBCT following incorporation of an iodinated contrast agent in POL indicated potential drug diffusion and advection transport. Furthermore, US imaging revealed temporal changes, suggesting variations in acoustic intensity, heterogeneity, and echotextures. Notably, 3D reconstruction of the distribution of POL and POLDOX from 2D ultrasound frames was achieved and morphometric data obtained. Pharmacokinetic analysis revealed lower systemic exposure of the drug in various organs with POLDOX formulation compared to DOXSoln formulation. This was demonstrated by a lower area under the curve (852.1 ± 409.1 ng/mL·h vs 2283.4 ± 377.2 ng/mL·h) in the plasma profile, suggesting a potential reduction in systemic toxicity. Overall, the use of POL formulation offers a promising strategy for precise and localized drug delivery, that may minimize adverse effects. Dual modality POL imaging enabled analysis of patterns of gel distribution and morphology, alongside of pharmacokinetics of local delivery. Incorporating hydrogels into drug delivery systems holds significant promise for improving the predictability of the delivered drug and enhancing spatial conformability. These advancements can potentially enhance the safety and precision of anticancer therapy.

Pressure Relief Gas Drainage in a Fully Mechanised Mining Face Based on the Comprehensive Determination of ‘Three Zones’ Development Height

The gas emission from the goaf generates gas in the upper corner of the working face, and the return airflow exceeds safe limits. The identification of the reasonable level of the high-long borehole is the key factor to ensure the effectiveness of its extraction. On-site test at the 2308 working face of Licun Coal Industry of Lu’an Chemical Industry Group, the development of coal overlying strata fracture was studied through derivation of theoretical and empirical formulae, physical similarity experiment, and UDEC numerical simulation: this was then combined with in-situ microseismic monitoring to obtain the distribution characteristics of mining overburden “falling zone” and “overbreak zone” under the actual working conditions, and accurately design the high-level long borehole end hole layer. The results show that the height of the falling zone is 17.5 m to 20.5 m, and the overbreak zone is 43.5 m to 49.5 m. When the hole position is between 25 m and 30 m in the middle and lower part of the overbreak zone, the flow and concentration of gas extracted by drilling are high, and the pure amount of gas extracted by a single hole is increased by 53% (on average). The investigation of pressure relief gas extraction shows that throughout the mining period, the average gas concentration in the return airway is maintained below 0.36%, and the average gas concentration in the upper corner is kept within 0.48% (effective gas control). The research proves the rationality of the arrangement of the high-level long borehole horizon in the working face and provides a reference for the design of the borehole horizon in the future gas drainage and control in the goaf.

Pulmonary Artery Wedge Pressure Can Underestimate Direct Pulmonary Vein Pressure in Pediatric Pulmonary Vein Stenosis

BackgroundPulmonary artery wedge pressure (PAWP) can underestimate directly measured pulmonary vein pressure (PVP) as demonstrated in animal studies and human case reports. This concept has not been validated in a larger cohort of pediatric patients with pulmonary vein stenosis (PVS). MethodsPediatric patients who underwent cardiac catheterization for PVS at a single center from January 1, 2018, to March 31, 2023, were retrospectively reviewed. Mismatch between the PAWP and directly measured PVP or LA pressure was defined as >3 mm Hg. Preintervention angiography was reviewed and percent stenosis calculated. ResultsTwenty-six patients met inclusion criteria; 51 lower pulmonary veins (34 left, 17 right) from 42 catheterizations were evaluated. Significant PVS (≥30% stenosis) was seen in 38/51 (75%) veins, and 9/51 (18%) veins had no angiographic narrowing (0% stenosis). PAWP-PVP mismatch occurred in 37/51 (73%) veins with a median difference of 8 mm Hg (IQR, 6-12). Of these, PAWP was equal to LA pressure in 26 instances, all of which had significant PVS (median % stenosis 54 [IQR, 45-60]). Six of the cases with PAWP-PVP mismatch, PVS (range, 41%-70% stenosis), and no PAWP-LA mismatch reported both a proximal and distal segmental PAWP. In all 6 instances, there was no distal PAWP-PVP mismatch (median difference 1 mm Hg [range, 0-3]). ConclusionsIn this single-center study of pediatric patients with PVS, PAWP significantly underestimated directly measured PVP in lower pulmonary veins. Balloon wedge or end hole catheter position in a distal lobar segment may more accurately estimate the PVP.

Mechanical analysis of new-type arc-cone anchor for CFRP strand wires

Conventional anchors tend to produce ‘notch-effect’ at the tensile end due to stress concentration when anchoring prestressed CFRP strand cables. A new-type arc-cone anchor was designed with the purpose of optimizing the stress distribution in the anchor zone in this study. The ‘arc-cone’ model was proposed to represent the mechanical characteristics of the anchor, and the numerical simulation and experiments were carried out. The effect of the design factors on the anchoring performance was discussed, involving the arc-cone radius, the anchoring length, and the end hole wall thickness. The failure mode, the ultimate load, the anchoring efficiency coefficient as well as the stress distribution were ascertained with the consideration of the effect of the abovementioned design factors. The research results show that the extrusion stress on the barrel decreases with respect to both the wall thickness and the anchor length. The larger the radius of the arc-cone is, the larger the slip of the CFRP strand wire is. The proposed anchor configuration inversely changes the stress distribution from the tensile end to the free end, alleviates the ‘notch effect’ existing in the anchoring zone of conventional anchors, and consequently, improves the anchoring efficiency for CFRP strand wires.

A new method to establish coupled multi-physics model of lubricated pin-hole oscillating pair

Under severe working conditions, about 10 % of the total engine friction loss originates from the piston pin-hole oscillating pair, significantly impacting the engine's reliability. Nevertheless, a systematic analysis encompassing the multi-physics environment (including lubrication, dynamics, and heat transfer) and their coupled behaviors is still lacking. A new coupled modeling method is proposed to achieve this, which can account for thermal deformation and frictional heat generation. All key components in this study are represented as three-dimensional flexible bodies, enabling a thorough characterization of the intricate secondary motions influencing lubrication. The method is applied to a lubricated oscillating pair test system, and a 1:1 simulation model is established. Experimental results also affirm its high accuracy. The model calculation results demonstrate that thermal deformation constrains pin secondary motions and increases axial load inhomogeneity. After factoring in fluid and asperity friction heat, the average friction coefficients at the small end hole (SEH) and pin base hole (PBH) increase by 1.8 % and 11.3 %, respectively. Furthermore, a parametric analysis is conducted, and the instantaneous friction coefficient curves under different loads/temperatures/frequencies are given. These findings can offer valuable insights into the tribological design of oscillating pairs.

Design of Brush Plating Repair Device for Big Hole of Connecting Rod of Automobile

Brush plating technology has been applied to the surface repair and strengthening of parts and achieved remarkable benefits, so it can be used as a part remanufacturing method. This graduation project aims to design a brush plating repair device for the big end hole of an automobile connecting rod in the field of automobile technology application, including brush plating power supply, electroplating pen, plating solution, and brush plating auxiliary equipment, so as to realize the clamping and rotation of the workpiece, the clamping of plating pen and the axial and radial movement of plating pen relative to the workpiece. The three-dimensional models of parts and parts are established by modeling software and installed. The equipment can greatly improve the maintenance efficiency and product quality of vehicle connecting rods, obtain a safer production process, and is suitable for mass reproduction of vehicle connecting rods.

Проектирование параметрических циклов фрезерования отверстий на станках с ЧПУ

The paper describes the stages of designing the technological end hole milling cycle and presents the developed CONICALINT software, which generates a G-code with argument lists used to call up a technological cycle from the CNC system memory. The developed algorithm for the technological end hole milling cycle has a branched structure, since it can choose between two methods for calculating the internal cycle parameters and two milling methods – climb down and climb up. The calculation of the internal technological cycle parameters consists of calculating the coordinates of the points necessary to construct the helical path of the cutting tool, as well as the maximum permissible value of the helical pitch within a given set of input parameters. The initial calculation data are represented by thirteen parameters characterizing the geometry of the cutting tool, the geometry of the required machined surface, as well as the parameters that determine the milling method and the method for calculating the cutting mode and the starting points of the cutting tool path. We identified eight boundary conditions that determine the permissible values of the input parameters. Based on these conditions, we designed a system of inequalities with a set of error messages displayed to the user if any of the input parameters is entered incorrectly. The developed Gcode of the technological cycle subprogram for a CNC machine calculates the tool movement both along a helical and a conical helical path, depending on the input parameters, which allows using it to program cylindrical and conical hole milling. The developed CONICALINT software is a visual addition to the developed technological cycle of hole milling. The developed CONICALINT software is a visual addition to the developed technological hole milling cycle, which allows generating a control G-code with a set of twelve arguments.

Creep‐fatigue behavior of thin‐walled plate with holes: Stress state characterization and life estimation

AbstractThis paper proposes a novel creep‐fatigue life estimation method considering the effect of non‐uniform stress state, through the comprehensively experimental and numerical investigation. Conventional and digital image correlation (DIC) based in‐situ creep‐fatigue tests were performed on thin‐walled plates with various types of holes at 850°C. DIC measurements and scanning electron microscope (SEM) analysis show that tensile stress plays the dominant role in the creep‐fatigue failure of plate with holes, and the crack initiated at the maximum stress position of the end hole. An equivalent stress was defined to describe the complex stress state between the adjacent holes. The stress factor was proposed to account for the holes‐related stress concentration and multi‐axial stress state. Moreover, a novel weight function was proposed to assess the damage contribution of non‐uniform stress in the damage zone. Creep‐fatigue life model was developed by introducing this proposed weight function, and was validated based on test data.

The method to remove parts from the multi-step oil well centrifugal pump housing on a workbench

Repair of centrifugal oil pumps requires their total tear-down, with removal of steel parts from the cylindrical housing made of thick-walled steel tubes. This paper describes the technology of removal of steel parts from the tube using an air-driven hammer with a piston of relatively small weight of 40 kg. The complete tear-down of the deep-well centrifugal pump is implemented using a facility with a guiding frame. The frame accommodates the mutually appressed air-driven hammer, a nozzle with a conical seating surface, a tube section with a side window and a stepped flange adaptor. The latter is pressed to the end face of the pump housing. The other end of the housing is butted on the energy sink fastened on the guiding frame. The described facility has a rod passed through the open end hole in the energy sink and along the opening of the housing, which interacts with the parts in the housing via one end and with the drive via the other end.

MO787: Effects of the End Structure of Temporary Indwelling Catheters on Blood Recirculation under Varying Blood Flow Rates of a Dialysis Machine and Diameters of a Mock Blood Vessel

Abstract BACKGROUND AND AIMS The performance of temporary indwelling catheters allowing higher recirculation during hemodialysis may result in reduced clearance and inadequate dialysis and consequently, reduced patient survival. In actual clinical practice, it is often necessary to use a reverse connection to recover the blood flow rate for dialysis when there is inadequate blood removal during the treatment. The aim of the present study was to determine the effects of the end-structure of catheters used for hemodialysis on blood recirculation under varying blood flow rates of a dialysis machine and diameters of a mock blood vessel in a well-defined in vitro experimental system, focusing on the reverse connection. METHOD Pig blood was circulated by a roller pump through a mock vessel made of silicon tubes with an inner diameter of 15 mm or 20 mm. The tip of the inserted catheter was fixed at the center of a silicone tube. We connected the catheter to a dialysis machine, a blood circuit and a dialyzer. The blood flow rate of the dialysis machine was set at 100, 150, or 200 mL/min and the recirculation rates were determined. The recirculation rate was measured three times under each condition, and the average value was determined. Five types of catheters were used; Argyle TM 12 Fr × 25 cm (catheter A), Gentle Cath TM (Hardness gradient type) 12 Fr × 13 cm (catheter B), Gentle Cath TM 12 Fr × 24 cm (catheter C), Niagara TM 13.5 Fr × 24 cm (catheter D), Power-Trialysis® 13 Fr × 24 cm (catheter E). Catheters A, B, C and D have asymmetric structures with a side hole, while E has a symmetric structure. RESULTS The recirculation in the sequential connection was very low for all catheters. The recirculation rates in the reverse connection for catheters A, B, C, D and E were 40%, 25%, 17%, 25% and 10%, respectively. The recirculation rates were the lowest when the blood flow rate of the dialysis machine was set at 200 mL/min and the inner diameter of the mock blood vessel was 20 mm. DISCUSSION Recirculation was most likely to occur for catheter A. The distance from the end hole to the side hole was longer in catheters B, C and D than in catheter A, which could explain the lower recirculation rates. Among the catheters, catheter C had the largest side hole, and the blood spread widely into the vessel, leading to a lower recirculation rate. Therefore, the distance between the end hole and the side hole and the size of the end hole was deduced as being essential factors for reducing the recirculation in the case of reverse connection. For catheter E, the blood flow line in the mock vessel coming from the dialysis machine through the blood returning hole (side hole) was helical, and little blood existed near the blood withdrawal hole (the other side hole), which could be responsible for the reduced recirculation rate. CONCLUSION The least recirculation in the reverse connection was observed with symmetrical catheters, where the blood streamlines were spiral and did not intersect with the blood streamline between the blood withdrawal hole and the blood returning hole.

An analytical stress field for bi-material V-notches with end hole: New solution and effects of higher order terms

Current manuscript develops an analytical stress solution for the bi-material V-notches with an end hole (VO). To do so, based on the Kolosov-Muskhelishvili’s approach, while appropriate potential functions are employed, the boundary conditions of the problem are imposed to the solution to reduce the number of unknown parameters. Subsequently, the analytical stress field is derived as an asymptotic series solution, where each term possessing a constant coefficient and an order of singularity. The order of singularity for each term is obtained from the characteristic equations of the problem which is dependent on the notch geometry and material combinations. The so-called least square method (LSM) is then used to compute the constant coefficients of the asymptotic series for several case studies. Special attention is given to the bi-material notch stress intensity factors (BNSIFs) and the coefficients of the higher order terms (HOTs) in the stress series expansion. The accuracy of the presented stress solution is verified by benchmarking the results with numerical values obtained from finite element (FE) method. In this process, several notch opening angles and notch radii are simulated using the three-point bend (3PB) specimen. The developed asymptotic stress solution is demonstrated to be capable of accurately evaluating the stress field around bi-material VO-notched structures.

Abstract 13023: Contemporary Echocardiography-Guided Pericardiocentesis Outcomes in a High-Volume Tertiary Teaching Hospital

Introduction: First performed in the 1970s, echo-guided pericardiocentesis has become the preferred approach for draining pericardial effusions. After identifying the largest pocket, a cardiology attending and fellow use a micropuncture needle kit, confirm placement with agitated saline, and leave a side and end hole 8 French drain stocked with sterile saline. This is drained every 8 hours by nursing and never left to gravity or else it tends to clot. The drain is removed when output is <25 cc in 24 hours, or by 7 days. Methods: We prospectively maintained an IRB approved database of pericardiocenteses performed by three experienced cardiology attendings directly supervising a multitude of fellows between 2009-2021 at Thomas Jefferson University Hospital. Results: Of 391 pericardiocenteses, 61% were for tamponade. 66% were done from an apical approach, 18% subcostal, 11% left parasternal, and 2% right parasternal. Drains were left in for an average of 3.1 days (range 1-10 days). An average of 578 mL were drained with the initial procedure (range 5-2670 mL), and 62% of effusions were bloody. A total of 42% were deemed idiopathic, without an identifiable cause, 27% were associated with malignancy (56% of these had positive cytology with remaining unlikely from any other cause), 9% after open heart surgery (valve replacement, heart transplant, dissection repair), 8% post-procedural (electrophysiology, cardiac catheterization, line placement), 5% were in chronic dialysis patients, and the remainder were due to a combination of hemorrhage not related to a procedure, rheumatic, post-radiation, or medication-induced. The rate of serious complications was 3% and included 4 pneumothoraces, 3 hemothoraces, 3 cases of pericardial decompression syndrome, 1 RV microperforation, and one PEA arrest resulting from cardiac perforation. There were no mortalities. The rate of non-serious complications was 4% and included pleural placement of drain in 8, severe pain remitting with drain removal in 5, prolonged bleeding from puncture site in 2, and SVT during placement in 1. Conclusion: Overall, echocardiography-guided pericardiocentesis by experienced providers supervising fellows-in-training is a safe and effective means of draining pericardial effusions.

Расчет акустической эффективности глушителей шума выпуска автотранспортных двигателей внутреннего сгорания

Insertion losses as the main characteristic that mathematically describes the acoustic efficiency of a noise silencer has been considered. This characteristic shows the reduction of noise generated by its source, in particular by the internal combustion engine’s exhaust system, at the control point as a silencer use result. Has been presented a mathematical description of the insertion losses, and have been considered parameters necessary for calculating this characteristic. Has been demonstrated the analytical dependence of impedance for the sound emission by the exhaust system’s end hole from the coefficient of acoustic waves reflection by this hole. The performed analysis of the widely used formulas for calculating the coefficient of sound reflection by the end hole has showed their insufficient accuracy for project designs performing. Have been proposed calculation dependences providing high accuracy for calculations of the reflection coefficient modulus, and the attached length of the channel end hole without a flange in the entire range of the existence of plane waves in it. It has been shown that the end correction of this hole at ka = 0 is 0.6127, and not 0.6133, as it was mistakenly believed until now in world acoustics. Has been proposed a method for calculation the exhaust noise source internal impedance. This method more accurately, in comparison with the already known ones, describes the acoustic processes in the internal combustion engine’s exhaust manifold, thanks to increases the accuracy of calculation the silencer acoustic efficiency, that allows develop the silencer at the early stages of the design of an automotive internal combustion engine.

Investigation the fracture behavior of high-density polyethylene PE80 weakened by inclined U-notch with end hole

In this article, the Strain Energy Density (SED) averaged over a well-defined control volume at a notch edge was applied in combination with the Equivalent Material Concept (EMC) to assess the fracture behaviors of some keyhole-notched specimens made of a High-Density Polyethylene (HDPE-PE80) material under mixed-mode loading conditions. An experimental program was performed and 54 new experimental data were totally provided. Additionally, different loading mode ratios were regarded by changing the inclination angles of the notches with respect to the applied load directions. The results obtained from the determined criteria were in good agreement with those of the experimental data.

Enhancement of Gas Discharge from a Closed End Hole by Using Acoustic Wave Irradiation

Filling holes with liquid, or discharging gas from holes, is a fundamental process in both cleaning and painting. Discharging gas from small holes with closed end and high aspect ratio is extremely difficult due to surface tension. In this study, we developed a new gas discharge process from a hole by using acoustic wave irradiation. We irradiated two types of acoustic waves: waves with constant frequencies and those with variable frequencies in time i.e. sweep wave for test samples in a water pool. In addition, we observed gas discharge using high-speed video camera. As a result, we succeeded in completely discharging gas by using sweep frequency of the acoustic waves. From the observation results, we confirmed that gas discharge consists of three stages. The gas was discharged from the hole mainly at the first and third stage. In these stages, the natural frequency of the gas column in the hole was essential. In the second stage, the gas column in the hole breaks into multiple gas columns; then, the gas was hardly discharged even with the acoustic wave irradiation.

3:09 PM Abstract No. 63 Balloon occlusion embolization in prostate artery embolization: a single-center evaluation of procedural metrics and clinical outcomes

Prostate artery embolization (PAE) is a technically challenging procedure with significant anatomical variation and collateral vessels to surrounding organs. Balloon occlusion (BO) has been proposed as a technique to reduce reflux-mediated nontarget embolization and deliver more embolic particles than would be possible without flow reversal in distal collateral vessels. There has been very limited study of BO in PAE. This study assesses how BO affects technical aspects of PAE and clinical outcomes. 73 patients who underwent PAE from June 2014 to August 2019 were retrospectively reviewed. Bilateral PAE was performed in 17 patients with BO microcatheters and 56 patients with end-hole (EH) microcatheters. Embolization was performed with microspheres ranging from 100 to 300 μm (Embozene, Embospheres) prepared with a 2-mL vial of particles in 15- or 20-mL dilution for the majority of patients. The decision to use BO was based on prostate artery anatomy. Total embolic volume delivered, dose area product (DAP), fluoro time (FT), contrast volume, collateral vessels coiled, International prostate severity score (IPSS), quality of life (QOL), and adverse events (AE) were recorded. For the EH group, mean embolic delivered: 0.78 mL, mean DAP: 651 Gy-cm2, mean FT: 38.5 min, mean contrast used: 135 mL and 9/56 (16%) had collateral vessels coiled. For the BO group, mean embolic delivered: 0.97 mL (P = 0.02), mean DAP: 448 Gy-cm2 (P = NS), mean FT: 28.6 min (P = 0.01), mean contrast used: 112 mL (P = NS), and 3/17 (18%) patients had collateral vessels coiled (P = NS). Over a mean follow-up of 6 weeks, mean IPSS improved from 20.1 to 9.6 (↓52%) and QOL improved from 4.3 to 1.9 (↓56%) in the EH group. In the BO group, mean IPSS improved from 19.1 to 10.2 (↓47%, P = NS) and QOL improved from 3.9 to 1.9 (↓51%, P = NS). No AEs occurred in the BO group. In the EH group, 3 AEs occurred (2 hematuria, 1 penile ulcer). Use of BO microcatheters is safe and associated with lower FT and increased embolic delivery. However, there is no difference in protective coiling rate or short-term clinical outcomes. Further study is warranted with longer follow-up and assessment of the effects of increased embolic delivery using BO.

Comparative analysis of the fracture splitting deformation of the big end for C70S6, 36MnVS4 and 46MnVS5 connecting rods

During the fracture splitting process of the connecting rod, the plastic deformation, especially the plastic deformation before cracking, not only causes the big end hole of the connecting rod to be out of roundness, but also increases the residual stress, affecting the assembly precision and even the service life of the connecting rod. In this paper, the mechanical properties of microalloyed steel C70S6, 36MnVS4 and 46MnVS5 connecting rod were determined by tensile test. The displacement field, plastic strain and the deformation principle of the big end before the crack initiation of the fracture splitting of the connecting rod were numerically simulated. The results show that the yield strength, tensile strength and plasticity index of the new medium carbon microalloyed steels 46MnVS5 and 36MnVS4 are significantly higher than those of C70S6. However, the C70S6 connecting rod has a long loading time before crack initiation, and the plastic deformation area of the groove root front is large and the strain is high. The plastic deformation of 36MnVS4 and 46MnVS5 connecting rods is small and the area is concentrated. Among the three, the 46MnVS5 connecting rod has the smallest deformation and the C70S6 connecting rod has the largest deformation.

Optical inspection device for the inner surface of pipe ends

The inner surface of the holes in the ends of tubing pipes used in oil production is most prone to deterioration. The mechanical loads combined with corrosion lead to the formation of pits on the surface of the holes. A tubing burst leads to significant financial, technological and environmental losses. The existing methods of non-destructive inspection do not allow to measure the depth of a corrosion pit (cavity) on the surface of the pipe end hole. We propose the construction of the device for monitoring the pipe inner surface closely adjacent to its end. The device uses the optical principle of monitoring the presence and the depth of corrosion pits on the surface of the tubing pipe end hole. The device uses structured lighting of the ring of the hole surface. Judging by the out-of-roundness of the light-shadow border, we evaluated the depth of the defects on the hole surface. The device was tested and calibrated on a special stand, where the depth of the cavity was changed with a step of 30 microns. The reflected light flow from the target surface was recorded by a video camera. Tests of the device showed its resistance to the disturbances in the form of stray lighting, electromagnetic interference, vibrations and dirt in the room (no special operating conditions are required). The length of the corrosion pit does not affect the sensitivity of the device. If the material of the controlled tubing changes, the device shall be calibrated. For a 4 mm long defect, the depth of the corrosion pit up to 1.5 mm can be detected. Preliminary calibration of the device allows to reduce the measurement errors caused by the technological and operational reasons. The developed device is able to detect the presence of a corrosion pit on the hole surface. The accuracy of measuring the depth of the defect on the pipe surface is not less than 150 microns, which is acceptable for oil pipe repair plants. The device can be operated manually and can be built into an automated control system. The monitoring results can be documented. The developed device can be used in other areas: inspection of holes made in reinforced concrete structures, inspection of surface of the holes of chemical production pipes, GTE fuel system, etc.

Study on the mechanisms and prevention of water inrush events in a deeply buried high-pressure coal seam—a case study of the Chensilou Coal Mine in China

Coal mine formations are becoming increasingly threatened by water inrush accidents resulting from high-pressure water conditions in limestone formations below mines with increasingly greater mining depths. This paper focuses on the floor of a deeply buried coal seam and the high-pressure fully mechanized mining faces of the Chensilou Coal Mine in China. Based on systematic observations and analysis of the geological and hydrogeological conditions in the study area, this study conducts theoretical analyses, numerical simulations, and underground observations in a comprehensive manner. Accordingly, a systematic and substantive investigation of the deformation and failure of the deep mining floor and the water inrush mechanism (i.e., the high hydraulic pressure within ash-filled fissures) in the Chensilou Coal Mine is carried out. The burial depth is deeper than 761.4 m, and the water pressure in the limestone of the Taiyuan Formation exceeds 4.95 MPa. Furthermore, the mining depth of the working face is 34.25 m. Based on data on water inrush events and subsurface mining failure depth, the water inrush mechanism in the floor of the coal seam in the Taiyuan Formation is analyzed. The end hole depth of the working face is composed of the L8 limestone, and transient electromagnetic detection technology is used to test the grouting effect of the working face floor and ensure the mining safety of the three working faces tested in this study.

Case-Control Comparison of Conventional End-Hole versus Balloon-Occlusion Microcatheter Prostatic Artery Embolization for Treatment of Symptomatic Benign Prostatic Hyperplasia.

To compare procedural metrics and clinical improvement for prostatic artery embolization (PAE) performed with a balloon-occlusion (BO) versus end-hole (EH) microcatheter in patients with benign prostatic hyperplasia. Retrospective review was performed of 129 patients undergoing PAE with 100-300 μm Embosphere microspheres from April 2013 through August 2018. Microcatheter selection was nonrandom, based on prostatic artery anatomy. Five technical failures and 5 microcatheter crossover cases were excluded. BO group (n= 46, age 72.8 y ± 9.0, gland volume 184 mL ± 83, 42% in retention) and EH group (n= 73, age 76.0 y ± 9.0, gland volume 190 mL ± 116, 44% in retention) were compared using procedural metrics (excluding 30 EH learning-curve cases); symptomatic improvement at 3, 6, and 12 months after PAE; voiding trial success; and adverse events (reported used Clavien-Dindo classification). Procedural and fluoroscopy times were lower in the BO group (n= 46) vs EH group (n= 43) (152.0 min ± 34.0 vs 172.8 min ± 47.9, P < .02; 37.8 min ± 12.9 vs 50.3 min ± 18.9, P < .001). Collaterals coiled, contrast material used, and injected particle volume were similar for both groups (P= NS). International Prostate Symptom Score improvement was similar for BO group (n= 25) (before PAE 23.5 ± 6.5, 12 months after PAE 7.6 ± 6.8) and EH group (n= 30) (before PAE 20.9 ± 5.9, 12 months after PAE 6.6 ± 5.2) (P= NS). Quality-of-life improvements were also similar (BO: before PAE 4.5 ± 1.2, 12 months after PAE 1.4 ± 0.9; EH: before PAE 4.1 ± 1.0, 12 months after PAE 0.9 ± 0.7), as were 12-month postvoid residual improvements, voiding trial failure rates (EH 12%, BO 8%), and adverse event rates (grade II, III: EH 15%, BO 11%) (P= NS for all). BO microcatheter use in PAE did not affect injected particle volume, contrast material use, or protective coiling and did not impact symptomatic improvement, postvoid residual improvement, voiding trial success, or adverse events after PAE. Lower procedure and fluoroscopy times with BO microcatheter were likely due to selection bias.