Stainless Steel Plug Research Articles

Direct measurement and calculation of rubber bulk modulus by piston-cylinder method using conventional mechanical testing equipment

This article describes a method to directly measure the bulk modulus of rubber using a piston-cylinder type apparatus. The function of the testing apparatus is to reliably transfer load to the water inside the vessel and allow for the accurate and continuous measurement of volumetric displacement as the contents are compressed. During the test, load is applied to a piston-cylinder containing the rubber test sample and water using a conventional mechanical testing load frame. Load and the travel of the piston are recorded by a load cell and extensometer, respectfully. A brass or stainless steel plug of the same dimensions as the test sample is tested as a control sample to isolate the compliance of the system, including the compressibility of water and compliance of the o-rings which seal the piston-cylinder system. The results from this control test are used to decouple the compliance of the system from the sample test results. Load-linear displacement data are mathematically converted to pressure-volumetric displacement data, from which bulk modulus is calculated. The test apparatus and method are validated using the known bulk modulus of water. Finally, the bulk moduli for two similar rubbers are evaluated. The validity of the results and limitations of the device are discussed.

Abstract No. 492 Comparison of complication rates associated with Celt and Angio-Seal vascular closure devices: a single-center retrospective review

Celt and Angio-Seal are prominent vascular closure devices (VCD) used for achieving hemostasis at the access site after endovascular procedures. The Celt uses a stainless-steel plug and the Angio-Seal uses a collagen-based plug. Complications of VCD placement include pseudoaneurysm, arteriovenous fistula formation, hematoma, and limb ischemia. To date, there is a paucity of published studies comparing the safety of these devices in interventional radiology (IR). We investigated the rates of complications between Celt and Angio-Seal in patients within interventional radiology.

Microstructure and mechanical properties of underwater friction taper plug weld on X65 steel with carbon and stainless steel plugs

Underwater friction taper plug welding for X65 pipeline steel was performed using Q345 structural steel and 316L stainless steel plugs. Weld microstructures, defects formation and mechanical properties were investigated. Using Q345 plugs can produce defect free and overmatching welded joints whose impact toughness was also favourable. Lower bainite and lath martensite in the weld zone resulted in high hardness with maximum value up to 418 HV10. Using 316L plugs can significantly reduce weld zone hardness due to austenite dominated microstructure. Microcracks can easily emerge at and may propagate along γ–δ phase boundaries to form macrocracks. Intermittent cracks were found along the bonding interface of all the 316L plug welds, which should be caused by the relief of the residual stress.

Low-Intensity Pulsed Ultrasound (LIPUS) May Prevent Polyethylene Induced Periprosthetic Osteolysis In Vivo

We investigated the effect of local low-intensity pulsed ultrasound (LIPUS) on polyethylene debris induced periprosthetic osteolysis. The periprosthetic osteolysis model was made by injecting endotoxin-free pure polyethylene particles into the distal part of the femur canal and inserting a stainless steel plug into this femur. The effects of polyethylene and LIPUS were assessed histologically and by the shear strength test and periprosthetic bone mineral density (BMD) test. Sixteen rabbits received a stainless steel plug on one side and both polyethylene and a stainless steel plug on the other side. Three months later, the side that received polyethylene showed periprosthetic osteolysis. Subsequently, another 16 rabbits received polyethylene plus local LIPUS (200 mW/cm 2 for 20 min daily) on one side and polyethylene alone on the other side. Three months later, LIPUS effectively prevented the periprosthetic osteolysis caused by polyethylene in this rabbit model.

Application of a Simple Lumped Kinetic Model for the Catalytic Cracking Reaction of n-Butane Over the HZSM-5 Zeolite

A simple lumped kinetic model appliedton-butane catalytic cracking over synthesized HZSM-5 zeolite, with SiO2/Al2O3=484 in a stainless steel plug flow reactor under various operating conditions developed. To suitably estimate the kinetic parameters of catalytic cracking reactions of n-butane, a lumped kinetic modelconsisted of 6 reaction steps and 5 lumped compoundsconsidered. The Levenberg-Marquardt algorithm utilized toestimate kinetic parameters using MATLAB R.7.10 software.In order to confirm the significance of optimized parameters, the statistical F-test and variance analysis indicatingthe accuracy of the calculated data were employed. Furthermore, the validity of the model was confirmed. Ultimately, results from the proposed kinetic model showed excellent agreement with experimental data.

Soot characterization with laser-induced incandescence applied to a laminar premixed ethylene–air flame

Laser-induced incandescence (LII) has emerged as a promising non-invasive technique for measuring spatially and temporally resolved soot volume fraction and size. In this investigation we try to assess its performance in more detail by characterizing primary particle sizes using time-resolved LII and soot volume fractions by 2D LII. The experiments were performed at a fixed location in premixed ethylene/air flames burning on a sintered stainless-steel plug (McKenna) burner with varying values of the equivalence ratio for primary particle sizing and on the burner axis for concentration measurements. Maximum soot concentrations follow a power law behavior with equivalence ratio. The primary particle sizes obtained from LII decay curves are in good agreement with the values measured by other techniques and show a clear rise of particle size with equivalence ratio. The data analyzed with the help of a validated LII model will be useful for the further development of soot formation models.

Laminar-burning velocities of hydrogen–air and hydrogen–methane–air mixtures: An experimental study

The laminar burning velocities of hydrogen–air and hydrogen–methane–air mixtures are very important in designing and predicting the progress of combustion and performance of combustion systems where hydrogen is used as fuel. In this work, laminar flame velocities of hydrogen–air and different composition of hydrogen–methane–air mixtures (from 100% hydrogen to 100% methane) have been measured at ambient temperatures for variable equivalence ratios ( ER = 0.8 – 3.2 ). A modified test rig has been developed from the former Cardiff University ‘Cloud Chamber’ for this experimental study. The rig comprises of a 250 mm length cylindrical stainless steel explosion bomb enclosed at one end with a stainless steel plug which houses an internal stirrer to allow mixing. The other end is sealed with a 120 mm diameter round quartz window. Optical access for filming flame propagation is afforded via two diametrically opposed quartz windows in both sides. Flame speeds are determined within the bomb using a high-speed Schlieren photographic technique. This method is an accurate way to determine the flame–speed and the burning velocities were then derived using a CHEMKIN computer model to provide the expansion ratio. The design of the test facility ensures the flame is laminar which results in a spherical flame which is not affected by buoyancy. The experimental study demonstrated that increasing the hydrogen percentage in the hydrogen–methane mixture brought about an increase in the resultant burning velocity and caused a widening of the flammability limits. This experiments also suggest that a hydrogen–methane mixture (i.e. 30% hydrogen+70% methane) could be a competitive alternative fuel for existing combustion plants.

Comparison of sulfur hexafluoride and synthetic air in a simulated flux compression generator environment

Expendable, explosively driven shock tubes are used to propel aluminum flyer plates toward dense stainless steel plugs to simulate gas compression in explosive magnetic flux compression generators (FCGs). Armature velocity in a typical FCG is calculated using the Gurney method and shock tubes are designed to drive the flyer plates at similar velocities. Experiments with sulfur hexafluoride and synthetic air are presented.

Intracoronary Collagen: Effects on Coronary Collateral Circulation and the Role of Thromboxane

This study investigated the effects of intravascular collagen on coronary collateral blood flow. Collateral vessel growth was stimulated in 11 dogs by embolizing the left anterior descending (LAD) coronary artery with a hollow stainless steel plug. Experiments were performed 41 +/- 7 days after coronary embolization when collateral vessels were moderately well developed. Under alpha-chloralose anesthesia, the LAD was cannulated, and retrograde blood flow was used as a measure of collateral flow. Collagen (10-100 microg/kg) injected into the left main coronary artery caused a decrease of coronary collateral blood flow that became maximal at 3 min after injection and subsided within 9 min. At peak effect intracoronary collagen decreased retrograde flow by 53 +/- 6% from 32.7 +/- 8.2 to 16.8 +/- 3.7 ml/min (p < 0.05) with no change in systemic hemodynamics. Selective thromboxane A2 (TxA2)-receptor blockade with SQ30,741 had no effect on collateral blood flow during basal conditions but attenuated the collateral constriction in response to collagen. Thus, after SQ30,741, collagen caused only a nonsignificant decrease retrograde flow from 35.9 +/- 9.0 to 31.7 +/- 9.62 ml/min. The findings indicate that intravascular collagen exerts a potent vasoconstrictor effect on coronary collateral vessels. Attenuation of this response by TxA2-receptor blockade suggests that thromboxane released by activated platelets is the principal mediator of this response.

Effect of platelet activation on coronary collateral blood flow.

The platelet products thromboxane A2 and serotonin have been shown to cause constriction of well-developed coronary collateral vessels. This study was performed to determine whether intravascular platelet activation produced with platelet activating factor (PAF) can cause a decrease in coronary collateral blood flow. Collateral vessel growth was induced by embolization of a hollow stainless steel plug into the left anterior descending coronary artery (LAD) of adult dogs. The animals were returned to the laboratory 3 to 6 weeks later for surgical instrumentation and measurement of collateral blood flow. Collateral flow was assessed by measuring retrograde blood flow from the cannulated collateral-dependent artery. PAF (10 nmol) was injected into the left main coronary artery to allow products of platelet activation to reach collateral vessels arising from the left coronary system. PAF caused a vasoconstrictor response, which became maximal 3 minutes after injection and resulted in a 40.3+/-7.4% decrease in retrograde blood flow (32.1+/-2.1 to 19.6+/-3.2 mL/min; P<0.05). By 15 minutes after the PAF injection, both retrograde blood flow and transcollateral resistance had returned to normal. After pretreatment with the thromboxane A2 receptor antagonist SQ30, 741, the vasoconstrictor response to PAF was abolished and, in contrast to the decrease in retrograde blood flow from PAF alone, a weak vasodilator effect was unmasked. PAF caused a decrease in coronary collateral blood flow. This vasoconstrictor response required the participation of thromboxane A2.

Composite Repair of a Stainless Steel-GRP Sonar Dome

This paper describes the application of composite materials for the repair of corrosion damage on stainless-steel components of hull-mounted sonar domes on typical warships. The domes have an aerofoil shape in plan, approximately 4.08 m nose to tail, 1.27 m maximum width, and 1.83 m high. The sides (acoustic window) of the domes are made of stainless steel and the canoe-shaped bottom is made of glass-reinforced plastic (GRP) composite. A bottom-mounted stainless-steel insert and drain plug unit is used for flooding and draining the dome. Due to the severe marine environment, the stainless steel drain plug suffers extensive corrosion damage and has to be replaced frequently. A study performed to replace the stainless-steel insert and drain plug components with composite material is presented. The approach adopted is to treat the problem as a flush composite repair, whereby an area around the drain hole in the GRP canoe is cut out and replaced with a two-piece composite insert that is bonded onto the GRP canoe. Both the insert and plug are made of glass-reinforced composite material. Details of the material selection, design, fabrication, and process specification for the repair, as well as the challenges involved in undertaking this repair are discussed.

Preliminary experience with a novel model assessing In vivo mechanical strength of bone grafts and substitute materials

A novel canine tibia model was used to evaluate four bone graft materials: autologous cortical bone, allograft cortical bone, hydroxyapatite/tricalcium phosphate (HA/TCP) ceramic granules, and a HA/TCP and collagen composite. Mechanical material properties were assessed using custom-designed stainless steel plugs for control of graft volume and interface surface area. These plugs held the bone graft materials in the cortex of the tibia shaft and allowed in vivo mechanical testing. After 6 months of ad lib weight bearing, the grafts were harvested and tested in torsion. The samples in each animal were compared with the test plugs into which new bone had grown without the addition of graft. Control bone peak shear strength averaged 47 (+/- 8.3) MPa (6.78 +/- 1.2 kpsi). Compared on the basis of peak torque, stiffness, and energy to peak torque, no significant differences were found among any of the graft materials or control bone. Histologic examination revealed the materials to be osteoconductive with the extensive formation of dense, compact cancellous bone. The new bone in the autograft and allograft samples completely filled the available space, whereas gaps persisted in the synthetic ceramics.

Triage methodology for the evaluation of implant-bone interfaces

Stainless steel plugs coated with and without Al 2O 3, TiO 2 and Nb 2O 5 were inserted into canine femora in order to develop a methodology of rapid identification of appropriate specimens for deeper analysis of implant-bone interfaces. This approach is especially meaningful in areas where research funds are scarce. After a maximum follow-up period of 52 wk, bone segments containing plugs were radiographed using conventional techniques, high resolution techniques (which allowed a good preliminary evaluation) and microradiography. Analysis by X-ray fluorescence spectrometry indicated release of the materials by the implants. Microdensitometry of the microradiographs allowed a precise thickness determination of the tissue formed around the implants.

Thermal-Fluid Model for Weld Pool Geometry Dynamics

This paper describes an experimental and analytical program to provide a predictive weld pool modeling technique useful as one component of a feed back control automatic welding machine. Stationary arc experiments were performed with stainless-steel plugs and showed two different regimes in the growth of the weld pool. Initially the surface tension driven flow was dominant in the shaping of the pool (t&lt;3 s). Once enough material was molten, the electromagnetic (E-M) forces became the dominant factor. This behavior was also observed for the moving arc cases. Detailed measurements of the pool shape were made for steady and transient conditions. A thermal-fluid model of the weld pool was developed for the case of a stationary arc in which a deep paraboloidal pool is formed. This model uses the current and heat distribution at the anode surface as inputs. Matching of convective and conductive heat fluxes along the melt boundary was used to predict the weld pool shape. The conductive heat flux on the solid side was calculated by the finite element method. The convective heat flux on the liquid side was calculated by solving the fluid and heat transfer equations assuming a single cell circulation flow inside the weld pool. For the stationary arc cases under consideration, the E-M force field was found to dominate the flow pattern. This method was capable of determining the transient in weld pool geometry for changes in different process conditions, e.g., arc length, pulsed current. Comparison between experiments and the model showed agreement of weld pool size (top width and penetration) within 10 percent. This modeling technique can be extended to analyse weld pools with multi-cell circulation patterns which are encountered in the moving arc and the stationary arc cases with a shallow pool.

Chromite formation by shock-wave compression

Chromite formation was observed in experiments with a flash-heating hemispherical-implosion system, when a cylindrical steel sample holder, with stainless-steel plug, containing a graphite/iron mixture was compressed by the implosion. The formation of chromite was observed and verified by x-ray diffraction, scanning electron microscopy, and chemical microanalysis. The diffusion rates of Cr from the plug to the sample were as high as 102–103 cm2 s and growth rates of chromite crystals were as high as 0.3–0.4 ms−1. The foregoing could be inferred from the observations of the recovered specimens. Possible ways of chromite formation and the causes for the unusually high diffusion and crystal-growth rates are discussed.

A comparison of specimen stage surface temperature and the GA‐1 control unit reading in Balzer's Freeze fracture microtome cold stage

AbstractThe cold stage specimen surface in our Balzer's 300 Freeze‐etch instrument, averages 29–43°C warmer than the reading on the GA‐1 stage temperature control unit. By introduction of Indium foil seals above and below the stainless steel plug in the stage tower, the specimen cold stage surface temperatures were still 9–10°C warmer than the GA‐1 reading. After replacing the stainless steel plug with a copper plug and using Indium seals, the cold stage specimen surface was brought within 2.6°C of the GA‐1 temperature reading. In addition, the copper plug, Indium seal modified stage cools about two times faster in going from –100°C to –150°C than the normal stainless steel stage modified with Indium seals.