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The purpose of this study is to report our initial experience with a new fully covered metallic stent with a novel design (AXIOS) to prevent migration and fluid leakage, in the drainage of pancreatic fluid collections (PFC).We included nine patients from four Spanish centers undergoing endoscopic ultrasound (EUS)-guided drainage of PFC with placement of an AXIOS stent. The lesions were accessed via transgastric (n = 7), transesophageal (n = 1), and transduodenal (n = 1) by using a novel access device (NAVIX) in six cases or a 19-G needle in three. Patients were individually followed prospectively for procedure indications, demographic data, previous imaging techniques, technical aspects, clinical outcomes, complications, and follow-up after endoscopic drainage.The mean size of lesions was 105 ± 26.3 mm (range, 70-150). In six cases, cystoscopy was performed through the stent, including necrosectomy in two. Median procedure time was 25 ± 13 min. A median number of two sessions were performed. The technical success rate was 88.8 % (8/9) due to one failure of the delivery system. One patient developed a tension pneumothorax immediately after transesophageal drainage. No migrations were reported, and all stents were removed easily. All patients had a successful treatment outcome achieving complete cyst resolution. Mean time to stent retrieval was 33 ± 40 days. Mean follow-up was 50 ± 1.3 weeks (range, 45-55), and only one patient presented a recurrence 4 weeks after the stent removal. Furthermore, comparison with ten previous consecutively recruited PFC cases drained by EUS-guided using plastic pigtail stents was done. Technical and clinical successes were similar. However, two stent migrations, two recurrences, and two complications were found. The number of stents used (n = 15) and the median procedure time (42.8 ± 3.1 min) were significantly higher.Drainage of PFC using dedicated devices as this novel metallic stent with special design seems to be an effective, feasible and safe alternative technique.

The introduction of grooves, micropores, and other forms of surface geometric modifications onto the mating seal plates has been performed to enhance the gas face seal performance. Reducing fluid leakage through the seal surface has been the main motivation for the development of efficient sealing technology for industrial turbomachinery. Pressure dams are generally etched on the seal inner and outer radii to improve even more the seal capability of reducing the gas leakage to atmosphere. This paper presents a finite element analysis carried out to determine the opening force, the flow leakage and the dynamic force coefficients of flat gas face seals with pressure dams operating under stringent conditions. Several curves of steady-state and dynamic seal performance characteristics depict the influence of the pressure dam position and width on the seal performance and efficiency.

This paper presents a surface and subsurface geochemical survey of the Buracica EOR-CO2 field onshore Brazil. We adopted a methodology coupling the stable isotopes of carbon with noble gases to investigate the adequacy of geochemical monitoring to track deep fluid leakage at the surface. Three campaigns of CO2 flux and concentration in soils were performed to understand the CO2 variability across the field. The distribution of the CO2 soil contents between 0.8 and 14% is in great part controlled by the properties of the soil, with a first-order topographic dependency. These results, together with a δ 13 CCO2 between –15 and –23‰, suggest that the bulk of the soil CO2 flux is biological. The gas injected and produced at numerous wells across the field showed a great spatial and somewhat temporal heterogeneity with respect to molecular, δ 13 CCO2 and noble gas compositions. This heterogeneity is a consequence of the EOR-induced sweeping of the petroleum fluids by the injected CO2 , producing a heterogeneous mixing controlled by the production scheme and the distribution in reservoir permeability. In light of the δ 13 CCO2 found in the reservoir, the stable isotopic composition of carbon was insufficient to track CO2 leaks at the surface. We demonstrate how noble gases may be powerful leak discriminators, even for CO2 abundances in soils in the bottom range of the biological baseline (~1%). The results presented in this study show the potential of geochemical monitoring techniques, involving stable isotopes and noble gases at the reservoir and soil levels, for tracing CO2 in CCS projects.

Several vaccines, diagnostic tests, and medications are currently delivered intradermally, and it is likely that this route of administration will grow in importance. A phase I clinical study was conducted to evaluate the intradermal (ID) adapter, a prototype intradermal delivery aid, for safety and precision of injection. Healthy adult volunteers received two injections each of 0.1 mL of sterile saline solution in the upper deltoid region of the arm using the ID adapter. Injection performance was determined by the proportion of injections delivered to the dermal layer by measuring wheals and fluid leakage, and through ultrasound imaging. Of the 40 study injections, 100% were determined to be successful intradermal injections. Leakage of liquid at the injection site was negligible. Performance was similar with the bevel orientation both upward and downward. Minor bleeding and skin abrasions were the only reported adverse events. Injections were well tolerated based on self-reporting of pain of injection. Based on these results, the ID adapter appears to be safe and effective as an alternative to the Mantoux method of ID delivery for future use in clinical evaluations of ID delivery of vaccines, skin tests, and other drugs.

Persistent posttraumatic CSF fluid leakage may present a challenge to manage. Failure to address the leakage may result in complications such as meningitis, septicemia, radiculopathy, muscle weakness, and back pains. While the majority of the leakages may be managed conservatively, large dura defects as a result of gunshot wounds or motor vehicle accidents are best managed by surgical interventions. This may range from primary closure of the defect to fascial grafts, adhesive glues, and flaps. We present our experience with the use of flaps in a patient who had sustained such wounds in the thoracic spine. An island latissimus dorsal flap and a perforator fasciocutaneous flap were used to close the defect. Postoperatively the patient recovered well and the wounds healed without any complications.

Three dimensional solid-fluid interaction numerical analysis models of both the finger seal with herringbone-grooved pad and the finger seal with herringbone-grooved rotor were established in order to study the performance of hydrodynamic finger seal. The models investigated fluid radial under pad force and fluid leakage as a function of both the rotor speed and the high- to low-pressure differential. It was shown that the finger seal with herringbone-grooved structure in pad or in rotor could bring lift force under the finger pad so as to keep the finger seal in non-contacting status. For the two types of finger seal, their load carrying ability and fluid leakage varying with the pressure differential were almost same. In the same velocity of rotor surface, the load carrying capacity of the finger seal with herringbone- grooved rotor was greater and the leakage was less than that of the finger seal with herringbone-grooved pad respectively. With the conditions of rotor structure allowing, it is suggested to select the finger seal with herringbone-grooved rotor first for designing the hydrodynamic finger seal with herringbone-grooved structure.

Image processing has provided powerful techniques to extract from the acoustic signals the desired information on evaluation for leakage existence, leakage rate, and searching for leakage location, etc. The imagery NDE data available can add additional and significant dimension in nondestructive evaluation(NDE) information and thus for exploiting in applications. To extract such information the use of advanced image processing techniques is much needed. In recent years, there has been much increased use of acoustic signal image processing techniques in acoustic NDE. This approach will increase the efficiency of inspection procedures and reduce inspection time. In this paper we are concerned only with This paper is concerned mainly with the use of advanced image processing techniques in valve leakage detection and advanced image restoration and enhancement methods, which attempt to evaluate promptly by a visualization method the acoustic sources while detecting the valve leakage.

Elastomeric seals are devices that are widely used to prevent fluid leakage through the interface of mating parts. In this paper, we study the leak characteristics of a representative elastomeric s...

In order to prevent the occurrence of cementing fluid leakage in low leakiness formation and protecting reservoir effectively, low density cement system is widely used. As the use of lightening admixture to reduce the density in low density cement system, the cement acoustic impedance of low density cement system is different from conventional density, it can not reflect the real cementing quality when using the criteria of conventional density cement cementing quality evaluation to evaluate the cement job quality of low density cement. Targeted at this problem, this paper conducted a method to improve the criteria of evaluation of cementing for low density cement. Studies have shown that the compressive strength and the acoustic impedance has a good linear relationship in different types of low density cement conserved 24 h and 48 h, so we put forward a method to improve the evaluation of cementing quality of low density cement based on the compressive strength of low density cement.

Fundamental experiments on fluid leakage from tapered seals due to sleeve rotation were carried out. The apparatus was designed so that the surface tension, which generates a sealing function, acts effectively in terms of size and accuracy similar to its behavior in an actual device. The shapes of the interface (boundary surface of two kinds of fluids) at several rotational speeds were measured with an ultra-focus laser microscope, and the features of fluid leakage were observed with a high-speed camera. The experimental results of the positions of the bottoms of the interface coincided comparatively well with the theoretical ones. We also verified that the threshold speeds in the experiment on fluid leakage could broadly be estimated by using the theoretical ‘ultimate’ and ‘triggering’ critical rotational speeds of the sleeve.

OBJECTIVES: To evaluate the sealing ability of five root canal sealers, including two experimental cements (MBP and MTA-Obtura) using the fluid filtration method. MATERIAL AND METHODS: Teeth were divided into 5 study groups: G1-AH Plus; G2-Acroseal; G3Sealapex; G4-MBP; G5-MTA-Obtura; and two controls. Chemical-mechanical preparation was performed with ProFile rotary nickel-titanium instruments 1 mm short of the apical foramen. The sealing ability was evaluated by fluid filtration at 15, 30, and 60 days. RESULTS: The statistical analysis showed significant difference between the materials at different periods (p

In vitro shock wave lithotripsy (SWL) research is typically performed utilizing wet coupling lithotriptors with a mesh basket model. This model does not take into account shock wave energy attenuation through tissue. Models using dry coupling lithotriptors rely on immersion chambers and face similar limitations. Ordnance gelatin (OG) displays strength and viscous properties similar to human tissue and is therefore widely used for ballistic tissue injury research. We present our initial experience using an OG tissue simulating scaffold for dry coupling SWL research. Using 10% OG prepared in a disc-shaped mold (five stone wells/gel), we tested the model using a Modulith SLX-F2 lithotriptor and artificial stone phantoms. Following a test of concept run on an empty gel mold and a material integrity check for leakage, we shocked 60 stones (30 narrow focus [NF], 30 wide focus [WF]) in human pooled urine. Half were shocked using gels containing open-ended wells with the remainder closed-ended wells. Fragmentation coefficients (FC) were calculated across both foci and gel models. All gels successfully completed 5,000 shocks (1,000/well) without loss of gel integrity or fluid leakage. The mean FC using open-ended wells was 77.9 ± 7.6% NF and 74.4 ± 4.8% WF, and for closed wells 75.9 ± 8.0% NF and 67.1 ± 3.5% WF. The total model cost including the preparation of gels and begostones was assessed at approximately $1 per stone (Canadian). Ordnance gel serves as an excellent surrogate tissue shockwave scaffold providing an easily manufactured, reproducible and inexpensive model for dry coupling SWL research.

Leakage of oral secretions past endotracheal tubes (ETT) has been implicated in ventilator associated pneumonia. The aim of this bench study was to compare the ability of current generation ETT cuffs to prevent fluid leakage and to determine the specific mechanical ventilator settings that affect movement of fluid across an inflated ETT cuff.Using a 2.3-cm internal diameter (ID) tracheal model and simulated ventilatory support, we evaluated the impact of cuff pressure (20 and 30 cmH(2)O), positive end-expiratory pressure/continuous positive airway pressure (PEEP/CPAP, 0-15 cmH(2)O), peak inspiratory pressure (PIP, 15-45 cmH(2)O), and mode of ventilation (volume control, volume assist/control, pressure control, pressure assist/control, and CPAP) on leakage of fluid past the ETT cuffs of 16 ETTs. The tracheal model was configured in the vertical position with 35 ml of vitaminwater(®) on top of the inflated ETT cuff and mechanically ventilated. Fluid leakage past the cuff was determined by calculating the volume change in the tracheal model after each 30-min ventilation period. Initially five 8.0-mm-ID ETTs of each manufacturer type were evaluated at baseline ventilator settings. Tubes allowing a consistent leak within two SD of the mean leakage for the five tubes were numbered in consecutive order. A single tube from this group was then randomly selected for detailed evaluation.Cuff leakage varied among ETT types (p0.0001); median leak volume 6.0 ml (0.6-15.1) across all tubes under all conditions. Cuff leakage was inversely related to PEEP level, cuff pressure, and PIP except when PEEP was set at 15 cmH(2)O (all p0.0001). In addition, cuff leak varied among modes (p = 0.035).Cuff leakage varies greatly among ETT types and is affected by cuff pressure, PEEP, PIP, and mode.

The detection of acoustic emission (AE) signals produced by liquid and gas leakage through valves can be related directly to the qualitative leakage rate. This allows for cost estimation of losses in processes for several industries. However, to find out the relationship between qualitative leakage rate and AE signal large amounts of experimental data is needed. This paper presents a theoretical investigation of the acoustic emission to detect the internal leakage rate through a valve and experimental validation. The AE signals generated by internal liquid and gas leakage through valves were characterised. The effect of the influenced factors of leakage rates, inlet pressure levels, valve sizes and valve types, on AE parameter, AE RMS , were studied and explained. The results of theoretical and experimental showed that AE signal power computed from the power spectral density (PSD) correlated well with influenced factors of leakage rates. Finally, a novel and inexpensive AE instrument has been invented for predicting qualitative leakage rate using a micro processor and derived relationship.

Seals are extremely useful devices to prevent fluid leakage. We present an effective-medium theory of the leak rate of rubber seals, which is based on a recently developed contact mechanics theory. We compare the theory with experimental results for seals consisting of silicon rubber in contact with sandpaper and sand-blasted PMMA surfaces.

Conclusions: By testing 125 samples, we confirmed that Cochlin-tomoprotein (CTP) is present in the perilymph, not in cerebrospinal fluid (CSF). Perilymph and CSF exist in two distinct compartments, even in the case of a malformed inner ear with a bony defect in the lamina cribrosa, as described here. Cochleostomy might have suddenly decreased the perilymph pressure, allowing the influx of CSF into the inner ear resulting in profuse fluid leakage, first perilymph then CSF. Objectives: The first purpose of this study was to further confirm the specificity of the perilymph-specific protein CTP that we reported recently. Secondly, we assessed the nature of the fluid leakage from the cochleostomy using the CTP detection test. Methods: A standardized CTP detection test was performed on 65 perilymph and 60 CSF samples. Samples of profuse fluid leakage collected from cochleostomy during cochlear implantation surgery of one patient with branchio-oto-renal (BOR) syndrome were also tested by the CTP detection test. Results: CTP was detected in 60 of 65 perilymph samples but not in any of the CSF samples. The leaked fluid was shown to contain CTP, i.e. perilymph, at the outset, and then the CTP detection signals gradually disappeared as time elapsed.

This paper is devoted to the modeling of fluid leakage through a shell in case of impact loading. The modeling of the fluid and the shell is based on SPH formulation. The proposed model is devoted to the prediction of failure of a shell filled with fluid. This paper is devoted to the numerical modeling of fluid–structure interaction. The pinballs technique is used for contact analysis. Numerical predictions are compared with analytical as well as with an original experiment. Copyright © 2009 John Wiley & Sons, Ltd.

Summary Central venous catheters (CVC) are widely used in the care of chronically ill patients, particularly those with intestinal failure receiving long-term parenteral nutrition. Serious complications such as infection, obstruction and catheter related thrombus are well recognised. We report two patients who developed localized pain on flushing the catheter. Radiological investigation revealed fluid leakage from the CVC, from a fracture within the skin tunnel in one case, and from the intravascular segment, with venous backflow probably related to a sleeve thrombus, in the other.

Introduction Parylene coating was added to the silicone layers of the American Medical Systems (AMS) 700 controlled expansion (CX) penile prosthesis cylinders in January 2001. The coating was placed on non-tissue contacting silicone surfaces to increase lubricity, reduce friction, and silicone wear Aim We compared mechanical reliability of the original and Parylene-enhanced AMS 700 CX in a large single surgical group series Methods Seven hundred seventy-five consecutive patients receiving the AMS 700CX prosthesis (596 first time [virgin] and 179 revisions) were followed for 3 years. Four hundred fourteen received the non-coated model and 361 received the Parylene-coated device. Revision-free survival was estimated using the Kaplan–Meier product limit method and compared using the log-rank test. Main Outcome Measures We calculated overall survival from revision for any reason and survival from mechanical problems such as fluid leakage, cylinder, connector or tubing breakage, pump or reservoir defects. Results For the entire series (virgin + revised) the 3-year revision free survival for any cause improved from 78.6% for non-coated to 87.4% for the Parylene-coated implants. Freedom from mechanical breakage showed similar improvement from 89.2% for the non-coated to 97.5% for enhanced models. Conclusion This study documents that short-term mechanical reliability and survival from revision for any cause is significantly increased with Parylene-coated AMS 700CX cylinders compared with the earlier AMS 700CX model with non-coated cylinders. Salem EA, Wilson SK, Neeb A, Delk JR, and Cleves MA. Mechanical reliability of AMS 700 CX improved by Parylene coating. J Sex Med 2009;6:2615–2620.

Despite radiotherapy and chemotherapy, chylous ascites occur frequently in patients with ovarian cancer. We report a case of ovarian cancer with massive chylous ascites and describe the use of lymphoscintigraphy to demonstrate pelvic lymph nodes and lymphoid fluid leakage to the pelvic floor.

The Nordland Group in the Southern Viking Graben hosts seismic chimneys, represented by anomalies in seismic data and resid- ual methane accumulations. These anomalies are generally interpreted as focused fluid flow structures, and thus pose the risk of potential fluid leakage by geological subsurface utilization. Our aim was to assess if excess pore pressure, resulting from buoy- ancy effects due to upward-migrating methane in the Utsira Formation may be responsible for formation of these anomalies. Our hydromechanical simulation results demonstrate that tensile failure in the Nordland Group already occurs before the maximum methane column heights develop in the Utsira Formation below.

Background When conventional high-volume, low-pressure cuffs of endotracheal tubes (ETTs) are inflated, channel formation due to folds in the cuff wall can occur. These channels facilitate microaspiration of subglottic secretions, which is the main pathogenic mechanism leading to intubation-related pneumonia. Ultrathin polyurethane (PU)-cuffed ETTs are developed to minimize channel formation in the cuff wall and therefore the risk of microaspiration and respiratory infections. Methods We systematically reviewed the available literature for laboratory and clinical studies comparing fluid leakage or microaspiration and/or rates of respiratory infections between ETTs with polyvinyl chloride (PVC) cuffs and ETTs with PU cuffs. Results The literature search revealed nine in vitro experiments, one in vivo (animal) experiment, and five clinical studies. Among the 9 in vitro studies, 10 types of PU-cuffed ETTs were compared with 17 types of PVC-cuffed tubes, accounting for 67 vs. 108 experiments with 36 PU-cuffed tubes and 42 PVC-cuffed tubes, respectively. Among the clinical studies, three randomized controlled trials (RCTs) were identified that involved 708 patients. In this review, we provide evidence that PU cuffs protect more efficiently than PVC cuffs against fluid leakage or microaspiration. All studies with leakage and/or microaspiration as the primary outcome demonstrated significantly less leakage (eight in vitro and two clinical studies) or at least a tendency toward more efficient sealing (one in vivo animal experiment). In particular, high-risk patients intubated for shorter periods may benefit from the more effective sealing capacity afforded by PU cuffs. For example, cardiac surgery patients experienced a lower risk of early postoperative pneumonia in one RCT. The evidence that PU-cuffed tubes prevent ventilator-associated pneumonia (VAP) is less robust, probably because microaspiration is postponed rather than eliminated. One RCT demonstrated no difference in VAP risk between patients intubated with either PU-cuffed or PVC-cuffed tubes, and one before-after trial demonstrated a favorable reduction in VAP rates following the introduction of PU-cuffed tubes. Conclusions Current evidence can support the use of PU-cuffed ETTs in high-risk surgical patients, while there is only very limited evidence that PU cuffs prevent pneumonia in patients ventilated for prolonged periods. Electronic supplementary material The online version of this article (doi:10.1186/s13054-016-1380-8) contains supplementary material, which is available to authorized users.

Fluid leakage out of mechanical equipment such as gearboxes, hydraulic systems, or fuel tanks could cause serious problems and thus should be avoided. Seals are extremely useful devices for preventing such fluid leakages. We have developed a theoretical approach for calculation of the leak rate of stationary rubber seals and the friction force for dynamic seals. The theory is based on a recently developed theory of contact mechanics, which we briefly review. To test the theory, we have performed both simple model experiments and experiments on engineering seal systems. We have found good agreement between the calculated and measured results, and hence our theory has the potential to improve the future design of efficient seals.

The mechanism of fluid leakage trough the free volume between rough surfaces in contact is relevant in physics and in many engineering applications. In the present study, the normal contact problem between randomly generated fractal rough surfaces is solved using the boundary element method. Then, an algorithm for the evaluation of the network involved in the percolation of fluid is proposed. Numerical results are synthetically collected in diagrams relating the free volume involved in the percolation to the dimensionless statistical parameters of the rough surface

It is shown that when sucker-rod pumps are used, fluid leakage in seals of plunger-cylinder and valve pair through hole and radial slot is proportional to the area of the flow section and is also dependent on the shape of the latter. A new type of mechanical seal has been developed that reduces leakage significantly and increases efficiency and nonfailure operating life of piston or plunger pumps.

The objective of this study was to compare fluid leakage across endotracheal tube cuffs using a three-dimensional (3D)-printed human tracheal model that anatomically simulates the human trachea. We made two models based on computed tomography data of the neck and chest. Using a Mallinckrodt Hi-Lo™ (HL), ThinCuff(®) (TC), and Mallinckrodt TaperGuard™ (TG), we sequentially measured the amount of fluid leakage across each endotracheal tube cuff after applying saline or viscous liquid above the cuff. The TG allowed significantly less leakage than the HL and TC with both saline and the viscous liquid. Our study, using a 3D-printed tracheal model, indicated that a conical-shaped endotracheal tube cuff significantly reduces fluid leakage across the cuff compared with conventional cylindrical-shaped cuffs made of polyurethane or polyvinylchloride, contrary to the results of a previous study using a solid cylindrical structure.

Dina Joy Abulon,1 Martin Charles,2 Daniel E Charles21Global Medical Affairs, Alcon Laboratories, Inc., Lake Forest, CA, USA; 2Centro Oftalmológico DrCharles, Buenos Aires, ArgentinaPurpose: To compare the effects of valved and non-valved cannulas on intraocular pressure (IOP), fluid leakage, and vitreous incarceration during simulated vitrectomy.Methods: Three-port pars plana incisions were generated in six rubber eyes using 23-, 25-, and 27-gauge valved and non-valved trocar cannulas. The models were filled with air and IOP was measured. Similar procedures were followed for 36 acrylic eyes filled with saline solution. Vitreous incarceration was analyzed in eleven rabbit and twelve porcine cadaver eyes.Results: In the air-filled model, IOP loss was 89%–94% when two non-valved cannulas were unoccupied versus 1%–5% when two valved cannulas were unoccupied. In the fluid-filled model, with non-valved cannulas, IOP dropped while fluid leaked from the open ports. With two open ports, the IOP dropped to 20%–30% of set infusion pressure, regardless of infusion pressure and IOP compensation. The IOP was maintained in valved cannulas when one or two ports were left open, regardless of IOP compensation settings. There was no or minimal fluid leakage through open ports at any infusion pressure. Direct microscopic analysis of rabbit eyes showed that vitreous incarceration was significantly greater with 23-gauge non-valved than valved cannulas (P

The maximum sphere method and the minimum cross-section method are proposed to calculate the interlobe clearance between two mating screw rotors and to determine the shapes and sizes of all the leakage paths. These two methods are inspired by the red-lead and tooth-contact pattern and can be used to evaluate the interlobe leakage and to design the mating rotor profiles. The combined results of these two methods provide the basis for an exact evaluation of the fluid leakage, and this feature increases flexibility in geometrical designing and manufacturing of the screw rotors. These methods are also suitable for non-conjugate rotors and contribute to thermal analysis and optimum programming.

In order to understand the kinematics which likely facilitated the speedy rupturing process of the 1999 Mw 7.6 Taiwan ChiChi earthquake, we examined exposed rocks in the Taiwan Slate belt, where the pressure and temperature conditions most resembled the hypocentre of the Chi-Chi earthquake, i.e. subgreenschist facies. Field observations and composition analyses of the silicified vein-rich zones beneath the duplex structure suggest that impermeable slate layers may serve as cap rocks for confining deep-seated fluids. These fluids most likely come from the Taiwan metamorphic complex at deeper depths by the dehydration and decarbonation reactions (or partial melting). In addition, the gouge zone of a link fault above the detachment also indicates the presence of overpressured fluids during faulting. It is probable that episodic leakage of the confined fluid reservoirs may provide essential fluids for fault lubrication during earthquake ruptures.

This paper covers the study of hydromechanical deep drawing of cylindrical steel cups using a controllable sealing mechanism between the blank and the draw ring. Precise control of the counter pressure curve over the punch stroke in hydromechanical deep drawing is difficult to accomplish due to fluid leakage. A controllable sealing mechanism has been developed and tested; this resulted in a die set designed to withstand fluid pressures up to 200 MPa with draw ratios up to 3.0. A micro-metering pressure control valve is used to limit the developed counter pressure to avoid die breakage. Furthermore, the ability of transferring complex microstructures from the punch onto the blank surface is investigated.

Objective. The purpose of this in vitro study was to determine the minimum depth of mineral trioxide aggregate (MTA; ProRoot; DENTSPLY/Tulsa Dental, Tulsa, Okla) required to maintain an apical seal following root resection. Study design. In 10 instrumented teeth, MTA was used to obturate the apical 6 mm of the root canal and was allowed to set for 48 hours. Leakage was determined by means of a fluid filtration method at a pressure of 20 cm H2O. Leakage was measured before root resection, and after 3, 4, 5, and 6 mm apical resections. Data were analyzed by means of a Kruskal-Wallis one-way analysis of variance with P

In geological underground utilization, operating and abandoned wells have been identified as main potential leakage pathways for reservoir fluids. In the scope of the well abandonment procedure currently carried out at the Ketzin pilot site for CO2 storage in Germany, we implemented a hydro-mechanical wellbore model to assess the integrity of the entire wellbore system. Thereto, we investigated the impacts of stress changes associated with site operation and abandonment, including the final casing removal and cement backfill to be undertaken for well abandonment. Simulation results show a high unlikeliness of potential formation of fluid leakage pathways in the wellbore system.

In pressure vessels and piping the leak-before-break (LBB) assessment method is employed to avoid any catastrophic failure prior to a detectable leakage. One of the most important parameter, the leak rate, is investigated in the present paper by means of the Monte Carlo method. A brief review is carried out with emphasis on aspects such as crack growth, crack size with detectable leakage, crack opening area and leak rate. Issues concerning the property and behaviour of multiple cracks are also covered along with a review of the characteristics of leak rate through distributed multiple cracks using a statistical simulation method. The simulation results show that the effect of multiple cracks is quite significant to the LBB concept. Both the relationship between leak rate and crack length (or time) and the statistical characteristics of the leak rate are considerably different for different initial crack conditions.

The authors have established strict formulation of mathematical equations for permeability determination by transient pulse method and extended the formulation to the specified cases, i. e., the authors have applied the transient pulse method to the hollow cylinder specimen and extended it's application to the case where fluid leakage from the pressure cell is taken into account. In the hollow cylinder specimen, fluid leakage along specimen boundary can be easily prevented.Intrinsic permeability k was given by the following formula:k=ακμ log(R0 / Ri) / 2πL V1 V2 / V1 + V2where α is the value to be determined from test data, κ is fluid compressibility, μ is fluid viscosity, R0, Ri and L are the outer radius, the inner radius and the height of the hollow cylinder specimen, respectively. V1 and V2 are capacity of the spaces communicating with the inside and the outside of the hollow cylinder specimen in the pressure cell.The authors developed a simple apparatus for permeability measurement. Pneumatic permeability tests using the apparatus were carried out and the permeability of a specimen made of limestone was determined. The permeability test takes only a few hours even for a specimen made of low-permeability rock because of low viscosity of air.

The choice of gasket type for flanged connections has typically been determined on the basis of temperature, pressure, and chemical nature of the contained fluid; sealability; ease of handling and installation; expected service life; comparable cost; and other factors. Of ever increasing importance is the environmental performance of the selected gasket with an emphasis on fugitive emissions reduction. All gaskets have some level of fluid leakage but this may vary significantly depending on the type selected. A practical tool using Microsoft® Excel® has been developed that can help predict anticipated fugitive emissions of gaskets for which Room Temperature Testing (ROTT) data are available. The construction and application of this tool are described and a relative comparison of tightness parameters and projected fugitive emissions for example gasket types are documented.Copyright © 2014 by ASME

Preserved pericardium in contact with blood is not thrombogenic, therefore avoiding the use of anticoagulants, and has excellent mechanical properties. Our objective is to take advantage of these characteristics and build a pulsatile ventricular assist device (VAD) with pericardium used as the inner lining of the blood chamber. A mold is used for the tanning of the pericardium, rendering it with an exact shape. A flexible polymeric structure is designed to serve as a base for the pericardium, guiding it and limiting its rate of strain. It consists of two halves, which when outfitted with the interior pericardium lining and connected to each other, form the blood chamber. This assembly is housed in rigid polyvinyl chloride (PVC) shells making up the air chamber for the pneumatic activation. Valves are likewise made of pericardium. Sealing of the chambers was tested statically up to 300 mm Hg with no air or fluid leakage. The device was tested for 60 continuous days in a mock loop, demonstrating hydrodynamic performance adequate for ventricular assist. Micrographs (confocal laser and scanning electron microscopy) were obtained of several pericardium areas, especially on the flexing regions that are a transition between the wet and dry regions. No sign of damage to the pericardium was observed either with the naked eye or at the microscopic level. From the hydraulic performance and materials viewpoints, a completely pericardium-lined pulsatile VAD displaying a polymeric structure that avoids unpredictable bending and limits strain is feasible. The results warrant further studies regarding biocompatibility and strength advantages.

The problem of fluid seepage through the cracked walls of pressure vessels has been examined. A simplified two-dimensional computational fluid dynamics (CFD) model of water passing through a narrow crack has been constructed and the results compared with published data. The CFD modelling process was validated by experimental work on two geometrically identical idealized crack bodies. The flowrate of air through the crack as a function of opening displacement was measured using the smaller apparatus, and the corresponding flow patterns were observed using smoke particles in the larger air flow apparatus. Four distinct flow regimes have been identified when the opening displacement of the crack is less than 3 times the surface roughness of the crack faces.

The effect of fluid leakage into insulation material is considered, where the combustible fluid spread over the inner fibres of the material is both slowly oxidizing and undergoing evaporation/desorption. It is found, in particular, that the constant supply of fuel can lead to unexpected oscillatory behaviour in regions of parameter space which would otherwise have been considered safe. In particular, the case of an extremely slow rate of supply of fluid can be the most deceptive in terms of the possibility of ignition. *An early version of this paper was presented at the 16th ICDERS, Cracow, Poland, 4–8 August 1997.

A case of cerebro-spinal fluid leakage occurring after the removal of a pedicular screw is reported. It allowed emphasizing the frequency of the dural tears in spinal surgery, particularly when pedicular screws are used. Moreover, the removal of screws having involved neurological complications can induce other lesions, such in the reported case. This removal procedure is not benign and requires precautions and a monitoring identical to the other spinal procedures.

Dear Editor, The recent report on fine needle aspiration was very interesting. Akhavan-Moghadam noted that “fine needle aspiration (FNA) is a useful atraumatic diagnostic technique with high diagnostic accuracy, which can provide a highly sensitive and low false positive diagnosis in patients with nonthyroidal masses” (1). It is interesting to discuss the diagnostic properties of FNA and its harmfulness. According to a recent study by Wharry et al., it was reported that the false negative results were as high as 10.4 %, which may cause problems in diagnostic process (2). The needle size and experience of cytologist are the main factors that determine the false results (3). Furthermore, although FNA is classified as a minimally invasive technique, there are still some serious complications such as cyst fluid leakage, pneumothorax, anaphylactic reaction and thromboembolism that should be considered by all practitioners performing FNA (4).

Risk assessment is the process of assessing risks and factors influencing the level of safety of a project. It involves researching how hazardous events or states develop and interact to cause an accident. The risk assessment effort should be tailored to the level and source of technical risk involved with the project and the project stage being considered. The assessment of technical risk will take different forms in different stages of the project. Pipeline flow risk mainly includes fluid leakage and blockage happening in the pipelines. This chapter describes the application of Quantitative Risk Assessment (QRA) for the blockage in the oil and gas pipelines.

Microaspiration of subglottic secretions through channels formed by folds in high volume-low pressure poly-vinyl chloride cuffs of endotracheal tubes is considered a significant pathogenic mechanism of ventilator-associated pneumonia (VAP). Therefore a series of prevention measures target the avoidance of microaspiration. However, although some of these can minimize microaspiration, benefits in terms of VAP prevention are not always obvious. Polyurethane-cuffed endotracheal tubes successfully reduce microaspiration but high quality data demonstrating VAP rate reduction are lacking. An analogous conclusion can be made regarding taper-shaped cuffs compared with classic barrel-shaped cuffs. More clinical data regarding these endotracheal tube designs are needed to demonstrate clinical value in addition to in vitro-based evidence. The clinical usefulness of endotracheal tubes developed for subglottic secretions drainage is established in multiple studies and confirmed by meta-analysis. Any change in cuff design will fail to prevent microaspiration if the cuff is insufficiently inflated. At least one well-designed trial demonstrated that continuous cuff pressure monitoring and control decrease the risk of VAP. Gel lubrication of the cuff prior to intubation temporarily hampers microaspiration through sludging the channels formed by folds in high volume-low pressure cuffs. As the beneficial effect of gel lubrication is temporarily, its potential to reduce VAP risk is probably nonsignificant. A minimum positive end-expiratory pressure of at least 5 cmH(2)O can be recommended as it reduces the risk of microaspiration in vitro and in vivo. One randomized controlled study demonstrated a reduced risk of VAP in patients ventilated with PEEP (5-8 cmH(2)O). Regarding head-of-bed elevation, it can be recommended to avoid supine positioning. Whether a 45 degrees head-of-bed elevation is to be preferred above 25-30 degrees head-of-bed elevation remains unproven. Finally, the routine monitoring of gastric residual volumes in mechanically ventilated patients receiving enteral nutrition cannot be recommended.

Cerebrospinal fluid (CSF) leakage through dural sutures after craniotomy increases the risk of complications such as persistent CSF fistulas, meningitis, and subcutaneous, graft bone, or epidural infections. The effectiveness of fibrin glue for preventing CSF leakage through dural closure was investigated in 183 patients who underwent frontotemporal craniotomy for unruptured aneurysm. Fibrin glue was used in 138 patients, but not in the other 45. Computed tomography was used to evaluate postoperative extradural fluid collection as a minimal volume of low-density area. Postoperative computed tomography demonstrated transient increases in extradural fluid collection in 55 patients. However, none of these patients received a second surgery for dural repair. Fluid collection occurred in 19 of 45 patients (42%) in whom fibrin glue was not used, and in 36 of 138 patients (26%) in whom fibrin glue was used. The fibrin sealant on the dural suture was a significant factor in reducing the incidence of the fluid leakage (p < 0.05, chi-square test). Fibrin glue is a useful surgical tool for the prevention of postoperative extradural fluid collection through the dural sutures.

Background The primary objective of this study was to determine the efficiency of a pneumatic device in controlling cuff pressure (Pcuff) in patients intubated with polyurethane-cuffed tracheal tubes. Secondary objectives were to determine the impact of continuous control of Pcuff, and cuff shape on microaspiration of gastric contents. Methods Prospective randomized controlled study. All patients requiring intubation and mechanical ventilation ≥48 h were eligible. The first 32 patients were intubated with tapered polyurethane-cuffed, and the 32 following patients were intubated with cylindrical polyurethane-cuffed tracheal tubes. Patients randomly received 24 h of continuous control of Pcuff using a pneumatic device (Nosten®), and 24 h of routine care of Pcuff using a manometer. Target Pcuff was 25 cmH2O. Pcuff was continuously recorded, and pepsin was quantitatively measured in all tracheal aspirates during these periods. Results The pneumatic device was efficient in controlling Pcuff (med [IQ] 26 [24, 28] vs 22 [20, 28] cmH2O, during continuous control of Pcuff and routine care, respectively; p = 0.017). In addition, percentage of patients with underinflation (31% vs 68%) or overinflation (53% vs 100%) of tracheal cuff, and percentage of time spent with underinflation (0.9 [0, 17] vs 14% [4, 30]) or overinflation (0 [0, 2] vs 32% [9, 54]) were significantly (p cuff compared with routine care. No significant difference was found in microaspiration of gastric content between continuous control of Pcuff compared with routine care, or between patients intubated with tapered compared with cylindrical polyurethane-cuffed tracheal tubes. Conclusion The pneumatic device was efficient in controlling Pcuff in critically ill patients intubated with polyurethane-cuffed tracheal tubes. Trial registration The Australian New Zealand Clinical Trials Registry (NCT01351259)

Diagnostic lumbar puncture is essential to the diagnosis of central nervous system infections, subarachnoid haemorrhage and others neurological diseases. Myeloradicular involvement or life-threatening adverse events due to the procedure are rare, but less severe complications are more frequent. Post-lumbar puncture headache is the most common complication, by spinal fluid leakage due to delayed closure of a dural defect. Therefore, the development of fine needles, with differentiated atraumatic bevel, has contributed to minimize that problem. These generically called atraumatic needles cause less deformation of the dura mater then the Quincke® ones. So, why don't we use these atraumatic needles? A punção lombar é essencial para o diagnóstico de infecções do sistema nervoso central, hemorragia subaracnoídea e outras doenças neurológicas. O comprometimento mielorradicular ou efeitos adversos que envolvam risco de vida como consequência do procedimento são raros, mas complicações leves são mais frequentes. Cefaléia pós-punção lombar é a complicação mais comum, secundária a escoamento do líquido cefalorraquiano por fechamento tardio de uma lesão dural. Consequentemente, o desenvolvimento de agulhas finas, com bisel atraumático, tem contribuído para minimizar o problema. Estas agulhas, chamadas genericamente de atraumáticas, causam menos deformação da dura-mater que as agulhas tipo Quincke®. Então, porque não usar estas agulhas atraumáticas?

Background Current tracheal tubes (TTs) cannot guarantee a perfect seal against pulmonary aspiration of upper airway secretions. The purpose of this study was to investigate whether a gel layer between the tracheal tube with double cuffs (Double cuffs) prevents fluid leakage past TT cuffs. Methods In vitro fluid leakage tests were performed using the Double cuff with or without a gel layer between the two cuffs and four commercially available TTs (Euromedical Standard TT, Mallinckrodt Hi-Lo™, Microcuff, and Mallinckrodt TaperGuard™) when placed in artificial tracheas with three-different internal diameters (ID; 16, 20, and 22 mm). Blue-dyed water (5 ml) was placed above the cuff, and the extent of fluid leakage was observed for 48 h. Each test was repeated five times with new tubes at six different intracuff pressures (15, 20, 25, 30, 40, and 50 cm H2O). Results In all of the conventional TTs and the Double cuff without a gel layer, fluid leakage was observed even at clinically acceptable intracuff pressures (25–30 cm H2O). However, in the Double cuff with a gel layer, no fluid leakage was observed for 48 h at all intracuff pressures in three-different sized artificial tracheas. At an intracuff pressure of 20 cm H2O in a 20 mm ID trachea, the average volume of injected gel was 2.0 ml. After removal of the TT, the mean volume of the remaining gel in the trachea was 0.10 ml. Conclusions A prototype TT with gel-layered Double cuffs completely blocked fluid leakage past the cuffs for 48 h in a bench-top model. Clinical studies are required to determine whether this TT reduces the risk of ventilator-associated pneumonia.

Circumscribed choroidal hemangiomas are benign vascular tumors that can produce retinal exudation and fluid leakage.