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To address the frequent failure of hydraulic seals under high-pressure and high-flow continuous working conditions, optimizing the seal structure through intelligent optimization algorithms can improve performance. This paper proposes an improved intelligent optimization algorithm and finite element analysis to determine the optimal design parameters for the seal. Initially, a visual inspection and analysis of the failed Y-shaped seal revealed causes such as wear failure, damage failure, and leakage. Finite element analysis of the seal under actual working conditions confirmed the previous analysis. The study considered six control design parameters: lip base height, short-long lip length, short lip height, short lip angle, long lip angle, and lip base fillet radius. Using ANSYS, 50 parameter combinations were selected through Latin hypercube sampling for finite element simulation runs, with the maximum shear stress and maximum contact stress as optimization targets. A BP neural network was established and optimized using a genetic algorithm to design the unequal height Y-shaped seal structure based on NSGA-II, with optimization of the root chamfer to increase net pump backflow. The research results show a 7.29% reduction in maximum contact stress of the seal, a 21.4% decrease in maximum shear stress, and an increase of 0.066 mm3 in net pump backflow through chamfer optimization. The results indicate that this method effectively addresses design issues of seals in industrial applications. [ABSTRACT FROM AUTHOR]

Fluid leakage caused by debonding at the cement interfaces driven by low-temperature fluids is recognized as a significant challenge to wellbore integrity. Previous studies have primarily focused on casing/cement interface debonding, without thoroughly analyzing the simultaneous propagation of debonding fractures at the casing/cement interface and cement/formation interface. Furthermore, prior investigations have been conducted based on hydro-mechanical coupling analysis, neglecting the influence of injection fluid temperature on interface debonding. Therefore, this paper aims to reveal the debonding mechanism of the two cement interfaces using a coupled thermal–hydrological–mechanical (THM) modeling approach. Considering the effect of injected fluid temperature, a 3D numerical model of casing-cement-formation is developed for the simulation of the fluid-driven debonding based on the coupled pore pressure cohesive zone method. The influences of various factors including injection fluid temperature, flow rate, viscosity, casing pressure and cement Young's modulus on the cement sheath debonding are studied, and grey relational analysis is carried out on the influence degree of different factors. The results indicate that the fracture propagation pressure (FPP) is higher, and the fracture height is lower at the casing/cement interface compared to the cement/formation interface. When the fluid temperature is considered by the model, the FPP at the cement sheath interface is lower, and fracture initiation and propagation are more likely to occur. The results also demonstrate that higher fluid temperature, flow rate, viscosity and casing pressure increase the FPP and reduce the risk of cement sheath interface debonding. Casing pressure and fluid temperature exhibit a more prominent influence on FPP. The method can effectively predict the propagation of debonding failures at the cement sheath interface, and provide a foundation for the optimization of injection parameters. Highlights: This paper investigates the simultaneous propagation of the fluid-driven debonding of two cement interfaces considering the injected fluid temperature. A novel numerical model considering the fully coupled thermal–hydrological–mechanical processes is developed. Effects of injection fluid temperature, flow rate, viscosity, casing pressure and cement Young's modulus on the interface debonding are examined. A grey relational analysis is conducted to rank the influence degree of different factors. [ABSTRACT FROM AUTHOR]

In the routine maintenance of piping systems in power plants, maintenance management priorities are determined based on quantitative indicators, such as safety classification guidelines and probabilistic risk assessments, as well as qualitative metrics, such as supply reliability, operating experience, and work safety. In power plants, quantifying the level of maintenance criticality for areas that pose little risk to safety is difficult. Assuming damage to the piping system due to deterioration, the internal fluid flowing to the surrounding area may affect the functions of the peripheral equipment and work safety at the site. If the fluid temperature is high, the risk of burning increases. This study was aimed at quantifying the indicators of human burns that may pose a risk to work safety. Based on indicators related to the severity of human burns, we constructed an evaluation model using the results of fluid experiments and analysis of heat conduction in the skin to estimate the PBI, which in turn can be used to estimate the prognosis of burns. It was found that, especially under the condition for the evaluation of flashing, when a phase change occurs before and after a leak, the fluid diffusion range is large, and the fluid temperature is also high near the leak source. Such flow conditions can induce serious burns over a wide area. Based on the trends of the indicators related to human burns obtained in this study, we will construct a model to evaluate work safety risks in power plants using design information like temperature, pressure, and piping layout of the system.

To reduce the wear of lip seal of wide-speed hydraulic motor pump and prolong the service life, the lip compression is reduced and the non-contacting labyrinth seal is used as the front stage, forming a series combined dynamic seal (CDS). The reliability of CDS in the wide-speed range is verified by model experiment. Initially, the structure form and dimension of labyrinth seal with relatively small leakage and heat production were determined by model experiment. Then, by establishing the model of lip seal and simulating the static structure, the relationship between the compression and maximum contact pressure of the lip was obtained. Finally, using the CDS which is formed by combining the different lip seals with the selected labyrinth seal to carry out experiments, the leakage, temperature distribution and lip wear were obtained. The results show that trapezoidal tooth labyrinth seal (TTLS) has better sealing effect and less heat production. When the sealing clearance is 0.1 mm and 0.3 mm, it accounts for 0.11% and 0.32% of the rotor diameter, respectively. Under the same conditions, the smaller the proportion, the better the sealing effect, but the higher the heat production. With the increase of compression, the maximum sealing pressure first increases and then decreases. When the compression of the lip exceeds 0.1 mm, the CDS will not leak significantly in a wide-speed range, but the greater is the compression, the faster is the temperature rise in the closed cavity. Lip wear is positively correlated with pv and the wear decreases with the decrease of compression. [ABSTRACT FROM AUTHOR]

Background : Patients on peritoneal dialysis (PD) may develop PD-related complications that necessitate abdominal surgery. However, when to resume PD and how to prescribe PD fluid after surgery in pediatric patients are unknown. Methods: Patients on PD who underwent small-incision abdominal surgery between May 2006 and October 2021 were included in this retrospective observational study. The complications after surgery and characteristics of patients with PD fluid leakage were analyzed. Results: Thirty-four patients were included. They underwent 45 surgical procedures, including 23 inguinal hernia repairs, 17 PD catheter repositioning or omentectomy, and 5 others. The median time to resume PD was 1.0 (IQR, 1.0–3.0) days, and the median PD exchange volume at the initiation of PD after surgery was 25 (IQR, 20–30) ml/kg/cycle. PD-related peritonitis occurred in two patients after omentectomy and one after inguinal hernia repair. There was no PD fluid leakage or hernia recurrence among the 22 patients who had a hernia repair. Peritoneal leakage occurred in 3 of the 17 patients who had PD catheter repositioning or an omentectomy and was treated conservatively. No patients who resumed PD 3 days after small-incision abdominal surgery with less than half of PD volume had fluid leakage. Conclusions: Our findings demonstrated that PD could be resumed within 48 h of inguinal hernia repair with no PD fluid leakage or hernia recurrence in pediatric patients. In addition, resuming PD 3 days after a laparoscopic procedure with less than half of the usual dialysate volume might reduce the risk of PD fluid leakage. [ABSTRACT FROM AUTHOR]

Fluid viscous dampers (FVDs) are the key energy dissipation devices for long-span suspension bridges, and their leakage poses a threat to the stable and reliable operation of bridge restraint systems. Therefore, this paper proposed an FVD fluid leakage diagnosis method based on girder longitudinal displacement monitoring data. First, the longitudinal vibration equation of the main girder under traffic loads was derived to reveal the displacement characteristic of girder-end motion. On this basis, considering that different displacement components under traffic loads are coupled and transient analysis directly utilizing traffic loads as the excitation is complicated and inefficient, an analysis framework focusing on the influence mechanism of FVD leakage on quasi-static displacement was established. Second, an equivalent mechanical model for simulating the hysteresis relationship of leaked FVD was proposed and verified. Then, the influence of variations in the location, number, leakage level and parameters of the leaked FVD on the quasi-static displacement was studied. Third, the equivalent traffic load (ETL) indicator was constructed to characterize the traffic volume. Furthermore, a quasi-static cumulative displacement and ETL correlation model, which can effectively eliminate the interference of traffic flow variations, was proposed for the leakage diagnosis of FVD. Finally, the proposed method was verified by real suspension bridge monitoring data. The results demonstrated that the proposed method can effectively detect a mild increase in the girder-end cumulative displacement due to FVD fluid leakage. • Proposed and validated an equivalent model for simulating the hysteresis relationship of leaked FVD. • The influence of leaked FVD locations, numbers, leakage levels and parameters on vehicle-induced GECD was revealed. • An online diagnosis method was established to realize the condition monitoring of FVD leakage in operation. • The effectiveness is verified by case study of an actual in-service suspension bridge. [ABSTRACT FROM AUTHOR]

Interfacial surface roughness can result in fluid leakage of seals, and in the design of seals it is standard to give an upper limit for the surface root-mean-square (rms) roughness amplitude h rms . However, h rms is determined mainly by the long-wavelength roughness, which is (nearly) irrelevant for the sealing. I discuss the parameters which determine the leakage of seals, and present results for static rubber seals with circular cross-section (like rubber O-rings). I also study the influence of the fluid pressure on the interfacial surface separation and the leakrate. [ABSTRACT FROM AUTHOR]

Abstract Background Dengue fever prevalence is rising globally and it causes significant morbidity and mortality. Fluid extravasation during the critical phase of dengue haemorrhagic fever (DHF) leads to shock, multi-organ failure and death if not resuscitated appropriately with fluids. The mainstay of management is judicious fluid replacement using a guideline based, calculated fluid quota of maintenance (M) fluid plus 5% deficit (M + 5% deficit) to prevent organ hypoperfusion. Methods We conducted an observational follow-up study in Sri Lanka from January–July 2017 to identify the fluid requirements of DHF patients and to identify whether features of fluid overload are present in patients who exceeded the fluid quota. Patients who developed DHF following admission to the place of study, were recruited and the amount of fluid received during the critical phase was documented. Results A total of 115 DHF patients with a mean age of 30.3 (SD 12.2) years were recruited to the study. There were 65 (56.5%) males and the mean fluid requirement was 5279.7 ml (SD 735) over the 48 h. Majority of the study participants (n = 80, 69.6%) received fluid in excess of the recommended maintenance + 5% deficit and this group had higher body mass index (22.75 vs 20.76, p0.03) and a lower white cell count at the onset of the critical phase (3.22 × 103 vs 4.78 × 103, p

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A hydraulic cylinder is a mechanical actuator that is widely used in different industries such as construction, manufacturing, aerospace, and offshore oil and gas. Seal wear in hydraulic cylinders results in hydraulic fluid leakage or contamination of the hydraulic fluid. Untimely, failure of a hydraulic cylinder increases the maintenance cost and reduces productivity. Therefore, condition monitoring of the hydraulic cylinder is necessary to understand the current state of equipment. In the literature, there have been numerous documented attempts to perform condition monitoring of hydraulic cylinders using different methods, based on fluid properties, pressure, vibration, and acoustic emission. However, there have been limited attempts to present a state-of-the-art review of condition monitoring of hydraulic cylinders. This article presents an overview of the methods used for the condition monitoring of hydraulic cylinders, including the detection of different failure modes using different sensors, the separability of fault conditions using sensor-based features, and the ability to pick up incipient faults by sensor-based features. This information is required for new readers in this area of expertise. This article summarizes different condition monitoring methods that have been used from its early implementation to very recent dates, aiming at clarifying recent advances and identifying challenges in the research of the condition monitoring of hydraulic cylinders. It is anticipated that the information presented in this article will be beneficial for new researchers and provide directions for future research in the area of condition monitoring of hydraulic cylinders. [ABSTRACT FROM AUTHOR]

Background: Dengue fever prevalence is rising globally and it causes significant morbidity and mortality. Fluid extravasation during the critical phase of dengue haemorrhagic fever (DHF) leads to shock, multi-organ failure and death if not resuscitated appropriately with fluids. The mainstay of management is judicious fluid replacement using a guideline based, calculated fluid quota of maintenance (M) fluid plus 5% deficit (M +  5% deficit) to prevent organ hypoperfusion.Methods: We conducted an observational follow-up study in Sri Lanka from January-July 2017 to identify the fluid requirements of DHF patients and to identify whether features of fluid overload are present in patients who exceeded the fluid quota. Patients who developed DHF following admission to the place of study, were recruited and the amount of fluid received during the critical phase was documented.Results: A total of 115 DHF patients with a mean age of 30.3 (SD 12.2) years were recruited to the study. There were 65 (56.5%) males and the mean fluid requirement was 5279.7 ml (SD 735) over the 48 h. Majority of the study participants (n = 80, 69.6%) received fluid in excess of the recommended maintenance + 5% deficit and this group had higher body mass index (22.75 vs 20.76, p0.03) and a lower white cell count at the onset of the critical phase (3.22 × 103 vs 4.78 × 103, p < 0.001). The highest fluid requirement was seen within the first 12 and 24 h of the critical phase in patients requiring fluid M +  5%-7.5% deficit and ≥ M +  7.5% deficit respectively. Patients exceeding M + 5% deficit had narrow pulse pressure and hypotension compared to the rest. DHF grades III and IV were seen exclusively in patients exceeding the fluid quota indicating higher amount of fluid was given for resuscitation. Fluid overload was detected in 14 (12.1%) patients and diuretic therapy was required in 6 (5.2%) patients.Conclusions: The majority of patients received fluid in excess of the recommended quota and this group represents patients with narrow pulse pressure and hypotension. Although, fluid overload was infrequent in the study population, clinicians should be cautious when administering fluid in excess of M +  7.5% deficit. [ABSTRACT FROM AUTHOR]

Abstract The indwelling pleural catheter (IPC) is an established treatment for recurrent pleural effusion. Fluid leakage through the IPC insertion tract has been reported, but its occurrence is only limited to a short period after the procedure. Besides, the drainage efficacy of IPC may be limited by the presence of loculation in the pleural space, especially when intrapleural fibrinolytic is contraindicated. We report a case of fluid leakage through the healed entry site of IPC due to high pressure built from undrained pleural fluid locules, which was successfully treated with an additional drain targeting the largest undrained locule.

In modern mobile power tools of domestic and foreign production, the torque from the engine to the working mechanisms is transferred, as a rule, by hydrostatic drives consisting of regulated and unregulated axial-plunger hydrounits. Their technical condition directly affects the performance of machinery in general. The analysis of the operability and longevity of controlled axial-plunger hydraulic units showed that in the pre-repair operation period the share of their failures is about 20 % of the total number of machine failures. According to scientific and technical sources, the average overhaul life of the repaired controlled axial-plunger hydrounits of the 313.3 series under actual operation does not exceed 60 % of the resource of the new product. The most vulnerable hydraulic drive units are the axial-plunger motor and pump, which include precision parts and make up more than 90 % of the cost of the entire drive. If the hydraulic drive fails and the malfunction can not be repaired directly in the operating conditions, the above mentioned units are sent to specialized enterprises for repair. Usually, because of the lack of diagnostic equipment, both at the operator enterprises and at repair enterprises both units are sent for repair without preliminary diagnosis. Repair companies explain the need to send both of units for repair as they have the same residual life. The results of our studies show the absence of such a pattern. At the repair enterprises, the repair is not carried out for the same reason — the lack of diagnostic equipment. Due to this, the two units sent for repair are subjected to complete disassembly, defects identification and repair. The available research results show that in more than 40 % of cases, the units require no repair. The purpose of the work is to develop a stand and a method for assessing the technical condition of hydraulic power units for mobile power equipment, to increase the functional reliability and efficiency of maintenance, to prevent failures during operation of the hydraulic drive and to ensure the prediction of the residual life of aggregates at specified operating intervals.

Magnetorheological (MR) dampers are common methods that are used to mitigate cable vibrations with high effectiveness. Under the long-term effect of external loads and harsh environment, MR dampers will probably suffer from various durability problems, especially fluid leakage. Hence, accurate modeling and evaluation of the effect of fluid leakage of MR dampers are of great significance for bridge maintenance. This paper will investigate the mechanical behavior of MR dampers with fluid leakage after long-term operation and will evaluate their residual performance for cable vibration control. First, three MR dampers with fluid leakage will be selected from a real bridge, followed by a laboratory test to illustrate their damping force characteristics. Based on the experimental results, a theoretical model will be proposed to predict the mechanical behavior of the leaked dampers. A parametric analysis will then be conducted to show the effect of fluid leakage on the damping capacity. Then, one full-scale cable will be idealized as a taut string and the equation of motion for the cable-leaked MR damper system will be formulated. Additional modal damping provided by the MR damper will be determined numerically. The results show that fluid leakage could cause considerable slipping in the damping force. This slipping could lead to a remarkable reduction of the achieved additional modal ratios for the cables. The results of this paper could be of practical significance for the assessment of cable dampers performance and their maintenance on real bridges. [ABSTRACT FROM AUTHOR]

The indwelling pleural catheter (IPC) is an established treatment for recurrent pleural effusion. Fluid leakage through the IPC insertion tract has been reported, but its occurrence is only limited to a short period after the procedure. Besides, the drainage efficacy of IPC may be limited by the presence of loculation in the pleural space, especially when intrapleural fibrinolytic is contraindicated. We report a case of fluid leakage through the healed entry site of IPC due to high pressure built from undrained pleural fluid locules, which was successfully treated with an additional drain targeting the largest undrained locule. [ABSTRACT FROM AUTHOR]

Background: Premature rupture of membranes occurring in previable midtrimester patients is associated with perinatal mortality, and optimal therapeutic methods are yet to be established.Objective: This study's objective was to investigate whether an elastomeric sealant, which has been used as a hemostatic agent for arterial anastomosis, could plug the uterine endocervical canal to prevent leakage of intrauterine fluid in an ex vivo model.Methods: The elastomeric sealant or fibrin glue was applied to the cervix of uteri removed for benign gynecological disease (n = 4). Normal saline was administered into the ex vivo uterine cavity through a catheter using a pressure infusion bag. Intrauterine pressure was measured using a digital pressure gauge, and the pressure at which normal saline started leaking out of the uterine cervix was compared between both the sealants.Results: No fluid leakage was observed with the elastomeric sealant until the pressure exceeded 20 kPa (150 mmHg), while the leakage onset pressure with fibrin sealant was 6.6 ± 1.8 kPa (50 ± 14 mmHg). The threshold leak pressure where the onset of liquid flow was initiated was significantly different between both the sealants (p < .0001).Conclusions: Intracervical elastomeric sealant exhibited powerful fluid leakage prevention in an ex vivo model. The sealant would have potential to prevent the leakage of amniotic fluid in pregnancies with previable premature rupture of membranes. [ABSTRACT FROM AUTHOR]

Hydrocarbon discoveries in recent years in the Upper Miocene of the Yinggehai Basin show differences in overpressure magnitude, gas and mineral components. Overpressure close to or reaching the leakage threshold has induced high system openness for one field, but the overpressure of another field remains to be safely closed. A new vision to investigate the interplay between the system openness and the gas chemical and mineralogical features were conducted. The gas components in the high openness system are rich in high maturity hydrocarbons and inorganic CO 2 , which both have heavier carbon isotopes. Low maturity gases with lighter carbon isotopes are dominant in the low openness system. The abnormal carbon isotope ratio between iso-butane and n-butane in the high openness system confirms that early low maturity leakage has generated abnormal compositional and isotopic fractionation. Although the sedimentation process was uniform in the two systems, the high openness system has rare K-feldspar grains and chlorite, but it is rich in illite/smectite mixed layers (I/S). Precipitation is characterized by ankerite and kaolinite in the high openness system, whereas the low openness system primarily consists of calcite. The strong dissolution of K-feldspar grains and chlorite should have released abundant potassium and silicon. The high abundances of I/S and kaolinite, which are both sensitive to potassium and the rarity of quartz overgrowths in the high openness system, imply that the leakage of potassium/silicon from the sandstones has induced a mass imbalance between dissolution and precipitation. Even the sandstone porosity was slightly increased by the mass imbalance in the high openness system. The risk of hydrocarbon expulsion during brine leakage cannot be ignored. [ABSTRACT FROM AUTHOR]

The potential for fluid leakage from sub-surface reservoirs has important implications for CO2 storage, hydrocarbon reservoirs and water resources. Understanding the genesis, morphology, fluid flow mechanisms and extent of fluid escape from reservoirs allows for better risking of geological resources and storage potential. Here we describe in detail the structures of fluid escape pipes from the Loyal Field, observed from a 3D full and partial stack seismic dataset. The seismic imagery suggests that the fluid escape pipes are rooted at least in the main Paleocene reservoir and by-pass the reservoir seal to cross the post Lista Formation overburden up to the intra-Neogene units. The pipes extend for a few hundred meters to a few kilometres and show varying shape and structure from blow-out structures to incipient mud volcanoes. A detailed analysis of the seismic characteristics observed both from main baseline and partial stack data allows a division of the pipes into two families: (1) seeps and pipes following structural discontinuities and (2) pipes unrelated to the pre-existing structural features. The pipes internal seismic response, the reflector termination of the main conduits and the distribution of stacked bright reflectors suggest an upward migration mechanism (during pipe birth and development), requiring a cyclic switching from non-Darcy hydrofracturing (during overpressure) to Darcy flow lateral migration (during low-pressure stage). [ABSTRACT FROM AUTHOR]

Gold-patterned glass substrates sealed to a PDMS fluidic layer is an architecture widely employed in microfluidic devices. The plasma bonding method is commonly used but presents the disadvantage of being ineffective on gold surfaces, creating a sealing weakness where solution leakage can be a problem. Frequently, alternative approaches to sealing include additional patterned layers that often require expensive cleanroom time. Here we demonstrate a sealing method involving carboxyl-terminated and amine-terminated silanes appropriate for PDMS-based device fabrication with patterned gold/glass surfaces. This cleanroom-free methodology improves solution leak pressure 37-fold compared to the standard plasma bonding technique on these patterned substrates. This bonding strategy is demonstrated in a proof-of-concept electrochemical cell enclosed in a PDMS chamber. An electrochemical method for preparing a clean and electroanalytically useful gold surface in the PDMS device is detailed. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

An experimental and finite element study on water leakage through reinforced concrete structural elements is presented in the paper. A macroscopic probabilistic approach is used to predict structural transfer properties evolution induced by concrete cracking. In this model, material heterogeneity is taken into account by randomly distributing the mechanical elementary properties (tensile strength, cracking energy) over the computational mesh. Each finite element is considered as representative of a volume of heterogeneous material, whose mechanical behavior depends on its own volume. The parameters of the statistical distributions defining the elementary mechanical properties thus vary over the computational mesh element-by-element according to experimentally validated constitutive laws. Under a weak hydro-mechanical coupling assumption, the model considers that the mechanical cracking of a finite element induces loss of isotropy of its own permeability tensor. So, at the finite element level, the localized crack flow is smeared over the elementary volume. Its contribution is computed according to an experimentally enhanced parallel plates model. An experimental test, which studies the real-time water transmissivity evolution of reinforced concrete tie-specimens under uniaxial tensile loading, is numerically simulated. Constitutive hydro-mechanical parameters were calibrated in previous works for a given concrete formulation. So, in order to avoid of any adjustments in the model parameters, the reference experimental test was performed with the same concrete formulation as in previous phases of the research. Numerical results evidence that, once steel-concrete interface is properly treated, a probabilistic approach can lead to proper predictions of cracking and its effect on fluid leakage. [ABSTRACT FROM AUTHOR]

Background: Liver involvement in acute dengue infection is frequently observed and sometimes leads to acute liver failure, with fatal outcomes. Many factors are thought to contribute to liver dysfunction, including hypoxic injury due to decreased perfusion, direct damage by the virus and immune mediated injury. In this study, we sought to identify the pattern in the change in liver enzymes throughout the illness and its association with the degree of viraemia, onset and extent of plasma leakage and inflammatory mediators.Methods: Serial daily blood samples were obtained from 55 adult patients with acute dengue from the time of admission to discharge and the liver function tests, viral loads and cytokines were assessed. The onset and extent of fluid leakage was measured by daily ultrasound examinations and all clinical and laboratory features were serially recorded.Results: Aspartate transaminase (AST), alanine transaminase (ALT) and gamma glutamyl transferase (GGT) levels were elevated in patients with dengue infection throughout the illness. The highest AST levels were seen on day 6 of illness and both AST and GGT levels were significantly higher in patients with severe dengue (SD), when compared to those with non-severe dengue (NSD) on day 5 and 6 of illness. Three patients with SD had AST and ALT values of >1000/IU in the absence of any fluid leakage or a rise in the haematocrit (≥20 %). The peak of the AST levels and the lowest serum albumin levels were seen 24 h before the maximum fluid leakage and 24 h after the peak in viraemia. Both serum IL-10 and IL-17 levels were elevated during early illness and were significantly higher in those with SD when compared to NSD.Conclusion: Dengue associated liver injury appears to peak around day 6 and 7. Therefore, liver function tests done at earlier dates might not reflect the extent of liver involvement in acute infection. Since severe liver involvement can occur in the absence of fluid leakage, after the peak viraemia, and since it is associated with high IL-17 and IL-10 levels, possible immune mechanisms leading to hepatic damage should be investigated. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Purpose: 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,0.005), and endoscopy of porcine eyes showed that vitreous incarceration was significantly greater with 23-gauge (P,0.05) and 27-gauge (P,0.05) non-valved cannulas. External observation of rabbit eyes showed vitreous prolapse through non-valved, but not valved, cannulas. Conclusion: Valved cannulas surpassed non-valved cannulas in maintaining IOP, preventing fluid leakage, and reducing vitreous incarceration during simulated vitrectomy. [ABSTRACT FROM AUTHOR]

As an index of maintaining low fuel consumption, the digging force of an excavator is affected fully by the performance of the hydraulic actuators including boom cylinder, stick cylinder, and bucket cylinder. The seals are used widely in a fluid power system to prevent fluid leakage. However, wear induces changes in the diameter of the seal's cross-section area, having an effect on the sealing capability of seals. This article proposes a model for performance degradation induced by wear of a hydraulic actuator of an excavator. The model in this article describes the physical process of performance degradation of a hydraulic actuator by analyzing piston response when wear occurs. The model includes a dynamic model of a hydraulic actuator, a model of squeezing stress and deformation of a compressed elastomeric O-ring seal, a wear model of a seal, and a leak rate model. These models can be used for deducing the laws of performance degradation of a hydraulic actuator of an excavator and for predicting the useful life of a key component such as the seal. Finally, based on the established model, simulation results of a hydraulic actuator’s response are provided. [ABSTRACT FROM PUBLISHER]