Fluid Outflow Research Articles

Intraoperative measurement of intraventricular pressure in dogs with communicating internal hydrocephalus.

Collapse of the lateral cerebral ventricles after ventriculo-peritoneal drainage is a fatal complication in dogs with internal hydrocephalus. It occurs due to excessive outflow of cerebrospinal fluid into the peritoneal cavity (overshunting). In most shunt systems, one-way valves with different pressure settings regulate flow into the distal catheter to avoid overshunting. The rationale for the choice of an appropriate opening pressure is a setting at the upper limit of normal intracranial pressure in dogs. However, physiological intraventricular pressure in normal dogs vary between 5 and 12 mm Hg. Furthermore, we hypothesise that intraventricular pressure in hydrocephalic dogs might differ from pressure in normal dogs and we also consider that normotensive hydrocephalus exists in dogs, as in humans. In order to evaluate intraventricular pressure in hydrocephalic dogs, twenty-three client owned dogs with newly diagnosed communicating internal hydrocephalus were examined before implantation of a ventriculo-peritoneal shunt using a single use piezo-resistive strain-gauge sensor (MicroSensor ICP probe). Ventricular volume and brain volume were measured before surgery, based on magnetic resonance images. Total ventricular volume was calculated and expressed in relation to the total volume of the brain, including the cerebrum, cerebellum, and brainstem (ventricle-brain index). Multiple logistic regression analysis was performed to assess the influence of the covariates “age”, “gender”, “duration of clinical signs”, “body weight”, and “ventricle-brain index” on intraventricular pressure. The mean cerebrospinal fluid pressure in the hydrocephalic dogs was 8.8 mm Hg (standard deviation 4.22), ranging from 3–18 mm Hg. The covariates “age”, (P = 0.782), “gender” (P = 0.162), “body weight”, (P = 0.065), or ventricle-brain index (P = 0.27)” were not correlated with intraventricular pressure. The duration of clinical signs before surgery, however, was correlated with intraventricular pressure (P< 0.0001). Dogs with internal hydrocephalus do not necessarily have increased intraventricular pressure. Normotensive communicating hydrocephalus exists in dogs.

A mathematical model demonstrating the role of interstitial fluid flow on the clearance and accumulation of amyloid β in the brain

A system of partial differential equations is developed to describe the formation and clearance of amyloid β (Aβ) and the subsequent buildup of Aβ plaques in the brain, which are associated with Alzheimer’s disease. The Aβ related proteins are divided into five distinct categories depending on their size. In addition to enzymatic degradation, the clearance via diffusion and the outflow of interstitial fluid (ISF) into the surrounding cerebral spinal fluid (CSF) are considered. Treating the brain tissue as a porous medium, a simplified two-dimensional circular geometry is assumed for the transverse section of the brain leading to a nonlinear, coupled system of PDEs. Asymptotic analysis is carried out for the steady states of the spatially homogeneous system in the vanishingly small limit of Aβ clearance rate. The PDE model is studied numerically for two cases, a spherically symmetric case and a more realistic 2D asymmetric case, allowing for non-uniform boundary conditions. Our investigations demonstrate that ISF advection is a key component in reproducing the clinically observed accumulation of plaques on the outer boundaries. Furthermore, ISF circulation serves to enhance Aβ clearance over diffusion alone and that non-uniformities in ISF drainage into the CSF can lead to local clustering of plaques. Analysis of the model also demonstrates that plaque formation does not directly correspond to the high presence of toxic oligomers.

Clinical and Immunological Evaluation of the Effectiveness of Non-Penetrating Deep Sclerectomy in the Early Postoperative Period

Today the mechanisms of pathological scarring and inconsistency of the intraocular fluid outflow pathways after nonpenetrating deep sclerectomy (NPDS), reducing its effectiveness, have not yet been determined. There is no systematic information about the regulatory role of cytokine TGF-β and MMP-9 in the mechanisms of formation of the newly created intraocular fluid outflow pathways.Aim: to assess changes in the clinical and immunological status of patients with open-angle glaucoma after NPDS in the early postoperative period.Methods. A prospective examination of 26 patients with open-angle glaucoma before and in 1 month after NPDS with determination of concentration of TGF-β and MMP-9 in tear humor. One month after NPDS, all patients were divided into two groups depending on the effect of the operation achieved according to the developed criteria.Results. Before the operation, tears TGF-β values in group 1 exceeded baseline values of group 2 by 1.4 times, the initial content of MMP-9 in tears in both groups was comparable. After the operation, in group 1, a moderate increase in the concentration of tears TGF-β by 1.3 times and a significant increase in the concentration of tears MMP-9 in 4.6 times compared with baseline values were revealed. In patients of group 2, after NPDS, there was a significant increase in the concentration of tears TGF-β, on average, 2.4 times relative to preoperative values, the content of MMP-9 did not significantly change.Conclusion. 1 month after NPDS, an imbalance in the concentration of TGF-β and MMP-9 in tears was detected in patients of the two groups that have fundamental clinical differences in the hypotensive effect and the formation of postoperative intraocular fluid outflow pathways.

Predictors of Ventriculoperitoneal shunting following Subarachnoid Hemorrhage treated with External Ventricular Drainage.

Aneurysmal subarachnoid hemorrhage (aSAH) is commonly associated with hydrocephalus due to subarachnoid hemorrhage blood products obstructing cerebrospinal fluid outflow. Hydrocephalus after aSAH is routinely managed with temporary external ventricular drainage (EVD) followed by standard EVD weaning protocols, which determine the need for ventriculoperitoneal shunting (VPS). We sought to investigate aSAH patients who initially passed EVD weaning trials and had EVD removal, but later presented with recurrent, delayed, symptomatic hydrocephalus requiring a VPS. We conducted a retrospective review of all patients at our tertiary care medical center who presented with aSAH, requiring an EVD. We analyzed variables associated with ultimate VPS dependency during hospitalization. We reviewed 489 patients with aSAH over a 6-year period (2008-2014). One hundred and thirty-eight (28.2%) developed hydrocephalus requiring a temporary EVD. Forty-four (31.9%) of these patients died or had withdrawal of care during admission, and were excluded from final analysis. Of the remaining 94 patients, 29 (30.9%) failed their clamp trial and required VPS. Sixty-five (69.1%) patients passed their clamp trial and were discharged without a VPS. However, 10 (15.4%) of these patients developed delayed hydrocephalus after discharge and ultimately required VPS [mean (range) days after discharge, 97.2 (35-188)]. Compared to early VPS, the delayed VPS group had a higher incidence of symptomatic vasospasm (90.0% vs 51.7%; P = 0.03). When comparing patients discharged from the hospital without VPS, delayed VPS patients also had higher 6- and 12-month mortality (P = 0.02) and longer EVD clamp trials (P < 0.01) than patients who never required VPS but had an EVD during hospitalization. Delayed hydrocephalus occurred in only 7.8% of patients who passed the initial EVD clamp trial, compared to 14.3% who failed the initial trial and 80.0% who failed 2 or more trials. Patients who failed their initial or subsequent EVD clamp trials had a small, but increased risk of developing delayed hydrocephalus ultimately requiring VPS. Additionally, the majority of patients who presented with delayed hydrocephalus also suffered symptomatic vasospasm. These associations should be further explored and validated in a larger prospective study.

Fluid migrations at the Krasny Yar methane seep of Lake Baikal according to geochemical data

Sediments of the deep water Krasny Yar methane seep area of Lake Baikal contain channels of 1 cm in diameter and up to a depth of 150 cm that have a high water content and are characterized by higher oxidized and reduced conditions than the surrounding sediment. New data of lithological and geochemical studies, including the full anionic and cationic composition of pore waters, indicate that chemical flow at the sediment surface of the seep is heterogeneous in space with both areas of inflow of fluids and areas with outflow of fluids. We suggest that much of this flow is modulated by more complex hydrological processes that may include aqueous pumping driven by gas expulsion- and changes in the permeability of the conduits due to gas hydrate formation and dissociation. We discuss the seep output fluid chemistry and heat flow in relation to the above hydrological processes and propose a seep model where fluid and gas migrations act at different spatial scales partly favored by hydrate accumulation and the fresh water conditions of Lake Baikal.

Drainage tube hole suture improvement: Removal-free stitches.

Surgical method improvements aim to optimize the patient experience. The problem of healing of the drainage tube hole has not received attention and is of concern because it can plague patient recovery. In this article we report on how we have improved the method of suturing the drainage tube hole and explore the safety and effectiveness of this method. Between December 2017 to August 2018, 102 patients underwent thoracoscopic lung resection (single port or single utility port) using different methods of suturing drainage tube holes. The intervention group received improved methods with subcuticular and intradermal suture and removal‐free stitches, whilst the control group received a conventional mattress suture and fixed chest tube. A preset line was left to tie knots and close the hole after the removal of the chest tube. The stitches were removed 7–12 days after surgery. The baseline clinical features of the patients were subsequently analyzed. The objective and subjective conditions of scars were evaluated using the Vancouver Scar Scale (VSS) and the Patient and Observer Scar Assessment Scale (POSAS) at one month after surgery. The intervention group (n = 71) and control group (n = 31) had balanced baseline clinical characteristics. There were no significant differences between the two groups in terms of three‐day postoperative pain and postoperative hospital stay. In the intervention group, three patients (4.23%) had wound splitting that required re‐suturing, which was better than five patients (16.13%) in the control group (P < 0.05). The incidence of pleural fluid outflow, wound infection, post‐removal pneumothorax, chest tube prolapse and incisional hernia were not different between the two groups. We conclude that the objective and subjective evaluation results of scars were significantly different between the two groups (P < 0.05), and the experimental group was superior to the control group. A balanced result between aesthetic appearance and safety as regards video‐assisted thoracic surgery can be achieved through the chest tube hole improved suture method. This method also improves the patient's recovery experience.

PSVII-16 Galactosylated chitosan-oligosaccharides have anti-adhesive effect against enterotoxigenic Escherichia coli in piglets

Abstract Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrhea in piglets. In vitro, high molecular weight β-galactosylated chitosan-oligosaccharides (Gal-COS) had strong anti-adhesive activity against ETEC-expressing K88 fimbriae (ETEC K88) binding to porcine erythrocytes. This study assessed the effects of Gal-COS differing in structure on anti-adhesive properties against ETEC in a small intestinal segment perfusion (SISP) model in 8 piglets (BW 10 kg; 5-wk old). With 10 jejunal segments in each pig, 5 segments were infected with ETEC K88, and the other 5 segments were infused with saline (non-ETEC). Every 2 paired segments (ETEC or non-ETEC) from the same pig were treated for 8 h with 64 ml of 10 g L-1 of one of the following test products: 1) α-Gal-COS; 2) β-Gal-COS; 3) exopolysaccharides produced by Lactobacillus reuteri; and 4) raffinose in a double 4 × 4 Latin square with a saline control. Infection by ETEC K88 was verified by quantitative PCR. Net fluid loss was calculated as difference of fluid loss between ETEC segment and its paired non-ETEC segment. Data were analyzed using the mixed model with segment and test product as fixed effects, and pig as random effect. Number of eubacterial rRNA genes was 10-fold greater (P &lt; 0.001) in ETEC segments than non-ETEC segments, indicating that ETEC K88 accounted for &gt; 90% of bacterial gene counts. Test product did not affect (P &gt; 0.10) the number of ETEC bacteria in the outflow fluid. Furthermore, net fluid loss caused by ETEC tended (P = 0.08) to be decreased by β-Gal-COS compared to all other treatments. In conclusion, the in vivo SISP model confirmed that Gal-COS had anti-diarrheal effects, indicating that β-Gal-COS is a potential feed additive to reduce the ETEC-induced diarrhea in piglets.

Validation of a mathematical model for understanding intracranial pressure curve morphology

The physiology underlying the intracranial pressure (ICP) curve morphology is not fully understood. Recent research has suggested that the morphology could be dependent on arterial cerebral inflow and the physiological and pathophysiological properties of the intracranial cavity. If understood, the ICP curve could provide information about the patient’s cerebrovascular state important in individualizing treatment in neuro intensive care patients. A mathematical model based on known physiological properties of the intracranial compartment was created. Clinical measurements from ten neuro intensive care patients in whom intracranial arterial blood inflow, venous blood outflow and cerebrospinal fluid flow over the foramen magnum had been measured with phase contrast MRI, concomitant with ICP measurements were used to validate the model. In nine patients the mathematical model was able to create an ICP curve mimicking the measured by using arterial intracranial inflow and adjusting physiological parameters of the model. The venous outflow and cerebrospinal fluid (CSF) flow over the foramen magnum predicted by the model were within physiologically reasonable limits and in most cases followed the MRI measured values in close adjunct. The presented model could produce an ICP curve in close resemblance of the in vivo measured curves. This strengthens the hypothesis that the ICP curve is shaped by the arterial intracranial inflow and the physiological properties of the intracranial cavity.

Electrocautery in arthroscopic surgery: intra-articular fluid temperatures above 43°C cause potential tissue damage.

The use of electrocautery during arthroscopy may heat intra-articular saline and subsequently damage intra- and extra-articular tissue. Newer electrocautery devices have the ability to measure the outflow fluid temperature and switch off before reaching a certain threshold; however, the scientific evidence establishing these temperature thresholds' potential for inadvertent damage is lacking. The aim of this study was to analyse current available literature on temperature thresholds for tissue damage after exposure to heated fluid and provide a recommendation for the maximum temperature of intra-articular fluid to prevent tissue damage. In February 2018, a systematic literature review was performed using the MEDLINE/PubMed and Embase databases. Inclusion was limited to studies investigating temperature thresholds for thermal damage to at least one of the tissues of interest: skin, bone, cartilage, soft tissues, and nerves. Studies not reporting specific temperature thresholds for thermal damage were excluded. Twenty articles were selected for the final evaluation and data extraction. Varying temperature thresholds, based on the lowest reported temperature causing tissue damage, were found for the different tissues of interest: 44°C for dermal tissues, between 47 and 50°C for bony tissues, 50°C for cartilage, between 43 and 55°C for soft tissues, and 43°C for nerves. Based on the current literature, a temperature threshold for intra-articular fluid of 43°C during an arthroscopic procedure is recommended to prevent tissue damage. Higher temperatures may cause damage to surrounding intra- and extra-articular tissues. The threshold for irreversible damage is likely to be higher. In clinical practise, one should be aware of possible heating of intra-articular fluid when using electrocautery and related risk of tissue damage. III.

Scleral and conjunctival features in patients with rhegmatogenous retinal detachment undergoing scleral buckling: an anterior segment optical coherence tomography and in vivo confocal microscopy study.

To investigate the scleral and conjunctival features in patients with rhegmatogenous retinal detachment (RRD) undergoing scleral buckling (SB), using anterior segment optical coherence tomography (AS-OCT) and in vivo confocal microscopy (IVCM). Twenty RRD eyes were consecutively enrolled. AS-OCT was performed at RRD diagnosis (RRD-D) and day 1, week 1, month 1 and month 6 after SB to evaluate the sclera, in the affected and unaffected quadrants (AQ, UQ). IVCM was performed at RRD-D, and at month 1 and month 6, to evaluate the conjunctiva in AQ and UQ. The main outcomes were as follows: mean intra-scleral hypo-reflective spaces area (MIHSA) at AS-OCT; mean density and area of microcysts (MMD, MMA) at IVCM; and intra-ocular pressure (IOP). The relations between MIHSA, MMA, MMD and IOP were evaluated. Rhegmatogenous retinal detachment- diagnosis (RRD-D) overall-mean intra-scleral hypo-reflective spaces (MISHA), -MMD and -MMA were significantly higher in affected eye (AE) compared with UE (p<0.05) and in AQ compared with UQ (p<0.05). After SB, overall-, AQ- and UQ-MISHA further increased (p<0.05), whereas overall-MMD and -MMA did not change. At all follow-up, AQ and UQ parameters did not show significant differences between them. RRD-D IOP was 14.3±2.8 and 15.5±2.7mmHg in the AE and UE, respectively (p<0.05). After SB, week-1, month-1 and -6 IOP was significantly lower than RRD-D (p<0.05). Rhegmatogenous retinal detachment- diagnosis (RRD-D), 1- and 6-month overall and AQ-MISHA and AQ-MMD negatively correlated with IOP (p<0.05). Rhegmatogenous retinal detachment (RRD) and SB induced scleral and conjunctival changes that suggested an activation of fluid outflow through the entire unconventional aqueous humour pathway; these modifications may in part account for the relative hypotony after RRD and SB.

Impaired Peripheral Lymphatic Function and Cerebrospinal Fluid Outflow in a Mouse Model of Alzheimer's Disease.

Cerebrospinal fluid (CSF) outflow from the brain occurs through absorption into the arachnoid villi and, more predominantly, through meningeal and olfactory lymphatics that ultimately drain into the peripheral lymphatics. Impaired CSF outflow has been postulated as a contributing mechanism in Alzheimer's disease (AD). Herein we conducted near-infrared fluorescence imaging of CSF outflow into the peripheral lymph nodes (LNs) and of peripheral lymphatic function in a transgenic mouse model of AD (5XFAD) and wild-type (WT) littermates. CSF outflow was assessed from change in fluorescence intensity in the submandibular LNs as a function of time following bolus, an intrathecal injection of indocyanine green (ICG). Peripheral lymphatic function was measured by assessing lymphangion contractile function in lymphatics draining into the popliteal LN following intradermal ICG injection in the dorsal aspect of the hind paw. The results show 1) significantly impaired CSF outflow into the submandibular LNs of 5XFAD mice and 2) reduced contractile frequency in the peripheral lymphatics as compared to WT mice. Impaired CSF clearance was also evidenced by reduction of fluorescence on ventral surfaces of extracted brains of 5XFAD mice at euthanasia. These results support the hypothesis that lymphatic congestion caused by reduced peripheral lymphatic function could limit CSF outflow and may contribute to the cause and/or progression of AD.

Foramen ovale cannulation guided by intraoperative computed tomography with magnetic resonance image fusion plays a role in improving the long-term outcome of percutaneous radiofrequency trigeminal rhizotomy

BackgroundPercutaneous radiofrequency trigeminal rhizotomy (RF-TR) is a well-established treatment for patients suffering from trigeminal neuralgia (TN) as a primary modality or for those refractory to medical treatment. However, few existing studies have identified intraoperative parameter or navigation technique that can be used to predict the rates of short-term or long-term pain relief. In this study, we analyzed patient characteristics, intraoperative parameters and technical factors, and postoperative changes in relation to immediate and long-term pain relief.MethodThis study included a total 252 patients in which 340 RF-TR were performed under the guidance of intraoperative computed tomography (iCT) alone or with magnetic resonance image (MRI) and iCT fusion imaging.ResultThe immediate pain relief of RF-TR with iCT alone and iCT with MR image guidance with or without cerebrospinal fluid (CSF) outflow were all above 90.4%. The 2-year pain relief rate of RF-TR using iCT alone and iCT with MR images guidance with or without CSF outflow were 47.8%, 39.8%, 71.7%, and 53.9% respectively. Significant factors for 2-year pain relief were CSF outflow, iCT with MR image fusion, non-recurrent TN, and presence of postoperative facial numbness.ConclusionThis preliminary study demonstrated foramen ovale cannulation under the aid of iCT with MR image guidance could improve 2-year pain relief.

Assessment of acid-base status and calcification risk after hemodialysis session

Arabia Terra is a region of Mars where signs of past-water occurrence are recorded in several landforms. Broad and local scale geomorphological, compositional and hydrological analyses point towards pervasive fluid circulation through time. In this work we focus on mound fields located in the interior of three casters larger than 40 km (Firsoff, Kotido and unnamed crater 20 km to the east) and showing strong morphological and textural resemblance to terrestrial mud volcanoes and spring-related features. We infer that these landforms likely testify the presence of a pressurized fluid reservoir at depth and past fluid upwelling. We have performed morphometric analyses to characterize the mound morphologies and consequently retrieve an accurate automated mapping of the mounds within the craters for spatial distribution and fractal clustering analysis. The outcome of the fractal clustering yields information about the possible extent of the percolating fracture network at depth below the craters. We have been able to constrain the depth of the pressurized fluid reservoir between ∼2.5 and 3.2 km of depth and hence, we propose that mounds and mounds alignments are most likely associated to the presence of fissure ridges and fluid outflow. Their process of formation is genetically linked to the formation of large intra-crater bulges previously interpreted as large scale spring deposits. The overburden removal caused by the impact crater formation is the inferred triggering mechanism for fluid pressurization and upwelling, that through time led to the formation of the intra-crater bulges and, after compaction and sealing, to the widespread mound fields in their surroundings.

SUCCESSFUL SURGICAL TREATMENT OF A NEWBORN WITH CHYLOPERITONEUM

The article describes clinical observation of treatment of a premature infant with chyloperitoneum. Accumulation of fluid in the abdominal cavity was diagnosed prenatally at 31–32 weeks of gestation. Premature surgical delivery was performed at 34– 35 weeks due to the high risk of antenatal fetal death. Paracentesis with fluid analysis was done; chylous exudate was confirmed. Total parenteral nutrition, octreotide and drainage of the abdominal cavity were used during conservative treatment. It was decided to perform a surgery as the therapy was ineffective. At the age of 2 months and 7 days laparotomy was conducted, abdominal organs were revised, lymph ducts were ligated, and abdominal cavity was drained producing a positive effect. The fluid outflow was terminated and the child was discharged in a satisfactory condition.

Ideas and perspectives: Development of nascent autotrophic carbon fixation systems in various redox conditions of the fluid degassing on early Earth

Abstract. The origin and development of the primary autotrophic metabolism on early Earth were influenced by the two main regimes of degassing of the Earth – reducing (predominance CH4) and oxidative (CO2). Among the existing theories of the autotrophic origin of life in hydrothermal environments, CO2 is usually considered to be the carbon source for nascent autotrophic metabolism. However, the ancestral carbon used in metabolism may have been derived from CH4 if the outflow of magma fluid to the surface of the Earth consisted mainly of methane. In such an environment, the primary autotrophic metabolic systems had to be methanotrophic. Due to the absence of molecular oxygen in the Archean conditions, this metabolism would have been anaerobic; i.e., oxidation of methane must be realized by inorganic high-potential electron acceptors. In light of the primacy and prevalence of CH4-dependent metabolism in hydrothermal systems of the ancient Earth, we propose a model of carbon fixation where the methane is fixed or transformed in a sequence of reactions in an autocatalytic methane–fumarate cycle. Nitrogen oxides are thermodynamically the most favorable among possible oxidants of methane; however, even the activity of oxygen created by mineral buffers of iron in hydrothermal conditions is sufficient for methanotrophic acetogenesis. The hydrothermal system model is considered in the form of a phase diagram, which demonstrates the area of redox and P and T conditions favorable for the development of the primary methanotrophic metabolism.

Thermo-osmosis and mechano-caloric couplings on THM responses of porous medium under point heat source

The influences of thermal gradient on the fluid flux (thermo-osmosis effect) and pore-pressure gradient on the heat flux (mechano-caloric effect) are usually ignored in the thermo-hydro-mechanical (THM) analysis of porous media. However, this assumption could have significant impacts on the analyses of geomaterials of relatively low permeability. In this paper, a point heat source was deeply buried in a saturated porous medium where the thermo-osmosis and mechano-caloric effects were considered. Laplace-Hankel transforms were applied to the linear equations governed by porothermoelasticity and to obtain the analytical solutions, the volumetric strain connected the displacements with the pore pressure and the temperature change. By applying the Laplace-Hankel inversion, the solutions in the real domain were obtained and verified by the existing results. The numerical results showed: (1) in geomaterials of low permeability, the mechano-caloric effect on the temperature change, heat flux and thermal gradient was negligible but the thermo-osmosis effect caused negative pore pressures which increased the effective stress of porous medium; (2) the thermo-osmosis effect pronouncedly drove the outflow of pore fluid away from the heat source which would be balanced by an inflow of pore fluid toward the heat source caused by the negative pore pressure.

Toward a new method for the design of combined sensible/latent thermal-energy storage using non-dimensional analysis

Placing an encapsulated phase-change material (PCM) on top of a packed bed of sensible filler material is an effective way of reducing the drop in the heat-transfer fluid (HTF) outflow temperature during discharging associated with a sensible thermal-energy storage (TES). So far, the literature lacks guidelines for the design of a combined sensible/latent TES. This study aims at developing a new method for the design of combined TES based on non-dimensional analysis. The method will provide a designer with non-dimensional plots, produced from quasi-steady-state results of simulations with a one-dimensional model, that relate performance parameters to geometrical, thermophysical, and operational parameters of the combined TES. In this paper, a simplified version of the method is demonstrated that allows the selection of a metallic PCM and its amount such that a specified drop in the HTF outflow temperature is attained during discharging, assuming a fixed sensible section of natural rocks and air as HTF. The plots show that the drop in the outflow temperature during discharging is minimized by selecting a PCM with a melting temperature equal to 98% of the HTF inflow temperature during charging. The plots also show that the heat of fusion, provided it exceeds a threshold, has a subordinate effect on the drop in the outflow temperature. Finally, the plots show that a smaller heat of fusion can be compensated with a larger height of the latent section. The method is illustrated with a specific example.

Computer Modeling Application of Fluid Outflow from Vessels

The aim of the paper is to evaluate numerical analysis of the fluid flow during the outflow from vessel orifices at various locations. The problems of the outflow velocities and pressure fields were well-chosen for the given purposes. The selected fluid flow problems were solved by numerical simulation using FEM in ANSYS. For numerical simulation, we used the basic steps to design an abstract model in the ANSYS virtual environment. Numerical simulation requires a geometric model complemented by physical properties of flowing fluids as well as both the initial and boundary conditions. It is then possible to calculate the velocity and pressure fields by numerical simulation for a particular fluid type. The results obtained from the numerical simulation were compared with those of the analytical solution. The results obtained from modeling and numerical simulation correspond to the actual values ​​with minimum deviations. The demonstrated type of the problem solved by numerical simulation and modeling confirmed the advantages and possibilities of flexible solutions for any combination of problems in the field of ​​fluid dynamics. Modeling and numerical simulation of fluid flow can provide results regarding the speed and the pressure fields in vessels and pipelines.

Steady Secondary Flow in a Plane Turbulent Free Jet

Asymptotic methods are applied to study a plane turbulent jet of a viscous incompressible fluid flowing out through a narrow slot into a space filled with a fluid. The complete Navier—Stokes equations are considered. The characteristic Reynolds number is assumed to be large, while the jet thickness is small. In analyzing the problem the method of many scales is used, which makes it possible to determine and investigate a steady secondary flow within the turbulent jet. The secondary steady solutions are analytically obtained for the normal and longitudinal velocity components and the pressure. It is shown that the self-induced fluid outflow of the jet core toward the jet periphery is the main secondary flow ensuring the supply of the kinetic energy from a maximum velocity zone into the turbulence production zone. The solutions obtained are in good agreement with the available experimental data.

Fluid Circulations at Structural Intersections through the Toro-Bunyoro Fault System (Albertine Rift, Uganda): A Multidisciplinary Study of a Composite Hydrogeological System

Regional fault structures along rift basins play a crucial role in focusing fluid circulation in the upper crust. The major Toro-Bunyoro fault system, bounding to the east of the Albertine Rift in western Uganda, hosts local fluid outflow zones within the faulted basement rocks, one of which is the Kibiro geothermal prospect. This major fault system represents a reliable example to investigate the hydrogeological properties of such regional faults, including the local structural setting of the fluid outflow zones. This study investigated five sites, where current (i.e., geothermal springs, hydrocarbon seeps) and fossil (i.e., carbonate veins) fluid circulation is recognized. This work used a multidisciplinary approach (structural interpretation of remote sensing images, field work, and geochemistry) to determine the role of the different macroscale structural features that may control each studied fluid outflow zones, as well as the nature and the source of the different fluids. The local macroscale structural setting of each of these sites systematically corresponds to the intersection between the main Toro-Bunyoro fault system and subsidiary oblique structures. Inputs from three types of fluid reservoirs are recognized within this fault-hosted hydrogeological system, with “external basin fluids” (i.e., meteoric waters), “internal basin fluids” (i.e., hydrocarbons and sediment formation waters), and deep-seated crustal fluids. This study therefore documents the complexity of a composite hydrogeological system hosted by a major rift-bounding fault system. Structural intersections act as local relative permeable areas, in which significant economic amounts of fluids preferentially converge and show surface manifestations. The rift-bounding Toro-Bunyoro fault system represents a discontinuous barrier for fluids where intersections with subsidiary oblique structures control preferential outflow zones and channel fluid transfers from the rift shoulder to the basin, and vice versa. Finally, this work contributes to the recognition of structural intersections as prime targets for exploration of fault-controlled geothermal systems.