Effect Of Compression Research Articles

Rheological properties and concentration evolution of thickened tailings under the coupling effect of compression and shear

Rheological properties and concentration evolution of thickened tailings under the coupling effect of compression and shear

Manipulation and diagnosis of femtosecond relativistic electron bunch using terahertz-driven resonators

Using strong electromagnetic fields generated by lasers to interact with electrons for precise diagnosis and manipulation of electron beams represents a recent focal point in accelerator technology. This approach surpasses the limitations of conventional RF technology, such as low electric field gradients and timing jitters, effectively enhancing the accuracy of ultrafast electron beam diagnostics and manipulations. As demands for precision continue to rise, the precise diagnosis of crucial parameters of ultrafast electron beams remains challenging. This study delves into the electromagnetic behavior of THz-driven devices and proposes an all-optical method utilizing single-cycle THz radiation to compress and characterize a 3 MeV electron beam. Particle tracking simulations demonstrate an astonishing compression effect, reducing the bunch length from 54.0 fs to 4.3 fs, and achieving sub-femtosecond bunch length measurement resolution. Moreover, when combined with an orthogonal THz streak camera, this method shows even greater potential in multi-bunch scenarios.

Electrosorption approach removing PFOA from wastewater using a MXene-polyaniline film

Perfluorooctanoic acid (PFOA) is a persistent organic pollutant found in various industrial effluents, posing significant environmental and health risks. Electrosorption of PFOA on MXene-polyaniline film from water was studied. The results of electrosorption kinetics showed that the functionalized MXene film with polyaniline resulting in an approximately 100 % increase in electrosorption capacitance for PFOA due to increasing of the MXene film's volumetric capacitance and modifying of surface chemistry of MXene. The maximum adsorption of PFOA on MXene and MXene-polyaniline films were 358.5 mg/g and 966.1 mg/g, respectively, at an initial concentration of 100 mg/L upon application of +1.0 V. Moreover, humic acid (HA) competing with the adsorption sites, sodium chloride through the double-layer compression effect, and pH affecting the amine or amide functional groups on MXene-polyaniline which inhibited PFOA adsorption onto MXene-polyaniline film were thoroughly examined. Lastly, the reversible adsorption–desorption cycles show that the MXene–polyaniline film possesses the potential to be used continuously. To address PFAS pollution in water sources, we think our approach can help build effective and long-lasting technology.

Numerical Simulation of Stress Disturbance Mechanism Caused by Hydraulic Fracturing of Shale Formation

Characterizing changes in rock properties is essential for the hydraulic fracture and re-fracture parameter optimization of shale formations. This paper proposed a hydraulic fracturing model to investigate the changes in rock properties during hydraulic fracturing using SPH, and the changes in the stress field and rock properties were quantitatively characterized. The simulation results indicated that the minimum horizontal principal stress increased by 10 MPa~15 MPa during fracture propagation, which is the main reason for the uneven propagation in multi-fracture propagation. Affected by the stress disturbance, the stimulated area was divided into four parts based on the changes in Young’s modulus and permeability; the more seriously the stress disturbance was affected, the higher the permeability of the stimulated zone was, and the smaller the stimulated zone was. Meanwhile, a zone with reduced permeability appeared due to the compression effect caused by the high injection pressure, and this increased with the increase in stress disturbance. The main reason for this was that strain formed because of the compression effect from the high injection pressure. The higher the stress disturbance, the higher the accumulated strain. This new model provides a new method for fracture parameter optimization, which also provides a foundation for the re-fracture parameter optimization of shale formations.

Impact of abdominal compression on heart and stomach motion for stereotactic arrhythmia radioablation.

To evaluate the effectiveness of abdominal compression (AC) as a respiratory motion management method for the heart and stomach during stereotactic arrhythmia radioablation (STAR). 4D computed tomography (4DCT) scans of patients imaged with AC or without AC (free-breathing: FB) were obtained from ventricular-tachycardia (VT) (n=3), lung cancer (n=18), and liver cancer (n=18) patients. Patients treated for VT were imaged both FB and with AC. Lung and liver patients were imaged once with FB or with AC, respectively. The heart, left ventricle (LV), LV components (LVCs), and stomach were contoured on each phase of the 4DCTs. Centre of mass (COM) translations in the left/right (LR), ant/post (AP), and sup/inf (SI) directions were measured for each structure. Minimum distances between LVCs and the stomach over the respiratory cycle were also measured on each 4DCT phase. Mann-Whitney U-tests were performed between AC and FB datasets with a significance of α=0.05. No statistical difference (all p values were>0.05) was found in COM translations between FB and AC patient datasets for all contoured cardiac structures. A reduction in COM translation with AC relative to FB was patient, direction, and structure specific for the three VT patients. A significant decrease in the AP range of motion of the stomach was observed under AC compared to FB. No statistical difference was found between minimum distances to the stomach and LVCs between FB and AC. AC was not a consistent motion management method for STAR, nor does not uniformly affect the separation distance between LVCs and the stomach. If AC is employed in future STAR protocols, the motion of the target volume and its relative distance to the stomach should be compared on two 4DCTs: one while the patient is FB and one under AC.

Case Report: Giant bronchogenic cyst compressing the pericardium and the lung hilum

Introduction: The bronchogenic cyst is a congenital anomaly of the trachea and the bronchi resulting in a malformation that develop in the bronchial tree, most often in the middle mediastinum. It is a benign pathology, often asymptomatic, however in the case of a large bronchogenic cyst, signs of compression of the intra-thoracic organs appear and early surgery is necessary to avoid complications. Case presentation: A 49-year-old patient was referred to our department with dry cough, dyspnea and chest tightness progressing for six months. Radiological exploration concluded that a giant bronchogenic cyst, 90 mm in diameter, was very probable. Surgery was performed via a right posterolateral thoracotomy. Intraoperatively, there was a large cystic formation 100mm*80 mm of the middle mediastinum in intimate contact with the origin of the right pulmonary artery, the lower right pulmonary vein as well as the right atrium exerting a compressive effect on the bronchi. The lesion was firmly adhered to the pericardium. The cystic was ‘en bloc’ resected in totality. The postoperative course was uncomplicated. Histological examination confirmed diagnosis of a bronchogenic cyst. The patient was asymptomatic throughout the follow-up period. Clinical discussion: Apart from the possibility of malignant degeneration, a bronchogenic cyst can increase in size and become huge causing serious complications. Despite the predictive diagnostic value of imaging, definitive diagnosis of a bronchogenic cyst is confirmed by surgical excision and pathological examination. Conclusions: Surgery is almost obligatory especially if the cyst is above a certain size (about 60 mm) and in the case of giant bronchogenic cysts.

Clinical Outcomes of Severe Rhinosinusitis Complicated with Cavernous Sinus Syndrome.

Background: Various diseases involving the cavernous sinus can cause a condition called cavernous sinus syndrome (CSS), which is characterized by ophthalmoplegia or sensory deficits over the face resulting from the compression effect of internal structure. While tumor compression is the most reported cause of CSS, statistical data on CSS caused by infections are limited. Its risk factors, treatment methods, and clinical outcomes are not well-documented. Methods: In this retrospective study, we reviewed the data of patients admitted to a tertiary medical center from 2015 to 2022 with a diagnosis of acute and chronic sinusitis and at least one diagnostic code for CSS symptoms. We manually reviewed whether patients were involved in two or more of the following cranial nerves (CN): CN III, CN IV, CN V, or CN VI, or at least one of these nerves with a neuroimaging-confirmed lesion in the cavernous sinus. Results: Nine patients were diagnosed with rhinosinusitis-related CSS. The most common comorbidity was type 2 diabetes, and the most common clinical manifestations were diplopia and blurred vision. The sphenoid sinus was the most affected sinus. One patient expired due to a severe brain abscess infection without surgery. The remaining patients underwent functional endoscopic sinus surgery, and 50% of the pathology reports indicated fungal infections. Staphylococcus spp. was the most cultured bacteria, and Amoxycillin/Clavulanate was the most used antibiotic. Only four patients had total recovery during the follow-up one year later. Conclusions: CSS is a rare but serious complication of rhinosinusitis. Patients with diabetes and the elderly may be at a higher risk for this complication. Even after treatment, some patients may still have neurological symptoms.

Clinical Efficacy of Percutaneous Balloon Compression Combined with Carbamazepine in the Treatment of Trigeminal Neuralgia: A Retrospective Study.

To investigate the effect of percutaneous balloon compression combined with carbamazepine on patients with Trigeminal Neuralgia (TN). The clinical data of 126 patients with TN admitted to our hospital from January, 2021 to January, 2022 were retrospectively analyzed. All patients underwent percutaneous balloon compression in our hospital. The patients were divided into a control group and an observation group, according to whether they continued to take carbamazepine after surgery. The general demographic data of patients, such as gender, age, family income, education level, pain site, diseased nerve, course of disease, and duration of pain were collected. Propensity score matching was used to balance the baseline data of the two groups, and the quality of life, treatment effect, and complications of the two groups were compared after matching. After treatment, the total effective rate of the observation group (95.00%) was higher than that of the control group (70.00%) (p < 0.05). Before treatment, there were no significant differences in the scores for quality of life dimensions between the two groups (p > 0.05). After treatment, the scores for each quality of life dimension in the observation group were higher than those in the control group. After treatment, the incidence of complications in the observation group (7.50%) was lower than that in the control group (30.00%) (p < 0.05). Percutaneous balloon compression combined with carbamazepine can effectively enhance the treatment of patients by improving their quality of life and reducing the occurrence of complications. These results can improve the clinical management of TN.

Synthesis of PtNi Nanoparticles to Accelerate the Oxygen Reduction Reaction.

We report the synthesis of core-shell Ni-Pt nanoparticles (NPs) with varying degrees of crystallographic facets and surface layers rich in Pt via a seed-mediated thermolytic approach. Mixtures of different surfactants used during synthesis resulted in preferential surface passivation, which in turn dictated the size, chemical composition, and geometric evolution of these PtNi NPs. Electrochemical investigations of these pristine core-shell Ni-Pt structures in the oxygen reduction reaction (ORR) show that their catalytic functionalities outperform the commercial Pt/C reference catalyst. The enhanced electrocatalytic ORR performances of these Pt-based PtNi NPs are correlated with the weakened oxygen binding strength or surface-adsorbed hydroxyl (OH) species on active Pt surface sites induced by the downshift of the d-band center as a result of compressive strain effects. Our studies offer a robust synthetic approach for the development of core-shell nanostructures for enhanced ORR catalysis.

The inviscid incompressible limit of Kelvin–Helmholtz instability for plasmas

Introduction: The Kelvin–Helmholtz Instability (KHI) is an interface instability that develops between two fluids or plasmas flowing with a common shear layer. KHI occurs in astrophysical jets, solar atmosphere, solar flows, cometary tails, planetary magnetospheres. Two applications of interest, encompassing both space and fusion applications, drive this study: KHI formation at the outer flanks of the Earth’s magnetosphere and KHI growth from non-uniform laser heating in magnetized direct-drive implosion experiments. Here, we study 2D KHI with or without a magnetic field parallel to the flow. We use both the GAMERA code, which solves the compressible Euler equations, and the STRATOSPEC code, which solves the Navier-Stokes equations under the Boussinesq approximation, coupled with the magnetic field dynamics. GAMERA is a global three-dimensional MHD code with high-order reconstruction in arbitrary nonorthogonal curvilinear coordinates, which is developed for a large range of astrophysical applications. STRATOSPEC is a three-dimensional pseudo-spectral code with an accuracy of infinite order (no numerical diffusion). Magnetized KHI is a canonical case for benchmarking hydrocode simulations with extended MHD options.Methods: An objective is to assess whether or not, and under which conditions, the incompressibility hypothesis allows to describe a dynamic compressible system. For comparing both codes, we reach the inviscid incompressible regime, by decreasing the Mach number in GAMERA, and viscosity and diffusion in STRATOSPEC. Here, we specifically investigate both single-mode and multi-mode initial perturbations, either with or without magnetic field parallel to the flow. The method relies on comparisons of the density fields, 1D profiles of physical quantities averaged along the flow direction, and scale-by-scale spectral densities. We also address the triggering, formation and damping of filamentary structures under varying Mach number or Atwood number, with or without a parallel magnetic field.Results: Comparisons show very satisfactory results between the two codes. The vortices dynamics is well reproduced, along with the breaking or damping of small-scale structures. We end with the extraction of growth rates of magnetized KHI from the compressible regime to the incompressible limit in the linear regime assessing the effects of compressibility under increasing magnetic field.Discussion: The observed differences between the two codes are explained either from diffusion or non-Boussinesq effects.

Effect of uniaxial compression on the microstructural evolution and magnetic properties of 20Mn23AlV non-magnetic structural steel

In this study, to evaluate the stability of the micro phase in the non-magnetic steel, the 20Mn23AlV high-manganese non-magnetic structural steel was compressed at room temperature. The research focused on analyzing the mechanical and magnetic properties of the compressed samples under conditions of substantial deformation. The results show that the Vickers hardness of the high-manganese non-magnetic structural steel exhibits a significant increase during deformation, primarily attributed to the formation of numerous deformation twins. X-ray diffraction (XRD) analysis confirms the exclusive presence of austenite phases, with no other phases detected. Additionally, when assessing the volume fractions of α′-martensite, calculations from hysteresis loops reveal values of approximately ∼0.03 % and ∼0.09 % for deformations at 56 % and 70 %, respectively. Remarkably, even with such minimal amounts of ferromagnetic α′-martensite generated, the steel still adheres to the criteria for non-magnetic steel usage. To further elucidate the formation of deformation twins and potential nucleation sites for α′-martensite, we conducted observations of microstructures under varying deformation conditions using transmission electron microscopy (TEM).

Coseismic and Early Postseismic Deformation Mechanism Following the 2021 Mw 7.4 Maduo Earthquake: Insights from Satellite Radar Interferometry and GPS

Exploring the deformation mechanism of the 2021 Mw 7.4 Maduo Earthquake is crucial for better understanding the seismic hazard of the faults with low strain rates inside the Bayan Har block. This study leverages deformation information derived from Sentient-1 A/B images and GPS data to investigate in detail the co- and postseismic deformation mechanisms using multiple methods. The main results are as follows. First, the postseismic InSAR time series robustly identified the reactivation of the Changmahe fault, indicating the impact of the Maduo event on surrounding active faults. Second, the joint inversion of Interferometric Synthetic Aperture Radar and GPS revealed that (1) there was a complementary and partially overlapping relationship between the coseismic slip and postseismic afterslip of the main rupture; and (2) the Changmahe fault exhibited thrust compression dislocation in the early stage and experienced a sustained compressive effect from afterslip in the one year after the mainshock. Third, modeling the processes of viscoelastic relaxation and poroelastic rebound revealed that the postseismic deformation was probably caused by a combination of afterslip (near-field) and viscoelastic relaxation (near and far field). Fourth, the stress changes driven by the Maduo event revealed that the seismic gaps inside the Maqin-Maqu segment and the Kunlun Pass-Jiangcuo fault will be potential seismic risks in the future.

Effectiveness of vertical compression of locking plate combined with hollow screws in treatment of Sanders type Ⅱ and Ⅲ calcaneal fractures

To probe into the effectiveness of vertical compression of locking plate combined with hollow screws in the treatment of Sanders type Ⅱ and Ⅲ calcaneal fractures. The clinical data of 128 patients with Sanders type Ⅱ and Ⅲ calcaneal fractures who were admitted between March 2019 and April 2022 and met the selection criteria were retrospectively analyzed. Among them, 65 patients were treated with locking plate combined with hollow screw vertical compression (study group), and 63 patients were treated with simple locking plate (control group). There was no significant difference in baseline data between the two groups ( P>0.05), such as gender, age, fracture side and Sanders classification, cause of injury, time from injury to operation. The operation time, intraoperative blood loss, hospital stay, and fracture healing time were recorded and compared between the two groups. Before operation and at 12 months after operation, the American Orthopaedic Foot and Ankle Association (AOFAS) score (including total score, pain score, functional score, and alignment score) was used to evaluate the recovery of foot function, and imaging indicators such as calcaneal width, calcaneal height, calcaneal length, Böhler angle, and Gissane angle were measured on X-ray films. All patients were followed up 12 months after operation. There was no significant difference in operation time, intraoperative blood loss, hospital stay, and fracture healing time between the two groups ( P>0.05). Poor wound healing occurred in 1 case in the study group and 2 cases in the control group. At 12 months after operation, there was no significant difference between the two groups in the pre- and post-operative difference of calcaneal length, calcaneal height, Gissane angle, and Böhler angle ( P>0.05). However, the pre- and post-operative difference in calcaneal width in the study group was significantly higher than that in the control group ( P<0.05). The pre- and post-operative difference of AOFAS total score in the study group was significantly higher than that in the control group ( P<0.05), and further analysis showed that the pre- and post-operative difference of pain and function scores in the study group were significantly higher than those in the control group ( P<0.05), while there was no significant difference in the pre- and post-operative difference of force score between the two groups ( P>0.05). Compared with simple locking plate treatment, the treatment of Sanders type Ⅱ and Ⅲ calcaneal fractures with vertical compression of locking plate combined with hollow screws can more effectively improve the width of the subtalar calcaneal articular surface, avoid peroneal longus and brevis impingement, reduce pain, and increase the range of motion of the subtalar joint, and the effectiveness is better.

Modular organization of functional brain networks in patients with degenerative cervical myelopathy

Previous studies have indicated that brain functional plasticity and reorganization in patients with degenerative cervical myelopathy (DCM). However, the effects of cervical cord compression on the functional integration and separation between and/or within modules remain unclear. This study aimed to address these questions using graph theory. Functional MRI was conducted on 46 DCM patients and 35 healthy controls (HCs). The intra- and inter-modular connectivity properties of the whole-brain functional network and nodal topological properties were then calculated using theoretical graph analysis. The difference in categorical variables between groups was compared using a chi-squared test, while that between continuous variables was evaluated using a two-sample t-test. Correlation analysis was conducted between modular connectivity properties and clinical parameters. Modules interaction analyses showed that the DCM group had significantly greater inter-module connections than the HCs group (DMN-FPN: t = 2.38, p = 0.02); inversely, the DCM group had significantly lower intra-module connections than the HCs group (SMN: t = − 2.13, p = 0.036). Compared to HCs, DCM patients exhibited higher nodal topological properties in the default-mode network and frontal–parietal network. In contrast, DCM patients exhibited lower nodal topological properties in the sensorimotor network. The Japanese Orthopedic Association (JOA) score was positively correlated with inter-module connections (r = 0.330, FDR p = 0.029) but not correlated with intra-module connections. This study reported alterations in modular connections and nodal centralities in DCM patients. Decreased nodal topological properties and intra-modular connection in the sensory-motor regions may indicate sensory-motor dysfunction. Additionally, increased nodal topological properties and inter-modular connection in the default mode network and frontal-parietal network may serve as a compensatory mechanism for sensory-motor dysfunction in DCM patients. This could provide an implicative neural basis to better understand alterations in brain networks and the patterns of changes in brain plasticity in DCM patients.

Effect of Compression Dressing After Upper Eyelid Blepharoplasty on Edema, Ecchymosis, Pain, and Ocular Surface Irritation.

To investigate the effect of a compression dressing (CD) on edema, ecchymosis, aesthetic outcome, pain, and ocular surface irritation after upper eyelid blepharoplasty. We conducted a case-control study. Bilateral blepharoplasty was performed on both upper eyelids at the same time in patients with dermatochalasis. One side was randomized for CD. Edema and ecchymosis were scored at a 4-point rating scale by a blinded observer 1 day (D1), 1 week (D7), and 8 weeks (D56) after surgery; the same for scar formation regarding redness and bulging at D7 and D56. Aesthetic outcome was evaluated by the patient and blinded observer using the global aesthetic improvement score at D1, D7, and D56. Postoperative pain was scored by the patients using a visual analogue scale (0 to 10) at D1. At D1 patients had to state which side they felt more comfortable. Edema, scar formation and aesthetic outcome evaluated by the patient and blinded observer did not differ between the 2 sides on any of the survey days ( p > 0.05). The median degree of ecchymosis was slightly higher on the lids without CD at D1 (1 [0-2] vs. 1.5 [0-2]; p = 0.495) and D7 (0 [0-2] vs. 0.5 [0-2]; p = 0.183), but not statistically significant. Postoperative pain was similar regardless to the use of CD ( p = 0.925). The majority (55%) found the side without CD more comfortable. There was no case of corneal erosion and corneal staining was similar in both groups ( p > 0.05). Using a CD after blepharoplasty shows no advantages regarding postoperative edema, ecchymosis, scar formation, or aesthetic results in the early postoperative period. As most patients preferred the noncovered side, CD can be omitted after blepharoplasty without inferiority for the postoperative results. NCT06111170.

A compressible degree of freedom as a means for improving the performance of heaving wave energy converters

A compressible degree of freedom (CDOF) can provide a means of improving wave power capture by adjusting the system stiffness and providing short-term energy storage, reducing or even eliminating the requirement for two-way electrical power flow as is typical in wave energy control systems. With the overarching goal of investigating and facilitating the application of a CDOF within wave energy converter (WEC) design, this paper focuses primarily on the case of heaving buoys, and on using air volumes to provide the compressible spring effect. Analytical formulae for the natural frequencies are used to gain fundamental insights into the main design considerations. Numerical methods are used to augment this understanding, helping to elucidate the effect of geometric parameters and scale on the required compressible volumes and the efficacy of the CDOF. Beginning with the WaveBot WEC, case studies are then used to demonstrate the design drivers in a more applied context, as well as highlighting the benefit of a self-reacting power take-off (PTO) system. The assimilation of these results with the findings of a detailed literature review culminates in a set of recommendations (or guiding principles) for designing a compressible degree of freedom to improve the performance of a heaving wave energy converter. These recommendations apply both to full-scale WECs, and to the design of scale physical modelling studies for validating the analytical and numerical models.

Internally heated and fully compressible convection: Flow morphology and scaling laws

In stars and planets natural processes heat convective flows in the bulk of a convective region rather than at hard boundaries. By characterizing how convective dynamics are determined by the strength of an internal heating source we can gain insight into the processes driving astrophysical convection. Internally heated convection has been studied extensively in incompressible fluids, but the effects of stratification and compressibility have not been examined in detail. In this work, we study fully compressible convection driven by a spatially uniform heating source in two-dimensional (2D) and 3D Cartesian, hydrodynamic simulations. We use a fixed temperature upper boundary condition which results in a system that is internally heated in the bulk and cooled at the top. We find that the flow speed, as measured by the Mach number, and turbulence, as measured by the Reynolds number, can be independently controlled by separately varying the characteristic temperature gradient from internal heating and the diffusivities. Two-dimensional simulations at a fixed Mach number (flow speed) demonstrate consistent power at low wave number as diffusivities are decreased. We observe convection where the velocity distribution is skewed towards cold, fast downflows and that the flow speed is related to the length scale and entropy gradient of the upper boundary where the downflows are driven. We additionally find a heat transport scaling law which is consistent with prior incompressible work. Published by the American Physical Society 2024

Nanoscopic Interfacial Hydrogel Viscoelasticity Revealed from Comparison of Macroscopic and Microscopic Rheology.

Deviations between macrorheological and particle-based microrheological measurements are often considered to be a nuisance and neglected. We study aqueous poly(ethylene oxide) (PEO) hydrogels for varying PEO concentrations and chain lengths that contain microscopic tracer particles and show that these deviations reveal the nanoscopic viscoelastic properties of the particle-hydrogel interface. Based on the transient Stokes equation, we first demonstrate that the deviations are not due to finite particle radius, compressibility, or surface-slip effects. Small-angle neutron scattering rules out hydrogel heterogeneities. Instead, we show that a generalized Stokes-Einstein relation, accounting for an interfacial shell around tracers with viscoelastic properties that deviate from bulk, consistently explains our macrorheological and microrheological measurements. The extracted shell diameter is comparable to the PEO end-to-end distance, indicating the importance of dangling chain ends. Our methodology reveals the nanoscopic interfacial rheology of hydrogels and is applicable to different kinds of viscoelastic fluids and particles.

Sub-filter-scale shear stress analysis in hypersonic turbulent Couette flow

Direct numerical simulations of hypersonic turbulent Couette flows are performed for top-wall Mach numbers of 6, 7 and 8, inspired by non-reactive high-enthalpy wind tunnel free-stream conditions, with the goal of analysing the physical processes driving the sub-filter-scale (SFS) stresses to inform development of large-eddy simulation techniques for hypersonic wall-bounded flows. Semi-local scaling laws collapse mean profiles and second-order turbulent statistics well, in spite of the strong wall-normal gradients of temperature and density. On the other hand, the SFS shear stresses exhibit an unexpected profile characterized by a region of pronounced shear stress deficit, which becomes more pronounced for higher Mach numbers. Instantaneous visualizations suggest that the SFS shear stress deficit is induced by the counter-gradient resolved momentum transport driven by residual velocity motions at the interface between high-density low-speed streaks being ejected away from the wall, and low-density high-speed ones replacing the displaced fluid, qualifying this as a compressibility effect. It is shown that the SFS shear stresses are primarily driven by second-order interactions between residual velocities, in spite of their triply nonlinear nature. This, in turn, motivated a statistical quadrant analysis revealing the presence of a SFS shear stress deficit, that is, SFS processes driving momentum transport of the resolved field towards the top wall. Additionally, higher-Reynolds-number simulations reveal that there is an upper limit of spatial filter widths to resolve large-scale structures, and such deficit is observable at any Reynolds number when a reasonable spatial filter is applied.

Rehabilitation of cancer patients: the use of pneumatic compression in secondary lymphedema treatment

Complex decongestive therapy is a cornerstone of conservative chronic lymphedema treatment. There are other conservative treatment options that include intermittent pneumatic compression. Its mechanism of action is based on pressure applying on the underlying tissues and promoting the lymph flow through the lymphatic structures. Pneumatic compression was invented in 1972; nevertheless it has not found widespread support of professional community as a self-sufficient method of conservative lymphedema treatment, though it’s used a lot in many rehab clinics worldwide.Aim. To determine the indications and effectiveness of pneumatic compression, as well as to identify the possibility of using this method in the practice of treating lymphatic edema.