Ratio Of Maximum Velocity Research Articles

City configurations to optimise pedestrian level ventilation and wind comfort

Mediterranean coastal cities encounter two conflicting urban environmental challenges. First, strong winds that pose a risk of pedestrian wind discomfort on coastal streets, and second, weak winds that lead to inadequate outdoor ventilation in inner urban fragments. This study aims to optimise pedestrian level ventilation and wind comfort in Izmir, a compact coastal city in the Mediterranean climate. Three hypothetical city configurations were created based on four morphological parameters: street layout, urban street canyon form, tower layout, and tower height variation. Computational fluid dynamics simulations of the city configurations were performed and validated by wind tunnel experiments. The weak, comfortable, and strong winds were determined and mapped at the pedestrian level to assess each city configuration's performance. The results show that using the strategy of a shifted coastal street layout with adding towers on second-row blocks results in a 20 % reduction of the maximum wind velocity ratio on coastal streets compared to a grid street layout without towers. Moreover, positioning step-up towers on step-up city blocks and shifted towers on step-down city blocks can increase pedestrian-level ventilation efficiency by up to 73 %. The research methodology and findings can be transferred to other climates and urban environments and guide urban designers.

Difference in the immediate effect on positional nystagmus for head positions with interval time during Epley maneuver: a randomized trial.

The Epley maneuver (EM) shows immediate effect, wherein disappearance of positional nystagmus occurs soon after the EM. Our previous study showed that setting interval times during the EM reduced the immediate effect. The purpose of this study is to identify the head position for which interval time reduces the immediate effect. Fifty-one patients with posterior canal type of benign paroxysmal positional vertigo (BPPV) were randomly assigned to the following three groups: 10min interval time set at the first head position of the EM in group A, at the third head position in group B, and at the fourth head position in group C. The primary outcome measure (POＭ) was the ratio of maximum slow-phase eye velocity of positional nystagmus soon after the EM, compared with that measured before the EM. A large ratio value indicates a poor immediate effect of the EM. The POＭ in group A (0.07) was smallest (B: 0.36, C: 0.49) (p < 0.001). The interval times at the third and fourth head positions reduced the immediate effect of the EM. Our previous study showed that the effect of BPPV fatigue is continued by maintaining the first head position of the EM. BPPV fatigue constitutes fatigability of positional nystagmus with repeated performance of the Dix-Hallpike test. Our findings may be interpreted in accordance with the theory that the immediate effect of the EM is BPPV fatigue itself, because we observed that the effect of BPPV fatigue is strongest in group A.

Ultrasonographic diagnosis of fetal hemodynamic parameters in pregnant women with diabetes mellitus in the third trimester of pregnancy

ObjectiveIt was to investigate the diagnosis of fetal hemodynamics in pregnant women with diabetes mellitus in the third trimester of pregnancy by color Doppler ultrasonography. Methods55 women with gestational diabetes mellitus (GDM) in the third trimester of pregnancy who were clinically diagnosed and treated in Haian City People's Hospital of Jiangsu Province were selected as the observation group, and 55 pregnant women with normal prenatal examination results were selected as the controls. The hemodynamic parameters of fetal middle cerebral artery (MCA), umbilical artery (UA), and renal artery (RA) were detected, including the ratio of maximum systolic blood flow velocity to end-diastolic blood flow velocity (S/D), resistance index (RI) and arterial pulsation index (PI). Fasting serum levels of maternal patients were collected for detecting Cystain C (Cys C) and homocysteine (Hcy) to analyze the predictive value of serological indexes and target arterial hemodynamics parameters for adverse pregnancy outcome (APO). ResultsThe results showed that compared with controls, in the observation group, RI, PI, and S/D of MCA and RA increased significantly, while RI, PI and S/D of UA decreased obviously (P < 0.05), the levels of serum Cys C and Hcy were clearly increased (P < 0.05). The APO rate of controls and observation group was 10.91 % and 25.45 %, respectively. It was found that the area under the curve of serum Cys C, Hcy, and the APO predicted by the hemodynamic parameters of fetal MCA, UA, and RA were all greater than 0.75 (P < 0.05). Multiple Logistic regression analysis showed that serum Cys C and Hcy, and the hemodynamic parameters of fetal MCA, UA and RA were correlated with APO (P < 0.05). ConclusionIn summary, maternal blood glucose level can affect fetal hemodynamic parameters. In the third trimester of pregnancy, the changes of blood flow parameters of fetal MCA, UA, RA, and maternal serum Cys C and Hcy levels are helpful to understand fetal status in utero, and can be used to predict APO.

Numerical and experimental investigation of geometric parameters influence on power generation of INVELOX wind turbine

Wind energy is a key contributor to current transitional trends toward green energy resources. Wind turbines, therefore, act as the main of the wind energy power generation hierarchy, which converts the kinetic energy of wind into electric power. However, low wind velocity is a limiting factor that significantly diminishes the power generation capacity of wind turbines. Alternatively, ducted wind turbines provide a sustainable solution for application in areas with low wind velocity. In the present work, a numerical investigation has been performed to investigate the variation in the power generation capacity of INVELOX with varying geometric parameters. Initially, a numerical investigation of the original INVELOX model was performed to validate the numerical framework and establish the obtained results as a reference. Afterwards, the shape of the funnel, fins/supporting structure, and venturi parameters were varied to analyze their influence on the maximum velocity achieved at the throat. Subsequently, a novel semi-dome concept is added to the model based on numerical results. The results showed that the maximum velocity ratio has been improved from 2.125 to 3.13. Furthermore, power generation capacity was also increased by 3.2 times compared with the original INVELOX design by applying optimized geometric parameters and the semi-dome concept.

ST-segment elevation myocardial infarction and the clinical significance of differentiated electrocardiogram

Aim. To evaluate the markers of changing dynamics recorded by digital processing of routine ECG using own diagnostic complex software “Smart-ECG” in patients with ST-segment elevation myocardial infarction (STEMI) based on the results of a 40-day follow-up. Materials and methods. The main group consisted of 20 patients with STEMI according to the ESC guidelines (2017) (mean age of males 56.11 ± 11.62, n = 10; mean age of females 58.22 ± 13.11, n = 10). ECG were analyzed using own developed diagnostic complex software “Smart-ECG” on the 1st, 10th, 40th day after STEMI. The first derivative of T wave – ratio of maximum velocity (MVR), inclination angle (β) and inclination height (H) of ST segment was calculated. The control group – 20 apparently healthy people. Results. MVR indicators decreased by 61.90 %, 68.20 % and 51.48 % on the 1st, 10th and 40th day, respectively, after STEMI as compared to those of the control group (p &lt; 0.01). At the moment of the maximum ST segment elevation, the height (H) of ST inclination was 347.7 % increased (p &lt; 0.01); on the 40th day, H was 25 % increased, close to control indicators, with ST segment shift to isoline (р &gt; 0.05). During the acutest period, the angle β increased by 172.2 % (p &lt; 0.01) and then decreased by 15.8 % at the recovery phase, but insignificantly. Conclusions. Self-developed medical software “Smart-ECG” for qualitative evaluation of ECG is an effective tool to diagnose pathological changes in the myocardium, makes it possible to improve the specificity, sensitivity and prognostic significance of ECG in STEMI. The significant decrease in MVR has been detected at all stages of STEMI, which was associated with a violation of electrogenesis in the repolarization phase; the critical increase in ST slope indicators (angle β and height H) on the 1st day has been found as a characteristic of ST elevation, as well as its decrease on the 40th day as a sign of reduced potential difference between healthy and damaged areas of the myocardium during the recovery stage.

Study of an Optimized Mechanical Oscillator for the Forced Vibration of the Soil Cutting Blade

In the nursery sector, the transport and planting of trees must occur with the roots wrapped in a ball of the original earth. The cutting of the original soil can be carried out with a semicircular vibrating blade moved by an oscillator mounted on a self-propelled machine. The oscillator produces an excitation torque supplied to the blade together with the soil cutting torque. The advantage of the vibrating blade is a reduction in the cutting torque of up to 70%. However, to correctly design the oscillator, we need to investigate the link between the maximum displacement of the blade, the maximum oscillation velocity, the cutting velocity, the dry friction, the excitation torque, the elastic torque, the cutting torque, the required power, the required energy, and the excitation frequency. The maximum displacement and velocity ratio need to have the right values to minimize the cutting torque and to avoid the springs reaching the end of stroke; otherwise, vibrations are transmitted to the machine and to the operator. Therefore, starting from the forced oscillation differential equation and using an approximate solution method developed by Den Hartog, along with some experimental data, a mathematical model was constructed to optimize the oscillator design. After construction, it was coupled to blades of various diameters (0.6, 0.9, and 1.2 m) to undergo experimental tests. The soil cutting tests highlighted the achievement of the above objectives and, at the same time, confirmed the validity of the Den Hartog equations used to calculate the phase lag and the maximum displacement, resulting in an average error of 4.4% and a maximum error of 6.4%.

Influence of Slip and Orientation on Entropy Generation Due to Natural Convection in a Square Cavity

Abstract Numerical simulations are performed to deduce the effects of slip wall and orientation on entropy generation due to natural convection (NC) in a square cavity for Rayleigh number (Ra) = 105. The laterally insulated square cavity, heated at the bottom wall and cooled at the top wall, is subjected to various orientation angles (ϕ) and slip velocities characterized by the Knudsen number (Kn). The two components of entropy generation, i.e., entropy generation due to heat transfer (SΘ) and entropy generation due to fluid friction (SΨ), are separately investigated by varying the orientation from 0 deg to 120 deg in steps of 15 deg and Knudsen number from 0 (no-slip) to 1.5 in steps of 0.5. Evidence indicates that, for most cases considered, entropy generation due to fluid friction (SΨ) dominates the one due to heat transfer (SΘ). It is observed that the slip velocity on the isothermal walls (us,iso) has a strong influence on SΘ whereas the variations in SΨ are closely connected to the change in the rate of shear strain. Interestingly, the presence of corner vortices and the secondary circulations near the core of the cavity are also found to affect the variation in entropy generation. The existence of active zones of SΘ in the vicinity of isothermal walls and their elongation and migration while changing the orientation is another unique characteristic noticed in this study. A new parameter called maximum velocity ratio (MVR) is also proposed to highlight the variation in velocity components within the enclosure.

Linear site responses from U.S. borehole arrays: Primary site-response parameters and proxies

Site response, site resonance in particular, is a great concern in earthquake engineering. However, scientists and engineers have yet to reach a consensus on the most important parameters or proxies to characterize or quantify site response. In this investigation, we identified the most important parameters at 12 borehole arrays in the United States by analyzing weak-motion empirical and theoretical site responses in terms of soil-to-rock spectral ratios and ratios of response spectra at each site in the frequency range of engineering interest, 0.1–10 Hz (i.e., a period range of 0.1–10 s). From these ratios, we extracted two sets of parameter pairs: the fundamental and peak mode frequencies, f0 and fp, respectively, and their corresponding amplifications, A0 and Ap, respectively. We also characterized the Vs profiles using the shear-wave velocity ratio (Rj) and impedance ratio IRj and determined the maximum velocity and impedance ratios (Rmax and IRmax) for these borehole arrays. Both the linear empirical and theoretical results confirm that site response is site-specific and controlled predominantly by each site's in situ shear-wave velocity (Vs) profile in terms of shear-wave velocity ratios or impedance ratios, the maximum velocity or impedance ratio in particular. Our studies suggest that a minimum bedrock-sediment shear-wave velocity ratio of about 2.5 (i.e., Rmax≥2.5) or impedance ratios of about 3.0 (i.e., IRmax ≥ 3.0) is required to generate site resonance. Our results show that the fundamental mode is the most important mode for quantifying site response for engineering purposes at sites where amplifications are controlled by site resonance because it is the dominant mode on the ratios of response spectra. We also compared five proxies derived from each site's velocity profile—the time-averaged shear-wave velocity for the top 30 m (VS30), depth to bedrock or basin depth (Zb), time-averaged shear-wave velocity of sediment (Vs‾), ratio of bedrock shear-wave velocity (Vsb) to Vs‾ (Rmax), and ratio of bedrock impedance to the average sediment impedance (IRmax)—with the empirical fundamental resonant mode parameters. The comparisons revealed that Zb and Rmax (or IRmax) are the best pair of proxies to parameterize the fundamental resonant mode parameters. The comparisons also show that VS30 is not the best proxy and that no single proxy is sufficient to parameterize the fundamental resonant mode parameters.

Left renal vein entrapment in postural proteinuria: the diagnostic utility of the aortomesenteric angle.

Nutcracker syndrome related to the left kidney vein compression is a cause of orthostatic proteinuria during childhood. Some studies have shown that the ratios between maximum velocities and anterior-posterior diameters of hilar and aortomesenteric segments of the left kidney vein between upright and supine positions must be more than 4 in order to make a Nutcracker syndrome diagnosis. Our aim was to investigate whether the use of a decrease in aortomesenteric angle between upright and supine positions in the presence of isolated orthostatic proteinuria can be a criterion for the diagnosis of Nutcracker syndrome. Relevant patient information, which included demographic data, clinical examination findings, laboratory data, urinary system ultrasound, and kidney color flow Doppler ultrasound results, were prospectively collected. Thirty-nine pediatric patients with orthostatic proteinuria were included in the study. Left kidney vein compression findings were demonstrated in 31 patients. The ratio of maximum velocities of hilar and aortomesenteric segments of the left kidney vein between upright and supine positions was above 4 in only 7 of our patients. Ratio of aortomesenteric angle between upright and supine positions was significantly decreased for patients with left kidney vein compression findings. Conclusion: The use of a decrease in the ratio of aortomesenteric angle between upright and supine positions in the presence of orthostatic proteinuria, instead of the ratios for maximum velocities and anterior-posterior diameters of hilar and aortomesenteric segments, can be more helpful for the diagnosis of Nutcracker syndrome in the differential diagnosis of orthostatic proteinuria. What is Known: •Proteinuria may be a sign of an impending kidney disease •Nutcracker syndrome is a cause of orthostatic proteinuria. What is New: •Ratio of aortomesenteric angle between upright and supine positions > 0.6 can be used for Nutcracker syndrome diagnosis.

Numerical simulation on acoustic streaming characteristics in boiler tube array

Strong sound can produce acoustic streaming around the tube, which can change the flow state around the tube, and then affect the heat exchange between the tube and the surrounding medium. In order to obtain the influence law of sound wave on the heat transfer characteristics in the tube array, firstly, we study the acoustic streaming and heat transfer characteristics around a single cylindrical tube by the scheme of theoretical derivation and simulation. On this basis, we study the acoustic streaming and heat transfer characteristics in the periodic tube array. The results show that the acoustic streaming structure outside the tube is axially symmetric, and the flow direction of the inner vortices and the outer vortices are opposite. When the frequency is constant, sound pressure level (SPL) only changes the acoustic streaming velocity, not the acoustic streaming distribution. As the frequency continues to increase, the velocity peak gradually shifts from the inner vortex to the outer vortex, so the outer vortex velocity gradually becomes the main body of flow. Low frequency and high intensity sound waves can form strong acoustic streaming movement and enhance heat transfer outside the tube. In the tube array, the acoustic streaming distribution should consider the effect of different incident directions on crystal plane spacing. For incident angle φ = 0°∼34°, the ratio of maximum velocity of outer vortex to the one of inner vortex an Nusselt number (Nu) are increasing with φ increasing. In this stage, the heat transfer effect changes greatly with the change of angle. For incident angle φ = 35°∼45°, the inner and outer vortex flow velocity and Nu increases together, but the scale of outer vortex decreases. In this stage, with the change of angle, the heat transfer effect changes less due to the reduction of the scale of outer vortex dominating heat transfer between tubes. In tube arrays, the optimal flow field incidence angle is φ = 34 °and the optimal heat transfer incidence angle is φ = 45°. The sound band gap and sound pressure level enhancement exist in the tube array, which affects the acoustic streaming distribution. The results are helpful to reveal the mechanism of acoustic streaming more clearly and provide a basis for the augmentation of heat transfer in tube arrays by acoustic waves.

Method for Identifying and Forecasting Mining-Induced Earthquakes Based on Spatiotemporal Characteristics of Microseismic Activities in Fankou Lead/Zinc Mine

The risks associated with underground mining at Fankou Lead/Zinc Mine in South China are growing due to the large-scale mining activities there. To recognize mining-induced earthquakes and assess the risk per mining level, a microseismic monitoring system, which is used to record microseismic events, is installed at multiple mining levels in Fankou Lead/Zinc Mine. The purpose of this study is to identify mining-induced earthquakes and to evaluate the risk per mining level by analyzing the spatiotemporal characteristics of microseismic activities in the Fankou Lead/Zinc Mine. In this study, the Gutenberg-Richter (G-R) relationship is applied to compute the b-value, which is used to obtain the maximum magnitude (M (max)) of microseismic event that probably occurs at each mining level. Then, the evaluation of the recurrence period for M (max) and the probability of the microseismic event with the magnitude M (max) is carried out and the M (max) at each mining level is determined based on the recording period of microseismic events. The results show that factors such as the maximum rock vibration velocity, source parameters, displacement, microseismic waveform and energy ratio (ES/EP) can be used to distinguish whether a recorded microseismic event is mining-induced earthquake. Additionally, we propose a method to assess the possibility of mining-induced earthquake at each mining level based on M (max) and predict the recurrence time of microseismic event with the magnitude M (max). The of two years results of microseismic events monitoring demonstrate that the current study is promising for identifying mining-induced earthquakes, assessing the risk of mining-induced earthquakes, predicting the potential maximum microseismic event in a region and estimating its recurrence period and its probability in the Fankou Lead/Zinc Mine.

Program «Smart ECG – ranolazin» - own experience and world approach

Purpose - comprehensive analysis of the world approach of the use of ranolazine in various clinical trials and the introduction of the program "Smart ECG" to assess the effectiveness of ranolazine.Matherial and methods. Evaluation of European guidelines, analysis of global randomized clinical trials of the ranolazine use, presentation of our own trial: we examined 40 patients with Q wave myocardial infarction (STEMI), were instituted basic therapy according to the modern recommendations which contained interventional treatment with restoration of patency of a heart attack-conditioned coronary artery, double antiplatelet therapy, statins, β-adrenergic blocker, angiotensin-converting enzyme inhibitors, aldosterone antagonists with addition of ranolazine (group I, 30 patients diagnosed STEMI), control - group II, 10 patients with STEMI, who received basic therapy without addition of ranolazine. Results. Analysis of clinical trials (CARISA, MARISA, ERICA, TERISA, MERLIN-TIMI, RIVER-PCI, RIMINI-TRIAL) proved the effectiveness of ranolazine as an antianginal and anti-ischemic drugs. The use of own program «Smart ECG» demonstrates the positive effect of ranolazine on STEMI and requires further implementation.Conclusion. In the European Society of Cardiology guidelines of the management of stable angina pectoris, ranolazine is given a class IIa (level of evidence B) recommendation as a second-line treatment to reduce angina frequency and improve exercise tolerance in subjects who cannot tolerate, have contraindications to, or whose symptoms are not adequately controlled by β- adrenergic blockers, calcium channel blockers and long-acting nitrates. In subjects with baseline low heart rate and low blood pressure, ranolazine may be considered as a first-line drug to reduce angina frequency and improve exercise tolerance - class IIa (level of evidence C) recommendation. Own study, which partially reflects the global approach according to the analyzed clinical studies, demonstrates the positive effect of ranolazine for patients with STEMI - analogue scale EQ–VAS indicates a positive effect, positive influence on the markers of electrical myocardial instability: decreasing of the probability of cases of SDNN decrease, depression of QT and maybe increase of ratio of maximum velocity for differentiated T wave.

Two-phase flow regime identification based on the liquid-phase velocity information and machine learning

Two-phase flow regime identification in a horizontal pipe was realized based on the liquid phase velocity information and the machine learning method. Ultrasound Doppler velocimetry was employed to measure the liquid velocity. Statistical features extracted from the velocity time series data, such as mean, root mean square, and power spectral density, were used to realize real-time flow regime identification. In addition, two novel parameters—maximum velocity ratio and maximum velocity difference ratio—were proposed to identify plug and decaying slug flow. Different classification algorithms were employed to achieve a high identification accuracy. Moreover, transient flow regime identification with a fast response was realized based on two classification algorithms—long–short term memory and convolutional neural network. The results show that the accuracy of real-time flow regime identification based on a flow regime map can reach up to 93.1% using support vector machine, the maximum velocity ratio and maximum velocity difference ratio are effective in identifying plug and decaying slug flow, and transient flow regime identification under slug flow condition can be realized with an accuracy of 94% based on a convolutional neural network (CNN). Decaying slugs with long lengths confuse the CNN and are responsible for the error in identification. The results presented herein are expected to expand the available knowledge on two-phase flow regime identification.

IMPLEMENTATION OF INFORMATION SYSTEMS IN DIAGNOSTICS-ECG DIGITALIZATION AND «SMART-ECG» IMPLEMENTATION WITH АNALYSIS OF RANOLASINE EFFICIENCY, OPTIMIZATION OF TREATMENT OF ST SEGMENT ELEVATION SYNDROME

This paper presents the possibility and expediency of using information systems in diagnostics – ECG digitalization and «Smart-ECG» implementation with analysis of ranolasine efficiency, optimization of treatment of ST segment elevation syndrome. Purpose – to introduce ECG digitalisation and the program «Smart ECG» to evaluate the effectiveness of ranolasine and to optimize the treatment of ST segment elevation syndrome. Material and methods. We examined 40 patients with Q-MI (STEMI), admitted to regional clinical cardiology center in Chernivtsi, were instituted basic therapy according to the modern recommendations which contained interventional treatment with restoration of patency of a heart attack-conditioned coronary artery, double antiplatelet therapy, statins, β- adrenergic blocker, angiotensin-converting enzyme inhibitors, aldosterone antagonists with edition of ranolasine (group I, 30 patients diagnosed STEMI). Control - group II, 10 patients STEMI, who received basic therapy without addition of ranolasine. Results. Own results allow us to determine the positive effect of ranolazine on stabilization of the studied indicators of ECG digitalization according to the heart rate variability (SDNN) and QT variability (dQT), phenomena of the phase of repolarization («angle QRS-T» and “ST slope”), the first derivative of ECG ratio of maximum velocity of the differentiated deflection T and the definition of quality of life according to the EQ-5D-3L questionnaire, which partially presents the world approach. Conclusion. Analog scale EQ–VAS indicates a positive effect of Ranolazine on the quality of life of patients diagnosed with STEMI. Ranolasine (STEMI diagnosed patients) has positive influence on the markers of electrical myocardial instability and its ischemia - as evidenced: decreasing of the heart rate, probability of cases of SDNN decrease, depression of QT and maybe increase of ratio of maximum velocity for differentiated deflection T.

IMPROVEMENT OF APPROACHES AND METHODS OF TURBULENT FLOW THEORY IN THE PIPES

Abstract. The article consideres the analysis of the literature about the development of the water turbulent flow theory in the pipes. According to the results of analysis and theoretical studies, we obtained mathematical models. These models described the kinematic structure of the water turbulent flow in the pipes for different regions of turbulence. For the first time, the hypothesis was accepted that the dependence obtained from the Navier-Stokes differential equation for constructing the velocity profile in the laminar regime is suitable for calculating the average velocities in the turbulent regime of flow, but for this, it is necessary to replace the molecular kinematic viscosity with the total turbulent kinematic viscosity, which includes kinematic viscosity on the inner surface of the pipe and turbulent kinematic viscosity , which occurs due to the movement of masses from one layer into another, as recommended in J.V. Boussinesq. Based on experimental data I. Nikuradze and F.O. Shevelev, we obtained a distribution of the total kinematic viscosity in the pipes, including the kinematic viscosity on the pipe inner surface and the kinematic turbulent viscosity. For the first time, we used the kinematic viscosity distribution equation in the pipes and obtained the averaged velocity profile equation. This equation corresponds to the boundary conditions on the pipe inner surface and on the axis of the pipe. The equation of maximum averaged velocity, the equation of distance from the axis of the pipe to the points having average velocity, the equation of the ratio of maximum velocity to average velocity was obtained. For the first time, the equation of the tangent stresses components ( , ) and the tangent stresses equation in radial coordinates ( ) were obtained. The equation of the maximum value of the tangent stresses located on the inner surface of the pipe was obtained. The tangent stresses assume a zero value on the pipe axis. The equation of the vortex components ( , ) was obtained. We have shown that vortex lines are concentric circles whose centers are located on the pipe axis. The equation of angular velocity of flow particles rotation relative to the vortex lines was obtained. The maximum value of the particle rotation angular velocity on the pipe inner surface is determined. It decreases monotonically to zero on the axis of the pipeline. It is zero on the pipe axis. In this article, all equations reveal the kinematic structure of the water flow. We described these equations by the Reynolds number and the pipe friction factor. Such equations are adopted to show the dependencies between the regimes and the flow kinematic structure. These equations make it possible to calculate the distribution profile of the total kinematic viscosity, averaged velocity, tangential stresses and angular velocity of flow particle rotation.

Improvement of transport phenomena and COD removal through the design of manifolds in membrane aerated biofilm reactors for sewage treatment

The membrane aerated biofilm reactor (MABR) has demonstrated a huge potential in wastewater treatment plants (WWTPs) due to biofilm stratification and high oxygen transfer efficiency. However, an inappropriate design can negatively impact hydrodynamic and mass transfer, hampering the reactor performance. This work is intended to enhance these phenomena through a rational design of inlet flow distributors (IFD) using computational fluid dynamics (CFD) and mass-transfer simulations. Different IFDs are analyzed at macro and micromixing levels using the residence time distribution (RTD) test and CFD, respectively. It is found that the computed RTD curves agree with experimental data with an error <5 %. The conical wall distributor generates the most homogeneous velocity in the entire reaction zone (membrane zone). The maximum velocity ratio between the channeling and stagnant zones presents a diminution of ∼70 %, and an increment of ∼11.7 % on the chemical oxygen demand (COD) removal if compared against the MABR without IFD, during the sewage treatment. Results show an acceptable agreement of simulations and experimental data, indicating that this approach is satisfactory to conduct a rational design of this type of reactor.

A Pathological Clarification of Sepsis-Associated Disseminated Intravascular Coagulation Based on Comprehensive Coagulation and Fibrinolysis Function.

The functional dynamics of coagulation and fibrinolysis in patients with disseminated intravascular coagulation (DIC) vary due to the pathology and severity of various underlying diseases. Conventional measurements of hemostasis such as thrombin-antithrombin complex, plasmin-α2-plasmin-inhibitor complex, and fibrinogen-fibrin degradation products may not always reflect critical pathophysiologic mechanisms in DIC. This article aims to clarify the pathology of sepsis-associated DIC using assessment of comprehensive coagulation and fibrinolysis. Plasma samples were obtained from 57 patients with sepsis-associated DIC at the time of initial diagnosis. Hemostasis parameters were quantified by clot-fibrinolysis waveform analysis (CFWA) and thrombin/plasmin generation assays (T/P-GA). The results were expressed as ratios relative to normal plasma. CFWA demonstrated that the maximum coagulation velocity (|min1|) ratio modestly increased to median 1.40 (min - max: 0.10 - 2.60) but the maximum fibrinolytic velocity (|FL-min1|) ratio decreased to 0.61 (0 - 1.19). T/P-GA indicated that the peak thrombin (Th-Peak) ratio moderately decreased to 0.71 (0.22 - 1.20), whereas the peak plasmin (Plm-Peak) ratio substantially decreased to 0.35 (0.02 - 1.43). Statistical comparisons identified a correlation between |min1| and Th-Peak ratios (ρ = 0.55, p < 0.001), together with a strong correlation between |FL-min1| and Plm-Peak ratios (ρ = 0.71, p < 0.001), suggesting that CFWA reflected the balance between thrombin and plasmin generation. With |min1| and |FL-min1| ratios, DIC was classified as follows: coagulation-predominant, coagulation/fibrinolysis-balanced, fibrinolysis-predominant, and consumption-impaired coagulation. The majority of patients in our cohort (80.7%) were coagulation-predominant. A pathological clarification of sepsis-associated DIC based on the assessment of coagulation and fibrinolysis dynamics may be useful for the hemostatic monitoring and management of optimal treatment in these individuals.

Ductus venosus Doppler waveform pattern in fetuses with early growth restriction.

We aimed to assess if maximum velocities of the ductus venosus flow velocity waveform are associated with adverse outcomes in early-onset fetal growth restriction. Retrospective cohort study from two tertiary referral units, including singleton fetuses with estimated birthweight or fetal abdominal circumference ≤10th centile and absent or reversed end-diastolic velocity in the umbilical artery delivered between 26+0 and 34+0 weeks of gestation. Pulsatility index for veins, and maximum velocities of S-, D-, v- and a-waves, were measured in the ductus venosus within 24hours of birth. Logistic regression was used to describe the relation between severe neonatal morbidity or neonatal death and clinical independent predictors. The study population included 132 early-onset fetal growth restriction fetuses. Newborns with neonatal morbidity or neonatal death had significantly lower values of v/D maximum velocity ratio multiples of the median (0.86 vs 095; P=0.006) within 24hours of birth. The v/D ratio remained a significant predictor of neonatal death or severe neonatal morbidity after adjusting for gestational age and birthweight (adjusted odds ratio 0.065, 95% confidence interval 0.004-0.957). Assessment of ductus venosus v/D maximum velocity ratio might help to identify fetal growth restriction fetuses at increased risk for neonatal death or severe neonatal morbidity. Confirmation in prospective studies is necessary.

The Effect of Quadriceps Kinesio Taping on the Anaerobic Muscle Power and Anaerobic Threshold of Active Male Students

Introdution: The Purpose of this study examined the effect of Kinesio taping the quadriceps femurs muscle of active students on anaerobic muscle power (AMP) and the anaerobic threshold (AT) to analyze the functional value of taping on athletic performance capacity. Methods: Twenty eight male healthy students with a mean age of 22.02±2.2 years were enrolled in this study voluntarily and randomly divided into two groups of taping (n=13) and control (n=15) groups. The anaerobic muscle power (AMP) was measured by the Wingate test, and the anaerobic threshold of participants was measured by a dependent maximal treadmill protocol (Conconi Test) with a week gap. Kinesio tapes, 5 cm in width, were applied to quadriceps femurs muscles of participants. The anaerobic threshold was evaluated after 7 days taping, then after 7 days, the anaerobic muscle power was re-evaluated. Normality of data and homogeneity were tested by Shapiro–Wilk test. Paired sample t-test for within groups and independent t-test for between groups comparison were used to analyses the hypotheses (P≤0.05). Results: The results showed that there were significant differences between pre and posttest of total time, total distance, maximum velocity, LTP1, anaerobic capacity, maximum power and anaerobic capacity ratio after taping. There were no significant differences between pre and posttest in the control group. Conclusion: Taping of the quadriceps femurs muscle of active students was effective on the anaerobic muscle power and the anaerobic threshold, indicating its beneficial effects for athletic performance

The National Football League Combine 40-yd Dash: How Important is Maximum Velocity?

Clark, KP, Rieger, RH, Bruno, RF, and Stearne, DJ. The NFL combine 40-yard dash: how important is maximum velocity? J Strength Cond Res 33(6): 1542-1550, 2019-This investigation analyzed the sprint velocity profiles for athletes who completed the 40-yard (36.6 m) dash at the 2016 National Football League (NFL) Combine. The purpose was to evaluate the relationship between maximum velocity and sprint performance, and to compare acceleration patterns for fast and slow athletes. Using freely available online sources, data were collected for body mass and sprint performance (36.6 m time with split intervals at 9.1 and 18.3 m). For each athlete, split times were used to generate modeled curves of distance vs. time, velocity vs. time, and velocity vs. distance using a monoexponential equation. Model parameters were used to quantify acceleration patterns as the ratio of maximum velocity to maximum acceleration (vmax/amax, or τ). Linear regression was used to evaluate the relationship between maximum velocity and sprint performance for the entire sample. In addition, athletes were categorized into fast and slow groups based on maximum velocity, with independent t-tests and effect size statistics used to evaluate between-group differences in sprint performance and acceleration patterns. Results indicated that maximum velocity was strongly correlated with sprint performance across 9.1, 18.3, and 36.6 m (r of 0.72, 0.83, and 0.94, respectively). However, both fast and slow groups accelerated in a similar pattern relative to maximum velocity (τ = 0.768 ± 0.068 seconds for the fast group and τ = 0.773 ± 0.070 seconds for the slow group). We conclude that maximum velocity is of critical importance to 36.6 m time, and inclusion of more maximum velocity training may be warranted for athletes preparing for the NFL Combine.