Average Velocity Values Research Articles

Sediment Transport Dynamics Modeling of Overland Flow on Gentle Slopes Based on Flume Experiments

ABSTRACTSoil erosion is a global environmental issue, and sediment transport capacity (Tc) is critical for developing soil erosion models. This study conducted flume drainage experiments at six flow discharges (0.15, 0.25, 0.35, 0.45, 0.55, and 0.65 L s−1) and eight slope gradients (1.5, 3.0, 4.5, 6.0, 7.5, 9.0, 10.5, and 12.0°) to investigate how the Tc of gentle slopes in the northeastern hilly region of China and water erosion factors are related and to establish a Tc model of overland flow. The study demonstrated a power–law relationship between Tc, flow discharge, and slope gradient, as evidenced by a high coefficient of determination (R2; 0.94) and Nash–Sutcliffe efficiency (NSE; 0.92) values. Additionally, there was a positive correlation between Tc and average flow velocity, with R2 and NSE values of 0.86 and 0.84, respectively. Among the hydrodynamic parameters tested, the average flow velocity was determined to be the most effective Tc predictor, surpassing stream power (R2 > 0.7, NSE > 0.7), shear stress (R2 > 0.6, NSE > 0.6), and unit stream power (R2 < 0.5, NSE < 0.5). These findings lay the foundation for developing process‐based sediment transport models for gentle slopes in the northeastern hilly regions of China.

Rapid Response of Daphnia magna Motor Behavior to Mercury Chloride Toxicity Based on Target Tracking.

A rapid and timely response to the impacts of mercury chloride, which is indispensable to the chemical industry, on aquatic organisms is of great significance. Here, we investigated whether the YOLOX (improvements to the YOLO series, forming a new high-performance detector) observation system can be used for the rapid detection of the response of Daphnia magna targets to mercury chloride stress. Thus, we used this system for the real-time tracking and observation of the multidimensional motional behavior of D. magna. The results obtained showed that the average velocity (v¯), average acceleration (a¯), and cumulative travel (L) values of D. magna exposed to mercury chloride stress changed significantly under different exposure times and concentrations. Further, we observed that v¯, a¯ and L values of D. magna could be used as indexes of toxicity response. Analysis also showed evident D. magna inhibition at exposure concentrations of 0.08 and 0.02 mg/L after exposure for 10 and 25 min, respectively. However, under 0.06 and 0.04 mg/L toxic stress, v¯ and L showed faster toxic response than a¯, and overall, v¯ was identified as the most sensitive index for the rapid detection of D. magna response to toxicity stress. Therefore, we provide a strategy for tracking the motile behavior of D. magna in response to toxic stress and lay the foundations for the comprehensive screening of toxicity in water based on motile behavior.

Shear-Wave Elastography Gradient Analysis of Newly Diagnosed Breast Tumours: A Critical Analysis.

A better understanding of the peritumoral stroma changes due to tumour invasion using non-invasive diagnostic methods may improve the differentiation between benign and malignant breast lesions. This study aimed to assess the correlation between breast lesion differentiation and intra- and peritumoral shear-wave elastography (SWE) gradients. A total of 135 patients with newly diagnosed breast lesions were included. Intratumoral, subsurface, and three consecutive peritumoral SWE value measurements (with three repetitions) were performed. Intratumoral, interface, and peritumoral gradients (Gradient 1 and Gradient 2) were calculated using averaged SWE values. Statistical analysis included descriptive statistics and an ordinary one-way ANOVA to compare overall and individual gradients among Breast Imaging-Reporting and Data System (BI-RADS) 2, 3, and 5 groups. Malignant tumours showed higher average SWE velocity values at the tumour centre (BI-RADS 2/3: 4.1 ± 1.8 m/s vs. BI-RADS 5: 4.9 ± 2.0 m/s, p = 0.04) and the first peritumoral area (BI-RADS 2/3: 3.4 ± 1.8 m/s vs. BI-RADS 5: 4.3 ± 1.8 m/s, p = 0.003). No significant difference was found between intratumoral gradients (0.03 ± 0.32 m/s vs. 0.0 ± 0.28 m/s; p > 0.999) or gradients across the tumour-tissue interface (-0.17 ± 0.18 m/s vs. -0.13 ± 0.35 m/s; p = 0.202). However, the first peritumoral gradient (-0.16 ± 0.24 m/s vs. -0.35 ± 0.31 m/s; p < 0.0001) and the second peritumoral gradient (-0.11 ± 0.18 m/s vs. -0.22 ± 0.28 m/s; p = 0.037) were significantly steeper in malignant tumours. The AUC was best for PTG1 (0.7358) and PTG2 (0.7039). A threshold value for peritumoral SWI PT1 above 3.76 m/s and for PTG1 below -0.238 m/s·mm-1 indicated malignancy in 90.6% of cases. Evaluating the peritumoral SWE gradient may improve the diagnostic pre-test probability, as malignant tumours showed a significantly steeper curve of the elasticity values in the peritumoral stroma compared to the linear regression with a relatively flat curve of benign lesions.

The impact of V-flow on preoperative diagnosis of thyroid tumors: individually and as part of multimodal sonographic imaging.

V-flow is a dynamic ultrasound technique that visualizes perfusion patterns by displaying dynamic arrows that change in response to the flow of erythrocytes. Furthermore, it provides quantitative values for the maximum and mean velocity of blood flow as well as a percentage value for turbulence. The aim was to enhance the preoperative diagnostic accuracy of thyroid lesions by combining V-flow with established ultrasound modes.B-mode, CCDS, elastography, CEUS, and V-flow were performed on 101 patients. After the ultrasound examination, every nodule was confirmed as benign or malignant via histopathology. The Kruskal-Wallis test, ROC curve, and binary logistic regression were used for the statistical analysis.93 benign regressive thyroid nodules and 8 carcinomas were included in this study. The average mean velocity value for benign lesions was measured at 19.5 cm/s and at 10.7 cm/s for malignant lesions (p = 0.039). The average turbulence percentage was 26.1% for benign nodules and 46.7% for carcinomas (p = 0.016). Carcinomas exhibited a slower and more turbulent perfusion pattern compared to benign tumors. A V-flow-centered system achieves a sensitivity of 100.0% and a specificity of 84.9% in predicting malignancy. This system could have reduced the number of unnecessary thyroid surgeries for benign lesions in our patient group by 70%.The capillary perfusion of thyroid nodules represents a significant indicator of its status. By analyzing the velocity and turbulence level of microvascular blood flow, V-flow offers promising prospects for accurately distinguishing between benign and malignant thyroid lesions. When integrated into a comprehensive multimodal sonographic imaging approach, V-flow further enhances diagnostic accuracy. · V-flow allows for qualitative and quantitative analysis of microvascular perfusion. · Malignant tumors are associated with slower and more turbulent microvascular hemodynamics. · Combining V-flow with other ultrasound modes eases the diagnosis of thyroid carcinomas. · Brandenstein MK, Zhang L, Scharf G et al. The impact of V-flow on preoperative diagnosis of thyroid tumors: individually and as part of multimodal sonographic imaging. Fortschr Röntgenstr 2024; DOI 10.1055/a-2350-0107.

Analysis of cooling loads and air circulation in the passenger compartment of the CR400AF fast train trailer car

The air conditioning system is a system that regulates air circulation and air temperature on the train. The temperature standard for fast train passengers is in accordance with Permen No. 7th year 2022 is 22°C - 26°C. To achieve this temperature, a cooling system is needed that is suitable for the cooling load. This research was conducted on the CR400AF fast train trailer car with the aim of knowing the factors that influence cooling loads, calculating and analyzing cooling loads which are used as a reference in determining air conditioning technical specifications, as well as analyzing air circulation that affects air humidity. The data analysis method used is the quantitative data analysis method. This method is carried out by collecting primary and secondary data to be used as a basis for calculations in answering the problem formulation. Data analysis was carried out by calculating the OTTV (Overall Thermal Transfer Value) according to SNI 03-6389-2000, calculating the cooling load using the CLTD (Cooling Load Temperature Difference) method according to SNI 03-6572-2001, and carrying out an air circulation test referring to Permen No. . 7 of 2022. From the results of the analysis and calculations, the OTTV value is 15.6 Watt/m2. Room eligibility standards according to SNI 03-6389-2000 standards are OTTV values not greater than 45 Watt/m2. The internal cooling load is 15,010 W, the external load and ventilation is 22,688.92 W, the total cooling load is added 10% safety factor of 41.47 kW, the cooling capacity of the AC unit based on technical specifications is 45kW. The average value of air flow velocity during the air circulation test is 0.3 m/s. according to Ministerial Regulation No. 7 of 2022 maximum air circulation speed of 0.5 m/s. From several analysis and calculation results, it can be concluded that the passenger space of the CR400AF fast train trailer car is standard and feasible to operate

Vertical transport velocity of fine particles of aluminum smelter emissions

In this study, the average values of vertical velocity of particles emitted from an aluminum smelter in the surface layer of the atmosphere were estimated using a semi-empirical method. The method is based on regression analysis of the horizontal profile of pollutants measured along the selected direction using moss bioindicators. The selection of epiphytic mosses Sanionia uncinata was carried out in 2013 in the zone of influence of a metallurgical industry enterprise in the city of Kandalaksha, Murmansk region. The concentrations of As, Si, Ni, Zn, Ti, Cd, Na, Pb, Co, K, Ba, Ca, Mg, Mn, Sr, Fe, Al, V, Cr, Cu were determined using atomic emission spectrometry. The conducted assessments showed that the average particle velocity toward the Earth’s surface, when considering large spatial and temporal scales, is tens of times higher than gravitational settling velocities.

Research on the Characteristics of Flow Velocity of a Piped Car when Starting in a Straight Pipe Section under Different Loads

It is of great significance to explore the flow velocity characteristics of piped cars when they are started under different loads. In this paper, the flow velocity characteristics of the water flow around a piped car when it is started in the straight pipe section are studied through physical experiments. The masses of the piped cars are 1.5 kg, 1.9 kg, and 2.3 kg, respectively. The results show that, with the increase in the load of the pipeline car, the axial flow velocity in the front section increases, the absolute values of radial flow velocity and circumferential flow velocity increase, and the gradient of flow velocity increases. The positive radial flow velocity and negative circumferential flow velocity regions increase, and the distribution of positive and negative radial flow velocities and circumferential flow velocities is obvious. The gradients of axial, radial, and circumferential flow velocities in the annular section all increase, and the contour spacing becomes smaller and more densely distributed. The absolute values of the radial and circumferential flow velocities increase. The regional demarcation of axial flow velocity in the rear section is more obvious, and the average value of axial flow velocity in the high-flow-velocity area behind the vehicle increases. Additionally, the gradient of flow velocity increases. The absolute values of radial velocity and circumferential velocity increase, the gradient of velocity increases, and the velocity distribution is obviously regional. This study supplements and improves the theoretical study of a piped car when it is started and has certain reference value for the research and application of the hydraulic transport technology of the barrel-loading pipeline.

An Investigation on Hydraulic Aspects of Rectangular Labyrinth Pool and Weir Fishway Using FLOW-3D

Two different arrangements of the weir (i.e., straight weir and rectangular labyrinth weir) were used to evaluate the effects of geometric parameters such as weir shape, weir spacing, presence of an orifice at the weir, and bed slope on the flow regime and the relationship between discharge and depth, variation and distribution of depth-averaged velocity, turbulence characteristics, and energy dissipation at the fishway. Computational fluid dynamics simulations were performed using FLOW-3D® software to examine the effects on flow conditions. The numerical model was validated by comparing the calculated surface profiles and velocities with experimentally measured values from the literature. The results of the numerical model and experimental data showed that the root-mean-square error and mean absolute percentage error for the surface profiles and normalized velocity profiles of plunging flows were 0.014 m and 3.11%, respectively, confirming the ability of the numerical model to predict the flow characteristics of the pool and weir. A plunging flow can occur at values of L/B = 1.83 (L: distance of the weir, B: width of the channel) and streaming flow at L/B = 0.61 for each model. The rectangular labyrinth weir model has larger dimensionless discharge values (Q+) than the conventional model. For the conventional weir and the rectangular labyrinth weir at submerged flow, Q is proportional to 1.56 and 1.47h, respectively (h: the water depth above the weir). The average depth velocity in the pool of a conventional weir is higher than that of a rectangular labyrinth weir. However, for a given discharge, bed slope, and weir spacing, the turbulent kinetic energy (TKE) and turbulence intensity (TI) values are higher for a rectangular labyrinth weir compared to conventional weir. The conventional weir has lower energy dissipation than the rectangular labyrinth weir. Lower TKE and TI values were observed at the top of the labyrinth weir, at the corner of the wall downstream of the weir, and between the side walls of the weir and the channel wall. As the distance between the weirs and the bottom slope increased, the average depth velocity, the average value of turbulent kinetic energy and the turbulence intensity increased, and the volumetric energy dissipation in the pool decreased. The presence of an opening in the weir increased the average depth velocity and TI values and decreased the range of highest TKE within the pool, resulted in larger resting areas for fish (lower TKE), and decreased the energy dissipation rates in both models.

Prevalence of Chlamydophila spp. and Canid herpesvirus-1 in Polish dogs.

Chlamydophila spp. affect Leydig and Sertoli cells by dysregulating spermatogenesis, inducing apoptosis and sperm DNA fragmentation, as well as benign prostate hyperplasia. Canid herpes virus 1 (CHV-1) infection in male dogs is manifested by lesions on the base of the penis and foreskin. There is a lack of information on the influence of these microorganisms on the quality of canine semen. Seroprevalence of Chlamydophila spp. (55%-61%) and CHV-1 (22%-81%) in Europe is high. The prevalence of Chlamydophila spp. and CHV-1 has been evaluated using polymerase chain reaction (PCR) only in Sweden and Croatia, respectively. No positive samples were detected in either case. The aim of this study was to evaluate the epidemiological situation in Polish male dogs (PMDs) to provide a solution to limit the spread of these microorganisms using assisted reproduction techniques or elimination from the reproduction of CHV-1 carriers. In addition, we assessed the semen quality of Chlamydophila spp. carriers and CHV-1 carriers. Cotton swabs were collected from prepuce or semen from each dog (n = 130). Real-time PCR for Chlamydophila spp. and CHV-1, as well as semen analysis, was performed using the computer-assisted semen analysis system. To the best of our knowledge, this is the first report of Chlamydophila spp. infection in PMD confirmed by real-time PCR. All parameters, except progressive movement in Chlamydophila semen carriers, were normal. The average velocity values for a dog with Chlamydia are detailed. No CHV-1 was detected. The results achieved should be verified on the basis of a larger number of studies. However, the high prevalence of these pathogens in the PMD population has not been established.

Methane Exchange Flux Monitoring between Potential Source Sewage Inspection Wells and the Atmosphere Based on Laser Spectroscopy Method

Greenhouse gas emissions are changing the climate and affecting human activities. In cities, the anaerobic environment in sewage inspection wells produces CH4, which is exchanged with the atmosphere and causes pollution. Moreover, although the number of inspection wells has increased with the development of cities, people have not paid enough attention to this potential source of CH4 and ignored it in the statistics of greenhouse gas inventories. Conventional gas monitoring methods like gas chromatography are complex and expensive. Based on the portable TDLAS CH4 sensor developed by our team, combined with a gas velocity analyser, we realised in situ continuous flux monitoring. We corrected the effect of temperature on the results according to the theory of infrared thermometry. We showed that the measurement results of the sensor fluctuate within the range of ±0.1 ppm of the measured standard gas concentration. We also verified its repeatability and ensured its reliability in field applications by comparing its results with the results of gas chromatography analysis. In addition to flux monitoring, based on the monitoring data of 56 inspection wells in the study area, the average concentration was estimated using the Bootstrap method, and combined with the average value of gas velocity, the average flux was estimated to be 2.19 × 10−6 mol/s, and the daily exchange mass was 3.03 g CH4 d−1. Combined with information such as the length of sewage pipes, we estimate that the annual CH4 exchange mass in the city is about 5.49 × 105 kg CH4 yr−1. This monitoring method will help us to understand climate change and improve greenhouse gas inventories.

Evolution of temporal and frequency characteristics of spherical photon density waves in scattering media

The paper reports on the numerical study of temporal characteristics, frequency and phase responses of the photon density waves generated by a point-sized source in scattering media with different scattering anisotropy and absorption index. The study is performed with time-resolved Monte-Carlo simulations for a wide range of medium optical properties covering values typical for aerosols and sea water. We demonstrate that although the normalized pulse delay increases monotonically with distance in the course of propagation in the medium, for particular sets of optical properties its normalized width shows a non-monotonous trend with a maximum corresponding to distances where ballistic and multiply scattered photons give comparable contribution to the irradiance field. In the frequency responses of photon density waves for certain combinations of optical properties at particular distances a deep minimum is formed, also associated with the interference of partial waves. The dimensionless frequency corresponding to this minimum monotonically increases with the increase in anisotropy factor. Dependencies of local and averaged phase and group velocities on distance derived from phase responses revealed a formation of a minima in local group velocities dependencies with further increase to the average velocity values at higher distances, which is also associated with relative contribution of low- and multiply scattered photons. The revealed dependencies can be useful for verifying the analytical models of nonstationary radiation transfer and directly for assessing the achievable parameters of optical systems for various purposes operating in natural scattering media, such as the atmosphere and sea water.

Impact of endolymphatic hydrops on the function of the horizontal canal during caloric stimulation in Ménière's disease.

When a dizzy patient with episodic vertigo has an abnormal caloric and a normal video head impulse test (vHIT), this caloric-vHIT dissociation provides vital information for a diagnosis of Ménière's disease (MD). Endolymphatic hydrops (EH), a histological marker of MD, is hypothesized to be involved in the caloric-vHIT dissociation in MD through hydropic duct distension of the horizontal semicircular canal (SC). This study was designed to determine the impact of EH on the function of horizontal SC during caloric stimulation. Caloric test and vHIT were used to evaluate the function of horizontal SC every six months, annual magnetic resonance imaging (MRI) was used to evaluate the degree of EH size in the vestibule, and monthly vertigo and hearing evaluation was done for 12months. EH shrinkage was defined as the size change of vestibular EH from significant to none. Among 133 MD patients evaluated for eligibility, 67 patients with caloric-vHIT dissociation entered the study. Fifteen participants had EH shrinkage (G-I), while 52 participants had no remarkable EH change (G-II). Average values (IQR) of the maximum slow phase velocity in G-I and G-II were 29.6 (13.0-34.0) and 25.9 (17.3-31.3), respectively, at baseline, 26.1 (9.0-38.0) and 23.6 (18.0-28.3) at 12months. Two-factor repeated-measures ANOVA showed no significant differences between the groups (P = 0.486). The values of vestibulo-ocular reflex gain of the horizontal SC in G-I and G-II remained above 0.8 during the study period. EH detected by MRI shows limited correlation with caloric stimulation results.

Fast-rotating Blue Straggler Stars in the Globular Cluster NGC 3201* *Based on observations collected at the Clay Magellan Telescope, located at Las Campanas Observatory (Chile).

We used high-resolution spectra acquired with the Magellan Telescope to measure radial and rotational velocities of approximately 200 stars in the Galactic globular cluster NGC 3201. The surveyed sample includes blue straggler stars (BSSs) and reference stars in different evolutionary stages (main-sequence turnoff, subgiant, red giant, and asymptotic giant branches). The average radial velocity value (〈V r 〉 = 494.5 ± 0.5 km s−1) confirms a large systemic velocity for this cluster and was used to distinguish 33 residual field interlopers. The final sample of member stars has 67 BSSs and 114 reference stars. Similarly to what is found in other clusters, the totality of the reference stars has negligible rotation (< 20 km s−1), while the BSS rotational velocity distribution shows a long tail extending up to ∼200 km s−1, with 19 BSSs (out of 67) spinning faster than 40 km s−1. This sets the percentage of fast-rotating BSSs to ∼28%. Such a percentage is roughly comparable to that measured in other loose systems (ω Centauri, M4, and M55) and significantly larger than that measured in high-density clusters (as 47 Tucanae, NGC 6397, NGC 6752, and M30). This evidence supports a scenario where recent BSS formation (mainly from the evolution of binary systems) is occurring in low-density environments. We also find that the BSS rotational velocity tends to decrease for decreasing luminosity and surface temperature, similarly to what is observed in main-sequence stars. Hence, further investigations are needed to understand the impact of BSS internal structure on the observed rotational velocities.

Normative Values forPupillary Light Reflex Metrics Among Healthy Service Academy Cadets.

Assessments of the pupil's response to light have long been an integral part of neurologic examinations. More recently, the pupillary light reflex (PLR) has shown promise as a potential biomarker for the diagnosis of mild traumatic brain injury. However, to date, few large-scale normative data are available for comparison and reference, particularly, in military service members. The purpose of this study was to report normative values for eight PLR measurements among healthy service academy cadets based on sex, age, sleep, race, ethnicity, anisocoria, and concussion history. Freshmen entering a U.S. Service Academy completed a quantitative pupillometric assessment in conjunction with baseline concussion testing. PLR measurements were conducted using a Neuroptics PLR-3000 with a 121µW light stimulus. The device measured maximum and minimum pupil diameter (mm), latency (time to maximum pupil constriction post-light stimulus [s]), peak and average constriction velocity (mm/s), average dilation velocity (mm/s), percentage pupil constriction, and T75 (time for pupil re-dilation from minimum pupil diameter to 75% maximum diameter [s]). During baseline testing, cadets also reported concussion history (yes and no) and hours slept the night before (<5.5 and ≥5.5). Normative values for each PLR measurement were calculated as mean ± SD, percentiles, and interquartile range. Mann-Whitney U tests were used to assess differences based on sex, concussion history, ethnicity, and hours slept for each PLR measurement. Kruskall-Wallis testing was used to assess differences based on age, race, and anisocoria. Alpha was set at .05 and nonparametric effect sizes (r) were calculated for statistically significant results. Effect sizes were interpreted as no effect (r < .1), small (r ≥.1-<.3), medium (r ≥.3-<.5), or large (r ≥ .5). All procedures were reviewed and approved by the local institutional review board and the U.S. Army Human Research Protection Office before the study was conducted. Each subject provided informed consent to participate in the study before data collection. Of the 1,197 participants baselined, 514 cadets (131 female; 18.91 ± 0.96years) consented and completed a valid baseline pupillometric assessment. Eighty participants reported at least one previous concussion and participants reported an average of 5.88 ± 1.63 h slept the previous night. Mann-Whitney U results suggest females had larger initial (z = -3.240; P = .001; r = .10) and end pupil diameter (z = -3.080; P = .002; r = .10), slower average dilation velocity (z = 3.254; P = .001; r = .11) and faster T75 values (z = -3.342; P = .001; r = .11). Age, sleep, and race stratified by sex, also displayed a significant impact on specific PLR metrics with effect sizes ranging from small to medium, while ethnicity, anisocoria, and concussion history did not display an impact on PLR metrics. This study provides the largest population-specific normative values for eight PLR measurements. Initial and end pupil diameter, dilation velocity, and the T75 metrics differed by sex; however, these differences may not be clinically significant as small effect size was detected for all metrics. Sex, age, sleep, and race may impact specific PLR metrics and are worth consideration when performing PLR assessments for mild traumatic brain injury management.

Conditioned medium and secretome from epididymal epithelial cell cultures improve sperm kinetics and capacitation.

Sperm maturation occurs in the epididymis through interactions with existing molecules inside the lumen. However, the mechanism of epididymis molecular transfer is currently unclear. This study was aimed to determine the necessity of the epididymal epithelial cells (EECs) in the process of sperm maturation in terms of sperm kinetics and tyrosine phosphorylation. A true experimental research design was used in this study. The medium tested was a primary culture of mice caput epididymal cells (cells and culture medium), conditioned medium (CM) (supernatant of EECs), and secretome (CM filtered at 0.22 μm). Sperm was cocultured in EEC culture, CM, and secretome for 1, 2, 3, or 4 h. The original culture medium was used as the control. Sperm kinetic analysis was performed after the indicated times using computer-assisted sperm analysis, and tyrosine phosphorylation was detected using the Western blot technique. A primary culture of caput EECs was successfully generated. The results showed increased sperm motility and progressive movement after 3 h of incubation (p < 0.05). There was a significant decrease in the average path velocity (VAP) values after 4 h of incubation (p < 0.05), but there was no significant change in the 1, 2, and 3 h incubation groups. The EEC culture-CM and secretome groups showed a significant increased progressivity and VAP percentage values compared with the control medium (p < 0.05). In terms of percentage motility, the culture and CM groups were significantly different from the control medium, but the secretome group was not. The sperm kinetics of sperm cultured in CM, secretome, and EEC were significantly increased after 3 h of incubation, suggesting that CM and secretome can be used to replace EECs, especially when analyzing molecules secreted by the epididymal epithelium during sperm maturation. The results of this study highlight the potential of CM and secretome as therapy mediums for sperm kinetic abnormalities.

The synergistic hydrogen production of bicellular fermentation systems and fluid dynamics simulation in reactor under stirring

The effect of stirring (200–800 rpm) on the synergistic fermentation hydrogen production by bicellular system consisted of Bacillus cereus (A) and Brevundimonas naejangsanensis (B) was investigated. Results indicated that hydrogen yield is the highest (1.36 mol H2/mol glucose) at 800 rpm for bicellular system and its efficiency is 1.3 and 1.4 times higher than the highest value obtained from the single fermentation of Strain A at 800 rpm and Strain B at 400 rpm, respectively. Butyric acid-type fermentation is dominated during the co-cultured fermentation at preferred stirring speed. Results via computational fluid dynamics (CFD) simulations showed that the area-weighted average value of velocity (m/s) on the cross section (y = 4.365 mm) is 0.104, 0.198 and 0.358 for the co-cultured fermentation under different stirring speeds, respectively. Major hydrodynamic parameters increased with the increasing stirring speed. This preliminarily revealed that hydrogen yield is seriously limited by the main accumulated metabolites.

Experimental study on velocity distribution and bed load transport in compound channels: Effect of the floodplain’s wall parallel with the meandering main channel

In this study, the effect of the floodplain’s parallel wall with a compound meandering main channel over the hydraulics flow has been analyzed experimentally. A constant sinuosity factor of 1.3 and relative flow depths of 0.3 to 0.55 were considered to illustrate the effect of the hydraulic parameters on the variations of the velocity components. Velocity components were measured by ADV velocimeter at seven cross sections with angles of zero, 30, and 60 degrees and mesh size of 2 cm × 2 cm. Furthermore, a laser meter measured the topographies of the sediment bed in the 33 cross-sections with an angle difference of 5 degrees to the bend apex. The results showed that in lower relative depths, due to vortexes and high turbulence intensity, the ability of flood damage will be more eminent. The CS04 section with the least longitudinal and transverse changes in the water level is the best position for hydraulic investigation of the meandering rivers. The left bank in sections CS03 to CS07 will be the place of deposit of sediment in nature with the formation of the stagnation area. The velocity of (Ud(fp-inner)) is 3 to 5 times higher than (Ud(fp-outer)). For this cause, the flow in the outer bank, unlike the inner bank, has a reduced effect on the flow velocity in the main channel. Increasing the relative depth, the ratio (Ud(mc)/Ud(T)) and (Ud(fp)/Ud(T)) decreased and increased, respectively. Therefore, the average velocity values in the main channel and the floodplains reached the average velocity of the whole section. The flow velocity in the main channel is always higher than in the floodplains, and the ratio (Ud(fp)/Ud(mc)) is less than one. The variation trend in the average values of bed shear stress, turbulence kinetic energy (TKE) and average kinetic energy (MKE) was decreased with increasing relative flow depth. Both factors of relative depth and Froude number will affect the location of the occurrence of the maximum values of velocity, bed shear stress, maximum depth hole and the peak of the sedimentary hill.

The Influence of Obesity in the Autonomic Nervous System Activity in School-Aged Children in Northern Portugal: A Cross-Sectional Study.

Obesity is one of the most prevalent chronic diseases in childhood, being an important public health issue. Excessive weight has been associated with autonomic dysfunction but the evidence in children is scarce. Therefore, the aim of this study was to assess the effect of overweight and obesity on the autonomic nervous system activity, in children. Data from a cross-sectional study of 1602 children, aged 7 to 12 years, was used and 858 children were included in the analysis. Body mass index was calculated and classified according to criteria of the World Health Organization (WHO), Centers for Disease Control and Prevention (CDC) and the International Obesity Task Force (IOTF). Body composition was characterized by bioelectrical impedance. Linear regression models were used to determine the association between body mass index, body composition and the autonomic nervous system activity, assessed by pupillometry. Average dilation velocity was higher among children with obesity, according to the CDC and percentage of body fat criteria (β = 0.053, 95% CI = 0.005 to 0.101 and β = 0.063, 95% CI = 0.016 to 0.109, respectively). The same trend was observed for WHO and IOTF criteria (β = 0.045, 95% CI = -0.001 to 0.091, and β = 0.055, 95% CI = -0.001 to 0.111, respectively). CDC and WHO body mass index z-scores were also positively associated with the values of average dilation velocity (rs = 0.030, p = 0.048; and rs = 0.027, p = 0.042, respectively). Our findings suggest an association between body mass and changes in the autonomic activity, Moreover, this study provides proof of concept for interventions targeting the prevention/treatment of obesity in children that may offer some benefit in re-establishing the balance of the autonomic nervous system, and subsequently preventing the consequences associated with the autonomic nervous system dysfunction.

Analysis of factors influencing the values of parameters of intraoperative flowmetry of coronary bypass grafts: retrospective single-center cross-sectional study

Оbjective. This study determines the factors that can affect the value of the parameters of intraoperative flowmetry of coronary bypass grafts.&#x0D; Material and methods. TTFM is a routine procedure accompanying coronary artery bypass grafting at the Federal State Budgetary Institution FTSSSh (Penza). This retrospective study included 995 consecutive patients who underwent isolated coronary artery bypass grafting of the left coronary artery. The exclusion criteria were damage to the right coronary artery bed, the emergency nature of the operation, and the combined pathology of the valvular apparatus. Patients who underwent anastomosis revision due to flowmetry parameters changes were also excluded from the study. Intraoperative assessment of coronary artery bypass grafts was performed using VeryQ and MiraQ MediStim flowmeters (Norway).&#x0D; Results. A total of 1733 arterial and 479 venous grafts were evaluated. The following factors influenced the average volumetric blood flow velocity value: composite shunting of the border stenosis increases the chance of reducing the volumetric blood flow below the threshold value by 1.841 times (OR=1.841; p=0.018), the combination of occlusion and borderline stenosis with composite shunting increases the chance of reducing the volumetric blood flow velocity by 3.91 times (OR=3.91; p=0.041), an increase in the diameter of the bypassed artery by 1.0 mm reduces the chance of a decrease in blood flow volume velocity by 53.7% (OR=0.423; p=0.05).&#x0D; Conclusion. The following factors influence the peripheral resistance index: coronary artery diameter (OR=0.21; p=0.001), degree of artery proximal stenosis (OR=0.987; p=0.034), the vascular wall condition (OR=2.25; p=0.05), type of conduit used (OR=0.298; p=0.002), and shunting method (OR=1.699; p=0.017). The following factors influence the mean volumetric blood flow velocity value: bypass method (OR=1.841; p=0.018), a combination of occlusion and borderline stenosis in composite bypass grafting (OR=3.91; p=0.041), and the bypassed artery diameter (OR=0.423; p=0.423; p=0.05).

Experimental and Numerical Considerations for the Motor-Propeller Assembly’s Air Flow Field over a Quadcopter’s Arm

The aim of the paper is to validate the analytical–numerical analysis method regarding the operating regime of the propellers of a quadcopter. The research aims to mark the flow areas whose numerical results differ from the experimental ones and to investigate the possible reasons for the discrepancies between the values. The paper presents the determination of the air velocity produced by the rotational movement of a quadcopter propeller for a stationary position of the drive motor. The velocities were determined both experimentally at various points located below the propeller plane using hot-wire anemometric probes and numerically using a time-lapse simulation with a rotating sliding table. The numerical simulations carried out consisted of the determination of the time variation of the velocity distribution developed by the propeller in the rotational movement for the different operating (power) cycles of the engine. In addition, a technique that utilizes reverse engineering to determine the propeller profile, the anemometric probe calibration, and the average velocity values measured at various points below the propeller plane for engine operating regimes that range from 60 to 90% are also presented.