Maximum Linear Velocity Research Articles

Advanced water treatment using a meshed synthetic tube as biological filter media in pilot plant scale

ABSTRACT The purpose of this study is to remove suspended solids (SS) and soluble organic matter from waste water using meshed synthetic tubes, made of synthetic poly propylene fiber to allow free water flow from any direction. The capacity of 450 m3/d pilot plant was operated to treat effluent of secondary settling tank in sewage treatment plant. Removals of SS, soluble organic matter and phosphorus (w/additional chemical treatment), were monitored. As a result, maximum SS-loading rate for the plant was found 3.8 kg SS/m3 d, and operation time was limited up to 45 h, and the maximum linear velocity was found 16 m3/m2 h. The maximum SS removal for each unit reactor was 7.1 kg/cage m3. With the meshed tube biofilter, not only SS but also soluble organic matter removal and nitrification were observed. Because of its relatively fast filtration rate and high filtration capacity, it seemed to be used properly as a direct filtration.

Ecotoxicological effects of waterborne PFOS exposure on swimming performance and energy expenditure in juvenile goldfish (Carassius auratus)

The potential risks of perfluorooctane sulfonate (PFOS) are of increasing ecological concern. Swimming performance is linked to the fitness and health of fish. However, the impacts of PFOS on swimming performance remain largely unknown. We investigated the ecotoxicological effects of acute exposure to PFOS on the swimming performance and energy expenditure of juvenile goldfish (Carassius auratus). The fish were exposed to a range of PFOS concentrations (0, 0.5, 2, 8 and 32 mg/L) for 48 hr. The spontaneous swimming activity, fast-start swimming performance, critical swimming speed (Ucrit) and active metabolic rate (AMR) of the goldfish were examined after exposure to PFOS. PFOS exposure resulted in remarkable effects on spontaneous activity. Motion distance was reduced, and the proportion of motionless time increased with increasing concentrations of PFOS. However, no significant alterations in the fast-start performance-related kinematic parameters, such as latency time, maximum linear velocity, maximum linear acceleration or escape distance during the first 120 msec after stimulus, were observed after PFOS exposure. Unexpectedly, although PFOS exposure had marked influences on the swimming oxygen consumption rates and AMR of goldfish, the Ucrit of the goldfish was not significantly affected by PFOS. This may result in a noteworthy increase in the energetic cost of transport. The overall results indicate that, in contrast to spontaneous activity, underlying swimming capabilities are maintained in goldfish after short-term exposure to PFOS, but energy expenditure during the process of swimming is dramatically aggravated.

An interspecific comparison between morphology and swimming performance in cyprinids

Flow regimes are believed to be of major evolutionary significance in fish. The flow regimes inhabited by cyprinids vary extensively from still flow regimes to riptide flow regimes. To test (i) whether flow-driven swimming performance and relevant morphological differentiation are present among fish species and (ii) whether evolutionary shifts between high-flow and low-flow habitats in cyprinids are associated with evolutionary trade-offs in locomotor performance, we obtained data on both steady and unsteady swimming performance and external body shape for 19 species of cyprinids that typically occur in different flow regimes (still, intermediate and riptide). We also measured the routine energy expenditure (RMR) and maximum metabolic rate (MMR) and calculated the optimal swimming speed. Our results showed that fish species from riptide groups tend to have a higher critical swimming speed (Ucrit ), maximum linear velocity (Vmax ) and fineness ratio (FR) than fish from the other two groups. However, there was no correlation between the reconstructed changes in the steady and unsteady swimming performance of the 19 species. According to the phylogenetically independent contrast (PIC) method, the Ucrit was actively correlated with the MMR. These results indicated that selection will favour both higher steady and unsteady swimming performance and a more streamlined body shape in environments with high water velocities. The results suggested that steady swimming performance was more sensitive to the flow regime and that for this reason, changes in body shape resulted more from selective pressure on steady swimming performance than on unsteady swimming performance. No evolutionary trade-off was observed between steady and unsteady swimming performance, although Ucrit and MMR were found to have coevolved. However, a further analysis within each typically occurring habitat group suggested that the trade-off that may exist between steady and unsteady swimming performance may be concealed by the effect of habitat.

A face-shear mode single crystal ultrasonic motor

We report a face-shear mode ultrasonic motor (USM) made of [011]c poled Zt ± 45° cut 0.24Pb(In1/2Nb1/2)O3-0.46Pb(Mg1/3Nb2/3)O3-0.30PbTiO3 single crystal, which takes advantage of the extremely large d36 = 2368 pC/N. This motor has a maximum no-load linear velocity of 182.5 mm/s and a maximum output force of 1.03 N under the drive of Vp = 50 V, f = 72 kHz. Compared with the k31 mode USM made of Pb(Zr,Ti)O3 (PZT), our USM has simpler structure, lower driving frequency, much higher electromechanical coupling factor, and twice power density. This USM can be used for low frequency operation as well as cryogenic actuation with a large torque.

The influence of starvation on fast-start performance of Spinibarbus sinensis

Juvenile Spinibarbus sinensis (n=48, body length, 5.86±0.10cm, 25°C) were fasted for 0, 0.5, 1, 2, 4 and 6weeks. The fast-start performances of the experimental fish were assessed using high-speed video photography and the locomotive kinematics analysis. The morphological parameters including tail height (H2), tail length (L2), lateral body area (S1), median fin area (S2), dorsal cross section area (S3) and tail cross section area (S4) were also measured using TpsDig and the Photoshop. The results showed that 6week starvation resulted in significant decreases in the escape distance (d), maximum linear velocity (Vmax) and maximum linear acceleration (amax) of center of mass in Stage 1 and Stage 2 of fast-start process (P<0.05), however there were two relatively sTable phases in the Vmax and d, during the week 1–2 (Vmax=0.67±0.06mm/ms; d=8.86±0.73mm) and week 4–6 (Vmax=0.31±0.04mm/ms; d=3.70±0.56mm). When compared with the control group (0week starvation group), only the 6week starvation group showed the significantly different response time (t) with average t=9.20±0.37ms in week 1–4. There were no significant difference in mass center turning angles at first stage (Ta1) , second stage (Ta2) and the sum of two stages (Ta(1+2)) was also not different (P>0.05). The fish did not show any directional preference for left or right during escape turning, and all of the related parameters also remained unchanged among treatment group (P>0.05). The areas of dorsal body cross-section decreased more acutely (P<0.05) than caudal body cross-section (45.4% vs 38.0%) during the entire starvation period while no significant differences were observed in both the tail height and tail length among all treatment groups (P>0.05). The results indicated that fast-start performance of juvenile S. sinensis is affected by the starvation; metabolic energy related traits such as the maximum linear velocity and the maximum linear acceleration decreased significantly after starvation; whereas traits with no direct link to metabolic energy such as the response time and turning angle remained unchanged during starvation. The lack of starvation induced change in the maneuverability of the fish suggests that fast-start ability related to escape strategy is relatively well conservative in juvenile S. sinensis.

Dimensional analysis of a planetary mixer for homogenizing of free flowing powders: Mixing time and power consumption

Powder mixing is crucial to the processing stages in many industries. However, there is still a paucity of information about the effects of process parameters on mixing efficiency. This paper investigates the homogenization of free flowing granular materials with a planetary mixer, TRIAXE®, examining the effect of the ratio of impeller rotational speeds (NR/NG) on the mixing process.First, a dimensional analysis carried out with mixing time and power consumption as target variables, established that both a Froude number and NR/NG controlled the process for the given free flowing powder mixture and planetary mixer.A further theoretical approach also suggested that these two dimensionless ratios which control hydrodynamics can be reduced to a modified Froude number providing that the maximum linear velocity achieved (uch) by the planetary mixer is introduced, replacing the dual impeller rotational speeds (NR and NG).Mixing time and power experiments validated the above hypothesis. Homogeneity tests performed in a granular media showed that the length of path achieved by the impeller governs the obtained mixing level.Finally, this work reflected that (i) dimensional analysis was also well suited to model powder homogenization with a planetary mixer. (ii) A concise set of dimensionless numbers governing mixing phenomena can be deduced through the introduction of the maximum linear velocity as obtained in previous studies on gas/liquid and miscible liquids mixing processes.

Challenging zebrafish escape responses by increasing water viscosity

Escape responses of fishes have long been studied as a model locomotor behavior in which hypothesized maximal or near-maximal muscle power output is used to generate rapid body bending. In this paper we present the results of experiments that challenged zebrafish (Danio rerio) to perform escape responses in water of altered viscosity, to better understand the effects that the fluid mechanical environment exerts on kinematics. We quantified escape kinematics using 1000 frames s(-1) high-speed video, and compared escape response kinematics of fish in three media that differed in viscosity: 1 mPa s (normal water), 10 mPa s and 20 mPa s (20 times normal water viscosity). We hypothesized that because viscosity is increased but not density there will be a different effect on kinematic variables resulting from unsteady (acceleration-dependent) hydrodynamic forces and steady (velocity-dependent) ones. Similarly, we hypothesized that the kinematics of stage 1 will be less affected by viscosity than those of stage 2, as higher angular velocities are reached during stage 1 resulting in higher Reynolds numbers. Our results showed a significant overall effect of viscosity on escape response kinematics but the effect was not in accordance with our predictions. Statistical tests showed that increasing viscosity significantly decreased displacement of the center of mass during stage 1 and after 30 ms, and decreased maximum velocity of the center of mass, maximum angular velocity and acceleration during stage 1, but increased time to maximum angular acceleration and time to maximum linear velocity of the center of mass. Remarkably, increasing water viscosity 20 times did not significantly affect the duration of stage 1 or stage 2.

The trade-off between steady and unsteady swimming performance in six cyprinids at two temperatures

The purpose of this study was to investigate whether a functional trade-off (as assessed by a negative phenotypic relationship) between steady and unsteady swimming performance exists in six selected cyprinids and whether the possible trade-off changed with temperature. We measured the critical swimming speed (Ucrit, i.e., the water speed at which a fish can no longer maintain its position or its maximum sustainable swimming speed), metabolic rate (ṀO2) and fast-start performance in juvenile grass carp (Ctenopharyngodon idellus), crucian carp (Carassius auratus), qingbo (Spinibarbus sinensis), Chinese bream (Parabramis pekinensis), common carp (Cyprinus carpio) and sharp-jaw barbel (Onychostoma sima) at 15 and 25°C. Steady swimming performance as indicated by Ucrit and unsteady swimming performance as indicated by maximum linear velocity (Vmax), maximum linear acceleration (Amax) and the escape distance during 120ms (S120ms) varied significantly among species and between temperatures (P<0.05). There was no significant relationship between steady and unsteady swimming performance at low temperature. Ucrit was positively related to Vmax at 25°C. These findings clearly demonstrated that the relationship between steady and unsteady swimming performance changed with temperature. Both steady and unsteady swimming performance increased significantly with temperature. However, the thermal sensitivity of Ucrit was negatively related to that of the fast-start variables. This result suggested that a trade-off exists in the temperature reaction norm of the two types of swimming performance among the six cyprinids.

Fluidic Behavior of Polymer Compounds in an Open-Tubular Capillary with Ternary Mixed Carrier Solvents under Laminar Flow Conditions

An open-tubular capillary chromatography is developed based on tube radial distribution of the ternary mixed carrier solvents of water-hydrophilic/hydrophobic organic under laminar flow conditions. This is called “tube radial distribution chromatography” (TRDC). Fluidic behavior of the polymer compounds, FluoSpheres (1.0 m diameter), was examined by the TRDC system. The ternary mixture of water-acetonitrile-ethyl acetate, 15:3:2 (water-rich) or 3:8:4 (organic solvent-rich) volume ratio, as a carrier solution was fed into the fused-silica capillary tube under laminar flow conditions. The peak of the FluoSpheres appeared with the apex at the maximum linear velocity and the slope of the non-Gaussian peak did not last longer than the elution time at the average linear velocity with the water-rich carrier solution. With the organic solvent-rich carrier solution FluoSpheres was eluted at near the average linear velocity.

Doppler ultrasound to detect pulpal blood flow changes during local anaesthesia

To examine whether Doppler ultrasound can detect changes in pulpal blood flow after infiltration anaesthesia. Changes in pulpal blood flow in maxillary central incisor teeth of 18 patients (mean age 26.7 years, 13 men, five women) after infiltration anaesthesia were examined. Before infiltration anaesthesia, the pulpal blood flow was measured using Doppler ultrasound. A local anaesthetic solution containing 2% lidocaine with 1:80,000 epinephrine was injected into the submucosa above the experimental tooth. The Doppler ultrasound test was carried out at 5, 10, 20, 30, 45 and 60 min after infiltration. The parameters were Vas (maximum linear velocity, cm s(-1) ), Vam (average linear velocity, cm s(-1) ) and Vakd (minimum linear velocity, cm s(-1) ), which are indicators of the level of blood flow. The mixed procedure at the 95% confidence interval was used to examine the changes in pulpal blood flow after the injection. The linear velocity profiles (Vas, Vam, and Vakd) decreased sharply 5 min after anaesthesia and then reduced continuously for 30 min. The maximum degree of blood flow reduction in Vas, Vam and Vakd was 58%, 83% and 82%, respectively. After 30 min, the linear velocities increased gradually. The Vam returned to the pre-anaesthesia state at 60 minutes but the Vas and Vakd did not recover completely. Doppler ultrasound can detect changes in pulpal blood flow after infiltration anaesthesia. In the future, Doppler ultrasound can be used as a tool for measuring pulpal blood flow.

Acute effects of endurance exercise on jumping and kicking performance in top-class young soccer players

The aim of this study was to examine the acute effects of endurance exercise on jumping and kicking performance in young soccer players. Twenty-one top-class young soccer players (16.1±0.2 years) performed a countermovement jump test and a maximal instep soccer kick test before and after running for 20 min on a treadmill at 80% of their individual maximum heart rate. Two force platforms were used to obtain the following parameters during the countermovement jump: jump height, maximum power, maximum power relative to body mass, maximum vertical ground reaction force, maximum vertical ground reaction force relative to body mass, and maximum vertical ground reaction force applied to each leg. Maximum vertical ground reaction force and maximum vertical ground reaction force relative to body mass applied to the support leg during the kicks were also calculated with a force platform. The kicking motion was recorded using a three-dimensional motion-capture system. Maximum velocity of the ball, maximum linear velocity of the toe, ankle, knee and hip, and linear velocity of the toe at ball contact during the kicks were calculated. Non-significant differences were found in the parameters measured during the countermovement jump and the maximal instep soccer kick test before and after running, suggesting that the jumping and kicking performances of top-class young soccer players were not significantly affected after 20 min treadmill running at 80% of their individual maximum heart rate.

Fast, Regional Conduit Flow to an Exceptional-Value Spring-Fed Creek: Implications for Source-Water Protection in Mantled Karst of South-Central Pennsylvania

Karst springs of Cumberland County, Pennsylvania, are important water resources, but their sources and flow paths are unknown. We traced flow in a mantled- karst groundwater system in the Great Valley section of the Valley and Ridge Physiographic Province using fluorescent dyes, with focus on Big Spring Creek. Upper Big Spring Creek is assigned High Quality/Exceptional Value status by Pennsylvania based on its high water quality and value as a multi-use resource with exceptional recreational or ecological significance. Subsurface flow followed the geologic strike after Sulpho Rhodamine B (Acid Red 52) dye was released on exposed carbonates. Subsurface flow had a maximum effective linear velocity of 2.5 km d 21 , which is 8 times greater than sodium fluorescein (Acid Yellow 73) dye released separately into a losing stream over colluvium (0.3 km d 21 ). Sulpho Rhodamine B was detected strongly 8.9 km away at Big Spring Creek's largest source spring (,250 ppt water; 50 ppb eluate), but weakly in an east source (2.5 ppb eluate). Sodium fluorescein was detected after four weeks at 0.07 to 0.15 ppb in eluate at springs at Huntsdale Hatchery, 9.5 km from release atop the colluvial mantle. Slow flow derived from losing streams on the colluvial mantle likely maintains water quality of Big Spring Creek and similar systems. However, this recharge is distant, and the flow passes below karst recharge features in the valley center, creating many opportunities for contamination. Future studies of contaminant and sediment loadings to subterranean basins and of source-water protection strategies that recognize these patterns are necessary to protect these streams.

Ball height during backswing and its influence on tenpin bowling performance

In tenpin bowling, it is common for coaches to suggest that bowlers display a higher backswing in order to generate higher peak ball velocity during swing (PBvel). This stems from the assumption that the swing is akin to a pendulum, whereby the speed of the ball is dependent on the potential energy gained from its starting height. The primary objective of this study was to ascertain whether maximum ball height (BHNorm) during backswing is related to PBvelor bowling score average (BSave). The study also compared BHNormbetween elite and backup bowlers. Participants were assigned into two groups based on their BSave over three tournaments, with those averaging above 200 pin falls placed in the elite group. There were 18 elite (M=10, F=8; BSave 213±7) and 12 backup bowlers (M=7, F=5; BSave 181±9). Ball height and velocity data were derived from Kwon3D system utilising four 100 Hz cameras. BHNormwas the vertical distance between the maximum ball height during backswing and the lowest point during swing, normalised to subject's height. PBvelwas the maximum linear forward velocity of the ball near release. Participants aimed for a strike at each of the four trials, the mean scores were used. In terms of relationship to bowling performance, BHNormhad no significant (p&lt;0.05) relationship to BSave (r=0.00) and PBvel(r=0.01). Comparisons of BHNormbetween the elite and backup group also yielded no significant differences. Contrary to the popular notion that raising the ball higher will lead to higher release velocity, the height a ball is raised during backswing does not seem to correspond with higher ball speeds, nor does it relate to better bowling scores. The latter is supported by the fact that there was no significant difference in BHNormbetween the different level bowlers. It can be suggested that the ball height during backswing is more of a choice of individual preference rather than the need to generate more ball speed.

Kinematic Comparison of Successful and Unsuccessful Instep Kick in Indoor Soccer

Problem statement: Kicking is one of the most important skills in indoor soccer. Kicking accuracy is an important component of this skill. The instep kick is often used when tacking a penalty kicks, as a combination of increased ball speed and kick accuracy can be maintained. The purpose of this research was to compare selected kinematic parameters of the kicking foot during the performance of successful and unsuccessful penalty kick from a 6 m distance. Approach: Fourteen right footed elite players (seven males and seven females) with an average age of 23±1.7 and 23±2.4 years, height of 182.2±4.73 and 160.7±4.84 cm, weight of 72.4±4.04 and 53.7±4.33 Kg respectively, were selected. For sampling, a kinemetrix 3D motion analyzer with 3 cameras (50 Hz), was used. In the center of the indoor soccer gate a target with a 1 meter radius was marked. The kinematic parameters of successful and unsuccessful kicks were compared by using independent t-test. The level of significance was set to α = 0.05. Results: The results of analysis showed that the values of maximum linear velocity of ankle, knee, the mean value of velocity prior to the kick, angle of the ankle and mean value of angular velocity of the shank and thigh in women before the kick and, the linear velocity of toe, ankle, angular velocity of shank, thigh at the time of impact, the maximum and mean value of velocity in follow through in men before the kick was significantly higher in the unsuccessful kicks than the successful ones. Conclusion: Accurate kicks have lower linear as well as angular velocity compared to the unsuccessful kicks. However, these differences are more pronounced before the kick in women at the time of impact and after the kick in men.

Pulpal Blood Flow Measurement with Ultrasound Doppler Imaging

Introduction This study compared the difference in pulpal blood flow between vital and root-filled teeth by using ultrasound Doppler imaging. Methods To compare the difference in pulpal blood flow between vital and root-filled teeth, 11 patients (mean age, 32.06 years; 3 male, 8 female) who had undergone root canal treatment on the anterior tooth of the maxilla or mandible and had a vital contralateral tooth were examined. Pulpal blood flow measurements were performed on the vital and root canal–treated teeth by using ultrasound Doppler imaging. The parameters examined were the maximum linear velocity (Vas), average linear velocity (Vam), minimum linear velocity (Vakd), pulsation index (PI), and circulation resistance (RI), which are indicators of the pulpal blood flow. The differences between the vital and root-filled teeth were examined by using a paired t test at the 95% confidence interval. Results There were significant differences in the Vas, Vam, Vakd, and RI between the vital and root-filled teeth ( P < .05). With the root-filled teeth, ultrasound Doppler imaging revealed a linear and nonpulsed waveform, whereas the vital teeth showed a pulsed waveform that is characteristic of an arteriole. Conclusions Ultrasound Doppler imaging can detect pulpal blood flow in vital tooth through indicators such as Vas, Vam, Vakd, PI, and RI.

Magnetohydrodynamic processes in the electromagnetic mixing of liquid phase in the ingot on continuous bar- and bloom-casting machines

The influence of electromagnetic mixing of liquid metal in the continuous-casting machine on the quality of continuous-cast bar and bloom depends on the mixing rate. In world practice, the mixing rate is characterized by the maximum linear velocity of the liquid metal in the flow. Physical and mathematical simulation reveals the relations between all the relevant parameters of the mixing stator that affect the mixing rate.

Sustainable wastewater treatment of temporary events: the Dranouter Music Festival case study

Music festivals and other temporary events, such as bicycle races, lay a heavy burden on the surrounding environment. Treatment of the wastewater originating from such events is necessary if no municipal treatment plant is available. This study demonstrated that activated carbon is a performant technique for the treatment of wastewaters originating from these temporary events. Freundlich isotherms and maximum operational linear velocity (6 m/h) were determined on a lab-scale set-up. A pilot-scale set up was used to treat part (5%) of the total volume of the Dranouter Music Festival shower wastewater. On average 90% removal of COD and suspended solids concentration was obtained. Application of the activated carbon filter resulted in the fact that the local discharge limits were met without operational problems.

Markierungsversuche und Modellierung zur Bewertung der Gefährdung eines Trinkwasserbrunnens

A tracer experiment with uranine in a gravel aquifer aimed to assess the risk of a drinking water well near Pratteln, Switzerland, resulting from a contaminated site 760 m further upgradient. The experiment revealed a maximum linear flow velocity of 127 m/d and a mass recovery of 0.93 %. The tracer was also detected at two intermediate monitoring wells. This paper discusses the causes of this high flow velocity. Three different analytical models allowed simulation of the breakthrough curves and determination of transport parameters. A two-dimensional numerical model (FEFLOW) with simplified geometry provided a hydrogeologically consistent and probable explanation of all results. The aquifer is most likely relatively homogeneous, the steep hydraulic gradient (6 ‰) and high conductivity (3 · 10–2 m/s) cause high flow velocities, and most of the tracer passed northeast of the wells. Recently conducted small scale pumping tests largely confirmed this conceptual model. These findings should be considered for future protection measures.

A High-Temperature Superconducting Maglev Dynamic Measurement System

The dynamic measurement of high temperature superconducting (HTS) magnetic levitation (Maglev) vehicle is a very important and difficult problem. In order to investigate the dynamic characteristics behavior of HTS Maglev, an HTS Maglev dynamic measurement system (SCML-03) was successfully developed in Applied Superconductivity Laboratory (ASCLab) of Southwest Jiaotong University, P. R. China. The system is mainly constituted by the circular permanent magnet guideway (PMG), liquid nitrogen vessel, data acquisition and processing, mechanical drive, autocontrol and so on. The PMG is fixed along the circumferential direction of a big circular disk with diameter 1500 mm. The maximum linear velocity of the PMG is about 300 km/h when the circular disk rotates round the central axis at 1280 rpm. The liquid nitrogen vessel with high temperature superconductors is placed above the PMG, and the vessel is not three-dimensional rigid connection with measurement sensor devices. These sensors can detect weak force change from three-dimensional directions. The maximal vertical and horizontal support force of the system are 3350 N and 500 N, respectively. Test process and results of the HTS Maglev dynamic test system are reported.

Mathematically modelling MHD processes in a flow of liquid metal during electromagnetic mixing in semicontinuous steel-casting machines

Mathematical modeling of electromagnetic mixing (EMM) in round semifinished products obtained on a semicontinuous caster at the Elektrostal’ Metallurgical Plant showed that the units developed for EMM in the mold and the zone where solidification of the casting is completed provide for mixing of the liquid phase of the ingot with maximum linear velocities in the range 0.5–0.9 m/sec. Calculated data on the solidification of semifinished products obtained by semi-continuous casting make it possible to determine the position of the liquid phase of the ingot in order to move the carriage of the EMM stator as solidification of the ingot proceeds.