The association of E. coli and soil particles in overland flow

2006 ◽  
Vol 54 (3) ◽  
pp. 153-159 ◽  
Author(s):  
R.W. Muirhead ◽  
R.P. Collins ◽  
P.J. Bremer
Keyword(s):  
Flow Rate ◽  
Overland Flow ◽  
Infiltration Rate ◽  
Soil Tillage ◽  
Soil Matrix ◽  
Flow Rates ◽  
Soil Particles ◽  
E Coli ◽  
The Impact ◽  
Saturation Excess

The removal of E. coli from overland flow under saturation-excess runoff conditions was investigated in experimental field plots that were 1 m wide and 5 m long. Variation in the attenuation of bacteria and distance transported was quantified under contrasting flow conditions. In addition, the impact of soil tillage upon microbial attenuation was examined by comparing results derived from grassed plots (intact) with those subject to tillage with the soil left bare (cultivated). For intact plots subjected to a flow of 2 L/min, 27% of the E. coli in the flow was removed after 5 m with removal following a logarithmic function with respect to distance. For the higher flow rates of 6 L/min and 20 L/min, no attenuation trend was observed over this distance. E. coli removal during flow across the cultivated plots was significantly greater compared to the intact plots. This was attributed to a greater infiltration rate in the cultivated plots (due to the tillage) which promoted a greater volume of flow to pass through the soil matrix, providing the opportunity for filtration and adsorption of microbes. Logarithmic trends with respect to distance were observed for all flow rates tested on the cultivated plots (2, 6 and 20 L/min). Total removal after 5 m at a flow rate of 2 L/min was 41% and again removal efficiency decreased as the flow rate increased. Analysis of the transported state of the E. coli revealed that the bacteria were being transported predominantly in particles less than 20 μm in diameter and were not attached to large (dense) soil particles. The limited removal (<50%) of bacteria from overland flow under saturation-excess runoff conditions in these experiments appeared, therefore, to be primarily due to a lack of settling or deposition. Instead, most bacteria remained entrained within the overland flow down the length of the plots.

scholarly journals Interaction of Escherichia coli and Soil Particles in Runoff

2006 ◽  
Vol 72 (5) ◽  
pp. 3406-3411 ◽  
Author(s):  
Richard William Muirhead ◽  
Robert Peter Collins ◽  
Philip James Bremer
Keyword(s):  
Escherichia Coli ◽  
Overland Flow ◽  
Breakthrough Curves ◽  
Model System ◽  
Scale Model ◽  
Soil Matrix ◽  
Soil Particles ◽  
E Coli ◽  
Flow Transport ◽  
Large Soil

ABSTRACT A laboratory-scale model system was developed to investigate the transport mechanisms involved in the horizontal movement of bacteria in overland flow across saturated soils. A suspension of Escherichia coli and bromide tracer was added to the model system, and the bromide concentration and number of attached and unattached E. coli cells in the overland flow were measured over time. Analysis of the breakthrough curves indicated that the E. coli and bromide were transported together, presumably by the same mechanism. This implied that the E. coli was transported by advection with the flowing water. Overland-flow transport of E. coli could be significantly reduced if the cells were preattached to large soil particles (>45 μm). However, when unattached cells were inoculated into the system, the E. coli appeared to attach predominantly to small particles (<2 μm) and hence remained unattenuated during transport. These results imply that in runoff generated by saturation-excess conditions, bacteria are rapidly transported across the surface and have little opportunity to interact with the soil matrix.

Effect of Formula Type and Preparation on International Dysphagia Diet Standardisation Initiative Thickness Level and Milk Flow Rates From Bottle Teats

2021 ◽  
Vol 30 (1) ◽  
pp. 260-265
Author(s):  
Britt F. Pados ◽  
Victoria Feaster
Keyword(s):  
Gastroesophageal Reflux ◽  
Infant Formula ◽  
Flow Rate ◽  
Infant Formulas ◽  
Testing Methods ◽  
Flow Rates ◽  
Milk Flow ◽  
Thin Liquids ◽  
The Impact ◽  
Formula Type

Purpose The purpose of this study was to evaluate the effect of infant formula type and preparation (i.e., ready-to-feed vs. powder) on International Dysphagia Diet Standardisation Initiative (IDDSI) thickness level and milk flow rates from bottle teats/nipples. Method The ready-to-feed and powder formulations of the following products were tested for IDDSI thickness level, using IDDSI guidelines, and for milk flow rate, using established flow testing methods: Similac Advance, Similac For Spit-Up, Enfamil Infant, and Enfamil A.R. Analysis of variance was used to compare flow rates among formula types/preparations. Results Enfamil A.R. ready-to-feed was classified as IDDSI “slightly thick.” All other formula types/preparations were found to be IDDSI “thin” liquids. The standard infant formulas (Similac Advance and Enfamil Infant) had comparable flow rates to each other, regardless of preparation (ready-to-feed and powder). The gastroesophageal reflux–specific formulas (Similac For Spit-Up and Enfamil A.R.) had slower flow rates than the standard formulas; within this category, there were significant differences in flow rates between ready-to-feed and powder. Enfamil A.R. powder had the slowest flow rate, but was the most variable. Conclusion For infants with difficulty coordinating sucking, swallowing, and breathing, clinicians and parents should consider the impact that changes to infant formula type and preparation may have on the infant's ability to safely feed.

Assessment of the impact of water parameters on the flow rate of ceramic pot filters in a long-term experiment

2015 ◽  
Vol 15 (6) ◽  
pp. 1425-1432 ◽  
Author(s):  
C. Salvinelli ◽  
A. C. Elmore
Keyword(s):  
Flow Rate ◽  
Water Production ◽  
Premature Failure ◽  
Initial Flow ◽  
Flow Rates ◽  
Treated Water ◽  
Long Term Study ◽  
The Impact ◽  
The Relationship

Poor water quality is a major contributing factor to disease in developing countries. Silver-coated ceramic pot filters (CPFs) are a relatively common form of household water treatment system (HWTS) representing an effective and sustainable technology for poor communities. Water production seems to be the major limiting factor of the CPF's lifetime and sustainability since low flow rates do not produce an adequate daily volume of treated water. This paper describes a long-term study of CPF flow rates under controlled conditions using three different water sources. The relationship between water characteristics and flow rate was assessed with the intent of identifying the principal parameters that impact CPF water production. The study concluded that turbidity seems to be the principal indicator in determining CPF lifetime in terms of quantity of treated water. There is no evidence that biological activity also contributes to premature failure of CPFs and the data did not indicate that chemical precipitation is responsible for the filter clogging. Manufacturers commonly conduct initial flow rate tests using clear water as a measure of quality assurance. However, the relationship between initial flow rate and average flow rate during the lifetime of the CPF should be further studied.

Experimental Study on Discharge Coefficients of Windward Window in Buildings with Wind-Driven Cross Ventilation

2014 ◽  
Vol 1008-1009 ◽  
pp. 1061-1067
Author(s):  
Qiao Ning Wang ◽  
Yan Ling Guan ◽  
Qi Hai Liao
Keyword(s):  
Flow Rate ◽  
Natural Ventilation ◽  
Discharge Coefficient ◽  
Static Pressure ◽  
Flow Rates ◽  
Discharge Coefficients ◽  
Window Opening ◽  
Static Pressure Difference ◽  
Window Area ◽  
The Impact

Focus on the prediction of flow rates in buildings under natural ventilation, the investigation conducted a series of model rooms with cross ventilation. The impact of window-wall ratios, windows configurations as well as corresponding flow rates was investigated. The object of this investigation is to analyze characteristics of windward window opening discharge coefficient by measuring static pressure difference and the flow rate through windows. The conclusion are as follows: For large openings, the discharge coefficient of windward window opening increases as the window-wall ratio grows up; With windward window-wall ratio of 44.4% and 11.1%, the discharge coefficient of windward openings is almost irrelevant to flow rate and less affected by leeward window area; However, with windward window-wall ratio of 2.78%, the discharge coefficient increases slightly as flow rate rises, and the larger the area of leeward opening is, the smaller the discharge coefficient of windward opening becomes.

scholarly journals Experimental study of in-situ W/O emulsification during the injection of MgSO4 and Na2CO3 solutions in a glass micromodel

2020 ◽  
Vol 75 ◽  
pp. 87
Author(s):  
Sepideh Palizdan ◽  
Hossein Doryani ◽  
Masoud Riazi ◽  
Mohammad Reza Malayeri
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
Oil Recovery ◽  
Deionized Water ◽  
Water Flooding ◽  
Flow Rates ◽  
Glass Micromodel ◽  
The Impact ◽  
Emulsification Process

In-situ emulsification of injected brines of various types is gaining increased attention for the purpose of enhanced oil recovery. The present experimental study aims at evaluating the impact of injecting various solutions of Na2CO3 and MgSO4 at different flow rates resembling those in the reservoir and near wellbore using a glass micromodel with different permeability regions. Emulsification process was visualized through the injection of deionized water and different brines at different flow rates. The experimental results showed that the extent of emulsions produced in the vicinity of the micromodel exit was profoundly higher than those at the entrance of the micromodel. The injection of Na2CO3 brine after deionized water caused the impact of emulsification process more efficiently for attaining higher oil recovery than that for the MgSO4 brine. For instance, the injection of MgSO4 solution after water flooding increased oil recovery only up to 1%, while the equivalent figure for Na2CO3 was 28%. It was also found that lower flow rate of injection would cause the displacement front to be broadened since the injected fluid had more time to interact with the oil phase. Finally, lower injection flow rate reduced the viscous force of the displacing fluid which led to lesser occurrence of viscous fingering phenomenon.

scholarly journals GROWTH AND PROTEIN CONTENT OF Ulva prolifera MAINTAINED AT DIFFERENT FLOW RATES IN INTEGRATED AQUACULTURE SYSTEM

2017 ◽  
Vol 9 (2) ◽  
pp. 429-441
Author(s):  
Wastu Ayu Diamahesa ◽  
Toshiro Masumoto ◽  
Dedi Jusadi ◽  
Mia Setiawati
Keyword(s):  
Protein Content ◽  
Flow Rate ◽  
Ammonia Nitrogen ◽  
Ulva Prolifera ◽  
Average Weight ◽  
Flow Rates ◽  
Integrated Aquaculture ◽  
Aquaculture System ◽  
Total Ammonia ◽  
The Impact

Efforts to reduce the impact of waste improvement on degradation of water quality can be transferred by utilization of inorganic waste as a source of seaweed nutrition. This study aimed to determine the growth and protein content of Ulva prolifera maintained at different flow rates in integrated aquaculture system. 9 Yellowtail stocked with 5.095 g with an average weight of 566.11±81.51 g were kept in 540 L tank for 24 days, by water flowing at the rate of 10 L min-1. Water from the fish tank was distributed into the sediment tank and go to 6 Ulva tanks with the flow rate of 0.5, 1.0 and 1.5 L min-1. Test parameters measured were growth performance of Yellowtail, biomass of Ulva prolifera, protein content of Ulva prolifera, and total ammonia nitrogen. The measurement results showed that the biomass of fish increased to 5.408 g, then biomass of Ulva increased to 42 g, 156 g and 155 g for flow rate of 0.5 L, 1 L and 1.5 L min-1, respectively. The protein content of Ulva for all the treatments was the same (P> 0.05). A total of ammonia in the tank outlet of Ulva (0.0202 - 0.1137 mg N L-1) were smaller than those were in the inlet (0.0286 - 0.1394 mg N L-1).

scholarly journals Response of the Meltwater Erosion to Runoff Energy Consumption on Loessal Slopes

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1522 ◽  
Author(s):  
Tian Wang ◽  
Peng Li ◽  
Jingming Hou ◽  
Zhanbin Li ◽  
Zongping Ren ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Soil Erosion ◽  
Flow Rate ◽  
Erosion Rate ◽  
Frozen Soil ◽  
Soil Conditions ◽  
Soil Slope ◽  
Flow Rates ◽  
Soil Erosion Rate ◽  
The Impact

Soil properties are influenced by freeze-thaw, which in turn influences soil erosion. Despite this, only a few studies have investigated the impacts on soil hydrodynamic processes. The objective of this study was to evaluate the impact of soil freezing conditions on runoff, its energy consumption, and soil erosion. A total of 27 laboratory-concentrated meltwater flow experiments were performed to investigate the soil erosion rate, the runoff energy consumption, and the relationship between the soil erosion rate and runoff energy consumption by concentrated flow under combinations of three flow rates (1, 2, and 4 L/min) and three soil conditions (unfrozen, shallow-thawed, and frozen). The individual and combined effects of soil condition, flow rate, and runoff energy consumption on the soil erosion rate were analyzed. For the same flow rate, the shallow-thawed and frozen slope produced mean values of 3.08 and 4.53 times the average soil erosion rates compared to the unfrozen slope, respectively. The number of rills in the unfrozen soil slope were 4, 3, and 2 under the flow rate of 1, 2, and 4 L/min, respectively. The number of rills in the thawed-shallow and frozen soil slope were all 1 under the flow rate of 1, 2, and 4 L/min. The rill displayed disconnected distribution patterns on the unfrozen slope, but a connected rill occurred on the shallow-thawed and frozen slopes. The average rill width on unfrozen, thawed-shallow, and frozen soil slopes increased by 1.87 cm, 4.38 cm, and 1.68 cm as the flow rate increased from 1 L/min to 4 L/min. There was no significant difference in the rill length on the frozen slope under different flow rates (p > 0.05). The runoff energy consumption ranged from unfrozen > shallow-thawed > frozen slopes at the same flow rate. The soil erosion rate had a linear relationship with runoff energy consumption. The spatial distribution of the runoff energy implied that soil erosion was mainly sourced from the unfrozen down slope, shallow-thawed upper slope, and frozen full slope.

scholarly journals Variación espacio-temporal de los procesos hidrológicos del suelo en viñedos con elevadas pendientes (Valle del Ruwer-Mosela, Alemania)

2016 ◽  
Vol 42 (1) ◽  
pp. 281 ◽  
Author(s):  
J. Rodrigo-Comino ◽  
M. Seeger ◽  
J. M. Senciales ◽  
J. D. Ruiz-Sinoga ◽  
J. B. Ries
Keyword(s):  
Hydraulic Conductivity ◽  
Infiltration Rate ◽  
Soil Tillage ◽  
Soil Conditions ◽  
Spatial And Temporal Variability ◽  
Soil Matrix ◽  
Tillage Practices ◽  
Infiltration Rates ◽  
Steep Slopes ◽  
Guelph Permeameter

The vineyards of Ruwer-Mosel valley (Germany) cultivated on steep slopes showed a high spatial and temporal variability of hydrological dynamics. Forty two experiments were carried out using a Guelph permeameter in old and young vines to measure the infiltration rates, the hydraulic conductivity and the soil matrix flux potential. The essays were performed before (spring-summer) and after (autumn) the harvest with dry soil conditions and without soil tillage signals, and with humid soil conditions, signals of soil farming (wheel traffic and footprints) and a decrease of organic matter, respectively. In general, the results of the young vineyards were higher than the values of the old vineyards. Furthermore, all the rates increased after the harvest. For the young vineyards, the most elevated values were registered on the middle slope (398.5 mm h-1 infiltration rate, 89.2 mm h-1 hydraulic conductivity and 62.8 mm2 h-1 soil matrix flux potential). For its part, a decrease of the infiltration from the upper slope to the foot slope was observed (from 42.5 to 16.8 mm h-1). Hydraulic conductivity and soil matrix flux potential showed the same hydro-dynamic: from 13.2 to 5.4 mm h-1 and from 5.5 to 2.5 mm2 h-1, respectively. Finally, it was observed that the most correlated factor with these hydrological processes was the soil moisture content and the soil tillage practices.

Impact of flow rate on lactate uptake and gluconeogenesis in glucagon-stimulated perfused livers

2006 ◽  
Vol 290 (1) ◽  
pp. E185-E191 ◽  
Author(s):  
Ken D. Sumida ◽  
Jerry H. Urdiales ◽  
Casey M. Donovan
Keyword(s):  
Flow Rate ◽  
Dominant Role ◽  
Bicarbonate Buffer ◽  
Flow Rates ◽  
Exponential Decline ◽  
Actual Flow Rate ◽  
Actual Flow ◽  
Lactate Uptake ◽  
The Impact ◽  
Bovine Erythrocytes

The impact of reduced hepatic flow on lactate uptake and gluconeogenesis was examined in isolated glucagon-stimulated perfused livers from 24-h-fasted rats. After surgical isolation, livers were perfused (single pass) for 30 min with Krebs-Henseleit (KH) bicarbonate buffer, fresh bovine erythrocytes (hematocrit ∼20%), and no added substrate. After this “washout” period, steady-state perfusions were initiated with a second reservoir containing the KH buffer, bovine erythrocytes, [U-14C]lactate (10,000 dpm/ml), lactate (2.5 mM), and glucagon (250 μg/ml). Perfusion flow rate was adjusted to one of five rates (i.e., 1.8, 2.7, 3.9, 7.4, and 11.0 ml·min−1·100 g body wt−1). After the perfusion, the liver was dissected out and weighed so as to establish the actual flow rate per gram of liver. The resulting flow rates ranged from 0.52 to 4.03 ml·min−1·g liver−1. As a function of flow rate, lactate uptake rose in a hyperbolic fashion to an apparent plateau of 2.34 μmol·min−1·g liver−1. Fractional extraction (FX) of lactate from the perfusate demonstrated an exponential decline with increased flow rates ( r = 0.97). At flow rates above 1.0 ml·min−1·g liver−1, adjustments in FX compensated for changes in lactate delivery, resulting in steady rates of lactate uptake and gluconeogenesis. Below 1.0·min−1·g liver−1 the increased FX was unable to compensate for the decline in lactate delivery and lactate uptake declined rapidly. Gluconeogenesis demonstrated similar kinetics to lactate uptake, reflecting its dominant role among pathways for lactate removal under the current conditions.

Identification of Dynamic Coefficients of a Five-Pad Tilting Pad Journal Bearing Up to Highest Surface Speeds

2021 ◽  
Author(s):  
Philipp Zemella ◽  
Thomas Hagemann ◽  
Bastian Pfau ◽  
Hubert Schwarze
Keyword(s):  
Flow Rate ◽  
Journal Bearing ◽  
Flow Rates ◽  
Damping Coefficients ◽  
Dynamic Coefficients ◽  
Tilting Pad ◽  
Oil Flow ◽  
Bearing Loads ◽  
Tilting Pad Journal Bearing ◽  
The Impact

Abstract This paper presents measurement results for a five-pad tilting-pad journal bearing in load between pivot configuration. The bearing is characterized by a nominal diameter of 100 mm, a length of 90 mm, and a pivot offset of 0.6. Investigations include results for surface speeds between 25 and 120 m/s and specific bearing loads ranging from 0.0 to 3.0 MPa and different lube oil flow rates. Dynamic excitation test are performed with excitation frequencies up to 400 Hz to evaluate dynamic coefficients of a stiffness (K) and damping (C) KC-model, and additionally, a KCM-model using additional virtual mass (M) coefficients. The impact of surface speed, bearing load, and oil flow rate on measured and predicted KCM-coefficients is investigated. Measured and predicted results can be well fitted to a KCM-model and show a significant influence of the ratio between fluid film and pivot support stiffness on the speed dependent characteristic of bearing stiffness coefficients. However, the impact of this ratio on damping coefficients is considerably lower. Further investigations on the impact of oil flow rates indicate that a significant decrease of direct damping coefficients exists below a certain level of starvation. Above this limit, direct damping coefficients are nearly independent of oil flow rate. Results are analyzed in detail and demands on improvements for predictions are derived.

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