scholarly journals Effect of Flow Rate and Particle Concentration on the Transport and Deposition of Bare and Stabilized Zero-Valent Iron Nanoparticles in Sandy Soil

2019 ◽  
Vol 11 (23) ◽  
pp. 6608
Author(s):  
Ibrahim ◽  
Awad ◽  
Al-Farraj ◽  
Al-Turki
Keyword(s):  
Flow Rate ◽  
Sandy Soil ◽  
Particle Deposition ◽  
Particle Concentration ◽  
Soil Column ◽  
Relative Concentration ◽  
Methyl Cellulose ◽  
Maximum Flow ◽  
Breakthrough Curves ◽  
Zero Valent Iron

Efficient application of nanoscale zero-valent iron (nZVI) particles in remediation processes relies heavily on the ability to modify the surfaces of nZVI particles to enhance their stability and mobility in subsurface layers. We investigated the effect of sodium carboxy-methyl-cellulose (CMC) polymer stabilizer, pH, particle concentration, and flow rate on the transport of nZVI particles in sand columns. Breakthrough curves (BTCs) of nZVI particles indicated that the transport of nZVI particles was increased by the presence of CMC and by increasing the flow rate. The relative concentration (RC) of the eluted CMC–nZVI nanoparticles was larger at pH 9 as compared to RC at pH 7. This is mainly attributed to the increased nZVI particle stability at higher pH due to the increase in the electrostatic repulsion forces and the formation of larger energy barriers. nZVI particle deposition was larger at 0.1 cm min-1 flow due to the increased residence time, which increases the aggregation and settlement of particles. The amount of CMC–nZVI particles eluted from the sand columns was increased by 52% at the maximum flow rate of 1.0 cm min-1. Bare nZVI were mostly retained in the first millimeters of the soil column, and the amount eluted did not exceed 1.2% of the total amount added. Our results suggest that surface modification of nZVI particles was necessary to increase stability and enhance transport in sandy soil. Nevertheless, a proper flow rate, suitable for the intended remediation efforts, must be considered to minimize nZVI particle deposition and increase remediation efficiency.

Flow rate dependent transport of Fluopyram in saturated sandy soil

2020 ◽  
Author(s):  
Mariana Vasconcelos Barroca ◽  
Gilboa Arye ◽  
Zeev Ronen
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Sandy Soil ◽  
Goodness Of Fit ◽  
Soil Column ◽  
Breakthrough Curves ◽  
Low Flow ◽  
Special Focus ◽  
Irreversible Adsorption ◽  
Pulse Input

<p>Velum<sup>®</sup> is a novel contact nematicide with Fluopyram (FL) as active ingredient. Knowledge on its adsorption and transport characteristics is essential for both agricultural and environmental considerations. The main objective of this study was to quantify the transport characteristics of FL in a sandy soil from a non-cultivated area in Arava region, Southern Israel, with a special focus on the behavior in soil after drip application. In this regard, soil column transport experiments under saturated water flow conditions were conducted. In addition to FL, the transport experiments were performed with a bromide tracer. Four factors were examined: (i) pulse concentration, (ii) water flux (ii) pulse size and (iv) interrupted flow. Equilibrium adsorption isotherms were measured by batch experiments. The established breakthrough curves (BTCs) were analyzed with the convection–dispersion equation (CDE) in its chemical equilibrium and non-equilibrium forms. In addition, the validity of a two-site kinetics model was evaluated. All models were examined with and without a term, assuming irreversible sorption. The bromide BTCs were adequately fitted by analytical solutions of the equilibrium CDE using the CXTFIT code, suggesting that physical equilibrium is prevailing. The FL BTCs were fitted with two-site sorption and two kinetic sites models using HYDRUS-1D code. The experimental mass balance analysis demonstrated that the bromide mass was fully recovered, while only part of total FL applied was recovered, in particular, at low flow rate. The comparison between non-interrupted and interrupted water flow demonstrated that at a given flow rate, during the pulse input, the two BTCs are identical. However, following the flow interruption (60 hours), when the flow resumed, a sharp decrease could be observed in FL concentration. Thereafter, the two BTCs are re-converged, exhibiting similar desorption behavior. Possible explanations for FL transport characteristics seems to be low kinetics desorption and/or irreversible adsorption. Additional quantitative insights from the numerical analysis will be presented and discussed based on the goodness of fit and optimized parameters of each model.   </p>

Outcome of Buccal Mucosal Graft Urethroplasty in Long Segment Anterior Urethral Stricture

2020 ◽  
Vol 19 (2) ◽  
pp. 64-68
Author(s):  
Mrinmoy Biswas ◽  
Sudip Das Gupta ◽  
Mohammed Mizanur Rahman ◽  
Sharif Mohammad Wasimuddin
Keyword(s):  
Urethral Stricture ◽  
Flow Rate ◽  
Surgical Outcome ◽  
Simple Technique ◽  
Anterior Segment ◽  
Maximum Flow ◽  
Anastomotic Site ◽  
Buccal Mucosal Graft ◽  
Male Patients

Objective: To assess the success of BMG urethroplasty in long segment anterior urethral stricture. Method: From January 2014 to December 2015, twenty male patients with long anterior segment urethral stricture were managed by BMG urethroplasty. After voiding trial they were followed up at 3 month with Uroflowmetry, RGU & MCU and PVR measurement by USG. Patients were further followed up with Uroflowmetry and PVR at 6 months interval.Successful outcome was defined as normal voiding with a maximum flow rate >15ml /sec and PVR<50 ml with consideration of maximum one attempt of OIU after catheter removal. Results: Mean stricture length was 5.2 cm (range 3-9 cm) and mean follow-up was 15.55 months (range 6-23 months). Only two patients developed stricture at proximal anastomotic site during follow-up. One of them voided normally after single attempt of OIU. Other one required second attempt of OIU and was considered as failure (5%). Conclusion: BMG urethroplasty is a simple technique with good surgical outcome. Bangladesh Journal of Urology, Vol. 19, No. 2, July 2016 p.64-68

Research on an axial-mounted dual magnetostrictive material rods-based electro-hydrostatic actuator

2021 ◽  
pp. 1045389X2110145
Author(s):  
Yuchuan Zhu ◽  
Chang Liu ◽  
Yunze Song ◽  
Long Chen ◽  
Yulei Jiang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Flow Rate ◽  
Flow Distribution ◽  
Maximum Flow ◽  
Magnetostrictive Material ◽  
Simulation Techniques ◽  
Motion State ◽  
New Type ◽  
Output Characteristics ◽  
Active Rectification

In this paper, an electro-hydrostatic actuator driven by dual axial-mounted magnetostrictive material rods-based pumps (MMPs) with a new type of active rectification valve is designed in the current study. Based on flow distribution of the active rectification valve and driving energy provided by two MMPs, the actuator can output continuous and bidirectional displacement. By establishing a mathematical model of the actuating system, using simulation techniques, the change rule of hydraulic cylinder’s motion state caused by different driving signals are studied and analyzed. Test equipment platform is constructed in the laboratory to test the output characteristics and confirm the feasibility of the new concept. The experimental results indicate that the maximum flow rate can reach approximately 2.7 L·min−1, while the operating frequency is 180 Hz.

Kinetics and Equilibrium of Radioactive Metal Adsorption onto Sugarcane Bagasse Waste: Comparison of Batch and Column Adsorption Modes

2021 ◽  
Vol 235 (3) ◽  
pp. 281-294
Author(s):  
Abida Kausar ◽  
Haq Nawaz Bhatti ◽  
Munawar Iqbal
Keyword(s):  
Sugarcane Bagasse ◽  
Flow Rate ◽  
Breakthrough Curves ◽  
Quadratic Model ◽  
Waste Biomass ◽  
Initial Concentration ◽  
Bed Height ◽  
Column Adsorption ◽  
Central Composite ◽  
Bagasse Waste

Abstract Sugarcane bagasse waste biomass (SBWB) efficacy for the adsorption of Zr(IV) was investigated in batch and column modes. The process variables i.e. pH 1–4 (A), adsorbent dosage 0.0–0.3 g (B), and Zr(IV) ions initial concentration 25–200 mg/L (C) were studied. The experiments were run under central composite design (CCD) and data was analysed by response surface methodology (RSM) methodology. The factor A, B, C, AB interaction and square factor A2, C2 affected the Zr(IV) ions adsorption onto SBWB. The quadratic model fitted well to the adsorption data with high R2 values. The effect of bed height, flow rate and Zr(IV) ions initial concentration was also studied for column mode adsorption and efficiency was evaluated by breakthrough curves as well as Bed Depth Service and Thomas models. Bed height and Zr(IV) ions initial concentration enhanced the adsorption of capacity of Zr(IV) ions, whereas flow rate reduced the column efficiency.

Lichen sclerosis–induced long segment anterior urethral stricture: The early outcome of one-stage repair using dorsolateral onlay buccal mucosa graft

2021 ◽  
pp. 039156032110033
Author(s):  
Atef Fathi ◽  
Omar Mohamed ◽  
Osama Mahmoud ◽  
Gamal A Alsagheer ◽  
Ahmed M Reyad ◽  
...  
Keyword(s):  
Success Rate ◽  
Urethral Stricture ◽  
Flow Rate ◽  
Urine Volume ◽  
Maximum Flow ◽  
Maximum Flow Rate ◽  
P Value ◽  
Onlay Graft ◽  
Voiding Symptoms ◽  
Stricture Recurrence

Background: Substitution urethroplasty using buccal mucosal grafts can be performed by several approaches including ventral onlay graft, dorsal onlay graft, or ventral urethrotomy with dorsal inlay graft. Our study aims to evaluate the surgical outcome of dorsolateral buccal mucosal graft for long segment anterior urethral stricture >6 cm in patients with Lichen sclerosus (LS). Methods: A retrospective study included patients who underwent repair for long segment anterior urethral stricture >6 cm due to LS between January 2013 and April 2019. All patients were followed-up at 3, 6, 9, and 12 months postoperatively and then yearly by clinical symptoms, uroflowmetry, and calculation of post-void residual urine volume. Retrograde urethrogram was requested for patients with voiding symptoms or decreased maximum flow rate. Stricture recurrence that required subsequent urethrotomy or urethroplasty was considered failure. The success rate and surgical complications were collected and analyzed. Results: Thirty patients were identified. The median age (range) was 39 (25–61) years and a median (range) stricture length was 8 (6–14) cm. Most of postoperative complications were of minor degree. The success rate at median follow-up of 15 (12–24) months was 86.5%. The median maximum flow rate increased significantly from 6 (2–11) ml/s preoperatively to 18 (range: 6–23) ml/s at the 6th month ( p value < 0.001). Conclusion: Dorsolateral buccal mucosal grafts urethroplasty for long anterior urethral stricture caused by LS has a high success rate and low risk of complications including stricture recurrence.

scholarly journals Improving Output Performance of a Resonant Piezoelectric Pump by Adding Proof Masses to a U-Shaped Piezoelectric Resonator

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 500
Author(s):  
Jian Chen ◽  
Wenzhi Gao ◽  
Changhai Liu ◽  
Liangguo He ◽  
Yishan Zeng
Keyword(s):  
Flow Rate ◽  
Maximum Flow ◽  
Working Fluid ◽  
Driving Voltage ◽  
Piezoelectric Resonator ◽  
Piezoelectric Pump ◽  
Compact Structure ◽  
Output Performance ◽  
Volume Efficiency ◽  
Working Efficiency

This study proposes the improvement of the output performance of a resonant piezoelectric pump by adding proof masses to the free ends of the prongs of a U-shaped piezoelectric resonator. Simulation analyses show that the out-of-phase resonant frequency of the developed resonator can be tuned more efficiently within a more compact structure to the optimal operating frequency of the check valves by adjusting the thickness of the proof masses, which ensures that both the resonator and the check valves can operate at the best condition in a piezoelectric pump. A separable prototype piezoelectric pump composed of the proposed resonator and two diaphragm pumps was designed and fabricated with outline dimensions of 30 mm × 37 mm × 54 mm. Experimental results demonstrate remarkable improvements in the output performance and working efficiency of the piezoelectric pump. With the working fluid of liquid water and under a sinusoidal driving voltage of 298.5 Vpp, the miniature pump can achieve the maximum flow rate of 2258.9 mL/min with the highest volume efficiency of 77.1% and power consumption of 2.12 W under zero backpressure at 311/312 Hz, and the highest backpressure of 157.3 kPa under zero flow rate at 383 Hz.

scholarly journals Maximum Flow Rate of a Single Component, Two-Phase Mixture

1965 ◽  
Vol 87 (1) ◽  
pp. 134-141 ◽  
Author(s):  
F. J. Moody
Keyword(s):  
Flow Rate ◽  
Static Pressure ◽  
Maximum Flow ◽  
Single Component ◽  
Maximum Flow Rate ◽  
Vapor Flow ◽  
Two Phase ◽  
Slip Ratio ◽  
Phase Mixture ◽  
Local Slip

A theoretical model is developed for predicting the maximum flow rate of a single component, two-phase mixture. It is based upon annular flow, uniform linear velocities of each phase, and equilibrium between liquid and vapor. Flow rate is maximized with respect to local slip ratio and static pressure for known stagnation conditions. Graphs are presented giving maximum steam/water flow rates for: local static pressures between 25 and 3,000 psia, with local qualities from 0.01 to 1.00; local stagnation pressures and enthalpies which cover the range of saturation states.

Effect of Blade Angle of Attack and Hub to Tip Ratio on Mass Flow Rate in an Axial Fan at a Fixed Rotational Speed

2008 ◽  
Author(s):  
Mohammad J. Izadi ◽  
Alireza Falahat
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rotational Speed ◽  
Angle Of Attack ◽  
Maximum Flow ◽  
Maximum Flow Rate ◽  
Maximum Mass ◽  
Blade Angle ◽  
Axial Fan

In this investigation an attempt is made to find the best hub to tip ratio, the maximum number of blades, and the best angle of attack of an axial fan with flat blades at a fixed rotational speed for a maximum mass flow rate in a steady and turbulent conditions. In this study the blade angles are varied from 30 to 70 degrees, the hub to tip ratio is varied from 0.2 to 0.4 and the number of blades are varied from 2 to 6 at a fixed hub rotational speed. The results show that, the maximum flow rate is achieved at a blade angle of attack of about 45 degrees for when the number of blades is set equal to 4 at most rotational velocities. The numerical results show that as the hub to tip ratio is decreased, the mass flow rate is increased. For a hub to tip ratio of 0.2, and an angle of attack around 45 degrees with 4 blades, a maximum mass flow rate is achieved.

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