scholarly journals An innovative technique of harvesting soil gas as a highly efficient source of 222Rn for calibration applications in a walk-in type chamber: part-1

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
N. Karunakara ◽  
Trilochana Shetty ◽  
B. K. Sahoo ◽  
K. Sudeep Kumara ◽  
B. K. Sapra ◽  
...  
Keyword(s):  
High Strength ◽  
Soil Gas ◽  
Dynamic Mode ◽  
Safety Issues ◽  
Highly Efficient ◽  
Mode Of Operation ◽  
Flow Through ◽  
Calibration Chamber ◽  
A New Technique ◽  
Calibration Laboratories

Abstract The paper describes a novel technique to harvest 222Rn laden air from soil gas of natural origin as a highly efficient source of 222Rn for calibration applications in a walk-in type 222Rn calibration chamber. The technique makes use of a soil probe of about 1 m to draw soil gas, through a dehumidifier and a delay volume, using an air pump to fill the calibration chamber. 222Rn concentration in the range of a few hundred Bq m−3 to a few tens of kBq m−3 was easily attained in the chamber of volume 22.7 m3 within a short pumping duration of 1 h. A new technique referred to as “semi-dynamic mode of operation” in which soil gas is injected into the calibration chamber at regular intervals to compensate for the loss of 222Rn due to decay and leak is discussed. Harvesting soil gas has many important advantages over the traditional methods of 222Rn generation for calibration experiments using finite sources such as solid flow-through, powdered emanation, and liquid sources. They are: (1) soil gas serves as an instantaneous natural source of 222Rn, very convenient to use unlike the high strength 226Ra sources used in the calibration laboratories, and has no radiation safety issues, (2) does not require licensing from the regulatory authority, and (3) it can be used continuously as a non-depleting reservoir of 222Rn, unlike other finite sources. The newly developed technique would eliminate the need for expensive radioactive sources and thereby offers immense application in a variety of day to day experiments—both in students and research laboratories.

scholarly journals A periodic pumping technique of soil gas for 222Rn stabilization in large calibration chambers: part 2—theoretical formulation and experimental validation

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Trilochana Shetty ◽  
Y. S. Mayya ◽  
K. Sudeep Kumara ◽  
B. K. Sahoo ◽  
B. K. Sapra ◽  
...  
Keyword(s):  
Large Volume ◽  
Mathematical Formulation ◽  
Temporal Stability ◽  
High Strength ◽  
Soil Gas ◽  
Dynamic Mode ◽  
Theoretical Formulation ◽  
Safety Issues ◽  
Injection Pump ◽  
Calibration Chamber

Abstract In an adjoining publication, we demonstrated the novel technique to harvest soil gas of natural origin as a highly efficient source of 222Rn for calibration applications in a large volume 222Rn calibration chamber. Its advantages over the use of conventional high strength 226Ra sources, such as the capability to serve as a non-depleting reservoir of 222Rn and achieve the desired concentration inside the calibration chamber within a very short time, devoid of radiation safety issues in source handling and licensing requirements from the regulatory authority, were discussed in detail. It was also demonstrated that stability in the 222Rn concentration in large calibration chambers could be achieved within ± 20% deviation from the desired value through a semi-dynamic mode of injection in which 222Rn laden air was periodically pumped to compensate for its loss due to leak and decay. The necessity of developing a theory for determining the appropriate periodicity of pumping was realized to get good temporal stability with a universally acceptable deviation of ≤ ± 10% in the 222Rn concentration. In this paper, we present a mathematical formulation to determine the injection periods (injection pump ON and OFF durations) for the semi-dynamic operation to achieve long term temporal stability in the 222Rn concentration in the chamber. These computed pumping parameters were then used to efficiently direct the injection of soil gas into the chamber. We present the mathematical formulation, and its experimental validations in a large volume calibration chamber (22 m3). With this, the temporal stability of 222Rn concentration in the chamber was achieved with a deviation of ~ 3% from the desired value.

The application of the root zone method for the treatment and reuse of high-strength abattoir waste in Mexico

1997 ◽  
Vol 35 (5) ◽  
pp. 271-278 ◽  
Author(s):  
Fermin Rivera ◽  
Alan Warren ◽  
Colin R. Curds ◽  
Esperanza Robles ◽  
Alejandro Gutierrez ◽  
...  
Keyword(s):  
Treatment Process ◽  
Root Zone ◽  
Ornamental Plants ◽  
High Strength ◽  
Faecal Coliforms ◽  
Treatment Efficiency ◽  
Zone Method ◽  
Stage System ◽  
Flow Through ◽  
Two Stages

A two-stage system for treating high-strength wastewater from an abattoir at Pachuca, Mexico is described. The system consists of an anaerobic digester followed by an artificially-constructed wetland which employs horizontal subsurface flow through the root zone of emergent hydrophytes planted in a gravel substrate. The main goals of this study were to monitor the treatment efficiency of the system for the first twelve months of operation and to assess the suitability of the effluent for irrigation purposes. The treatment efficiency during the twelve month period was generally good with mean removal efficiencies of 88.5% for BOD5, 87.4% COD, 89% suspended solids, 73.6% organic nitrogen and >99% faecal coliforms. Removal rates were generally poor for orthophosphates, NH3-nitrogen and NO3-nitrogen. The differing roles of the two stages in the treatment process are discussed. Although not suitable for irrigating crops, the effluent is being successfully used for the irrigation of ornamental plants and recreational lands.

Highly Efficient and Recyclable Carbon‐Nanofiber‐Based Aerogels for Ionic Liquid–Water Separation and Ionic Liquid Dehydration in Flow‐Through Conditions

2019 ◽  
Vol 31 (39) ◽  
pp. 1903418 ◽  
Author(s):  
Li Zhi Guan ◽  
María C. Gutiérrez ◽  
María J. Roldán‐Ruiz ◽  
Ricardo Jiménez ◽  
M. Luisa Ferrer ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Liquid Water ◽  
Carbon Nanofiber ◽  
Water Separation ◽  
Highly Efficient ◽  
Flow Through

Effect of Counter Punch Pressure on Springback of High Strength Steel Sheet

2014 ◽  
Vol 939 ◽  
pp. 305-312 ◽  
Author(s):  
Komgrit Lawanwong ◽  
Hiroshi Hamasaki ◽  
Ryutaro Hino ◽  
Fusahito Yoshida
Keyword(s):  
Final Stage ◽  
Steel Sheet ◽  
Fe Simulation ◽  
Kinematic Hardening ◽  
High Strength ◽  
Dual Phase ◽  
Clamping Force ◽  
Bending Process ◽  
A New Technique ◽  
Punch Pressure

To reduce springback in U-bending the present paper proposes a new technique where the bottom of a U-bent part is clamped between a punch and a counter-punch during bending and it is pushed up with the counter punch at the final stage. The effect of counter punch pressure, both in sheet clamping and bottoming, was investigated by performing experiments on dual phase 590MPa and TRIP 780MPa HSS sheets. From the experiment, an appropriate combination of the clamping force and the final pushing-up force was found where springback was reduced to almost zero. To investigate the mechanism of the reduction of springback in the above three-step U-bending process, FE simulation of the bending with PAM-STAMP 2G was also conducted where the advanced kinematic hardening Yoshida-Uemori model was employed.

A highly efficient flow-through electro-Fenton system enhanced with nitrilotriacetic acid for phenol removal at neutral pH

2019 ◽  
Vol 697 ◽  
pp. 134173 ◽  
Author(s):  
Yinqiao Zhang ◽  
Qizhan Zhang ◽  
Sijin Zuo ◽  
Minghua Zhou ◽  
Yuwei Pan ◽  
...  
Keyword(s):  
Nitrilotriacetic Acid ◽  
Phenol Removal ◽  
Neutral Ph ◽  
Highly Efficient ◽  
Flow Through ◽  
Fenton System

scholarly journals Rotating Disk Apparatus: Types, Developments and Future Applications

2016 ◽  
Vol 10 (8) ◽  
pp. 198 ◽  
Author(s):  
Musaab K. Rashed ◽  
Hayder A. Abdulbari ◽  
Mohamad Amran Mohd Salleh ◽  
M. Halim Shah Ismail
Keyword(s):  
Reaction Rate ◽  
Rotating Disk ◽  
Rotating Disk Electrode ◽  
Solid Surfaces ◽  
Dynamic Mode ◽  
Power Losses ◽  
The Past ◽  
Consumption Reduction ◽  
Mode Of Operation ◽  
Mode Of Transportation

Power consumption reduction investigations attracted the attention of enormous numbers of researchers in the past few decades due to its high academic and economic impacts. The pumping power losses during the transportation of crude oils are considered as one of the main power consuming applications due to the turbulent mode of transportation. Investigating the possible solutions for this problem is expensive and time consuming due to the large apparatuses needed to simulate the flow in real pipelines. Rotating disk apparatus (RDA) is an instrument mainly comprising a rotating disk and an electrical motor to rotate the disk, which was implemented as an efficient and economical path to simulate what can be done in pipelines through generating a controlled degree of turbulence. This technique was also used in many other scientific applications due to its dynamic mode of operation. For example, a rotating disk electrode was used in electrodeposition processes and to characterize deposition film thickness and uniformity. The rotating disk reactor was employed to investigate the reaction rate between fluids and solid surfaces. The present work evaluates the RDA from different prospective and applications in order to introduce it as an efficient research tools for future dynamic investigations.

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