Natural Convection Boiling Potassium Flow Loop

1994 ◽  
Author(s):  
Alexander L. Shimkevich ◽  
Michael N. Ivanovsky ◽  
Valentine A. Morozov ◽  
Kenneth M. Sprouse ◽  
Mohamed S. El-Genk ◽  
...  
Keyword(s):  
Natural Convection ◽  
Flow Loop

A Natural Convection DNA Amplifier

2006 ◽  
Author(s):  
John Daly ◽  
Mark Davies
Keyword(s):  
Natural Convection ◽  
Single Gene ◽  
Reaction Times ◽  
Dna Amplification ◽  
Natural World ◽  
Flow Structures ◽  
Convection Flow ◽  
Flow Visualisation ◽  
Flow Loop ◽  
Image Velocimetry

Natural convection is the driver of innumerable natural world phenomena. Within the laboratory, it offers simplified geometries and flow structures without the need for auxiliary flow inducement, thereby greatly reducing the risk of external contamination within biomedical applications. Outlined in this paper is a polymerase chain reaction (PCR) device which takes advantage of these distinct qualities. PCR has become synonymous with DNA amplification in molecular biology laboratories throughout the world, and at the heart of PCR is thermal cycling. Commonly PCR is accomplished utilising a three stage thermal cycle, however, the device presented employs an alternative two stage cycle which facilitates a simplified natural convection flow structure. The device is, in its fundamental design format, a well-based thermocycler with fast reaction times of 15 minutes. Through the use of Particle Image Velocimetry (PIV) and flow visualisation techniques, a better understanding of the flow structures and their effect on PCR is attained within a device of dimensions of 1 mm depth by 10mm width and 10mm height. This device may present an opportunity for the development of a practical and inexpensive single gene diagnostic tool. Presented here are the findings of the amplification of an 86-bp fragment of the pGEM®-T vector (Promega) within the convective flow loop.

Natural Convection Heat Transfer for a Concentric Tube Thermosiphon

1985 ◽  
Vol 107 (3) ◽  
pp. 583-588 ◽  
Author(s):  
J. L. Steimke
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Single Phase ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Flow Loop ◽  
Model Equations ◽  
Steady Laminar ◽  
Good Agreement

Natural convection heat transfer for a single-phase thermosiphon formed by two concentric tubes and a central rod filled with water is studied theoretically and experimentally. The two annuli between the tubes and the rod are joined at the top and bottom and form a flow loop. The middle tube is heated while the outer tube is cooled. In this one-dimensional model equations for continuity, momentum, and energy for steady laminar flow are written and solved numerically. There is reasonably good agreement between the analytically and experimentally determined temperatures and convective velocities in the thermosiphon.

A novel predictive method for filler coflocculation with cellulose microfibrils

TAPPI Journal ◽  
2019 ◽  
Vol 18 (11) ◽  
pp. 653-664
Author(s):  
IGNACIO DE SAN PIO ◽  
KLAS G. JOHANSSON ◽  
PAUL KROCHAK
Keyword(s):  
Negative Impact ◽  
High Strength ◽  
Strength Properties ◽  
Cellulose Microfibrils ◽  
Paper Strength ◽  
Flow Loop ◽  
Cationic Starch ◽  
Reflectance Measurement ◽  
Drainage Rate ◽  
Complete Study

Different strategies aimed at reducing the negative impact of fillers on paper strength have been the objective of many studies during the past few decades. Some new strategies have even been patented or commercialized, yet a complete study on the behavior of the filler flocs and their effect on retention, drainage, and formation has not been found in literature. This type of research on fillers is often limited by difficulties in simulating high levels of shear at laboratory scale similar to those at mill scale. To address this challenge, a combination of techniques was used to compare preflocculation (i.e., filler is flocculated before addition to the pulp) with coflocculation strategies (i.e., filler is mixed with a binder and flocculated before addition to the pulp). The effect on filler and fiber flocs size was studied in a pilot flow loop using focal beam reflectance measurement (FBRM) and image analysis. Flocs obtained with cationic polyacrylamide (CPAM) and bentonite were shown to have similar shear resistance with both strategies, whereas cationic starch (CS) was clearly more advantageous when coflocculation strategy was used. The effect of flocculation strategy on drainage rate, STFI formation, ash retention, and standard strength properties was measured. Coflocculation of filler with CPAM plus bentonite or CS showed promising results and produced sheets with high strength but had a negative impact on wire dewatering, opening a door for further optimization.

Natural convection in tilted square cavities with triangular shaped top cold wall

2009 ◽  
Vol 39 (0) ◽  
Author(s):  
Tamanna Sultana ◽  
Sumon Saha ◽  
Goutam Saha ◽  
Md Quamrul Islam
Keyword(s):  
Natural Convection ◽  
Cold Wall
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